Noura Choudhury

Afatinib Activity in Platinum-Refractory Metastatic Urothelial Carcinoma in Patients With ERBB Alterations

PURPOSE Somatic mutations and copy number variation in the ERBB family are frequent in urothelial carcinoma (UC) and may represent viable therapeutic targets. We studied whether afatinib (an oral, irreversible inhibitor of the ErbB family) has activity in UC and if specific ERBB molecular alterations are associated with clinical response. PATIENTS AND METHODS In this phase II trial, patients with metastatic platinum-refractory UC received afatinib 40 mg/day continuously until progression or intolerance. The primary end point was 3-month progression-free survival (PFS3). Prespecified tumor analysis for alterations in EGFR, HER2, ERBB3, and ERBB4 was conducted. RESULTS The first-stage enrollment goal of 23 patients was met. Patient demographic data included: 78% male, median age 67 years (range, 36 to 82 years), hemoglobin < 10 g/dL in 17%, liver metastases in 30%, median time from prior chemotherapy of 3.6 months, and Eastern Cooperative Oncology Group performance status ≤ 1 in 100%. No unexpected toxicities were observed; two patients required dose reduction for grade 3 fatigue and rash. Overall, five of 23 patients (21.7%) met PFS3 (two partial response, three stable disease). Notably, among the 21 tumors analyzed, five of six patients (83.3%) with HER2 and/or ERBB3 alterations achieved PFS3 (PFS = 10.3, 7.0, 6.9, 6.3, and 5.0 months, respectively) versus none of 15 patients without alterations (P < .001). Three of four patients with HER2 amplification and three of three patients with ERBB3 somatic mutations (G284R, V104M, and R103G) met PFS3. One patient with both HER2 amplification and ERBB3 mutation never progressed on therapy, but treatment was discontinued after 10.3 months as a result of depressed ejection fraction. The median time to progression/discontinuation was 6.6 months in patients with HER2/ERBB3 alterations versus 1.4 months in patients without alterations (P < .001). CONCLUSION Afatinib demonstrated significant activity in patients with platinum-refractory UC with HER2 or ERBB3 alterations. The potential contribution of ERBB3 to afatinib sensitivity is novel. Afatinib deserves further investigation in molecularly selected UC.

β-Catenin Is Required for the Tumorigenic Behavior of Triple-Negative Breast Cancer Cells

Our previous data illustrated that activation of the canonical Wnt signaling pathway was enriched in triple-negative breast cancer and associated with reduced overall survival in all patients. To determine whether Wnt signaling may be a promising therapeutic target for triple-negative breast cancer, we investigated whether β-catenin was necessary for tumorigenic behaviors in vivo and in vitro. β-catenin expression level was significantly reduced in two human triple-negative breast cancer cell lines, MDA-MB-231 and HCC38, using lentiviral delivery of β-catenin-specific small hairpin RNAs (shRNAs). Upon implantation of the cells in the mammary fat pad of immunocompromised mice, we found that β-catenin shRNA HCC38 cells formed markedly smaller tumors than control cells and grew much more slowly. In in vitro assays, β-catenin silencing significantly reduced the percentage of Aldefluor-positive cells, a read-out of the stem-like cell population, as well as the expression of stem cell-related target genes including Bmi-1 and c-Myc. β-catenin-knockdown cells were also significantly impaired in their ability to migrate in wound-filling assays and form anchorage-independent colonies in soft agar. β-catenin-knockdown cells were more sensitive to chemotherapeutic agents doxorubicin and cisplatin. Collectively, these data suggest that β-catenin is required for triple-negative breast cancer development by controlling numerous tumor-associated properties, such as migration, stemness, anchorage-independent growth and chemosensitivity.

Low T-cell Receptor Diversity, High Somatic Mutation Burden, and High Neoantigen Load as Predictors of Clinical Outcome in Muscle-invasive Bladder Cancer

