Cell Therapeutics, Inc. (CTI) announced results from a study released by Dartmouth-Hitchcock Medical Center at the International Association for the Study of Lung Cancer (IASLC) 13th World Conference on Lung Cancer. The study demonstrated that in patients with advanced non-small cell lung cancer (NSCLC), the combination of Opaxio (paclitaxel poliglumex) and Alimta (pemetrexed) was well tolerated and resulted in median progression-free survival of 3.3 months.
The study, led by Dr. J. R. Rigas, enrolled twelve patients, six to each of two dose levels. Patients were treated in 21-day cycles, with cohort one receiving 135 mg/m2 of paclitaxel poliglumex and 500 mg/m2 of pemetrexed, and cohort two receiving 175 mg/m2 of paclitaxel poliglumex and 500 mg/m2 of pemetrexed. None of the patients in cohort one had an initial dose-limiting toxicity (IDLT) with two cycles of therapy. There was one IDLT of infection with neutropenia in cohort two. Aside from grade 3 fatigue in two patients, there were no grade 3 or greater non-haematologic toxicities. A median of 4.5 cycles was delivered in each cohort.
The best response was stable disease in nine patients. Two patients remain without evidence of disease progression, and six patients were alive at time of data presentation. Median progression free survival was 3.3 months.
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 tumour 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 tumours due to their leaky blood vessels and trapped in the tumour bed allowing significantly more of the dose of chemotherapy to localize in the tumour than with standard paclitaxel. Once inside the tumour cell, enzymes metabolize the protein polymer, releasing the paclitaxel chemotherapy. Preclinical and clinical studies support that Opaxio metabolism by lung cancer cells may be influenced by estrogen, which could lead to enhanced release of paclitaxel and efficacy in women with lung cancer compared to standard therapies.
Headquartered in Seattle, CTI is a biopharmaceutical company committed to developing an integrated portfolio of oncology products aimed at making cancer more treatable.