Adaptive Randomization of Veliparib-Carboplatin Treatment in Breast Cancer

Phase I/Ib study of olaparib and carboplatin in women with triple negative breast cancer

PURPOSE

To investigate the safety, activity, and potential biomarkers of response to olaparib and carboplatin combination in sporadic triple negative breast cancer (TNBC). EXPERIMENTAL DESIGN: Metastatic or recurrent TNBC patients with no germline BRCA mutation or with BRCAPro scores <10% and a negative family history were eligible. A 3+3 dose escalation tested olaparib capsules (400mg bid, days1-7) with carboplatin AUC3-5 on day1 or 2 every 21 days, ≤ 8 cycles, with olaparib 400mg bid maintenance. Peripheral blood mononuclear cells were collected for polymorphisms and PAR levels, and paired tumor biopsies (pre-/post-cycle 1) for proteomics and apoptosis endpoints.

RESULTS

28 women were treated (median 5 prior regimens [0-12]). Dose-limiting toxicity was thrombocytopenia, and symptomatic hyponatremia with carboplatin AUC5. The maximum tolerated dose was olaparib 400mg bid+carboplatin AUC4. Grade 3 and 4 adverse events included neutropenia (36%), thrombocytopenia (11%), and anemia (11%). Responses included 1 complete response (CR; 69⁺months) and 5/27 partial responses (19%; median 4months [4-7]), for a response rate of 22%. Biomarker findings did not correlate with response. The long-term CR patient with prior negative BRCA testing was found to have deletion of BRCA1 exons1-2.

CONCLUSIONS

The olaparib/carboplatin combination is tolerable and has modest activity in sporadic TNBC patients. Further evaluation of predictive biomarkers to identify those with BRCA wild type who had response is warranted.

Sigma-2 ligands and PARP inhibitors synergistically trigger cell death in breast cancer cells

The sigma-2 receptor is overexpressed in proliferating cells compared to quiescent cells and has been used as a target for imaging solid tumors by positron emission tomography. Recent work has suggested that the sigma-2 receptor may also be an effective therapeutic target for cancer therapy. Poly (ADP-ribose) polymerase (PARP) is a family of enzymes involved in DNA damage response. In this study, we looked for potential synergy of cytotoxicity between PARP inhibitors and sigma-2 receptor ligands in breast cancer cell lines. We showed that the PARP inhibitor, YUN3-6, sensitized mouse breast cancer cell line, EMT6, to sigma-2 receptor ligand (SV119, WC-26, and RHM-138) induced cell death determined by cell viability assay and colony forming assay. The PARP inhibitor, olaparib, sensitized tumor cells to a different sigma-2 receptor ligand SW43-induced apoptosis and cell death in human triple negative cell line, MDA-MB-231. Olaparib inhibited PARP activity and cell proliferation, and arrested cells in G2/M phase of the cell cycle in MDA-MB-231 cells. Subsequently cells became sensitized to SW43 induced cell death. In conclusion, the combination of sigma-2 receptor ligands and PARP inhibitors appears to hold promise for synergistically triggering cell death in certain types of breast cancer cells and merits further investigation.

Low Recombination Proficiency Score (RPS) Predicts Heightened Sensitivity to DNA-Damaging Chemotherapy in Breast Cancer

Purpose: Molecular-based cancer tests have been developed to augment the standard clinical and pathologic features used to tailor treatments to individual breast cancer patients. Homologous recombination (HR) repairs double-stranded DNA breaks and promotes tolerance to lesions that disrupt DNA replication. Recombination Proficiency Score (RPS) quantifies HR efficiency based on the expression of four genes involved in DNA damage repair. We hypothesized low RPS values can identify HR-deficient breast cancers most sensitive to DNA-damaging chemotherapy.Experimental Design: We collected pathologic tumor responses and tumor gene expression values for breast cancer patients that were prospectively enrolled on clinical trials involving preoperative chemotherapy followed by surgery (N = 513). We developed an algorithm to calculate breast cancer-specific RPS (RPS_b) values on an individual sample basis.Results: Low RPS_b tumors are approximately twice as likely to exhibit a complete pathologic response or minimal residual disease to preoperative anthracycline-based chemotherapy as compared with high RPS_b tumors. Basal, HER2-enriched, and luminal B breast cancer subtypes exhibit low RPS_b values. In addition, RPS_b predicts treatment responsiveness after controlling for clinical and pathologic features, as well as intrinsic breast subtype.Conclusions: Overall, our findings indicate that low RPS breast cancers exhibit aggressive features at baseline, but they have heightened sensitivity to DNA-damaging chemotherapy. Low RPS_b values in basal, HER2-enriched, and luminal B subtypes provide a mechanistic explanation for their clinical behaviors and genomic instability. RPS_b augments standard clinical and pathologic features used to tailor treatments, thereby enabling more personalized treatment strategies for individual breast cancer patients. Clin Cancer Res; 23(15); 4493-500. ©2017 AACR.

