The FDA has approved satralizumab (Enspryng) as the first and only at-home subcutaneous treatment for adults with thyroid eye disease (TED), according to developer Roche. The drug is a humanized monoclonal antibody that binds to both soluble and membrane-bound interleukin-6 receptors, blocking IL-6-mediated inflammatory signaling. TED is a rare autoimmune condition often linked to hyperthyroidism, causing symptoms such as proptosis, double vision, eye swelling, and potentially blinding complications.
The approval was based on the phase III SatraGO-1 and SatraGO-2 trials, which enrolled 258 patients across 19 countries. In SatraGO-2, 52.9% of treated patients with active TED achieved at least a 2 mm reduction in proptosis versus 23.4% on placebo, and 60.7% versus 25.8% saw improvement in double vision. However, SatraGO-1 did not meet its prespecified primary efficacy endpoint at week 24. Roche said results were consistent across the overall population, which included patients with chronic TED.
No new safety signals emerged; the most common adverse events were upper respiratory tract infections and elevated alanine aminotransferase levels. The drug is contraindicated in patients with active or untreated latent tuberculosis and active hepatitis B, and screening for hepatitis B, tuberculosis, and liver enzymes is required before the first dose. Dosing begins with three injections at weeks 0, 2, and 4, followed by maintenance doses every four weeks, and patients or caregivers can administer it after training.
Two other non-surgical TED treatments, teprotumumab (Tepezza) and veligrotug (Lumvoa), are approved but given intravenously and target the insulin-like growth factor 1 receptor. Satralizumab's subcutaneous route and different mechanism may reduce the logistical burden of infusion-based care, though the failed SatraGO-1 trial tempers the otherwise positive efficacy picture. Roche is also studying the drug in other neurologic, autoimmune, and inflammatory diseases. [Source: MedPage Today]