FDA Approves Vandetanib for Medullary Thyroid Cancer
Earlier this week, the U.S. Food and Drug Administration (FDA) approved vandetanib for the treatment of medullary thyroid cancer.
Only adult patients with late-stage (metastatic) medullary thyroid cancer who are ineligible for surgery and who have disease that is growing or causing symptoms will be eligible for use of vandetanib.
According to the National Cancer Institute, thyroid cancer represents approximately 2% of malignancies occurring in the United States. There are an estimated 44,670 new thyroid cancer diagnoses each year and 1,690 deaths per year due to thyroid cancer. Only 2% to 3% of these thyroid cancers are medullary thyroid cancer (MTC), making it one of the rarer forms of thyroid cancer.
Thyroid cancer is a cancerous growth of the thyroid gland, which is located in the neck. MTC arises from the parafollicular calcitonin-secreting cells of the thyroid gland. MTC occurs in two forms: sporadic or spontaneous and familial or hereditary (genetic) forms. and may be preceded by C-cell hyperplasia (CCH), though CCH is a relatively common abnormality in middle aged adults.
Common symptoms of medullary thyroid cancer may include coughing, difficulty swallowing, enlargement of the thyroid gland, swelling of the neck, a lump on the thyroid, and changes in a person’s voice or hoarseness.
Prior to the approval of Vandetanib, there were no FDA-approved drug treatments for MTC. Vandetanib targets medullary thyroid cancer’s ability to grow and expand and is administered orally on a daily basis.
Vandetanib’s safety and effectiveness were established in a single, randomized international study of 331 patients with late-stage medullary thyroid cancer. Patients in the study were selected to receive vandetanib or placebo (sugar pill).
The study was designed to measure the length of time a patient lived without the individual’s cancer progressing (progression-free survival). Patients who received vandetanib had a longer period of time without disease progression when compared to 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. 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.
“Vandetanib’s approval underscores FDA’s commitment to approving treatments for patients with rare and difficult to treat diseases,” said Richard Pazdur, M.D., director of the Office of Oncology Drug Products in the FDA’s Center for Drug Evaluation and Research.
Common side effects occurring from vandetanib use include diarrhea, rash, nausea, high blood pressure, headache, fatigue, decreased appetite, and stomach (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 a bacterial infection in the blood (sepsis).
Vandetanib was shown to affect the electrical activity of the heart, which in some cases can cause irregular heart beats that could lead to death. Vandetanib 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.
Vandetanib is marketed by AstraZeneca Pharmaceuticals LP of Wilmington, Del. There is no trade name established for this drug at this time.