Efficacy and Safety of Anti-Trop-2 Antibody Drug Conjugate Sacituzumab Govitecan (IMMU-132) in Heavily Pretreated Patients With Metastatic Triple-Negative Breast Cancer

Purpose Trop-2, expressed in most triple-negative breast cancers (TNBCs), may be a potential target for antibody-drug conjugates. Sacituzumab govitecan, an antibody-drug conjugate, targets Trop-2 for the selective delivery of SN-38, the active metabolite of irinotecan. Patients and Methods We evaluated sacituzumab govitecan in a single-arm, multicenter trial in patients with relapsed/refractory metastatic TNBC who received a 10 mg/kg starting dose on days 1 and 8 of 21-day repeated cycles. The primary end points were safety and objective response rate; secondary end points were progression-free survival and overall survival. Results In 69 patients who received a median of five prior therapies (range, one to 12) since diagnosis, the confirmed objective response rate was 30% (partial response, n = 19; complete response, n = 2), the median response duration was 8.9 (95% CI, 6.1 to 11.3) months, and the clinical benefit rate (complete response + partial response + stable disease ≥ 6 months) was 46%. These responses occurred early, with a median onset of 1.9 months. Median progression-free survival was 6.0 (95% CI, 5.0 to 7.3) months, and median overall survival was 16.6 (95% CI, 11.1 to 20.6) months. Grade ≥ 3 adverse events included neutropenia (39%), leukopenia (16%), anemia (14%), and diarrhea (13%); the incidence of febrile neutropenia was 7%. The majority of archival tumor specimens (88%) were moderately to strongly positive for Trop-2 by immunohistochemistry. No neutralizing antibodies to the ADC or antibody were detected, despite repeated cycles developed. Conclusion Sacituzumab govitecan was well tolerated and induced early and durable responses in heavily pretreated patients with metastatic TNBC. As a therapeutic target and predictive biomarker, Trop-2 warrants further research.

Clinical Trial Characteristics and Barriers to Participant Accrual: The MD Anderson Cancer Center Experience over 30 years, a Historical Foundation for Trial Improvement

Purpose: Slow-accruing clinical trials delay the translation of basic biomedical research, contribute to increasing health care costs, and may prohibit trials from reaching their original goals.Experimental Design: We analyzed a prospectively maintained institutional database that tracks all clinical studies at the MD Anderson Cancer Center (Houston, TX). Inclusion criteria were activated phase I-III trials, maximum projected accrual ≥10 participants, and activation prior to March 25, 2011. The primary outcome was slow accrual, defined as <2 participants per year. Correlations of trial characteristics with slow accrual were assessed with logistic regression.Results: A total of 4,269 clinical trials met inclusion criteria. Trials were activated between January 5, 1981, and March 25, 2011, with a total of 145,214 participants enrolled. Median total enrolment was 16 [interquartile range (IQR), 5-34], with an average enrolment rate of 8.7 participants per year (IQR, 3.3-17.7). There were 755 (18%) trials classified as slow accruing. On multivariable analysis, slow accrual exhibited robust associations with national cooperative group trials (OR = 4.16, P < 0.0001 vs. industry sponsored), time from trial activation to first enrolment (OR = 1.13 per month, P < 0.0001), and maximum targeted accrual (OR = 0.16 per log10 increase, P < 0.0001). Recursive partitioning analysis identified trials requiring more than 70 days (2.3 months) between activation and first participant enrolment as having higher odds of slow accrual (23% vs. 5%, OR = 5.56, P < 0.0001).Conclusions: We identified factors associated with slow trial accrual. Given the lack of data on clinical trials at the institutional level, these data will help build a foundation from which targeted initiatives may be developed to improve the clinical trial enterprise. Clin Cancer Res; 23(6); 1414-21. ©2017 AACR.

The Role of Carboplatin in the Neoadjuvant Chemotherapy Treatment of Triple Negative Breast Cancer

Triple negative breast (TNBC) cancer constitutes a heterogeneous group of disease with histologic and molecular differences. Complete pathologic response to neoadjuvant chemotherapy (NACT) in TNBC is associated with improved outcomes. Efforts have been made in identifying drug combinations that will increase the response rate to preoperative chemotherapy. In this review we present recent studies that have incorporated carboplatin (Cb) in the NACT of TNBC. We discuss the homologous recombination deficiency score and the somatic or germline mutation for BRCA as potential biomarkers for future selection of patients that could benefit from the addition of Cb to NACT.

