Breast Cancer Coverage from Every Angle

Real-World Data on Palbociclib Plus Endocrine Therapy in Men With Advanced Breast Cancer

By: Melissa E. Fryman, MS
Posted: Tuesday, August 20, 2019

Men with metastatic breast cancer seem to benefit from a combination of the CDK4/6 inhibitor palbociclib and endocrine therapy, according to real-world evidence presented by Kenneth R. Carson, MD, PhD, of Flatiron Health, and colleagues at the 2019 American Society for Clinical Oncology (ASCO) Annual Meeting in Chicago (Abstract 1055). “Given the challenges of conducting randomized clinical trials in men with [metastatic breast cancer], noninterventional, real-world evidence data appear to be useful to delineate the benefit of such therapies in this setting,” the authors concluded.

In this study, pharmacy and medical claims, as well as electronic health record data, from two companies, IQVIA and Flatiron Health, were retrospectively analyzed. The data from IQVIA were used to characterize the duration of treatment for palbociclib combined with endocrine therapy (aromatase inhibitor or fulvestrant); the data from Flatiron Health were used to determine the clinical effect of adding palbociclib to treatment of men with metastatic breast cancer. The IQVIA data were based on 147 patients, and the Flatiron Health data centered on 12 patients, receiving the combination for any line of therapy.

Results from the IQVIA data analysis showed the median duration of therapy was longer for 37 patients who received palbociclib plus endocrine therapy as a first-line regimen, compared with 214 patients who received endocrine therapy alone (8.5 vs. 4.3 months, respectively). Specifically, the median duration of therapy was longer for 26 patients receiving palbociclib plus letrozole, versus 63 patients receiving letrozole alone (9.4 vs. 3.0 months). Results from the Flatiron Health data analysis indicated the maximum response rate for palbociclib plus endocrine therapy to be 33.3% versus 12.5% for the endocrine-alone group.

Disclosure: The study authors’ disclosure information may be found at Many of the authors are employees of Pfizer, the manufacturer of palbociclib.

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