The aim of this study was to identify trends in deficiencies raised during the EU evaluation of the quality part of dossiers for marketing authorisation applications of biosimilar medicinal products. All adopted day 120 list of questions on the quality module of 22 marketing authorisation applications for biosimilars submitted to the European Medicines Agency and concluded by the end of October 2015 was analysed. Frequencies of common deficiencies identified were calculated and summarised descriptions included. Frequencies and trends on quality deficiencies were recorded and presented for 22 biosimilar applications. Thirty-two 'major objections' for 9 products were identified from 14 marketing authorisation applications with 15 raised for drug substance and 17 for drug product. In addition, 547 'other concerns' for drug substance and 495 for drug product were also adopted. The frequencies and trends of the identified deficiencies together with their impact were discussed from a regulatory perspective and how these impact key manufacturing processes and key materials used in the production of biosimilars. This study provides an insight to the regulatory challenges prospective companies need to consider when developing biosimilars; it also helps elucidate common pitfalls in the development and production of biosimilars and in the submission of dossiers for their marketing authorisations. The results are expected to be of interest to pharmaceutical companies but also to regulators to obtain consistent information on medicinal products based on transparent rules safeguarding the necessary pharmaceutical quality of medicinal products.
Keywords: biosimilars; chemistry manufacturing control; deficiencies; marketing authorisations; pharmaceutical development.