Can Pfizer and Merck KGaA parlay Bavencio combo data into a kidney cancer win?

Pfizer and Merck's PD-L1 checkpoint inhibitor Bavencio previously won an FDA breakthrough designation for its Inlyta combo in kidney cancer. (Pfizer)

Pfizer and Merck KGaA are one step closer to a brand-new market for their immuno-oncology drug Bavencio. The companies reported winning data in a kidney cancer trial, setting them up for a "breakthrough" FDA approval—and a key expansion for the latecomer PD-L1 drug.

What's more, the potential nod puts Bavencio alongside Pfizer's Inlyta, a follow-up drug to its kidney cancer standard, Sutent. That means a new approval wouldn't just rev up Bavencio sales, but could drive Inlyta forward, too.

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In an interim analysis of the Javelin Renal study, the Bavencio-plus-Inlyta combo bettered Sutent alone at fending off kidney cancer's advance in previously untreated patients. And it wasn't just PD-L1 positive patients who showed a "statistically significant improvement" over Sutent monotherapy, but also patients who didn't test positive PD-L1 expression of 1% or more.

The partners plan to take the data to regulators to support their application for a new approval and are submitting the numbers for presentation at an upcoming medical meeting. The trial will go on to assess whether the combo can help patients live longer.

A new first-line combo approval would obviously be good news for Pfizer and Merck, particularly given Bavencio's fourth-to-market status in the PD-1/L1 market, behind Bristol-Myers Squibb's blockbuster Opdivo, Merck & Co.'s powerhouse Keytruda and Roche's Tecentriq. With Inlyta having flunked a trial aiming for a monotherapy expansion in patients after surgery, the combo approval will be especially important for Pfizer's hopes for both drugs.

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But kidney cancer is heating up, and once again Bavencio is behind. Opdivo and fellow BMS drug Yervoy won a first-line combo approval in April, and Roche’s Tecentriq-plus-Avastin one-two punch put up its second phase 3 win back in February. A Keytruda-Inlyta phase 3 trial is currently ongoing, and Keytruda and Eisai's Lenvima—which Merck & Co. now shares—nabbed a breakthrough designation for first-line kidney cancer, too.