We are glad to announce that the final results for the BioPER trial have been published in the journal Clinical Cancer Research. This study was a research initiative led by Dr. Antonio Llombart-Cussac, Head of the Medical Oncology Service at the Arnau de Vilanova Hospital in Valencia, sponsored by MEDSIR and funded by Pfizer.
BioPER trial is a proof-of-concept study to provide evidence for the role of continued CDK4/6 inhibition in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer progressing from a prior CDK4/6 inhibitor-containing regimen.
The combination of CDK4/6 inhibitors plus endocrine therapy has become the standard of care in front-line therapy for HR+/HER2- advanced breast cancer patients. However, the optimal treatment after progression on a CDK4/6 inhibitor remains unknown in this patient population. Accordingly, new therapeutic strategies are being developed. BioPER trial has been designed to explore the efficacy and safety of continuing palbociclib in combination with a different endocrine therapy agent beyond progression on prior palbociclib-based regimen, and to identify patients who were most likely to benefit from this clinical approach.
BioPER was an international, non-controlled, open-label phase II trial, across 21 study sites in Spain and Italy, that recruited 33 patients with HR+/HER2- advanced breast cancer who had experienced disease progression after having achieved clinical benefit on the immediately prior palbociclib plus endocrine therapy regimen. Clinical benefit rate was 34.4% and 13.0% of tumors showed loss of Rb protein expression, meeting both co-primary endpoints with a tolerable safety profile. A signature that included baseline mediators of therapeutic resistance to CDK4/6 inhibitors and endocrine therapy (low Rb score, high cyclin E1 score, ESR1 mutation) strongly predicted worse outcome, representing a promising biomarker to identify those patients who may not benefit from this therapeutic strategy.
"BioPER is the first prospective published trial to evaluate the antitumor activity, safety, and predictive biomarkers of palbociclib rechallenge in HR+/HER2- advanced breast cancer patients, and its encouraging findings support further investigation in larger randomized controlled trials", Dr. Llombart said.