Adaptive Randomization of Veliparib-Carboplatin Treatment in Breast Cancer

Role of Platinum in Early-Stage Triple-Negative Breast Cancer

OPINION STATEMENT

Triple-negative breast cancer (TNBC) is both a clinically and genomically heterogeneous disease, with distinct molecular subtypes; however, most epidemiologic and clinical studies to date have defined it under a "one disease" umbrella. This is an important point, since one therapeutic approach for all TNBCs is unlikely to be successful given the underlying biological diversity. In this review, we explore the role of platinums in the treatment of TNBC, as well as the potential for biomarkers to predict patient response to these agents. The results of neoadjuvant TNBC trials, with addition of platinum to anthracycline/taxane-based chemotherapies, have been very encouraging given increases in pathologic complete response (pCR) rates. However, we do not have any evidence yet that these agents would lead to improvement in disease-free and overall survival. Moreover, addition of platinums increases toxicity and can compromise current standard chemotherapy doses, which further impedes their use in all TNBC patients. Therefore, the addition of platinums to standard chemotherapy should be used with caution and in discussion with patients after a careful assessment of risks and benefits. Clinical trials addressing the role of platinums in TNBC further remain of significant value.

Practical Approach to Triple-Negative Breast Cancer

Triple negative is a term applied to breast cancers that do not meaningfully express the estrogen or progesterone hormone receptors or overexpress the human epidermal growth factor receptor 2 tyrosine kinase. At present, the only proven method for systemic management of triple-negative breast cancer for both early-stage and metastatic settings is cytotoxic chemotherapy. Here, we provide a comprehensive review of management strategies that are best supported by available data. We also review recent advances most likely to affect treatment of triple-negative breast cancer in the coming years with particular emphasis on targeted agents, biologics, and immunotherapy.

Triple-negative breast cancer and the potential for targeted therapy

Breast cancer is composed of several well-recognized subtypes including estrogen receptor, progesterone receptor and HER2 triple-negative breast cancer (TNBC). Without available targeted therapy options, standard of care for TNBC remains chemotherapy. It is of interest to note that TNBC tumors generally have better responses to chemotherapy compared with other subtypes. However, patients without complete response account for approximately 80% of TNBC. Mounting evidence suggests significant heterogeneity within the TNBC subtype, and studies have focused on genetic targets with high rates of altered expression. Recent studies suggest clear possibilities for benefits from targeted therapy in TNBC. In this review, we summarize studies of targeted therapy, including within mouse models, and discuss their applications in the development of combinatorial treatments to treat TNBC.

Molecular Pathways: Targeting the Microenvironment of Liver Metastases

Curative treatment for metastatic solid cancers remains elusive. The liver, which is nourished by a rich blood supply from both the arterial and portal venous systems, is the most common site of visceral metastases, particularly from cancers arising in the gastrointestinal tract, with colorectal cancer being the predominant primary site in Western countries. A mounting body of evidence suggests that the liver microenvironment (LME) provides autocrine and paracrine signals originating from both parenchymal and nonparenchymal cells that collectively create both pre- and prometastatic niches for the development of hepatic metastases. These resident cells and their molecular mediators represent potential therapeutic targets for the prevention and/or treatment of liver metastases (LM). This review summarizes: (i) the current therapeutic options for treating LM, with a particular focus on colorectal cancer LM; (ii) the role of the LME in LM at each of its phases; (iii) potential targets in the LME identified through preclinical and clinical investigations; and (iv) potential therapeutic approaches for targeting elements of the LME before and/or after the onset of LM as the basis for future clinical trials. Clin Cancer Res; 23(21); 6390-9. ©2017 AACR.

Critical Review of Umbrella, Basket, and Platform Designs for Oncology Clinical Trials

The successful development of new drugs with a companion diagnostic based on genomic alteration of an oncogene has led to rethinking of all phases on clinical development of cancer drugs. We critically review some of the new clinical trial designs for biomarker-based cancer drug development. We try to clarify the objectives of the new designs and examine completed trials using these designs to evaluate what has been learned about these designs.

