Johnson and Johnson announced Thursday that it has received 160 reports of pure red-cell aplasia (PRCA) among users of the anemia drug Eprex (erythropoietin). Eprex's link to PRCA, a condition characterized by a near absence of red blood cell precursors that leaves many patients dependent on transfusions to survive, has been a concern in the medical community for months. In June, the U.S. Food and Drug Administration officially confirmed the drug's link to the disorder in a letter published in The New England Journal of Medicine. Last fall, Johnson & Johnson issued a warning letter to physicians concerning the potential for the side effect.

Health officials are becoming more concerned over the increasing number of PRCA cases involving Eprex patients. Nineteen cases were reported in June and July of this year. Only 45 cases were reported in 2001.