Biosimilars in rare diseases: a focus on paroxysmal nocturnal hemoglobinuria

Biologics, a class of medicines grown in and purified from genetically engineered cell cultures, have transformed the management of many cancers and rare diseases, such as paroxysmal nocturnal hemoglobinuria. As prescription drug spending has increased and exclusivity periods have expired, manufacturers have developed biosimilars–biologics that may be more affordable and highly similar to a licensed biological therapeutic, with no clinically meaningful differences in terms of safety or efficacy. With biosimilars gaining regulatory approval around the globe and broadening patient access to biologics, this review aims to help rare disease healthcare providers familiarize themselves with biosimilars, understand their development and regulatory approval process, and address practical considerations that may facilitate their use.