CARLSBAD, Calif., June 25, 2026
Ionis Pharmaceuticals has entered into a landmark global licensing agreement with Recordati to accelerate the development and commercialization of zilganersen, an investigational RNA-targeted therapy for Alexander disease (AxD), a rare, progressive and often fatal neurological disorder. Under the agreement, Recordati receives exclusive rights to develop and commercialize zilganersen in all countries outside the United States, while Ionis retains full commercial rights in the U.S. and will continue to lead the medicine’s global clinical development. The strategic partnership combines Ionis’ leadership in RNA-targeted therapeutics with Recordati’s extensive rare disease commercialization expertise, creating a pathway to expand patient access worldwide should the therapy receive regulatory approvals. The collaboration also reinforces the growing momentum in rare disease innovation, where specialized partnerships are increasingly helping accelerate global availability of transformative medicines.
Strategic Global Partnership to Accelerate Rare Disease Access
The licensing agreement positions both companies to maximize the worldwide potential of zilganersen, an investigational antisense oligonucleotide (ASO) designed to reduce production of glial fibrillary acidic protein (GFAP), the disease-causing protein responsible for Alexander disease. Under the terms of the agreement, Ionis will receive an upfront payment of $30 million, with the opportunity to earn additional milestone payments and tiered royalties reaching the mid-20% range on annual net sales.
While Ionis will independently commercialize the therapy in the United States, Recordati will oversee regulatory submissions, commercialization activities, and country-specific early access programs outside the U.S., leveraging its established global rare disease infrastructure. Company executives emphasized that the collaboration is intended to rapidly bring a potentially transformative therapy to patients suffering from a devastating neurological disorder that currently has no approved disease-modifying treatment.
Positive Clinical Results Strengthen Regulatory Outlook
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The partnership follows encouraging results from the pivotal clinical study evaluating zilganersen in patients with Alexander disease. The investigational therapy achieved its primary endpoint, demonstrating statistically significant and clinically meaningful stabilization of gait speed using the 10-Meter Walk Test (10MWT) at Week 61 in patients aged five years and older. Secondary and exploratory outcome measures, including patient-reported, caregiver-reported, and clinician-assessed evaluations, consistently favored zilganersen, highlighting improvements across multiple disease symptoms and functional outcomes.
Importantly, the therapy also demonstrated a favorable safety and tolerability profile, with most adverse events reported as mild to moderate, while serious treatment-emergent adverse events occurred less frequently than in the control group. These findings further strengthen confidence in the therapy as a potential breakthrough treatment for patients with this devastating neurodegenerative condition.
Potential First Disease-Modifying Therapy for Alexander Disease
Alexander disease (AxD) affects approximately one to three individuals per million worldwide and is caused by mutations in the GFAP gene, leading to progressive neurological decline, loss of mobility, swallowing difficulties, respiratory complications, and premature death. Currently, patients have no approved disease-modifying therapies, making zilganersen a potentially transformative medical advancement. The therapy has already received FDA Breakthrough Therapy, Orphan Drug, and Rare Pediatric Disease designations, while the European Medicines Agency (EMA) has also granted Orphan Drug designation, recognizing its potential to address a significant unmet medical need.
The medicine is currently under U.S. FDA review, with a Prescription Drug User Fee Act (PDUFA) action date of September 22, 2026. If approved, zilganersen would become the first disease-modifying treatment for Alexander disease and also represent Ionis’ first independently commercialized neurology product, marking an important milestone in the company’s long-term strategy to expand its leadership in RNA-targeted neurological therapeutics while delivering innovative treatment options to patients living with rare neurological diseases worldwide.
Source: Ionis Pharmaceuticals, Recordati press release
