New Drug Slows Thyroid Cancer (HealthDay)

WEDNESDAY, July 2 (HealthDay News) -- An experimental drug thatinhibits tumor blood vessel formation slows the progression of metastaticthyroid cancer in some patients, an international study finds.

Of the 93 patients with rapidly progressing cancer, 49 had a positiveresponse to treatment with motesanib diphosphate. Of those 49 patients, 14percent had their tumors shrink and 35 had their tumors stabilize for morethan 24 weeks. Median progression-free survival was about 40 weeks.

Genetic analysis of 25 patients revealed that drug response was betterin those with a mutation known as BRAF V600E in their tumors than in thosewithout the mutation. Further research into this genetic connection isneeded, the researchers said.

"Finding that patients whose tumors bear a particular mutation weremore likely to respond to the drug is an example of where we would like tohead in our research," study author Dr. Steven I. Sherman, chairman andprofessor of the department of endocrine neoplasia and hormonal disordersat the University of Texas M.D. Anderson Cancer Center, said in a preparedstatement.

"This is the first of the various thyroid cancer trials to identifyspecific mutations that might allow us to individualize or personalizetherapy," he said.

The study, published in the July 3 issue of the New England Journalof Medicine, was funded by drug maker Amgen Inc.

Motesanib diphosphate -- a VEGF inhibitor -- targets a protein calledvascular endothelial growth factor (VEGF), which plays a critical role inthe formation of new blood vessels that allow tumors to grow andspread.

Currently, there are few treatment options for metastatic thyroidcancer.

"There is no standard accepted chemotherapy for advanced metastaticdifferentiated thyroid cancer, and response rates have typically been 25percent or less," Sherman said. "Most patients are not treated withsystemic chemotherapy, because the limited benefit rarely justifies theside effects. Treatment of thyroid cancer has been a completely unmetneed."

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