In PD-1 rivalry, Merck's Keytruda catches up with Opdivo in rare lung cancer type

Merck & Co. refuses to give Bristol Myers Squibb the comfort of an immunotherapy monopoly in a rare type of lung cancer.

Merck’s Keytruda, used in combination with chemotherapy, significantly improved survival of patients with unresectable malignant pleural mesothelioma in a phase 2/3 trial, the company said Friday.

Malignant mesothelioma is a cancer that starts in the lining tissue of certain internal organs. Pleural mesothelioma develops in the lungs and accounts for about 75% of all cancerous mesothelioma cases, which numbered more than 30,000 worldwide in 2020, according to Merck.

Merck said it’ll discuss the data with regulatory authorities. The New Jersey pharma isn’t the sponsor of the cooperative group-led trial but supplied Keytruda and offered support.

If approved, Keytruda will be able to challenge BMS' combination of Opdivo and Yervoy in this indication. The BMS PD-1/CTLA-4 combo became the first immunotherapy treatment for previously untreated unresectable malignant pleural mesothelioma thanks to an FDA approval in October 2020.

BMS' chemo-free regimen cut the risk of death by 26% over platinum-based chemo at an interim analysis of the phase 3 CheckMate-743 trial. Patients on the pure immunotherapy arm lived a median 18.1 months, versus 14.1 months in the control group.

As for Keytruda, investigators launched the Keynote-483 study in this setting around the same time BMS kicked off its Opdivo-Yervoy trial in late 2016, according to Now, the Keytruda-chemo cocktail showed a statistically significant and clinically meaningful improvement in overall survival at the final analysis, Merck said.

Merck plans to share full details from the trial at an upcoming medical meeting.

Keytruda’s combination with platinum-based chemo has already become a standard of care in front-line metastatic non-small cell lung cancer (NSCLC). For its part, BMS won FDA approvals in 2020 for Opdivo and Yervoy as first-line treatment for PD-L1-positive NSCLC and for a Opdivo-Yervoy-chemo regimen regardless of PD-L1 status.

Opdivo is currently no match to Keytruda in terms of popularity. In 2022, Keytruda sales jumped 22% year over year to $20.9 billion. Opdivo sales climbed 10% during the same period, reaching $8.25 billion.

In NSCLC, the two companies—and other PD-1/L1 players—are moving their offerings to early-stage disease for use around surgery.