The Food and Drug Administration on April 6 approved vandetanib for the treatment of metastatic medullary thyroid cancer in adults – making it the first drug approved for this rare cancer.
Vandetanib is indicated for adults with metastatic medullary thyroid cancer, "who are ineligible for surgery and who have disease that is growing or causing symptoms," the agency said. It is administered orally once a day.
Approval was based on an international phase III study that compared treatment with oral vandetanib, 300 mg once a day, with placebo in 331 patients with unresectable locally advanced or metastatic medically thyroid cancer. The risk of progression with vandetanib was reduced by 54%, compared with placebo, a significant effect.
Among those on placebo, median progression-free survival was 16.4 months, compared with at least 22.6 months among those on vandetanib, according to the FDA statement, which added: "It is too early to determine the median progression-free survival in patients treated with vandetanib or to tell whether they will live longer (overall survival) compared to patients treated with placebo." Diarrhea, rash, nausea, high blood pressure, headache, fatigue, decreased appetite, and abdominal pain were among the adverse effects associated with treatment. In the study, serious adverse events resulted in five deaths in patients treated with vandetanib, according to the FDA; causes included breathing complications, heart failure, and sepsis.
Because vandetanib can cause QT interval prolongation, it is being approved with a Risk Evaluation and Mitigation Strategy (REMS) to inform health care professionals about cardiac risks and will be available through a restricted distribution program, so that only health care professionals and pharmacies certified through the vandetanib REMS program will be able to prescribe and dispense the product. Patients also will be given a medication guide that explains the risks of treatment.
An estimated 3%-5% of all thyroid cancers are medullary thyroid cancer, and the incidence of this cancer in the United States in 2010 was about 1,300-2,200 patients, according to the FDA.
There is no trade name yet for the drug, manufactured by AstraZeneca Pharmaceuticals.