['Anaplastic thyroid cancer (ATC) is extremely aggressive, and no effective treatment is available. Combretastatin A4 phosphate (CA4P), a vascular disrupting agent, has limited activity against ATC in a clinical trial, and so does paclitaxel.', 'We hypothesized that a triple-drug combination including CA4P and paclitaxel would improve efficacy against ATC. Therefore, we evaluated two such combinations in vivo.', 'We used a nude mouse xenograft model with ARO and KAT-4 cells.', 'The first combination consisted of CA4P, paclitaxel, and manumycin A (a farnesyltransferase inhibitor), and the second, CA4P, paclitaxel, and carboplatin.', 'Main outcome measures included tumor growth curves and tumor weights.', "Tumor growth curve analysis (linear mixed models, P < 0.05) and xenograft weight analysis (Kruskal-Wallis one-way ANOVA on ranks, post hoc pairwise comparison, Dunn's test, P < 0.05) demonstrated that both triple-drug combinations were significantly better than placebo for both cell lines. Anti-bromodeoxyuridine immunostaining of xenograft sections from animals injected with bromodeoxyuridine before being killed showed that CA4P alone did not inhibit DNA synthesis, but manumycin A and paclitaxel did. CA4P decreased the depth of the viable outer rim of tumor cells on xenograft sections. Using electron microscopy, we found blebbing/budding of endothelial cells into capillary lumens and autophagy of tumor cells in CA4P-treated xenografts."] Is combination chemotherapy including combretastatin A4 phosphate and paclitaxel effective against anaplastic thyroid cancer in a nude mouse xenograft model?