Rigel Pharmaceuticals Finalizes Licensing Deal for Breast Cancer Drug

The agreement, which became effective June 11, 2026, required Rigel to issue an upfront payment of $70 million, to be split equally between Arvinas and Pfizer. By securing these rights, Rigel adds a targeted therapy for adult patients with estrogen receptor-positive, HER2-negative, and ESR1-mutated metastatic breast cancer to its portfolio.

VEPPANU is indicated specifically for patients who have seen their disease progress after at least one line of endocrine therapy. As the company prepares for the August rollout, it has issued clinical warnings regarding the drug’s potential side effects, which include QTc interval prolongation and embryo-fetal toxicity. Rigel’s management notes that while the drug offers a new option for patients, the commercial success of the product depends on physician adoption and market acceptance, alongside the firm’s ability to manage the transition of development and manufacturing responsibilities from its partners.