BOSTON, Aug. 3, 2026
Zevra Therapeutics, Inc. announced the publication of four-year real-world safety and effectiveness data evaluating MIPLYFFA® (arimoclomol) in patients with Niemann-Pick disease type C (NPC), providing new evidence from the U.S. Early Access Program (EAP). Published in Molecular Genetics and Metabolism, the longitudinal study includes the first published real-world data in adults with NPC, a population that has historically been underrepresented in clinical research. The analysis followed patients treated during routine clinical practice for up to four years, offering important long-term insights into disease progression, treatment outcomes, and safety across a broad range of ages and disease severities. The findings further strengthen the evidence supporting MIPLYFFA, which received U.S. Food and Drug Administration (FDA) approval in September 2024 for the treatment of neurological manifestations of NPC when used in combination with miglustat.
Four-Year Real-World Study Demonstrates Consistent Long-Term Outcomes
The U.S. Early Access Program enrolled 109 patients across 14 clinical sites, including 53 adults, representing nearly half of the study population. Approximately 65% of participants received concomitant miglustat therapy, while the mean exposure to arimoclomol reached 820 days. Researchers assessed disease progression using the 5-domain NPC Clinical Severity Scale (5DNPCCSS) during routine clinical care. Across follow-up periods extending through Years 1, 2, 3, and 4, mean disease severity scores remained relatively stable, indicating sustained long-term clinical outcomes. Additional analyses using the rescored 4-domain NPC Clinical Severity Scale (R4DNPCCSS) demonstrated comparable findings, reinforcing the consistency of the treatment effect observed throughout the study period.
Safety Findings Support Established Profile of MIPLYFFA
The publication reported that the long-term safety profile observed during the Early Access Program remained consistent with previously established clinical data for MIPLYFFA (arimoclomol). No new safety concerns were identified beyond the known adverse events described in earlier clinical studies. MIPLYFFA, approved by the FDA in September 2024, works by increasing activation of transcription factors EB (TFEB) and E3 (TFE3), promoting lysosomal function through upregulation of CLEAR genes. In its pivotal Phase 3 clinical trial, the therapy demonstrated the ability to halt disease progression compared with placebo over one year using the validated NPC Clinical Severity Scale. The product has also received Orphan Medicinal Product designation from the European Medicines Agency (EMA), and the company has submitted a Marketing Authorization Application (MAA) seeking approval in Europe.
Advertisement
Publication Reinforces Zevra’s Leadership in Rare Disease Treatment
The newly published real-world evidence expands the growing body of clinical experience supporting MIPLYFFA, with more than 270 patients worldwide evaluated across Phase 2/3 studies, open-label extension trials, expanded access programs, and pediatric investigations, representing the largest clinical development program ever conducted in NPC. By providing long-term data from routine clinical practice, including the first published outcomes in adult NPC patients, the study offers valuable information for clinicians managing this ultra-rare neurodegenerative disease. As Zevra Therapeutics continues expanding global access to MIPLYFFA while advancing its broader rare disease pipeline, these findings further support the therapy’s role as an important treatment option for patients living with Niemann-Pick disease type C.
Source: Zevra Therapeutics press release
