# Drop the extra switching studies for interchangeable oncology biosimilars

Source: https://onco.cc/ideas/idea-cost-interchangeable-oncology-biosimilars/  
OnCo record `idea-cost-interchangeable-oncology-biosimilars` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

US law lets a pharmacist swap an 'interchangeable' biosimilar without asking the prescriber, but earning that label used to need costly switching studies; the FDA now says those are usually unnecessary, which should be made permanent for cancer antibodies.

## Summary

Interchangeability is a US-only regulatory status that allows pharmacy-level substitution. Historically it required dedicated switching studies, which delayed and added cost to biosimilar programmes. In 2024 the FDA issued draft guidance stating that switching studies are generally not needed to demonstrate interchangeability. Finalising that position and applying it to the oncology antibodies would remove a barrier to automatic substitution in the 40-plus states whose pharmacy laws recognise the status.

## Fields

- Kind: Idea
- Last checked: 2026-09-10
- Hypothesis: Interchangeable designation for oncology biosimilars without switching studies will bring at least three interchangeable cancer antibodies to market within three years and raise substitution rates in states with pharmacy substitution laws.
- Rationale: European regulators regard all approved biosimilars as interchangeable and have a decade of switching data without safety signals.
- Proposed test: Track interchangeable designations, time to designation and biosimilar share in oncology before and after the guidance is finalised.
- Maturity: early-clinical
- Actor: regulator

## Sources

- FDA: Biosimilars: https://www.fda.gov/drugs/therapeutic-biologics-applications-bla/biosimilars

## Connected records

- institutions: [European Medicines Agency](https://onco.cc/institutions/ema/), [FDA Oncology Center of Excellence](https://onco.cc/institutions/fda-oce/)
- terms: [Biosimilar](https://onco.cc/terms/biosimilar/)
- bottlenecks: [Prices and value](https://onco.cc/bottlenecks/b-drug-pricing/), [Regulatory divergence between regions](https://onco.cc/bottlenecks/b-regulatory-fragmentation/)

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