GOLPH3: a novel biomarker that correlates with poor survival and resistance to chemotherapy in breast cancer

The association between Golgi phosphoprotein 3 (GOLPH3) and clinical pathological characteristics, as well as the clinical outcomes of both neoadjuvant and adjuvant chemotherapies in breast cancer, remain largely unknown. In this study, we investigated the biological role and clinical significance of GOLPH3 in breast cancer. We found that GOLPH3 expression in tumor tissue was higher than that in adjacent noncancerous tissue (ANT) and fibroadenoma. GOLPH3 silencing reduced the migration, invasion, and proliferation of breast cancer cells and promoted apoptosis of the cells. Importantly, patients with high GOLPH3 expression had worse disease-free survival (DFS) and overall survival (OS), and GOLPH3 expression was correlated with clinical pathological characteristics such as molecular subtype, tumor-node-metastasis classification, and age but was not associated with surgery type. Patients with high GOLPH3 expression had poor DFS and OS in every molecular subtype, and an increase in tumor invasion and lymph node metastasis. The risk of recurrence increased with age in patients with high GOLPH3 expression, and surgery type had no influence on patient survival. This is the first study to investigate the correlation between GOLPH3 and response to chemotherapy in breast cancer. Patients with high GOLPH3 expression showed resistance to neoadjuvant and adjuvant chemotherapies, and GOLPH3 overexpression indicated a high risk of recurrence in patients who received adjuvant chemotherapy. These data suggest that GOLPH3 may be a novel biomarker that correlates with poor survival and resistance to chemotherapy in breast cancer.

Risk of severe hematologic toxicities in cancer patients treated with PARP inhibitors: a meta-analysis of randomized controlled trials

Purpose

Hematologic toxicities, including neutropenia, thrombocytopenia, and anemia, are major adverse effects of PARP inhibitors (PARPis), but the incidence rate and overall risk has not been systematically studied. Therefore, we conducted a meta-analysis of published clinical trials to investigate the incidence and relative risks (RRs) of severe (high-grade) hematologic events in cancer patients treated with PARPis.

Methods

PubMed, Embase, and oncology conference proceedings were searched for relevant studies. Eligible studies were Phase II and III randomized controlled trials (RCTs) of PARPis in cancer patients with adequate safety data on hematologic toxicities. The summary incidence, RRs, and 95% confidence intervals (CIs) were calculated.

Results

A total of 2,479 patients from 12 RCTs revealed that the incidence of PARPi-associated severe hematologic toxicities was, respectively: neutropenia: 32.9% (95% CI, 20.5%–48.3%); thrombocytopenia: 15.9% (95% CI, 9.5%–25.4%), and anemia: 9.1% (95% CI, 5.1%–15.7%). Olaparib was associated with an increased risk of severe neutropenia. Veliparib was associated with an increased risk of severe neutropenia and thrombocytopenia. Niraparib was associated with an increased risk of severe thrombocytopenia, anemia, and neutropenia. When stratified by combination therapy, significantly increased risk of hematologic toxicities was observed for patients treated with PARPis monotherapy and PARPis combined with single-agent chemotherapy.

Conclusion

Treatment with PARPis olaparib, veliparib, and niraparib is associated with a significant increase in the risk of hematologic toxicities in cancer patients, and frequent clinical monitoring should be emphasized when managing these PARPis.

Alternative Splicing in Breast Cancer and the Potential Development of Therapeutic Tools

Alternative splicing is a key molecular mechanism now considered as a hallmark of cancer that has been associated with the expression of distinct isoforms during the onset and progression of the disease. The leading cause of cancer-related deaths in women worldwide is breast cancer, and even when the role of alternative splicing in this type of cancer has been established, the function of this mechanism in breast cancer biology is not completely decoded. In order to gain a comprehensive view of the role of alternative splicing in breast cancer biology and development, we summarize here recent findings regarding alternative splicing events that have been well documented for breast cancer evolution, considering its prognostic and therapeutic value. Moreover, we analyze how the response to endocrine and chemical therapies could be affected due to alternative splicing and differential expression of variant isoforms. With all this knowledge, it becomes clear that targeting alternative splicing represents an innovative approach for breast cancer therapeutics and the information derived from current studies could guide clinical decisions with a direct impact in the clinical advances for breast cancer patients nowadays.

