Quintessence Biosciences: Cancer drug, QBI-139, clears FDA review to start Phase I human trial

MADISON, WISCONSIN— December 5, 2008 – Quintessence Biosciences, Inc. announced today that the U.S. Food and Drug Administration (FDA) has cleared its Investigational New Drug (IND) application for the first of the Company’s EVade™ Ribonuclease drug candidates, called QBI-139. The Company will begin a Phase I trial of QBI-139 in patients with solid tumors in the coming months.

Unlike conventional chemotherapies, the EVade™ Ribonuclease technology provides an opportunity to attack RNA in cancer cells, an exciting new drug target, with QBI-139, which is nearly identical to a human protein, pancreatic ribonuclease 1. In preclinical disease models, QBI-139 has shown significant tumor growth inhibition against human pancreatic, non-small cell lung, prostate, and ovarian solid tumors.

“Clearance of the IND application by the FDA represents the first major clinical development milestone for QBI-139,” said Quintessence Biosciences President Laura Strong. “We are optimistic that QBI-139 will provide a new means to help patients with cancer. There is a clear need for drugs that attack cancer in new ways and ribonuclease therapies are positioned to accomplish that goal.”

About Quintessence Biosciences, Inc.

Quintessence Biosciences, Inc. is a private biopharmaceutical company focused on development of proprietary cancer therapies based on the EVade™ Ribonuclease technology. Quintessence’s first product candidate, QBI- 139, is anticipated to enter a Phase 1 clinical trial in late 2008. The company also has a pipeline of other EVade™ Ribonuclease products in preclinical research. For more information, visit http://www.quintbio.com.

Laura E. Strong

Quintessence Biosciences, Inc.

505 S. Rosa Road

Madison, WI 53719

Phone: 608-441-2950

Fax: 608-441-2952

EMail: lauras@quintbio.com