Real-world palbociclib dosing patterns and implications for drug costs in the treatment of HR+/HER2- metastatic breast cancer

ABSTRACT

Background: This study described real-world palbociclib dosing patterns and associated impacts on treatment costs for HR+/HER2- metastatic breast cancer (mBC) in the US.

Methods: Postmenopausal women with HR+/HER2- mBC who initiated palbociclib-based therapy (initiation date = index date) between 02/03/2015 (palbociclib approval) and 02/29/2016, and continuous quarterly activity 1 year before and 6 months after the index date, were identified in the Symphony Health Solutions database. Rates of 1) dose reduction (≥25 mg dose decrease/daily), and 2) reduction or interruption (>60 day gap in continuous drug supply) were assessed using Kaplan-Meier analyses. Drug wastage cost was estimated based on overlapping days between two prescription fills: the last original dose fill and the first reduced dose fill.

Results: 1,242 patients initiated palbociclib-based therapy (mean age = 62.7 years, median follow-up = 8.7 months). During the 12-month post-index period, across the first four lines, dose reduction rates were 31.9–33.7% and dose reduction/interruption rates were 63.5–80.9%. A total of 411 (33.1%) patients changed dose, among whom 128 (31.1%) experienced prescription fill overlap (average = 11.1 days). Mean potential drug wastage cost among patients with fill overlap was $5,471.

Conclusions: Most patients receiving palbociclib experienced dose reduction or interruption early in treatment; the associated drug wastage may lead to considerable costs.

KEYWORDS:

• Costs
• dosing patterns
• drug wastage
• HR+/HER2-
• metastatic breast cancer
• palbociclib
• real-world

Declaration of interest

D Tang is an employee of Novartis and owns stock/stock options. EX Du, M Peeples, and J Xie are employees of Analysis Group Inc., which has received consultancy fees from Novartis; N Li and L Chu were employees of Analysis Group, Inc. during the study’s conduct. V Barghout is an employee of VEB HealthCare LLC, which has received consultancy fees from Novartis. Medical writing assistance, provided by Shelley Batts, PhD, an employee of Analysis Group, Inc., was utilized in the production of this manuscript and funded by Novartis. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Additional information

Funding

Funding for this research was provided by Novartis. The study sponsor was involved in all stages of the study research and manuscript preparation.

Notes on contributors

Nanxin Li

Data were collected by Analysis Group and analyzed and interpreted in collaboration with all other authors. Manuscript drafts were prepared by the authors with editorial assistance from a professional medical writer ultimately paid by the sponsor, Novartis. All authors participated in the design of the study, contributed to the manuscript development, and made the decision to submit the manuscript for publication.