Axitinib-Induced Hypothyroidism as a Predictor of Long-Term Survival in Patients with Metastatic Renal Cell Carcinoma.

ABSTRACT

BACKGROUND: The side effects of sunitinib, namely onset of hypertension and hypothyroidism, have been reported to be predictive biomarkers of treatment efficacy. However, the relationship between hypothyroidism and prolongation of survival in treatment with axitinib, a drug similar to sunitinib, has not yet been reported. OBJECTIVE: In this study, we examined the relationship between the onset of hypothyroidism caused by axitinib and overall survival (OS) and progression-free survival (PFS). METHODS: In this retrospective study, 44 Japanese patients, including 30 men and 14 women, were enrolled. The average age of subjects in this study was 67 years. RESULTS: During treatment, 68% of patients developed hypothyroidism, with an average peak thyroid-stimulating hormone (TSH) value of 15.7 mIU/L. Patients with TSH > 4 mIU/L and required thyroid hormone regulation with levothyroxine had prolonged PFS (11.1 vs. 3.5 months; p = 0.002) and OS (26.4 vs. 15.6 months; p = 0.02). Hypothyroidism was found to be a significant side effect of axitinib in patients with metastatic renal cell carcinoma (mRCC). Patients with hypothyroidism had significantly longer PFS and OS. CONCLUSION: Our findings indicate that hypothyroidism may be a predictive marker of therapeutic effect of axitinib against mRCC.