The European Commission (EC) has approved Pfizer‘s Talzenna (talazoparib) for the treatment of patients with advanced forms of HER2-negative breast cancer with BRCA mutations who have been treated with chemotherapy — before or after surgery, with an anthracycline and/or a taxane — or were not eligible to receive chemotherapy with these agents.

Patients with hormone receptor-positive tumors who have received or were not eligible to be treated with endocrine-based therapy may also be eligible for treatment with Talzenna.

Talzenna is an inhibitor of the poly ADP ribose polymerase (PARP), an enzyme involved in DNA repair and in the control of programmed cell death. By blocking the activity of PARP, Talzenna prevents cancer cells from repairing their DNA, eventually eliminating them.

Last year, the U.S. Food and Drug Administration (FDA) had already approved Talzenna for the treatment of patients with inherited BRCA-mutated, HER2-negative, locally advanced or metastatic breast cancer.

The new approval was largely based on findings from the open-label, randomized EMBRACA Phase 3 trial (NCT01945775), which focused on examining the safety and effectiveness of Talzenna, compared to a chemotherapy agent of choice, in patients with BRCA-mutated, HER2-negative, locally advanced or metastatic breast cancer.

The trial’s findings showed that Talzenna extended the time patients lived without their disease worsening compared to chemotherapy agents (8.6 months versus 5.6 months, respectively), which corresponded to a 46% reduction in the risk of death or disease progression.

Data from the trial also showed that a higher percentage of patients treated with Talzenna achieved a partial or complete response (partial or complete tumor eradication), compared to those treated with chemotherapy (62.6% versus 27.2%, respectively).

With the approval from the EC, Talzenna will now join other PARP inhibitors in the market, including AstraZeneca’s Lynparza (olaparib), which has also been approved for similar indications for the treatment of breast cancer; Clovis Oncology‘s Rubraca (rucaparib), and GlaxoSmithKline‘s Zejula (niraparib). Both Rubraca and Zejula have been approved as maintenance therapies for patients with ovarian cancer and are being tested for the treatment of breast cancer in controlled trials.