Possible Optic Neuritis Treatment Receives Breakthrough Therapy Designation

The Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation to privosegtor (Oculis Holding, Zug, Switzerland) for the treatment of people with optic neuritis based on clinical evidence demonstrating improvement in visual outcomes compared with standard therapy. The designation reflects preliminary clinical data suggesting that privosegtor treatment may provide a substantial improvement over available treatments for this sight-threatening neuro-ophthalmic condition that often manifests early in people with multiple sclerosis (MS).

The designation was supported by results from the phase 2 ACUITY clinical trial (NCT04762017) in individuals with acute optic neuritis. In this study, participants were randomized to receive treatment with either privosegtor at 2 mg/kg/d or 3 mg/kg/d or placebo administered in combination with intravenous (IV) methylprednisone. Visual function was assessed using the 2.5% Early Treatment Diabetic Retinopathy Study low-contrast visual acuity (LCVA) chart. Safety assessments included monitoring for adverse events and serious adverse events. In addition to functional measures, anatomical and biomarker-based outcomes were evaluated.

Key findings from the ACUITY trial include the following:

• Patients treated with privosegtor 3 mg/kg/day + IV methylprednisolone gained an average of 18 letters on the 2.5% LCVA chart at 3 months compared with placebo + IV methylprednisolone.
• Privosegtor treatment was associated with preservation of retinal and optic nerve structure during acute optic neuritis.
• Treatment with privosegtor was associated with reduced neurofilament release, a biomarker linked to neuroaxonal injury.
• The most common drug-related adverse events were headache and acne, each reported in 10.5% of participants.
• No drug-related serious adverse events or treatment discontinuations were reported.

Privosegtor is currently being evaluated in the registrational PIONEER program, which includes multiple pivotal trials in optic neuritis and nonarteritic anterior ischemic optic neuropathy.

“The ACUITY trial delivered truly groundbreaking results, demonstrating for the first time in a single study that a drug candidate consistently improves visual function alongside anatomical and biological evidence of neuroprotective benefit,” said Mark Kupersmith, MD, Chief Medical Advisor of Neuro-Opthalmology at Oculis Holdings. “Significant unmet medical needs remain, as patients with optic neuritis—more often young women and frequently experiencing the first sign of multiple sclerosis—are still at high risk of permanent visual loss.”

Source: Oculis Holding AG. Oculis announces U.S. FDA breakthrough therapy designation granted to privosegtor for treatment of optic neuritis. Oculis. Published January 6, 2025. Accessed January 8, 2026. https://investors.oculis.com/news-releases/news-release-details/oculis-announces-us-fda-breakthrough-therapy-designation-granted