Cell Therapeutics' Unique Orally Available, Multi-Kinase (JAK2, FLT3, c-Fms) Inhibitor CT-1578 Demonstrates Ability to Prevent the Onset of Rheumatoid Arthritis and Potency in Treating and Reversing Bone and Cartilage Damage In Preclinical Models

Results Reported in the Journal of Immunology

Oct 15, 2012, 01:30 ET from Cell Therapeutics, Inc.

SEATTLE, Oct. 15, 2012 /PRNewswire/ -- Cell Therapeutics, Inc. ("CTI") (Nasdaq and MTA: CTIC) announced today that CT-1578's (previously known as SB-1578) unique kinase spectrum that selectively inhibits JAK2 over JAK1 or JAK3, coupled with its inhibition of FLT-3 and c-Fms, produced potency in not only preventing the development of rheumatoid arthritis ("RA"), but also in its treatment and reversal of bone and joint destruction after the onset of RA in preclinical models according to results published in the October 15, 2012 issue of the Journal of Immunology.

The authors concluded that CT-1578's selective inhibition of JAK2, FLT-3 and c-Fms, which are the three kinases that are critical to the pathogenesis of RA, is unprecedented in the current stable of kinase inhibitors.

"These results support the hypothesis that inhibition of JAK1 and JAK3 is not mandatory for therapeutic benefit in RA," noted Jack W. Singer, M.D., EVP Global Medical Affairs and Translational Medicine at CTI. "The results demonstrate that CT-1578's unique kinase spectrum not only blocks the inflammatory response, but prevents the infiltration of macrophages and neutrophils into affected joints, while inhibiting antigen presenting dendritic cells and the autoimmune component of the disease. These attributes resulted in prevention of joint synovial hyperplasia and bone destruction, that was sufficiently impressive that the Journal of Immunology chose to use images of the results on the cover of the October 15th issue."

About the Study

In the study, when SB1578 was orally administered in a preclinical model of RA, it demonstrated a reduction of the level of proinflammatory cytokines, which was accompanied by a reduction in joint inflammation. In RA patients, the increase in cytokines correlates with disease progression and joint destruction. In the preclinical model, SB1578 was also effective in reversing an elevation in neutrophils, which play an essential role in the initiation of joint inflammation and damage to bone and cartilage resulting in a mitigation of damage to the joints. Additionally, SB1578 showed the ability to modulate the autoimmune component of RA that is involved in the early development of RA by inhibiting a pathway that leads to the initiation of an inflammatory response. The authors state, "The activities against these three kinases [JAK2, FLT-3 and c-Fms], which play crucial roles in the pathogenesis of arthritis, differentiates SB1578 from other less selective JAK family kinase inhibitors that are in clinical development for rheumatoid arthritis and provides a novel and attractive therapeutic alternative."

The publication by Madan, et al. titled "SB1578, a Novel Inhibitor of JAK2, FLT3, and c-Fms for the Treatment of Rheumatoid Arthritis," is available at http://www.jimmunol.org/.

About Janus Associated Kinase (JAK)

The JAK family of enzymes are a central component in signal transduction pathways, which are critical to normal blood cell growth and development as well as inflammatory cytokine expression and immune responses. When dysregulated by activating mutations, uncontrolled blood cell growth can occur accompanied by inflammation and immune system activation contributing to disease manifestations in myeloproliferative neoplasms.  Autoimmune diseases such as psoriasis and rheumatoid arthritis also have activation of this pathway.

About FLT-3

FLT-3 is a tyrosine kinase that is important for RA pathogenesis as FLT-3 mediated signaling is essential in the differentiation of dendritic cells leading to the to the amplification of systemic arthritogenic immune responses.  FLT-3 has also been shown to contribute to the bone erosion in arthritic joints.

About c-Fms

c-Fms is a tyrosine kinase receptor that is increased in several diseases that involve chronic activation of tissue macrophages, including RA. Elevate levels of its ligand M-CSF are observed in the joints of RA patients, contributing to the development of macrophages and osteoclasts, which are the mediators of bone erosion.  Inhibition of c-Fms has been shown to inhibit the progression of arthritis in preclinical models indicating that it may play a pivotal role in the pathogenesis of RA.

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.CellTherapeutics.com.

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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 and the market price of CTI's securities. Specifically, the risks and uncertainties that could affect the development of CT-1578 include risks associated with preclinical and clinical developments in the biopharmaceutical industry in general, and with CTI-1578 in particular, including, without limitation, the potential failure of CT-1578 to prove safe and effective for the treatment of patients with RA, either alone or in combination regimens, as determined by the U.S. Food and Drug Administration and/or the European Medicines Agency, that CT-1578 may not satisfy a medical need not currently addressed with existing non-selective or less selective JAK1/JAK2 inhibitors, that CT-1578 may not prevent the onset of RA and/or treat or reverse bone and cartilage damage from RA, that additional clinical trials of CT-1578 may not occur as planned, that the projected benefits of the acquisition of CT-1578 may not materialize as expected, that CTI may not be able to successfully implement its plans, strategies and objectives related to the acquisition and development of CT-1578, CTI's ability to continue to raise capital as needed to fund its operations, competitive factors, technological developments, costs of developing, producing and selling CTI's product candidates, 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, 10-Q and 8-K. Except as may be required by law, CTI does not intend to update or alter its forward-looking statements whether as a result of new information, future events, or otherwise.

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SOURCE Cell Therapeutics, Inc.