Proposed section structure
For this topic, a clinically appropriate structure is: Highlights; Disease burden and therapeutic rationale; Study design and methods; Efficacy results; Safety and tolerability; Clinical interpretation and limitations; Practice implications and future directions; Funding, disclosures, and citation.
Highlights
THRIVE is a global, multicenter, randomized, double-masked, placebo-controlled phase 3 trial evaluating veligrotug, a full antagonist monoclonal antibody targeting the insulin-like growth factor-1 receptor, in moderate-to-severe active thyroid eye disease.
After five intravenous infusions over 12 weeks, veligrotug produced large and statistically significant improvements versus placebo at week 15 across the major disease domains that matter clinically: proptosis, inflammatory activity, and diplopia.
The magnitude of benefit was notable. Proptosis responder rates reached 70% by Hertel exophthalmometry and 71% by MRI or CT, compared with 5% and 9% with placebo, respectively. Overall responder rate was 67% with veligrotug versus 5% with placebo.
Response appeared early, beginning at week 3, and durability was encouraging: 70% of initial proptosis responders maintained response through week 52. Treatment was generally well tolerated, with a 4% discontinuation rate and no serious treatment-related adverse events reported.
Disease burden and therapeutic rationale
Thyroid eye disease (TED), also called Graves’ orbitopathy, is a disfiguring and potentially vision-threatening autoimmune condition associated with thyroid autoimmunity. Its clinical burden extends far beyond orbital signs. Patients may experience proptosis, diplopia, pain, photophobia, soft-tissue inflammation, corneal exposure, impaired quality of life, and in severe cases compressive optic neuropathy. Even when visual function is preserved, the cosmetic and psychosocial consequences can be profound.
Management of active moderate-to-severe TED has historically relied on systemic glucocorticoids, orbital radiation in selected patients, and surgery during inactive phases. These approaches have important limitations. Steroids may improve inflammation but often have modest effects on proptosis and carry substantial metabolic, psychiatric, infectious, and musculoskeletal toxicities. Surgical rehabilitation remains essential for many patients but is invasive and generally deferred until disease quiescence. This creates a clear need for targeted disease-modifying therapy that can act during the active inflammatory phase and alter the trajectory of orbital remodeling.
The insulin-like growth factor-1 receptor (IGF-1R) has emerged as an important therapeutic target in TED biology. Orbital fibroblasts and immune signaling pathways implicated in TED show functional interactions involving IGF-1R and the thyrotropin receptor. Antagonizing IGF-1R is biologically plausible as a means of reducing fibroblast activation, tissue expansion, and inflammatory signaling within the orbit. Veligrotug is a full antagonist monoclonal antibody to IGF-1R and, in THRIVE, was tested in a rigorous phase 3 setting.
Study design and methods
THRIVE was a global, multicenter, randomized, double-masked, placebo-controlled phase 3 trial. Adult patients with moderate-to-severe active TED were eligible if disease onset was 15 months or less, proptosis was at least 3 mm above normal, and the clinical activity score (CAS) was at least 3. These criteria enriched for patients in the active, inflammatory stage in whom immunomodulatory therapy is expected to have the greatest effect.
Participants were randomized in a 2:1 ratio to receive either veligrotug 10 mg/kg or placebo every 3 weeks for a total of five intravenous infusions. This corresponds to a 12-week treatment course, with the primary efficacy assessment at week 15 and follow-up continued through week 52.
The primary endpoint depended on geographic region: either proptosis responder rate (PRR), defined as at least a 2-mm reduction by Hertel exophthalmometry, or overall responder rate (ORR), defined as PRR plus at least a 2-point reduction in CAS. While this regional variation complicates endpoint harmonization slightly, the trial also assessed a broad array of clinically important secondary endpoints, including proptosis measured by imaging, mean change in proptosis, diplopia improvement, and diplopia resolution.
A total of 113 patients received study treatment: 75 received veligrotug and 38 received placebo. Baseline characteristics were reported as balanced between groups, an important point in a trial of this size, where imbalances in activity, smoking, thyroid status, or baseline disease severity could materially affect interpretation.
