The interleukin-6 receptor inhibitor gains a second indication, though one of two phase 3 trials missed its primary endpoint.
The FDA approved Enspryng (satralizumab) on Oct. 16 for adults with thyroid eye disease (TED).1 Roche describes the interleukin-6 receptor inhibitor as the first subcutaneous therapy for the condition, which patients or caregivers can administer at home after training from a health care provider.1
The decision follows a priority review and adds a second indication for the drug, which was approved in 2020 for neuromyelitis optica spectrum disorder.1 It also places a self-administered option alongside infusion-based therapies, although the pivotal evidence is mixed: one of two phase 3 trials missed its primary endpoint.1
“Today’s FDA approval of Enspryng provides an important new option for people with thyroid eye disease, who have long faced limited treatment choices,” said Levi Garraway, MD, PhD, Roche’s Chief Medical Officer and Head of Global Product Development. “As the first subcutaneous treatment for this condition, Enspryng offers a positive safety and efficacy profile and the potential for at-home administration.”
The approval rests on SatraGO-1 and SatraGO-2, identically designed phase 3 trials that randomized 258 adults from 19 countries 1:1 to Enspryng or placebo.1 Enrollment included patients with active, moderate-to-severe disease and those with chronic disease, and the studies ran 72 weeks.2
The primary endpoint was the share of patients with active, moderate-to-severe disease who achieved a reduction of at least 2 mm in proptosis, or eye bulging, in the study eye at week 24.1 Results diverged between the trials.
In SatraGO-1, the proptosis response was 49% with Enspryng versus 31.2% with placebo, which did not reach statistical significance; researchers attributed the gap to an unexpectedly high placebo response.3 In SatraGO-2, 52.9% of patients with active disease on Enspryng had a proptosis response versus 23.4% on placebo, and 60.7% had reduced diplopia, or double vision, versus 25.8%.1
Roche reports consistent results in the overall SatraGO-2 population and no new safety signals, with a safety profile in line with the drug’s record in neuromyelitis optica spectrum disorder.1
TED, also known as Graves’ ophthalmopathy, is a progressive autoimmune disease of the eyes and surrounding tissue that can cause proptosis, diplopia, pain and, if untreated, facial disfigurement and vision-threatening complications.1 Roche cites a U.S. prevalence of about 155 per 100,000 people; roughly half of those with hyperthyroidism experience at least mild disease.1
“Thyroid eye disease not only affects a person’s eyes through bulging and vision problems, but it also takes a profound emotional toll on confidence, identity, relationships and daily life,” said Christine Gustafson, CEO of the TED Community Organization. “Until now, our community has had very limited choices. The approval of Enspryng represents a critical turning point through a convenient, targeted option.”
Two disease-specific therapies are already approved, according to trade press: Tepezza (teprotumumab) in 2020 and, more recently, Lumvoa (veligrotug).3 Roche acknowledges that a need remains for therapies that are effective, well tolerated and convenient to administer.1
Enspryng, which inhibits interleukin-6 signaling, is dosed at weeks 0, 2 and 4, then every four weeks.1,3 In the phase 3 trial supporting Tepezza, patients received eight intravenous infusions every three weeks, and 71% met the 2 mm proptosis threshold at week 24 versus 20% with placebo.4
The trials differed in design and populations, so the results are not directly comparable. The case for the subcutaneous route rests on treatment burden rather than demonstrated superiority.
“Treating thyroid eye disease requires balancing efficacy, safety, and the practical realities of long-term treatment,” said César A. Briceño, MD, clinical trial investigator and associate professor of Ophthalmology at the Scheie Eye Institute, University of Pennsylvania. “As a clinical trial investigator, I have seen firsthand the potential of targeted therapies such as Enspryng. The availability of an effective subcutaneous treatment option could provide greater flexibility for both patients and physicians while reducing the logistical burden associated with infusion-based therapies. Enspryng has the potential to meaningfully expand our therapeutic options for patients with thyroid eye disease.”
The evidence has gaps. One of two pivotal trials missed its primary endpoint, no head-to-head comparison with approved therapies was reported, and Roche did not disclose pricing or launch timing.
Long-term outcomes beyond the week 24 primary analysis were not described in the sources reviewed. Next, the FDA granted priority review to a supplemental application for Enspryng in myelin oligodendrocyte glycoprotein antibody-associated disease, with a decision expected in January 2027.1
The drug is also being studied in additional neurological autoimmune and inflammatory conditions.1
Sources
1. FDA approves Roche’s Enspryng, a first-in-class IL-6R inhibitor, as the first and only at-home subcutaneous treatment option for thyroid eye disease (TED). News release. Roche; October 16, 2026. Accessed October 16, 2026. https://www.roche.com/media/releases/med-cor-2026-10-16
2. Ezra D, Collins A, Haskova Z, et al. Targeting IL-6 receptor signaling with satralizumab in thyroid eye disease: design of the phase 3 SatraGO-1 and SatraGO-2 trials. Ophthalmol Ther. 2025;14(12):3119-3132. doi:10.1007/s40123-025-01255-3
3. Satralizumab shows clinically meaningful improvements in TED. Review of Optometry. September 14, 2026. Accessed October 16, 2026. https://www.reviewofoptometry.com/news/article/satralizumab-shows-clinically-meaningful-improvements-in-ted
4. Douglas RS, Kahaly GJ, Patel A, et al. Teprotumumab for the treatment of active thyroid eye disease. N Engl J Med. 2020;382(4):341-352. doi:10.1056/NEJMoa1910434
