On a roll, Merck blazes through a new segment of the biomarker trail
Merck has notched an approval for using Keytruda to treat a biomarker-based subset of first-line colorectal cancer patients with unresectable or metastatic tumors, as the pharma giant continues to find new niches for its blockbuster PD-1 star.
The OK is significant in a number of ways. Not only does it build on an accelerated approval for all tumors characterized as microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR); it also marks the first single treatment for colorectal cancer that doesn’t contain chemotherapy.
“Metastatic colorectal cancer is a serious and life-threatening disease with a poor prognosis. Available current therapy with chemotherapy combinations and other biologics are associated with substantial toxicity,” Richard Pazdur, the face of the FDA’s fast-moving oncology unit, said in a statement. “Having a non-chemotherapy option available for selected patients is a noteworthy paradigm shift in treatment.”
Keytruda beat out a number of chemo-based regimens in a head-to-head study read out recently, almost doubling the median progression-free survival. Median PFS in the Keytruda group was 16.5 months while the standard-of-care arm — featuring pairings like mFOLFOX6 plus bevacizumab — lived 8.2 months before passing away or seeing the cancer return.
The KEYNOTE-177 study is still ongoing to measure overall survival.
The FDA granted priority review for the indication just days after Merck touted the topline win in early April. It also ushered the company down the real-time oncology review (RTOR) pilot program, coming up with a thumbs up less than a month after the official sBLA submission.
Around 5% of all metastatic colorectal cancer have MSI-H or dMMR tumors, which contain abnormalities that affect the proper repair of DNA inside the cell. In 2017 Merck made its first foray into the field with an accelerated OK for all cancers bearing this feature regardless of where they originate in the body.
More recently Merck moved into the more well-known space of tumor mutational burden, notching an accelerated approval for unresectable or metastatic TMB-high solid tumors.
The research team is committed to unearth yet more ways to identify patients most likely to benefit from their checkpoint inhibitor, “particularly for those who have few available options,” said CMO Roy Baynes.