CELATOR PHARMACEUTICALS PRESENTS POSITIVE RESULTS FROM PHASE I STUDY FOR CPX-1 AT AMERICAN SOCIETY FOR CLINICAL ONCOLOGY MEETING

Company will initiate Phase 2 studies with CPX-1 in metastatic colorectal cancer and announces plans for a Phase 1 study for CPX-351, second compound based on Celator's proprietary CombiPlex™ technology.

PRINCETON, NJ (June 5, 2006) – Celator Pharmaceuticals announced positive results from a Phase 1 study for CPX-1, the company's lead compound in development as a potential therapy for patients with colorectal cancer. Results of the Phase 1 study were presented in a poster presentation at the American Society for Clinical Oncology (ASCO) meeting in Atlanta.

CPX-1, a fixed-ratio formulation of irinotecan and floxuridine, was developed using Celator's proprietary CombiPlex™ technology designed to produce combination chemotherapies that are able to maintain synergistic drug ratios when administered systemically. In the Phase 1 study, 26 patients with advanced solid tumors were treated with escalating doses of CPX-1. Based on the results of the Phase 1 study, Celator will initiate a Phase II study with CPX-1 in patients with colorectal cancer during the third quarter of 2006.

"We continue to see great potential in using CombiPlex technology to improve the effectiveness of combination chemotherapy for treating different forms of cancer. Among 26 extensively pretreated patients in the CPX-1 study, 23 were evaluable, 15 had stable disease, and two showed partial clinical responses. These results are very encouraging in a Phase I trial," said Arthur Louie, M.D., Celator's medical director.

The company also announced that the FDA has approved an IND application for CPX-351, the second combination chemotherapy based on Celator's CombiPlex technology. CPX-351 is a synergistic fixed ratio combination of cytarabine and danorubicin in development as a potential treatment for acute myeloid leukemia. The company plans to initiate a Phase 1 study for CPX-351 in late 2006.

"These are important milestones for Celator and for our CombiPlex technology platform. We are very pleased by the Phase 1 results for CPX-1, and look forward to advancing this promising product candidate into Phase 2 studies and initiating a Phase 1 study for CPX-351 this year," said Dr. Andrew Janoff, chairman and chief executive officer of Celator.

Celator's CombiPlex Technology Platform

Many forms of cancer are currently treated with combinations of individual chemotherapy agents. In developing these drug combinations, clinicians typically combine agents that have non-overlapping toxicities and use each agent at its maximum tolerated dose. This makes it possible to combine different agents at their individual maximum tolerated doses. While this approach has represented the standard of care in oncology for many years, it may produce less than optimal treatment outcomes because it fails to recognize the critical role that drug ratios can play in combination chemotherapies.

Celator's proprietary CombiPlex technology platform has shown significant success in identifying and "locking in" the optimal drug ratios for combination chemotherapies. With this technology advantage, Celator is positioned to develop an expansive pipeline of new combination chemotherapies able to target cancer with enhanced efficacy.