The US Food and Drug Administration (FDA) on Thursday released an alert and summary of findings from two halted Merck clinical trials evaluating the use of Keytruda (pembrolizumab) combined with other treatments in patients with multiple myeloma.

The immunotherapy Keytruda is approved by FDA for the treatment of melanoma, lung cancer and other cancers but it is not approved to treat multiple myeloma.

On 3 July, FDA required that all patients in these two trials be discontinued from further investigation because interim results demonstrated an increased risk of death for patients receiving Keytruda in combination with dexamethasone and an immunomodulatory agent (lenalidomide or pomalidomide).

FDA says that Merck was made aware of the issue through an external data monitoring committee recommendation and suspended enrollment in the trials on 12 June.  

Center for Drug Evaluation and Research Director Janet Woodcock said in a statement: "After receiving more information provided by Merck, the FDA acted swiftly in placing a full clinical hold on these trials last month. Patients are no longer receiving treatment with Keytruda in these two trials, which were studying Keytruda for a use that has not been evaluated or approved by the agency."

FDA added: "Other multiple myeloma clinical trials of Keytruda (pembrolizumab), other PD-1/PD-L1 cancer drugs and other combinations are currently undergoing clinical evaluation. The FDA will be working directly with sponsors of Keytruda and other PD-1/PD-L1 cancer drugs, as well as clinical investigators conducting clinical trials in patients with multiple myeloma, to determine the extent of the safety issue. The agency will communicate any new information to the public as soon as it is able."

Also in July, FDA announced it is considering labeling changes to include additional ocular inflammatory conditions for three immune checkpoint inhibitors, including Keytruda.

FDA Alerts Healthcare Professionals and Oncology Clinical Investigators about Two Clinical Trials on Hold Evaluating KEYTRUDA® (pembrolizumab) in Patients with Multiple Myeloma