Austin, Texas, USA, September 16, 2026
Sling Therapeutics, Inc. has announced that the first patients have been dosed in the global Phase 3 ORBIT pivotal trial evaluating linsitinib as a potential treatment for thyroid eye disease (TED). The milestone marks the transition of linsitinib into late-stage clinical development and represents an important step in Sling Therapeutics’ effort to develop a new oral treatment for patients affected by this autoimmune eye disorder. The randomized, double-blind, placebo-controlled ORBIT study is designed to evaluate the efficacy and safety of linsitinib in adults with active, moderate-to-severe TED. The company expects the global trial to enroll patients across multiple countries and generate the pivotal clinical evidence needed to support potential regulatory submissions, subject to successful results.
Global Phase 3 ORBIT Trial Begins
The ORBIT Phase 3 trial is a pivotal study designed to evaluate linsitinib in adults with active, moderate-to-severe thyroid eye disease. The study will compare linsitinib with placebo while assessing clinical outcomes relevant to the severity and activity of TED. As a late-stage trial, ORBIT is intended to provide confirmatory evidence regarding the candidate’s benefit-risk profile and could represent a key step toward potential regulatory approval. Sling Therapeutics stated that the trial will be conducted globally, expanding participation beyond a single geographic region. The international design is intended to support a broad evaluation of linsitinib across diverse patient populations and healthcare settings. The company is targeting approximately 600 participants for the pivotal program. The first-patient dosing milestone follows earlier clinical development work evaluating linsitinib in TED. Data generated during previous studies have provided the basis for advancing the candidate into Phase 3, while the ORBIT program will provide a larger dataset for evaluating clinical efficacy and safety.
Linsitinib Targets IGF-1R Pathway in TED
Linsitinib is an oral small-molecule inhibitor of the insulin-like growth factor 1 receptor (IGF-1R), a biological target associated with the pathophysiology of thyroid eye disease. IGF-1R signaling has been implicated in interactions between immune cells and orbital tissues in TED, contributing to inflammation and tissue remodeling around the eyes. Thyroid eye disease is an autoimmune disorder associated with thyroid dysfunction in which inflammation and enlargement of tissues surrounding the eyes can cause symptoms such as eye pain, swelling, redness, double vision and changes in appearance. In more severe cases, TED can affect visual function and significantly interfere with quality of life.
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By targeting IGF-1R, Sling Therapeutics is investigating whether linsitinib can influence the underlying biological processes contributing to TED. The oral route of administration is also intended to provide a treatment option that differs from therapies requiring intravenous infusion or other administration approaches. The candidate’s mechanism and clinical performance will continue to be evaluated through the Phase 3 ORBIT program. While earlier studies provide the rationale for further development, Phase 3 results will be critical in determining whether linsitinib can demonstrate clinically meaningful efficacy and an acceptable safety profile.
Late-Stage Development Advances TED Treatment Research
The initiation of ORBIT represents a significant milestone in the development of potential new therapies for thyroid eye disease, particularly for patients with active moderate-to-severe disease. Current management can involve medications, immunomodulatory treatments, radiation therapy or surgery depending on disease severity and stage. Continued research is focused on developing therapies that can address the inflammatory and tissue-remodeling processes underlying TED. Sling Therapeutics is developing linsitinib with the objective of providing an oral, targeted treatment approach. The company’s advancement into a global pivotal Phase 3 study reflects the increasing clinical interest in targeted therapies for autoimmune ophthalmic disorders.
The ORBIT study is expected to provide additional information on treatment response, disease activity, eye-related outcomes and safety. Researchers will also evaluate whether the benefits observed during earlier development can be replicated in a larger patient population. Successful completion of the Phase 3 program could support future discussions with regulatory authorities and potentially provide the foundation for marketing applications. However, linsitinib remains an investigational therapy, and its efficacy and safety have not yet been established for regulatory approval. The first patients dosed in ORBIT therefore mark the beginning of an important late-stage clinical evaluation. As Sling Therapeutics progresses with the global trial, future clinical data will help determine the potential role of linsitinib in the treatment of thyroid eye disease and contribute to the broader development of targeted therapies for autoimmune eye disorders.
Source: Sling Therapeutics press release
