Anlotinib in patients with medullary thyroid carcinoma with negative prognostic factors: A sub-analysis based on the ALTER01031 study

BACKGROUND: Medullary thyroid carcinoma (MTC) is a rare type of thyroid cancer; however, it accounted for 13.4% of the disease-specific mortalities. ALTER01031 (NCT02586350) was a randomised, placebo-controlled phase 2b trial that evaluated the efficacy and safety of anlotinib in locally advanced or metastatic MTC. This post hoc analysis aimed to evaluate the efficacy and safety of anlotinib in older patients and those with bone metastases using ALTER01031. METHODS: In ALTER01031, anlotinib significantly prolonged the median progression-free survival (PFS) from 11.1 months to 20.7 months compared with placebo in the whole population. Patients who were older (≥ 50 years) or had bone metastases were selected. PFS and overall survival (OS) were estimated and compared between patients receiving anlotinib or placebo in each subgroup. A sub-analysis of tumour response and safety was also performed. RESULTS: Patients with older age or bone metastases experienced rapid disease progression as the median PFS was 6.8 months and 7.0 months respectively in the placebo group. Anlotinib significantly improved the median PFS to 17.5 months (P = 0.002) and 20.7 months (P = 0.029) with hazard ratio (HR) of 0.31 (95% CI, 0.15–0.68) and 0.44 (95% CI, 0.20–0.94) compared with placebo. Significant benefit in OS was observed in patients with older age after a longer follow-up (HR = 0.47 [95% CI, 0.22–0.99], P = 0.041). The safety profile of these subgroups was similar to that of the entire population. CONCLUSION: This sub-analysis demonstrated significant survival benefits and favourable safety of anlotinib in patients with MTC who had old age or bone metastases, supporting the feasibility of anlotinib in these patients.