Phase I study of CBT-1 and Taxol in patients with Taxol resistant cancers.

CBT-1, a natural product, was studied as an MDR modulator with Taxol (135 mg/m2) in an escalating dose Phase I clinical trial. CBT-1 was administered orally at doses from 300 mg/m2 to 500 mg/m2 daily x 7. The MTD was determined to be 500 mg/m2 with moderate nausea and occasional emesis. Side effects were mainly attributable to Taxol rather than the study drug. A total of 18 patients were registered on study with only one patient determined to be intolerant of CBT-1 due to nausea and emesis. In this Phase I study four patients (3 breast, 1 NSCLC) remained stable for greater than two cycles of treatment. No complete or partial responses were seen in this Taxol resistant population of patients with advanced cancer.