Efficacy results
Rapid onset of benefit
One of the most clinically appealing findings is the early onset of efficacy. Improvements were observed as early as week 3. For practicing clinicians, this matters because active TED often evolves quickly, with high symptom burden and major quality-of-life impact. A therapy that shows measurable effect after the first infusion cycle may influence both treatment selection and patient adherence.
Primary and major secondary outcomes at week 15
At week 15, veligrotug significantly outperformed placebo across all reported primary and secondary efficacy endpoints, with P values less than 0.001. The consistency of benefit across multiple measures strengthens confidence that the observed effect is clinically real and not an artifact of a single endpoint definition.
By Hertel exophthalmometry, the proptosis responder rate was 70% with veligrotug versus 5% with placebo. This absolute difference of 65 percentage points is striking in a disease where reduction in forward globe displacement is difficult to achieve medically. The corresponding number needed to treat is approximately 2, underscoring the size of effect.
Using MRI or CT-based assessment, the proptosis responder rate was similarly robust: 71% with veligrotug versus 9% with placebo. The alignment between bedside exophthalmometry and cross-sectional imaging is reassuring, because it suggests that the effect is not simply measurement variability but reflects meaningful orbital tissue change.
The overall responder rate, which incorporated both proptosis reduction and improvement in inflammatory activity, was 67% with veligrotug and 5% with placebo. This is especially relevant because TED treatment should not be judged by appearance alone. Improvement in disease activity indicates an effect on the active autoimmune-inflammatory process, not just globe position.
Mean proptosis reduction was also clinically impressive. By Hertel exophthalmometry, the mean reduction was 2.90 mm with veligrotug compared with 0.48 mm with placebo. By MRI or CT, mean reduction was 2.96 mm versus 0.58 mm, respectively. In practical terms, a reduction approaching 3 mm can translate into visibly meaningful improvement for patients and may reduce subsequent reconstructive burden, although surgery may still be needed for some.
Diplopia outcomes
Diplopia is among the most functionally disabling manifestations of TED, often impairing reading, driving, and mobility. Veligrotug demonstrated substantial benefit in this domain as well. Diplopia improvement occurred in 59% of treated patients compared with 20% on placebo. Diplopia resolution was achieved in 49% versus 12%, respectively.
These findings are clinically important because anti-inflammatory benefit does not always translate into motility improvement. Restrictive myopathy and extraocular muscle enlargement can be difficult to reverse once established. The magnitude of benefit seen here suggests that intervening during the active phase may preserve or restore ocular alignment better than historical standards of care in at least a subset of patients.
Durability through week 52
Durability is central when considering whether a therapy changes disease course or simply suppresses activity transiently. In THRIVE, 70% of initial responders maintained proptosis response at week 52. Although the abstract does not provide a full time-course breakdown for all endpoints or a placebo-adjusted durability analysis, persistence of response one year after initiation is encouraging, especially after only five infusions.
From a translational standpoint, this raises the possibility that IGF-1R antagonism may interrupt pathobiologic mechanisms driving orbital expansion during active disease rather than merely providing short-lived symptom relief. Longer-term follow-up, retreatment data, and post-marketing experience would be helpful to define relapse patterns more precisely.
Safety and tolerability
Veligrotug was generally well tolerated in this trial. The treatment discontinuation rate was 4%, which is low for an intravenous biologic used in an autoimmune disorder. Most adverse events were mild and resolved. The abstract specifically notes that there were no serious treatment-related adverse events and no changes in the safety profile through week 52.
These findings are encouraging, but they should still be interpreted with appropriate caution. Phase 3 trials of this size are well suited to detect common and moderately frequent adverse events, but uncommon toxicities, rare infusion reactions, and subgroup-specific risks may only become apparent with larger exposure in practice. The abstract does not detail specific adverse event categories, laboratory abnormalities, or adverse events of special interest, so clinicians will need the full publication for granular safety interpretation.
Because IGF-1R-directed therapies may raise class-related questions around glucose metabolism, hearing effects, muscle symptoms, or other systemic issues depending on the specific agent, detailed adverse event reporting will be important for therapeutic positioning. The current report is reassuring, but not yet definitive for long-term comparative safety.
