Dose variation in metastatic breast cancer: Are European Medicines Agency summary of product characteristics (SmPC) being followed?

Abstract

e11581 Background: Breast cancer represents the highest cancer burden in the EU and is a high profile treatment area. We identify variation in treatment length and dosing of bevacizumab (BV) and capecitabine (CP) in France, Germany, Italy, Spain and UK (EU5) compared to European Medicines Agency (EMA) SmPC dosing recommendations for metastatic breast cancer (mBC). Methods: This study used IMS Oncology Analyzer, an anonymised patient database collected through quarterly physician panel survey, which provides information on patterns of cancer care. Inclusion criteria of mBC patients currently receiving BV or CP collected within the last 3 years (October 2011 – September 2014). Correct dosing defined as (+/- 10%): BP – 10 mg/kg over 2 weeks or 15 mg/kg over 3 weeks; CP – 1,250 mg/m2 over 2 weeks with 1 week rest. Results: 84% (513/612) of BV patients received correct cycle length, with 77% of these patients (397) dosed correctly. 97 patients (19%) were under dosed with less than half over 60 years old and 70% presenting with an ECOG score of 1-2. While the remaining 16% of BV patients did not receive the recommended cycle length, 82% (81/99) did receive either 10 or 15 mg/kg EMA recommended doses. Although 90% of CP treated patients (619/686) received the correct cycle length, only 23% of those patients were dosed at the recommended 1,250 mg/m2. 60% (372/619) were under dosed; of which 70% are over 60 years old and 83% presented with an ECOG status of 1-2, with 244 patients receiving 1,000 mg/m2. While this dosage is commonly prescribed in combination in colorectal and gastric cancer, panel physicians were of the opinion that lower doses in mBC have similar efficacy and reported reducing doses to increase tolerability, as supported by the proportion of over 60 year olds being under dosed in the data. Conclusions: This study has identified variation in dosing and cycle duration of both BV and CV from those recommended by the EMA. It therefore appears that physicians are actively tailoring dosage and cycle length to patients’ fitness as opposed to strictly following EMA SmPC.