Palbociclib or Ribociclib in First-Line Treatment in Patients With Hormone Receptor-Positive/Human Epidermal Receptor 2-Negative Advanced or Metastatic Breast Cancer? A Perspective Based on Pharmacologic Costs

Purpose: To assess the pharmacologic costs of CDK4/6 inhibitors (palbociclib and ribociclib) in hormone receptor-positive (HR+)/human epidermal receptor 2-negative (HER2(-)) advanced or metastatic breast cancer (BC). Pivotal phase 3 randomized controlled trials (RCTs) were considered. Discussion: Two phase 3 RCTs including 1334 patients were considered. European Society for Medical Oncology Magnitude of Clinical Benefit Scale reached grade 3 for the PALOMA-2 and MONALEESA-2 trials. Pharmacologic costs of palbociclib and ribociclib at full dose were similar, at (sic)3864 and (sic)4002 per month of progression-free survival (PFS) gained, respectively. The reduction of dose of ribociclib (36.1% in the pivotal RCT vs. 36.0% of palbociclib in pivotal RCT) resulted in (sic)2718 and (sic)1348 per month of PFS gained at 400 and 200 mg daily, respectively. Conclusion: When pharmacologic costs of drugs are combined with the measure of efficacy represented by PFS, both palbociclib and ribociclib are cost-effective first-line treatments in postmenopausal women with HR+/HER2(-) advanced or metastatic BC, with a lower cost in favor of ribociclib in patients with dose reduction.