Dive Brief:

  • An experimental Merck & Co. drug that pairs Keytruda with a new type of immunotherapy did not help people with lung cancer in a Phase 2 clinical trial, the company said Thursday. Merck will continue assessing the drug together with chemotherapy.


  • The drug, dubbed MK-7684A, didn’t significantly delay tumor growth in previously treated patients with non-small cell lung cancer by any more than an older chemotherapy called docetaxel, and “was numerically less effective.” Wall Street analysts said the failure was expected but had higher hopes for the trial arm that tests MK-7684A with docetaxel.


  • The trial is an important test of drugs targeting TIGIT, which like Keytruda try to direct immune cells to kill tumor cells. For Merck, the coformulation of Keytruda with a TIGIT-targeting drug could help protect revenue from its flagship blockbuster, which will have some of its strongest patents expire in 2028.

Dive Insight:

Merck coformulated Keytruda, which earned the company $21 billion in 2022, with a TIGIT-blocking drug called vibostolimab that is being tested on its own in cancers like melanoma.

In the study Merck updated Thursday, the co-formulation was given to non-small cell lung cancer patients who had progressed after treatment with Keytruda or a similar immunotherapy paired with chemotherapy. These patients typically have a poor prognosis and have shown signs of resistance to immunotherapy, making them very challenging to treat, SVB Securities analyst Daina Graybosch wrote in a March 17 note to clients.

In announcing the study missed its goal, Merck said the MK-7684A plus docetaxel arm remains “blinded,” which indicates not enough treated patients have progressed to calculate how well it performed against docetaxel alone. Some Wall Street analysts took this as a sign the chemo combination could eventually delay progression when compared to chemo alone.

The Food and Drug Administration hasn’t approved any TIGIT-blocking drugs and the mechanism has stirred debate among scientists and financial analysts. Another developer, Gilead-partnered Arcus Biosciences, tested a TIGIT therapy in lung cancer with another immunotherapy and, while positive, the results weren’t seen as persuasive.

A Roche TIGIT drug, meanwhile, failed in small cell and non-small cell lung cancer trials, although the Swiss drugmaker continues to test it. Bristol Myers Squibb and GSK also are advancing candidates.

The next big milestone for the approach could come next month, when Merck reveals data from a trial of MK-7684A in melanoma at a cancer research meeting.