New data shows promising results for enhanced chemo

CHICAGO – (CancerDigest) – Cell Therapeutics, Inc (CTI) announced updated clinical trial data for its lead enhanced chemotherapy drug OPAXIO(TM) showing  15 of 40 patients (38%) with advanced esophageal cancer achieved a  complete response when treated with the drug in combination with cisplatin and radiation. A complete response is usually defined as no sign of the cancer in tissues examined under a microscope for 4 weeks or more.
The drug uses a novel approach to increase the effectiveness of paclitaxel. It uses a biodegradeable polymer to bind with paclitaxel. The resulting large molecule is too big to be absorbed into health tissues served by normal blood vessels. Cancerous tumors, however, are often served by more porous blood vessels that have large gaps in the vessel walls that allow the OPAXIO to pass through the blood vessel wall into the tumor. There the toxic paclitaxel is released to bind to structures, called spindles, within the nucleus that are only present when the cell is dividing. The result is that the self-destruction mechanism, called apoptosis, is triggered, causing the cell to die.

The goal is to get the paclitaxel to be preferentially taken in by tumor cells, causing cell death, while normal tissues are blocked from taking in the drug resulting in less toxic side effects from the drug. The technology could be applied to treatments for a number of cancers that currently are treated with paclitaxel or similar cell-killing chemotherapy agents.

CTI presented the new data at the annual meeting of the American Society of Clinical Oncolgists (ASCO) being held in Chicago this week by the study's lead investigator, Dr. Kimberly Perez, of the Warren Alpert School of Medicine, Brown University.

"OPAXIO significantly improved the pathologic complete response rate that has been shown in previous phase III trials using standard chemotherapy plus radiation," Perez said in a prepared statement. "Importantly, we did not see the severe regional side effects associated in treating patients with platinum, 5-FU, and radiation based regimens with only one patient requiring a feeding tube in this study. Typical rates of grade 3-4 esophagitis for this regimen are on the order of 40%."

CTI plans to meet with the FDA in the second half of 2010 to investigate the feasibility of designing a larger phase III trial to compare the effectiveness of OPAXIO regimens with current treatments.

SOURCE: adapted from press materials provided by Cell Therapeutics, Inc.