Immunovant has unveiled compelling six-month off-treatment data for batoclimab in uncontrolled Graves' disease patients, demonstrating what the company describes as the first potentially disease-modifying therapy for this autoimmune condition. The results show sustained therapeutic benefits well beyond the treatment period, with 80% of patients maintaining normal thyroid function six months after completing therapy.
Sustained Response in Majority of Patients
The proof-of-concept study enrolled 25 patients with active Graves' disease, characterized by elevated thyrotropin receptor autoantibodies (TRAb) and hyperthyroidism despite anti-thyroid drug (ATD) therapy. Of the 21 patients who entered the six-month off-treatment follow-up period, approximately 80% (17/21) demonstrated response, maintaining T3 and T4 levels at or below the upper limit of normal at the end of the six-month follow-up period.
"These novel and encouraging results support FcRn blockade as a potentially effective mechanism for the treatment of Graves' disease, with the six-month remission data providing evidence of potential disease modification," said George Kahaly, M.D., Ph.D., Lead Principal Investigator.
Drug-Free Remission Achieved in Half of Responders
Among the 17 patients who responded to therapy, approximately 50% (8/17) achieved anti-thyroid drug-free remission at six months following the end of batoclimab treatment. An additional 30% (5/17) required only minimal ATD doses of 2.5 mg/day, despite what researchers noted was a suboptimal step-down dosing design during the treatment period.
Eric Venker, M.D., Pharm.D., CEO of Immunovant, emphasized the clinical significance: "We are incredibly excited to present these remission data demonstrating strong durability of response and ATD-free remission in previously uncontrolled patients off-treatment for six months. We believe these data have the potential to be transformative for patients and practice-changing for physicians, if approved by FDA, by addressing a significant unmet need in Graves' disease."
Study Design and Treatment Protocol
The study employed a 24-week treatment period with batoclimab, Immunovant's first-generation fully human monoclonal antibody targeting FcRn. Patients received a dose step-down regimen: 680 mg weekly subcutaneously for weeks 0-12, followed by 340 mg weekly for weeks 12-24. This treatment phase was followed by a 24-week off-treatment follow-up period to assess durability of response.
The key endpoint measured the proportion of participants achieving normalization of free triiodothyronine (T3) and free thyroxine (T4) or levels below the lower limit of normal at Week 24, without requiring an increase in ATD dose from baseline. Safety and tolerability profiles were consistent with prior batoclimab studies.
Advancing to Registrational Trials
Building on these proof-of-concept results, Immunovant is advancing its next-generation compound IMVT-1402 into two potentially registrational global trials for Graves' disease. These studies will evaluate a 600 mg dose administered for up to 52 weeks without dose reduction, addressing the suboptimal step-down design limitation identified in the current study.
Both registrational trials are currently enrolling patients, with topline readouts expected in 2027. The data will be presented at the 2025 Annual Meeting of the American Thyroid Association on September 11, 2025.
Mechanism and Clinical Implications
Batoclimab works by targeting the neonatal Fc receptor (FcRn), which plays a crucial role in antibody recycling and maintenance of pathogenic autoantibodies in Graves' disease. The sustained response observed months after treatment cessation suggests the therapy may offer disease-modifying effects rather than merely symptomatic control.
The results represent a potential paradigm shift for patients with uncontrolled Graves' disease, a population with significant unmet medical needs who continue to experience hyperthyroidism despite conventional anti-thyroid drug therapy. If approved, this approach could offer the first disease-modifying treatment option for these patients.
