Cell Therapeutics’ Xyotax shrinks tumors in phase I study

In the study, 21 patients were treated to evaluate the safety of the regimen and to determine the maximum tolerated dose of Xyotax (paclitaxel poliglumex) in combination with 50.4Gy concurrent radiation.

Of the 12 patients with loco-regional disease in whom tumor responses were evaluated, four patients (33%) achieved a complete response and seven patients (58%) achieved a partial response (defined as 50% or greater shrinkage of their tumor), for an overall objective response rate of 91%.

At the maximum tolerated dose of 70mg/m2/week given for six weeks, one patient had grade 3 esophagitis. There were no grade 3/4 toxicities at dose levels below 70mg/m2/week. At the 80mg/m2 dose level, three of four patients had dose-limiting toxicities including grade 3 esophagitis/gastritis (two patients), grade 3 dehydration (one patient), and grade 4 neutropenia (one patient). Except for the four patients who experienced dose-limiting toxicity, all patients completed the full six weeks of concurrent chemoradiation.

“The safety profile of Xyotax and its protocol-defined dose with standard course radiation coupled with its impressive anti-tumor activity provide clinical support for preclinical studies demonstrating its great potency as a radiosensitizer,” stated Jack Singer, chief medical officer of Cell Therapeutics. “A follow-on study in combination with cisplatin and radiation is currently in progress.”