Trial Outcomes & Findings for Carboplatin, Etoposide, and Atezolizumab With or Without Trilaciclib (G1T28), a CDK4/6 Inhibitor, in Extensive-Stage SCLC (NCT NCT03041311)

Last Updated: 2025-09-25

Results Overview

Duration of severe neutropenia (DSN; days) was defined as the number of days from the date of the first absolute neutrophil count (ANC) value of \<0.5 × 10⁹/L observed between start of cycle and end of cycle to the date of the first ANC value ≥0.5 × 10⁹/L that met the following criteria: (1) occurred after the ANC value of \<0.5 × 10⁹/L and (2) no other ANC values \<0.5 × 10⁹/L occurred between this day and end of cycle. DSN was set to 0 for patients who did not experience severe neutropenia in a cycle, including those that were randomized and not treated. Data from unscheduled visits and the actual assessment date (rather than visit date) were included in the derivation.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

107 participants

Primary outcome timeframe

Evaluated for Cycle 1 of the Induction Period (i.e., from randomization to the end of Cycle 1, each cycle = 21 days).

Results posted on

2025-09-25

Participant Flow

Participant milestones

Participant milestones
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Overall Study STARTED	54	53
Overall Study COMPLETED	0	0
Overall Study NOT COMPLETED	54	53

Reasons for withdrawal

Reasons for withdrawal
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Overall Study Death	39	42
Overall Study Lost to Follow-up	0	1
Overall Study Withdrawal by Subject	8	5
Overall Study Sponsor Terminated Study	2	4
Overall Study Disease Progression	3	1
Overall Study Randomized in error, did not receive drug	2	0

Baseline Characteristics

Carboplatin, Etoposide, and Atezolizumab With or Without Trilaciclib (G1T28), a CDK4/6 Inhibitor, in Extensive-Stage SCLC

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily on Days prior to E/P/A 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity or discontinuation by the patient or investigator.	Total n=107 Participants Total of all reporting groups
Age, Categorical <=18 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Age, Categorical Between 18 and 65 years	27 Participants n=5 Participants	27 Participants n=7 Participants	54 Participants n=5 Participants
Age, Categorical >=65 years	27 Participants n=5 Participants	26 Participants n=7 Participants	53 Participants n=5 Participants
Age, Continuous	63 years STANDARD_DEVIATION 8.4 • n=5 Participants	64 years STANDARD_DEVIATION 8.3 • n=7 Participants	64 years STANDARD_DEVIATION 8.3 • n=5 Participants
Sex: Female, Male Female	13 Participants n=5 Participants	19 Participants n=7 Participants	32 Participants n=5 Participants
Sex: Female, Male Male	41 Participants n=5 Participants	34 Participants n=7 Participants	75 Participants n=5 Participants
Race/Ethnicity, Customized White	53 Participants n=5 Participants	51 Participants n=7 Participants	104 Participants n=5 Participants
Race/Ethnicity, Customized Black or African American	0 Participants n=5 Participants	1 Participants n=7 Participants	1 Participants n=5 Participants
Race/Ethnicity, Customized Native Hawaiian or Pacific Islander	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Race/Ethnicity, Customized Other	0 Participants n=5 Participants	1 Participants n=7 Participants	1 Participants n=5 Participants
Region of Enrollment Latvia	3 participants n=5 Participants	3 participants n=7 Participants	6 participants n=5 Participants
Region of Enrollment United States	20 participants n=5 Participants	22 participants n=7 Participants	42 participants n=5 Participants
Region of Enrollment Ukraine	11 participants n=5 Participants	8 participants n=7 Participants	19 participants n=5 Participants
Region of Enrollment Bulgaria	6 participants n=5 Participants	7 participants n=7 Participants	13 participants n=5 Participants
Region of Enrollment France	0 participants n=5 Participants	2 participants n=7 Participants	2 participants n=5 Participants
Region of Enrollment Estonia	2 participants n=5 Participants	3 participants n=7 Participants	5 participants n=5 Participants
Region of Enrollment Spain	1 participants n=5 Participants	3 participants n=7 Participants	4 participants n=5 Participants
Region of Enrollment Georgia	11 participants n=5 Participants	5 participants n=7 Participants	16 participants n=5 Participants
Body Weight at Screening	79.2 kg STANDARD_DEVIATION 17.32 • n=5 Participants	72.4 kg STANDARD_DEVIATION 14.42 • n=7 Participants	75.8 kg STANDARD_DEVIATION 16.25 • n=5 Participants
Height at Screening	171.1 cm STANDARD_DEVIATION 7.62 • n=5 Participants	168.6 cm STANDARD_DEVIATION 10.21 • n=7 Participants	169.9 cm STANDARD_DEVIATION 9.04 • n=5 Participants
BMI at Screening	27.10 kg/m² STANDARD_DEVIATION 5.907 • n=5 Participants	25.45 kg/m² STANDARD_DEVIATION 4.618 • n=7 Participants	26.28 kg/m² STANDARD_DEVIATION 5.347 • n=5 Participants
Body Surface Area (m²) at Screening	1.91 m² STANDARD_DEVIATION 0.198 • n=5 Participants	1.82 m² STANDARD_DEVIATION 0.205 • n=7 Participants	1.86 m² STANDARD_DEVIATION 0.205 • n=5 Participants
ECOG Performance Status 0-1	46 Participants n=5 Participants	46 Participants n=7 Participants	92 Participants n=5 Participants
ECOG Performance Status 2	8 Participants n=5 Participants	7 Participants n=7 Participants	15 Participants n=5 Participants

