Keytruda makes surprise flop in lung cancer trial

Jan. 8, 2020

It’s been win after win for Keytruda since Merck began testing the immunotherapy on different types of cancer. But this week, the company announced that the monoclonal antibody, which works by blocking the PD-1 pathway where cancer cells can hide from the immune system, failed to significantly extend the life of patients with small cell lung cancer (SCLC).  

Keytruda has already been approved to treat non-small cell lung cancer and is the current leader in that market. But Merck has been in a heated competition to gain market share for SCLC, which accounts for 10-15 percent of all lung cancer cases.

This recent study was a phase 3 trial using Keytruda in combination with chemotherapy. Although it did not extend survival for patients, it did slow the progression of the disease.

One theory as to why Keytruda missed the mark with this particular type of tumor is that it might not be more resistant to PD-1 inhibitors than other similar treatments. Bristol-Myers Squibb’s PD-1 inhibitor, Opdivo, also failed a similar SCLC trial. But two similar types of immunotherapies that instead target the PD-L1 pathway — Roche’s Tecentriq and AstraZeneca’s Imfinzi — have shown more success at treating SCLC.

Tecentriq has already been approved as a first-line treatment against SCLC.

Read the Reuters report.