Which statement about biosimilar interchangeability is true?

• A. All biosimilars are automatically interchangeable with reference products.
• B. A biosimilar must prove it would have the same clinical effect to be considered interchangeable.
• C. Biosimilars are never interchangeable with reference products.
• D. Interchangeability is determined by the manufacturer without testing.

Answer: (B)

Interchangeability requires extra evidence beyond biosimilarity: a biosimilar must demonstrate it would produce the same clinical effect as the reference product in patients, and that switching between the biosimilar and the reference product does not increase risk or affect efficacy. Because of this additional data requirement, not all biosimilars are interchangeable, and interchangeability is an FDA designation, not a default status granted by the manufacturer. The other statements misstate the process: substitution isn’t automatic, biosimilars aren’t never interchangeable, and the designation isn’t made without testing.