Palbociklib

Additional information

Palbociclib is an oral, cyclin-dependent kinase inhibitor that prevents the deactivation of the retinoblastoma susceptibility gene protein, thereby interfering with tumor cell progression [1]. It is used in postmenopausal women with a HR-positive, HER2-negative metastatic breast cancer [1-2].

Pharmacokinetics and dosing

The producer reports that sex did not affect exposure of palbociclib (50 men, 133 women) and no dose adjustment based on sex is thus recommended [2].

Effects

No studies with a clinically relevant sex analysis regarding effect of palbociclib have been found

Adverse effects

Neutropenia is a dose limiting adverse effect of palbociclib [3]. In a pooled analysis of three studies (50 men, 135 women) the baseline absolute neutrophile count was 34% higher in men [4].

Reproductive health issues

Palbociklib should be avoided during pregnancy. Human data is lacking but animal data suggest a teratogenic risk. Therefore, both women and men using palbociclib should us effective contraception [1,2]. Regarding teratogenic aspects, please consult Janusmed Drugs and Birth Defects (in Swedish, Janusmed fosterpåverkan).