Ellis, Georgiana K.

LBA537 Background: Between 10-1-02 and 12-01-05, SWOG 0012 accrued patients to a two-arm randomized trial, with formal participation from NCCTG and CTSU participation by other cooperative groups. Arm 1 gave A at 60 mg/m2 and C at 600 mg/m2 q 3 wk IV for 5 cycles, arm 2 A at 24 mg/m2/wk × 15 IV and C at 60 mg/m2/day PO for 15 wk with G at 5 mcg/kg/day × 6/7 weekly. Both groups then received T at 80 mg/m2/wk × 12, and proceeded to surgery with pCR by NSABP criteria at the primary site as the endpoint. A total of 372 were randomized, and we report here on 265 patients (pts) evaluable for outcome, including those who did not proceed to surgery. In arm 1, pCR was seen in 17% vs 27% in arm 2 (p = .06); when adjusted for hormone receptor status (ER-PR- in 49% on arm 1, 41% on arm 2) and disease type (locally advanced vs inflammatory), the odds ratio in favor of arm 2 is 1.98 (95% CI 1.05–3.74, p = .034). For ER- PR- pts, pCR rates for Arm 1 vs 2 were 26 vs 43%, while for those with ER or PR+, pCR rates were 9 vs 14%. Inflammatory pts showed a striking difference in pCR rates for arm 1 vs arm 2 (12 vs 33%, p = .033). HER 2 status (+ in 29%) did not predict response or interact with treatment. Grade 3/4 toxicities (arm 1 vs 2, %) were as follows: hand-foot syndrome (0 vs 13), neutropenia (47 vs 16), neutropenic infection (1.8 vs 0.6), stomatitis (2 vs 11), and nausea/vomiting (11 vs 5). Toxicity from T was grade 3 neuropathy in 10%, with grade 3 or 4 neutropenia in 12%. There were no treatment-related deaths. Continuous or “metronomic” chemotherapy with AC is superior to standard intermittent AC, and the pCR rate reported for the continuous arm is the highest reported in a cooperative group experience for this patient population. [Table: see text]

11051 Background: A serious complication associated with breast cancer treatment is the increased risk for development of therapy-related acute myeloid leukemia (t-AML). To evaluate and possibly identify patients (pts) at high risk for development of t-AML, the Southwest Oncology Group asked whether dose-intensive adjuvant regimens for high risk breast cancer pts induced genetic damage to hematopoietic stem cells (HSC), defined by the emergence of clonal hematopoiesis, an early marker of HSC damage. Methods: 274 pts consented to the clonal hematopoiesis study objective of S0012, a randomized clinical trial of standard doxorubicin and cyclophosphamide followed by weekly paclitaxel (arm 1, 129 pts) vs. weekly doxorubicin and daily oral cyclophosphamide plus G-CSF followed by weekly paclitaxel (arm 2, 145 pts) as neoadjuvant therapy for inflammatory and locally advanced breast cancer. Two different clonality assays were used: the HUMARA (HUMan Androgen Receptor) Assay to estimate the incidence of early genetic damage by clonal proliferation and microsatellite instability (MSI) testing at 5 loci (Bat 26, Bat 40, APC, Mfd, D2S123), common ‘hotspots‘ in t-AML, to screen for loss of heterozygosity or defective DNA mismatch repair mechanisms. Blood samples were evaluated prior to treatment and at 6 and 12 mos post-surgery for emergence of clonal hematopoiesis. Results: Of the 274 pts enrolled, follow-up clonal hematopoiesis samples were available for 195 pts; 96 pts on arm 1 and 99 pts on arm 2. Both HUMARA and MSI results were negative for clonal hematopoiesis in 96% of samples analyzed. In 14 cases, the HUMARA assay suggested that a clonal population was present, but MSI analysis was negative. No cases were HUMARA+/MSI+. With a median follow-up of 19.6 mos, only one pt has developed t-AML 3 yr 5 mos post randomization. Her clonal hematopoiesis test samples at 6 and 12 mos following treatment were negative. Conclusions: Clonal hematopoiesis assays performed within the first year following neoadjuvant therapy and surgery on S0012 failed to identify an emerging clonal HSC population. Longer clinical follow-up will be necessary to define the positive predictive value of detecting clonal hematopoiesis in the 14 HUMARA+/MSI- cases as a harbinger of t-AML. No significant financial relationships to disclose.

Purpose Patients with inflammatory breast cancer (IBC) or locally advanced breast cancer (LABC) were randomly assigned to 21-day doxorubicin and cyclophosphamide administered for five cycles (standard arm) versus weekly doxorubicin and daily oral cyclophosphamide administered with granulocyte colony-stimulating factor support for 15 weeks (continuous arm). All patients had subsequent weekly paclitaxel for 12 weeks before surgery. Patients and Methods Patients (n = 372) were randomly assigned to the standard arm (n = 186) or the continuous arm (n = 186) stratified by disease type (LABC, n = 256; IBC, n = 116). The primary outcome was microscopic pathologic complete response (pCR) at surgery. Secondary outcomes included disease-free survival, overall survival, and toxicity. Results More patients in the standard arm had grade 3 to 4 leukopenia and neutropenia, but there were more instances of stomatitis/pharyngitis and hand-foot skin reaction in the continuous arm. Assessed among 356 eligible patients, pCR was not different between the treatment groups stratified by disease type (P = .42). In subset analysis, higher pCR rates were observed in the continuous arm versus the standard arm only for stage IIIB disease (P = .0057) and in IBC (P = .06). Comparison of overall survival and disease-free survival showed no difference between treatment groups (P = .37 and P = .87, respectively). Conclusion No significant clinical benefit was seen for the investigational arm in this trial overall.