Sling Therapeutics Raises $123M to Advance Oral Thyroid Eye Disease Drug
- Sling Therapeutics closed a $123 million Series C led by Forbion, joined by existing investor TPG Life Sciences Innovations and new investor Sectoral Asset Management.
- Proceeds will fund Phase 3 development of linsitinib, Sling's oral small-molecule IGF-1R inhibitor, for thyroid eye disease (TED).
- Unlike IV monoclonal antibodies that bind IGF-1R directly, such as Amgen's Tepezza and Viridian's Lumvoa, linsitinib is taken orally and affects IGF-1R phosphorylation, offering a potentially safer, more durable, more convenient option.
- Sling has begun dosing patients in its global pivotal Phase 3 ORBIT trial in moderate-to-severe active TED, building on its completed Phase 2b/3 LIDS trial, which met its efficacy goal.
- The financing positions Sling to compete against an established blockbuster IV therapy market for TED.
Tepezza is a multi-billion-dollar franchise that helped justify Amgen's $27.8B Horizon Therapeutics acquisition — so an oral challenger here isn't just chasing an indication, it's chasing the economics that made that deal work. Forbion leading a $123M round through Phase 3, with TPG re-upping and Sectoral joining fresh, signals real conviction in the differentiation thesis itself, not just TED as a hot category. The commercial logic is straightforward: IV infusions carry site-of-care burden, scheduling friction, and infusion-reaction risk that a pill sidesteps — real value in a chronic, relapsing disease where compliance matters. But incumbents hold prescriber relationships and entrenched reimbursement pathways; an oral entrant more likely peels off infusion-averse or relapsed patients first than displaces frontline share outright, unless Phase 3 data show a decisive edge.
Sling reels in $123M series C to fund oral Tepezza rival through phase 3 trial ↗