• Phase 3 CDKL5 deficiency disorder (CDD) results: UCB shares 21 scientific abstracts, including the presentation of positive primary efficacy and safety results from a phase 3 study of FINTEPLA^® (fenfluramine)¹ in CDD, marking the third developmental and epileptic encephalopathy (DEE) to see positive results following Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS).²
• Open-label extension study for fenfluramine: Sustained long-term safety and clinical benefit, as assessed by investigator- and caregiver-reported Clinical Global Impression-Improvement (CGI-I) ratings, in patients living with DS and LGS.³
• Developmental and epileptic encephalopathies survey: Interim caregiver survey data highlight the significant impact of disruptive seizures on individuals living with DEEs and their caregivers, emphasizing the importance of support for families managing DEEs⁴
• Prolonged seizures: Studies underscore the significant burden and risks of prolonged seizures, highlighting the need for swift intervention and improved treatment options to prevent escalation and enhance outcomes.^5,6,7,8

ATLANTA, Dec. 4, 2025 /PRNewswire/ -- UCB, a global biopharmaceutical company, today announced it will present 21 abstracts at the American Epilepsy Society (AES) Annual Meeting (December 5-9, 2025). Data include primary efficacy and safety results from a Phase 3 study of fenfluramine in CDD, final results from a long-term, open-label extension study of fenfluramine in DS and LGS, findings on the disease burden of developmental and epileptic encephalopathies (DEEs), and research on prolonged seizures.^{2,3,4,5,6,7,8}

Dimitrios Bourikas, Global Medical Head, DEE and Epilepsy, UCB, commented: "Sharing these new data at AES 2025 reflects UCB's unwavering dedication to addressing the needs of people living with epilepsy and those who support them. By highlighting clinical outcomes and the experiences of patients and caregivers, we hope to inform better care and support, with the ultimate goal of creating a future where nobody facing a debilitating epileptic condition is left behind."

Highlights of data to be presented at AES 2025:

Fenfluramine in CDKL5 deficiency disorder: Primary positive phase 3 results^2*
A phase 3, randomized, placebo-controlled trial shows that fenfluramine provided significantly greater reduction in countable motor seizure frequency compared with placebo in patients with CDKL5 deficiency disorder. Treatment emergent adverse events (TEAEs) are consistent with the known safety profile of fenfluramine in DS and LGS.

*The safety and efficacy of fenfluramine for the treatment of CDD has not been established and is not currently approved for use by any regulatory authority worldwide. In the US, FINTEPLA (fenfluramine) is indicated for the treatment of seizures associated with DS and LGS in patients 2 years of age and older.¹

Final results from a long-term open-label extension study of fenfluramine (up to 4 years)³
These data show a consistent rate of TEAEs with previous DS and LGS Phase 3 studies, as well as an improvement or no change in CGI-I ratings from baseline by caregivers and investigators.

Impact of disruptive seizures on daily functioning⁴
Interim results from a large caregiver survey highlight that disruptive seizures, sleep disturbances, and challenging behaviors from those living with DEEs have a substantial impact on both activities of daily living and the ability to communicate. The data underscore the ongoing burden on individuals living with DEEs and their caregivers, emphasizing the need for holistic support and care strategies.

Prolonged seizures

• Real-world study of patients in the United States highlight that those experiencing prolonged seizures are at an increased risk for serious complications, including progression to status epilepticus and a frequent need for emergency healthcare.⁵ 
• Interviews with patients and caregivers indicate a clear preference for acute seizure medications that can be administered quickly and act rapidly at seizure onset.7 A further quantitative survey of adults and adolescents with epilepsy and caregivers reveals that the highest priorities for acute seizure medications are fast onset of action (within 1-2 minutes) and non-rectal, user-friendly administration routes.⁸

UCB abstracts during AES 2025:

For further information, contact UCB:

About UCB
UCB, Brussels, Belgium (www.ucb.com) is a global biopharmaceutical company focused on the discovery and development of innovative medicines and solutions to transform the lives of people living with severe diseases of the immune system or of the central nervous system. With approximately 9,000 people in approximately 40 countries, the company generated revenue of €5.3 billion in 2023. UCB is listed on Euronext Brussels (symbol: UCB). Follow us on Twitter: @UCBUSA.

