Age does not affect palbociclib dose reduction, discontinuation in breast cancer patients

The age of patients with advanced breast cancer appears to have no influence on the rate of palbociclib dose reductions or discontinuations secondary to neutropaenia, a study has shown.

“Older (≥60 years) patients were more likely to start palbociclib at lower doses which may impact neutropaenia and non-neutropaenic intolerance,” the investigators said.

This single-centre, retrospective chart review sought to examine the association of age (<60 vs ≥60 years) with palbociclib dose reductions or discontinuations secondary to neutropaenia. The investigators included hormone receptor-positive, human epidermal growth factor receptor-2 negative advanced breast cancer patients (aged ≥18 years) treated with palbociclib between April 2015 and May 2020.

Patients aged <60 years at treatment initiation were included in the younger cohort, while those aged ≥60 years were categorized as the older cohort.

A total of 107 patients were included. Younger patients were less likely to initiate palbociclib at a dose of <125 mg than older ones (0 percent vs 11.9 percent; p=0.02).

No between-group differences were seen in palbociclib dose reductions or treatment discontinuations secondary to neutropaenia (35.4 percent vs 42.4 percent; p=0.55).

There were also no differences observed in the total number of palbociclib dose reductions (none: 54.2 percent vs 49.1 percent; one: 33.3 percent vs 42.4 percent; two: 12.5 percent vs 8.5 percent; p=0.61) and the final dose (125 mg: 54.2 percent vs 40.7 percent; 100 mg: 29.2 percent vs 27.1 percent; 75 mg: 16.7 percent vs 32.2 percent; p=0.17) between younger and older patients.

“Palbociclib is a small-molecule cyclin-dependent kinase 4/6 inhibitor used to treat hormone receptor-positive, human epidermal growth factor receptor-2 negative advanced breast cancer,” the investigators said.