The CDK4-6 inhibitor palbociclib, combined with hormonal therapy is a new standard of treatment for HR+ Metastatic Breast Cancer. Before the European Medicines Agency approval, a Temporary Authorization for Use (TAU) has been set up in France restricted to patients pretreated with everolimus. We present the efficacy data of this combination in this population.
Between November 2015 and November 2016, all the patients treated with palbociclib + fulvestrant according to the TAU in our institution were prospectively included. Datas from their medical records and adverse events (AE) were collected.
60 patients received at least one dose of palbociclib in combination with fulvestrant with a median age of 61 years. 50 patients (83.3%) had visceral metastasis and 10 (16.7%) had bone only disease. Patients had received an average of 5.3 lines of treatment before palbociclib initiation, including hormonal therapy (mean = 3.0) and chemotherapy (mean = 2.3). Of note, 28 patients (46.7%) had received fulvestrant previously and all had been pretreated with everolimus. With a median follow-up of 8.1 months, median progression free survival (PFS) was 6.1 months (95% CI, 4.2 to 7.4) and median overall survival was not reached. PFS was the same according to the presence of visceral metastasis or no (HR 1.46 (95% CI, 0.57 to 3.74), p = 0.42). Interestingly, patients treated previously with fulvestrant and subsequently re-challenged with fulvestrant and palbociclib had a PFS of 6.4 months, which was similar to patients who didn’t receive fulvestrant previously (HR = 1.00 (95% CI 0.55 to 1.83), p = 1.00). The most common AE were neutropenia (n = 53), thrombocytopenia (n = 25) and anemia (n = 20). At the time of this analysis (April 2017), 36 patients received a further line of treatment after progression.
In this heavily pretreated population, the association of fulvestrant plus palbociclib provides an interesting median PFS of 6.1 months. Patients previously treated with fulvestrant seem to derive the same magnitude of benefit compared to fulvestrant naive patients.
Clinical trial identification
Legal entity responsible for the study
Institut de Cancérologie de l'Ouest
All authors have declared no conflicts of interest.