Trial Outcomes & Findings for Study of Vibostolimab Alone and in Combination With Pembrolizumab in Advanced Solid Tumors (MK-7684-001) ( KEYVIBE-001) (NCT NCT02964013)

Last Updated: 2025-10-14

Results Overview

A DLT is defined as an event with toxicity including the type, severity, time of onset, time of resolution, and the probable association with study treatment that are not due to pre-existing conditions as defined by the Common Terminology Criteria for Adverse Events Version 4.0 (CTCAE4.0).

Recruitment status

COMPLETED

Study phase

PHASE1

Target enrollment

474 participants

Primary outcome timeframe

Up to 24 Months

Results posted on

2025-10-14

Participant Flow

Participants at least 18 years of age with advanced solid tumors were enrolled in this study.

As it was pre-specified to assign treatment groups irrespective of dose level, or cohorts such as based on type of cancer or country of origin, participants were instead combined into treatment groups based on their unique combination of interventions. For dose escalation, it was pre-specifed that participants were combined into monotherapy or sequential treatment groups rather than separate dose levels. Parts A and B were conducted at the same time, not sequentially.

Participant milestones

Participant milestones
Measure	Vibostolimab During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
Overall Study STARTED	68	295	60	11	40
Overall Study Treated	68	293	60	10	40
Overall Study Crossed Over	25	0	0	0	0
Overall Study COMPLETED	0	0	0	0	0
Overall Study NOT COMPLETED	68	295	60	11	40

Reasons for withdrawal

Reasons for withdrawal
Measure	Vibostolimab During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
Overall Study Death	58	239	38	10	33
Overall Study Lost to Follow-up	1	4	2	0	0
Overall Study Physician Decision	0	1	0	0	0
Overall Study Sponsor Decision	3	22	11	0	7
Overall Study Withdrawal by Subject	6	27	9	0	0
Overall Study Not Treated	0	2	0	1	0

Baseline Characteristics

Study of Vibostolimab Alone and in Combination With Pembrolizumab in Advanced Solid Tumors (MK-7684-001) ( KEYVIBE-001)

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Vibostolimab n=68 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab n=293 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) n=60 Participants Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin n=10 Participants Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide n=40 Participants Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.	Total n=471 Participants Total of all reporting groups
Age, Continuous	63.1 Years STANDARD_DEVIATION 12.0 • n=5 Participants	57.6 Years STANDARD_DEVIATION 12.0 • n=7 Participants	58.5 Years STANDARD_DEVIATION 10.0 • n=5 Participants	68.5 Years STANDARD_DEVIATION 9.0 • n=4 Participants	66.2 Years STANDARD_DEVIATION 8.2 • n=21 Participants	59.3 Years STANDARD_DEVIATION 12.0 • n=8 Participants
Sex: Female, Male Female	34 Participants n=5 Participants	190 Participants n=7 Participants	43 Participants n=5 Participants	5 Participants n=4 Participants	10 Participants n=21 Participants	282 Participants n=8 Participants
Sex: Female, Male Male	34 Participants n=5 Participants	103 Participants n=7 Participants	17 Participants n=5 Participants	5 Participants n=4 Participants	30 Participants n=21 Participants	189 Participants n=8 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	7 Participants n=5 Participants	17 Participants n=7 Participants	1 Participants n=5 Participants	0 Participants n=4 Participants	2 Participants n=21 Participants	27 Participants n=8 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	59 Participants n=5 Participants	268 Participants n=7 Participants	57 Participants n=5 Participants	9 Participants n=4 Participants	37 Participants n=21 Participants	430 Participants n=8 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	2 Participants n=5 Participants	8 Participants n=7 Participants	2 Participants n=5 Participants	1 Participants n=4 Participants	1 Participants n=21 Participants	14 Participants n=8 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants	0 Participants n=8 Participants
Race (NIH/OMB) Asian	13 Participants n=5 Participants	99 Participants n=7 Participants	25 Participants n=5 Participants	5 Participants n=4 Participants	27 Participants n=21 Participants	169 Participants n=8 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants	0 Participants n=8 Participants
Race (NIH/OMB) Black or African American	7 Participants n=5 Participants	8 Participants n=7 Participants	1 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants	16 Participants n=8 Participants
Race (NIH/OMB) White	48 Participants n=5 Participants	181 Participants n=7 Participants	34 Participants n=5 Participants	5 Participants n=4 Participants	12 Participants n=21 Participants	280 Participants n=8 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants	0 Participants n=8 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	5 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	1 Participants n=21 Participants	6 Participants n=8 Participants

PRIMARY outcome

Timeframe: Up to 24 Months

Population: The population analyzed was treated participants. Per protocol, participants were assigned to a treatment group based on their unique combination of interventions. Hence for dose escalation, participants were assigned. to either monotherapy or sequential treatment groups rather than by dosage levels.

