Purpose: Positive results of phase I studies evaluating lenvatinib in solid tumors, including thyroid cancer, prompted a phase II trial in advanced medullary thyroid carcinoma (MTC).Experimental Design: Fifty-nine patients with unresectable progressive MTC per Response Evaluation Criteria In Solid Tumors (RECIST) v1.0 within the prior 12 months received lenvatinib (24-mg daily, 28-day cycles) until disease progression, unmanageable toxicity, withdrawal, or death. Prior anti-VEGFR therapy was permitted. The primary endpoint was objective response rate (ORR) by RECIST v1.0 and independent imaging review.Results: Lenvatinib ORR was 36% [95% confidence interval (CI), 24%–49%]; all partial responses. ORR was comparable between patients with (35%) or without (36%) prior anti-VEGFR therapy. Disease control rate (DCR) was 80% (95% CI, 67%–89%); 44% had stable disease. Among responders, median time to response (TTR) was 3.5 months (95% CI, 1.9–3.7). Median progression-free survival (PFS) was 9.0 months (95% CI, 7.0–not evaluable). Common toxicity criteria grade 3/4 treatment-emergent adverse events included diarrhea (14%), hypertension (7%), decreased appetite (7%), fatigue, dysphagia, and increased alanine aminotransferase levels (5% each). Ret proto-oncogene status did not correlate with outcomes. Low baseline levels of angiopoietin-2, hepatocyte growth factor, and IL8 were associated with tumor reduction and prolonged PFS. High baseline levels of VEGF, soluble VEGFR3, and platelet-derived growth factor BB, and low baseline levels of soluble Tie-2, were associated with tumor reduction.Conclusions: Lenvatinib had a high ORR, high DCR, and a short TTR in patients with documented progressive MTC. Toxicities were managed with dose modifications and medications. Clin Cancer Res; 22(1); 44–53. ©2015 AACR.

The effect(s) of hypothyroidism on adult brain cognitive function are poorly understood. We performed a series of neuropsychological tests in 13 thyroid cancer patients while they continued to take their usual dose of levothyroxine (LT₄) and again after discontinuing thyroid hormone. Three euthyroid subjects were also tested twice to assess the effect of repeated testing on performance. The tests assessed memory, mood, and attentional resources and controlled for the practice effects of repeated testing. The mean thyrotropin (TSH) on LT₄ was 0.56 ± 0.76 mU/L and while hypothyroid was 69 ± 33 mU/L. While hypothyroid, the mean Beck depression score was significantly higher (15.31 ± 9.41 hypothyroid vs. 7.31 ± 4.82 on LT₄) and the subjects rated themselves worse relative to functional memory, concentration, thinking, alertness, and motivation. Hypothyroidism was associated with a decrease in retrieval from memory (p = 0.0034), and this effect could not be attributed to depression or to practice effects. Thyroid state did not affect immediate recall, verbal learning, inhibitory efficiency, information processing speed, or attention switching. Athyrosis is associated with a decrement in delayed recall of verbal information but not in other objective measures of cognition, suggesting that the memory decrement of hypothyroidism is not caused by a generalized reduction in attentional resources.

—Thyroid hormone regulation of the cardiac pacemaker gene, the hyperpolarization-activated cyclic nucleotide-gated channel gene (HCN2), was studied in rats by Northern analysis. Thyroid hormone administration to hypothyroid rats resulted in a doubling of the HCN2/β-actin mRNA ratio. A smaller, not statistically significant, increase in HCN2 mRNA occurred when euthyroid animals were made hyperthyroid. A single large dose of l -triiodothyronine given to hypothyroid rats caused a 4.7-fold increase in myocardial HCN2 mRNA expression level and only a 2.3-fold increase in the β-actin mRNA level. Although the rat HCN2 promoter has not been cloned, we identified a consensus thyroid hormone response element in the promoter sequence of the human HCN2 gene. Therefore, the increase in rat HCN2 mRNA is likely due to l -triiodothyronine stimulation of HCN2 gene transcription. The results suggest that the regulation of heart rate by thyroid hormone may be explained, at least in part, by the positive effect of this hormone on HCN2 gene expression.