Key Takeaways

  • The FDA approved Enspryng as the first at-home subcutaneous treatment for adults with thyroid eye disease

  • The approval follows a priority review and is supported by results from the phase 3 SatraGO clinical program, which demonstrated improvements in proptosis and diplopia

  • No new safety signals were identified, and at-home administration may reduce treatment burden

The FDA has approved Genentech’s Enspryng (satralizumab-mwge) for the treatment of adults with thyroid eye disease (TED), making it the first and only subcutaneous treatment for the condition that can be administered at home.

According to the company, patients or caregivers can administer Enspryng following training by a healthcare provider, offering an alternative to infusion-based treatment. 

“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 approval follows a priority review and is supported by results from the phase 3 SatraGO clinical program, comprising of SatraGO-1 (NCT05987423) and SatraGO-2 (NCT06106828). The randomized, placebo-controlled, multicenter studies enrolled 258 patients across 19 countries, including adults with active, moderate-to-severe TED and chronic TED. The primary endpoint was the proportion of patients with active TED achieving a reduction in proptosis of at least 2 mm in the study eye at week 24.

Although SatraGO-1 did not meet its prespecified primary efficacy endpoint, SatraGO-2 demonstrated significant improvements in proptosis and diplopia among patients with active TED.

In SatraGO-2, 52.9% of patients receiving Enspryng achieved a proptosis response compared with 23.4% receiving placebo. Diplopia reduction was reported in 60.7% of patients treated with Enspryng versus 25.8% in the placebo group.

According to Genentech, consistent efficacy results were observed in the overall SatraGO-2 population, which included patients with active and chronic TED.

No new safety signals were identified in either study, and the safety profile remained consistent with previous experience in neuromyelitis optica spectrum disorder (NMOSD).

The approval represents Enspryng’s second FDA-approved indication, following its 2020 approval for neuromyelitis optica spectrum disorder (NMOSD). This follows a recent acceptance by the FDA for priority review in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Enspryng is also being studied in additional neurological autoimmune and inflammatory diseases that may benefit from inhibition of IL-6 mediated signaling. The therapy targets interleukin-6 receptor signaling and is also under investigation for other autoimmune and inflammatory conditions.

Enspryng is third pharmocologic treatment approved for TED, joining Horizon Therapeutics' Tepezza (teprotumumab-trbw), which was approved in 2020, and Viridian Therapeutics' Lumvoa (veligrotug-vvze), which was approved in June of this year.