Merck ($MRK) is confident that its Keytruda (pembrolizumab) will work well in combination with traditional forms of chemotherapy. Up next are next-gen combos with new efforts such as cancer vaccines and IDO inhibitors. Its optimism is running high as it comes off a highly coveted first monotherapy, first-line FDA approval for the drug to treat non-small cell lung cancer (NSCLC).
The pharma is leaving no stone unturned in its Keytruda combo efforts; it has more than 200 ongoing combination studies in more than 30 different tumor types. The PD-1 inhibitor is in more than 30 registration studies in 22 different malignancies with in excess of 360 clinical studies in total as a monotherapy and combo.
“There is reason to believe that combinations of traditional chemotherapeutic agents, perhaps acting through an immune activation mechanism, will work in concert with Keytruda to provide superior responses in advanced lung cancer patients in the future,” said Merck Research Labs EVP and Merck President Dr. Roger Perlmutter on an Oct. 25 earnings call about recent Phase II data. “Additional confirmatory studies, including our KEYNOTE-189 and KEYNOTE-407 studies, are already underway.”
The FDA approved Keytruda on Oct. 24 to treat first-line, metastatic NSCLC in patients with high PD-L1 expression or 50% or more and no EGFR or ALK genomic tumor aberrations. It also expanded second-line use to metastatic NSCLC whose tumors express PD-L1 at 1% with disease progression on or after platinum-containing chemotherapy.
Keytruda only has about a 10% market share in second-line NSCLC in the U.S. But it expects its market share to expand as PD-L1 testing is rapidly becoming standard and with the first-line approval. The drug had $356 million in sales during the third quarter, an increase of 124% over the same quarter a year earlier.
The majority of Keytruda’s market share comes in patients who are expressing PD-L1 at 50% or greater. And testing to find those patients is becoming the standard of care.
“Approximately 60% of U.S. physicians are testing for PD-L1. … So right now if you look at physicians across the U.S. that treat lung cancer, we believe about 60% of them test at least sometimes test for PD-L1. We also believe that about 40% of non-small cell lung cancer new patients are being tested for PD-L1,” said Merck EVP and President of Global Human Health Adam Schechter.
Merck made a point to highlight a couple of novel immunotherapies, particularly Amgen’s ($AMGN) T-Vec cancer vaccine and Incyte’s ($INCY) IDO inhibitor.
“With immune active agents like T-Vec, there's impressive evidence of activity. There's evidence of activity with other immunologic agents, but there's also as we've talked about very impressive combination activity with chemotherapy,” noted Perlmutter.
As for Incyte, its IDO1 inhibitor is in a Phase III advanced or metastatic melanoma trial in combination with Keytruda with data anticipated in 2018. Merck expects to announce a decision around the middle of next year as to whether to test this combo in a Phase III lung cancer study.