Biosimilars Guide

Biosimilars are biologic products that are highly similar to an already-approved reference biologic, with no clinically meaningful differences in safety, purity, or potency. They represent the most significant cost-reduction opportunity in specialty pharmacy, with price discounts typically ranging from 30-60% below the reference product.

FDA Approval Pathways

The FDA approves biosimilars through an abbreviated pathway established by the Biologics Price Competition and Innovation Act (BPCI Act). Manufacturers must demonstrate biosimilarity through analytical, animal, and clinical studies. An additional designation of interchangeability can be granted, allowing pharmacists to substitute the biosimilar for the reference product without prescriber intervention, similar to generic drug substitution.

Current Biosimilar Market

The U.S. biosimilar market has expanded significantly with the launch of biosimilars for adalimumab (Humira), bevacizumab (Avastin), trastuzumab (Herceptin), infliximab (Remicade), and several other high-cost biologics. Humira biosimilars, which launched in 2023, represent the largest commercial opportunity due to Humira's position as the best-selling drug in history.

Adoption Barriers

Despite significant price advantages, biosimilar adoption in the United States has been slower than in Europe, where biosimilars routinely capture 50-80% of reference product volume within a few years. U.S. barriers include PBM rebate relationships with reference product manufacturers (where rebates on the original may exceed the net savings from switching to a biosimilar), prescriber and patient unfamiliarity, and legal challenges from reference product manufacturers.