FDA Approves New Thyroid Cancer Treatment
About nine out of 10 U.S. thyroid cancer diagnoses are differentiated thyroid cancers; the FDA approval provides a new treatment option for certain patients with this form of the disease.
For thousands of people diagnosed with differentiated thryroid cancer, particularly those in whom it has spread, there was nothing unlucky about Friday, Feb. 13, 2015.
In fact, the U. S. Food and Drug Administration (FDA) provided them with welcome news, announcing approval of lenvatinib, sold under the brand name Lenvima, for the treatment of patients with locally recurrent or metastatic differentiated thyroid cancer that has progressed despite radioactive iodine therapy.
The National Cancer Institute defines differentiation as the processes through which immature cells become mature cells with specific functions. Well-differentiated cancer cells look more like normal cells and tend to grow and spread more slowly than poorly differentiated or undifferentiated cancer cells. Differentiated thyroid cancers account for approximately nine out of every 10 of the nearly 63,000 thyroid cancer diagnoses that are made in the U.S. each year. Although the five-year survival rate for all U.S. patients diagnosed with thyroid cancer is almost 98 percent, it falls to just below 55 percent for those with metastatic disease.
Lenvatinib is the second molecularly targeted therapeutic approved by the FDA for treating differentiated thyroid cancer. The first, sorafenib, sold under the brand name Nexavar, was approved for this use in November 2013.
Like sorafenib, lenvatinib targets several molecules that promote the growth of differentiated thyroid cancers in various ways. Among these molecules are families of molecules involved in the growth of new blood and lymphatic vessels, a process called angiogenesis, which supports tumor growth and survival. The families include the vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) receptor families. Lenvatinib also inhibits other molecules that have been implicated in tumor growth and cancer progression, including KIT and RET.
The FDA approval of lenvatinib was based on results from the randomized, double-blind, phase III study of (E7080) lenvatinib in differentiated cancer of the thyroid (SELECT) clinical trial, which were recently published in the New England Journal of Medicine. In this trial, lenvatinib increased more than five-fold the time to disease progression: progression-free survival was 18.3 months for patients who received lenvatinib versus 3.6 months for those who received placebo.
In addition, 65 percent of patients who received lenvatinib saw a reduction in tumor size, compared with 2 percent of those who received placebo.
Given that angiogenesis is known to have an important role in promoting the growth of other solid tumors, lenvatinib is currently being tested in clinical trials as a potential treatment for a number of other types of cancers, including kidney cancer, liver cancer, and non-small cell lung cancer.
