EPIDIOLEX and FINTEPLA in 2026: Commercial Anchors in a Precision DEE Pipeline

Developmental and epileptic encephalopathies (DEEs) have evolved from symptom control toward precision neurology, with the market anchored by EPIDIOLEX (cannabidiol, Jazz Pharmaceuticals), initially approved in the US in 2018 for Dravet syndrome and Lennox–Gastaut syndrome (LGS) and later expanded to tuberous sclerosis complex (TSC) in 2020, and FINTEPLA (fenfluramine, UCB), approved for Dravet syndrome in 2020 and LGS in 2022. The market has further expanded with ZTALMY (ganaxolone, Marinus Pharmaceuticals), approved in 2022 as the first therapy specifically indicated for CDKL5 deficiency disorder, reinforcing the shift toward mechanism-based and syndrome-specific treatment. Looking ahead, antisense oligonucleotides, gene-based therapies, and targeted small molecules are expected to further transform the DEE treatment landscape.

EPIDIOLEX and FINTEPLA are locking horns in the rare DEE segment, with EPIDIOLEX currently leading in terms of sales. The unexpectedly strong uptake and high sales of EPIDIOLEX are mainly due to the first-mover advantage of a novel class in this space, which only had antiepileptic drugs (AEDs) used in combination. EPIDIOLEX achieved blockbuster status in 2025, with net product sales of approximately USD 1.1 billion, reflecting 9% year-over-year growth from 2024. By contrast, FINTEPLA is far behind, with global revenues rising 50% to USD 368 million in 2024 and further increasing to USD 483 million in 2025. FINTEPLA continues to trail EPIDIOLEX owing to its later market entry, a narrower initial label limited to Dravet syndrome, and comparatively shorter physician experience and market penetration. 

Looking ahead, FINTEPLA is expected to strengthen its competitive position by expanding into CDD following positive Phase III results. In contrast, while EPIDIOLEX continues to benefit from orphan drug exclusivity for LGS and Dravet syndrome through September 2025 and for TSC through July 2027, its growth is expected to moderate as the product approaches market maturity. 

Better Efficacy: EPIDIOLEX or FINTEPLA? 

Among EPIDIOLEX and FINTEPLA, both drugs have significant overall efficacy and safety; however, when comparing their efficacy in Dravet syndrome, FINTEPLA’s response rate was 4 times higher, and in LGS, it was 3 times higher than placebo. In contrast, EPIDIOLEX reduced the seizure frequency by three times for Dravet syndrome and by two times for LGS compared to placebo. Also, the efficacy numbers for FINTEPLA were lower in LGS than in Dravet syndrome, with a 60%+ reduction. Thus, FINTEPLA beats EPIDIOLEX in terms of efficacy, and we believe that FINTEPLA’s efficacy in Dravet patients is much higher than that of those suffering from LGS.

Commercial Expansion Beyond the US

The European DEE treatment market has become increasingly favorable for both EPIDIOLEX (EPIDYOLEX in Europe) and FINTEPLA, although reimbursement negotiations continue to shape the pace of commercial uptake in individual countries. EPIDYOLEX has established a broad commercial presence across major European markets following its EU approval in 2019 and subsequent reimbursement agreements, while FINTEPLA has also expanded steadily after receiving approvals for Dravet syndrome and LGS. Nevertheless, differences in national pricing and reimbursement frameworks continue to create variability in market access and adoption across Europe.

In Japan, FINTEPLA has significantly strengthened its position, securing approvals for Dravet syndrome (2022) and LGS (2024) through UCB’s partnership with Nippon Shinyaku, providing access across both of its major approved indications. In contrast, EPIDIOLEX remains unapproved in Japan following its 2024 Phase III trial, which failed to meet the primary efficacy endpoint. However, numerical improvements in seizure outcomes and a favorable safety profile have prompted Jazz Pharmaceuticals to continue pursuing regulatory approval in collaboration with Nippon Zoki Pharmaceutical.

The Next Wave of Competition in the DEE Market

The investigational landscape includes several emerging DEE therapies with differentiated mechanisms of action and targeted approaches. Key pipeline candidates include Relutrigine (Praxis Precision Medicines), Bexicaserin (Longboard Pharmaceuticals/Lundbeck), Zorevunersen (Stoke Therapeutics), Apazunersen (Ultragenyx Pharmaceutical), Elsunersen (Praxis Precision Medicines), EPX-100 (Harmony Biosciences), Rugonersen (Oak Hill Bio/Roche), as well as additional assets such as Carisbamate (SK Life Science), Obudanersen (Ionis Pharmaceuticals), BMB-101 (Bright Minds Biosciences), YCJ-01 (Oils4Cure), Tricaprilin (Cerecin Neurosciences), and others. These therapies reflect increasing emphasis on precision medicine, genetic targeting, and novel pharmacological pathways.

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