Sling Therapeutics raised $123 million in a Series C to support its Phase 3 confirmatory study for linsitinib, an oral treatment targeting thyroid eye disease. The financing was led by Forbion with participation from TPG Life Sciences Innovations and Sectoral Asset Management. Sling recently started the Phase 3 Orbit trial comparing linsitinib 150 mg twice daily versus placebo in approximately 130 patients with moderate to severe active thyroid eye disease. The company has positioned linsitinib as an oral alternative to approved injectable therapies. The funding and Phase 3 initiation add competitive pressure in thyroid eye disease, an area where convenience and safety profiles can be decisive in payer and clinician adoption.