PARP-1 promotes tumor recurrence after warm ischemic liver graft transplantation via neutrophil recruitment and polarization

Poly (ADP-ribose) polymerase 1 (PARP-1) is a crucial contributor to exacerbate ischemia and reperfusion (IR) injury and cancer process. However, there is little research into whether PARP-1 affects the hepatocellular carcinoma (HCC) recurrence after liver transplantation. In this study, we investigated the influence of PARP-1 on hepatic neutrophil mobilizing and phenotype shifting which may lead to HCC recurrence after liver transplantation. We found that rats received the grafts with warm ischemic injury had higher risk of HCC recurrence, which was markedly prevented by pharmacological inhibition of PARP-1 after liver transplantation. In mouse models, the up-regulation of PARP-1 was closely related to the greater tumor burden and increased hepatic susceptibility to recurrence after IR injury. The reason was that high hepatic PARP-1 led to increased liver CXCL1 levels, which in turn promoted recruitment of neutrophils. Both blocking CXCL1/CXCR2 signaling pathway and depleting neutrophils decreased tumor burden. Moreover, these infiltrating neutrophils were programmed to a proangiogenic phenotype under the influence of PARP-1 in vivo after hepatic IR injury. In conclusion, IR-induced PARP-1 up-regulation increased the hepatic recruitment of neutrophils through regulation of CXCL1/CXCR2 signaling and polarized hepatic neutrophils to proangiogenic phenotype, which further promoted HCC recurrence after transplantation.

Precision Oncology: The Road Ahead

Current efforts in precision oncology largely focus on the benefit of genomics-guided therapy. Yet, advances in sequencing techniques provide an unprecedented view of the complex genetic and nongenetic heterogeneity within individual tumors. Herein, we outline the benefits of integrating genomic and transcriptomic analyses for advanced precision oncology. We summarize relevant computational approaches to detect novel drivers and genetic vulnerabilities, suitable for therapeutic exploration. Clinically relevant platforms to functionally test predicted drugs/drug combinations for individual patients are reviewed. Finally, we highlight the technological advances in single cell analysis of tumor specimens. These may ultimately lead to the development of next-generation cancer drugs, capable of tackling the hurdles imposed by genetic and phenotypic heterogeneity on current anticancer therapies.

On baseball and breast cancer

Dedicated to the memory of Dr. William Hunter Harridge and Nonie Lowry, this manuscript discusses the ups and downs associated with novel therapies in breast cancer, and applies the lessons of persistence learned from baseball to our quest for more optimal treatments, particularly in triple negative breast cancer.

Pathway-Enriched Gene Signature Associated with 53BP1 Response to PARP Inhibition in Triple-Negative Breast Cancer

Effective treatment of patients with triple-negative (ER-negative, PR-negative, HER2-negative) breast cancer remains a challenge. Although PARP inhibitors are being evaluated in clinical trials, biomarkers are needed to identify patients who will most benefit from anti-PARP therapy. We determined the responses of three PARP inhibitors (veliparib, olaparib, and talazoparib) in a panel of eight triple-negative breast cancer cell lines. Therapeutic responses and cellular phenotypes were elucidated using high-content imaging and quantitative immunofluorescence to assess markers of DNA damage (53BP1) and apoptosis (cleaved PARP). We determined the pharmacodynamic changes as percentage of cells positive for 53BP1, mean number of 53BP1 foci per cell, and percentage of cells positive for cleaved PARP. Inspired by traditional dose-response measures of cell viability, an EC₅₀ value was calculated for each cellular phenotype and each PARP inhibitor. The EC₅₀ values for both 53BP1 metrics strongly correlated with IC₅₀ values for each PARP inhibitor. Pathway enrichment analysis identified a set of DNA repair and cell cycle-associated genes that were associated with 53BP1 response following PARP inhibition. The overall accuracy of our 63 gene set in predicting response to olaparib in seven breast cancer patient-derived xenograft tumors was 86%. In triple-negative breast cancer patients who had not received anti-PARP therapy, the predicted response rate of our gene signature was 45%. These results indicate that 53BP1 is a biomarker of response to anti-PARP therapy in the laboratory, and our DNA damage response gene signature may be used to identify patients who are most likely to respond to PARP inhibition. Mol Cancer Ther; 16(12); 2892-901. ©2017 AACR.

