Philippe L. Bedard

Tumour heterogeneity in the clinic

Recent therapeutic advances in oncology have been driven by the identification of tumour genotype variations between patients, called interpatient heterogeneity, that predict the response of patients to targeted treatments. Subpopulations of cancer cells with unique genomes in the same patient may exist across different geographical regions of a tumour or evolve over time, called intratumour heterogeneity. Sequencing technologies can be used to characterize intratumour heterogeneity at diagnosis, monitor clonal dynamics during treatment and identify the emergence of clinical resistance during disease progression. Genetic interpatient and intratumour heterogeneity can pose challenges for the design of clinical trials that use these data.

International Guidelines for Management of Metastatic Breast Cancer: Combination vs Sequential Single-Agent Chemotherapy

Compared with treatment options for early-stage breast cancer, few data exist regarding the optimal use of chemotherapy for metastatic breast cancer (MBC). The choice of using a combination of cytotoxic chemotherapies vs sequential single agents is controversial. At the 6th European Breast Cancer Conference, the European School of Oncology Metastatic Breast Cancer Task Force convened an open debate on the relative benefits of combination vs sequential therapy. Based on the available data, the Task Force recommends sequential monotherapy as the preferred choice in advanced disease, in the absence of rapid clinical progression, life-threatening visceral metastases, or the need for rapid symptom and/or disease control. Patient- and disease-related factors should be used to choose between combination and sequential single-agent chemotherapy for MBC. Additional research is needed to determine the impact of therapy on patient-rated quality of life and to identify predictive factors that can be used to guide therapy.

Elucidating Prognosis and Biology of Breast Cancer Arising in Young Women Using Gene Expression Profiling

Purpose: Breast cancer in young women is associated with poor prognosis. We aimed to define the role of gene expression signatures in predicting prognosis in young women and to understand biological differences according to age. Experimental Design: Patients were assigned to molecular subtypes [estrogen receptor (ER)+/HER2−; HER2+, ER−/HER2−)] using a three-gene classifier. We evaluated whether previously published proliferation, stroma, and immune-related gene signatures added prognostic information to Adjuvant! online and tested their interaction with age in a Cox model for relapse-free survival (RFS). Furthermore, we evaluated the association between candidate age-related genes or gene sets with age in an adjusted linear regression model. Results: A total of 3,522 patients (20 data sets) were eligible. Patients aged 40 years or less had a higher proportion of ER−/HER2− tumors (P < 0.0001) and were associated with poorer RFS after adjustment for breast cancer subtype, tumor size, nodal status, and histologic grade and stratification for data set and treatment modality (HR = 1.34, 95% CI = 1.10–1.63, P = 0.004). The proliferation gene signatures showed no significant interaction with age in ER+/HER2− tumors after adjustment for Adjuvant! online. Further analyses suggested that breast cancer in the young is enriched with processes related to immature mammary epithelial cells (luminal progenitors, mammary stem, c-kit, RANKL) and growth factor signaling in two independent cohorts (n = 1,188 and 2,334). Conclusions: Proliferation-related prognostic gene signatures can aid treatment decision-making for young women. However, breast cancer arising at a young age seems to be biologically distinct beyond subtype distribution. Separate therapeutic approaches such as targeting RANKL or mammary stem cells could therefore be needed. Clin Cancer Res; 18(5); 1341–51. ©2012 AACR.

Cancer Genomics: Technology, Discovery, and Translation

In recent years, the increasing awareness that somatic mutations and other genetic aberrations drive human malignancies has led us within reach of personalized cancer medicine (PCM). The implementation of PCM is based on the following premises: genetic aberrations exist in human malignancies; a subset of these aberrations drive oncogenesis and tumor biology; these aberrations are actionable (defined as having the potential to affect management recommendations based on diagnostic, prognostic, and/or predictive implications); and there are highly specific anticancer agents available that effectively modulate these targets. This article highlights the technology underlying cancer genomics and examines the early results of genome sequencing and the challenges met in the discovery of new genetic aberrations. Finally, drawing from experiences gained in a feasibility study of somatic mutation genotyping and targeted exome sequencing led by Princess Margaret Hospital-University Health Network and the Ontario Institute for Cancer Research, the processes, challenges, and issues involved in the translation of cancer genomics to the clinic are discussed.