PRIMARY outcome

Timeframe: Evaluated for Cycle 1 of the Induction Period (i.e., from randomization to the end of Cycle 1, each cycle = 21 days).

Population: Intent-to-treat (ITT) analysis set included all randomized patients. Analysis using the ITT analysis set were conducted on the basis of the randomly assigned treatment.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Duration of Severe (Grade 4) Neutropenia in Cycle 1	0 days Standard Deviation 1.0	4 days Standard Deviation 4.7

PRIMARY outcome

Timeframe: Induction Period. From date of randomization, 21 day treatment cycles up to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days.

Population: Intent-to-treat (ITT) analysis set included all randomized patients. Analysis using the ITT analysis set were conducted on the basis of the randomly assigned treatment.

The occurrence of severe (Grade 4) neutropenia (SN) was a binary variable. If a patient had at least 1 absolute neutrophil count value \<0.5 × 10\^9/L during the Induction Period, the patient was assigned as Yes to the occurrence of SN; otherwise, it was No.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With at Least 1 Occurrence of Severe (Grade 4) Neutropenia	1 Participants	26 Participants

SECONDARY outcome

Timeframe: Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days.

Population: Intent-to-treat (ITT) analysis set included all randomized patients. Analysis using the ITT analysis set were conducted on the basis of the randomly assigned treatment.

Dose reductions are not permitted for trilaciclib or atezolizumab. Dose reductions for E/P are derived from changes in the protocol-specified dose on the dosing page and correspond to the reductions for toxicity specified in the protocol. No more than 2 dose reductions of E/P in total were allowed for any patient. Simultaneous reduction in the doses of etoposide and carboplatin were counted as 1 dose reduction.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
All-Cause Dose Reductions	0.021 Events/Cycle	0.085 Events/Cycle

SECONDARY outcome

Population: Intent-to-treat (ITT) analysis set included all randomized patients. Analysis using the ITT analysis set were conducted on the basis of the randomly assigned treatment.

For this endpoint, the occurrence during the Induction Period was defined as a binary variable (Yes or No); Yes, if total number of events ≥1 was observed, No for other scenarios. If a patient did not have an event, a value of 0 was assigned to that patient. Each red blood cell transfusion with a unique start date on/after Week 5 on study during the Induction was defined as a separate event.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With at Least 1 Occurrence of RBC Transfusion on/After Week 5 (Proportion of Patients)	7 Participants	11 Participants

SECONDARY outcome

Population: Intent-to-treat (ITT) analysis set included all randomized patients. Analysis using the ITT analysis set were conducted on the basis of the randomly assigned treatment.

For this endpoint, the occurrence during the Induction Period was defined as a binary variable (Yes or No); Yes, if total number of events ≥1 was observed, No for other scenarios. If a patient did not have an event, a value of 0 was assigned to that patient. Any G-CSF administration in a cycle during the Induction Period was defined as a separate event. A patient with at least 1 cycle with G-CSF administration during an induction cycle or the Induction Period was considered to have occurrence of G-CSF administration.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Occurrence of Granulocyte Colony-Stimulating Factor (G-CSF) Administration (Proportion of Patients)	16 Participants	25 Participants

SECONDARY outcome

Timeframe: From date of randomization to date of death due to any cause, assessed up to a maximum of 38.1 months.

