Patent/carglumic acid?

Carglumic Acid (Carbaglu®)

• What it is – A synthetic analogue of N‑acetyl‑glutamate (NAG) that activates carbamoyl‑phosphate synthetase‑1 (CPS‑1), the first enzyme of the urea cycle.
• Uses – Approved for acute and maintenance treatment of hyperammonemia in patients with propionic acidemia and methylmalonic acidemia (the “propionic/methylmalonic aciduria” (PMA) disorders).
• Formulation – Oral tablets (15 mg, 30 mg, 45 mg, 60 mg).
• Brand name – Carbaglu® (Astellas).

1. Why patents matter for carglumic acid

• Commercial exclusivity: Patents give the sponsor exclusive rights to manufacture, sell, and market the drug for a period of 20 years from the filing date, subject to maintenance fees.
• Generic entry: Once the patents expire (or are invalidated/assigned), other manufacturers can produce a generic version, usually at a lower cost.

2. Key patents (and their status)

Notes:

• Patent 5,498,842 (the original composition patent) expired in 2017.
• Patent 6,214,613 (the original method patent) expired in 2021.
• Patent 7,060,991 (a secondary method patent) expired in 2022.
• The most recent “method” patent (WO 2005/004302) expired in early 2024.
• US 2006/0045205 is a “utility” (pre‑publication) application; because no maintenance fee was paid, it is presumed lapsed in 2026.

Thus, all primary patents that gave Astellas exclusive rights to carglumic acid have expired. The drug is now in the “generic‑entry” phase in many markets.

3. Generic availability

Generic versions contain the same active ingredient (carglumic acid) in the same dosage forms (15 mg–60 mg tablets) and are bioequivalent to Carbaglu®.

4. How to check current patent status

1. USPTO Patent Full-Text and Image Database (PatFT) – search by “carglumic acid” or the applicant “Astellas” to see all filings and their status.
2. European Patent Office (EPO) Espacenet – enter the “Carglumic Acid” keyword.
3. WIPO PATENTSCOPE – for international applications.
4. DrugPatentWatch – a subscription service that tracks drug patent expirations and generic entry dates.

5. Why the patents were important

• First‑in‑class: Carglumic acid was the first oral drug that specifically activated the urea cycle.
• High cost of development: The drug required extensive metabolic studies and clinical trials in rare‑disease populations.
• Exclusivity period: The 20‑year exclusivity allowed Astellas to recoup R&D investment and provide a dedicated treatment for a life‑threatening metabolic disorder.

6. Quick FAQ

Bottom line

Carglumic acid’s main patents have all expired, allowing a wave of generic competitors. The drug continues to be a cornerstone therapy for patients with propionic/methylmalonic aciduria, and the lower cost of generics is expanding access worldwide. If you’re a prescriber or patient, it’s worth checking the specific generic status in your country and confirming insurance coverage.