BACKGROUND The success of cancer immunotherapies has highlighted the potent ability of local adaptive immune responses to eradicate cancer cells by targeting neoantigens generated by somatic alterations. However, how these factors interact to drive the natural history of muscle-invasive bladder cancer (MIBC) is not well understood. OBJECTIVE To investigate the role of immune regulation in MIBC disease progression, we performed massively parallel T-cell receptor (TCR) sequencing of tumor-infiltrating T cells (TILs), in silico neoantigen prediction from exome sequences, and expression analysis of immune-related genes. DESIGN, SETTING, AND PARTICIPANTS We analyzed 38 MIBC tissues from patients who underwent definitive surgery with a minimum clinical follow-up of 2 yr. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Recurrence-free survival (RFS) was determined. TCR diversity was quantified using Simpsons diversity index. The main analyses involved the Mann-Whitney U test, Kaplan-Meier survival analysis, and Cox proportional hazards models. RESULTS AND LIMITATIONS Low TCRβ chain diversity, correlating with oligoclonal TIL expansion, was significantly correlated with longer RFS, even after adjustment for pathologic tumor stage, node status, and receipt of adjuvant chemotherapy (hazard ratio 2.67, 95% confidence interval 1.08-6.60; p=0.03). Patients with both a high number of neoantigens and low TCRβ diversity had longer RFS compared to those with fewer neoantigens and high TCR diversity (median RFS 275 vs 30 wk; p=0.03). Higher expression of immune cytolytic genes was associated with nonrecurrence among patients with low TCR diversity or fewer neoantigens. Limitations include the sample size and the inability to distinguish CD8+ and CD4+ T cells using TCR sequencing. CONCLUSIONS These findings are the first to show that detailed tumor immune-genome analysis at definitive surgery can identify molecular patterns of antitumor immune response contributing to better clinical outcomes in MIBC. PATIENT SUMMARY We discovered that clonal expansion of certain T cells in tumor tissue, possibly targeting cancer-specific antigens, contributes to prevention of bladder cancer recurrence.

Establishment of CYP2D6 reference samples by multiple validated genotyping platforms.

Cytochrome P450 2D6 (cytochrome P450, family 2, subfamily D, polypeptide 6 (CYP2D6)), a highly polymorphic drug-metabolizing enzyme, is involved in the metabolism of one-quarter of the most commonly prescribed medications. Here we have applied multiple genotyping methods and Sanger sequencing to assign precise and reproducible CYP2D6 genotypes, including copy numbers, for 48 HapMap samples. Furthermore, by analyzing a set of 50 human liver microsomes using endoxifen formation from N-desmethyl-tamoxifen as the phenotype of interest, we observed a significant positive correlation between CYP2D6 genotype-assigned activity score and endoxifen formation rate (rs=0.68 by rank correlation test, P=5.3 × 10−8), which corroborated the genotype–phenotype prediction derived from our genotyping methodologies. In the future, these 48 publicly available HapMap samples characterized by multiple substantiated CYP2D6 genotyping platforms could serve as a reference resource for assay development, validation, quality control and proficiency testing for other CYP2D6 genotyping projects and for programs pursuing clinical pharmacogenomic testing implementation.

Importance of immunopharmacogenomics in cancer treatment: Patient selection and monitoring for immune checkpoint antibodies

In the last 5 years, immune checkpoint antibodies have become established as anticancer agents for various types of cancer. These antibody drugs, namely cytotoxic T‐lymphocyte‐associated antigen, programmed death‐1, and programmed death ligand‐1 antibodies, have revealed relatively high response rates, the ability to induce durable responses, and clinical efficacy in malignancies not previously thought to be susceptible to immune‐based strategies. However, because of its unique mechanisms of activating the host immune system against cancer as well as expensive cost, immune checkpoint blockade faces novel challenges in selecting appropriate patient populations, monitoring clinical responses, and predicting immune adverse events. The development of objective criteria for selecting patient populations that are likely to have benefit from these therapies has been vigorously investigated but still remains unclear. In this review, we describe immune checkpoint inhibition‐specific challenges with patient selection and monitoring, and focus on approaches to remedy these challenges. We also discuss applications of the emerging field of immunopharmacogenomics for guiding selection and monitoring for anti‐immune checkpoint treatment.

WT1 peptide vaccine in Montanide in contrast to poly ICLC, is able to induce WT1-specific immune response with TCR clonal enrichment in myeloid leukemia

BackgroundThe optimal strategy for vaccination to induce CD8+ T cell responses against WT1 is not known.MethodsA pilot randomized study in HLA-A02+ patients to receive vaccination with WT1 in Montanide or in poly ICLC, a TLR3 agonist, to explore the novel immune adjuvant was conducted. Seven patients were randomized. Four patients received WT1 in Montanide, and three with WT1 in poly ICLC. Five patients were in morphologic remission and two had residual morphologic disease at the study entry.ResultsAll patients finished the induction phase without any major toxicity except mild transient local injection reaction. One patient on the Montanide arm developed aseptic ulceration at two vaccine sites which healed without antibiotics. Three of 4 patients on the Montanide arm had a decreased expression of WT1 after WT1 vaccination, and two of them demonstrated generation of WT1-specific cytotoxic CD8+ T cell responses with biased TCR beta chain enrichment. In contrast, no obvious WT1-specific immune responses were detected in two patients on the poly ICLC arm, nor was there clonal enrichment by TCR alpha/beta sequencing; however, these patients did also have decreased WT1 expression and remained in remission several years after the initiation of treatment.ConclusionsWT1 peptide vaccine with Montanide as an adjuvant induces detectable WT1-specific CD8+ T cell responses with clonal TCR enrichment, which may be capable of controlling leukemia recurrence in the setting of minimal residual disease. Poly ICLC may induce anti-leukemic activity in the absence of detectable WT1 specific CD8+ T cell responses.Trial registration NCT01842139, 7/3/2012 retrospectively registered; https://clinicaltrials.gov/ct2/show/NCT01842139.