Population: Intent-to-treat (ITT Analysis Set)

Overall survival was calculated as the time (months) from date of randomization to the date of death due to any cause. Patients who did not die during the study were censored at the date last known to be alive. Patients lacking data beyond the date of randomization had their survival time censored at date of randomization. Overall survival was not censored if a patient received other anti-tumor treatments after the study drugs. Overall survival was calculated using the Kaplan-Meier method.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Overall Survival (OS) 25%	7.2 Months Interval 4.9 to 10.2	6.7 Months Interval 3.6 to 8.1
Overall Survival (OS) Median	12.0 Months Interval 9.6 to 16.2	12.8 Months Interval 7.9 to 15.5
Overall Survival (OS) 75%	20.6 Months Interval 14.5 to 23.2	22.4 Months Interval 15.5 to 30.0

SECONDARY outcome

Population: Intent-to-treat (ITT) analysis set included all randomized patients. Analysis using the ITT analysis set were conducted on the basis of the randomly assigned treatment.

The composite endpoint "major adverse hematologic events" (MAHE) included the following aspects of myelosuppression: All-cause hospitalizations - Each recorded preferred term (PT) with a unique start date was counted as an event. All-cause dose reductions - Dose reductions were permitted for E/P but not for trilaciclib or atezolizumab. No more than 2 dose reductions were allowed. Each dose reduction was counted as a separate event. Febrile neutropenia-Each febrile neutropenia event with a unique start date during the Induction Period was defined as a separate event. Prolonged severe neutropenia (SN)-Each cycle with a severe neutropenia duration greater than 5 days was counted as an event, with the date of the first Grade 4 laboratory value defined as the start date for the time-to-first event analysis. Red blood cell (RBC) transfusion on/after Week 5-Each RBC transfusion with a unique start date on/after Week 5 on study during the Induction Period was defined as a separate event.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Major Adverse Hematologic Events (MAHE) (Composite Endpoint) Major adverse hematologic events (MAHE)	0.132 event rate per week	0.058 event rate per week
Major Adverse Hematologic Events (MAHE) (Composite Endpoint) All-cause hospitalizations	0.032 event rate per week	0.030 event rate per week
Major Adverse Hematologic Events (MAHE) (Composite Endpoint) All-cause dose reductions	0.021 event rate per week	0.085 event rate per week
Major Adverse Hematologic Events (MAHE) (Composite Endpoint) Febrile neutropenia TEAEs	0.002 event rate per week	0.004 event rate per week
Major Adverse Hematologic Events (MAHE) (Composite Endpoint) RBC transfusions on/after Week 5	0.017 event rate per week	0.026 event rate per week
Major Adverse Hematologic Events (MAHE) (Composite Endpoint) Prolonged SN (>5 days)	0.005 event rate per week	0.170 event rate per week

SECONDARY outcome

Timeframe: From date of randomization, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 724 days.

Population: Response Evaluable Analysis Set

For all patients, the Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.1) tumor response data were used to determine each patient's visit response (TPR = time point response). Per RECIST v1.1 for target lesions and assessed by CT/MRI: Complete Response (CR), Disappearance of all target lesions; Partial Response (PR), \>=30% decrease in the sum of the longest diameters of target lesions; Progressive Disease (PD), \>=20% increase in the sum of the longest diameter of target lesions, Stable Disease, neither sufficient shrinkage or increase to quality for PR or PD. Objective Response Rate (ORR) = CR + PR. The TPR at each visit was determined in 2 ways: (1) derived programmatically at the time of analysis using the information from target lesions, non-target lesions, and new lesions based on data collected through eCRF; and (2) judged by the investigator as collected in the eCRF. Results shown here are from the programmatically derived assessments.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=50 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Best Overall Response Complete Response (CR)	0 Participants	1 Participants
Best Overall Response Partial Response (PR)	28 Participants	32 Participants
Best Overall Response Stable Disease (SD)	20 Participants	14 Participants
Best Overall Response Progressive Disease (PD)	2 Participants	2 Participants
Best Overall Response Not Evaluable (NE)	0 Participants	2 Participants
Best Overall Response Missing	0 Participants	1 Participants
Best Overall Response Objective response rate (CR+PR)	28 Participants	33 Participants

SECONDARY outcome

Population: Response Evaluable Analysis Set

Duration of Response (DOR) is the time between first response by RECIST Version 1.1 of CR or PR and the first date that progressive disease is documented by RECIST Version 1.1, or death. Patients who do not experience PD or death will be censored at the last tumor assessment date. Only those patients with confirmed responses will be included in this analysis.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=28 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=33 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Duration of Objective Response (Complete Response or Partial Response) 25%	4.4 months Interval 2.9 to 4.7	3.0 months Interval 2.7 to 4.1
Duration of Objective Response (Complete Response or Partial Response) Median	5.6 months Interval 4.4 to 7.0	4.3 months Interval 3.4 to 4.7
Duration of Objective Response (Complete Response or Partial Response) 75%	8.3 months Interval 5.8 to 13.2	5.0 months Interval 4.6 to 10.5

