SOUTH SAN FRANCISCO, Calif., June 29, 2026
Genentech, a member of the Roche Group, announced that the U.S. Food and Drug Administration (FDA) has accepted and granted Priority Review to its supplemental Biologics License Application (sBLA) for Enspryng® (satralizumab) as a treatment for thyroid eye disease (TED). The application is supported by data from the global Phase III SatraGO-1 and SatraGO-2 clinical trials, which demonstrated clinically meaningful improvements in proptosis (bulging eyes), diplopia (double vision), and disease activity in patients with moderate-to-severe TED. The FDA has assigned a PDUFA target action date of October 15, 2026. If approved, Enspryng would become the first and only at-home subcutaneous disease-modifying treatment for thyroid eye disease, offering patients a convenient alternative to hospital-based intravenous therapies.
Phase III Studies Demonstrated Significant Clinical Benefits
The pivotal SatraGO-1 and SatraGO-2 studies enrolled 258 patients across 19 countries and evaluated the safety and efficacy of Enspryng versus placebo in active, moderate-to-severe thyroid eye disease. In SatraGO-2, 53% of patients receiving Enspryng achieved the primary endpoint of at least a 2 mm reduction in proptosis at Week 24 compared with 23% receiving placebo, reaching statistical significance. In SatraGO-1, 49% of treated patients achieved the same response compared with 31% in the placebo group, providing supportive evidence for the therapy. Across both trials, 78% to 90% of patients experienced reductions in Clinical Activity Score (CAS), while 44% to 61% achieved meaningful improvements in diplopia, demonstrating consistent benefits across multiple clinically important disease measures. No new safety concerns were identified, and the therapy maintained a safety profile consistent with its approved use in neuromyelitis optica spectrum disorder (NMOSD).
Potential First At-Home Disease-Modifying Therapy for TED
Enspryng (satralizumab) is a humanized monoclonal antibody targeting the interleukin-6 (IL-6) receptor, designed using Roche’s proprietary recycling antibody technology that enables prolonged inhibition of inflammatory signaling. The therapy is already approved in approximately 90 countries for the treatment of NMOSD, with safety experience in more than 10,000 patients worldwide. If approved for TED, Enspryng would become the first disease-modifying therapy administered through subcutaneous injections at home, potentially reducing treatment burden while improving patient convenience. Thyroid eye disease affects approximately 155 people per 100,000 population and can lead to severe eye inflammation, facial disfigurement, vision impairment, and permanent visual complications if left untreated.
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FDA Decision Expected in October 2026
The FDA’s decision to grant Priority Review highlights the significant unmet medical need for additional treatment options in thyroid eye disease. According to Genentech, the company believes Enspryng’s novel IL-6 inhibition mechanism, combined with strong efficacy data and favorable safety results, could establish a new treatment approach for patients living with TED. Alongside its ophthalmology pipeline, Genentech continues expanding development of Enspryng across additional autoimmune neurological disorders, including MOGAD and autoimmune encephalitis. A final FDA approval decision is expected by October 15, 2026, potentially introducing the first at-home biologic therapy designed to modify the underlying disease process in thyroid eye disease.
Source: Genentech, press release
