Two separate FDA-approved companion diagnostic tests are now required to determine PD-L1 levels in tumor tissue for those who are cisplatin-ineligible.
Pembrolizumab is now indicated for the treatment of patients who are not eligible for cisplatin-containing chemotherapy and whose tumors have a Combined Positive Score (CPS) for PD-L1 expression of greater than or equal to 10, or in patients who are not eligible for any platinum-containing chemotherapy regardless of PD-L1 status. The FDA approved the Dako PD-L1 IHC 22C3 PharmDx Assay for determining PD-L1 expression, through staining in tumor and immune cells, before prescribing pembrolizumab.
Atezolizumab is now indicated for the treatment of patients who are not eligible for cisplatin-containing chemotherapy, and whose tumors show PD-L1 expression through stained tumor-infiltrating immune cells covering greater than or equal to 5% of the tumor area, or patients who are not eligible for any platinum-containing therapy regardless of level of tumor PD-L1 expression. The FDA approved the Ventana PD-L1 (SP142) Assay as a companion diagnostic test to determine PD L1 expression in immune cells before prescribing atezolizumab.
PI is updated for both drugs to require use of an FDA-approved test for selection of patients being treated in the first-line setting who are cisplatin-ineligible, but second-line indications in urothelial carcinoma for both drugs remain unchanged, according to an FDA.