(By Balachander) Exelixis Inc.'s (NASDAQ: EXEL) new drug to treat a rare form of thyroid cancer has been approved by the U.S. Food and Drug Administration (FDA).
The health regulator gave clearance for Exelixis' Cometriq capsule, formerly known as cabozantinib, to treat medullary thyroid cancer (MTC) that has spread to other parts of the body.
"Prior to today's approval and the approval of Caprelsa in April 2011, patients with this rare and difficult to treat disease had limited therapeutic treatment options," the FDA said on Thursday.
In April 2011, the FDA cleared Caprelsa from AstraZeneca Plc (NYSE: AZN) to treat the same condition.
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The COMETRIQ approval is based on the results of EXAM, a randomized phase 3 clinical trial conducted in 330 patients with progressive, metastatic MTC, which met its primary efficacy endpoint of improving progression-free survival (PFS).
South San Francisco, California-based Exelixis' Cometriq extended PFS for patients in a late-stage study to 11.2 months versus four months for patients receiving a placebo, the FDA noted.
Results also showed that 27 percent of patients treated with Cometriq had reductions in tumor size lasting an average of nearly 15 months, while patients who received a placebo saw no reductions.
Cometriq also received orphan-product designation by the FDA because it is intended to treat a rare disease or condition.
According to the FDA, the most common side effects were diarrhea; inflammation or sores of the mouth; redness, pain, or swelling of the digits (hand-foot syndrome); weight loss, among others.
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MTC develops in cells in the thyroid gland that make a hormone called calcitonin, which helps maintain a healthy level of calcium in the blood. This type of cancer may occur spontaneously or in families with certain genetic mutations that result in one or more cancers of the endocrine system, including the thyroid gland.
The National Cancer Institute estimates that 56,460 Americans will be diagnosed with thyroid cancer and 1,780 will die from the disease in 2012. About 4 percent of thyroid cancers are medullary thyroid cancer, making it one of the rarer types of thyroid cancers.
Shares of EXEL plunged 7.73 percent to trade at $4.84 on Friday. Over the past year, the stock has been trading between $4.05 and $6.95.