FDA Approvals Highlight Rare Neurologic Therapies as Purple Day Raises Awareness for Epilepsy

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Welcome to the Neurology News Network. My name is Louie Pasculli. Here’s a look at this week’s top stories in neurology.

Welcome to the Neurology News Network. My name is Louie Pasculli. Here’s a look at this week’s top stories in neurology.

Beginning with FDA news, the FDA has granted accelerated approval to tividenofusp alfa (Denali Therapeutics) for the treatment of neurologic manifestations of Hunter syndrome, also known as mucopolysaccharidosis type II (MPS II), in pediatric patients. Marketed as Avlayah, it becomes the first therapy specifically engineered to cross the blood-brain barrier in this rare lysosomal storage disorder.¹

Ryan Watts, PhD, co-founder and chief executive officer at Denali, said this in a statement “The approval of AVLAYAH is a new era for the Hunter syndrome community as we deliver the first FDA-approved therapy designed to cross the brain’s protective barrier for individuals and families living with this debilitating disease. This approval reflects the determination and partnership of the MPS community, as well as the FDA’s collaborative engagement to incorporate biomarker evidence to help accelerate the development of urgently needed treatments.”¹

The FDA’s accelerated approval of tividenofusp alfa was supported by data from an ongoing phase 1/2, open-label study of 47 patients with Hunter syndrome, with findings that have matured over time. Previously reported data demonstrated substantial reductions in both central nervous system and peripheral disease biomarkers.

Sticking with FDA news, according to a new company update, the FDA has accepted for priority review Ionis Pharmaceuticals’ new drug application (NDA) for its investigational RNA-targeted therapy zilganersen as a potential treatment of patients with Alexander disease (AxD), a rare neurologic disorder. The agency has assigned a prescription drug user fee act (PDUFA) target action date of September 22, 2026.²

“We are pleased the FDA has granted Priority Review for zilganersen. This decision recognizes the urgent need for treatment options and brings us one step closer to offering patients, who currently have no disease-modifying therapies, a potential treatment as quickly as possible,” an Ionis spokesperson told NeurologyLive®. “If approved, zilganersen will be the first and only treatment for Alexander disease, marking a breakthrough for patients who are living with this rare, often fatal neurological condition.”

In recognition of Purple Day®, held March 26, 2026, it is important to acknowledge that women with epilepsy may face distinct, often underrecognized risks across the lifespan. These include potential interactions between antiseizure medications (ASMs) and hormonal contraception that may reduce contraceptive efficacy, as well as the need for careful treatment planning during pregnancy because of possible fetal risks.³ In addition, hormonal fluctuations during puberty, the reproductive years, and perimenopause may contribute to variability in seizure patterns, sometimes complicating disease management.⁴

To further contextualize these considerations, adult epileptologist Danielle Becker, MD, MS, FAES, the division director of epilepsy and associate professor of neurology at The Ohio State University Wexner Medical Center, spoke with NeurologyLive® about the broader challenges and opportunities in optimizing care for women with epilepsy. She highlighted ongoing gaps in awareness and implementation of sex-specific considerations, pointing to emerging efforts from organizations to better integrate these factors into clinical practice. She also touched on evolving approaches to care across the lifespan and the importance of multidisciplinary strategies to help clinicians address these complexities in a more structured and proactive way.

To read the full interview and to get more direct access to expert insight, head to NeurologyLive.com. Be sure to tune in next week to stay up to date on the latest in neurology. I’m Louie Pasculli, thanks for watching Neurology News Network.

REFERENCES
1. Denali Therapeutics Announces U.S. FDA Approval of AVLAYAH™ (tividenofusp alfa-eknm) for Treatment of Hunter Syndrome (MPS II). News release. Denali Therapeutics. March 25, 2026. Accessed March 25, 2026. https://investors.denalitherapeutics.com/news-releases/news-release-details/denali-therapeutics-announces-us-fda-approval-avlayahtm
2. Ionis announces zilganersen New Drug Application for Alexander disease (AxD) accepted by FDA for Priority Review. News release. Ionis Pharmaceuticals. March 23, 2026. Accessed March 23, 2026. https://ir.ionis.com/news-releases/news-release-details/ionis-announces-zilganersen-new-drug-application-alexander
3. Li Q, Zhang Z, Fang J. Hormonal Changes in Women with Epilepsy. Neuropsychiatr Dis Treat. 2024;20:373-388. Published 2024 Feb 26. doi:10.2147/NDT.S453532
4. Nucera B, Rinaldi F, Dono F, et al. Progesterone and its derivatives for the treatment of catamenial epilepsy: A systematic review. Seizure. 2023;109:52-59. doi:10.1016/j.seizure.2023.05.004