hydroxychloroquine + palbociclib

Hydroxychloroquine + palbociclib is an investigational combination therapy being studied primarily in hormone receptor-positive, HER2-negative metastatic breast cancer. Hydroxychloroquine is an autophagy inhibitor, while palbociclib is a selective cyclin-dependent kinase 4/6 (CDK4/6) inhibitor. Preclinical and early clinical studies suggest that low-dose continuous administration of palbociclib can activate autophagy as a resistance mechanism; the addition of hydroxychloroquine blocks this process, potentially enhancing antitumor efficacy by promoting senescence and overcoming resistance to CDK4/6 inhibition. This combination has been evaluated in phase I trials with letrozole for safety and preliminary efficacy, showing manageable toxicity and some evidence of clinical benefit[2][3][4][5].

Brand names

Plaquenil (for hydroxychloroquine)Ibrance (for palbociclib)

Other names

HCQ + palbociclib