Objective
To evaluate progression free survival (PFS) in patients with advanced or metastatic, hormone receptor positive (HR+), HER2-negative (HER2-) breast cancer treated with palbociclib in combination with fulvestrant as second or later lines of treatment. Method: An observational, retrospective study with cohorts in 11 sites in Colombia, extracted from the medical records of women who began treatment between February 2018 and August 2019. Index date was first prescription, and patients were followed until they experienced disease progression, death, treatment discontinuation, were lost to follow-up, or until 12 months of follow-up, whichever occurred first. Kaplan Meier were used to estimate PFS.
Results
Sixty-nine patients who received at least one dose of the drugs were included in the analysis. Median follow-up was 10.81 ± 3.18 months, mean age was 61.2 ± 11.14 years and 96.3% were postmenopausal. At the time of starting treatment, 52 were in stage IV, with 59 with > 2 sites of metastasis. All patients started on palbociclib 125 mg. 23 reported discontinuation, 10 of them permanently but none due to neutropenia. Clinical benefit rate was 69.35%, and median PFS was not achieved at 12 months. One death was reported due to disease progression.
Conclusion
Effectiveness of Palbociclib for patients with HR+/HER2- advanced or metastatic breast cancer treated with palbociclib in combination with fulvestrant as second or later lines of treatment in Colombia is consistent with the efficacy observed in clinical trials while maintaining a good safety profile. Implications for practice: Real-world data from Colombia for the first time indicates the combination of palbociclib + fulvestrant is associated with high levels of effectiveness in women with HR+/HER2- advanced or metastatic breast cancer, even in third or later lines of treatment. Although neutropenia was frequent and, in some cases, clinically significant, no patients required permanent treatment discontinuation due to this event. All of the adverse effects resolved without sequelae, and no deaths due to this cause were seen. This confirms an adequate safety profile for the drug combination.