SECONDARY outcome

Population: Intent-to-treat

Progression-free survival (PFS) was defined as the time (number of months) from date of randomization until date of documented radiologic disease progression per RECIST v1.1 or death due to any cause, whichever came first.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Progression-Free Survival 25%	3.7 months Interval 2.7 to 4.2	4.0 months Interval 3.1 to 4.3
Progression-Free Survival Median	5.9 months Interval 4.2 to 7.1	5.4 months Interval 4.3 to 5.7
Progression-Free Survival 75%	8.5 months Interval 7.1 to 10.4	6.4 months Interval 5.7 to 8.9

SECONDARY outcome

Population: Intent-to-treat (ITT Analysis Set)

The criterion for identifying febrile neutropenia was if the preferred term for an adverse event was "FEBRILE NEUTROPENIA." Any occurrence of a febrile neutropenia event during the induction treatment period is defined as a binary variable (Yes or No); Yes if total number of febrile neutropenia events ≥ 1 is observed, No for other scenarios. Each febrile neutropenia event with a unique start date during the induction treatment period was defined as a separate event.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With at Least 1 Occurrence of Febrile Neutropenia	1 Participants	3 Participants

SECONDARY outcome

Population: Intent-to-treat

The occurrence of Grade 3 and 4 hematologic toxicities was a binary endpoint. If a patient had at least 1 cycle with at least 1 Grade 3 or 4 hematologic toxicities during the Induction Period, the patient was assigned as "Yes" to the occurrence of Grade 3 and 4 hematologic toxicities; otherwise, it was "No". If a patient did not have an event, the value of 0 was assigned to that patient.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With at Least 1 Occurrence of Grade 3 or 4 Hematologic Laboratory Abnormalities	23 Participants	43 Participants

SECONDARY outcome

Population: Intent-to-treat

Any ESA administration in a cycle during the Induction Period was defined as a separate event. A patient with at least 1 cycle with ESA administration during an induction cycle or the Induction Period was considered to have occurrence of ESA administration. The criterion to select proper records was as follows: If the chemical subgroup from WHO-DD Version September 2017 (ie TEXT4 for CODE4) takes the value "OTHER ANTIANEMIC PREPARATIONS," the medication was classified as ESAs.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With at Least 1 Occurrence of Erythropoiesis Stimulating Agent (ESA) Administration	3 Participants	6 Participants

SECONDARY outcome

Population: Intent-to-treat

Any occurrence of a platelet transfusion during the induction treatment period was defined as a binary variable (Yes or No); Yes if total number of febrile neutropenia events ≥ 1 is observed, No for other scenarios. If the patient did not have an event, the value of 0 was assigned to that patient. Each platelet transfusion event with a unique start date during the induction treatment period was defined as a separate event.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With at Least 1 Occurrence of Platelet Transfusion	1 Participants	2 Participants

SECONDARY outcome

Population: Intent-to-treat

Any occurrence of an infection SAE during the induction treatment period was defined as a binary variable (Yes or No); Yes if total number of febrile neutropenia events ≥ 1 is observed, No for other scenarios. If the patient did not have an event, the value of 0 was assigned to that patient. The criterion for identifying the proper infection SAE records was as follows: if the system organ class (SOC) from Medical Dictionary for Regulatory Activities (MedDRA) Version 20.1 takes value "INFECTIONS AND INFESTATIONS," and the AE was a serious event.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With at Least 1 Occurrence of Infection Serious Adverse Events (SAEs)	3 Participants	7 Participants

SECONDARY outcome

Population: Intent-to-treat

Any occurrence of a pulmonary SAE during the induction treatment period was defined as a binary variable (Yes or No); Yes if total number of febrile neutropenia events ≥ 1 is observed, No for other scenarios. If the patient did not have an event, the value of 0 was assigned to that patient. Each pulmonary infection SAE with a unique start date during the induction treatment period was defined as separate event. The criterion for identifying the proper pulmonary infection SAE records was as follows: The SOC from MedDRA Version 20.1 took the value "INFECTIONS AND INFESTATIONS," the adverse event was a serious event, and the PT took values from the following list of PTs under the category of pulmonary infection adverse events: bronchiolitis, bronchitis, infectious pleural effusion, influenza, pneumonia, pneumonia bacterial, respiratory tract infection, upper respiratory tract infection, and viral upper respiratory tract infection.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With at Least 1 Occurrence of Pulmonary Infection Serious Adverse Events (SAEs)	2 Participants	5 Participants

