Tiffany A. Traina

PIK3CA mutation associates with improved outcome in breast cancer.

Purpose: In breast cancer, somatic mutations in the PIK3CA gene are common. The prognostic implication of these activating mutations remains uncertain as moderately sized studies have yielded variable outcomes. Our aim was to determine the prognostic implications of PIK3CA mutations in breast cancer. Experimental Design: Archival formalin-fixed paraffin-embedded primary breast tumors, from 590 patients selected for known vital status with a median follow-up of 12.8 years and a tumor >1 cm, were genotyped for PIK3CA mutations. Mutation rates and associations between mutation site and clinicopathologic characteristics were assessed. Progression-free survival, overall survival, and breast cancer–specific survival were examined using Kaplan-Meier or competing risk methodology. Results: PIK3CA mutation is identified in 32.5% of breast cancers. PIK3CA mutation significantly associates with older age at diagnosis, hormone receptor positivity, HER2 negativity, lower tumor grade and stage, and lymph node negativity. Patients with PIK3CA mutated tumors have significant improvement in overall survival (P = 0.03) and breast cancer–specific survival (P = 0.004). Analysis for PIK3CA mutation site-specific associations reveals that the H1047R kinase domain mutation highly associates with node negativity (P = 0.007), whereas helical domain hotspot mutations associate with older age at diagnosis (P = 0.004). Conclusion: This study defines the positive prognostic significance of PIK3CA mutations. This work is clinically relevant, as it will significantly affect the design of clinical trials planned for phosphatidylinositol 3-kinase–targeted therapy. Future work may define a population of older age breast cancer patients in whom therapy can be minimized. (Clin Cancer Res 2009;15(16):5049–59)

Phase II trial of bicalutamide in patients with androgen receptor-positive, estrogen receptor-negative metastatic breast cancer

Purpose: Patients with hormone receptor–negative breast cancer generally do not benefit from endocrine-targeted therapies. However, a subset with androgen receptor (AR) expression is predicted to respond to antiandrogen therapies. This phase II study explored bicalutamide in AR-positive, estrogen receptor (ER), and progesterone receptor (PgR)-negative metastatic breast cancer. Experimental Design: Tumors from patients with ER/PgR-negative advanced breast cancer were tested centrally for AR [immunohistochemistry (IHC) > 10% nuclear staining considered positive]. If either the primary or a metastatic site was positive, patients were eligible to receive the AR antagonist bicalutamide at a dose of 150 mg daily. Clinical benefit rate (CBR), the primary endpoint, was defined as the total number of patients who show a complete response (CR), partial response (PR), or stable disease (SD) > 6 months; secondary endpoints included progression-free survival (PFS) and toxicity. Correlative studies included measurement of circulating endocrine markers and IHC surrogates for basal-like breast cancer. Results: Of 424 patients with ER/PgR-negative breast cancer, 12% tested AR-positive. The 6-month CBR was 19% [95% confidence interval (CI), 7%–39%] for bicalutamide. The median PFS was 12 weeks (95% CI, 11–22 weeks). Bicalutamide was well-tolerated with no grade 4/5 treatment-related adverse events observed. Conclusion: AR was expressed in 12% of patients with ER/PgR-negative breast cancer screened for this trial. The CBR of 19% observed with bicalutamide shows proof of principle for the efficacy of minimally toxic androgen blockade in a select group of patients with ER/PgR-negative, AR-positive breast cancer. Clin Cancer Res; 19(19); 5505–12. ©2013 AACR.

Androgen Receptor Levels and Association with PIK3CA Mutations and Prognosis in Breast Cancer