Adaptive Designs for Non-inferiority Trials with Multiple Experimental Treatments

The increase in the popularity of non-inferiority clinical trials represents the increasing need to search for substitutes for some reference (standard) treatments. A new treatment would be preferred to the standard treatment if the benefits of adopting it outweigh a possible clinically insignificant reduction in treatment efficacy (non-inferiority margin). Statistical procedures have recently been developed for treatment comparisons in non-inferiority clinical trials that have multiple experimental (new) treatments. An ethical concern for non-inferiority trials is that some patients undergo the less effective treatments; this problem is more serious when multiple experimental treatments are included in a balanced trial in which the sample sizes are the same for all experimental treatments. With the aim of giving fewer patients the inferior treatments, we propose a response-adaptive treatment allocation scheme that is based on the doubly adaptive biased coin design. The proposed adaptive design is also shown to be superior to the balanced design in terms of testing power.

Biological Subtypes of Triple-Negative Breast Cancer

Triple-negative breast cancers (TNBCs) are defined as tumors that are negative for estrogen, progesterone and HER-2 receptor. At a percentage of 10-20% TNBCs represent a minority in all breast cancers. However, because of the poor prognosis this particular subtype, triple negative disease accounts for a disproportionate number of metastatic cases and breast cancer deaths. Identification of its subtypes is essential for understanding the biological characteristics and clinical behavior of TNBC, as well as for developing personalized treatments. This review will focus on the great progress that has been made in the past few years on identifying new targets in TNBC subtypes and a variety of new treatment options that are on the verge of routine clinical application.

Precision surgery and avoiding over-treatment

Over-diagnosis and over-treatment are consequences of greater awareness about breast cancer, more intensive screening, and the resultant identification of more cases of breast cancer that are low or ultralow risk. This area represents an important opportunity to optimize the delivery of appropriate targeted therapy for breast cancer patients. Despite the evolution of breast cancer care over the last few decades and our ability to tailor treatment to biology, a one-size fits all approach is still prevalent in the local and regional management of and screening for breast cancer, failing to reflect the unique biology and tumor characteristics of each patient. In this review, we explore how we can use new tools to better define tumor biology and also how we can change current clinical practices based on already available data. Every surgeon should be knowledgeable about how to craft personalized breast cancer care in the areas of systemic therapy, adjuvant radiation therapy, management of ductal carcinoma in situ (DCIS), precision surgery, and breast cancer screening.

PARP Inhibitors in Reproductive System Cancers: Current Use and Developments

The repair of DNA damage is a critical cellular process governed by multiple biochemical pathways that are often found to be defective in cancer cells. The poly(ADP-ribose) polymerase (PARP) family of proteins controls response to single-strand DNA breaks by detecting these damaged sites and recruiting the proper factors for repair. Blocking this pathway forces cells to utilize complementary mechanisms to repair DNA damage. While PARP inhibition may not, in itself, be sufficient to cause tumor cell death, inhibition of DNA repair with PARP inhibitors is an effective cytotoxic strategy when it is used in patients who carry other defective DNA-repair mechanisms, such as mutations in the genes BRCA 1 and 2. This discovery has supported the development of PARP inhibitors (PARPi), agents that have proven effective against various types of tumors that carry BRCA mutations. With the application of next-generation sequencing of tumors, there is increased interest in looking beyond BRCA mutations to identify genetic and epigenetic aberrations that might lead to similar defects in DNA repair, conferring susceptibility to PARP inhibition. Identification of these genetic lesions and the development of screening assays for their detection may allow for the selection of patients most likely to respond to this class of anticancer agents. This article provides an overview of clinical trial results obtained with PARPi and describes the companion diagnostic assays being established for patient selection. In addition, we review known mechanisms for resistance to PARPi and potential strategies for combining these agents with other types of therapy.

Exploratory trials in mental health: anything to learn from other disciplines?

OBJECTIVE

Confirmatory randomised controlled trials require solid justifications, especially with regard to whether the experimental intervention is promising. Such evidence is generated in exploratory trials. However, empirical evidence shows that the quality of such trials is still suboptimal. More generally, the development process of healthcare interventions and especially of drugs, remains inefficient. Over the past 10-20 years, a vast amount of methodological work has been published about exploratory trials. This overview introduces some of the concepts and recent developments in the field.

