Blocking the TSH receptor with K1-70™ in a patient with follicular thyroid cancer, Graves' disease and Graves' ophthalmopathy

Abstract

Background We report therapeutic use of K1-70™, a TSH receptor (TSHR) antagonist monoclonal antibody, in a patient with follicular thyroid cancer (FTC), Graves' disease (GD) and Graves' ophthalmopathy (GO). Methods A 51-year old female patient who smoked, presented in October 2014 with FTC complicated by GD, high levels of TSHR autoantibodies with high thyroid stimulating (TSAb) activity and severe GO. K1-70™ was administered at 3-weekly intervals with the dose adjusted to block TSAb activity. Her cancer was managed with lenvatinib and radioiodine therapy. Results Following initiation of K1-70™ therapy TSAb activity measured in serum decreased and GO (proptosis and inflammation) improved. On K1-70™ monotherapy during the pause in lenvatinib several metastatic lesions stabilised while others showed progression attenuation compared to that prior to lenvatinib therapy. Conclusions These observations suggest that blocking TSHR stimulation with K1-70™ can be an effective treatment for GO and may also benefit select patients with FTC and GD.