Palbociclib dose reductions and the effect on clinical outcomes in patients with advanced breast cancer
R.K. Ismail,
J. van Breeschoten,
M.W.J.M. Wouters,
M. van Dartel,
S. van der Flier,
A.K.L. Reyners,
P. de Graeff,
A.M.G. Pasmooij,
A. de Boer,
K.E. Broekman,
D.L. Hilarius
Affiliations
R.K. Ismail
Dutch Institute for Clinical Auditing, Rijnsburgerweg 10, Leiden, 2333AA, the Netherlands; Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, the Netherlands; Corresponding author. Rijnsburgerweg 10, 2333AA Leiden, the Netherlands.
J. van Breeschoten
Dutch Institute for Clinical Auditing, Rijnsburgerweg 10, Leiden, 2333AA, the Netherlands; Department of Medical Oncology, Amsterdam UMC, VU University Medical Center, Cancer Center Amsterdam, De Boelelaan, 1118, Amsterdam, 1081HZ, the Netherlands
M.W.J.M. Wouters
Dutch Institute for Clinical Auditing, Rijnsburgerweg 10, Leiden, 2333AA, the Netherlands; Department of Surgical Oncology, Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066CX, the Netherlands; Department of Biomedical Data Sciences, Leiden University Medical Centre, Albinusdreef 2, Leiden, 2333ZA, the Netherlands
M. van Dartel
Medicines Evaluation Board, Graadt van Roggenweg 500, Utrecht, 3531AH, the Netherlands
S. van der Flier
Coöperatie VGZ U.A, Nieuwe Stationsstraat 12, Arnhem, 6811KS, the Netherlands
A.K.L. Reyners
Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen, 9713 GZ, the Netherlands
P. de Graeff
University of Groningen, University Medical Center Groningen, University Center for Geriatric Medicine, Hanzeplein 1, Groningen, 9700 RB, the Netherlands
A.M.G. Pasmooij
Medicines Evaluation Board, Graadt van Roggenweg 500, Utrecht, 3531AH, the Netherlands
A. de Boer
Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, the Netherlands; Medicines Evaluation Board, Graadt van Roggenweg 500, Utrecht, 3531AH, the Netherlands
K.E. Broekman
Medicines Evaluation Board, Graadt van Roggenweg 500, Utrecht, 3531AH, the Netherlands; Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen, 9713 GZ, the Netherlands
D.L. Hilarius
Department of Pharmacy, Rode Kruis Ziekenhuis, Vondellaan 13, Beverwijk, 1942LE, the Netherlands
Background: This study aimed to provide insights into the real-world use of palbociclib, dose reductions, and drug effectiveness in (older) patients with advanced breast cancer (BC). Patients and methods: Patients with advanced BC treated with palbociclib from 2017 to 2020 were included. The Kaplan-Meier method was used to calculate time to next treatment (TTNT) and overall survival (OS) for patients with or without dose reductions. These clinical outcomes were also compared in subgroup analyses for older patients (≥70 years) and younger patients (<70 years) and for patients discontinuing palbociclib early (<4 administrations). Results: A total of 598 patients with advanced BC were included, with a median age of 64 years. Palbociclib dose reductions occurred in 33% of all patients. Early discontinuation of palbociclib without dose reductions occurred in 23% of the patients. Patients who required a palbociclib dose reduction were older (median age 67 years vs. 63 years). Patients with dose reductions had a significantly higher TTNT of 16.9 vs. 11.4 months (p < 0.001) and median OS of 29.7 vs. 21.9 months (p = 0.003) compared to patients without dose reductions. The TTNT in older patients was significantly longer (16.9 vs. 11.6 months, p = 0.013) than younger patients, but OS was similar (20.7 vs. 26.7 months, p = 0.051). Conclusion: Palbociclib dose reductions occurred in real-world practice similarly to the PALOMA-3 trial. Patients with dose reductions had no poorer outcomes compared to patients not requiring a dose reduction. Older patients treated with palbociclib had more frequent dose reductions, but this did not appear to affect OS.
