TP10 is a complement inhibitor developed by AVANT for applications including the limitation of complement-mediated damage following surgery on cardiopulmonary bypass. In February 2002, AVANT announced that TP10 had not achieved a significant reduction in the primary endpoint of death, myocardial infarction, prolonged intubation or prolonged intra-aortic balloon pumping following preliminary analysis of a Phase 2 adult cardiac surgery trial conducted in 564 patients. However, further analysis of the study data demonstrated an important treatment benefit to male patients participating in the trial, with no significant treatment benefit to female patients. Adverse events reported following treatment with TP10 were generally similar to those seen in placebo treated patients and were said by investigators to be routinely observed following cardiopulmonary bypass.

In March 2006 AVANT reported results of its Phase 2b study of TP10 in 300 women undergoing high risk cardiac surgery utilizing cardiopulmonary bypass (CPB). The objective of this study was to assess the safety of TP10 and its ability to reduce the incidence of death and myocardial infarction in females. The previous Phase II in cardiac surgery patients on CPB, discussed above, had demonstrated statistically significant efficacy in males but not in females. This females-only study confirmed the lack of benefit in women, setting the path forward for pursuit of a males-only indication, representing 75% of the market.

AVANT is seeking to partner the TP10 program prior to starting a Phase 3 trial.