Clinical interpretation and limitations
THRIVE appears to provide strong evidence that veligrotug is effective in active moderate-to-severe TED. Several aspects strengthen the study. First, the randomized, placebo-controlled, double-masked design minimizes bias. Second, efficacy was demonstrated across objective anatomic measures, inflammatory response, and functional diplopia outcomes. Third, the rapid onset and one-year durability increase the treatment’s practical relevance.
The magnitude of proptosis improvement deserves emphasis. In TED, many medical therapies improve inflammation more readily than they improve proptosis. A nearly 3-mm mean reduction, with responder rates around 70%, represents a large treatment effect and supports the biologic importance of the IGF-1R pathway in this disease.
That said, several limitations should be kept in view. The sample size was modest at 113 treated patients, which is acceptable for TED but still limits precision for safety estimates and subgroup analysis. The abstract does not provide confidence intervals, which are important for understanding the precision of effect sizes. Nor does it specify performance across clinically relevant subgroups such as smokers versus nonsmokers, varying thyroid function status, prior steroid use, sex, race and ethnicity, or duration within the 15-month inclusion window.
The use of region-dependent primary endpoints is understandable from a regulatory standpoint but introduces some complexity when interpreting the trial globally. It would be useful to know whether treatment effects were fully consistent across regions, measurement approaches, and adjudication frameworks.
In addition, the comparator was placebo rather than active therapy such as intravenous glucocorticoids. As a result, THRIVE clearly establishes superiority over no targeted treatment, but it does not by itself define comparative effectiveness against current standard regimens or clarify sequencing relative to steroids, radiation, or surgery. Cost, access, infusion logistics, and payer policy will also influence real-world uptake.
Finally, while durability through week 52 is promising, TED can have a prolonged and variable course. Longer observation is needed to determine relapse rates, retreatment needs, and impact on later rehabilitative surgery.
Practice implications and future directions
If approved and broadly available, veligrotug could meaningfully expand the therapeutic armamentarium for active TED. The profile suggested by THRIVE is particularly attractive for patients with prominent proptosis and diplopia early in the active phase, when the opportunity to change disease trajectory is greatest. The relatively short five-infusion schedule may also be appealing to both patients and clinicians, provided safety remains favorable in wider use.
Several questions now become clinically important. First, how should veligrotug be positioned relative to existing targeted IGF-1R inhibition strategies and to systemic glucocorticoids? Second, which patients derive the greatest benefit: those with highly inflammatory disease, marked proptosis, early motility involvement, or specific biomarker profiles? Third, can treatment reduce the eventual need for decompression surgery or strabismus surgery? These are outcome measures that matter deeply to patients and health systems.
Future studies should include head-to-head or pragmatic comparative effectiveness designs, detailed patient-reported outcomes, and health economic analyses. Biomarker work may also help identify responders and optimize treatment timing. Because TED is a multidisciplinary disease, future evidence should integrate ophthalmology, endocrinology, oculoplastics, strabismus care, and thyroid management.
Current guideline frameworks for TED emphasize disease activity, severity, smoking cessation, euthyroid status, local ocular surface care, and escalation to immunomodulatory therapy in moderate-to-severe active disease. THRIVE supports the growing role of targeted pathway inhibition within that model. For clinicians, the key message is that significant improvements in both appearance and function may be achievable during the active phase with a biologically targeted approach.
Funding, disclosures, and trial reporting
The abstract states that proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of the article. Specific funding details and a ClinicalTrials.gov registration number are not included in the abstract provided here and should be verified in the full-text publication.
Conclusion
THRIVE positions veligrotug as a potentially important new treatment option for active moderate-to-severe thyroid eye disease. In a phase 3 randomized, double-masked, placebo-controlled trial, a five-infusion course over 12 weeks produced rapid and statistically significant improvements in proptosis, inflammatory activity, and diplopia, with benefit apparent by week 3 and durability extending through week 52 in most initial responders.
The efficacy signal is strong, particularly for proptosis, a domain in which medical therapy has historically been challenging. The safety profile reported in the abstract is favorable, with low discontinuation and no serious treatment-related adverse events. The main unanswered questions concern comparative effectiveness, long-term safety, relapse patterns, and optimal integration into TED treatment pathways. Even so, the results represent a substantial advance and suggest that IGF-1R antagonism remains a highly consequential therapeutic strategy in this disease.
References
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