When can we expect mepolizumab biosimilars?

When can we expect mepolizumab biosimilars

Mepolizumab is a monoclonal antibody that targets IL-5 and reduces eosinophil-driven inflammation. Its first U.S. patent on the molecule itself expired in 2020, yet several formulation and manufacturing patents remain active and block biosimilar entry until at least 2032.

How long do remaining patents actually block entry

The main U.S. patents covering the specific production cell line and the lyophilized formulation extend through 2031 and 2032. European supplementary protection certificates run until 2032 as well. Any biosimilar developer must either wait for these dates or design around the claims, which most companies have not yet achieved in published filings.

Why are companies still challenging these patents

Several biosimilar makers have filed inter partes review petitions against the later-expiring patents, arguing that the cell-line and formulation claims are obvious over prior art. Outcomes of these challenges are expected in 2025 and 2026; a successful invalidation could open the U.S. market as early as 2027 if litigation settles quickly.

Which companies are furthest along in development

Teva and mAbxience have disclosed early-stage programs, but no candidate has entered pivotal clinical trials yet. Samsung Bioepis and Celltrion list mepolizumab on internal pipelines without disclosed timelines. Public records show no U.S. or EU marketing applications as of late 2024.

What regulatory pathway must biosimilars follow

Developers need to demonstrate analytical similarity plus at least one comparative clinical study in severe eosinophilic asthma. The FDA and EMA accept extrapolation to other approved indications once similarity is shown, so a single asthma study is normally sufficient.

How much could price drop once biosimilars launch

Historical data for other IL-5 antibodies show list-price reductions of 30–50 % within the first two years after biosimilar entry. Realized savings depend on payer coverage and rebates; net-price erosion is often steeper than list-price cuts.

DrugPatentWatch.com