Designing Clinical Trials That Accept New Arms: An Example in Metastatic Breast Cancer

Purpose

The majority of randomized oncology trials are two-arm studies that test the efficacy of new therapies against a standard of care, thereby assigning a large proportion of patients to nonexperimental therapies. In contrast, multiarm studies efficiently share a common control arm while evaluating multiple experimental therapies. A major bottleneck for traditional multiarm trials is the requirement that all therapies—often drugs from different companies—have to be available at the same time when the trial starts. We evaluate the potential gains of a platform design—the rolling-arms design—that adds and removes arms on a rolling basis.

Methods

We define the rolling-arms design with the goal of minimizing the complexity of random assignment and data analyses of a platform trial. We then evaluate its potential advantages in hormone receptor–positive, human epidermal growth factor receptor 2–negative advanced breast cancer. Multiple pharmaceutical companies currently test CDK4/6 inhibitors in combination with letrozole in independent two-arm trials. We conducted a simulation study to quantify the reduction in sample size, number of patients treated with the standard of care, and the average time to treatment discovery if these therapies had been tested in a rolling-arms trial.

Results

A rolling-arms platform design with two to five experimental treatments can reduce the overall sample size requirement by up to 30% compared with standard two-arm studies. It assigns up to 60% fewer patients to the control arm compared with five independent trials that test distinct treatments. Moreover, under realistic scenarios, effective experimental treatments are discovered up to 15 months earlier compared with separate two-arm trials.

Conclusion

The rolling-arms platform design is applicable to a broad variety of diseases, and under realistic scenarios, it is substantially more efficient than standard two-arm randomized trials.

PP2A regulates signaling through hormonal receptors in breast cancer with important therapeutic implications

The functional inhibition of protein phosphatase 2A (PP2A) has emerged in the last years as a common alteration in breast cancer that determines poor outcome and contributes to disease progression and aggressiveness. Furthermore, expression of estrogen receptor (ER) is a high relevant molecular event with key therapeutic implications in breast cancer, and androgen receptor (AR) signaling is involved in the pathogenesis of breast cancer and represents a novel target with crescent importance in this disease. In this review, we summarize the role of the tumor suppressor PP2A in modulating ER and AR signaling in breast cancer, the molecular mechanisms involved, and its biological and therapeutic impact.

Re-inventing drug development: A case study of the I-SPY 2 breast cancer clinical trials program

BACKGROUND

In this case study, we profile the I-SPY 2 TRIAL (Investigation of Serial studies to Predict Your Therapeutic Response with Imaging And molecular anaLysis 2), a unique breast cancer clinical trial led by researchers at 20 leading cancer centers across the US, and examine its potential to serve as a model of drug development for other disease areas. This multicenter collaboration launched in 2010 to reengineer the drug development process to be more efficient and patient-centered.

METHODS

We conduct several interviews with the I-SPY leadership as well as a literature review of relevant publications to assess the I-SPY 2 initiative.

RESULTS

To date, six drugs have graduated from I-SPY 2, identified as excellent candidates for phase 3 trials in their corresponding tumor subtype, and several others have been or are still being evaluated. These trials are also more efficient, typically involving fewer subjects and reaching conclusions more quickly, and candidates have more than twice the predicted likelihood of success in a smaller phase 3 setting compared to traditional trials.

CONCLUSIONS

We observe that I-SPY 2 possesses several novel features that could be used as a template for more efficient and cost effective drug development, namely its adaptive trial design; precompetitive network of stakeholders; and flexible infrastructure to accommodate innovation.

Challenges and Opportunities in Adapting Clinical Trial Design for Immunotherapies

Immunotherapy adds an exciting new dimension to the treatment of cancer, joining other approaches as a key pillar in the oncotherapeutics armamentarium. Immuno-oncology agents harbor unique mechanisms of antitumor activity by leveraging the host immune system, which may result in response patterns, resistance kinetics, and toxicity profiles that differ from other systemic therapies. These features have led to many discussions on ways to optimally integrate immunotherapy into cancer clinical trials. This overview provides an introduction to the four CCR Focus articles that ensue, with special thoughts paid to clinical trial endpoints, biomarker development and validation, combination strategies, and limitations that arise with increasing use of these agents. In addition, this overview examines design concepts that may be applied to invigorate clinical trials and to maximize their impact in the immuno-oncology era.

