Safety and recovery of mononine in multiple-dose, high-dose regimens.

Prothrombin complex concentrates (PCCs) have been used for the treatment of hemorrhagic episodes in patients with hemophilia B but have been associated with a high incidence of thrombotic complications. Newer, ultrapure concentrates of factor IX contain less extraneous proteins than PCCs and are less thrombogenic in vitro. In this report, the results of clinical studies with Mononine (Armour Pharmaceutical Company), a purified factor IX concentrate prepared by monoclonal affinity chromatography, are described. Two studies were performed, a phase I/II clinical trial in 10 patients and a compassionate use study in 72 patients. The pharmacokinetics of Mononine were found to be similar to the pharmacokinetics of factor IX after administration of PCCs. In both studies, Mononine was well-tolerated and hemostatically effective when used in doses of up to 161 IU/kg in treatment courses of up to 67 infusions of Mononine. Patients with hepatitis and a prior history of thrombosis with PCCs tolerated Mononine with no evidence of thrombosis. The only thrombotic complication attributed to Mononine in the two studies was an episode of phlebitis at the site of an intravenous line in one patient. These studies indicate that Mononine is safe and effective in the treatment of hemorrhagic episodes in patients with hemophilia B.