FDA Grants Priority Review to Roche's Enspryng as First At-Home Subcutaneous Therapy for Thyroid Eye Disease
核心洞察
The FDA has accepted and granted priority review to Roche's supplemental Biologics License Application for Enspryng (satralizumab) (搜索) for the treatment of thyroid eye disease (搜索), with a decision expected by 15 October 2026.
In the pivotal phase III SatraGO-2 trial, 53% of patients treated with Enspryng achieved a proptosis reduction at week 24 compared to 23% on placebo, meeting statistical significance.
Enspryng, a humanised monoclonal antibody targeting the IL-6 receptor (搜索), could become the first at-home subcutaneous disease-modifying standard of care for TED, a progressive autoimmune disease affecting approximately 155 per 100,000 people.
The US Food and Drug Administration has accepted and granted priority review to a supplemental Biologics License Application (sBLA) for Roche's Enspryng (satralizumab) (搜索) for the treatment of thyroid eye disease (搜索) (TED), the company announced on 30 June 2026. The FDA is expected to make a decision on approval by 15 October 2026.
"The FDA's decision to grant priority review to Enspryng is an important step toward expanding treatment options for people living with thyroid eye disease (搜索)," said Levi Garraway, MD, PhD, Roche's Chief Medical Officer and Head of Global Product Development. "By targeting the underlying disease biology with a novel mechanism of action, this subcutaneous therapy has the potential to introduce a new treatment approach that combines clinical efficacy and a favourable safety profile with the convenience of at-home administration."
Phase III SatraGO Programme Results
The filing acceptance is based on results from two identically designed, randomised, placebo-controlled global phase III studies — SatraGO-1 (NCT05987423) and SatraGO-2 (NCT06106828) — which assessed the safety and efficacy of Enspryng in adults with active, moderate-to-severe TED and chronic inactive TED. The studies enrolled a total of 258 patients from 19 countries, with participants randomised 1:1 to receive Enspryng or placebo. The data were presented at the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) Fall Scientific Symposium in October 2025.
For the primary endpoint of proptosis response at week 24 — defined as an at least 2 mm reduction in proptosis in the study eye from baseline — 53% of patients treated with Enspryng in SatraGO-2 achieved a response compared to 23% of patients in the placebo arm, meeting statistical significance. In the SatraGO-1 trial, 49% of patients achieved a proptosis response compared to 31% in the placebo arm. While this numerical improvement did not meet statistical significance, SatraGO-1 offers additional confirmatory evidence regarding the potential benefit of satralizumab in this setting.
Beyond proptosis, Enspryng drove notable improvements across secondary measures in both studies. Reductions in clinical activity score (CAS) were achieved for 78% to 90% of patients with active TED, and improvements in double vision (diplopia) were observed in 44% to 61% of patients with active TED in SatraGO-1 and SatraGO-2, respectively.
No new safety signals were identified in the SatraGO trials, with Enspryng's safety profile remaining consistent with its known profile in neuromyelitis optica spectrum disorder (搜索) (NMOSD), where it has a well-established safety record in over 10,000 patients.
Mechanism of Action and Development History
Enspryng, developed by Chugai, a member of the Roche Group, is a humanised monoclonal antibody that targets IL-6 receptor (搜索) activity. The drug was designed using novel recycling antibody technology which, compared to conventional technology, allows for sustained IL-6 inhibition by binding strongly and repeatedly to the IL-6 receptor, enabling rapid and sustained suppression of inflammatory pathways.
Enspryng is currently the first and only IL-6 inhibitor approved in approximately 90 countries for NMOSD, including in the European Union and United States. Roche is also developing Enspryng in additional neurological autoimmune and inflammatory diseases, including autoimmune encephalitis and myelin oligodendrocyte glycoprotein antibody-associated disease (搜索) (MOGAD). The company recently announced positive phase III results for Enspryng in MOGAD, with regulatory submissions planned this year.
Thyroid Eye Disease (搜索): Unmet Medical Need
TED, also known as Graves' ophthalmopathy, is a complex inflammatory autoimmune disease affecting the area around the eyes that can be sight-threatening, debilitating, and disfiguring. The most common symptoms include redness, swelling of the eyes, eyelid retraction, appearance of a stare, bulging of one or both eyes (proptosis), double vision (diplopia), and pain.
TED is a progressive rare disease affecting approximately 155 out of every 100,000 people. It most commonly occurs in people with hyperthyroidism — approximately 50% of whom experience at least mild TED — but can also affect people with hypothyroidism or normal thyroid function. Despite existing approved treatments for TED, a medical need remains for therapies that are effective, well-tolerated, and have a convenient route of administration.
If approved, Enspryng would become the first at-home subcutaneous disease-modifying standard of care for TED, potentially addressing this unmet need by combining clinical efficacy with the convenience of self-administration.