Can Pfizer's new breast cancer drug Talzenna really make a dent in the PARP field?

The FDA approved Pfizer's PARP inhibitor, Talzenna, to treat breast cancer, but as the fourth-to-market drug in that class, it's facing significant competition from the likes of AstraZeneca and Clovis. Key to its success? Pfizer's efforts to expand Talzenna beyond solo therapy in breast cancer.