- Pfizer and Merck KGaA discontinued another late-stage ovarian cancer study testing Bavencio, their PD-L1 antibody, after previous data failed to show sufficient benefit, the companies said Tuesday.
- Executives said the decision was based on multiple factors, including efficacy results in frontline ovarian cancer as well as the recent regulatory approval of a PARP inhibitor in the frontline maintenance setting. The decision was not due to safety reasons, the companies stated.
- The discontinuation marks Bavencio's third consecutive unsuccessful trial in ovarian cancer. Two other studies read out in late 2018, with both lacking compelling efficacy.
Pfizer and German Merck started this Phase 3 study, called JAVELIN Ovarian PARP 100, last July. A lot has changed since then, leading to its cancellation less than a year in. The study was originally expected to run until 2026.
Last November, the partnering pharmas said the late-stage JAVELIN Ovarian 200 trial failed to meet its primary endpoints of overall or progression-free survival in ovarian cancer. The following month, Merck and Pfizer ended another study, JAVELIN Ovarian 100, early after disclosing interim data.
To make matters more difficult for the big pharmas, AstraZeneca and Merck & Co. gained a U.S. regulatory OK for their PARP inhibitor, Lynparza (olaparib), as a frontline maintenance therapy last December. That first-line approval, for BRCA-mutated advanced ovarian cancer, was the first of its kind for a PARP inhibitor.
Those events have shifted the therapeutic context for JAVELIN Ovarian PARP 100, which tested three treatment paths, including two that incorporated Pfizer's PARP inhibitor, Talzenna (talazoparib).
The first arm was a combination of Bavencio (avelumab) and chemotherapy followed by maintenance treatment of Bavencio and Talzenna. The second arm tested Avastin (bevacizumab) and chemotherapy, followed by Avastin for maintenance. The third arm used only chemotherapy and then Talzenna for maintenance.
A Pfizer spokesperson told BioPharma Dive the study has enrolled about 60 patients so far and no formal analyses have been performed for the trial.
In addition to its recent spate of setbacks as an ovarian cancer treatment, Bavencio has also fallen short in previous studies in gastric cancer and non-small cell lung cancer. The Food and Drug Administration gave Bavencio accelerated approvals in Merkel cell carcinoma and urothelial carcinoma in 2017.
In the broader space of immuno-oncology, Pfizer and German Merck's PD-L1 candidate has lagged behind the industry leaders, which have steadily won more approvals over time.
And among PD-1 inhibitors, Merck & Co.'s Keytruda (pembrolizumab) and Bristol-Myers Squibb's Opdivo (nivolumab) have strongly outpaced the field, both with the scope of their approved indications and their subsequent sales.