Former Immunex Management Team Chosen to Head-Up CTI Subsidiary Aequus BioPharma, Inc.

SEATTLE, May 14 /PRNewswire-FirstCall/ — Cell Therapeutics, Inc. (CTI) (Nasdaq; MTAX: CTIC) today announced the management team for its recently- formed subsidiary Aequus BioPharma, Inc. Carl J. March, Ph.D., MBA, a former Senior Vice President at Immunex has been chosen to lead the new company as President and CEO. Stewart D. Chipman, Ph.D., Vice President of Research at CTI and former Director of Biomolecular Screening at Immunex, who was a co- inventor of the technology and managed the team that advanced its development through an initial proof of concept stage, will serve as Executive Vice President and Chief Scientific Officer. David Cosman, Ph.D., former Distinguished Fellow and Research Director at Amgen and Vice President of Molecular Biology at Immunex, will join the Company’s Board of Directors.

CTI also announced it will co-develop AQB-101 with Aequus BioPharma, Inc. AQB-101 is being developed as a follow-on biologic that is a Genetic Polymer modified version of G-CSF, to help fight infection in some patients taking chemotherapy. The therapy has the potential to be dosed once per chemotherapy cycle similar to some currently marketed G-CSF products, such as Neulasta(R). Using Aequus’ Genetic Polymer technology to create the novel human therapeutic AQB-101 may result in greater ease of manufacture and a lower cost of goods.

“There is a lot of buzz around the Seattle venture and biotech community about this technology and its potential to rapidly develop follow-on biologics to current G-CSF or Interferon based human therapeutics while at the same time having novel applications for delivering small inhibitors of RNA,” said James A. Bianco, M.D., President and CEO of CTI. “We have put together some of the scientists from the team who participated in the development of biologics at Immunex, such as Leukine(R) and Enbrel(R), so we are confident we have the requisite experience in protein therapeutic development and manufacturing.”

CTI announced the formation of Aequus BioPharma in February. Its mission is to further develop the Genetic Polymer technology, discovered at CTI, which may speed the manufacture, development and commercialization of novel biopharmaceuticals including follow-on biologics or so-called biosimilars. CTI has committed to fund Aequus with a loan of up to $2 million and will initially retain a 70 percent equity interest in the new company.

“A key pitfall of protein therapeutics has been the relatively short plasma life of these types of drugs, which leads to the need for frequent injections and higher associated costs for therapies,” said Bianco. “Aequus BioPharma will utilize the Genetic Polymer technology which we expect to extend the plasma half-life of therapeutic proteins and provide a potentially less expensive, streamlined development pathway for next generation of biologics. Aequus’ technology can help speed access to the benefit of these new biotech drugs for millions of patients.”

Carl March spent over 19 years in R&D at Immunex, most recently serving as Senior Vice President of Information Technology and Biochemical Sciences. In addition to co-managing the day-to-day discovery research effort at Immunex, March was directly responsible for the company’s biochemical sciences group, which provided biochemistry, bioinformatics, protein chemistry, proteomics, and small molecule expertise to Immunex’s cytokine biology research platform. March was also responsible for the corporate library and information technology at Immunex and helped guide the successful integration of the company’s information systems with those at Amgen following its acquisition of Immunex in 2002. March received his Ph.D. in Chemistry from Purdue University and his MBA from the University of Washington Business School. He has served on numerous advisory boards and currently is a member of the Founding Board at the Information School (iSchool) at the University of Washington.

“I am very excited to team up with my former Immunex colleagues to help commercialize the very promising Genetic Polymer technology developed by Stewart and his team at CTI,” said March. “While our initial focus will be directed toward follow-on biologics, we certainly believe CTI’s discovery provides a platform which enables the rapid development of novel biotherapeutics so that patients can more readily benefit from the extreme pace of biomedical research we’re experiencing in the post-genome era.”

