FDA Suspends Certain Clinical Trials of Merck's Keytruda

The U.S. Food and Drug Administration suspended two clinical trials and a portion of a third testing Merck & Co.'s Keytruda as a treatment for blood cancer, after more patients receiving the drug died than those receiving other treatments, the company said.

Merck said Wednesday the FDA determined the risks of Keytruda, when added to the other drugs the patients in the trial were taking, outweighed any potential benefit for patients with the blood cancer multiple myeloma, based on available data. The other drugs used in the studies are Celgene Corp.'s Pomalyst and Revlimid.

An FDA spokeswoman couldn't immediately be reached to comment.

Merck said all patients in two of the studies and a portion of those in a third study will stop receiving Keytruda. Other studies of Keytruda will continue, including among multiple myeloma patients, Merck said.

Merck is conducting more than 400 clinical trials to test new uses for Keytruda, which is already FDA-approved to treat multiple cancer types including those of the skin and lungs. The drug, introduced in the U.S. in 2014, works by harnessing the body's immune system to attack tumors.

Merck first disclosed the increased patient death rate last month, saying it had paused enrollment for new patients in two of the multiple myeloma studies, based on a recommendation by an external committee monitoring the safety of patients. At that time, Merck said it would allow patients already enrolled in those studies to continue receiving Keytruda.

The third study affected by the FDA suspension tested Keytruda in combination with a variety of older drugs to treat multiple myeloma. A subset of patients receiving Keytruda in combination with Revlimid and another drug, dexamethasone, will discontinue Keytruda treatment, but Keytruda's use among other patients in the study will continue.

A Merck spokeswoman said the company had no further details about the patient deaths in the studies.

Keytruda had sales of $1.4 billion in 2016, which are expected to grow this year as the drug has been approved for additional uses, including to treat any tumor with a certain genetic mutation.

Merck shares fell 1% to $63.50 in after-hours trading after it announced the FDA action. In regular trading, the stock fell 0.17% to $64.16 Wednesday.

Write to Peter Loftus at peter.loftus@wsj.com

(END) Dow Jones Newswires

July 05, 2017 18:40 ET (22:40 GMT)