Merck has paused new enrolment in two studies assessing its immunotherapy Keytruda treatment in combination with other therapies in multiple myeloma to address safety concerns.

An external Data Monitoring Committee has recommended the move in order to allow for additional information to be collected to “better understand more reports of death” in the Keytruda (pembrolizumab) groups.

The Phase III KEYNOTE-183 trial is comparing Celgene’s Imnovid (pomalidomide) and low-dose dexamethasone with Keytruda to Imnovid and low-dose dexamethasone alone in patients with refractory or relapsed and refractory multiple myeloma who have undergone at least two lines of prior treatment.

KEYNOTE-185 is a Phase III study comparing Celgene’s Revlimid (lenalidomide) and low-dose dexamethasone with Keytruda to lenalidomide and low-dose dexamethasone alone in patients with newly diagnosed and treatment-naïve multiple myeloma who are ineligible for autologous stem cell transplant (Auto-SCT).

Keytruda was first approved in the US in 2014 for the treatment of advanced or unresectable melanoma. The PD-1 inhibitor has also been approved across a number of other indications, across lung cancer, head and neck cancer, classical Hodgkin Lymphoma, urothelial carcinoma and Microsatellite Instability-High (MSI-H) cancer.