The News

Phase I/II Experience of Pixantrone CHOP-Variant (CPOP)

06/12/2004

Produces Responses in 70 Percent of Relapsed Aggressive
Non-Hodgkin’s Lymphoma Patients Who Previously Failed
CHOP Chemotherapy
Complete Responses Seen in 47 Percent of Patients

Dec. 6, 2004 San Diego—Preliminary results of a phase II study of a variant of the CHOP chemotherapy regimen which replaces doxorubicin with pixantrone in patients with relapsed aggressive non-Hodgkin's lymphoma (NHL) were presented at the 46th Annual Meeting of the American Society of Hematology (ASH). The phase II study of the pixantrone combination regimen, known as CPOP, produced impressive response rates including complete responses in 41 percent of the patients who had previously failed the standard CHOP chemotherapy and at least one additional multi-chemotherapy regimen. The treatment was effective and well tolerated. No patients experienced clinically significant cardiac toxicity despite most having previously received a high cumulative dose of doxorubicin, which can cause serious and irreversible heart damage. Cell Therapeutics, Inc. (CTI) (NASDAQ and Nuovo Mercato: CTIC) is also studying pixantrone in an ongoing phase III clinical trial in aggressive NHL.

The phase I/II experience with the CPOP regimen, in a total of 43 patients evaluable for response, produced a complete response in 20 patients (47 percent), with 10 patients (23 percent) experiencing a partial response and six patients (14 percent) achieving stable disease. This corresponds to a major objective response rate of 70 percent.

Medical Director of USC/Norris Cancer Hospital and a principle investigator on the phase III pivotal study of pixantrone, Alexandra Levine, M.D., commented on the CPOP data stating, "The data are quite impressive, particularly given that relapsed patients with the aggressive form of this disease rarely achieve a complete response. Moreover, the improvement in tolerability, particularly with respect to cardiac toxicity, represents an important advancement over the standard anthracycline-containing regimen. These data, along with the data observed in single-agent studies, prompted the initiation of the ongoing phase III trial of pixantrone, which was initiated in March of this year as well as a CPOP study in combination with Rituxan.”

About the CHOP Regimen
The CHOP chemotherapy regimen (a combination of cyclophosphamide, vincristine, prednisone and doxorubicin) is the standard-of-care treatment for newly diagnosed (front-line) aggressive NHL. Response rates following CHOP in front-line aggressive NHL can reach 70 percent and the regimen is potentially curative in up to 40 percent of patients. The prognosis is poor for patients who have a recurrence of the disease (relapsed patients). Despite its impressive antitumor activity, CHOP cannot be used to retreat the 60 to 65 percent of patients who will relapse following CHOP, due to the cumulative cardiotoxicity associated with one of its constituent agents, doxorubicin; a chemotherapy agent which belongs to the anthracycline family. The maximum lifetime recommended dose of doxorubicin ranges from 450mg to 550mg and this level is often reached during front-line treatment with CHOP.

About Pixantrone and the CPOP Regimen
Pixantrone is an investigational drug designed to potentially increase anti-tumor activity and decrease the potential for cardiac toxicity associated with the currently marketed anthracyclines. This trial examines the safety and potential efficacy of pixantrone when substituted for doxorubicin in the CHOP regimen among patients who have failed prior doxorubicin-containing CHOP therapy for aggressive NHL.

About Cell Therapeutics, Inc.
Headquartered in Seattle, CTI is a biopharmaceutical company committed to developing an integrated portfolio of oncology products aimed at making cancer more treatable.

This press release includes forward-looking statements that involve a number of risks and uncertainties, the outcome of which could materially and/or adversely affect actual future results. Specifically, the risks and uncertainties that could affect the development of CTI’s products under development include risks associated with preclinical and clinical developments in the biopharmaceutical industry in general and with CTI’s products under development in particular including, without limitation, the potential failure of pixantrone to prove safe and effective for treatment of aggressive NHL, determinations by regulatory, patent and administrative governmental authorities, competitive factors, technological developments, costs of developing, producing and selling pixantrone, 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 filings on Forms 10-K, 8-K, and 10-Q. CTI is under no obligation to (and expressly disclaims any such obligation to) update or alter its forward-looking statements whether as a result of new information, future events, or otherwise.

Investors
Cell Therapeutics, Inc.
Leah Grant
T: 206.282.7100 F: 206.272.4434
E: invest@ctiseattle.com
www.cticseattle.com/investors.htm

Media
Cell Therapeutics, Inc.
Kate Whitman
T: 206.272.4349 F: 206.272.4434
E: media@ctiseattle.com
www.cticseattle.com/media.htm