Merck's Keytruda gives BMS' Opdivo some company with small cell lung cancer nod

Bristol-Myers Squibb's FDA approval for Opdivo in patients with previously treated small cell lung cancer (SCLC) already has looked shaky since the drug failed to extend patients' lives in a phase 3 trial. Now, Opdivo will have to make some room for its archrival, Merck & Co.’s Keytruda, in the same indication.  

The FDA has approved Keytruda as a monotherapy for SCLC patients who have failed platinum-based chemo and at least one other line of therapy, Merck said Tuesday.

Same as Opdivo’s third-line nod doled out last August, the new Keytruda go-ahead was granted under the accelerated approval program based on tumor response rate and duration of response data.

In pooled data from the Keynote-158 and Keynote-028 non-randomized trials, which enlisted 83 metastatic SCLC patients who had failed two or more lines of treatment, Keytruda provoked a response in 19% of participants. Among the 16 who responded, 63% of their tumors continued to respond to Keytruda for a year or longer, according to Merck.

“Small cell lung cancer, which accounts for 10% to 15% of all lung cancers, is often diagnosed at an advanced stage where the prognosis is very poor and there have historically been limited treatment options,” Patrick Ott of the Dana-Farber Cancer Institute said in a statement.

It’s also worth noting that, at least in the Keynote-158 study, the response Keytruda elicited only came from patients whose tumors expressed PD-L1. That kind of skewed efficacy is consistent with Keytruda’s past performance as a solo drug in non-small cell lung cancer.

RELATED: BMS' second small-cell trial flop endangers Opdivo lung cancer approval: analyst

Not meant for direct comparison with Keytruda, in Opdivo’s CheckMate-032 trial, 13 of 109 (12%) of SCLC patients who had received at least two prior lines of therapy responded to treatment, while the benefit lasted a median 17.9 months.

But Opdivo’s potential in SCLC has come under question lately. Setbacks in the CheckMate-331 study in second-line SCLC and in a study testing the Opdivo-Yervoy combo in the maintenance setting following first-line chemo have shaken the BMS drug’s case.

Meanwhile, Roche’s anti-PD-L1 Tecentriq recently became the first immuno-oncology agent to land an FDA green light in newly diagnosed SCLC patients. Baader Helvea analysts previously predicted that the indication could add $1.5 billion to Tecentriq’s sales.

RELATED: In another I-O first for Roche, Tecentriq nabs blockbuster small cell lung cancer nod

Keytruda is also being tested in the first-line setting  in tandem with standard chemo combo carboplatin and etoposide. That phase 3 study currently bears a primary completion date in December, according to

The Merck PD-1 drug has continuously jostled its BMS rival in different tumor types. Just a week ago, Keytruda leapt ahead of Opdivo and nabbed two FDA approvals in previously untreated head and neck cancer, while Opdivo is cleared only for those who have failed on chemo.