SECONDARY outcome

Population: Intent-to-treat

Occurrence of an IV antibiotics administration during the induction treatment period is defined as a binary variable (Yes or No); Yes if total number of IV antibiotics administration ≥ 1 is observed, No for other scenarios. Each IV antibiotic with a unique start date during the induction treatment period will be defined as a separate event. The criteria for identifying an IV antibiotic administration event was (1) if the therapeutic subgroup from WHO-DD Version September 2017 (ie, TEXT2 for CODE2) takes the value "ANTIBACTERIALS FOR SYSTEMIC USE," and (2) the route of medication was "intravenous" or the route was "other" with the detailed specification as "IVPB."

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=54 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With at Least 1 Occurrence of IV Antibiotic Uses	10 Participants	12 Participants

SECONDARY outcome

Timeframe: From date of first dose, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 1162 days.

Population: Safety analysis

Induction period duration of exposure (days) = Day 1 of last induction cycle - Cycle 1 Day 1 of induction phase + 21. Maintenance period duration of exposure (days) = Day 1 of the last maintenance cycle -Cycle 1 Day 1 of maintenance phase + 21.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Duration of Study Drug Exposure (Induction Period and Maintenance Period) Induction Period	83 Days Standard Deviation 15.6	88 Days Standard Deviation 20.5
Duration of Study Drug Exposure (Induction Period and Maintenance Period) Maintenance Period	223 Days Standard Deviation 253.3	232 Days Standard Deviation 271.0

SECONDARY outcome

Population: Safety analysis

Patients were considered to have started a cycle if they have received at least one dose of any study drug (carboplatin, etoposide, atezolizumab or trilaciclib).

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Cycles Completed (Induction Period and Maintenance Period) Maintenance Period	10 Cycles Standard Deviation 11.9	10 Cycles Standard Deviation 11.3
Number of Cycles Completed (Induction Period and Maintenance Period) Induction Period	4 Cycles Standard Deviation 0.6	4 Cycles Standard Deviation 0.8

SECONDARY outcome

Population: Safety Analysis

Relative dose intensity is defined as 100% times the actual dose intensity divided by the planned dose intensity. The planned dose intensity is defined as the cumulative planned dose through the study divided by (number of cycles \* 3 weeks)

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Relative Dose Intensity of Trilaciclib/Placebo, Carboplatin, Etoposide, Atezolizumab (Induction Period) and Atezolizumab (Maintenance Period) Trilaciclib/Placebo	94.6 percentage of dose Standard Deviation 7.65	91.1 percentage of dose Standard Deviation 10.68
Relative Dose Intensity of Trilaciclib/Placebo, Carboplatin, Etoposide, Atezolizumab (Induction Period) and Atezolizumab (Maintenance Period) Carboplatin	95.3 percentage of dose Standard Deviation 7.65	89.1 percentage of dose Standard Deviation 12.25
Relative Dose Intensity of Trilaciclib/Placebo, Carboplatin, Etoposide, Atezolizumab (Induction Period) and Atezolizumab (Maintenance Period) Etoposide	93.4 percentage of dose Standard Deviation 9.59	87.7 percentage of dose Standard Deviation 13.92
Relative Dose Intensity of Trilaciclib/Placebo, Carboplatin, Etoposide, Atezolizumab (Induction Period) and Atezolizumab (Maintenance Period) Atezolizumab (Induction)	94.1 percentage of dose Standard Deviation 9.54	91.0 percentage of dose Standard Deviation 11.26
Relative Dose Intensity of Trilaciclib/Placebo, Carboplatin, Etoposide, Atezolizumab (Induction Period) and Atezolizumab (Maintenance Period) Atezolizumab (Maintenance)	93.5 percentage of dose Standard Deviation 11.45	94.2 percentage of dose Standard Deviation 10.19

SECONDARY outcome

Timeframe: Induction Period. From date of first dose, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days.