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Indication and Important Safety Information about FINTEPLA^® (fenfluramine) in the US¹

FINTEPLA is indicated for the treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome in patients 2 years of age and older

FINTEPLA is available only through a restricted distribution program called the FINTEPLA REMS. Further information is available at www.FinteplaREMS.com or by telephone at +1 877 964 3649.

IMPORTANT SAFETY INFORMATION

BOXED WARNING: VALVULAR HEART DISEASE and PULMONARY ARTERIAL HYPERTENSION

• FINTEPLA can cause valvular heart disease and pulmonary arterial hypertension.
• Echocardiogram assessments are required before, during, and after treatment with FINTEPLA.
• FINTEPLA is available only through a restricted program called the FINTEPLA REMS.

CONTRAINDICATIONS
Hypersensitivity to fenfluramine or any of the excipients in FINTEPLA. Within 14 days of the administration of monoamine oxidase inhibitors due to an increased risk of serotonin syndrome.

WARNINGS AND PRECAUTIONS
Decreased Appetite and Decreased Weight: Advise patients that FINTEPLA can cause decreased appetite and decreased weight. Somnolence, Sedation, and Lethargy: Monitor for somnolence and sedation. Advise patients not to drive or operate machinery until they have gained sufficient experience on FINTEPLA. Suicidal Behavior and Ideation: Monitor patients for suicidal behavior and thoughts. Withdrawal of Antiepileptic Drugs: FINTEPLA should be gradually withdrawn to minimize the risk of increased seizure frequency and status epilepticus. Serotonin Syndrome: Advise patients that serotonin syndrome is a potentially life-threatening condition and may occur with FINTEPLA, particularly with concomitant administration of FINTEPLA with other serotonergic drugs. Increase in Blood Pressure: Monitor blood pressure during treatment. Glaucoma: Discontinue therapy in patients with acute decrease in visual acuity or ocular pain.

ADVERSE REACTIONS
The most common adverse reactions (incidence at least 10% and greater than placebo) in patients with Dravet Syndrome were decreased appetite; somnolence, sedation, lethargy; diarrhea; constipation; abnormal echocardiogram; fatigue, malaise, asthenia; ataxia, balance disorder, gait disturbance; blood pressure increased; drooling, salivary hypersecretion; pyrexia; upper respiratory tract infection; vomiting; decreased weight; fall; status epilepticus. The most common adverse reactions (incidence at least 10% and greater than placebo) in patients with Lennox-Gastaut syndrome were diarrhea; decreased appetite; fatigue; somnolence; vomiting.

DRUG INTERACTIONS
Strong CYP1A2, CYP2B6, or CYP3A Inducers: Coadministration with strong CYP1A2, CYP2B6, or CYP3A inducers will decrease fenfluramine plasma concentrations. If coadministration of a strong CYP1A2, CYP2B6, or CYP3A inducer with FINTEPLA is necessary, monitor the patient for reduced efficacy and consider increasing the dosage of FINTEPLA as needed. If a strong CYP1A2, CYP2B6, or CYP3A inducer is discontinued during maintenance treatment with FINTEPLA, consider gradual reduction in the FINTEPLA dosage to the dose administered prior to initiating the inducer.

