Examining Persistence for Ibrance (palbociclib) for FDA Approved indication and dosing through a retrospective analysis

Abstract

Specific Aims: To determine whether receiving all medication therapy from a single pharmacy positively impacts medication adherence and lengthens duration of therapy in patients who are taking palbociclib for the treatment of HR+, HER2- metastatic breast cancer. Methods: In a retrospective cohort study, we analyzed 347 patients concurrently taking palbociclib and letrozole or fulvestrant. Patients with HR+, HER2- metastatic breast cancer currently on combination therapy of palbociclib and letrozole or fulvestrant filling at Avella Specialty Pharmacy between March 2016 to December 2017. Patients were divided into two groups characterized by those that filled both agents at Avella Specialty Pharmacy and those that only filled palbociclib at Avella and the other agent at a retail pharmacy. We compared the mean length of therapy, the PDC mean, and payor type between both patient groups. Primary outcome was the Proportion of Days Covered (PDC). Secondary outcomes included days on therapy and payor type. Main Results: Data analysis was conducted among the 347 patients (mean age = 69.37; SD = 11.40). Comparison of PDC mean resulted in no significant difference (SPP mean = 94.5%, SD = 0.11; Non-SPP mean = 95.06%, SD = 0.09; t-test p-value = 0.82/Mann-Whitney U test p-value = 0.76). Days on therapy presented no significant difference (SPP mean = 177.81, SD = 136.95; Non-SPP mean = 173.09, SD 157.69; t-test p-value= 0.83/Mann-Whitney U test p-value: 0.07). Comparison of payor type between patient groups had no significant difference (p-value = 0.13). Conclusions: Adherence and length of therapy for patients filling both agents at Avella were similar to those filling the second agent at an alternative retail pharmacy.