REPLIGEN rPF4 PHASE II TRIAL FOR HEPARIN REVERSAL

REPLIGEN rPF4 PHASE II TRIAL FOR HEPARIN REVERSAL has been initiated in cardiac catheterization patients, & the company announced Nov. 22. The double-blind, multicenter study is comparing the ability of recombinant platelet factor-4 against the standard therapy of protamine to reverse heparin anticoagulation post-catheterization. The 40-patient study is being conducted at the University of North Carolina Hospitals and the University of Texas, Southwestern Medical Center. Phase I results were presented Nov. 10 by UNC lead investigator Gregory Dehmer, MD, at the American Heart Association's 66th Scientific Sessions in Atlanta. In that trial, 18 patients received a bolus of heparin following cardiac catheterization. They were then given 0.5, 1, 2.5 or 5 mg/kg of rPF4 over 1, 2 or 3 minutes. In 16 patients, activated partial thromboplastin time (aPTT), which the use of heparin increases, returned to "normal or near normal," Dehmer said. He summed up by declaring: "Intravenous PF4 can reverse the anticoagulant effects of heparin in man." None of the patients had the "adverse hemodynamic effects historically known to occur with protamine," Dehmer noted. The only clinical side effects reported were considered mild: transient fever, brief occipital pain and chills. The highest dose, 5 mg/kg given to three patients, "appear[ed] to be safe." Dehmer concluded that "PF4 has a favorable profile of side effects." rPF4 is also being studied in three open-label trials with Kaposi's sarcoma patients for efficacy and continued monitoring of safety. The Phase II intralesional study of 30 patients is a follow-on to a Phase I safety trial in which rPF4 was administered intralesionally to Kaposi's sarcoma patients. The Phase I trial in 12 patients at San Francisco General Hospital had indicated that there was no reportable toxicity from rPF4. A Phase I/II subcutaneous study of 20 KS patients at Norris Cancer Center, University of Southern California, is under way, as is a Phase I/II intravenous study of 18-20 patients at San Francisco General. These two trials are the first systemic administration of rPF4 for Kaposi's sarcoma. To develop rPF4, Repligen is going back to the public markets. On Nov. 23, the company filed a registration statement for an offering of 2.5 mil. shares of common stock. The proceeds "will be used to fund clinical trials, R&D efforts, manufacturing scale-up and facilities expansion," the company said. Underwriters are Lehman Brothers, Montgomery Securities and Robertson, Stephens.