Calydon Begins U.S. Clinical Trial of the First Tissue-Specific Viral Therapeutic for Prostate Cancer

Business Wire, Sept 2, 1998

BALTIMORE--(BW HealthWire)--Sept. 2, 1998--Cancer researchers began testing Monday of an experimental drug in men with advanced prostate cancer that has been engineered to selectively replicate in and kill human prostate cancer cells.

It is the first viral therapeutic that acts exclusively upon cells found in a specific tissue or organ. This therapeutic, CN706, was developed by Calydon, Inc., a Sunnyvale, CA-based drug discovery and development company.

The Phase I clinical trial has been designed to assess the safety of different dosages of CN706 in patients with advanced and recurring prostate cancer. Antitumor activity and time to disease progression will be measured as secondary endpoints of the study. The trial, which began patient recruitment in July 1998, will enroll up to 30 subjects and is being conducted under the direction of Jonathan W. Simons, M.D., of The Johns Hopkins Brady Urological Institute and The Johns Hopkins Oncology Center.

"The attractiveness of this potential therapeutic is that it has the promise of addressing a major shortcoming of many cancer therapeutics today -- their non-selective toxic effects on healthy cells as well as toxic effects on cancer cells," said Dr. Simons. "We are looking forward to testing CN706 for prostate cancer, a disease which kills over 39,000 men in the U.S. each year."

Single Treatment Effective in Animal Trials

A common cold virus (adenovirus) has been engineered so that it grows only in human cancer cells in which prostate-specific antigen, or PSA, is present. PSA is the primary marker for prostate cancer and is used in diagnosis and management of prostate cancer. In experiments in mice with compromised immune systems, a single injection of CN706 reduced a one-gram tumor by an average rate of 84 percent. These findings were reported in Cancer Research, July 1997. At the same time, all treated animals were free of tumor and detectable serum PSA six weeks after treatment.

In laboratory tests, CN706 has demonstrated a therapeutic index of over 400:1, meaning that over 400 cancerous prostate cells were destroyed for each non-cancerous cell destroyed. By comparison, the therapeutic ratios of the traditional chemotherapy drugs are at best 6:1. Since Calydon's virus replicates in PSA expressing prostate cells, the therapeutic effect of a single dose is amplified as the virus replicates through the tumor.

Calydon, Inc., a privately held company, is engaged in the discovery and development of new viral therapeutics that target prostate and other cancers. The company is focused on the development of tissue-specific viruses that selectively infect and destroy cancer cells.

For information on participating in the trial, contact Johns Hopkins at 410/614-4234.

CONTACT: Calydon, Inc.

Christine Gray-Smith, 408/752-8752 (V.P., CFO)

info@calydon.com

http://www.calydon.com

or

Milestones

Lorraine Ruff, 206/214-0050 (Media)