Results from a Phase 2 study evaluating pembrolizumab in combination with eribulin for hormone receptor-positive, HER2-negative (HR+/HER2-) metastatic breast cancer were posted on ClinicalTrials.gov on 2025-02-19. The trial reported a median progression-free survival (PFS) of 6.03 months for the combination therapy.
Background
The study focused on female patients diagnosed with hormone receptor-positive/HER2-negative metastatic breast cancer (MBC). Participants in this trial had previously received at least one, but not more than two, prior chemotherapeutic regimens for locally recurrent and/or metastatic disease. Prior therapy was required to include an anthracycline and a taxane, and prior anti-hormonal therapy was mandatory.
Trial design
This multicenter, open-label, Phase 2 clinical trial (NCT03222856) was designed to assess the efficacy and safety of pembrolizumab in combination with eribulin. The study was completed with an enrollment of 44 participants. The primary condition investigated was Breast Cancer, specifically HR+/HER2- metastatic breast cancer in a previously treated population.
Key results
The trial reported several key efficacy and safety measurements for the pembrolizumab + eribulin combination:
- The clinical benefit rate (CBR) was observed in 25 Participants.
- For subjects with programmed death ligand-1 (PD-L1) positive tumors, the CBR was observed in 9 Participants.
- The median progression-free survival (PFS) was 6.03 months (95% Confidence Interval).
- The median PFS in subjects with PD-L1 positive tumors was 5.27 months (95% Confidence Interval).
- The median overall survival (OS) was 14.23 months (95% Confidence Interval).
- The mean OS in subjects with PD-L1 positive tumors was 13.6 months (95% Confidence Interval).
- The overall response rate (ORR) based on RECIST v1.1 was observed in 18 Participants.
- The ORR in participants with PD-L1 positive tumors based on RECIST v1.1 was observed in 8 Participants.
- The median duration of response (DoR) was 6.23 months (95% Confidence Interval).
- The median DoR in subjects with PD-L1 positive tumors was 5.23 months (95% Confidence Interval).
- Regarding safety and tolerability, the number of adverse events (AEs) per CTCAE grade was reported as 424 and 192.
What this means
The results from this Phase 2 study provide insights into the activity of pembrolizumab plus eribulin in heavily pre-treated HR+/HER2- metastatic breast cancer. The reported median PFS of 6.03 months and median OS of 14.23 months suggest potential clinical benefit in this challenging patient population. The data also offers specific outcomes for PD-L1 positive subgroups, which may help guide future research and patient selection strategies.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03222856, titled "Ph II Study of Pembrolizumab & Eribulin in Patients With HR+/HER2- MBC Previously Treated With Anthracyclines & Taxanes," were posted on 2025-02-19 on clinicaltrials.gov.