The Food and Drug Administration has approved the use of vandetanib to treat adult patients with late-stage medullary thyroid cancer who are ineligible for surgery and who have disease that is growing or causing symptoms.
Medullary thyroid cancer represents about three to five percent of all thyroid cancer, with an estimated incidence in the United States of about 1,300 to 2,200 patients, according to an FDA news release.
Vandetanib, which is made by AstraZeneca but as yet has no brand name, targets medullary thyroid cancer's ability to grow and expand. This is the first drug approved for this cancer.
Vandetanib's safety and effectiveness were established in a single, randomized international study of 331 patients with late-stage disease. Patients were randomized to receive either vandetanib or placebo.
Patients who received vandetanib had a longer period of time without disease progression when compared with patients receiving placebo. Median progression-free survival was 16.4 months in the placebo arm and at least 22.6 months in the vandetanib arm. The news release notes that it is still too early to determine the median progression-free or overall survival.
"Vandetanib's approval underscores FDA's commitment to approving treatments for patients with rare and difficult to treat diseases," said Richard Pazdur, MD, Director of the FDA's Office of Oncology Drug Products.
Common side effects occurring from vandetanib use include diarrhea, rash, nausea, high blood pressure, headache, fatigue, decreased appetite, and abdominal pain. Serious side effects reported during the study resulted in five deaths in patients treated with vandetanib. Causes of death included breathing complications, heart failure, and sepsis.
Vandetanib was shown to affect the electrical activity of the heart, which in some cases can cause irregular heartbeats that could lead to death. The drug is being approved with a Risk Evaluation and Mitigation Strategy (REMS) to inform health care professionals about these serious heart-related risks. Only health care professionals and pharmacies certified through the vandetanib REMS program, a restricted distribution program, will be able to prescribe and dispense the drug. Patients will also receive an FDA-approved Medication Guide informing them of the potential risks.