Berry, Donald A.

PurposeOptimal adjuvant chemotherapy for early-stage breast cancer balances efficacy and toxicity. We sought to determine whether single-agent paclitaxel (T) was inferior to doxorubicin and cyclophosphamide (AC), when each was administered for four or six cycles of therapy, and whether it offered less toxicity.Patients and MethodsPatients with operable breast cancer with 0 to 3 positive nodes were enrolled onto the study to address the noninferiority of single-agent T to AC, defined as the one-sided 95% upper-bound CI (UCB) of hazard ratio (HR) of T versus AC less than 1.30 for the primary end point of relapse-free survival (RFS). As a 2 × 2 factorial design, duration of therapy was also addressed and was previously reported.ResultsWith 3,871 patients enrolled onto the trial, a median follow-up period of 6.1 years, and 437 RFS events, we achieved an HR of 1.26 (one sided 95% UCB, 1.48; favoring AC does not allow a conclusion of noninferiority of T with AC; UCB > 1.3). With 266 patient deaths, the HR for overall survival (OS) was 1.27 favoring AC (UCB, 1.56). The estimated absolute advantage of AC at 5 years is 3% for RFS (91 v 88%) and 1% for OS (95 v 94%). All nine treatment-related deaths were patients receiving AC and are included in the analyses of both RFS and OS. Hematologic toxicity was more common in patients treated with AC, and neuropathy was more common in patients treated with T.ConclusionThis trial did not show noninferiority of T to AC, a conclusion that is unlikely to change with additional events and follow-up. T was less toxic than AC.

Abstract New approaches to drug development are critically needed to lessen the time, cost, and resources necessary to identify and optimize active agents. Strategies to accelerate drug development include testing drugs earlier in the disease process, such as the neoadjuvant setting. The U.S. Food and Drug Administration (FDA) has issued guidance designed to accelerate drug approval through the use of neoadjuvant studies in which the surrogate short-term endpoint, pathologic response, can be used to identify active agents and shorten the time to approval of both efficacious drugs and biomarkers identifying patients most likely to respond. However, this approach has unique challenges. In particular, issues of patient safety are paramount, given the exposure of potentially curable patients to investigational agents with limited safety experience. Key components to safe drug development in the neoadjuvant setting include defining a study population at sufficiently poor prognosis with standard therapy to justify exposure to investigational agents, defining the extent and adequacy of safety data from phase I, detecting potentially harmful interactions between investigational and standard therapies, improving study designs, such as adaptive strategies, that limit patient exposure to ineffective agents, and intensifying safety monitoring in the course of the trial. The I-SPY2 trial is an example of a phase II neoadjuvant trial of novel agents for breast cancer in which these issues have been addressed, both in the design and conduct of the trial. These adaptations of phase II design enable acceleration of drug development by reducing time and cost to screen novel therapies for activity without compromising safety. Clin Cancer Res; 19(11); 2817–23. ©2013 AACR.

PurposeThe ideal duration of adjuvant chemotherapy for patients with lower risk primary breast cancer is not known. Cancer and Leukemia Group B trial 40101 was conducted using a phase III factorial design to define whether six cycles of a chemotherapy regimen are superior to four cycles. We also sought to determine whether paclitaxel (T) is as efficacious as doxorubicin/cyclophosphamide (AC), but with reduced toxicity.Patients and MethodsBetween 2002 and 2008, the study enrolled women with operable breast cancer and zero to three positive nodes. Patients were randomly assigned to either four or six cycles of either AC or T. Study stratifiers were estrogen receptor/progesterone receptor (ER/PgR), human epidermal growth factor receptor 2 (HER2), and menopausal status. After 2003, all treatment was administered in dose-dense fashion. The primary efficacy end point was relapse-free survival (RFS).ResultsA total of 3,171 patients were enrolled; 94% were node-negative and 6% had one to three positive nodes. At a median follow-up of 5.3 years, the 4-year RFS was 90.9% and 91.8% for six and four cycles, respectively. The adjusted hazard ratio (HR) of six to four cycles regarding RFS was 1.03 (95% CI, 0.84 to 1.28; P = .77). The 4-year OS was 95.3% and 96.3% for six and four cycles, respectively, with an HR of six to four cycles of 1.12 (95% CI, 0.84 to 1.49; P = .44). There was no interaction between treatment duration and chemotherapy regimen, ER/PgR, or HER2 status on RFS or OS.ConclusionFor women with resected primary breast cancer and zero to three positive nodes, we found no evidence that extending chemotherapy regimens of AC or single-agent T from four to six cycles improves clinical outcome.

Abstract Purpose: p53 as a prognostic and predictive factor in early-stage breast cancer has had mixed results. We studied p53 protein expression, by immunohistochemistry, in a randomized clinical trial of stage II patients treated with adjuvant doxorubicin and cyclophosphamide with or without paclitaxel [Cancer and Leukemia Group B (CALGB) 9344, INT0148]. Patients and Methods: Epithelial p53 expression was evaluated using two immunohistochemical antibodies (DO7 and 1801) in formalin-fixed, paraffin-embedded tissue from patients with node-positive breast cancer who were randomized to four cycles of cyclophosphamide and one of three doses of doxorubicin (60, 75, or 90 mg/m2; AC) and to receive four subsequent cycles of paclitaxel (T) or not. Prognostic and predictive value of p53 protein expression was assessed, independent of treatment assignment, for escalating doses of doxorubicin or addition of T with endpoints of relapse-free (RFS) and overall survival (OS). Results: Of 3,121 patients, 1,887 patient specimens treated on C9344 were obtained, passed quality control, and evaluated for p53 expression. Expression was 23% and 27% for mAbs 1801 and D07, respectively, with 92% concordance. In univariate analysis, p53 positivity was associated with worse OS with either antibody, but only p53 staining with monoclonal antibody 1801 had significantly worse RFS. In multivariate analysis, p53 was not predictive of RFS or OS from either doxorubicin dose escalation or addition of paclitaxel regardless of the antibody. Conclusion: Nuclear staining of p53 by immunohistochemistry is associated with worse prognosis in node-positive patients treated with adjuvant doxorubicin-based chemotherapy but is not a useful predictor of benefit from doxorubicin dose escalation or the addition of paclitaxel. Clin Cancer Res; 17(15); 5170–8. ©2011 AACR.

