FDA Action Update, May 2026: Approvals, Priority Review, and Extension of Review

The FDA was busy in May 2026, making a number of decisions on potential new therapeutic agents, including accepting a resubmission, granting a clearance, and issuing a complete response letter.

With all the treatments that have progressed through the pipeline of clinical development, the NeurologyLive^® team has been hard at work covering all the agency movements to make sure you are up to date on the latest news in neurology. To give you a chance to catch up on any of the headlines you may have missed, we’ve compiled all the updates here. The coverage includes the latest FDA approvals, new designations, submissions, resubmissions, and clinical trial initiations and holds.

FDA Extends Review of Subcutaneous Starting Dose for Lecanemab in Early Alzheimer Disease

At the beginning of the month, on May 8, 2026, the FDA extended its review of Eisai and Biogen’s supplemental biologics license application (sBLA) for a once-weekly subcutaneous autoinjector starting regimen of lecanemab-irmb (Leqembi Iqlik) in early Alzheimer disease (AD), pushing the Prescription Drug User Fee Act (PDUFA) action date to August 24, 2026.¹

According to the companies, the FDA requested additional information during its ongoing review and classified the submission as a “major amendment,” resulting in a standard 3-month extension to allow time for full evaluation of the updated materials. Importantly, Eisai and Biogen noted that the agency “has not raised any concerns to date regarding the approvability” of the subcutaneous starting-dose regimen.

If approved, the expanded indication would allow patients with mild cognitive impairment (MCI) or mild dementia because of AD to initiate treatment directly with a once-weekly subcutaneous autoinjector formulation rather than first receiving biweekly intravenous infusions. The proposed regimen builds on the FDA’s August 2025 approval of Leqembi Iqlik for maintenance dosing, which became the first at-home, self-administered antiamyloid treatment option for AD.

FDA Approves Ocrelizumab for Pediatric Patients With Relapsing-Remitting Multiple Sclerosis

On the same day, on May 8, 2026, the FDA approved intravenous ocrelizumab (Ocrevus; Genentech) for the treatment of relapsing-remitting multiple sclerosis (RRMS) in pediatric patients aged 10 years and older who weigh at least 55 pounds, expanding a high-efficacy anti-CD20 therapy into a younger population with often highly active disease.²

With the decision, ocrelizumab becomes an FDA-approved treatment option for pediatric RRMS, a group that accounts for an estimated 3% to 5% of MS cases globally and approximately 5000 to 10,000 children and adolescents in the United States. The approval was supported by data from the phase 3 OPERETTA 2 study (NCT05123703), which compared ocrelizumab with fingolimod (Gilenya; Novartis), previously the only FDA-approved therapy for pediatric RRMS.

“This approval represents a landmark for children living with MS in the US and their families, which can help close the longstanding gap in high-efficacy treatment options for children aged 10 and older,” Levi Garraway, MD, PhD, chief medical officer and head of Global Product Development at Genentech, said in a statement.² “By bringing a decade of efficacy and safety data to this younger population, Ocrevus may reduce relapses and potentially redefine what’s possible for their future.”

Efgartigimod Gains FDA Approval as First Treatment for Seronegative Forms of Myasthenia Gravis

On the same day, on May 8, 2026, FDA has approved the expanded indication of efgartigimod alfa-fcab (Vyvgart; argenx) to include adults with acetylcholine receptor antibody (AChR-Ab) seronegative generalized myasthenia gravis (gMG) who do not have detectable anti-acetylcholine receptor antibodies (AChR-Ab). The approval extends the anti–FcRn therapy beyond its prior use in AChR-Ab–positive patients becoming the first approved treatment for the newly included seronegative population, marking a broader biomarker-independent use of the FcRn inhibitor in gMG.³

Efgartigimod’s approval stemmed largely from the results of phase 3 ADAPT SERON study (NCT06298552), a randomized, double-blind, placebo-controlled trial that featured 119 patients followed over a 5-week treatment period. The study is the largest study to date of patients with gMG who do not have detectable AChR-Ab across 3 serotypes. In the study, patients were randomly assigned to receive 4 once-weekly intravenous infusions of efgartigimod or placebo, with change in Myasthenia Gravis Activities of Daily Living as the primary end point, recorded at 29 days.

