More disappointment for pexelizumab

November 24, 2005

Cheshire, CT - Alexion Pharmaceuticals has reported that its phase 3 clinical trial, Pexelizumab for Reduction of Infarction and Mortality in Coronary Artery Bypass Graft Surgery 2 (PRIMO-CABG2), has failed to show a significant reduction in its primary end point.

Pexelizumab, a terminal complement inhibitor, is a monoclonal antibody fragment that inhibits complement-mediated tissue damage. PRIMO-CABG2 included approximately 4250 patients and compared the safety and efficacy of pexelizumab in CABG patients.

The primary end point was the combined incidence of death or MI at 30 days following CABG. Alexion notes that there was a trend toward a reduction of the primary end point in the pexelizumab group, but this did not meet the prespecified threshold for statistical significance. Full results will be presented at an upcoming scientific meeting.

Alexion says it is assessing the implications of these results on its second pivotal phase 3 study of pexelizumab, the APEX-AMI trial, which is investigating the use of pexelizumab in MI patients treated with primary PCI.

This is the second major study of pexelizumab in CABG patients that has failed to show a significant reduction in the primary end point. The first trial, PRIMO-CABG, which was published last year, showed similar results, with a nonsignificant trend toward a reduction in death/MI. In that trial, a significant reduction in death/MI was seen in the subgroup of patients judged to be high risk. The PRIMO-CABG2 trial was therefore conducted in a higher-risk group, so it is particularly disappointing that the results of this trial were not significant.


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