METHODS

A narrative approach was taken for this overview. This article focuses on study designs developed outside the mental health field to introduce concepts that might not be familiar to clinical researchers in psychiatry and psychology. Non-randomised and randomised exploratory trial designs are covered. The article ends with a brief discussion on pilot studies and their difference to exploratory studies.

RESULTS

Classical designs for exploratory trials such as Simon's two-stage design still have a role. However, randomised exploratory trials are probably more suitable for mental health interventions. Newer, more flexible designs such as multistage, multiarm trials or platform trials have the potential to improve the efficiency of exploratory and subsequently confirmatory experiments.

CONCLUSIONS

Although often not directly applicable, borrowing (study) design ideas from other medical disciplines has the potential to improve exploratory trials in the mental health field. At the same time, more explicit use of study designs specifically designed for exploratory trials will help to improve the transparency of such trials.

Innovations in Clinical Trial Design in the Era of Molecular Profiling

Historically, cancer has been studied, and therapeutic agents have been evaluated based on organ site, clinical staging, and histology. The science of molecular profiling has expanded our knowledge of cancer at the cellular and molecular level such that numerous subtypes are being described based on biomarker expression and genetic mutations rather than traditional classifications of the disease. Drug development has experienced a concomitant revolution in response to this knowledge with many new targeted therapeutic agents becoming available, and this has necessitated an evolution in clinical trial design. The traditional, large phase II and phase III adjuvant trial models need to be replaced with smaller, shorter, and more focused trials. These trials need to be more efficient and adaptive in order to quickly assess the efficacy of new agents and develop new companion diagnostics. We are now seeing a substantial shift from the traditional multiphase trial model to an increase in phase II adjuvant and neoadjuvant trials in earlier-stage disease incorporating surrogate endpoints for long-term survival to assess efficacy of therapeutic agents in shorter time frames. New trial designs have emerged with capabilities to assess more efficiently multiple disease types, multiple molecular subtypes, and multiple agents simultaneously, and regulatory agencies have responded by outlining new pathways for accelerated drug approval that can help bring effective targeted therapeutic agents to the clinic more quickly for patients in need.

PIPELINEs: Creating Comparable Clinical Knowledge Efficiently by Linking Trial Platforms

Adaptive, seamless, multisponsor, multitherapy clinical trial designs executed as large scale platforms, could create superior evidence more efficiently than single-sponsor, single-drug trials. These trial PIPELINEs also could diminish barriers to trial participation, increase the representation of real-world populations, and create systematic evidence development for learning throughout a therapeutic life cycle, to continually refine its use. Comparable evidence could arise from multiarm design, shared comparator arms, and standardized endpoints-aiding sponsors in demonstrating the distinct value of their innovative medicines; facilitating providers and patients in selecting the most appropriate treatments; assisting regulators in efficacy and safety determinations; helping payers make coverage and reimbursement decisions; and spurring scientists with translational insights. Reduced trial times and costs could enable more indications, reduced development cycle times, and improved system financial sustainability. Challenges to overcome range from statistical to operational to collaborative governance and data exchange.

Approaches to modernize the combination drug development paradigm

Recent advances in genomic sequencing and omics-based capabilities are uncovering tremendous therapeutic opportunities and rapidly transforming the field of cancer medicine. Molecularly targeted agents aim to exploit key tumor-specific vulnerabilities such as oncogenic or non-oncogenic addiction and synthetic lethality. Additionally, immunotherapies targeting the host immune system are proving to be another promising and complementary approach. Owing to substantial tumor genomic and immunologic complexities, combination strategies are likely to be required to adequately disrupt intricate molecular interactions and provide meaningful long-term benefit to patients. To optimize the therapeutic success and application of combination therapies, systematic scientific discovery will need to be coupled with novel and efficient clinical trial approaches. Indeed, a paradigm shift is required to drive precision medicine forward, from the traditional "drug-centric" model of clinical development in pursuit of small incremental benefits in large heterogeneous groups of patients, to a "strategy-centric" model to provide customized transformative treatments in molecularly stratified subsets of patients or even in individual patients. Crucially, to combat the numerous challenges facing combination drug development-including our growing but incomplete understanding of tumor biology, technical and informatics limitations, and escalating financial costs-aligned goals and multidisciplinary collaboration are imperative to collectively harness knowledge and fuel continual innovation.

