A team of clinical investigators from the University of SouthernCalifornia/Norris Comprehensive Cancer Center announcedMonday that they are ready to begin Phase II clinical trials ona potential vaccine for treating breast cancer.
This will be the first U.S. trial for the vaccine, Theratope STn-KLH, which is produced by the Canadian company BioMira Inc.The FDA approved the Phase II protocol on Oct. 1. BioMira(NASDAQ:BIOMF) has already conducted Phase I safety studieson the vaccine and is currently in the midst of a number ofPhase II breast cancer trials at several Canadian cancer centersand at Guy's Hospital in London.
"Results from the Phase I study in Canada (on 13 patients withmetastatic breast cancer) indicate a significant reduction in thesize of tumors associated with cancer of the breast," saidMalcolm Mitchell, a professor of medicine and microbiology atUSC and the lead clinical investigator. BioMira's senior vicepresident of research, B. Michael Longenecker, presented thosedata last Saturday at the First International Conference onEngineered Vaccines for Cancer and AIDS held in San Francisco.
The vaccine consists of an antigen that is commonly found onmany types of solid tumors, including breast, colon andpancreatic cancers. It's actually a carbohydrate moiety --primarily galactose -- attached via its sialyl residue to thecarrier keyhole limpet hemacyanin, which has a molecularweight of about 400,000. This carrier increases thecarbohydrate antigen's immunogenicity, explained AlexMcPherson, BioMira's president and chief executive officer.
To further boost immunogenicity, the components are thenmixed with Ribi ImmunoChem Research's (NASDAQ:RIBI)adjuvant Detox, which is derived from bacterial endotoxin andcell wall skeletons.
The Phase II studies at USC/Norris will enroll 45 women whosebreast cancer is considered to be in its earliest stages ofmetastasis. To qualify for participation, the women must haveminimal evidence of metastatic cancer but measurable lesionsin the lung, liver, or lymph nodes, McPherson told BioWorld. Headded that they also must have been treated previously withadjunct therapy (tamoxifen or chemotherapy).
Together with the non-U.S. Phase II trials, there are 269patients slated to participate in these breast cancer vaccinetrials -- of which 75 are already enrolled, McPherson toldBioWorld. The studies will continue to evaluate Theratope'ssafety, as well as determine its efficacy, optimum dosage levelsand frequency of injections.
-- Jennifer Van Brunt Senior Editor
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