Trial Outcomes & Findings for Abiraterone With Discontinuation of Gonadotropin-Releasing Hormone Analogues in Metastatic Prostate Cancer (NCT NCT03565835)

Results Overview

The number/percentage of patients with a castrate serum testosterone level, defined as having a serum castrate concentration \<50 ng/dL when Abiraterone acetate plus prednisone (AAP) is used without GnRH analogues in metastatic prostate cancer, will be determined. Results are summarized as a number/percentage of participants.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

31 participants

Primary outcome timeframe

Approximately 24 weeks

Results posted on

2026-01-26

Participant Flow

35 participants signed informed consent forms to participate in the study. Three participants failed to meet eligibility criteria and were excluded from the protocol and one participant opted not to participate. As a result, 31 participants were enrolled into the study.

Participant milestones

Participant milestones
Measure	Abiraterone and Prednisone Without a GnRH Analogue Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of Gonadotropin-releasing hormone (GnRH) Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Overall Study STARTED	31
Overall Study COMPLETED	27
Overall Study NOT COMPLETED	4

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Abiraterone With Discontinuation of Gonadotropin-Releasing Hormone Analogues in Metastatic Prostate Cancer

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=31 Participants Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Age, Continuous	69 years n=25 Participants
Sex: Female, Male Female	0 Participants n=25 Participants
Sex: Female, Male Male	31 Participants n=25 Participants
Race/Ethnicity, Customized non-Hispanic Black or African-American	21 Participants n=25 Participants
Race/Ethnicity, Customized Hispanic or Latino	10 Participants n=25 Participants
Region of Enrollment United States	31 participants n=25 Participants
Castration-resistant disease as AAP (Abiraterone acetate plus prednisone) indication	16 Participants n=25 Participants
Duration of Androgen deprivation therapy (ADT) prior to enrollment	29.1 months n=25 Participants
Duration of Abiraterone acetate plus Prednisone (AAP) prior to enrollment	9.2 months n=25 Participants

PRIMARY outcome

Timeframe: Approximately 24 weeks

Population: 27 of 31 patients were evaluable at \~24 weeks

The number/percentage of patients with a castrate serum testosterone level, defined as having a serum castrate concentration \<50 ng/dL when Abiraterone acetate plus prednisone (AAP) is used without GnRH analogues in metastatic prostate cancer, will be determined. Results are summarized as a number/percentage of participants.

Outcome measures

Outcome measures
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=27 Participants Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Percentage of Patients With Castrate Level of Serum Testosterone	25 Participants

SECONDARY outcome

Timeframe: Baseline and 6 months, 12 months, 18 months, 24 months, and 30 months following initiation of treatment

Population: The number of patients analyzed at each timepoint is summarized in the table below.

Mean serum testosterone (T) concentrations in patients with metastatic prostate cancer treated with abiraterone acetate plus prednisone without a GnRH analogue was measured. Results have been summarized and reported in nanograms/deciliter (ng/dL) using basic descriptive statistics.

Outcome measures

Outcome measures
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=29 Participants Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Serum Testosterone (T) Levels 18 months	8.36 ng/dL Standard Deviation 8.52
Serum Testosterone (T) Levels 24 months	11.07 ng/dL Standard Deviation 18.1
Serum Testosterone (T) Levels 30 months	13 ng/dL Standard Deviation 20.54
Serum Testosterone (T) Levels Baseline	1.52 ng/dL Standard Deviation 3.15
Serum Testosterone (T) Levels 6 months	4.46 ng/dL Standard Deviation 5.1
Serum Testosterone (T) Levels 12 months	7.1 ng/dL Standard Deviation 12.62

SECONDARY outcome

Timeframe: Baseline and 6 months, 12 months, 18 months, 24 months, and 30 months following initiation of treatment

Population: The number of patients analyzed at each timepoint is summarized in the table below.

Mean serum LH levels in patients with metastatic prostate cancer treated with abiraterone acetate plus prednisone without a GnRH analogue was measured. Results have been summarized and reported in International Units/Liter (IU/L) using basic descriptive statistics.

Outcome measures

Outcome measures
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=26 Participants Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Serum Luteinizing Hormone (LH) Levels Baseline	0.83 IU/L Standard Deviation 1.17
Serum Luteinizing Hormone (LH) Levels 6 months	17.98 IU/L Standard Deviation 21.42
Serum Luteinizing Hormone (LH) Levels 12 months	29.49 IU/L Standard Deviation 26.73
Serum Luteinizing Hormone (LH) Levels 18 months	19.32 IU/L Standard Deviation 15.29
Serum Luteinizing Hormone (LH) Levels 24 months	20.55 IU/L Standard Deviation 17.27
Serum Luteinizing Hormone (LH) Levels 30 months	21.48 IU/L Standard Deviation 17.87

SECONDARY outcome

Timeframe: Baseline and 6 months, 12 months, 18 months, 24 months, and 30 months following initiation of treatment

Population: The number of patients analyzed at each timepoint is summarized in the table below.

Mean PSA response in patients with metastatic prostate cancer treated with abiraterone acetate plus prednisone without a GnRH analogue was measured. Results have been summarized and reported in ng/mL using basic descriptive statistics.

