{"entity":{"id":"idea-cost-biosimilar-default-substitution","kind":"idea","name":"Make the biosimilar the default at the pharmacy for trastuzumab, bevacizumab and rituximab","aka":[],"tldr":"Copies of the big antibody drugs are approved and cheaper, but uptake depends on each prescriber; letting the pharmacy substitute the biosimilar unless the oncologist objects would move most patients within a year.","summary":"FDA-approved biosimilars of trastuzumab, bevacizumab, rituximab and pegfilgrastim have been on the US market since 2019. IQVIA estimated that biosimilars saved $56 billion over the decade to 2022 and projected $181 billion more over 2023 to 2027. Uptake still varies widely by practice because substitution requires a prescriber decision, a payer preference and a purchasing contract to line up. A default-substitution rule (opt-out rather than opt-in), combined with the flat-fee payment idea, removes the friction. NHS England and several European systems achieved over 90% uptake this way.","asOf":"2026-09-10","links":[{"label":"IQVIA Institute: Biosimilars in the United States 2023-2027 (January 2023)","url":"https://www.iqvia.com/insights/the-iqvia-institute/reports-and-publications/reports/biosimilars-in-the-united-states-2023-2027"},{"label":"FDA: Biosimilars","url":"https://www.fda.gov/drugs/therapeutic-biologics-applications-bla/biosimilars"}],"tags":[],"related":[],"cancers":[],"sections":[],"technologies":[],"targets":[],"drugs":["trastuzumab","trastuzumab-biosimilars","bevacizumab","rituximab"],"companies":[],"institutions":[],"pathways":[],"terms":["biosimilar"],"trials":[],"people":[],"bottlenecks":["b-drug-pricing","b-knowledge-diffusion"],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"Default substitution in a payer's network will lift biosimilar share for the three antibodies above 85% within twelve months, from a baseline that varies between 40% and 80%.","rationale":"Biosimilars have no clinically meaningful difference by regulatory definition; the remaining barrier is process, not evidence.","test":"A payer-level stepped rollout across regions with biosimilar share, drug spend and any switch-related adverse events reported quarterly.","maturity":"being-tested-at-scale","actor":"payer","cost":"small","horizonYears":2},"route":"/ideas/idea-cost-biosimilar-default-substitution/","neighbours":{"drug":[{"id":"bevacizumab","kind":"drug","name":"Bevacizumab","route":"/drugs/bevacizumab/"},{"id":"rituximab","kind":"drug","name":"Rituximab","route":"/drugs/rituximab/"},{"id":"trastuzumab","kind":"drug","name":"Trastuzumab","route":"/drugs/trastuzumab/"},{"id":"trastuzumab-biosimilars","kind":"drug","name":"Trastuzumab biosimilars","route":"/drugs/trastuzumab-biosimilars/"}],"term":[{"id":"biosimilar","kind":"term","name":"Biosimilar","route":"/terms/biosimilar/"}],"bottleneck":[{"id":"b-knowledge-diffusion","kind":"bottleneck","name":"Knowledge reaches practice too slowly","route":"/bottlenecks/b-knowledge-diffusion/"},{"id":"b-drug-pricing","kind":"bottleneck","name":"Prices and value","route":"/bottlenecks/b-drug-pricing/"}]}}