Current Status of Mopolizumab Generics
Mepolizumab, sold as Nucala by GlaxoSmithKline (GSK), treats severe eosinophilic asthma, eosinophilic granulomatosis with polyangiitis, and hypereosinophilic syndrome. No generic or biosimilar versions are available yet in the US, EU, or major markets. Patent protections and regulatory exclusivities block entry until at least the mid-2030s.[1][2]
Key US Patents and Expiry Dates
GSK holds multiple patents listed in the FDA's Orange Book for Nucala. The latest key composition-of-matter patent (US 8,435,521) expires February 22, 2035. Method-of-use patents extend further:
- US 9,290,484 (treatment method): May 23, 2033
- US 10,577,381 (asthma dosing): June 30, 2036
These dates assume no pediatric extensions or adjustments. Paragraph IV challenges from generic makers could shorten effective exclusivity via litigation, but none have succeeded yet.[2][3]
| Patent Number | Title/Description | Expiry Date |
|---------------|-------------------|-------------|
| US 8,435,521 | Anti-IL5 antibodies | Feb 22, 2035 |
| US 9,290,484 | Methods for reducing exacerbations | May 23, 2033 |
| US 10,577,381 | Subcutaneous dosing | Jun 30, 2036 |
FDA Exclusivities Beyond Patents
Nucala has orphan drug exclusivity until December 4, 2028, for hypereosinophilic syndrome, plus potential pediatric exclusivity adding six months. Biologic status under the BPCIA means biosimilars (not simple generics) require FDA approval after a 12-year reference product exclusivity from initial licensure (November 2015), ending November 2027. Even then, patents must clear first.[1][4]
Biosimilar Development and Challenges
Teva and Amgen have filed abbreviated biologics license applications (aBLAs) for mepolizumab biosimilars, triggering patent lawsuits with GSK. Teva's case (GSK v. Teva, Delaware District) is ongoing, with claim construction hearings in 2024. Settlement or court rulings could allow US launch by 2030 if early patents fall, but composition patents likely hold until 2035.[3][5]
Timeline in Europe and Other Markets
In the EU, EMA patent expiry aligns closely with the US; key EP 1,917,006 expires 2033-2035. No biosimilars approved; Biocon and Intas have applications under review, but launches unlikely before 2034.[6] Japan and Canada follow similar timelines, with generics trailing US/EU by 1-2 years.
Factors That Could Speed Up Availability
- Patent Settlements: GSK-Teva talks could mirror Keytruda deals, allowing at-risk launch post-2030.
- Litigation Wins: If challengers invalidate patents, biosimilars enter sooner (e.g., 2028 post-exclusivity).
- Supply or Policy Changes: Unlikely without FDA shortages or BPCIA reforms.
Patients face high costs ($13,000+ monthly US list price) until competition; assistance programs exist via GSK.[7]
Alternatives Available Now
Switch to dupilumab (Dupixent, Sanofi/Regeneron; patents to 2031+ but generics unlikely soon) or benralizumab (Fasenra, AstraZeneca; expiry ~2035). Pill options like tezepelumab are patented longer.[4]
Sources
[1] FDA Orange Book for Nucala
[2] DrugPatentWatch.com - Nucala Patents
[3] GSK v. Teva Litigation Tracker
[4] FDA Purple Book - Biologics
[5] Teva aBLA Announcement
[6] EMA Patent Register
[7] GSK Pricing Info