OPAXIO(TM) Phase II Study Results Confirm High Rate of Complete Response with Low Rate of Side Effects in Patients with Advanced Esophageal Cancer

CTI to explore Phase III study

Jun 07, 2010, 01:30 ET from Cell Therapeutics, Inc.

CHICAGO, June 7 /PRNewswire-FirstCall/ -- Cell Therapeutics, Inc. ("CTI") (Nasdaq and MTA: CTIC) announced today that updated phase II study results of OPAXIO (paclitaxel poliglumex) in patients with advanced esophageal cancer demonstrated that 38% (15/40) patients receiving OPAXIO in combination with cisplatin and concurrent radiation achieved a pathologic or endoscopic complete response.  A pathological complete response, observed in 32% of patients, is recorded only when the esophagus is surgically removed after therapy and no tumor can be found microscopically.  In historical studies, pathologic complete response has correlated with prolonged survival.  Pathologic complete response rates with the current U.S. standard regimen of 5FU + cisplatin chemotherapy with concurrent radiation for patients with esophageal cancer are approximately 15% with 40% of patients experiencing severe (grade 3-4) inflammation and ulcers in the esophagus and stomach necessitating tube feeding. The results were presented by Kimberly Perez, M.D., Warren Alpert School of Medicine, Brown University, at the American Society of Clinical Oncology Annual Meeting in Chicago, Illinois. CTI plans to meet with the U.S. Food and Drug Administration ("FDA") in the second half of 2010 to explore a potential phase III registration study based on these results.

"OPAXIO significantly improved the pathologic complete response rate that has been shown in previous phase III trials using standard chemotherapy plus radiation," said Dr. Perez. "Importantly, we did not see the severe regional side effects associated in treating patients with platinum, 5-FU, and radiation based regimens with only one patient requiring a feeding tube in this study. Typical rates of grade 3-4 esophagitis for this regimen are on the order of 40%."

The phase II study enrolled 40 patients with pathologically-confirmed, locally-advanced adenocarcinoma or squamous cell carcinoma of the esophagus or gastro-esophageal junction with no evidence of distant metastisis.  The patients received weekly paclitaxel poliglumex (50mg/m2) and cisplatin (25mg/m2) for six weeks with concurrent 50.5Gy of radiation. The updated data demonstrated that of the 37 patients who underwent surgery, 12 patients achieved a pathologic complete response.  Additionally, three patients achieved a complete clinical endoscopic response and refused surgery.  Importantly, only one patient required a feeding tube and one patient used total parenteral nutrition. There were no grade 4 hematologic adverse events. Grade 3 hematologic adverse events included neutropenia (6%) and grade 3 non-hematologic toxicities included nausea (8%), esophagitis (6%), allergy (6%) and fatigue (3%).

"The high pathologic complete response rate coupled with tolerability confirms the striking efficacy of OPAXIO as a tumor-specific radiosensitizer in preclinical studies (Milas et al.; Int J Radiation Oncol Biol. Biophys, 55:2-7-12, 2003) and the previous phase I study of OPAXIO and radiation in locally advanced esophageal and gastric cancer (Dipetrello et al.: American Journal of Clinical Oncology: 29:376-379, 2006)," said Jack Singer, M.D., Chief Medical Officer of CTI. "The important features of the current study are both the higher than historical pathological response rate, a potential excellent surrogate for long-term survival, and the dramatically lower side effects than would be expected from conventional neoadjuvant chemoradiotherapy with cisplatin and 5-FU."

The poster is available at http://www.celltherapeutics.com/investor_updates.


OPAXIO™ (paclitaxel poliglumex, CT-2103), which was formerly known as XYOTAX™, 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 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 for OPAXIO to be proved safe and effective (or to achieve response rates) for the treatment of the indications noted in this press release or any other indication, determinations by regulatory, patent and administrative governmental authorities, the potential that OPAXIO will not produce high rates of complete remission in patients with advanced esophageal or other cancers, the possibility that the registration trial for OPAXIO as a radiation sensitizer will not occur, the possibility that CTI may not meet with the FDA in the second half of 2010, the possibility that the FDA will not approve a phase III registration strategy for paclitaxel poliglumex if proposed by CTI, CTI's ability to continue to raise capital as needed to fund its operations, competitive factors, technological developments, and costs of developing, producing and selling OPAXIO. You should also review 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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