Observational real world data with palbociclib associated to hormone therapy for advanced breast carcinoma.

Objective: Cyclin-dependent kinase 4/6 inhibitors have a synergistic effect  in combination with endocrine therapy. This combination is used as first and  subsequent-line treatment for advanced luminal breast carcinoma because it  increases progression-free survival. We analysed clinical course and toxicity  in patients treated with palbociclib in our hospital and determined potential  associations between these variables and clinicopathological variables.

Method: Observational retrospective study including patients with advanced  or metastatic breast cancer treated with palbociclib plus endocrine therapy at  the Hospital Universitario de Cabueñes between 2017 and 2020. We  analysed clinicopathological variables, toxicity, and survival. Results: In total, 72 women and 1 man (median age: 63 years) received palbociclib plus an  aromatase inhibitor or fulvestrant. When used as firstline treatment,  progression-free survival was 22 months, and as second and subsequent-line treatment, progression-free survival was 13 months. Adverse effects (mainly haematological) were experienced by nearly all any patient, although delays  and dose adjustments were common (61.7% and 42.7%, respectively).  Performance status alone had a significant impact on progression-free  survival (22 months in patients with ECOG 0 vs 12 months in patients with  ECOG ≥ 1; P = 0.021).

Conclusions: Disease stage, age, and performance status do not limit the  use of treatment with palbociclib, nor its combination with aromatase inhibitors or fulvestrant for first or subsequent-line treatment.  Toxicity is easily managed. Real-world results are equivalent to those  published to date.