top of page


Safety Analysis of PARSIFAL Trial Published in The Oncologist Journal

Updated: Dec 7, 2022

It is critical to gain familiarity with the adverse events of antitumoral drugs since the ability to diagnose and manage these toxicities will allow patient population to effectively continue treat­ment without any significant detrimental outcomes. In this context, we are happy to share that a comprehensive report on the safety profile of patients included in the PARSIFAL study has been published in The Oncologist Journal, paying special attention to rare but serious toxicities associated to the treatment with CDK4/6 inhibitors such as thromboembolic events and interstitial lung disease/pneumonitis.

The PARSIFAL trial 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.

The optimal management of advanced breast cancer has changed dramatically with the introduction of CDK4/6 inhibitors, achieving survival gains in both endocrine-sensitive or endocrine-resistant populations. Despite the similar mechanism of action of the different CDK4/6 inhibitors, there are differences in the type, frequency, and severity of side-effects associated that merit evaluation. In addition, the endocrine partner could modulate the safety and tolerability profile of CDK4/6 inhibitors.

CDK4/6 inhibitors have dramatically changed the paradigm for the management of advanced breast cancer (ABC), prolonging patient survival and increasing number of women living with metastatic disease. Therefore, safety profile is of paramount importance when deciding the best treatment options for our patients” highlighted Dr. Llombart.

PARSIFAL trial compared the efficacy and safety of palbociclib with either letrozole or fulvestrant as initial treatment in postmenopausal women with endocrine-sensitive hormone receptor-positive/human epidermal growth factor receptor 2 (HR+/HER2–) advanced breast cancer (ABC). The trial involved researchers from 47 centers around 7 European countries (Czech Republic, France, Germany, Italy, Russia, Spain, United Kingdom). The safety data analyzed in this publication includes a total of 483 patients who received at least one dose of fulvestrant plus palbociclib (n = 241) or letrozole plus palbociclib (n = 242).

Results of this analysis altogether confirmed the favorable safety profile of both Palbociclib combinations. Grade ≥3 neutropenia was effectively managed with supportive medication and/or dose adjustment. Thromboembolic events and interstitial lung disease/pneumonitis were occasionally reported, and their early detection granted patients to effectively continue treatment without detriment to efficacy.

We would like to deeply thank patients and families who kindly participated in this study. Please contact us if you would like more information about the PARSIFAL trial.



bottom of page