Pfizer's Next-Generation CDK4 Inhibitor Succeeds in Phase 2
The drug atirmociclib is positioned as a potential successor to the company's blockbuster Ibrance.
Pfizer's next-generation CDK4 inhibitor atirmociclib succeeded in a Phase 2 trial for second-line metastatic breast cancer, according to a news briefing from Endpoints News.
The company is developing atirmociclib as a successor to its breast cancer drug Ibrance, which brought in $1.04 billion in 2025 but faces a patent cliff in 2027,Endpoints reported.
The Phase 2 study met its primary endpoint, though specific efficacy data was not included in the news summary. Atirmociclib is being developed for patients with HR-positive, HER2-negative advanced or metastatic breast cancer who have progressed after prior CDK4/6 inhibitor treatment.
Pfizer has been positioning the drug as a potential first-in-class, next-generation cell cycle inhibitor backbone for this patient population. More details are expected as the data matures.