Outcome measures

Outcome measures
Measure	Vibostolimab n=68 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab n=293 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Vibostolimab + Pembrolizumab After Crossover n=25 Participants After discontinuing vibostolimab monotherapy due to progressive disease participants who crossed over to vibostolimab + pembrolizumab as sequential administration.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) n=60 Participants Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin n=10 Participants Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide n=40 Participants Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
Number of Participants With Dose Limiting Toxicities (DLTs) up to 24 Months	0 Participants	0 Participants	0 Participants	0 Participants	1 Participants	0 Participants

PRIMARY outcome

Timeframe: Up to 28 Months

An AE is defined as any untoward medical occurrence in a participant or clinical investigation subject administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An adverse event can therefore be any unfavourable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a medicinal product or protocol specified procedure, whether or not considered related to the medicinal product or protocol specified procedure. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an adverse event.

Outcome measures

Outcome measures
Measure	Vibostolimab n=68 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab n=293 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Vibostolimab + Pembrolizumab After Crossover n=25 Participants After discontinuing vibostolimab monotherapy due to progressive disease participants who crossed over to vibostolimab + pembrolizumab as sequential administration.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) n=60 Participants Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin n=10 Participants Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide n=40 Participants Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
Number of Participants Who Experienced At Least One Adverse Event (AE)	67 Participants	284 Participants	24 Participants	60 Participants	10 Participants	40 Participants

PRIMARY outcome

Timeframe: Up to 24 Months

Outcome measures

Outcome measures
Measure	Vibostolimab n=68 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab n=293 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Vibostolimab + Pembrolizumab After Crossover n=25 Participants After discontinuing vibostolimab monotherapy due to progressive disease participants who crossed over to vibostolimab + pembrolizumab as sequential administration.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) n=60 Participants Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin n=10 Participants Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide n=40 Participants Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
Number of Participants Who Discontinued Study Treatment Due to an AE	2 Participants	30 Participants	1 Participants	4 Participants	1 Participants	3 Participants

SECONDARY outcome

Timeframe: Up to 24 Months

Population: Participants with a baseline scan with measurable disease by investigator assessment who were administered a dose of study treatment regardless of dose level. Only dose escalation treatment groups were analyzed, who were assigned based on their combination of interventions rather than by dosage levels.

ORR is the percentage of participants who experience complete response (CR: disappearance of all target lesions) or partial response (PR: at least a 30% decrease in the sum of diameters of target lesions) at any time during the trial using RECIST, version 1.1 as assessed by investigator review. Results for participants treated with vibostolimab dose escalation are presented.

Outcome measures

Outcome measures
Measure	Vibostolimab n=34 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab n=42 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Vibostolimab + Pembrolizumab After Crossover After discontinuing vibostolimab monotherapy due to progressive disease participants who crossed over to vibostolimab + pembrolizumab as sequential administration.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
Overall Response Rate (ORR) in Participants in Vibostolimab Dose Escalation Phase Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1)	0.0 Percentage of participants Interval 0.0 to 10.3	7.1 Percentage of participants Interval 1.5 to 19.5	—	—	—	—

SECONDARY outcome

Timeframe: Up to 24 Months

Population: Participants with a baseline scan with measurable disease by investigator assessment who were administered a dose of study treatment regardless of dose level. Both dose escalation and expansion phases were analyzed, assigned to treatment groups based on their combination of interventions rather than by dosage levels.

ORR is the percentage of participants who experience complete response (CR: disappearance of all target lesions) or partial response (PR: at least a 30% decrease in the sum of diameters of target lesions) at any time during the trial using RECIST, version 1.1 as assessed by investigator review. Results for participants with PD-1 refractory NSCLC treated with 200 or 210 mg vibostolimab in dose escalation as well as dose expansion phases are presented.

