Keytruda falls hard at gastric cancer hurdle

pharmafile | December 18, 2017 | News story | Research and Development, Sales and Marketing |  MSD, biotech, drugs, keytruda, pharma, pharmaceutical 

There was a time when PD-1/L1 immunotherapy treatments could do no wrong, blasting through indication after indication. However, the limits of the therapies are beginning to be found with a series of surprise failures across a number of indications.

The first major one was Opdivo’s failure as first-line treatment in lung cancer, after this ice-breaker, of sorts, there have been a number of subsequent failures that have called into question how far the treatments can be pushed.

MSD’s Keytruda is the latest treatment to fail, after it was unable to show benefit over standard treatment as second-line for patients with gastric or gastroesophageal junction adenocarcinoma.

The treatment wasn’t just unsuccessful in hitting its endpoint, it was unable to show any real bright spots in the data. Keytruda missed its primary endpoint of improving overall survival in patients whose tumours expressed PD-L1 and was unable to display statistical significance in progression-free survival.

The result brings into question the immunotherapy’s approval as third-line treatment in the same area, though MSD stressed that its indication will remain unchanged.

It’s by no means the only treatment to struggle in the area – only last month, Pfizer and Merck KGaA’s Bavencio also failed to improve overall survival in advanced gastric cancer.

It seems that the stomach cancer indications, though a large population area, may be difficult to adequately treat with the PD-1/L1 treatments. Though, this will not stop MSD continuing with its on-going trials into whether Keytruda can be used as a monotherapy or with chemotherapy as first-line treatment in the same indication.

However, there is no a growing case against approving the immunotherapies in small data sets through the accelerated access pathway. Tecentriq, for example, failed in a Phase 3 study to confirm its use as second-line treatment for bladder cancer – an indication already given provisionally through Phase 2 data.

With more frequent failures to consolidate on smaller data samples, the FDA may react with more caution now on approvals for the treatments. For MSD, the one setback won’t stop its program to test Keytruda in a number of indications – with more than 650 trials currently on-going to broaden its use.

Ben Hargreaves