Strong CYP1A2 or CYP2D6 Inhibitors: Coadministration with strong CYP1A2 or CYP2D6 inhibitors will increase fenfluramine plasma concentrations. If FINTEPLA is coadministered with strong CYP1A2 or CYP2D6 inhibitors, the maximum daily dosage of FINTEPLA is 20 mg. If a strong CYP1A2 or CYP2D6 inhibitor is discontinued during maintenance treatment with FINTEPLA, consider gradual increase in the FINTEPLA dosage to the dose recommended without CYP1A2 or CYP2D6 inhibitors. If FINTEPLA is coadministered with stiripentol and a strong CYP1A2 or CYP2D6 inhibitor, the maximum daily dosage of FINTEPLA is 17 mg.

Coadministration of FINTEPLA with stiripentol plus clobazam, with or without valproate, increases fenfluramine plasma concentrations. If FINTEPLA is coadministered with stiripentol plus clobazam, the maximum daily dosage of FINTEPLA is 0.2 mg/kg twice daily (maximum daily dosage of 17 mg).

USE IN SPECIFIC POPULATIONS
There are no data on FINTEPLA use in pregnant women. Available data from epidemiologic studies with fenfluramine or dexfenfluramine are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. FINTEPLA can cause decreased appetite and decreased weight, monitor for adequate weight gain during pregnancy. In animal studies, administration of fenfluramine throughout organogenesis (rat and rabbit) or throughout gestation and lactation (rat) resulted in adverse effects on development (fetal malformations, embryofetal and offspring mortality and growth impairment) in the presence of maternal toxicity at clinically relevant maternal plasma levels of fenfluramine and its major active metabolite. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Please see full Prescribing Information, including Boxed Warning and Medication Guide, for additional Important Safety Information on FINTEPLA.

Indication and Important Safety Information about BRIVIACT^® (brivaracetam) in the US²³
BRIVIACT^® (brivaracetam) CV is indicated for the treatment of partial-onset seizures in patients 1 month of age and older.

IMPORTANT SAFETY INFORMATION

BRIVIACT is associated with important warnings and precautions including suicidal behavior and ideation, somnolence, fatigue, dizziness, disturbance in gait and coordination, psychiatric adverse reactions including nonpsychotic and psychotic symptoms, hypersensitivity reactions (bronchospasm and angioedema), and serious dermatologic reactions. BRIVIACT is contraindicated in patients with a prior hypersensitivity reaction to brivaracetam or any of the inactive ingredients.

In adult adjunctive therapy placebo-controlled clinical trials, the most common adverse reactions (at least 5% for BRIVIACT and at least 2% more frequently than placebo) were somnolence and sedation, dizziness, fatigue, and nausea and vomiting symptoms. Adverse reactions reported in clinical studies of pediatric patients were generally similar to those in adult patients. Adverse reactions with BRIVIACT injection in adult and pediatric patients were generally similar to those observed with BRIVIACT tablets. Other adverse events that occurred in adult patients who received BRIVIACT injection included dysgeusia, euphoric mood, feeling drunk, and infusion site pain.

BRIVIACT is a Schedule V controlled substance.

Please refer to the full Prescribing Information.

Indication and Important Safety Information about VIMPAT^® (lacosamide) in the US²⁴

VIMPAT is indicated for the treatment of partial-onset seizures in patients 1 month of age and older. VIMPAT is indicated as adjunctive therapy in the treatment of primary generalized tonic-clonic seizures in patients 4 years of age and older.

IMPORTANT SAFETY INFORMATION

VIMPAT is associated with important warnings and precautions including suicidal behavior and ideation, dizziness and ataxia, cardiac rhythm and conduction abnormalities, syncope, and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as multi-organ hypersensitivity.

Partial-Onset Seizures

In the adult adjunctive placebo-controlled trials for partial-onset seizures, the most common adverse reactions (≥10% and greater than placebo) were dizziness, headache, nausea, and diplopia. In the adult monotherapy clinical trial, adverse reactions were generally similar to those observed and attributed to drug in adjunctive placebo-controlled trials, with the exception of insomnia (observed at a higher rate of ≥2%). Pediatric adverse reactions were similar to those seen in adult patients.