Purpose: To examine the androgen receptor (AR) levels in breast cancer and to assess the impact of AR expression on patient outcomes. Experimental Design: Reverse-phase protein arrays were used to measure AR levels and a mass spectroscopy–based approach was used to detect PIK3CA mutations. Means and SDs were generated for AR levels. Linear regression models were used to determine if AR levels differed by tumor subtype and PIK3CA mutation status. Two-sample t tests were used to identify pair-wise differences. Survival probabilities were estimated with the use of the Kaplan-Meier product and log-rank test. Results: The median age was 59 years (23-89 years). Significant differences in AR levels existed among different breast tumor subtypes (highest in estrogen receptor–positive and/or progesterone receptor–positive tumors) as well as by PIK3CA mutation status (P < 0.0001 for both). AR levels were significantly higher in breast tumors with kinase domain PIK3CA mutations versus tumors that are wild type or with PIK3CA helical mutations (P = 0.017 and P < 0.0001, respectively). In 347 patients, dichotomized AR level by the median was a significant prognostic factor of recurrence-free survival (P = 0.0002) and overall survival (P = 0.004). High AR levels were associated with a significantly improved recurrence-free survival in 207 patients with early-stage estrogen/progesterone receptor–positive tumors after adjuvant hormonal therapy. A trend (P = 0.07) was found toward higher AR expression in PIK3CA mutant versus PIK3CA wild-type triple-negative breast tumors. Conclusions: AR levels may represent a prognostic marker in breast cancers and may provide a valuable tool for selecting treatment. There was an association of PIK3CA mutation (kinase domain) with increased AR levels.

TBCRC009: A Multicenter Phase II Clinical Trial of Platinum Monotherapy With Biomarker Assessment in Metastatic Triple-Negative Breast Cancer

PURPOSE The identification of patients with metastatic triple-negative breast cancer (mTNBC) who are expected to benefit from platinum-based chemotherapy is of interest. We conducted a single-arm phase II clinical trial of single-agent platinum for mTNBC with biomarker correlates. PATIENTS AND METHODS Patients with mTNBC received first- or second-line cisplatin (75 mg/m(2)) or carboplatin (area under the concentration-time curve 6) by physicians choice once every 3 weeks. Coprimary end points were objective response rate (RR) and response prediction by p63/p73 gene expression. Secondary and exploratory end points included toxicity assessment, RR in cisplatin versus carboplatin, and RR in molecularly defined subgroups, including BRCA1/2 mutation carriers. RESULTS Patients (N = 86; 69 as first-line therapy) received cisplatin (n = 43) or carboplatin (n = 43). RR was 25.6% (95% CI, 16.8% to 36%) and was numerically higher with cisplatin (32.6%) than with carboplatin (18.7%). RR was 54.5% in patients with germline BRCA1/2 mutations (n = 11). In patients without BRCA1/2 mutations (n = 66), exploratory analyses showed that a BRCA-like genomic instability signature (n = 32) discriminated responding and nonresponding tumors (mean homologous recombination deficiency-loss of heterozygosity/homologous recombination deficiency-large-scale state transitions [HRD-LOH/HRD-LST] scores were 12.68 and 5.11, respectively), whereas predefined analysis by p63/p73 expression status (n = 61), p53 and PIK3CA mutation status (n = 53), or PAM50 gene expression subtype (n = 55) did not. Five of the six long-term responders alive at a median of 4.5 years lacked germline BRCA1/2 mutations, and two of them had increased tumor HRD-LOH/HRD-LST scores. CONCLUSION Platinum agents are active in mTNBC, especially in patients with germline BRCA1/2 mutations. A measure of tumor DNA repair function may identify patients without mutations who could benefit from platinum therapy agents. Prospective controlled confirmatory trials are warranted.

Triple-negative breast cancer: role of the androgen receptor.

The androgen receptor (AR), a member of the steroid hormone receptor family, is expressed in more than 70% of breast cancers and has been implicated in breast cancer pathogenesis. The role of the AR is of particular interest in patients with estrogen- and progesterone receptor negative and HER2-negative cancers, which represent ∼25% of all breast cancers. The “triple-negative” subset of tumors generally has a more aggressive clinical course and does not benefit from conventional endocrine targeted therapies. However, emerging evidence suggests that the AR may serve as a therapeutic target for a subset of triple-negative breast cancers. Herein, we review the role of the AR in breast cancer tumorigenesis and current progress and future directions in the development of AR-targeted therapies.