Outcome measures

Outcome measures
Measure	Vibostolimab n=41 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab n=38 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Vibostolimab + Pembrolizumab After Crossover After discontinuing vibostolimab monotherapy due to progressive disease participants who crossed over to vibostolimab + pembrolizumab as sequential administration.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
ORR in Participants With Programmed Death 1 (PD-1) Refractory Non-small Cell Lung Cancer (NSCLC) Per RECIST 1.1	2.4 Percentage of participants Interval 0.1 to 12.9	5.3 Percentage of participants Interval 0.6 to 17.7	—	—	—	—

SECONDARY outcome

Timeframe: Up to 24 Months

Population: Participants with a baseline scan with measurable disease by investigator assessment who were administered a dose of study treatment regardless of dose level. Both dose escalation and expansion phases were analyzed assigned to treatment groups based on their combination of interventions rather than by dosage levels.

ORR is the percentage of participants who experience complete response (CR: disappearance of all target lesions) or partial response (PR: at least a 30% decrease in the sum of diameters of target lesions) at any time during the trial using RECIST, version 1.1 as assessed by investigator review. Results for participants with PD-1 naive NSCLC treated with pembrolizumab and 200 mg vibostolimab from both the dose escalation and expansion phases are presented.

Outcome measures

Outcome measures
Measure	Vibostolimab During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab n=41 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Vibostolimab + Pembrolizumab After Crossover After discontinuing vibostolimab monotherapy due to progressive disease participants who crossed over to vibostolimab + pembrolizumab as sequential administration.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
ORR in Participants With PD-1 Naive NSCLC Per RECIST 1.1	—	24.4 Percentage of participants Interval 12.4 to 40.3	—	—	—	—

SECONDARY outcome

Timeframe: Up to 24 Months

Population: Participants with a baseline scan with measurable disease by investigator assessment who were administered a dose of study treatment regardless of dose level. For ES-SCLC only participants in the etoposide treatment group were analyzed, based on their combination of interventions rather than by dosage levels.

ORR is the percentage of participants who experience complete response (CR: disappearance of all target lesions) or partial response (PR: at least a 30% decrease in the sum of diameters of target lesions) at any time during the trial using RECIST, version 1.1 as assessed by investigator review. Participants with ES-SCLC treated with vibostolimab in combination with pembrolizumab, carboplatin or cisplatin, and etoposide were analyzed.

Outcome measures

Outcome measures
Measure	Vibostolimab During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Vibostolimab + Pembrolizumab After Crossover After discontinuing vibostolimab monotherapy due to progressive disease participants who crossed over to vibostolimab + pembrolizumab as sequential administration.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide n=40 Participants Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
ORR in Participants With Extensive-stage Small Cell Lung Cancer (ES-SCLC) Per RECIST 1.1	—	—	—	—	—	75.0 Percentage of participants Interval 58.8 to 87.3

SECONDARY outcome

Timeframe: Up to 24 Months

Population: Participants with a baseline scan with measurable disease by investigator assessment who were administered a dose of study treatment regardless of dose level. For PD-1 naive ovarian cancer only participants treated with vibostolimab and pembrolizumab taken sequentially, or as a coformulation were analyzed.

ORR is the percentage of participants who experience complete response (CR: disappearance of all target lesions) or partial response (PR: at least a 30% decrease in the sum of diameters of target lesions) at any time during the trial using RECIST, version 1.1 as assessed by investigator review. Participants with PD-1 naive ovarian cancer treated with pembrolizumab and vibostolimab dose escalation or MK-7984A were analyzed.

Outcome measures

Outcome measures
Measure	Vibostolimab During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab n=21 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Vibostolimab + Pembrolizumab After Crossover After discontinuing vibostolimab monotherapy due to progressive disease participants who crossed over to vibostolimab + pembrolizumab as sequential administration.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) n=40 Participants Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
ORR in Participants With PD-1 Naive Ovarian Cancer Per RECIST 1.1	—	9.5 Percentage of participants Interval 1.2 to 30.4	—	7.5 Percentage of participants Interval 1.6 to 20.4	—	—

SECONDARY outcome

Timeframe: Up to 24 Months

Population: Participants with a baseline scan with measurable disease by investigator assessment who were administered a dose of study treatment regardless of dose level. For PD-1 naive cervical cancer only participants treated with vibostolimab and pembrolizumab sequentially were analyzed.

