4CPS-130 Palbociclib combined with hormonal therapy for metastatic breast cancer treatment

BackgroundThe first-in-class oral inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6) palbociclib, combined with hormonal therapy, is a new standard of treatment in the first and second line for hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (mBC).PurposeTo describe the effectiveness and safety of palbociclib combination therapy for mBC in clinical practice.Material and methodsRetrospective and observational study in which the effectiveness and safety of palbociclib was tested by reviewing medical and pharmaceutical records of all patients treated with the drug from December 2015 until April 2018 in a tertiary hospital. Dispensation data was obtained from the Pharmacy Department’s software, Farmatools. Collected data included: age, ECOG performance status, number of cycles received, duration and prior lines of treatment. Effectiveness endpoint was progression-free survival (PFS) according to RECIST version 1.1. Adverse events (AEs) related to treatment with palbociclib and registered in the patient’s medical records were included in the study. Toxicity was evaluated as defined by the NCI-CTCAE, version 4.0.ResultsAbstract 4CPS-130 Table 1 Patients n (%) Female29 (100%) Age (mean)57 (38–71) ECOG 023 (79.3%)14 (13.8%)22 (6.9%) Phenotype Luminal A5 (17.2%)Luminal B24 (82.8%) Menopausic stage Peri5 (17.2%)Post24 (82.8%) Concomitant hormonal therapy Fulvestrant17 (58.6%)Aromatase inhibitor12 (41.4%) Naive Yes6 (20.7%)No23 (79.3%) N of prior lines (mean)1 (0–10) Initial dose 125 mg29 (100%) Dose reductions Yes14 (48.3%)1No5 (51.7%) Suspension/cause Progression9 (31.0%)Toxicity1 (3.5%) N° cycles (mean)9 (1–21) Median treatment duration (95% CI) (months)6.3 (0.1–19.2) Median PFS (95% CI) (months)7.7 (0.1–19.2)Abstract 4CPS-130 Table 2 Adverse events Frequencyn (%) Grade1 2 ≥3 General Asthaenia, fatigue10 (34.5%)4 1 2Headache3 Gastrointestinal Nausea8 (27.6%)4 2Constipation2 Haematological Neutropaenia16 (55.2%)4 12 Skin and mucous membranes Alopecia9 (31.0%)2Mucositis4Dermatitis1 2 Infections Urinary tract infection4 (13.8%)2Tonsillitis1Sepsis1ConclusionA significant difference in PFS was observed compared to published clinical trials PALOMA-2 (PFS 24.8 months) and PALOMA-3 (PFS 11.2 months). Otherwise, palbociclib showed a similar safety profile. However, further studies are required to establish effectiveness in clinical practice as 19/29 patients are still receiving treatment.References and