Quintessence Biosciences: Presents on Phase I trial of human ribonuclease variant, QBI-139, at the American Society of Clinical Oncology Annual Meeting

Contact: Laura E. Strong, Quintessence Biosciences, Inc. 608-441-2950

MADISON, WI – Quintessence today announced that the ongoing Phase I trial for their lead EVade™ Ribonuclease, called QBI-139, will be presented at the American Society of Clinical Oncology Annual Meeting. QBI-139 represents an innovative therapeutic approach by targeting the RNA in cancer cells. The Trials in Progress abstract (TPS3113) is scheduled for 8 AM on Monday 4, 2012. The design of the first in human Phase I clinical trial of QBI-139 will be presented along with pre-clinical data. QBI-139 has shown broad single agent activity against a variety of cancer models addressing significant unmet need and the company recently presented pre-clinical data supporting combination therapy with QBI-139 against non-small cell lung and ovarian cancers. Completion of the Phase I trial is anticipated this year.

About Quintessence Biosciences, Inc.

Quintessence Biosciences, Inc. is a private, clinical stage biopharmaceutical company developing novel anti-cancer compounds based on the patented EVade™ Ribonuclease technology. The most advanced lead candidate, QBI-139 is in a Phase 1 clinical trial at The University of Texas M.D. Anderson Cancer Center and The University of Wisconsin Carbone Cancer Center. The company has additional EVade™ Ribonuclease products in earlier stages of development.

About the ASCO Annual Meeting Trials in Progress Poster Session

The objective of the Trials in Progress Poster Session is to publicize ongoing phase I or phase II trials and stimulate discussion and participation among peers. The posters discuss the science behind the trial, including pre-clinical data. In addition, the posters describe the trial design and current enrollment status.