The BRCA1ness signature is associated significantly with response to PARP inhibitor treatment versus control in the I-SPY 2 randomized neoadjuvant setting

BACKGROUND

Patients with BRCA1-like tumors correlate with improved response to DNA double-strand break-inducing therapy. A gene expression-based classifier was developed to distinguish between BRCA1-like and non-BRCA1-like tumors. We hypothesized that these tumors may also be more sensitive to PARP inhibitors than standard treatments.

METHODS

A diagnostic gene expression signature (BRCA1ness) was developed using a centroid model with 128 triple-negative breast cancer samples from the EU FP7 RATHER project. This BRCA1ness signature was then tested in HER2-negative patients (n = 116) from the I-SPY 2 TRIAL who received an oral PARP inhibitor veliparib in combination with carboplatin (V-C), or standard chemotherapy alone. We assessed the association between BRCA1ness and pathologic complete response in the V-C and control arms alone using Fisher's exact test, and the relative performance between arms (biomarker × treatment interaction, likelihood ratio p < 0.05) using a logistic model and adjusting for hormone receptor status (HR).

RESULTS

We developed a gene expression signature to identify BRCA1-like status. In the I-SPY 2 neoadjuvant setting the BRCA1ness signature associated significantly with response to V-C (p = 0.03), but not in the control arm (p = 0.45). We identified a significant interaction between BRCA1ness and V-C (p = 0.023) after correcting for HR.

CONCLUSIONS

A genomic-based BRCA1-like signature was successfully translated to an expression-based signature (BRC1Aness). In the I-SPY 2 neoadjuvant setting, we determined that the BRCA1ness signature is capable of predicting benefit of V-C added to standard chemotherapy compared to standard chemotherapy alone.

TRIAL REGISTRATION

I-SPY 2 TRIAL beginning December 31, 2009: Neoadjuvant and Personalized Adaptive Novel Agents to Treat Breast Cancer (I-SPY 2), NCT01042379 .

DNA repair deficiency biomarkers and the 70-gene ultra-high risk signature as predictors of veliparib/carboplatin response in the I-SPY 2 breast cancer trial

Veliparib combined with carboplatin (VC) was an experimental regimen evaluated in the biomarker-rich neoadjuvant I-SPY 2 trial for breast cancer. VC showed improved efficacy in the triple negative signature. However, not all triple negative patients achieved pathologic complete response and some HR+HER2− patients responded. Pre-specified analysis of five DNA repair deficiency biomarkers (BRCA1/2 germline mutation; PARPi-7, BRCA1ness, and CIN70 expression signatures; and PARP1 protein) was performed on 116 HER2− patients (VC: 72 and concurrent controls: 44). We also evaluated the 70-gene ultra-high risk signature (MP1/2), one of the biomarkers used to define subtype in the trial. We used logistic modeling to assess biomarker performance. Successful biomarkers were combined using a simple voting scheme to refine the ‘predicted sensitive’ group and Bayesian modeling used to estimate the pathologic complete response rates. BRCA1/2 germline mutation status associated with VC response, but its low prevalence precluded further evaluation. PARPi-7, BRCA1ness, and MP1/2 specifically associated with response in the VC arm but not the control arm. Neither CIN70 nor PARP1 protein specifically predicted VC response. When we combined the PARPi-7 and MP1/2 classifications, the 42% of triple negative patients who were PARPi7-high and MP2 had an estimated pCR rate of 75% in the VC arm. Only 11% of HR+/HER2− patients were PARPi7-high and MP2; but these patients were also more responsive to VC with estimated pathologic complete response rates of 41%. PARPi-7, BRCA1ness and MP1/2 signatures may help refine predictions of VC response, thereby improving patient care.

Several predictive gene signatures can help identify breast cancer patients likely to respond to veliparib, an investigational PARP inhibitor, combined with the chemotherapy agent carboplatin. A team led by Denise Wolf, Christina Yau, and Laura van ‘t Veer from the University of California, San Francisco, used data from the I-SPY 2 trial to assess the predictive value of six different biomarkers in determining which women with early stage and locally advanced, aggressive breast cancer would have no signs of disease after veliparib—carboplatin treatment. They found three biomarkers with predictive value: a 7-gene expression signature that predicts breast cancer cell line sensitivity to another PARP inhibitor called olaparib; a 77-gene expression signature that detects molecular features shared with BRCA1-mutant tumours; and a 70-gene signature of recurrence risk called MammaPrint.

