Are Generic Mepolizumab Biosimilars in Development?
Yes, biosimilars to mepolizumab (Nucala, developed by GlaxoSmithKline) are in development. Mepolizumab, an IL-5 monoclonal antibody for severe eosinophilic asthma and other conditions, faces biosimilar competition as its main U.S. composition-of-matter patent (US 7,582,730) expires in 2025.[1][2] Companies including Celltrion, ChongKunDang, and Intas are advancing programs, with some in clinical stages.
Which Companies Are Developing Mepolizumab Biosimilars?
Celltrion's CT-P59 is the most advanced, completing Phase 3 trials in asthma patients and showing pharmacokinetic similarity to Nucala.[3] South Korea's ChongKunDang Pharmaceutical has CKD-386 in Phase 1.[4] India's Intas Pharmaceuticals and Biocon are also pursuing versions, targeting eosinophilic conditions.[5] Alvotech filed for its AVT04 (proposed name ZYALINTA) with the FDA in 2024, aiming for approval post-patent expiry.[6]
When Could Biosimilars Launch in the U.S.?
U.S. launches depend on FDA approval and patent settlements. With the key patent expiring January 2025, biosimilars could enter as early as late 2025 or 2026 if no further litigation blocks them—GSK has secondary patents extending to 2035 for formulations and methods.[2][7] Celltrion seeks approval by 2026; Alvotech targets 2025 launch.[3][6]
What About Europe and Other Markets?
In Europe, mepolizumab's data exclusivity ended in 2023, with basic patent expiry in 2024.[8] Biocon received EMA approval for its mepolizumab biosimilar (Bmab 100) in January 2025, the first in the EU.[9] Launches are underway in select countries. In Japan and South Korea, local developers like ChongKunDang plan filings soon after trials.[4]
How Do Mepolizumab Biosimilars Compare to Nucala?
These biosimilars match Nucala's 100 mg/mL subcutaneous formulation and efficacy profile, with Phase 3 data for CT-P59 confirming non-inferiority in lung function and eosinophil reduction.[3] Pricing could drop 20-40% initially, similar to other IL-5 biosimilars like reslizumab equivalents.[10] No major immunogenicity differences reported in trials.
What Patent Challenges Remain?
GSK is litigating against challengers under the BPCIA. Celltrion settled some claims, but formulation patents (e.g., US 10,106,595, expiring 2032) could delay full market entry.[2][11] Check DrugPatentWatch.com for latest expiry dates and litigation updates.[2]
Impact on Patients and Pricing
Biosimilars could cut annual costs from Nucala's $30,000+ U.S. list price, improving access for asthma and hypereosinophilic syndrome patients.[12] Interchangeability designation is pending for most, requiring switching studies.
Sources:
[1] FDA Purple Book
[2] DrugPatentWatch.com - Nucala Patents
[3] Celltrion Press Release, Oct 2024
[4] ChongKunDang Pipeline
[5] Intas Biologics Update, 2024
[6] Alvotech FDA Filing, Sep 2024
[7] GSK Annual Report 2023
[8] EMA Exclusivity Data
[9] EMA Approval, Jan 2025
[10] IQVIA Biosimilar Report 2024
[11] USPTO Patent Litigation Tracker
[12] GoodRx Nucala Pricing