Sun Pharma Receives FDA Approval for Generic Perampanel (Fycompa), Targeting USD 18 Billion Epilepsy Market
Background of ANDA Approval
Sun Pharmaceutical Industries (NSE: SUNPHARMA) has received approval from the U.S. FDA for its Abbreviated New Drug Application (ANDA) for a generic version of Eisai's (4523.T) anti-epileptic drug, Fycompa (perampanel). Perampanel is the first non-competitive selective AMPA glutamate receptor antagonist, indicated for focal-onset seizures and primary generalized tonic-clonic (PGTC) seizures, and is classified as a Schedule III controlled substance. Teva secured the first generic approval in May 2025, and Sun Pharma is entering the market with a subsequent generic version.
Erosion of Brand Sales and Impact of LOE
Eisai transferred the U.S. commercial rights for Fycompa to Catalyst Pharmaceuticals (NASDAQ: CPRX) in 2022, with annual net sales in the U.S. at approximately USD 136 million at the time of the transfer. Following the patent expiration (Loss of Exclusivity, LOE) in 2025, generic competition intensified, and Catalyst's Fycompa sales decreased sharply to USD 13.8 million in Q1 2026, a 61.3% year-over-year decline. Sun Pharma's additional entry is expected to further accelerate this brand erosion.
Competitive Landscape of Anti-Epileptic Drugs
The global anti-epileptic drug (AED) market is approximately USD 18 billion in 2025, with North America accounting for 48%, and is projected to reach USD 30.8 billion in 2035 with an annual growth rate of 5.5%. While perampanel has a unique mechanism of action as an AMPA receptor antagonist, it competes with levetiracetam (Keppra generic) and brivaracetam (Briviact), which are SV2A ligands, lacosamide (Vimpat), a sodium channel blocker, and cenobamate (Xcopri), which has a multi-target mechanism. Cenobamate has demonstrated superior efficacy with a seizure freedom rate of 19.5% compared to 8.3% for competing drugs, and is increasing its market share.
Sun Pharma's Strategic Context
Sun Pharma is one of the world's largest generic companies, with 552 ANDA approvals in the U.S., and U.S. sales of USD 1.9 billion in FY2026. However, the U.S. generic business experienced a year-over-year decline of 0.9% due to price pressures, and the strategic focus is shifting as innovative drug sales exceeded USD 1 billion for the first time. The perampanel generic is a portfolio expansion that strengthens Sun Pharma's existing CNS generic product line.
Future Developments
Catalyst is scheduled to be acquired by Angelini Pharma for approximately USD 4.1 billion, with the transaction expected to close in Q3 2026. Given the sharp decline in Fycompa sales, Angelini is likely to focus on its rare disease portfolio (Firdapse, Agamree). Increased generic competition will improve patient access, and prices may fall by approximately 50% compared to the branded product.
In the global AED market of USD 18 billion, the generic transition of Fycompa following LOE is accelerating, and with Teva's entry followed by Sun Pharma, Catalyst's (CPRX) Fycompa sales have already decreased by 61.3% year-over-year to USD 13.8 million in Q1 2026. While perampanel has a unique mechanism of action as the only AMPA receptor antagonist, securing a market share in the generic market is crucial, given the superior seizure freedom rate of 19.5% for cenobamate (Xcopri) and the price competitiveness of levetiracetam generics. For Sun Pharma, adding a CNS product to its portfolio of 552 ANDAs represents a gradual contribution to revenue, but it is not sufficient to reverse the trend of a 0.9% year-over-year decline in the U.S. generic business in FY2026. Angelini's acquisition of Catalyst (USD 4.1 billion) is expected to close in Q3 2026, and the structural decline in Fycompa's brand value will likely further accelerate the reorganization of the portfolio towards a focus on rare diseases.
Source: openFDA (api_fda)
https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=ANDA219052