Luminal-B breast cancer and novel therapeutic targets

Gene expression profiling has led to a new molecular classification of breast cancer characterized by four intrinsic subtypes: basal-like, HER2-positive, luminal A, and luminal B. Despite expressing estrogen receptor, the luminal-B subtype confers increased risk of early relapse with endocrine therapy compared with the luminal-A subtype. Although luminal-B definitions vary, the hallmark appears to be increased expression of proliferation-related genes. Several biological pathways are identified as possible contributors to the poor outcomes, and novel agents targeting these pathways are being developed with aims to improve survival. We review the definition of luminal-B breast cancer, its pathological and clinical features, and potential targets for treatment.

Patterns of Relapse in Patients With Clinical Stage I Testicular Cancer Managed With Active Surveillance

PURPOSE To evaluate the performance of active surveillance as a management strategy in broad populations and to inform the development of surveillance schedules by individual patient data regarding timing and type of relapse. METHODS Retrospective study including data from 2,483 clinical stage I (CSI) patients, 1,139 CSI nonseminoma and 1,344 CSI seminoma managed with active surveillance, with the majority treated between 1998 and 2010. Clinical outcomes including relapse and death, time distribution, extent of relapse and method of relapse detection observed on active surveillance were recorded. RESULTS Relapse occurred in 221 (19%) CSI-nonseminoma and 173 (13%) CSI-seminoma patients. Median time to relapse was 4 months (range, 2-61 months), 8 months (range, 2-77 months) and 14 months (range, 2-84 months) for lymphovascular invasion-positive CSI nonseminoma, lymphovascular invasion-negative CSI nonseminoma and CSI seminoma. Most relapses were observed within the first 2 years/3 years after orchiectomy for CSI nonseminoma (90%)/CSI seminoma (92%). Relapses were detected by computed tomography scan/tumor-markers in 87%/3% of seminoma recurrences, in 48%/38% of lymphovascular invasion-negative and 41%/61% of lymphovascular invasion-positive patients, respectively. 90% of CSI-nonseminoma and 99% of CSI-seminoma relapses exhibited International Germ Cell Collaborative Group good-risk features. Three patients with CSI nonseminoma died of disease (0.3%). One patient with CSI seminoma and two patients with CSI nonseminoma died because of treatment-related events. Overall, advanced disease was seen in both early- and late-relapse patients. All late recurrences were cured with standard therapy. Five-year disease-specific survival was 99.7% (95% CI, 99.24% to 99.93%). CONCLUSION Active surveillance for CSI testis cancer leads to excellent outcomes. The vast majority of relapses occur within 2 years of orchiectomy for CSI nonseminoma and within 3 years for CSI seminoma. Late and advanced stage relapse are rarely seen. These data may inform further refinement of rationally designed surveillance schedules.

Cardiac toxicity with anti-HER-2 therapies: what have we learned so far?

Trastuzumab, a monoclonal antibody that blocks HER-2 receptor, improves the survival of women with HER-2-positive early and advanced breast cancer when given with chemotherapy. Lapatinib, a dual tyrosine kinase inhibitor of EGFR and HER-2, is approved for the treatment of metastatic breast cancer patients after failure of prior anthracycline, taxanes and trastuzumab therapies in combination with capecitabine. Importantly, cardiac toxicity, manifested as symptomatic congestive heart failure or asymptomatic left ventricular ejection fraction decline, has been reported in some of the patients receiving these novel anti-HER-2 therapies, particularly when these drugs are used following anthracyclines, whose cardiotoxic potential has been recognized for decades. This review will focus on the incidence, natural history, underlying mechanisms, management, and areas of uncertainty regarding trastuzumab-and lapatinib-induced cardiotoxicity.

A Phase Ib Dose-Escalation Study of the Oral Pan-PI3K Inhibitor Buparlisib (BKM120) in Combination with the Oral MEK1/2 Inhibitor Trametinib (GSK1120212) in Patients with Selected Advanced Solid Tumors

