Palbociclib vs abemaciclib: How to choose the right treatment for breast cancer patients

A study suggests that in choosing CDK4/6 inhibitors (palbociclib and abemaciclib) for patients with hormone receptor-positive, HER2-negative metastatic/recurrent breast cancer, considerations must be made based on the tolerability and manageability of adverse events (AEs).

“Appropriate AE management and maintenance of therapeutic intensity are necessary to achieve therapeutic benefits of CDK4/6 inhibitors in hormone receptor-positive, HER2-negative metastatic/recurrent breast cancer,” the researchers said. 

Sixty patients who received palbociclib and 49 treated with abemaciclib between 1 January 2018 and 30 June 2023 were included in the analysis. The research team compared the rate and reasons for treatment discontinuation, interruption of administration, and changes in dose and dosing schedule, treatment duration, and relative dose intensity (RDI) between the two groups.

More patients treated with abemaciclib discontinued treatment due to AEs, including interstitial lung disease and hepatic and renal events, than those who received palbociclib (12 vs 5 patients; p=0.008).

On the other hand, palbociclib-treated patients had a higher rate of administration interruption (91.9 percent vs 71.4 percent; p=0.004) and dose reduction (67.3 percent vs 47.5 percent; p=0.053) than those who received abemaciclib.

Additionally, the abemaciclib group had a shorter treatment duration than the palbociclib group (median 238 vs 301 days; log-rank test, p=0.581). The median RDI was similar between groups at 59.7 percent for palbociclib and 59.6 percent for abemaciclib (p=0.539).

“Although the AEs of palbociclib and abemaciclib affected the treatment considerably, the treatment duration and RDI were similar,” the researchers said.