“Today’s approval means that all adult gMG patients, regardless of serotype, can now benefit from VYVGART’s rapid onset, sustained disease control, and favorable safety profile,” Luc Truyen, MD, PhD, chief medical officer at argenx, said in a statement.³ "For clinicians, this simplifies treatment decisions, representing a major advancement in reaching as many patients living with gMG as possible.”

FDA Grants Priority Review to Bayer’s Asundexian for Secondary Stroke Prevention

About a week later, on May 19, 2026, the FDA accepted Bayer’s new drug application (NDA) for asundexian, an investigational oral factor XIa (FXIa) inhibitor, and granted the therapy priority review for the prevention of recurrent stroke in patients following a non-cardioembolic ischemic stroke or transient ischemic attack (TIA). The regulatory submission was supported by positive findings from the pivotal phase 3 OCEANIC-STROKE trial, which demonstrated significant reductions in ischemic stroke risk without increasing major bleeding.⁴

If approved, asundexian could become the first FXIa inhibitor indicated for secondary stroke prevention, representing a potentially important advance in antithrombotic therapy for a population that continues to face high rates of recurrent vascular events despite current standards of care.

“Secondary stroke remains a serious and persistent challenge, and the FDA’s Priority Review designation underscores the urgency of advancing potential new approaches in secondary stroke prevention,” Yesmean Wahdan, MD, senior vice president of U.S. Medical Affairs at Bayer, said in a statement.⁴ “We are proud of this important milestone that builds on our long-standing commitment to innovation in anti-thrombotic therapies and look forward to collaborating with the FDA as we work to bring asundexian to patients in need.”

FDA Grants Priority Review to Levacetylleucine for Ataxia-Telangiectasia, Potentially Positioning First Approved Therapy

A couple of days later, on May 20, 2026, FDA accepted a IntraBio’s supplemental new drug application (sNDA) for levacetylleucine (AQNEURSA) for the treatment of ataxia-telangiectasia (A-T) in adult and pediatric patients. The administration has also granted the application Priority Review, assigning a Prescription Drug User Fee Act (PDUFA) target action date of September 19, 2026.⁵

If approved, levacetylleucine would become the first FDA-approved therapy specifically indicated for A-T, a rare inherited neurodegenerative condition characterized by progressive cerebellar dysfunction, immunodeficiency, and increased malignancy risk.

“Today’s announcement represents a step forward — not just for IntraBio, but for the thousands of patients and families living with Ataxia-Telangiectasia who have waited far too long for a treatment option,” Mallory Factor, president and chief executive officer at IntraBio in Austin Texas, said in a statement.⁵ “The FDA’s Priority Review designation reflects the urgency of this unmet need, and we are fully committed to working with the agency to make AQNEURSA the first approved therapy for A-T as swiftly as possible.”

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REFERENCES
1. Update on FDA Priority Review of LEQEMBI® IQLIK™ (lecanemab-irmb) Subcutaneous Injection as a Starting Dose for Early Alzheimer’s Disease. News release. Eisai and Biogen. May 8, 2026. Accessed May 8, 2026. https://investors.biogen.com/news-releases/news-release-details/update-fda-priority-review-leqembir-iqliktm-lecanemab-irmb
2. FDA approves Ocrevus (ocrelizumab) for pediatric relapsing multiple sclerosis. News release. Genentech. Published May 2026. Accessed May 2026. https://www.gene.com/media/statements/ps_050826
3. Argenx Announces U.S. FDA Approval Expanding VYVGART and VYVGART Hytrulo for Use in All Adult Patients Living with gMG. Argenx. News Release. May 8, 2026. Accessed: May 8, 2026. https://argenx.com/news/2026/press-release-3291372
4. Bayer Granted Priority Review by U.S. FDA for Asundexian in Patients After a Non-Cardioembolic Ischemic Stroke or Transient Ischemic Attack. News release. Bayer. May 18, 2026. Accessed May 19, 2026. https://www.businesswire.com/news/home/20260518787299/en/Bayer-Granted-Priority-Review-by-U.S.-FDA-for-Asundexian-in-Patients-After-a-Non-Cardioembolic-Ischemic-Stroke-or-Transient-Ischemic-Attack
5. FDA accepts sNDA and grants Priority Review to AQNEURSA for Ataxia-Telangiectasia. News release. IntraBio Inc. Published May 2026. Accessed May 20, 2026. https://www.businesswire.com/news/home/20260519802425/en/FDA-Accepts-sNDA-and-Grants-Priority-Review-to-AQNEURSA-for-Ataxia-Telangiectasia