Systemic Therapies for Nonmetastatic Breast Cancer: The Role of Neoadjuvant and Adjuvant Chemotherapy and the Use of Endocrine Therapy

Breast cancer is a heterogenous disease, comprised of at least 3 major subtypes: hormone receptor-positive/HER2-(HR+), HER2+, and HR-/HER2-(triple negative) breast cancers. The medical management of each subype is distinct. In this article, we review contemporary data supporting the use of chemotherapy, endocrine therapy and biologic therapies, especially HER2-directed agents, in the adjuvant and neoadjuvant setting in patients with newly diagnosed nonmetastatic (stage I-III) breast cancer.

Differential Toxicity in Patients with and without DNA Repair Mutations: Phase I Study of Carboplatin and Talazoparib in Advanced Solid Tumors

Purpose: The PARP inhibitor (PARPi) talazoparib may potentiate activity of chemotherapy and toxicity in cells vulnerable to DNA damage.Experimental Design: This phase I study evaluated the safety, tolerability, pharmacokinetics, and efficacy of talazoparib and carboplatin. Pharmacokinetic modeling explored associations between DNA vulnerability and hematologic toxicity.Results: Twenty-four patients (eight males; 16 females) with solid tumors were enrolled in four cohorts at 0.75 and 1 mg daily talazoparib and weekly carboplatin (AUC 1 and 1.5, every 2 weeks or every 3 weeks), including 14 patients (58%) with prior platinum treatment. Dose-limiting toxicities included grade 3 fatigue and grade 4 thrombocytopenia; the MTD was not reached. Grade 3/4 toxicities included fatigue (13%), neutropenia (63%), thrombocytopenia (29%), and anemia (38%). After cycle 2's dose, delays/reductions were required in all patients. One complete and two partial responses occurred in germline BRCA1/2 (gBRCA1/2) patients. Four patients showed stable disease beyond 4 months, three of which had known mutations in DNA repair pathways. Pharmacokinetic toxicity modeling suggests that after three cycles of carboplatin AUC 1.5 every 3 weeks and talazoparib 1 mg daily, neutrophil counts decreased 78% [confidence interval (CI), 87-68] from baseline in gBRCA carriers and 63% (CI, 72-55) in noncarriers (P < 0.001). Pharmacokinetic toxicity modeling suggests an intermittent, pulse dosing schedule of PARP inhibition, differentiated by gBRCA mutation status, may improve the benefit/risk ratio of combination therapy.Conclusions: Carboplatin and talazoparib showed efficacy in DNA damage mutation carriers, but hematologic toxicity was more pronounced in gBRCA carriers. Carboplatin is best combined with intermittent talazoparib dosing differentiated by germline and somatic DNA damage mutation carriers. Clin Cancer Res; 23(21); 6400-10. ©2017 AACR.

Phase 1 dose-escalation study of single-agent veliparib in Japanese patients with advanced solid tumors

Veliparib (ABT‐888) is a potent, orally bioavailable poly(ADP‐ribose) polymerase‐1 and ‐2 inhibitor. This phase 1 study evaluated the tolerability, pharmacokinetic profile, safety, and preliminary antitumor activity of single‐agent veliparib in Japanese patients with advanced solid tumors. Eligible patients were assigned to treatment with veliparib at 200 or 400 mg dose; veliparib was self‐administered orally twice daily on days 1–28 of 28‐day cycles. Dose escalation, following a 3 + 3 design, defined dose‐limiting toxicities, the maximum tolerated dose, and the recommended phase 2 dose. Sixteen patients were enrolled (median age, 59 years). Fourteen patients had high‐grade serous ovarian cancer, one had primary peritoneal cancer, and one had BRCA‐mutated breast cancer. The most frequent treatment‐emergent adverse events were nausea and vomiting (93.8% each), decreased appetite (62.5%), abdominal pain, diarrhea, and malaise (31.3% each). A grade ≥3 toxicity was observed in 50% of patients; one patient each in the 200 mg (n = 4) and 400 mg (n = 12) cohorts experienced serious adverse events. Dose‐limiting toxicities were observed for one patient at the 400 mg dose. No toxicities leading to death were reported. The recommended phase 2 dose was defined as 400 mg twice daily. The veliparib pharmacokinetic profile was consistent with that reported for the Western population. Two patients, both with ovarian cancer, had a RECIST partial response. Veliparib monotherapy showed manageable tolerability and safety profiles and a predictable pharmacokinetic profile at a 400 mg twice‐daily dose, and supports the inclusion of Japanese patients in the multinational phase 3 study (NCT02470585).

