Lupin Limited has received final approval from the United States Food and Drug Administration (USFDA) for its generic Amifampridine Tablets, 10 mg, a treatment for the rare autoimmune disorder Lambert-Eaton myasthenic syndrome (LEMS). The Mumbai-based drugmaker announced the approval on 2 November 2026 and said that, as one of the first applicants to file, it is eligible for 180 days of shared generic exclusivity in the US.

The nod adds a rare-disease neurology product to Lupin’s US generics pipeline, months after Lupin secured a USFDA tentative approval for Pitolisant tablets to expand its central nervous system (CNS) portfolio.

Key takeaways

• The USFDA approved Lupin’s Abbreviated New Drug Application (ANDA) for Amifampridine Tablets, 10 mg, on 2 November 2026.
• The tablets are bioequivalent to Firdapse Tablets, 10 mg, of Catalyst Pharmaceuticals, which reported Firdapse net sales of about $358 million in 2025.
• Lupin is a first-to-file applicant and is eligible for 180 days of shared generic exclusivity.
• Under a 2025 patent settlement with Catalyst, Lupin will not market the generic in the US before 25 February 2035, barring limited customary exceptions.

What the Lupin amifampridine approval covers

According to Lupin’s press release, the approved Amifampridine Tablets, 10 mg, are bioequivalent to the reference listed drug Firdapse Tablets, 10 mg, for the indication in the approved labelling. Firdapse is a registered trademark of SERB S.A. and is marketed in the US by Catalyst Pharmaceuticals.

When the product received USFDA tentative approval on 17 March 2025, Lupin said it is indicated for LEMS in adults and in children aged 6 years and older, and that it would be manufactured at the company’s Goa facility in India.

Why LEMS treatment matters

LEMS is a rare autoimmune condition in which the communication between nerves and muscles is disrupted, causing muscle weakness. Amifampridine, a potassium channel blocker, is the active ingredient in Firdapse, which BioSpace describes as the only USFDA-approved treatment for the disease. ET Pharma, citing Catalyst’s annual financial statement, reported that Firdapse posted net sales of $358 million in 2025.

Rare-disease therapies remain a niche but closely watched area for Indian drugmakers and policymakers, as seen in efforts such as NHM Madhya Pradesh’s partnership with Sanofi India on rare disease care.

Exclusivity and launch timeline

The 180-day exclusivity is shared, which means other first-filers may also benefit from the same window. The launch timing, however, is governed by Lupin’s earlier patent settlement. In August 2025, Catalyst announced a settlement with Lupin under which Lupin will not market its generic Firdapse in the US earlier than 25 February 2035, unless certain limited circumstances customary in such agreements occur. Catalyst had earlier settled similar ANDA litigation with Teva Pharmaceuticals and Inventia Healthcare.

Lupin’s 2 November announcement did not give a launch date for the product.

Goa plant and regulatory track record

Lupin’s Goa facility received an Establishment Inspection Report with a Voluntary Action Indicated (VAI) classification in February 2026, after a USFDA inspection held from 10 to 21 November 2025, CNBC-TV18 reported. Regulatory compliance at Indian plants remains under scrutiny, with India Ratings flagging serious lapses in 17% of USFDA inspections at Indian drug plants.

The approval also comes in a busy week for Indian generics in the US, after Dr Reddy’s won a USFDA tentative approval for lenacapavir. Lupin filed the announcement with the stock exchanges after market hours on 2 November 2026; its shares had closed at ₹1,996.55 on the BSE that day, down 0.62%.

Frequently asked questions

What did the USFDA approve for Lupin?

The USFDA approved Lupin’s ANDA for Amifampridine Tablets, 10 mg, a generic version of Catalyst Pharmaceuticals’ Firdapse, on 2 November 2026.

What is amifampridine used for?

Amifampridine is used to treat Lambert-Eaton myasthenic syndrome, a rare autoimmune disorder that causes muscle weakness, in adults and children aged 6 and older.

When can Lupin launch generic amifampridine in the US?

Under its 2025 settlement with Catalyst, Lupin will not market the product in the US before 25 February 2035, except in certain limited circumstances.

Featured image: Lupin’s manufacturing facility in Goa, India. Photo: Lupin Limited

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