Blood Vessel Drug May Treat Advanced Thyroid Cancer

When thyroid cancer is advancing aggressively, metastasizes to other locations, and becomes resistant to the usual treatment of radioiodine, the treatment options can become limited because traditional chemotherapy only works in less than 25% of these patients. Now, researchers are reporting that a new drug, motesanib diphosphate, is showing positive results in clinical trials, and may be effective in patients with metastatic thyroid cancer.

In a phase 2 study, 93 patients with advanced or metastatic, radioiodine-resistant thyroid cancer -- 57 (61%) had papillary thyroid carcinoma -- were treated with motesanib diphosphate. Of the 93 patients, almost half -- 49 percent -- had a positive response to motesanib diphosphate -- with tumors shrinking in 14 percent, and tumors stabilizing for more than 24 weeks in 35 percent of the test participants.

Another interesting finding was that some patients had had a particular genetic mutation responded better to the drug than those without the mutation.

The researchers concluded that motesanib diphosphate may be an effective treatment and induce at least partial response in some patients who have progressive, metastatic, radioiodine-resistant differentiated thyroid cancer. They do make it clear, however, that more studies should be conducted to further evaluate the treatment.

_{Reference: Sherman, SI, et. al. "Motesanib diphosphate in progressive differentiated thyroid cancer." N Engl J Med. 2008 Jul 3;359(1):31-42. Online}

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