PF-07104091 + PF-07220060 + letrozole

PF-07104091 + PF-07220060 + letrozole is an investigational oral combination therapy under clinical development for the treatment of hormone receptor-positive, HER2-negative breast cancer and other solid tumors. Both PF-07104091 and PF-07220060 are small molecule inhibitors targeting cyclin-dependent kinases (CDKs), with distinct selectivity profiles: PF-07104091 is a cyclin-dependent kinase 2 (CDK2) inhibitor, while PF-07220060 is a next-generation, potent cyclin-dependent kinase 4 (CDK4)-selective inhibitor that spares CDK6. Letrozole is an established aromatase inhibitor used in endocrine therapy to reduce estrogen production. The combination aims to overcome resistance to prior CDK4/6 inhibitors and endocrine therapies by dual inhibition of cell cycle regulators alongside estrogen suppression. Developed by Pfizer, this regimen is being evaluated in phase I/II clinical trials for safety, tolerability, pharmacokinetics, and preliminary efficacy in patients with advanced or metastatic breast cancer who have progressed on previous treatments[1][4][5][6].

Other names

Atirmociclib + Tegtociclib + letrozole