Preface

We live in an era of great advances in health biotechnology, one of which is the development of biological medicines. These were introduced in the 1980s and have since become important tools in modern medicine. The clinical advances provided by biological medicines have helped clinicians to better manage chronic diseases such as rheumatoid arthritis, spondyloarthritis, psoriasis, diabetes, and Crohn's disease as well as some types of cancer and rare diseases. However, the introduction of biologics has increased health expenditures, greatly affecting the healthcare budgets of both underdeveloped and developed countries. Fortunately, about two decades ago, biosimilars came to the market as more affordable options for patients treated with biologics. As highly similar, equivalent, and less expensive than their reference products, biosimilars have provided competition in the market and have expanded patient access to biological therapies.

Biosimilars are linked to regulatory advances, health policies, market opportunities, and great financial investments from the pharmaceutical industry. Curiously, not only did the robust approval process of biosimilars lead to the great acceptance of such biologic products, but also real-world evidence and data have contributed to reassuring physicians and patients about the efficacy and safety of biosimilars compared to their reference products. Most importantly, health professionals have come to realize how important biosimilars are to the sustainability of health systems.

As the market for biosimilars continues to expand and the number of biosimilar products for each approved biological reference product increases, the likelihood of patients needing to switch from one biosimilar to another, for whatever reason, is also expected to increase. Several real-world scenarios, of a medical and non-medical nature, may lead to cross-switching between biosimilars of the same reference product.

This book reviews and summarizes the most important topics related to biosimilars to help physicians adopt the best approach to treatment decision-making.

We wish you a pleasant and enlightening read!

**Valderilio Feijó Azevedo** Hospital de Clínicas Universidade Federal do Paraná, Curitiba, Brazil

> **Robert Moots** University of Liverpool, Liverpool, United Kingdom

### **Chapter 1**