Stewart Chipman is a biotech executive with over 15 years of experience in building and leading scientific teams focused on the discovery and development of novel human therapeutics in the fields of inflammation, metabolic bone diseases, and cancer biology. Prior to joining Immunex, he was Director of Biology at ArQule in Boston. Chipman received his B.S. in Biology at Boston University and Ph.D. in Biochemistry from the Boston University School of Medicine. Prior to pursuing his career in biotech, he was an Associate Professor of Medicine at The Johns Hopkins University Medical School. He has co-authored more than 40 peer-reviewed scientific papers and is a co-inventor on seven U.S. and foreign patents.

David Cosman was educated at Cambridge University, then pursued his Ph.D. at Pennsylvania State University College of Medicine and Tufts University School of Medicine. He has published more than 130 peer-reviewed scientific papers and reviews and is a co-inventor on 35 U.S. patents as well as numerous foreign patents. One of the Institute for Scientific Information’s most highly-cited scientists in Immunology, he has served on the Scientific Advisory Boards of the Keystone Symposia and Amgen Ventures, and presently serves on the Scientific Advisory Board of another Seattle startup with Immunex roots, VLST Corporation.

Additional board members will include Jack W. Singer, M.D., CTI’s Chief Medical Officer and co-inventor of the Genetic Polymer technology, Fred W. Telling, Ph.D., CTI board member and former Vice President of Corporate Policy and Strategic Management for Pfizer Inc., as well as Dr. Bianco, who will serve as non-executive Chairman.

About Biologics

Biologics, especially recombinant DNA (rDNA) derived protein biopharmaceuticals, represent the fastest growing segment of pharmaceutical sales, currently at $51 billion worldwide and expected to hit $87 billion by 2010. Industrial scale protein production technologies are currently being applied to the development of a wide variety of protein-based therapeutics, including hormones, growth factors, antibodies and cytokine modulators, to treat a vast range of human diseases. But these drugs have a relatively short plasma half life. As a result, several physical, genetic and chemical approaches have been developed to extend the plasma half life of the therapeutic proteins while not compromising efficacy or introducing safety issues (immunogenicity and other off-mechanism toxicities). The most successful of these approaches has been chemical conjugation with monomethoxypolyethylene glycol (PEG), amino acid engineering leading to altered protein glycosylation and the addition of non-biologically active “carrier” domains.

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 http://www.cticseattle.com/.

About Aequus BioPharma, Inc.

Headquartered in Seattle, Aequus BioPharma is a biopharmaceutical company committed to developing affordable and improved biopharmaceuticals in a wide variety of human disease indications. For additional information, please visit http://www.aequusbiopharma.com/.

This press release includes forward-looking statements about the formation of Aequus BioPharma, the Genetic Polymer(TM) technology developed by CTI and the co-development of AQB-101 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 transaction include risks associated with Aequus BioPharma’s unproven technology, preclinical and clinical developments in the biopharmaceutical industry in general and with the Genetic Polymer technology in particular including, without limitation, further research and development of AQB-101, the ability of Aequus BioPharma to raise additional capital as needed to fund its development programs, and the risk factors listed or described from time to time in CTI’s filings with the Securities and Exchange Commission including, without limitation, CTI’s most recent filings on Forms 10-K, 8-K, and 10-Q. Except as may be required by Italian law, CTI does not intend to update or alter its forward-looking statements whether as a result of new information, future events, or otherwise.

   Media Contact:   Cell Therapeutics, Inc.   Dan Eramian   T: 206.272.4343   C: 206.854.1200   Susan Callahan   T: 206.272.4472   F: 206.272.4434   E: [email protected]   http://www.cticseattle.com/media.htm    Investors Contact:   Cell Therapeutics, Inc.   Leah Grant   T: 206.282.7100   F: 206.272.4434   E: [email protected]   http://www.cticseattle.com/investors.htm   Aequus BioPharma, Inc.   Carl J. March   T:  (206) 855-7802   Email:  [email protected]  

Cell Therapeutics, Inc.

CONTACT: media, Dan Eramian, +1-206-272-4343, cell, +1-206-854-1200, orSusan Callahan, +1-206-272-4472, fax, +1-206-272-4434, [email protected],or investors, Leah Grant, +1-206-282-7100, fax, +1-206-272-4434,[email protected], all of Cell Therapeutics, Inc.; or Carl J. March ofAequus BioPharma, Inc., +1-206-855-7802, [email protected]

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

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