The U.S. Food and Drug Administration said the use of Merck & Co. Inc. or Roche Holding AG's cancer treatments may lead to lower survival rate in certain urothelial cancer patients undergoing clinical trials.
Urothelial cancer typically occurs in the urinary system.
According to the FDA, patients receiving Merck's Keytruda or Genentech's Tecentriq as a single therapy had lower survival rates when compared to those receiving chemotherapy, the current standard of care.
The regulator's findings are based on the early reviews of two ongoing clinical trials of the drugs in patients who had not received prior treatment and had low expression of the PD-L1 protein, which plays a major role in suppressing the immune system.
Both companies have stopped enrolling patients whose tumors have low PD-L1 status in the monotherapy arm of the trials — known as Keynote-361 and Imvigor-130, respectively.
Patient enrollment in other arms of the clinical trials remains open.
The FDA also recommended that healthcare professionals offer Keytruda or Tecentriq as a single therapy based only on the criteria on which the drugs were approved.
The medicines are approved for the treatment of urothelial carcinoma patients who are not eligible for chemotherapy, irrespective of their PD-L1 status.
Keytruda and Tecentriq are also approved by the FDA for the treatment of multiple other cancer types.