PREDICTION OF RESPONSE TO RECOMBINANT-HUMAN-ERYTHROPOIETIN (RHUEPO) IN ANEMIA OF MALIGNANCY

Background. Since only a portion of anemic patients outside the uremia setting benefit from erythropoietin treatment, a reliable means of pr edicting potential responders and nonresponders would be very useful. Materials and Methods. We retrospectively reviewed the clinical record s of 58 patients with refractory anemia associated with various malign ant disorders who had been treated with subcutaneous rHuEpo. The start ing rHuEpo dose was 375 U/kg/week for 4 weeks, and was increased to 75 0 U/kg/week for another 4 weeks if no response was observed. Response was defined as a Hb increase greater than or equal to 2 g/dL with no n eed for blood transfusion. We examined the value of various laboratory parameters (baseline levels, 2-week and 4-week changes) as predictors of response. Endogenous erythropoietin production was evaluated by it s serum level and erythroid activity was assessed through reticulocyte count and circulating transferrin receptor. Results. Forty-eight indi viduals were evaluable, 58% of whom responded to rHuEpo within 8 weeks . Multiple regression analysis showed that 53% of the variation in the 8-week Hb concentration was explained by variations in baseline serum erythropoietin and the 2-week change in serum transferrin receptor (p < 0.001). Based on these two parameters, response prediction in indiv idual patients would have resulted in a sensitivity of 96%, a specific ity of 79% and an overall accuracy of 88%. In addition, 58% of the var iation in the 8-week Hb was explained by variations in the 4-week chan ges in Hb and reticulocyte count (p < 0.001). Utilizing these latter p arameters and baseline serum erythropoietin, response prediction in in dividual patients would have resulted in a sensitivity of 92%, a speci ficity of 82% and an overall accuracy of 88%. Conclusions. This retros pective analysis suggests that response to rHuEpo can be reasonably pr edicted by pretreatment serum erythropoietin together with early chang es in simple laboratory parameters.