Purpose: MAPK and PI3K/AKT/mTOR pathways play important roles in many tumors. In this study, safety, antitumor activity, and pharmacokinetics of buparlisib (pan class PI3K inhibitor) and trametinib (MEK inhibitor) were evaluated. Experimental Design: This open-label, dose-finding, phase Ib study comprised dose escalation, followed by expansion part in patients with RAS- or BRAF-mutant non–small cell lung, ovarian, or pancreatic cancer. Results: Of note, 113 patients were enrolled, 66 and 47 in dose-escalation and -expansion parts, respectively. MTD was established as buparlisib 70 mg + trametinib 1.5 mg daily [5/15, 33% patients with dose-limiting toxicities (DLT)] and recommended phase II dose (RP2D) buparlisib 60 mg + trametinib 1.5 mg daily (1/10, 10% patients with DLTs). DLTs included stomatitis (8/103, 8%), diarrhea, dysphagia, and creatine kinase (CK) increase (2/103, 2% each). Treatment-related grade 3/4 adverse events (AEs) occurred in 73 patients (65%); mainly CK increase, stomatitis, AST/ALT (aspartate aminotransferase/alanine aminotransferase) increase, and rash. For all (21) patients with ovarian cancer, overall response rate was 29% [1 complete response, 5 partial responses (PR)], disease control rate 76%, and median progression-free survival was 7 months. Minimal activity was observed in patients with non–small cell lung cancer (1/17 PR) and pancreatic cancer (best overall response was SD). Relative to historical data, buparlisib exposure increased and trametinib exposure slightly increased with the combination. Conclusions: At RP2D, buparlisib 60 mg + trametinib 1.5 mg daily shows promising antitumor activity for patients with KRAS-mutant ovarian cancer. Long-term tolerability of the combination at RP2D is challenging, due to frequent dose interruptions and reductions for toxicity. Clin Cancer Res; 21(4); 730–8. ©2014 AACR.

Feasibility of real time next generation sequencing of cancer genes linked to drug response: results from a clinical trial.

The successes of targeted drugs with companion predictive biomarkers and the technological advances in gene sequencing have generated enthusiasm for evaluating personalized cancer medicine strategies using genomic profiling. We assessed the feasibility of incorporating real‐time analysis of somatic mutations within exons of 19 genes into patient management. Blood, tumor biopsy and archived tumor samples were collected from 50 patients recruited from four cancer centers. Samples were analyzed using three technologies: targeted exon sequencing using Pacific Biosciences PacBio RS, multiplex somatic mutation genotyping using Sequenom MassARRAY and Sanger sequencing. An expert panel reviewed results prior to reporting to clinicians. A clinical laboratory verified actionable mutations. Fifty patients were recruited. Nineteen actionable mutations were identified in 16 (32%) patients. Across technologies, results were in agreement in 100% of biopsy specimens and 95% of archival specimens. Profiling results from paired archival/biopsy specimens were concordant in 30/34 (88%) patients. We demonstrated that the use of next generation sequencing for real‐time genomic profiling in advanced cancer patients is feasible. Additionally, actionable mutations identified in this study were relatively stable between archival and biopsy samples, implying that cancer mutations that are good predictors of drug response may remain constant across clinical stages.

Identification of a low-risk subgroup of HER-2-positive breast cancer by the 70-gene prognosis signature

Background:Overexpression of HER-2 is observed in 15–25% of breast cancers, and is associated with increased risk of recurrence. Current guidelines recommend trastuzumab and chemotherapy for most HER-2-positive patients. However, the majority of patients does not recur and might thus be overtreated with adjuvant systemic therapy. We investigated whether the 70-gene MammaPrint signature identifies HER-2-positive patients with favourable outcome.Methods:In all, 168 T1–3, N0–1, HER-2-positive patients were identified from a pooled database, classified by the 70-gene signature as good or poor prognosis, and correlated with long-term outcome. A total of 89 of these patients did not receive adjuvant chemotherapy.Results:In the group of 89 chemotherapy-naive patients, after a median follow-up of 7.4 years, 35 (39%) distant recurrences and 29 (33%) breast cancer-specific deaths occurred. The 70-gene signature classified 20 (22%) patients as good prognosis, with 10-year distant disease-free survival (DDFS) of 84%, compared with 69 (78%) poor prognosis patients with 10-year DDFS of 55%. The estimated hazard ratios (HRs) were 4.5 (95% confidence interval (CI) 1.1–18.7, P=0.04) and 3.8 (95% CI 0.9–15.8, P=0.07) for DDFS and breast cancer-specific survival (BCSS), respectively. In multivariate analysis adjusted for known prognostic factors and hormonal therapy, HRs were 5.8 (95% CI 1.3–26.7, P=0.03) and 4.7 (95% CI 1.0–21.7, P=0.05) for DDFS and BCSS, respectively.Interpretation:The 70-gene prognosis signature is an independent prognostic indicator that identifies a subgroup of HER-2-positive early breast cancer with a favourable long-term outcome.