Phase II Trial of Saracatinib (AZD0530), an Oral SRC-inhibitor for the Treatment of Patients with Hormone Receptor-negative Metastatic Breast Cancer

BACKGROUND SRC activation is associated with cell migration, proliferation, and metastasis. Saracatinib is an oral tyrosine kinase inhibitor (TKI) selective for SRC. We performed this trial to evaluate the efficacy and safety of saracatinib monotherapy in patients with estrogen receptor (ER)(-) and progesterone receptor (PR)(-) metastatic breast cancer (MBC). PATIENTS AND METHODS Patients who had undergone ≤ 1 previous chemotherapy regimen for measurable ER(-) and PR(-) MBC received saracatinib 175 mg orally daily. The primary endpoint was disease control defined as complete response (CR) + partial response (PR) + stable disease (SD) > 6 months. Secondary endpoints included toxicity and progression-free survival (PFS). Levels of circulating tumor cells (CTCs) in response to therapy were measured over time. RESULTS Nine patients were treated on study. After a median of 2 cycles (range 1-3), no patient had achieved CR, PR, or SD >6 months. The median time to treatment failure was 82 days (12-109 days).The majority (89%) of patients discontinued saracatinib because of disease progression. One patient acquired potentially treatment-related grade 4 hypoxia with interstitial infiltrates and was removed from the study. Common adverse events included fatigue, elevated liver enzymes, nausea, hyponatremia, dyspnea, cough, and adrenal insufficiency. CONCLUSIONS These efficacy results were not sufficiently promising to justify continued accrual to this study. Based on this series, saracatinib does not appear to have significant single-agent activity for the treatment of patients with ER(-)/PR(-) MBC.

Phase II Trial of Weekly Nanoparticle Albumin-Bound Paclitaxel With Carboplatin and Trastuzumab as First-line Therapy for Women With HER2-Overexpressing Metastatic Breast Cancer

PURPOSE This multicenter phase II trial evaluated the efficacy and safety of weekly nanoparticle albumin-bound paclitaxel with carboplatin and weekly trastuzumab as first-line therapy for women with HER2-overexpressing metastatic breast cancer (MBC). PATIENTS AND METHODS We treated 32 patients who had measurable MBC that was HER2-positive defined by an immunohistochemical staining score of 3+ or gene amplification by fluorescence in situ hybridization, required for those with an IHC of 2+. Patients were treated with albumin-bound paclitaxel 100 mg/m2 and carboplatin at area under the curve (AUC) = 2 on days 1, 8, and 15 of a 28-day cycle. Trastuzumab was administered at 2 mg/kg weekly after a loading dose of 4 mg/kg. Because of hypersensitivity reactions occurring during carboplatin infusion numbers 6-8 in 4 of the first 13 patients with this premedication-free regimen, the protocol was amended for carboplatin and dosed at AUC = 6 day 1 each 28-day cycle, in lieu of introducing steroid prophylaxis. Patients were treated with 6 cycles and allowed to continue with all 3 drugs or trastuzumab alone if free of progression and unacceptable toxicity after 6 cycles. RESULTS The overall response rate (ORR) was 62.5% (95% CI, 45.7%-79.3%) with 3 confirmed complete responders (CRs; 9%) and 17 confirmed partial responses (PRs; 53%). An additional 6 patients (19%) had stable disease (SD) for greater than 16 weeks for a clinical benefit rate (ORR + SD > 16 weeks) of 81%. As of April 16, 2009, 20 patients (63%) had progressed with a median progression-free survival (PFS) of 16.6 months (95% CI, 7.5-26.5 months). Antitumor activity was similar for patients treated with weekly carboplatin and every-4-week carboplatin (ORR, 65% vs. 67%, respectively). Hematologic toxicities were the only grade 4 toxicities noted and were infrequent with grade 4 neutropenia in 3 patients (9%) and 1 febrile neutropenia. Grade 2/3 peripheral neuropathy was uncommon (13%/3%). CONCLUSION Weekly albumin-bound paclitaxel with carboplatin and trastuzumab is highly active in HER2-overexpressing MBC. In the absence of corticosteroid premedication, which we avoided with albumin-bound paclitaxel, carboplatin seems best dosed every 4 weeks rather than weekly because of carboplatin-associated hypersensitivity reactions. The regimen was very well tolerated with few grade 3 and 4 nonhematologic toxicities experienced, and severe hematologic toxicity and peripheral neuropathy were infrequent.