A randomized Phase II study of veliparib with temozolomide or carboplatin/paclitaxel versus placebo with carboplatin/paclitaxel in BRCA1/2 metastatic breast cancer: design and rationale

Veliparib is an orally administered poly(ADP-ribose) polymerase inhibitor that is being studied in Phase I–III clinical trials, including Phase III studies in non-small-cell lung cancer, ovarian cancer and breast cancer. Tumor cells with deleterious BRCA1 or BRCA2 mutations are deficient in homologous recombination DNA repair and are intrinsically sensitive to platinum therapy and poly(ADP-ribose) polymerase inhibitors. We describe herein the design and rationale of a Phase II trial investigating whether the addition of veliparib to temozolomide or carboplatin/paclitaxel provides clinical benefit over carboplatin/paclitaxel with placebo in patients with locally recurrent or metastatic breast cancer harboring a deleterious BRCA1 or BRCA2 germline mutation (Trial registration: EudraCT 2011-002913-12, NCT01506609).

Adaptive Randomization of Neratinib in Early Breast Cancer

BACKGROUND

The heterogeneity of breast cancer makes identifying effective therapies challenging. The I-SPY 2 trial, a multicenter, adaptive phase 2 trial of neoadjuvant therapy for high-risk clinical stage II or III breast cancer, evaluated multiple new agents added to standard chemotherapy to assess the effects on rates of pathological complete response (i.e., absence of residual cancer in the breast or lymph nodes at the time of surgery).

METHODS

We used adaptive randomization to compare standard neoadjuvant chemotherapy plus the tyrosine kinase inhibitor neratinib with control. Eligible women were categorized according to eight biomarker subtypes on the basis of human epidermal growth factor receptor 2 (HER2) status, hormone-receptor status, and risk according to a 70-gene profile. Neratinib was evaluated against control with regard to 10 biomarker signatures (prospectively defined combinations of subtypes). The primary end point was pathological complete response. Volume changes on serial magnetic resonance imaging were used to assess the likelihood of such a response in each patient. Adaptive assignment to experimental groups within each disease subtype was based on Bayesian probabilities of the superiority of the treatment over control. Enrollment in the experimental group was stopped when the 85% Bayesian predictive probability of success in a confirmatory phase 3 trial of neoadjuvant therapy reached a prespecified threshold for any biomarker signature ("graduation"). Enrollment was stopped for futility if the probability fell to below 10% for every biomarker signature.

RESULTS

Neratinib reached the prespecified efficacy threshold with regard to the HER2-positive, hormone-receptor-negative signature. Among patients with HER2-positive, hormone-receptor-negative cancer, the mean estimated rate of pathological complete response was 56% (95% Bayesian probability interval [PI], 37 to 73%) among 115 patients in the neratinib group, as compared with 33% among 78 controls (95% PI, 11 to 54%). The final predictive probability of success in phase 3 testing was 79%.

CONCLUSIONS

Neratinib added to standard therapy was highly likely to result in higher rates of pathological complete response than standard chemotherapy with trastuzumab among patients with HER2-positive, hormone-receptor-negative breast cancer. (Funded by QuantumLeap Healthcare Collaborative and others; I-SPY 2 TRIAL ClinicalTrials.gov number, NCT01042379.).

Review of Triple Negative Breast Cancer and the Impact of Inducible Nitric Oxide Synthase on Tumor Biology and Patient Outcomes

Triple negative breast cancers (TNBCs), which are defined as estrogen-receptor, progesterone-receptor, and HER2-receptor negative, account for 10-20% of breast cancers, and they are associated with early metastasis, chemotherapeutic resistance, and poor survival rates. One aspect of TNBC that complicates its prognosis and the development of new molecular therapeutic targets is its clinical and molecular heterogeneity. Herein we compare TNBC and basal cytokeratin-positive breast cancers. We examine the different TNBC molecular subtypes, based on gene expression profiling, which include basal-like, mesenchymal, and luminal androgen receptors, in the context of their biology and impact on TNBC prognosis. We explore the potential role of inducible nitric oxide synthase (iNOS) in TNBC tumor biology and treatment responses. iNOS has been shown to induce p53 mutation accumulation, basal-like gene signature enrichment, and transactivation of the epidermal growth factor receptor (EGFR) via S-nitrosylation, all of which are key components of TNBC biology. Moreover, iNOS predicts poor outcome in TNBC, and iNOS inhibitors show efficacy against TNBC when used in combination with chemotherapy. We discuss molecular targeted approaches, including EGFR, PARP, and VEGF inhibitors and immunotherapeutics, that are under consideration for the treatment of TNBC and what role, if any, iNOS may play in their success.