Modified-release recombinant human TSH (MRrhTSH) augments the effect of (131)I therapy in benign multinodular goiter: results from a multicenter international, randomized, placebo-controlled study.

Background: Recombinant human TSH (rhTSH) can be used to enhance 131I therapy for shrinkage of multinodular goiter (MG). Objective, Design, and Setting: The objective of the study was to compare the efficacy and safety of 0.01 and 0.03 mg modified-release (MR) rhTSH as an adjuvant to 131I therapy, vs. 131I alone, in a randomized, placebo-controlled, international, multicenter study. Patients and Intervention: Ninety-five patients (57.2 ± 9.6 yr old, 85% females, 83% Caucasians) with MG (median size 96.0, range 31.9-242.2 ml) were randomized to receive placebo (group A, n = 32), MRrhTSH 0.01 mg (group B, n = 30), or MRrhTSH 0.03 mg (group C, n = 33) 24 h before a calculated activity of 131I. Main Outcome Measures: The primary end point was a change in thyroid volume (by computerized tomography scan, at 6 months). Secondary end points were the smallest cross-sectional area of the trachea; thyroid function tests; Thyroid Quality of Life Questionnaire; electrocardiogram; and hyperthyroid symptom scale. Results: Thyroid volume decreased significantly in all groups. The reduction was comparable in groups A and B (23.1 ± 8.8 and 23.3 ± 16.5%, respectively; P = 0.95). In group C, the reduction (32.9±20.7%) wasmorepronounced than in groupsA(P=0.03) and B. The smallest cross-sectional area of the trachea increased in all groups: 3.8 ± 2.9% in A, 4.8 ± 3.3% in B, and 10.2 ± 33.2% in C, with no significant difference among the groups. Goiter-related symptoms were effectively reduced and there were no major safety concerns. Conclusion: In this dose-selection study, 0.03 mg MRrhTSH was the most efficacious dose as an adjuvant to 131I therapy of MG. It was well tolerated and significantly augmented the effect of 131I therapy in the short term. Larger studies with long-term follow-up are warranted