FDA Reports Efficacy Issue for Patients Taking Pembrolizumab or Atezolizumab as Monotherapy to Treat Urothelial Cancer with Low Expression of PD-L1

In two ongoing clinical trials (KEYNOTE-361 and IMVIGOR-130), the Data Monitoring Committees’ (DMC) early reviews found patients in the monotherapy arms of both trials with PD-L1 low status had decreased survival compared to patients who received cisplatin- or carboplatin-based chemotherapy. There was no change in the adverse event profile of Pembrolizumab or atezolizumab. Both Merck, manufacturer of Keytruda, and Genentech, manufacturer of Tecentriq, have stopped enrolling patients whose tumors have PD-L1 low status to the pembrolizumab or atezolizumab monotherapy arms per the DMCs’ recommendations.

The clinical trials compare platinum-based chemotherapy combined with pembrolizumab or atezolizumab to platinum-based chemotherapy alone. Both trials enrolled a third arm of monotherapy with pembrolizumab or atezolizumab to compare to platinum-based chemotherapy alone. The monotherapy arms remain open only to patients whose tumors have PD-L1 high status. The combination arms and the chemotherapy arms of both studies also remain open. The FDA is reviewing the findings of the ongoing clinical trials and will communicate new information as necessary.

Both pembrolizumab or atezolizumab are currently approved under accelerated approval for the treatment of locally advanced or metastatic urothelial carcinoma patients who are not eligible for cisplatin-containing chemotherapy, irrespective of PD-L1 status. Patients taking pembrolizumab or atezolizumab for other approved uses should continue to take their medication as directed by their healthcare professional.

Healthcare professionals should be aware that the populations enrolled in the ongoing clinical trials were eligible for platinum-containing chemotherapy, and therefore differ from those enrolled in the trials that led to the accelerated approvals of both pembrolizumab or atezolizumab in the treatment of patients with locally advanced or metastatic urothelial carcinoma who are not eligible for cisplatin-containing chemotherapy. FDA recommends providers select patients for the treatment of locally advanced or metastatic urothelial cancer using the criteria described in Section 14 of each label. These criteria supported the approvals for pembrolizumab or atezolizumab for initial monotherapy in cisplatin-ineligible patients. Pembrolizumab and atezolizumab are also currently approved by the FDA for the treatment of multiple types of other cancers.

Patients should talk to their doctor if they have questions or concerns about either drug. Health care professionals and patients are encouraged to report any adverse events or side effects related to the use of these products and other similar products to FDA’s MedWatch Adverse Event Reporting program (https://www.fda.gov/Safety/MedWatch/ucm2005699.htm).

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