This was an international single blind phase-III study of patients undergoing orthopaedic surgery to assess the efficacy and safety of HBOC-201. Patients who were expected to require two or more units of red blood cells (RBC) were randomised to HBOC-201 or RBC. Efficacy was defined as the proportion of patients in the HBOC-201 group who did not receive RBC. The HBOC-201 group comprised 350 patients and the RBC group 338. At randomisation, mean haemoglobin levels were similar (~9 g/dl) in the two groups (p =0.760). In the HBOC-201 group, transfusion was avoided in 337 patients (96.3%) on day one, 246 patients (70.3%) through day seven, and 208 patients (59.4%) through day 42. Fewer units of allogeneic red cell units were administered in the HBOC-201 group than in the RBC group, namely 1.4 units v 3.1 units (p < 0.001).

Adverse events in the HBOC-201 group were transient and mild in intensity and did not result in discontinuation of HBOC-201. There was no significant difference in mortality between the groups (p.=0.450). The efficacy of HBOC-201 was demonstrated by the avoidance of allogeneic RBC in about 60% of patients receiving this oxygen-carrying solution over a six-week period. HBOC-201 was well tolerated and appears to be a feasible alternative to RBC.