Trial results for tarlatamab in participants with neuroendocrine prostate cancer were posted on ClinicalTrials.gov on 2025-09-12. The Phase 1 study (NCT04702737) reported an Objective Response Rate (ORR) of 12.0% and a Disease Control Rate (DCR) of 36.0% in the dose expansion cohort.
Background
The study investigated tarlatamab in participants diagnosed with neuroendocrine prostate cancer.
Trial design
The Phase 1 study (NCT04702737), titled 'A Study of AMG 757 in Participants With Neuroendocrine Prostate Cancer,' was completed with an enrollment of 41 participants. The trial evaluated tarlatamab in individuals with neuroendocrine prostate cancer. The study's primary objective was to assess the safety and tolerability of tarlatamab and to determine the maximum tolerated dose (MTD) or recommended Phase 2 dose (RP2D).
Key results
The trial results from the tarlatamab dose expansion cohort provided insights into safety, tolerability, and preliminary efficacy.
Regarding safety and tolerability:
- 40 participants experienced one or more treatment-emergent adverse events (TEAEs).
- 40 participants experienced one or more treatment-related adverse events (TRAEs).
- 1 participant experienced dose-limiting toxicities (DLTs).
Key efficacy outcomes included:
- The Objective Response Rate (ORR) was 12.0% (95% Confidence Interval).
- The Disease Control Rate (DCR) was 36.0% (95% Confidence Interval).
- Median Radiographic Progression-free Survival (PFS) was 2.1 months (95% Confidence Interval).
- Median Overall Survival (OS) was 7.9 months (95% Confidence Interval).
- Duration of Response (DOR) was reported as NA months (95% Confidence Interval).
Pharmacokinetic (PK) measurements for tarlatamab included:
- Maximum Serum Concentration (Cmax) geometric mean was 31.1 μg/mL (Geometric Coefficient of Variation: 26) and 31.7 μg/mL (Geometric Coefficient of Variation: 19).
- Concentration at the End of a Dosing Interval (Ctrough) geometric mean was 5.36 μg/mL (Geometric Coefficient of Variation: 36).
- Area Under the Concentration-time Curve Over the Dosing Interval From Time 0 to 336 Hours (AUC336) geometric mean was 4010 hr*μg/mL (Geometric Coefficient of Variation: 28).
What this means
The results from this Phase 1 study of tarlatamab in neuroendocrine prostate cancer indicate that while adverse events were common, dose-limiting toxicities were infrequent. The observed Objective Response Rate of 12.0% and Disease Control Rate of 36.0% suggest preliminary anti-tumor activity in this patient population. These initial findings support further investigation into tarlatamab as a potential treatment option for neuroendocrine prostate cancer, particularly concerning its safety profile and early efficacy signals.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04702737, titled 'A Study of AMG 757 in Participants With Neuroendocrine Prostate Cancer,' were posted on 2025-09-12 on clinicaltrials.gov.