The relationship of body weight and efficacy of fixed dose epoetin alfa vs placebo

Abstract

8192 Background: Clinical studies have demonstrated that epoetin alfa is effective when administered once weekly (QW) at an initial fixed dose of 40,000 IU, increased to 60,000 IU for hemoglobin (Hb) increase <1 g/dL after 28 days. Methods: This analysis evaluated the relationship of body weight and efficacy in patients administered the fixed-dose regimen (FDR) of epoetin alfa and whether an FDR was effective across all weight ranges. Data from a placebo-controlled NCCTG/Mayo Clinic trial (n = 168 epoetin alfa; n = 165 placebo; Witzig 2004) were analyzed. Body weights were defined according to the European Cancer Anaemia Survey (ECAS) quartiles (≤60.3 kg, >60.3 kg to ≤70.0 kg, >70.0 kg to ≤79.5 kg, and >79.5 kg) (Ludwig 2004). Efficacy endpoints were erythropoietic response (postbaseline Hb ≥12 g/dL or Hb increase from baseline ≥2 g/dL, independent of transfusion); transfusion or Hb ≤8 g/dL after 28 days; and change in Hb from baseline. Results: Demographic and baseline variables were similar between treatment groups. Median body weight was 72.9 and 71.8 kg for the epoetin alfa and placebo groups, respectively; mean baseline Hb was 9.4 g/dL for both groups. Percentage of patients with erythropoietic response in the epoetin alfa group by quartile (1st, 2nd, 3rd, and 4th) were 77%, 74%, 58%, and 74%; and for placebo were 35%, 19%, 30%, and 32% respectively. The interaction between treatment and body weight on response was not significant (P = 0.7187). In the 1st through 4th quartiles, 24%, 30%, 27%, and 30%, of placebo-treated patients received transfusion compared with 13%, 15%, 29%, and 11% of epoetin alfa-treated patients. The interaction between treatment and body weight was not significant (P = 0.3209). Mean Hb change from baseline for the 1st through 4th quartiles was 3.2, 3.4, 2.4, and 2.3 g/dL, respectively, for the epoetin alfa-treated patients and 1.2 0.7, 0.9, and 0.7 g/dL, respectively, for the placebo-treated patients. Again, the interaction between treatment and body weight was not significant (P = 0.3324). Conclusions: These data demonstrate that epoetin alfa administered at a fixed dose is effective over a broad range of patient weights. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Johnson & Johnson Ortho-Biotech