EU regulators have approved Pfizer’s PARP inhibitor Talzenna to treat patients with BRCA-mutated breast cancer, opening up another front in a rivalry with AstraZeneca’s Lynparza.
The EMA has cleared the drug as a single-agent therapy for inherited (germline) BRCA-positive, HER2-negative locally advanced or metastatic breast cancer, a few months after the FDA backed the same indication in the US.
Talzenna (talazoparib) has a long way to go to catch AZ and Merck & Co’s Lynparza (olaparib), which is heading for blockbuster sales this year after posting first-quarter sales of $237m in breast as well as ovarian cancer.
Meanwhile, Pfizer’s drug will also have to compete with two other PARP inhibitors from Tesaro and Clovis Oncology, which are already approved for ovarian cancer and in late-stage testing for the breast cancer indication.
The approval of Talzenna was based on data from the EMBRACA phase 3 study, which showed impressive activity with a 46% reduction in the risk of disease progression and a more-than-doubled overall response rate (ORR) compared to chemotherapy, at 63% versus 27%.
Lynparza also showed good efficacy in breast cancer and may have an edge over Talzenna in that it has a slightly better side-effect profile – Pfizer’s drug is unique among PARP inhibitors in that it has been linked to hair loss.
Pfizer is trying to carve out a niche in other cancers for its PARP inhibitor, including prostate cancer, whilst advancing in oncology on a broad front with a clutch of new drugs that open up the opportunity for combination therapies
Talzenna is one of four new targeted therapies it is hoping will drive growth in cancer, along with Xalkori follow-up Lorbrena (lorlatinib) in second-line ALK-positive NSCLC, SMO inhibitor Daurismo (glasdegib) for acute myeloid leukaemia, and Vizimpro (dacomitinib) for locally advanced or metastatic EGFR-positive non-small cell lung cancer (NSCLC).
The latest approval is another pillar in its bid to rebuild its oncology franchise that has been hit hard by competition to Xalkori (crizotinib) for ALK-positive NSCLC from Roche’s Alecensa (alectinib), Novartis’ Zykadia (ceritinib), and Takeda’s Alunbrig (brigatinib).
Talzenna was acquired by Pfizer as part of its $14bn takeover of Medivation in 2016, and earlier this month the company made another mid-range acquisition in cancer, agreeing to buy Array BioPharma for $11.4bn and add another two targeted therapies – Braftovi (encorafenib) and Mektovi (binimetinib) for melanoma – to its portfolio.
The Array deal will give Pfizer control of a Talzenna/Mektovi combination in trials for NSCLC and pancreatic cancer, two other cancers which could allow it to sidestep or get ahead of competition in the PARP category.