High Rates of Pathological Complete Response in Patients with Advanced Esophageal Cancer in OPAXIO™ Phase II Study

Cell Therapeutics, Inc. has announced that updated phase II study results of OPAXIO (paclitaxel poliglumex) in patients with advanced esophageal cancer conducted by the Brown University Oncology Group were published in the February 3, 2011 issue of the American Journal of Clinical Oncology, Dipetrillo, et al., which demonstrate that 38% (15/40) of the 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 in the study, 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.

"We are pleased to have the impressive and potentially important results of the paclitaxel poliglumex phase II esophageal study published in a peer reviewed journal," said Dr. Howard Safran, M.D., director of the Brown University Oncology Group. "In this study, the treatment was well tolerated and we did not see the severe side effects that are typically experienced with standard treatment options. If these data can be validated in a randomized controlled trial, the use of paclitaxel poliglumex along with cisplatin and radiation could provide an important treatment alternative for patients with lower esophageal cancer with an attractive risk-benefit profile."

The phase II study conducted by the Brown University Oncology Group 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 metastases. 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 (7%), esophagitis (7%), and fatigue (5%).

"This phase II study with OPAXIO demonstrated an encouragingly high rate of complete disappearance of cancer in patients that underwent potentially curative surgery following chemoradiotherapy. Moreover, the therapy had a low incidence of the severe inflammation of the esophagus that frequently requires a feeding tube observed with the current standard regimens," said Jack Singer, M.D., Chief Medical Officer of CTI. "We believe that this study provides preliminary clinical support to our belief that paclitaxel poliglumex is a potent and tumor-selective radiosensitizer."