Pfizer, Merck KGaA's Bavencio flunks study in hard-to-treat gastric cancer

Immuno-oncology agents have had little luck in stomach cancer and now Pfizer and Merck KGaA's Bavencio can tally up another failure against the tough-to-crack tumor. 

In a test as a maintenance therapy after one round of successful chemo, the anti-PD-L1 drug failed to beat continuing chemo or best supportive care at extending patients’ lives, the companies said Friday.  The study focused on patients with advanced or inoperable tumors.

Even in PD-L1-positive patients, in whom PD-1/L1 inhibitors have historically shown better results, Bavencio didn’t move the needle, the study found.

Advanced gastric cancer is “rarely immunogenic, and to date no immune checkpoint inhibitor has demonstrated superiority to the current standard of care with chemotherapy,” Markus Möhler, the phase 3 Javelin Gastric 100 study’s coordinating investigator, said in a statement. The researchers are now delving deeper into the results for useful information.

This is not the first time Bavencio has disappointed in stomach cancer. The drug in 2017 didn’t outperform chemo at prolonging the lives of patients who'd failed on two prior rounds of treatment.

RELATED: Pfizer, Merck KGaA's Bavencio flops in 'high-risk' stomach cancer trial

Indeed, even the market-leading PD-1 drug, Merck & Co.’s Keytruda, has turned up failures in stomach cancer.

Back in late 2017, Keytruda failed to keep tumors at bay or show a survival benefit in previously treated patients with PD-L1-positive, advanced stomach cancer. That was the Keynote-061 study. Then in April, Merck said the phase 3 Keynote-062 study also failed, as a Keytruda-chemo combo couldn’t outdo chemo alone in previously untreated patients whose tumors express PD-L1.

But Keytruda did show some benefits as a third-line treatment in PD-L1-expressing gastric cancer in the Keynote-059 study, which landed it an accelerated FDA nod in 2017. In that single-arm study—meaning there was no comparator drug—on 259 patients, the Merck drug shrank tumors in about 12% of patients, and those whose tumors expressed PD-L1 were more likely to respond.

RELATED: ASCO: Merck details Keytruda's second stomach cancer slip

Bristol-Myers Squibb’s Opdivo also improved survival against placebo in third-line stomach cancer in Asian patients. In the ONO-4538-12 trial, the drug cut the risk of death by 37%, extending patients’ lives by a median of 5.32 months, versus 4.14 months for placebo.

The latest stomach cancer letdown came after Bavencio, in combination with Pfizer’s Inlyta, won an FDA nod to broaden its reach to first-line kidney cancer. But the drug has to battle Keytruda, which has its own approval in tandem with Inlyta, as well as a combo of Opdivo and Yervoy.

Prior to that, Bavencio had suffered three setbacks in ovarian cancer, the latest one being in a combination with Pfizer’s PARP drug Talzenna in previously untreated patients with Stage III or Stage IV disease.