ASCO: Pfizer, Merck KGaA's Bavencio posts win in rare gynecological cancer

Pfizer sign
Pfizer and Merck KGaA won their first FDA approval for Bavencio in 2017. (Tracy Staton)

Pfizer and Merck KGaA’s Bavencio is having itself an ASCO. In addition to putting up game-changing results in bladder cancer, it’s posted a win in a rare, chemo-resistant gynecological cancer, too.

In a small phase 2 study, the checkpoint inhibitor staved off a relapse in 8 of 15 women with gestational trophoblastic tumors that couldn’t be treated with single-agent chemo.

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At 29 months of follow-up, the disease, which develops in the uterus during or after pregnancy, had not returned in those eight patients, according to the results, which debuted ahead of the American Society of Clinical Oncology’s virtual annual meeting.

While the data aren’t practice-changing—doctors will need more evidence before switching up the way they treat the disease, lead author Benoit You, M.D., Ph.D., said—"these are highly promising results,” suggesting Bavencio “could prevent patients with chemo-resistant disease from the severe toxicity of chemotherapy combinations,” he said in a statement.

Bavencio arrived late to the PD-1/PD-L1 party, trailing major players from Merck & Co., Bristol Myers Squibb and Roche. But, while it beat AstraZeneca’s Imfinzi to market, it’s lagged in the sales department thanks to its notable absence on the lung cancer scene and a series of failures in areas including head and neck cancer and stomach cancer.

In the meantime, it’s picked up competition—namely in the form of Merck’s Keytruda, which has stepped on Bavencio's Merkel cell carcinoma turf and taken it on in previously untreated kidney cancer, too.

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But Bavencio may be edging closer to some new niches it can call its own thanks to the gynecological win and a new bladder cancer victory, also unveiled Thursday. In a phase 3 study of patients whose disease hadn’t yet progressed after induction chemo, Bavencio lengthened lives by 7.1 months over best supportive care.