ORR is the percentage of participants who experience complete response (CR: disappearance of all target lesions) or partial response (PR: at least a 30% decrease in the sum of diameters of target lesions) at any time during the trial using RECIST, version 1.1 as assessed by investigator review. Results for participants with PD-1 naive cervical cancer treated with pembrolizumab and either 200 mg or 700 mg vibostolimab are presented.

Outcome measures

Outcome measures
Measure	Vibostolimab During an initial dose evaluation phase, participants received various doses of vibostolimab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the recommended Phase 2 dose (RPTD) of 200 mg was established based on the number of dose limiting toxicities (DLTs) at each dose level. Participants continued receiving 200 mg vibostolimab on Day 1 of each 21-day infusion cycle until the 35-cycle limit is reached.	Vibostolimab + Pembrolizumab n=41 Participants During an initial dose evaluation phase, participants received various doses of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle (for a maximum of 35 cycles) until the RPTD of vibostolimab of 200 mg was established based on the number of DLTs at each dose level. Participants continued receiving 200 mg of vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day infusion cycle until the 35-cycle limit was reached.	Vibostolimab + Pembrolizumab After Crossover After discontinuing vibostolimab monotherapy due to progressive disease participants who crossed over to vibostolimab + pembrolizumab as sequential administration.	Pembrolizumab/Vibostolimab Coformulation (MK-7684A) Participants received a fixed dose of pembrolizumab/vibostolimab coformulation, consisting of 200 mg of pembrolizumab + 200 mg vibostolimab, on Day 1 of each 21-day infusion cycle for up to 35 cycles.	Vibostolimab +Pembrolizumab+Pemetrexed+Carboplatin Participants received a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab, 500 mg/m\^2 pemetrexed, and Area Under Curve (AUC) 5 mg/mL/min carboplatin on Day 1 of each 21-day infusion cycle for up to 4 cycles followed by maintenance therapy with a 200 mg dose of vibostolimab in combination with 200 mg pembrolizumab and 500 mg/m\^2 pemetrexed on Day 1 of each 21-day infusion cycle for up to an additional 31 cycles.	Vibostolimab+Pembrolizumab+Carboplatin OR Cisplatin+Etoposide Participants received 200 mg vibostolimab in combination with 200 mg pembrolizumab, plus the investigator's choice of Area Under Curve (AUC) 5 mg/mL/min carboplatin OR 75 mg/m\^2 cisplatin on Day 1 of each 21-day cycle plus 100 mg/m\^2/day etoposide on Days 1-3 of each 21-day cycle for up to 4 cycles. Maintenance therapy with 200 mg vibostolimab in combination with 200 mg pembrolizumab on Day 1 of each 21-day cycle will continue for up to an additional 31 cycles. A participant will be allowed to switch from cisplatin to carboplatin in the event of an adverse event (AE), ineligibility for further cisplatin therapy, and/or the investigator considers switching to carboplatin to be in the best interest of the participant.
ORR in Participants With PD-1 Naive Cervical Cancer Per RECIST 1.1 Vibostolimab 200 mg	—	14.6 Percentage of participants Interval 5.6 to 29.2	—	—	—	—
ORR in Participants With PD-1 Naive Cervical Cancer Per RECIST 1.1 Vibostolimab 700 mg	—	23.1 Percentage of participants Interval 11.1 to 39.3	—	—	—	—

SECONDARY outcome

Timeframe: Cycle 1, Cycle 4: Day 1 pre-dose, 0.5, and 2 hours post-dose; once daily on Days 2, 3, 5, 8, 15 and 22.

Population: Participants who complied with the protocol sufficiently to ensure that the data they generated will be likely to exhibit the effects of treatment, according to the underlying scientific model. Compliance covers such considerations as exposure to treatment, availability of measurements, and absence of major protocol violations. Only participants with dose escalation were analyzed.

Blood samples were collected from participants during cycle 1 and cycle 4 of treatment (Cycle length is 21 days) in order to determine the AUC 0-21 days of plasma vibostolimab, Only results from participants treated with increasing amounts of vibostolimab monotherapy or vibostolimab combined with 200 mg pembrolizumab are presented; whereas other treatment groups were not analyzed. Due to terminal fitting issue, non-calculable AUC0-21 days was replaced with AUClast for a few participants.