Memorial Sloan-Kettering Scientists Present Patient Data On Cell Therapeutics' Novel Anti-cancer, Anti- Angiogenesis Drug Candidate At the Annual Meeting of the American Society of Clinical Oncology.

SEATTLE--(BW HealthWire)--May 18, 1998--Cell Therapeutics, Inc. (Nasdaq:CTIC) today announced that data from a Phase I clinical trial of CT-2584, its novel small-molecule, anti-cancer, anti-angiogenic drug under investigation for the treatment of chemotherapy-resistant (advanced and refractory) cancers was presented at the 34th Annual Meeting of the American Society of Clinical Oncology in Los Angeles.

The presentation, entitled "A Phase I Study of CT-2584 in the Treatment of Advanced Carcinoma" was made by Roger Waltzman, MD, lead author. David Spriggs, MD, is the senior author and Principal Investigator for the trial, which was conducted at the Memorial Sloan-Kettering Cancer Center (MSK) in New York City. The study was designed to establish a maximum tolerated dose, develop a pharmacokinetic profile and evaluate the anti-tumor effect of CT-2584. This study is a companion to one being conducted at Christie Hospital in Manchester England.

CT-2584 therapy is administered intravenously over six-hour infusions for three consecutive days, followed by 18 days where no CT-2584 is administered. This constitutes one cycle of therapy. If no dose limiting toxicities are observed during the first cycle, a second cycle of therapy is administered. Patients who have received two cycles are evaluable for anti-tumor response. Patients whose cancers have stopped progressing (stable disease) or have reduced tumor size, are eligible to receive up to a total of six cycles of CT-2584 therapy.

In the United States, 23 patients have been enrolled, 22 at MSK and one under a compassionate study using the MSK protocol described above. All 23 patients are evaluable for toxicities, with 18 evaluable for tumor response. To date, no dose-limiting side effects, such as severe nausea and vomiting, low blood counts or gastrointestinal damage have been observed. Of the 18 patients evaluable for tumor response, 13 remain alive at a median of eight months (range 2-19 months) out from treatment with CT-2584. Five patients (27%) experienced tumor stabilization.

Carolyn Paradise, MD, head of medical affairs, at Cell Therapeutics, stated: "We continue to be impressed with the activity of CT-2584 seen in these early trials and by the tolerability profile of the drug. Combined with patients enrolled in our CT-2584 trial in the United Kingdom, we have treated more than 50 patients, 35 of whom were evaluable for tumor response to CT-2584. It is exciting that 10 (29%) of these patients' cancers stabilized on CT-2584, and that seven are still alive after a median of 10 months following treatment. Overall survival for all 35 evaluable patients in both trials is also very encouraging with 21 alive a median of 10 months after starting treatment with CT-2584. With this tolerability profile, synergistic effects with certain standard chemotherapeutics and the possibility of oral administration, chronic longer-term outpatient therapy may be possible. This could be a major benefit for cancer patients."

According the James A. Bianco, MD, president and CEO of Cell Therapeutics, CT-2584 appears to be particularly promising in the treatment of patients with advanced prostate cancer and sarcomas. "We believe this to be attributable both to the direct tumor toxic effects of CT-2584 and to its potent anti-angiogenic effects," said Dr. Bianco. "Based on the results observed thus far, we plan to begin Phase II trials this year in both advanced prostate cancer and in advanced sarcomas."

Cell Therapeutics believes that CT-2584 has a unique mechanism of action of tumor-cell killing. This mechanism involves CT-2584's effect on tumor-cell phospholopids such as phosphatidic acid (PA), which is believed to play an active role in neoplastic cell transformation. In preclinical studies, CT-2584 was effective in vitro against a broad array of tumor cell types, including those resistant to multiple kinds of chemotherapy drugs at drug levels that were non-toxic to normal human bone marrow cells. In addition, CT-2584 significantly inhibited cancer cell-induced new blood vessel formation (angiogenesis) at drug levels below which cancer-cell killing was observed.

This news release includes forward-looking statements that involve a number of risks and uncertainties, the outcome of which could materially adversely affect actual future results. Specifically, the risks and uncertainties that could affect the development of lisofylline and related compounds includes risks associated with preclinical and clinical development in the biotechnology industry in general and of CT-2584 and related compounds in particular (including, without limitation, the potential failure of CT-2584 and related compounds to prove safe or effective for treatment of disease), determinations by regulatory, patent, and administrative governmental authorities, competitive factors, technological developments, costs of developing, producing, and selling CT-2584 and related compounds, and the risk factors listed or described from time to time in the Company's filings with the Securities and Exchange Commission including, without limitation, the Company's most recent Registrations on Forms 10-K, 8-K and 10-Q.

Cell Therapeutics, Inc. focuses on the discovery, development, and commercialization of small molecule drugs that selectively regulate the metabolism of oxidized lipids and phospholipids relevant to the treatment of cancer and inflammatory and immune diseases.

CONTACT: Cell Therapeutics, Inc.

Lee M. Parker, 800/664-CTIC

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