Cell Therapeutics, Inc. Release: Pixantrone Combination Regimen Produces High Rates Of Complete Remission For Patients With Aggressive NHL Who Fail CHOP Therapy

SEATTLE, March 22 /PRNewswire-FirstCall/ -- At the 2006 Invest Northwest conference, Cell Therapeutics, Inc. (CTI) presented preliminary results of a phase I/II clinical trial of pixantrone in 64 patients with relapsed aggressive non-Hodgkin's lymphoma who had previously failed one or two prior chemotherapy regimens, including the CHOP regimen. The two-part study was designed to determine the maximum tolerated dose and evaluate the drug's effectiveness in a combination known as CPOP, in which pixantrone replaces doxorubicin in the standard CHOP regimen. All patients on the study had received prior doxorubicin therapy and as such were at risk for developing severe cardiac toxicity with additional anthracycline therapy.

The CPOP regimen was highly effective, with complete response/unconfirmed complete response rates of 41 percent (14 of 34 patients) and 43 percent (13 of 30 patients) and overall response rates of 71 percent (24 of 34 patients) and 77 percent (23 of 30 patients) in the phase 1 and 2 component of the study, respectively. Predominant side effects were blood-related and included 60 to 75 percent grade 4 neutropenia and 23 percent febrile neutropenia. Grade 3 infections were observed at the 150 mg/m2 dose level (10 percent), but no grade 3 infections have been reported to date at the 180 mg/m2 dose level. There was one case of congestive heart failure reported, which was felt by the investigator to be related to the patient's underlying cardiac disease.

"These data suggest that in the relapsed setting, substituting pixantrone for doxorubicin can offer patients a high probability of achieving a complete remission not available with standard chemotherapy regimens and underscores the rationale for studying the CPOP regimen versus the CHOP regimen in first-line treatment of aggressive NHL," stated James A. Bianco, M.D., President and CEO of CTI. "Complete responses are the reference standard in treating non-Hodgkin's lymphoma, since it not only correlates with longer survival, but among patients who are at high risk for disease recurrence, a CR is required in order for them to undergo potentially curative bone marrow transplants."

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 (first-line) aggressive NHL. Response rates following CHOP in first-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 anti-tumor 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 450 mg to 550 mg and this level is often reached during first-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. The CPOP regimen includes pixantrone, cyclosphosphamide, vincristine, and prednisone. Patients were treated with escalating doses of pixantrone, starting at a dose of 80 mg up to 180 mg/m2.

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. For additional information, please visit www.cticseattle.com. 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 pixantrone include risks associated with preclinical and clinical developments in the biopharmaceutical industry in general and with pixantrone 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.

CONTACT: investors, Leah Grant, +1-206-282-7100, or fax, +1-206-272-4434,or invest@ctiseattle.com, or media, Susan Callahan, +1-206-272-4472, orfax, +1-206-272-4434, or media@ctiseattle.com, both of Cell Therapeutics,Inc.

Web site: http://www.cticseattle.com/