NSABP B-38: Definitive analysis of a randomized adjuvant trial comparing dose-dense (DD) AC→paclitaxel (P) plus gemcitabine (G) with DD AC→P and with docetaxel, doxorubicin, and cyclophosphamide (TAC) in women with operable, node-positive breast cancer.

Abstract

LBA1000 Background: The primary aims were to determine whether adjuvant DD AC→PG will be superior to DD AC→P as well as to TAC in DFS and to compare the relative DFS of TAC and DD AC→P. Secondary endpoints include survival and toxicity. Methods: From Nov 3, 2004 to May 3, 2007, 4894 women were randomized; 1630 to TAC (docetaxel [T] 75 mg/m2, doxorubicin [A] 50 mg/m2, cyclophosphamide [C] 500 mg/m2 q3 wks x 6), 1634 to DD AC→P (A 60 mg/m2 and C 600 mg/m2 q2 wks x 4 followed by P 175 mg/m2 q2 wks x 4), and 1630 to DD AC→PG (A 60 mg/m2 and C 600 mg/m2 q2 wks x 4 → P 175 mg/m2 + G 2000 mg/m2q2 wks x 4). Primary G-CSF support was required and erythropoiesis-stimulating agents (ESA) were used at investigator discretion. 52% were postmenopausal, 65% had 1 - 3 positive nodes, and 80% had HR+ breast cancer. Log-rank tests were used for pair-wise comparisons of the primary (DFS) and secondary (OS) endpoints among the three treatment arms. Results: With 64 months median follow-up, 5-year DFS in DD AC→PG group was 80.6% compared with 82.2% in DD AC→P group (HR=1.1; p=0.27) and 80.1 % (HR=0.97; p=0.71) in TAC group. 5-year OS was 90.8% in DD AC→PG group as compared with 89.1% (HR=.89; p=0.25) in DD AC→P group and 89.6 % (HR=0.90; p=0.32) in TAC group. HR for DFS and OS of DD AC→P vs. TAC were 0.89 (p=0.14) and 1.01 (p=0.92) respectively. Toxicities for TAC, DD AC→P, DD AC→PG, respectively: febrile neutropenia (Gr 3/4: 9%, 4%, 4% [p<0.001]), sensory neuropathy (Gr 3/4: <1%, 7%, 6% [p<0.001]), diarrhea (Gr 3/4: 8 %, 2%, 2% [p<0.001]). Hgb was <10 in 12%, 26%, 33% with ESA use in 35.2%, 47%, 51.6% and transfusions in 3.7%, 6.3%, 9.4%. Deaths on treatment: N=13, 5, 7 (p=0.2). AML/MDS: N=5, 8, 11. All cycles completed in 91% for TAC and 88% for DD regimens. Conclusions: Addition of G to DD AC→P did not improve outcomes. No significant differences in efficacy endpoints were identified between DD AC→P and TAC, though toxicity profiles differed. Funding: NCI PHS U10-CA-37377, -69974, -12027, -69651 and NCCTG U10-CA25224, with additional funding from Eli Lilly & Company, and Amgen, Inc.