Primary Generalized Tonic-Clonic Seizures

In the adjunctive therapy placebo-controlled trial for primary generalized tonic-clonic seizures, the adverse reactions were generally similar to those that occurred in the partial-onset seizures trials. The adverse reactions most commonly reported were dizziness, somnolence, headache, and nausea.

VIMPAT contains lacosamide, a Schedule V controlled substance.

Please refer to the full Prescribing Information.

Indication and Important Safety Information about NAYZILAM^® (midazolam) in the US²⁵

NAYZILAM is indicated for the acute treatment of intermittent, stereotypic episodes of frequent seizure activity (i.e., seizure clusters, acute repetitive seizures) that are distinct from a patient's usual seizure pattern in patients with epilepsy 12 years of age and older.

IMPORTANT SAFETY INFORMATION

NAYZILAM is contraindicated in patients with acute narrow-angle glaucoma. Concomitant use of benzodiazepines, including NAYZILAM, and opioids may result in profound sedation, respiratory depression, coma, and death. The use of benzodiazepines, including NAYZILAM, exposes users to risks of abuse, misuse, and addiction, which can lead to overdose or death. The continued use of benzodiazepines may lead to clinically significant physical dependence. Although NAYZILAM is indicated only for intermittent use, if used more frequently than recommended abrupt discontinuation or rapid dosage reduction of NAYZILAM may precipitate acute withdrawal reactions, which can be life-threatening. NAYZILAM may cause an increased CNS-depressant effect when used with alcohol or other CNS depressants. Concomitant use with moderate or strong CYP3A4 inhibitors may result in prolonged sedation due to a decrease in plasma clearance of midazolam. Antiepileptic drugs, including NAYZILAM, increase the risk of suicidal ideation and behavior. Midazolam is associated with a high incidence of partial or complete impairment of recall for the next several hours. Benzodiazepines, including NAYZILAM, can increase intraocular pressure in patients with glaucoma. NAYZILAM use during pregnancy can result in neonatal sedation and/or neonatal withdrawal.

In the randomized, double-blind, placebo-controlled trial, the most common adverse reactions (≥5% in any NAYZILAM treatment group) were somnolence, headache, nasal discomfort, throat irritation, and rhinorrhea.

NAYZILAM is a Schedule IV controlled substance.

Please see full Prescribing Information.

References:

¹ FINTEPLA (fenfluramine) oral solution: U.S. prescribing information. Smyrna, GA: UCB, Inc.
² Specchio N, et al. Fenfluramine in CDKL5 deficiency disorder: primary efficacy and safety results from a phase 3, randomized, double-blind, placebo-controlled study. AES. 2025. Abstract number: 2.429.
³ Gil-Nagel A, et al. Final Results From a Long-Term Open-Label Extension Study (Up to 4 Years): Tolerability of Fenfluramine and Global Functioning of Pediatric and Adult Patients With Dravet or Lennox-Gastaut Syndromes. AES. 2025. Abstract number: 2.428.
⁴ Bailey L, et al. Impacts of Disruptive Seizures, Sleep, and Behaviors on Activities of Daily Living and Communication in Developmental and Epileptic Encephalopathies: Interim Results of a Caregiver Survey. AES. 2025. Abstract number: 2.318.
⁵ Trinka E, et al. Describing the Population of Patients With Prolonged Seizures: US Subgroup Results From a Global Real-World Point-In-Time Study. AES. 2025. Abstract number: 1.305.
⁶ Kaye D, et al. Bridging the Divide: Enhancing Communication and Care Between People Living With Epilepsy and Their Healthcare Providers. AES. 2025. Abstract number: 2.016.
⁷ Ho K-A, et al. Patient and Caregiver Perceptions of Acute Seizure Medications and the Rapid and Early Seizure Termination (REST) Approach: Qualitative Interviews. AES. 2025. Abstract number: 1.317.
⁸ Laloyaux C, et al. Patient and Caregiver Preferences for Acute Seizure Medications: A Quantitative Survey. AES. 2025. Abstract number: 1.314.
⁹ Strzelczyk A, et al. Healthcare Resource Utilization and Antiseizure Medication Claims in Patients With Lennox-Gastaut Syndrome Receiving Fenfluramine in the United States. AES. 2025. Abstract number: 2.431.
¹⁰ Kerr W, et al. Fenfluramine Persistence in Patients With Lennox-Gastaut Syndrome: a Retrospective Analysis Using US Claims Data. AES. 2025. Abstract number: 1.558.
¹¹ Breuillard D, et al. Association of Fenfluramine Treatment and Everyday Executive Functioning in Adult Patients With Lennox-Gastaut Syndrome. AES. 2025. Abstract number: 2.43.
¹² Donner E, at al. Mortality Rates and Risk Factors Among Patients With Lennox-Gastaut Syndrome (LGS) or Dravet Syndrome (DS). AES. 2025. Abstract number: 1.496.
¹³ Meer N, et al. Streamlining The Process of Caregiving for a Loved One with Dravet or Lennox-Gastaut Syndrome. AES. 2025. Abstract number: 2.089.
¹⁴ Fujimoto A, et al. Tolerability and Efficacy of Adjunctive Brivaracetam in Japanese and Chinese Patients With Focal Seizures: Phase 3, Open-Label Extension Trial. AES. 2025. Abstract number: 3.286.
¹⁵ Leanca M, et al. Long-Term Safety, Tolerability, and Efficacy of Brivaracetam in Patients With Childhood Absence Epilepsy or Juvenile Absence Epilepsy. AES. 2025. Abstract number: 2.334.
¹⁶ Kimiskidis V, et al. Digital Application Usage in Epilepsy: Insights From Real-World Setting Studies BRIVA-Reg and BRITOBA. AES. 2025. Abstract number: 3.14.
¹⁷ McClung C, et al. Long-Term Use of Oral Lacosamide in Young Children With Epilepsy Who Received Lacosamide in Previous Trials: Data From a Multicenter, Open-Label, Follow-Up Trial. AES. 2025. Abstract number: 3.362.
¹⁸ Moseley B, et al. Efficacy, Safety, and Pharmacokinetics of Lacosamide in Neonates With Seizures: Results of a Phase 2/3, Open-Label, Randomized, Active Comparator Trial. AES. 2025. Abstract number: 2.342.
¹⁹ Morris G, et al. Healthcare Resource Utilization and Costs With the Introduction of Intranasal Midazolam in Acute Seizure Management: A Wisconsin-Based Claims Analysis. AES. 2025. Abstract number: 1.514.
²⁰ Wolff C, et al. AAV Mediated Overexpression of STXBP1 Variants in a Mouse Model of STXBP1 Haploinsufficiency. AES. 2025. Abstract number: 3.051.
²¹ Rodriguez N, et al. AAV Gene Therapy in Juvenile Mice of STXBP1 Haploinsufficiency. AES. 2025. Abstract number: 1.048.
²² Rajman M, et al. Reactive Mouse Primary Astrocytes as a Model to Explore Glial Gene Expression Profiles Identified in Human Temporal Lobe Epilepsy. AES. 2025. Abstract number: 3.059.
²³ BRIVIACT (brivaracetam): US prescribing information. Smyrna, GA: UCB, Inc.
²⁴ VIMPAT (lacosamide): US prescribing information. Smyrna, GA: UCB, Inc.
²⁵ NAYZILAM (midazolam): US prescribing information. Smyrna, GA: UCB, Inc.

BRIVIACT^®, FINTEPLA^®, and NAYZILAM^® are registered trademarks of the UCB Group of Companies.
VIMPAT^® is a registered trademark used under license from Harris FRC Corporation.
©2025 UCB, Inc., Smyrna, GA 30080. All rights reserved. US-BR-2500126

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