Rituximab in the treatment of follicular lymphoma: the future of biosimilars in the evolving therapeutic landscape.

Follicular lymphoma (FL) is the second most common type of non-Hodgkin's lymphoma. FL is an incurable disease with treatment options ranging from a "watch-and-wait" approach to localized therapy with radiation or systemic therapy with rituximab in combination with chemotherapy regimens. This review summarizes the role of rituximab across the spectrum of FL treatment and the evolving therapeutic landscape with the emergence of novel agents currently in clinical development. Despite the prospect of new agents on the horizon, it is widely accepted that rituximab will remain as the cornerstone of therapy because of its established long-term efficacy. Many biologics, including rituximab, have lost exclusivity of composition-of-matter patent or will do so in the next few years, which is a concern for patients and physicians alike. Moreover, access to rituximab is challenging, particularly in countries with restricted resources. Together, these concerns have fueled the development of safe and effective biosimilars. The term "biosimilar" refers to a biologic product that is highly similar to an approved reference (or originator) product, notwithstanding minor differences in clinically inactive components, and for which there are no clinically meaningful differences in purity, potency, or safety. Biosimilars are developed to treat the same condition(s) using the same treatment regimens as an approved reference biologic, and have the potential to increase access to more affordable treatment of FL. Herein, we also discuss the potential benefits of eagerly awaited rituximab biosimilars, which may mitigate the impact of the lack of access to rituximab.