Extrapolation of indications for medicines refers to the practice of extending the approved use of a medication beyond the specific population or condition studied during the drug development process. It involves using data from studies conducted in one population or condition to support the approval of the medication for other populations or conditions. This approach is common in regulatory decision-making for both small molecule drugs and biologics, including biosimilars.
Extrapolation of indications can only be allowed if scientifically justified
A reference biologic product can be approved for several indications. A biosimilar product should be extrapolated to other indications of the reference product without having to duplicate trials if:
- High molecular similarity between the biosimilar and reference product has been demonstrated
- The biosimilar has been shown to be of equivalent safety and efficacy to the reference product in one indication that is sensitive to demonstrating any potential differences.
- The indication for which the biosimilar has established equivalent safety and efficacy shares the same clinical mode-of-action with the indications for which the extrapolation is sought.
Appropriate extrapolation under these circumstances prevents unnecessary duplication of clinical studies in humans and ensures economically sustainable development of biosimilars.