Anlotinib for the Treatment of Patients with Locally Advanced or Metastatic Medullary Thyroid Cancer

Background: The prognosis of advanced or metastatic medullary thyroid carcinoma (MTC) is poor, and there are few therapeutic options. Anlotinib has previously shown promising antitumor activity on MTC in preclinical models and a Phase I study. This Phase II clinical trial was devised to confirm the antitumor activity of anlotinib in patients with advanced or metastatic MTC. Methods: Patients with unresectable locally advanced or metastatic MTC received once daily oral anlotinib 12 mg, two weeks on/one week off, until disease progression, death, unacceptable toxicity, or withdrawal of consent for any reason. The dose was adjusted on the basis of observed toxicity. The primary endpoint was progression-free survival (PFS). Results: Fifty-eight patients received anlotinib treatment. The primary endpoint PFS has not yet been reached at the time of analysis. On the basis of investigator assessments, 56.9% of patients experienced a partial response. PFS rate at 48 weeks was 85.5%. Forty-five patients had a ≥50% decrease in serum calcitonin concentration from baseline. The most common adverse events were hand-foot syndrome, hypertriglyceridemia, cholesterol elevation, fatigue, and proteinuria. Conclusions: Anlotinib demonstrated a durable antitumor activity with a manageable adverse event profile in locally advanced or metastatic MTC.