Initial evaluation of a human immunoglobulin M monoclonal antibody (HA-1A) in humans

A human monoclonal antibody (HA-1A) directed against bacterial endotoxin was administered to 15 patients with incurable malignant disease. No adverse effects were noted following single intravenous infusions of 0.05 to 100 mg. Pharmacokinetics were evaluated in nine patients receiving 10 mg (n = 3), 25 mg (n = 3), and 100 mg (n = 3). Seven of these patients had initial peak serum concentrations >80% of predicted values with plasma disappearance curves fitting a one-compartment system and a plasma half-life of 31.5 h (range of 20.3-44.6 h). The peak serum concentrations and area under the curve values were proportional to the dose of HA-1A administered. One patient had a hypercatabolic state with low levels of serum albumin and IgM. He achieved 65% of the predicted value for peak serum concentration of HA-1A with a plasma half-life of 12.3 h. A second patient had detectable serum HA-1A for only 15 min following infusion without an adequate technical or biologic explanation. We were unable to demonstrate antibody to HA-1A in sera from these nine patients either prior to therapy or during 28 days postinfusion using a “double-antigen” radiometric assay. This study suggests that HA-1A human monoclonal antibody administration is well tolerated by patients. Phase I trials will need to be carried out to characterize further the pharmacokinetics and toxicity of HA-1 A in patients with gram-negative sepsis.