Outcome measures

Outcome measures
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=28 Participants Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Prostate-specific Antigen (PSA) Response Baseline	0.75 ng/mL Standard Deviation 1.45
Prostate-specific Antigen (PSA) Response 6 Months	0.75 ng/mL Standard Deviation 1.45
Prostate-specific Antigen (PSA) Response 12 Months	1.6 ng/mL Standard Deviation 2.35
Prostate-specific Antigen (PSA) Response 18 Months	3.2 ng/mL Standard Deviation 5.61
Prostate-specific Antigen (PSA) Response 24 Months	2.54 ng/mL Standard Deviation 3.77
Prostate-specific Antigen (PSA) Response 30 Months	2.31 ng/mL Standard Deviation 2.79

SECONDARY outcome

Timeframe: 24 weeks

The number of patients with treatment-related adverse events due to toxicity which lead to discontinuation from the study at 24 weeks is summarized.

Outcome measures

Outcome measures
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=27 Participants Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Treatment-related Adverse Events Due to Toxicity	0 Participants

SECONDARY outcome

Timeframe: From initiation of treatment to the end of treatment, up to approximately 41 months (~178 weeks)

Population: rPFS data was not available for 1 patient.

The duration of time from trial entry until radiographic progression-free survival will be measured/reported. Progression-free survival is an assessment of the average time a patient lives without disease progression, as detected on radiographic imaging scans, or the patient dies from the disease, whichever comes first. Results have been summarized and reported in weeks using basic descriptive statistics.

Outcome measures

Outcome measures
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=30 Participants Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Radiographic Progression-free Survival (rPFS)	119 weeks Interval 87.1 to An upper bound 95% confidence interval was not able to be reached for rPFS due to censoring at the conclusion of the trial.

SECONDARY outcome

Timeframe: From initiation of treatment until the end of treatment, up to approximately 41 months

Population: OS data was not available for 1 patient.

Overall survival is an assessment of survival from the time initiation of treatment until the time of death to death due to any cause. Results have been summarized and reported in weeks using basic descriptive statistics.

Outcome measures

Outcome measures
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=30 Participants Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Overall Survival (OS)	NA weeks Interval 102.1 to Median OS was not achieved. More than 50% of patients suppressed the censored time of 158 weeks. An upper bound 95% confidence interval was not able to be reached for OS.

POST_HOC outcome

Timeframe: 12 months, 18 months, 24 months, and 30 months following initiation of treatment

Population: The number of patients analyzed at each timepoint is summarized in the table below.

The number/percentage of patients with a castrate serum testosterone level \<50 ng/dL when abiraterone acetate plus prednisone is used without GnRH analogues in metastatic prostate cancer was summarized using basic descriptive statistics.

Outcome measures

Outcome measures
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=26 Participants Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
Percentage of Patients With a Castrate Serum Testosterone Level <50 ng/dL 12 months	22 Participants
Percentage of Patients With a Castrate Serum Testosterone Level <50 ng/dL 18 months	18 Participants
Percentage of Patients With a Castrate Serum Testosterone Level <50 ng/dL 24 months	16 Participants
Percentage of Patients With a Castrate Serum Testosterone Level <50 ng/dL 30 months	11 Participants

Adverse Events

Abiraterone and Prednisone Without a GnRH Analogue

Serious events: 0 serious events

Other events: 16 other events

Deaths: 3 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure	Abiraterone and Prednisone Without a GnRH Analogue n=31 participants at risk Abiraterone (1000 mg daily) with Prednisone (5 mg) with Discontinuation of GnRH Analogue Injection Abiraterone Acetate: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue Prednisone: Abiraterone Acetate with Prednisone and with Discontinuation of GnRH Analogue
General disorders Fatigue	3.2% 1/31 • Adverse events (AEs) will be recorded from the time of consent and for at least 30 days after treatment discontinuation, up to 41 months.
Vascular disorders Hot Flashes	16.1% 5/31 • Adverse events (AEs) will be recorded from the time of consent and for at least 30 days after treatment discontinuation, up to 41 months.
Metabolism and nutrition disorders Hypokalemia	6.5% 2/31 • Adverse events (AEs) will be recorded from the time of consent and for at least 30 days after treatment discontinuation, up to 41 months.
Reproductive system and breast disorders Prostatic Obstruction	3.2% 1/31 • Adverse events (AEs) will be recorded from the time of consent and for at least 30 days after treatment discontinuation, up to 41 months.
Metabolism and nutrition disorders Hyperglycemia	3.2% 1/31 • Adverse events (AEs) will be recorded from the time of consent and for at least 30 days after treatment discontinuation, up to 41 months.
Vascular disorders Hypertension	9.7% 3/31 • Adverse events (AEs) will be recorded from the time of consent and for at least 30 days after treatment discontinuation, up to 41 months.
General disorders Edema	9.7% 3/31 • Adverse events (AEs) will be recorded from the time of consent and for at least 30 days after treatment discontinuation, up to 41 months.
Investigations Weight Gain	6.5% 2/31 • Adverse events (AEs) will be recorded from the time of consent and for at least 30 days after treatment discontinuation, up to 41 months.
Psychiatric disorders Insomnia	3.2% 1/31 • Adverse events (AEs) will be recorded from the time of consent and for at least 30 days after treatment discontinuation, up to 41 months.

Additional Information

Dr. Benjamin Gartrell

Montefiore Medical Center

Phone: 718-405-8404

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place