Treatment with OPAXIO® (Paclitaxel Poliglumex),Temozolomide and Radiotherapy Results in Encouraging Progression Free Survival in Patients With High Grade Malignant Brain Tumors

CHICAGO, June 6, 2011 /PRNewswire/ -- Cell Therapeutics, Inc. ("CTI") (NASDAQ: CTICD and MTA: CTIC) announced encouraging interim results of a phase II clinical study of  OPAXIO (paclitaxel poliglumex, PPX) combined with temozolomide ("TMZ") and radiotherapy ("RT") in patients with newly diagnosed high-grade malignant brain tumors (astrocytomas and glioblastomas). While not a randomized trial, treatment with OPAXIO, TMZ and RT resulted in a median progression free survival (PFS) of 13.5 months. Median overall survival ("OS") has not yet been reached with a median follow-up of 22 months. The study was presented by Drs. Suriya Jeyapalan, Heinrich Elinzano and Mark Goldman, Assistant Professors of Neurology and Neurosurgery, Brown University Oncology Group at the 2011 American Society of Clinical Oncology Annual Meeting.  

OPAXIO is a potent radiosensitizer that increased the curability rate of cancers in preclinical models without increasing toxicity to normal tissues (Int. J. Rad. Oncol. Biol. Phys., 55:707-712, 2003).  The present study was performed to determine the safety and efficacy of   OPAXIO when it was added to standard therapy with radiation and temozolomide for unresectable high grade brain tumors (anaplastic astrocytomas (AA) and glioblastoma multiforme (GBM)).

"The data from the OPAXIO study is provocative. With an overall survival not yet reached at a median follow-up of 22 months, the addition of OPAXIO to the treatment of GBM could represent a major advance in prolonging survival in this otherwise rapidly fatal disease," commented Howard Safran, M.D., Head of the Brown University Oncology Group. "We look forward to confirming these findings in a randomized controlled trial of OPAXIO plus RT compared to TMZ plus RT in patients who are known to have limited benefit from TMZ due to expression of a gene termed MGMT that adversely impacts the effectiveness of alkylating agents such as TMZ."

In the current study, 25 patients were enrolled with confirmed high-grade glioma, of which 17 patients (68%) had GBM and 8 patients (32%) had AA.  Patients received OPAXIO with TMZ and RT for six weeks.  The main toxicity reported was grade 4 thrombocytopenia and neutropenia (6 patients (24%)).  These toxicities were felt to be due to a potential drug interaction between OPAXIO and TMZ and/or and other concomitant medications. Among the 22 evaluable patients, the overall response rate was 45% (ten of 22) with 27% (six of 22) of patients achieving a complete response. With a median follow-up of 22 months, 76% of patients remained free from disease progression at 6 months with an overall median PFS of 14.9 months (13.5 months for patients with GBM).

The poster from the 2011 American Society of Clinical Oncology Annual Meeting is available at www.celltherapeutics.com/investor_updates.

About OPAXIO(TM)

OPAXIO(TM) (paclitaxel poliglumex, CT-2103), which was formerly known as XYOTAX(TM), is an investigational, biologically enhanced, chemotherapeutic that links paclitaxel, the active ingredient in Taxol®, to a biodegradable polyglutamate polymer, which results in a new chemical entity. When bound to the polymer, the chemotherapy is rendered inactive, potentially sparing normal tissue's exposure to high levels of unbound, active chemotherapy and its associated toxicities. Blood vessels in tumor tissue, unlike blood vessels in normal tissue, are porous to molecules like polyglutamate. Based on preclinical studies, it appears that OPAXIO is preferentially distributed to tumors due to their leaky blood vessels and trapped in the tumor bed allowing significantly more of the dose of chemotherapy to localize in the tumor than with standard paclitaxel. Once inside the tumor cell, enzymes metabolize the protein polymer, releasing the paclitaxel chemotherapy.

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.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 trading price of CTI's securities. Specifically, the risks and uncertainties that could affect the development of OPAXIO include risks associated with preclinical and clinical developments in the biopharmaceutical industry in general, and with OPAXIO in particular, including, without limitation, the potential failure of OPAXIO to prove safe and effective and/or less toxic and effective for the treatment of newly diagnosed high-grade malignant brain tumors such as AA and GBM, including when combined with TMZ and RT, the potential failure of OPAXIO when combined with TMZ and RT to provide PFS and OS responses to high-grade malignant brain tumors such as AA and GBM, that the Brown University Oncology Group may not be able to confirm the findings of the OPAXIO Study in a randomized controlled trial of OPAXIO plus RT compared to TMX and RT, and CTI's ability to continue to raise capital as needed to fund its operations, competitive factors, technological developments, costs of developing, producing and selling pixantrone, and the risk factors listed or described from time to time in CTI's filings with the U.S. 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.

Media Contact:
Dan Eramian
T: 206.272.4343
C: 206.854.1200
E: [email protected]
www.CellTherapeutics.com/press_room

Investors Contact:
Ed Bell
T: 206.282.7100
Lindsey Jesch Logan
T: 206.272.4347
F: 206.272.4434
E: [email protected]
www.CellTherapeutics.com/investors

Medical Information Contact:
T: 800.715.0944
E: [email protected]

SOURCE Cell Therapeutics, Inc.