Abstract Background: An estimated 1.3 million women worldwide will be diagnosed this year with early stage breast cancer. The majority of women have estrogen receptor (ER) positive breast cancer and are candidates for endocrine therapy. Tamoxifen remains the most commonly employed agent worldwide and substantially reduces recurrence and mortality. Tamoxifen is a pro-drug. CYP2D6 converts tamoxifen to endoxifen, which is primarily responsible for inhibition of estrogen-stimulated breast cancer growth in vitro. There have been conflicting reports regarding the relationship between CYP2D6 genotype/phenotype and tamoxifen clinical outcome. The ITPC was established to collect the worldwide experience relating to genetic variation in CYP2D6 and the outcomes of women with ER positive breast cancer treated with adjuvant tamoxifen. Establishment of the predictive value of CYP2D6 would enable the a priori identification of patients that could be spared ineffective therapy.Methods: Individual patient data including tumor characteristics, genotype, medication data, and recurrence information were requested from all published and non-published reports of clinical outcomes related to CYP2D6 and deposited at PharmGKB. CYP2D6 genotype was available for the following null (*3, 4, 5 and 6) and IM (*10, 17 and 41) alleles. CYP2D6 inhibiting medication data was requested for weak and potent CYP2D6 inhibitors. The primary analysis was to determine the association of CYP2D6 phenotype (combined genotype and medication) with breast cancer recurrence in tamoxifen treated early stage, ER positive invasive breast cancer.Results: At this time, the ITPC has received patient data on 3432 patients from the U.S., Sweden, UK, Germany, Belgium, and Japan. Median age at diagnosis was 62 years. CYP2D6 genotype was available in 3,392 (99%). The allele frequency for CYP2D6*4, the most common allele associated with the CYP2D6 poor metabolizer phenotype, was q=0.23. A total of 1152 recurrences representing first events (either local, regional, distant, or contralateral breast cancer) were recorded. At the time of abstract submission, patient and genotype data from an additional 1300 tamoxifen treated patients were pending submission.Conclusions: The ITPC represents the largest collection of individual patient data in regard to the potential importance of CYP2D6 phenotype in adjuvant tamoxifen therapy. The findings from this consortium are expected to substantially improve the global understanding of CYP2D6 and tamoxifen clinical outcome. Final results will be presented at the meeting Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 33.

Purpose Patient adherence is critical in evaluating the effectiveness of an oral therapy. We sought to measure adherence among women randomly assigned to capecitabine in a preplanned substudy of a multicenter clinical trial. Patients and Methods Cancer and Leukemia Group B study CALGB 49907 was a randomly assigned trial comparing standard chemotherapy versus oral chemotherapy with capecitabine in patients age 65 years or older with early-stage breast cancer. We used microelectronic monitoring system (MEMS) caps on participants' capecitabine bottles to record pill bottle openings. Capecitabine was given in two divided daily doses for 14 consecutive days of a 21-day cycle for six cycles. Adherence was calculated as the number of doses taken divided by doses expected, taking into account toxicity-related dosing changes. A participant was defined as adherent if 80% or more of expected doses were recorded by MEMS. Results Overall, 161 patients were enrolled. Median age was 71 years (range, 65 to 89 years); 124 patients (83%) persisted with capecitabine to completion of planned protocol therapy. Adherence was 78% across all cycles, and adherence did not vary by cycle (P = .32). Twenty-five percent of participants took fewer than 80% of expected doses and were nonadherent. In a logistic regression model, participants with node-negative disease (P = .01) and mastectomy (P = .01) were more likely to be nonadherent. Adherence was not related to age, tumor stage, or hormone receptor status. Adherence was not significantly associated with relapse-free survival or grade 3 or 4 toxicity. Conclusion Most older women with early-stage breast cancer were adherent to short-term oral chemotherapy in a randomized clinical trial. Age was not associated with adherence.

Abstract The optimal design of phase II studies continues to be the subject of vigorous debate, especially studies of newer molecularly targeted agents. The observations that many new therapeutics “fail” in definitive phase III studies, coupled with the numbers of new agents to be tested as well as the increasing costs and complexity of clinical trials, further emphasize the critical importance of robust and efficient phase II design. The Clinical Trial Design Task Force (CTD-TF) of the National Cancer Institute (NCI) Investigational Drug Steering Committee (IDSC) has published a series of discussion papers on phase II trial design in Clinical Cancer Research. The IDSC has developed formal recommendations about aspects of phase II trial design that are the subject of frequent debate, such as endpoints (response versus progression-free survival), randomization (single-arm designs versus randomization), inclusion of biomarkers, biomarker-based patient enrichment strategies, and statistical design (e.g., two-stage designs versus multiple-group adaptive designs). Although these recommendations in general encourage the use of progression-free survival as the primary endpoint, randomization, inclusion of biomarkers, and incorporation of newer designs, we acknowledge that objective response as an endpoint and single-arm designs remain relevant in certain situations. The design of any clinical trial should always be carefully evaluated and justified based on characteristic specific to the situation. Clin Cancer Res; 16(6); 1764–9