Batoclimab Induces Very Rapid and Sustained Post-treatment Euthyroidism in Graves

George Kahaly; Jan Wolf; Anna-Lena Ganz; Maximilian Luffy; Katherine Albert; Farah Ali; E Lin; Julie Howard; William Macias

doi:10.1530/endoabs.117.OC4.5

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Endocrine Abstracts (2026) 117 OC4.5 | DOI: 10.1530/endoabs.117.OC4.5

SFEBES2026 Oral Communications Thyroid (6 abstracts)

Batoclimab Induces Very Rapid and Sustained Post-treatment Euthyroidism in Graves’ Disease

George Kahaly ¹ , Jan Wolf ¹ , Anna-Lena Ganz ¹ , Maximilian Luffy ¹ , Katherine Albert ² , Farah Ali ² , E Lin ² , Julie Howard ² & William Macias ²

Author affiliations

¹Department of Medicine I, Johannes Gutenberg University Medical Center, Mainz, Germany; ²Immunovant, Inc., New York, NY, USA

Objectives: To report post-treatment outcomes among hyperthyroid patients with Graves’ disease (GD) who received batoclimab, a neonatal fragment crystallizable receptor blocker, in a phase 2a, proof-of-concept open-label study.

Methods: Overtly hyperthyroid GD patients with elevated thyrotropin receptor autoantibodies (TSH-R-Ab) despite ≥12 weeks on moderate-to-high dose antithyroid drugs (ATD) were eligible. Participants received weekly subcutaneous injections of batoclimab for 24 weeks (Weeks 0-11, 680 mg; Weeks 12-23, 340 mg). At Week 24, participants with FT3/FT4 ≤upper limit of normal (ULN) entered a 24-week batoclimab-free follow-up period (Weeks 24-48).

Results: By Week 2, 15/25 (60%) patients achieved FT3/FT4 ≤ULN without increasing ATD dose. This increased to 20/25 (80%) patients at Week 12 or end of high-dose treatment, including 15 (60%) who were off ATD, and to 18 (72%) patients at Week 24 or end of treatment (EOT), including 10 (40%) who were off ATD. Six months following EOT, 17/25 (68%) patients had FT3/FT4 ≤ULN; of these, 8 were off ATD and 5 were on ≤2.5 mg ATD/day. Mean (SD) TSH increased from 0.01 (0.01) mIU/l at baseline to 0.32 (0.61) and 0.77 (0.85) mIU/l at Weeks 24 and 48, respectively. Mean (SD) TSH-R-Ab levels decreased from 17.96 (12.12) IU/l at baseline to 8.13 (8.82), 6.16 (8.85), and 9.94 (12.03) IU/l at Weeks 2, 24, and 48, respectively (P < 0.0001 vs baseline for all). Total IgG rebounded after treatment stopped, with a mean (SD) level of 11.72 (2.64) g/l at baseline compared to 4.10 (1.76) g/l at Week 24 (P < 0.001) and 11.14 (2.78) g/l at Week 48 (P = 0.42). Batoclimab was well tolerated with no new safety signals.

Conclusions: Batoclimab resulted in rapid and sustained normalization of FT3/FT4. Six months after stopping treatment, 52% of patients remained euthyroid either off ATD or on ≤2.5 mg ATD/day.