Phase I Study of a Novel Capecitabine Schedule Based on the Norton-Simon Mathematical Model in Patients With Metastatic Breast Cancer

PURPOSE This study was conducted to determine, in patients with advanced-stage breast cancer, the maximum tolerated dose (MTD) of capecitabine administered orally for 7 days followed by a 7-day rest (7/7), a schedule based on a mathematical method for the optimization of anticancer drug scheduling. PATIENTS AND METHODS Eligible patients had measurable, metastatic breast cancer. There was no limit to number of prior treatments. A standard, three-patients-per-cohort dose-escalation scheme used flat-dose capecitabine beginning at 1,500 mg orally twice daily (bid) on a 7/7 schedule. Each cohort was monitored for 28 days before escalation to the next cohort to assess for delayed toxicity. Response was evaluated radiographically every 12 weeks; toxicity was assessed every 2 weeks. RESULTS Twenty-one patients were treated on study. The most frequently reported treatment-related grade 2/3 adverse events were hand-foot syndrome (29%), leukopenia/neutropenia (24%), and fatigue (19%). Grade 3 toxicity was transient and easily managed. Three patients experienced grade 3 hand-foot syndrome; one of these patients had grade 3 diarrhea. There were no grade 4 events. The MTD of capecitabine 7/7 is 2,000 mg twice daily. CONCLUSION As predicted by mathematical modeling, capecitabine dosing for 7 days followed by a 7-day rest is well tolerated. Efficacy of this schedule is being determined in a phase II clinical trial in patients with advanced breast cancer.

OncoKB: A Precision Oncology Knowledge Base

PURPOSE With prospective clinical sequencing of tumors emerging as a mainstay in cancer care, there is an urgent need for a clinical support tool that distills the clinical implications associated with specific mutation events into a standardized and easily interpretable format. To this end, we developed OncoKB, an expert-guided precision oncology knowledge base. METHODS OncoKB annotates the biological and oncogenic effect and the prognostic and predictive significance of somatic molecular alterations. Potential treatment implications are stratified by the level of evidence that a specific molecular alteration is predictive of drug response based on US Food and Drug Administration (FDA) labeling, National Comprehensive Cancer Network (NCCN) guidelines, disease-focused expert group recommendations and the scientific literature. RESULTS To date, over 3000 unique mutations, fusions, and copy number alterations in 418 cancer-associated genes have been annotated. To test the utility of OncoKB, we annotated all genomic events in 5983 primary tumor samples in 19 cancer types. Forty-one percent of samples harbored at least one potentially actionable alteration, of which 7.5% were predictive of clinical benefit from a standard treatment. OncoKB annotations are available through a public web resource (http://oncokb.org/) and are also incorporated into the cBioPortal for Cancer Genomics to facilitate the interpretation of genomic alterations by physicians and researchers. CONCLUSION OncoKB, a comprehensive and curated precision oncology knowledge base, offers oncologists detailed, evidence-based information about individual somatic mutations and structural alterations present in patient tumors with the goal of supporting optimal treatment decisions.

Cognitive Impairment in Older Patients With Breast Cancer Before Systemic Therapy: Is There an Interaction Between Cancer and Comorbidity?

PURPOSE To determine if older patients with breast cancer have cognitive impairment before systemic therapy. PATIENTS AND METHODS Participants were patients with newly diagnosed nonmetastatic breast cancer and matched friend or community controls age > 60 years without prior systemic treatment, dementia, or neurologic disease. Participants completed surveys and a 55-minute battery of 17 neuropsychological tests. Biospecimens were obtained for APOE genotyping, and clinical data were abstracted. Neuropsychological test scores were standardized using control means and standard deviations (SDs) and grouped into five domain z scores. Cognitive impairment was defined as any domain z score two SDs below or ≥ two z scores 1.5 SDs below the control mean. Multivariable analyses evaluated pretreatment differences considering age, race, education, and site; comparisons between patient cases also controlled for surgery. RESULTS The 164 patient cases and 182 controls had similar neuropsychological domain scores. However, among patient cases, those with stage II to III cancers had lower executive function compared with those with stage 0 to I disease, after adjustment (P = .05). The odds of impairment were significantly higher among older, nonwhite, less educated women and those with greater comorbidity, after adjustment. Patient case or control status, anxiety, depression, fatigue, and surgery were not associated with impairment. However, there was an interaction between comorbidity and patient case or control status; comorbidity was strongly associated with impairment among patient cases (adjusted odds ratio, 8.77; 95% CI, 2.06 to 37.4; P = .003) but not among controls (P = .97). Only diabetes and cardiovascular disease were associated with impairment among patient cases. CONCLUSION There were no overall differences between patients with breast cancer and controls before systemic treatment, but there may be pretreatment cognitive impairment within subgroups of patient cases with greater tumor or comorbidity burden.