SOURCES: Feb. 13, 2015, news release, U.S. Food and Drug Administration; Len Lichtenfeld, M.D., deputy chief medical officer, American Cancer Society; Feb. 12, 2015, New England Journal of Medicine
FRIDAY, Feb. 13, 2015 (HealthDay News) -- The U.S. Food and Drug Administration on Friday approved a new drug to treat progressive thyroid cancer that continues to worsen despite radioactive iodine therapy.
Results of a just-published clinical trial found that the oral drug Lenvima (lenvatinib) delayed progression of the disease almost five times longer than a placebo in people with recurring tumors.
Lenvima is a targeted therapy that fights thyroid cancer by deterring the growth of new blood vessels that could help feed the cancer, researchers said.
It delayed progression of advanced thyroid cancer by 18 months, compared with four months for patients treated with a placebo, the trial found.
Results of the study, which was funded by drug manufacturer Eisai, were published in the Feb. 12 issue of the New England Journal of Medicine.
Historically, radioactive iodine has been the only treatment available to people with advanced thyroid cancer, said study leader Dr. Steven Sherman. He professor and chair of Endocrine Neoplasia and Hormonal Disorders at the University of Texas MD Anderson Cancer Center in Houston.
Speaking in a center news release, Sherman said more than half of thyroid cancer patients do not respond to radioactive iodine treatment. In addition, thyroid cancers tend to develop resistance to radioactive iodine over time.
The international clinical trial for Lenvima enrolled almost 400 patients from 21 countries, all of whom had thyroid cancer that had spread and become resistant to radioactive iodine.
In addition to the nearly fivefold improvement in progression-free survival, the drug also appeared to be useful for treating more patients. About two-thirds of the patients given Lenvima responded either fully or partially to the drug.
"In our study, we not only saw a dramatic improvement in progression-free survival, there was also a 65 percent response rate -- almost unprecedented results for thyroid cancer patients with such advanced disease," Sherman said.
Lenvima does come with some serious side effects, however. They can include heart failure, blood clot formation, liver damage, kidney damage, headache, confusion, seizures and visual changes, among other problems, the FDA said Friday in a news release.
The impact of these side effects on a patient's quality of life will need to be weighed, as well as the drug's as-yet-unknown effect on overall survival, said Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society.
"These [clinical trial] results are impressive as far as they go, meaning we don't know yet whether it improves the survival outlook for these patients," Lichtenfeld said. "We don't know if it's going to help people live longer, and given side effects we don't know if it will help them live better."
According to the American Cancer Society, about 62,450 new cases of thyroid cancer -- about three quarters of them in women -- will be diagnosed in the United States this year. There will be an estimated 1,950 deaths from the disease.
Thyroid cancer is typically diagnosed at a younger age than most adult cancers, with nearly two out of three cases found in people younger than 55. About 2 percent of thyroid cancers occur in children and teens, the cancer society said.
For more on thyroid cancer, visit the American Cancer Society.