National cooperative rHu erythropoietin study in patients with chronic renal failure: a phase IV multicenter study. Report of National Cooperative rHu Erythropoietin Study Group.

Initial experience with recombinant human erythropoietin (rHuEPO, epoetin alfa) was gained through research protocols in which patient selection and management were tightly controlled. When epoetin alfa was approved for use by the Food and Drug Administration (FDA) these constraints were removed. The present study was designed to examine the medical and social impact of epoetin alfa therapy, as well as to document its safety and efficacy as it is used in clinical practice. From 1,000 to 2,000 patients at 100 to 200 centers will be enrolled and monitored for 1 year. Two groups of patients are being studied--those already receiving epoetin alfa at study entry and those new to epoetin alfa therapy. Demographic data are collected initially and detailed outcome data are collected monthly. This interim report presents data from 68 participating dialysis centers on 447 enrolled patients. To date, 89% of the patients are on in-center hemodialysis, while 9% are on home dialysis (79% continuous ambulatory peritoneal dialysis [CAPD], 14% continuous cyclic peritoneal dialysis [CCPD]). Preliminary analyses suggest this population is similar in age and cause of chronic renal failure to the overall US dialysis population, although whites and males are somewhat underrepresented. Of those already on epoetin alfa at study entry, 62% were receiving 3,000 to 9,000 U/wk. In addition, those already on epoetin alfa had better self-rated general health than those new to therapy. Outcomes and epoetin alfa usage patterns are currently being fully analyzed. Three-month follow-up data on a cohort of patients new to epoetin alfa indicate that the average dose in these patients is less than 100 U/kg/wk; two thirds of the doses were administered intravenously. Hematocrit levels increased over the 3 months from a level of 25.1% at entry to 30.6% by month 3. The percentage of cohort patients who were transfusion-independent increased from 85.1% at study entry to 95.7% by month 3. No increases in the incidence of adverse events occurred in the cohort group and no changes in the safety profile were indicated. These preliminary findings suggest that low doses of rHuEPO are being used in general, with a resultant low mean hematocrit. Thus, patients do not seem to be realizing the full potential beneficial effects of this remarkable agent.