Evaluating the effectiveness of darbepoetin alfa 300 mcg Q3W for the treatment of chemotherapy-induced anemia

Abstract

8129 Background: Darbepoetin alfa (DA) 200 mcg Q2W has been shown to be as effective as epoetin alfa (EA) 40000 U QW for the treatment of chemotherapy-induced anemia (CIA; Schwartzberg 2004). In this controlled study, 82% of pts treated with DA 200 mcg Q2W achieved the target Hb (≥ 11g/dL) in a median time of 5 weeks (wks), compared with 86% of pts treated with EA in a median time of 4 wks. In addition, 16% of pts treated with DA and 17% treated with EA required transfusions. Administration of DA Q3W could offer the possibility to synchronize anemia therapy with chemotherapy. Methods: This 16-wk, single-arm, open-label study is designed to assess the effectiveness of DA 300 mcg Q3W in achieving and maintaining a target Hb consistent with evidence-based guidelines (11–12g/dL) in patients (pts) with CIA. Secondary endpoints include transfusion incidence, change in Hb from baseline (BL) and Pt-reported outcomes (assessed by the FACT-F). DA could be increased after 6 wks (2 doses) based on pt response. At any time, DA could be withheld or reduced if Hb increased rapidly or Hb threshold was reached. This interim analysis includes 634 pts enrolled before 14 Jun 2004 who completed 16 wks of treatment and is stratified by BL Hb of <10 and ≥10g/dL. Results: Most pts were female (61%) and white (81%) with a median age of 64 yrs. The most common tumors were lung (24%) and breast (22%). The majority of pts, regardless of BL Hb, achieved and maintained target Hb (Table). For pts with BL Hb < 10g/dL, substantial increases in Hb and FACT-F scores were observed. Safety results were consistent with those described for other DA studies. Conclusions: DA 300 mcg Q3W is well-tolerated and effective for achieving and maintaining evidence-based target Hb levels in pts with CIA, allowing the opportunity to synchronize the administration of DA with common chemotherapy regimens. Baseline Hb < 10 g/dL (n = 192) Baseline Hb = 10 g/dL (n = 411) Overall (n = 634) Mean (SD) baseline Hb 9.3 g/dL (0.5) 10.6 g/dL (0.3) 10.2 g/dL (0.7) (n = 603) % (95% CL) of pts achieving Hb target (K-M method) 79% (72, 86) 91% (88, 94) 88% (85, 91) (n = 633) Median (Q1, Q3) time to Hb target (K-M method) 9 weeks (4, 16) 3 weeks (2, 7) 4 weeks (2, 11) Mean (95% CL) Hb after achieving target Hb level 11.5 g/dL (11.4, 11.7) (n = 130) 11.5 g/dL(11.5, 11.6) (n = 353) 11.5 g/dL (11.5, 11.6) (n = 507) Mean (95% CL) change in Hb from baseline at week 16 (LVCF approach) 1.6 g/dL (1.3, 1.8) 0.8 g/dL (0.7, 1.0) 1.1 g/dL (0.9, 1.2) (n = 603) Mean (95% CL) change in Hb from baseline at week 16 (availble data approach) 2.2 g/dL (1.9, 2.5) (n = 123) 1.1 g/dL (0.9, 1.3) (n = 289) 1.4 g/dL (1.3, 1.6) (n = 412) Percent (95% CL) of pts with a transfusion (week 5 to EOTP) 31% (24, 38) (n = 179) 14% (11, 18) (n = 395) 20% (17, 23) (n = 602) Mean (95% CL) change in FACT-F from baseline at week 16 (available data approach) 4.7 (2.3, 7.1) (n = 128) 2.9 (1.2, 4.6) (n = 291) 3.5 (2.2, 4.9) (n = 424) Average (95% CL) Q3W dose administered 337 mcg (328, 345) 324 mcg (319, 330) 328 mcg (324, 333) Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Amgen Amgen, Genentech Amgen