Motesanib can stabilize some advanced thyroid cancers

NEW YORK (Reuters Health) - Motesanib, a highly selective inhibitor of receptors for vascular endothelial growth factor, as well as those for other factors, appears to help maintain stable disease in many patients with advanced medullary thyroid cancer, researchers report in the June 29th online issue of the Journal of Clinical Oncology.

Dr. Martin J. Schlumberger of Institut Gustave Roussy, Villejuif, France, and colleagues conducted a phase II study of 91 patients with locally advanced or metastatic, progressive or symptomatic disease. They were given motesanib 125 mg per day orally for up to 48 weeks in the absence of unacceptable toxicity or disease progression.

Only 2 of the patients (2%) achieved an objective response. However, 81% had stable disease, including 48% who had durable stable disease lasting for 24 weeks or more and 76% who experienced a decrease from baseline in target lesion size.

Median progression-free survival was 48 weeks and ranged from 43 to 56 weeks. Among the most common treatment-related adverse events were diarrhea (41%), fatigue (41%) and hypothyroidism (29%).

Although most patients' disease stabilized, the overall observed response rate was poor, they conclude. However, the rates for stable disease "are encouraging" say the investigators.

"Improved results with motesanib may be achieved by adjusting the daily dose."

In comments to Reuters Health, Dr. Schlumberger added that "several oral compounds are effective in patients with metastatic disease from either medullary or differentiated thyroid cancer. Patients with these diseases should be encouraged to participate in clinical trials."

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