Patient Selection and Monitoring for Immunotherapies: Challenges for Immune Checkpoint Antibody and Cell Therapies

In the past 10 years, immunotherapies with immune checkpoint antibodies alone or in combination with other treatment modalities have become established as promising anticancer agents across a wide range of malignancies and have even demonstrated clinical effect in solid malignancies that were previously not thought to be susceptible to immune-based strategies. However, because of the high cost of applying these therapies, frequent observation of immune-related adverse events, and deviation from conventional tumor-response criteria, immunotherapies present novel challenges in appropriate patient selection and monitoring for the disease and immunological responses. In the age of personalized or precision medicine, clinicians, pharmaceutical companies, and translational researchers have united in the objective to develop criteria that would target a patient population most likely to benefit from these therapies in the face of potential toxicities. In this chapter, I focus on approaches for patient selection and monitoring in immune checkpoint antibody therapy, namely anticytotoxic T-lymphocyte-associated antigen (CTLA-4) antibodies and anti-programmed death-1 (PD-1) or programmed death ligand-1 (PD-L1) antibodies. Briefly, I also discuss these principles in adoptive T cell therapies.

Abstract 499: {beta}-catenin is required for triple-negative breast tumorigenesis.

Triple-negative breast cancer is associated with a poor prognosis and high frequency of recurrence, but because the molecular drivers of these tumors are not well understood, they lack any targeted therapies. Our previous data illustrated that activation of the canonical Wnt signaling pathway, as assessed by nuclear and cytosolic accumulation of β-catenin, was enriched in triple-negative breast cancer and associated with reduced overall survival in all patients. To investigate whether Wnt signaling may be a promising therapeutic target for triple-negative breast cancer, we silenced β-catenin expression stably in MDA-MB-231 and HCC38 triple-negative breast cancer cells using lentiviral delivery of β-catenin-specific small hairpin RNAs (shRNAs). Upon implantation of the cells in the mammary fat pad of immunocompromised mice, we found that β-catenin shRNA HCC38 cells formed markedly smaller tumors than parental or scrambled shRNA control cells, and the tumors had slower growth rates. In vitro, β-catenin silencing significantly reduced the percentage of Aldefluor-positive cells, a read-out of the stem-like cell population, as well as the expression of stem cell-related target genes including Bmi-1 and c-Myc. β-catenin-knockdown cells were also significantly impaired in their ability to migrate in wound-filling assays and form anchorage-independent colonies in soft agar. To address the contribution of the signaling pool of β-catenin to these phenotypes, the parental cells were treated with a Wnt pathway inhibitor, ICG-001, that blocks the interaction of β-catenin with the CBP transcriptional co-activator. In contrast to β-catenin depletion, ICG-001 treatment did not inhibit tumor cell migration but did significantly suppress proliferation, suggesting that at least some of the oncogenic functions of β-catenin may not be due to its transcriptional activity. We next addressed the influence of Wnt signaling on the therapeutic response of triple-negative breast cancer cells and found, surprisingly, that β-catenin-knockdown cells were more resistant to several therapeutic agents, including cisplatin, doxorubicin and paclitaxel. ICG-001 treatment also conferred resistance of HCC38 cells to cisplatin and doxorubicin, supporting the involvement of β-catenin-mediated transcription in this effect. Collectively, these data suggest that β-catenin is required for triple-negative breast cancer development by controlling numerous tumor-associated properties, such as migration, stemness and anchorage-independent growth, by mechanisms that may extend beyond β-catenin-mediated transcription control. These findings also highlight the need to more completely dissect pathways implicated in driving triple-negative breast cancer not only so that they can be exploited as therapeutic targets, but also so their roles in modulating chemotherapeutic responses can be appreciated. Citation Format: Jinhua Xu, Jenifer R. Prosperi, Noura Choudhury, Kathleen H. Goss. β-catenin is required for triple-negative breast tumorigenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 499. doi:10.1158/1538-7445.AM2013-499