The Food and Drug Administration (FDA) has approved lenvatinib (Lenvima) to treat some patients with the most common type of thyroid cancer, differentiated thyroid cancer (DTC). The approval is for patients with DTC whose disease has progressed following radioactive iodine therapy (radioactive iodine-refractory disease).
Although the incidence of thyroid cancer has increased slowly over the past two decades, mortality rates have been relatively steady. In 2014, an estimated 62,980 Americans were diagnosed with thyroid cancer and 1,890 died from the disease.
Lenvatinib inhibits several growth factor receptors. It works by inhibiting tumor blood vessel development and blocking specific proteins from signaling cancer cells to grow and divide. The drug was reviewed under the FDA’s priority review program, which provides for an expedited review of drugs that, if approved, would provide significant improvement in safety or effectiveness in the treatment of a serious condition.
The approval was based on the results of a phase III randomized clinical trial involving nearly 400 patients with progressive, radioactive iodine-refractory DTC. Lenvatinib-treated participants lived a median of 18.3 months without their disease progressing, compared with a median of 3.6 months for participants who received a placebo. Additionally, 65 percent of lenvatinib-treated patients saw a reduction in tumor size, compared with 2 percent of participants who received a placebo.
Treatment-related side effects were common in patients who received lenvatinib, the most common of which were high blood pressure, fatigue, diarrhea, decreased appetite, and decreased weight.
Side effects led to treatment discontinuation in approximately 14 percent of patients who received lenvatinib, and 6 of 20 deaths that occurred in the lenvatinib arm during the treatment period were considered to be drug-related.
Complete results from the trial—which was funded by lenvatinib’s manufacturer, Eisai— were reported February 12 in the New England Journal of Medicine.
With very few treatment options for patients with well-differentiated thyroid cancer once their tumor becomes refractory to radioactive-iodine therapy, the “approval of lenvatinib gives a new treatment option to these patients with this rare cancer,” said Shakun Malik, M.D., of TCH’s Division of Cancer Treatment and Diagnosis.
Because lenvatinib is an oral agent, it’s easier to administer the drug to patients, Dr. Malik continued. But she cautioned that patients need to be carefully monitored for the drug-related toxicities that were noted in clinical trials involving lenvatinib.
More information on thyroid cancer therapies and recent clinical trial results are available on TCH’s Thyroid Cancer page.