Sling Therapeutics Secures $123M to Fund Phase 3 Trial for Oral Thyroid Eye Disease Drug

Sling Therapeutics has secured $123 million in a Series C financing round to advance its oral drug candidate, linsitinib, into a global Phase 3 trial for the treatment of thyroid eye disease (TED). The funding positions the company to challenge existing injectable treatments for the rare autoimmune condition.

Funding and Trial Advancement

The financing was led by Forbion and included participation from new investor Sectoral Asset Management and existing investor TPG Life Sciences Innovations. The proceeds are designated to fund the Phase 3 ORBIT trial, a global study enrolling adults with moderate to severe active TED.

Sling Therapeutics said the trial's design was established in agreement with the U.S. Food and Drug Administration (FDA) following an End-of-Phase 2 meeting earlier this year. "The data generated to date give us confidence in linsitinib’s potential to meaningfully address important limitations of current TED therapies," said Sling Chief Executive Ryan Zeidan.

Linsitinib's Clinical Profile

Linsitinib is an oral medication that targets the insulin-like growth factor 1 receptor (IGF-1R), a validated target in TED that is also used by currently approved therapies. The drug's oral delivery method distinguishes it from existing treatments, which require infusion or injection.

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A completed Phase 2b/3 trial met its primary endpoint of reducing proptosis, the forward bulging of the eyes characteristic of the disease. According to the company, the drug also demonstrated a favorable safety profile with fewer concerns related to:

• Hearing impairment
• Blood sugar changes
• Menstrual cycle alterations

Market and Regulatory Context

The FDA has granted linsitinib Fast Track designation, a status intended to facilitate the development and expedite the review of drugs to treat serious conditions and fill an unmet medical need. This can lead to more frequent agency interactions and eligibility for accelerated approval and priority review.

Thyroid eye disease is a rare condition that affects more than 200,000 people in the United States, primarily women with Graves' disease. The condition causes inflammation and tissue buildup behind the eyes, which can impair vision in severe cases. Linsitinib has been evaluated in over 900 patients across 15 clinical trials for various diseases, according to Sling.