Merck/Pfizer’s Bavencio flunks second ovarian cancer trial

Merck KGaA and Pfizer PD-L1 inhibitor Bavencio has missed the mark in its second ovarian cancer trial in a month, this time failing in previously-untreated patients.

Results from a planned interim analysis of the phase III JAVELIN Ovarian 100 trial showed that Bavencio (avelumab) was unable to improve progression-free survival (PFS) compared to control groups when used as a maintenance therapy.

The failure comes just a few weeks after Merck and Pfizer conceded defeat in another phase III trial of Bavencio in ovarian cancer. The JAVELIN Ovarian 200 trial involved patients with platinum-resistant or platinum-refractory ovarian cancer.

The latest study compared initial chemotherapy followed by Bavencio maintenance to chemotherapy plus Bavencio followed by maintenance with the drug, and a control group of chemotherapy followed by observation. All those enrolled had advanced (stage III to IV) ovarian cancer and were being treated for the first time.

The two companies said they are the first to test an immunotherapy in this setting, for which there is a pressing need for new treatments, but sadly found that adding Bavencio to treatment seemed to give no additional benefit.

“Four out of five women with ovarian cancer are diagnosed at advanced stages [and] most women with advanced ovarian cancer ultimately die within five years due to refractory, resistant or recurrent disease,” they said.

They have decided to terminate the trial on the advice of its independent data monitoring committee. It’s another blow to Merck and Pfizer’s ambitions for Bavencio, which has failed to gather much momentum in its approved indications of Merkel cell carcinoma and urothelial carcinoma.

Sales reached just €19 million in the third quarter eclipsed by the $1.9 billion and $1.8 billion respectively for rival checkpoint inhibitors – Merck & Co’s Keytruda (pembrolizumab) and Bristol-Myers Squibb’s Opdivo (nivolumab) – in the same period.

Merck and Pfizer still aren’t giving up hope for Bavencio in ovarian cancer, but the scope of the drug is receding by the month at the moment. They still have one phase III trial on the go, combining Bavencio with Pfizer’s PARP inhibitor Talzenna (talazoparib) which was approved in October for BRCA-mutated, HER2‑negative locally advanced or metastatic breast cancer.

JAVELIN Ovarian PARP 100 is testing Bavencio in combination with chemotherapy followed by maintenance with Bavencio and Talzenna in patients with previously untreated advanced ovarian cancer. However, it isn’t due to report results until 2022, so Merck and Pfizer will need other line extensions if they are to grow Bavencio’s sales quickly.

The two partners recently reported solid results in first-line renal cell carcinoma for Bavencio in combination with Pfizer’s tyrosine kinase inhibitor Inlyta (axitinib), and is due to report first-line data in non-small cell lung cancer (NSCLC) next year.