Access to orphan drugs in adults with inherited metabolic diseases in Switzerland: a single-center retrospective cohort study

BACKGROUND: Orphan drugs (ODs) are increasingly used to treat rare diseases, including inherited metabolic diseases (IMDs), but real-world access remains insufficiently characterized. This study aimed to evaluate access to ODs in adults with IMDs treated at a Swiss reference center and to analyze the associated regulatory and reimbursement frameworks. METHODS: In this retrospective, single-center study conducted between 2017 and 2022, we included all adult patients with a confirmed biochemical and/or genetic diagnosis of an IMD who received an OD. The primary outcome was the proportion of patients receiving OD therapy. Secondary outcomes included the types of ODs used, reimbursement procedures, time from treatment indication to treatment initiation, timelines in Swiss marketing authorization (MA) and reimbursement compared with international benchmarks. RESULTS: Of 190 patients followed, 41 (21.6%) had an indication for OD therapy and 39 (20.5%) received treatment (median age 30.3 years, range 19-65). Seventeen different ODs were prescribed. The median time from treatment indication to treatment initiation was 1.0 month [IQR 0.6-2.6] but was longer for drugs without Swiss MA (Art. 71c OAMal: 6.5 months [IQR 2.5-11.9]). Swissmedic MA occurred a median of 1.9 years [IQR 1.5-2.7] after approval by other international regulators. Three patients were the first adults in Switzerland to access novel substances (olipudase alfa, pegvaliase, metreleptin), and one received the newly approved formulation of nitisinone. CONCLUSION: In this cohort from a specialized adult metabolic clinic, most patients with an indication for OD therapy accessed treatment. However, administrative burden, fragmented reimbursement procedures, and regulatory delays may still affect timely treatment initiation in certain situations. These findings highlight the need for continued efforts to streamline regulatory and reimbursement pathways and to ensure equitable access to innovative therapies for rare diseases. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05818566, registered 18 April 2023.