Market Exclusivity for Drugs with Multiple Orphan Approvals (1983-2017) and Associated Budget Impact in the US.

Abstract

The Orphan Drug Act extends exclusivity of branded drugs by 7years for each rare disease approval. By extending market exclusivity, manufacturers can forestall generic competition. We determined the prevalence of drugs with multiple orphan approvals, the duration for which manufacturers are able to maintain exclusivity using this mechanism, and the budget impact of these additional exclusivity periods on US spending on orphan drugs. We analyzed a retrospective cohort of US orphan drug approvals filed between 1983 and 2017. Drug costs throughout this time period were measured using IQVIA claims data. We estimated additional years of exclusivity per drug per orphan approval using mixed-effects negative binomial regression. The budget impact analyzed potential cost-savings for exclusivity periods greater than 7years after the initial orphan approval based on potential price reductions from the introduction of biosimilar/generic competition. A total of 432 branded drugs were approved for 615 orphan indications, of which 108 had multiple indications. Market exclusivity, beyond the initial 7years, increased by 4.7years with two orphan approvals, and there were 3.1-, 2.7-, and 2.9-year extensions for three, four, and five approvals, respectively (p < 0.05). Drugs with five approvals averaged 13.4 additional years of exclusivity. Sixteen drugs had exclusivity periods extending at least 1 decade beyond the original exclusivity period. The potential budget impact of additional exclusivity was estimated at US$591 billion for 7years following the end of the first approval. Multiple blockbuster drugs have received exclusivity of > 10years through the Orphan Drug Act, thereby delaying rare disease cohorts' access to generic/biosimilar equivalents.