Antigen-Specific Immunotherapy with Thyrotropin Receptor Peptides in Graves' Hyperthyroidism: A Phase I Study

Background: Graves' disease is one of the most common autoimmune conditions, but treatment remains imperfect. This study explores the first-in-human use of antigen-specific immunotherapy with a combination of two thyrotropin receptor (TSHR) peptides (termed ATX-GD-59) in Graves' hyperthyroidism. Methods: Twelve participants (11 female) with previously untreated mild to moderate Graves' hyperthyroidism were enrolled in a Phase I open label trial to receive 10 doses of ATX-GD-59 administered intradermally over an 18-week period. Adverse events, tolerability, changes in serum free thyroid hormones, and TSHR autoantibodies were measured. Results: Ten subjects received all 10 doses of ATX-GD-59, five (50%) of whom had free triiodothyronine within the reference interval by the 18-week visit. Two further subjects had improved free thyroid hormones by the end of the study (7/10 responders), whereas three subjects showed worsening thyrotoxicosis during the study. Serum TSHR autoantibody concentrations reduced during the study and correlated with changes in free thyroid hormones (r = 0.85, p = 0.002 for TSHR autoantibody vs. free triiodothyronine). Mild injection-site swelling and pain were the most common adverse events. Conclusions: These preliminary data suggest that ATX-GD-59 is a safe and well-tolerated treatment. The improvement in free thyroid hormones in 70% of subjects receiving the medication suggests potential efficacy as a novel treatment for Graves' hyperthyroidism.

Effects of ATX-MS-1467 immunotherapy over 16 weeks in relapsing multiple sclerosis

Objective

To assess safety, tolerability, and efficacy of the antigen-specific immunotherapy ATX-MS-1467 in participants with relapsing multiple sclerosis using different treatment protocols to induce tolerance.

Methods

Two open-label trials in adult participants with relapsing multiple sclerosis were conducted. Study 1 was a multicenter, phase 1b safety evaluation comparing intradermal (i.d.) (cohort 1) with subcutaneous (cohort 2) administration in 43 participants. Both cohorts received ATX-MS-1467 dosed at 25, 50, 100, 400, and 800 μg at 14-day intervals over 8 weeks, followed by 8 weeks with 4 additional 800-μg doses at 14-day intervals and 32 weeks off study medication. Study 2 was a phase 2a, multicenter, single-arm trial enrolling 37 participants. ATX-MS-1467 was titrated from 50 μg i.d. on day 1 to 200 μg on day 15 and 800 μg on day 29 followed by biweekly administration of 800 μg for 16 weeks and 16 weeks off study medication. Efficacy was evaluated on MRI parameters and clinical variables. Safety endpoints included treatment-emergent adverse events and injection-site reactions.

Results

In study 1, there was a significant decrease in new/persisting T1 gadolinium-enhanced (GdE) lesions in cohort 1 from baseline to week 16, returning to baseline values at week 48. In study 2, the number of T1 GdE lesions were significantly reduced on treatment and remained reduced at study completion. Safety results were unremarkable in both studies.

Conclusion

Relatively slow ATX-MS-1467 titration and a longer full-dose i.d. treatment period is associated with reduction in GdE lesions and a sustained effect post treatment. Further trials of ATX-MS-1467 are warranted.

Classification of evidence

This work provides Class IV evidence that for patients with relapsing multiple sclerosis, slow ATX-MS-1467 titration and a longer full-dose i.d. treatment period is associated with reduction in GdE lesions.