Population: Safety analysis

After Cycle 1, patients need to meet pre-specified laboratory parameter criteria before initiating Cycle 2 and each subsequent cycle of chemotherapy. A "Cycle Day Status" page asks if the cycle was delayed. If the start of the current cycle was delayed (the site answers "Yes"), this will be counted as a delay. Cycle delays could occur for management of toxicity (hematologic or non-hematologic) or for administrative/logistic reasons. The reason for each cycle delay was captured in the eCRF if it was related to AEs. Reasons other than AEs were not captured.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Induction Period) Number of patients with any cycle delays	18 Participants	31 Participants
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Induction Period) 0 cycles	34 Participants	22 Participants
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Induction Period) 1 cycle	14 Participants	18 Participants
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Induction Period) 2 cycles	2 Participants	10 Participants
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Induction Period) 3 or more cycles	2 Participants	3 Participants

SECONDARY outcome

Timeframe: Maintenance Period. From date of first maintenance dose, 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 1160 days.

Population: Safety analysis

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Maintenance Period) Number of patients with any cycle delays	21 Participants	26 Participants
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Maintenance Period) 0 cycles	20 Participants	21 Participants
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Maintenance Period) 1 cycle	10 Participants	12 Participants
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Maintenance Period) 2 cycles	6 Participants	6 Participants
Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Maintenance Period) 3 or more cycles	5 Participants	8 Participants

SECONDARY outcome

Population: Safety analysis

Missed doses are identified on the dosing page of each study drug based on the question "Was the dose given?". The missed dose information will be obtained for each study drug. For a study drug, if the last record of response to question "Was the dose given?" is No, it will not be considered as a missed dose but instead considered to be end of treatment if both criteria below are met: (1) No other study drugs are given on the same day, and (2) No study drugs are given subsequently.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With Any Missed Doses [for Each Study Drug: Trilaciclib/Placebo, Carboplatin and Etoposide] (Induction Period) Trilaciclib/Placebo	3 Participants	0 Participants
Number of Participants With Any Missed Doses [for Each Study Drug: Trilaciclib/Placebo, Carboplatin and Etoposide] (Induction Period) Carboplatin	1 Participants	0 Participants
Number of Participants With Any Missed Doses [for Each Study Drug: Trilaciclib/Placebo, Carboplatin and Etoposide] (Induction Period) Etoposide	3 Participants	0 Participants

SECONDARY outcome

Population: Safety analysis

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With Any Missed Doses of Atezolizumab (Overall Treatment Period)	3 Participants	3 Participants

SECONDARY outcome

Population: Safety analysis

Dose interruptions were defined as interruption of infusion, regardless of whether the study drug was continued after the interruption.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With Any Dose Interruptions [for Each Study Drug: Trilaciclib/Placebo, Carboplatin and Etoposide] (Induction Period) Trilaciclib/placebo	3 Participants	0 Participants
Number of Participants With Any Dose Interruptions [for Each Study Drug: Trilaciclib/Placebo, Carboplatin and Etoposide] (Induction Period) Carboplatin	0 Participants	1 Participants
Number of Participants With Any Dose Interruptions [for Each Study Drug: Trilaciclib/Placebo, Carboplatin and Etoposide] (Induction Period) Etoposide	2 Participants	3 Participants

SECONDARY outcome

Population: Safety analysis

Dose interruptions were defined as interruption of infusion, regardless of whether the study drug was continued after the interruption.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With Any Interrupted Doses of Atezolizumab (Overall Treatment Period)	1 Participants	0 Participants

SECONDARY outcome

Population: Safety analysis

No dose reductions were allowed for trilaciclib or atezolizumab during the study.

Outcome measures

Outcome measures
Measure	Trilaciclib+Etoposide/Carboplatin/Atezolizumab n=52 Participants Induction: Patients received trilaciclib 240 mg/m² administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.	Placebo+Etoposide/Carboplatin/Atezolizumab n=53 Participants Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity, or discontinuation by the patient or investigator.
Number of Participants With Any Dose Reductions of Carboplatin and Etoposide (Induction Period) Etoposide	3 Participants	14 Participants
Number of Participants With Any Dose Reductions of Carboplatin and Etoposide (Induction Period) Carboplatin	1 Participants	13 Participants

Adverse Events

Trilaciclib+Etoposide/Carboplatin/Atezolizumab

Serious events: 17 serious events

Other events: 49 other events

Deaths: 42 deaths

Placebo+Etoposide/Carboplatin/Atezolizumab

Serious events: 25 serious events

Other events: 52 other events

Deaths: 44 deaths

Serious adverse events

Other adverse events

Additional Information

Clinical Trial Info.

G1 Therapeutics, Inc.

Phone: 919-213-9835

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Restriction type: OTHER