De-escalating and escalating treatments for early-stage breast cancer: the St. Gallen International Expert Consensus Conference on the Primary Therapy of Early Breast Cancer 2017

The 15th St. Gallen International Breast Cancer Conference 2017 in Vienna, Austria reviewed substantial new evidence on loco-regional and systemic therapies for early breast cancer. Treatments were assessed in light of their intensity, duration and side-effects, seeking where appropriate to escalate or de-escalate therapies based on likely benefits as predicted by tumor stage and tumor biology. The Panel favored several interventions that may reduce surgical morbidity, including acceptance of 2 mm margins for DCIS, the resection of residual cancer (but not baseline extent of cancer) in women undergoing neoadjuvant therapy, acceptance of sentinel node biopsy following neoadjuvant treatment of many patients, and the preference for neoadjuvant therapy in HER2 positive and triple-negative, stage II and III breast cancer. The Panel favored escalating radiation therapy with regional nodal irradiation in high-risk patients, while encouraging omission of boost in low-risk patients. The Panel endorsed gene expression signatures that permit avoidance of chemotherapy in many patients with ER positive breast cancer. For women with higher risk tumors, the Panel escalated recommendations for adjuvant endocrine treatment to include ovarian suppression in premenopausal women, and extended therapy for postmenopausal women. However, low-risk patients can avoid these treatments. Finally, the Panel recommended bisphosphonate use in postmenopausal women to prevent breast cancer recurrence. The Panel recognized that recommendations are not intended for all patients, but rather to address the clinical needs of the majority of common presentations. Individualization of adjuvant therapy means adjusting to the tumor characteristics, patient comorbidities and preferences, and managing constraints of treatment cost and access that may affect care in both the developed and developing world.

Efficacy of the PARP Inhibitor Veliparib with Carboplatin or as a Single Agent in Patients with Germline BRCA1- or BRCA2-Associated Metastatic Breast Cancer: California Cancer Consortium Trial NCT01149083

Purpose: We aimed to establish the MTD of the poly (ADP-ribose) (PAR) polymerase inhibitor, veliparib, in combination with carboplatin in germline BRCA1- and BRCA2- (BRCA)-associated metastatic breast cancer (MBC), to assess the efficacy of single-agent veliparib, and of the combination treatment after progression, and to correlate PAR levels with clinical outcome.Experimental Design: Phase I patients received carboplatin (AUC of 5-6, every 21 days), with escalating doses (50-20 mg) of oral twice-daily (BID) veliparib. In a companion phase II trial, patients received single-agent veliparib (400 mg BID), and upon progression, received the combination at MTD. Peripheral blood mononuclear cell PAR and serum veliparib levels were assessed and correlated with outcome.Results: Twenty-seven phase I trial patients were evaluable. Dose-limiting toxicities were nausea, dehydration, and thrombocytopenia [MTD: veliparib 150 mg po BID and carboplatin (AUC of 5)]. Response rate (RR) was 56%; 3 patients remain in complete response (CR) beyond 3 years. Progression-free survival (PFS) and overall survival (OS) were 8.7 and 18.8 months. The PFS and OS were 5.2 and 14.5 months in the 44 patients in the phase II trial, with a 14% RR in BRCA1 (n = 22) and 36% in BRCA2 (n = 22). One of 30 patients responded to the combination therapy after progression on veliparib. Higher baseline PAR was associated with clinical benefit.Conclusions: Safety and efficacy are encouraging with veliparib alone and in combination with carboplatin in BRCA-associated MBC. Lasting CRs were observed when the combination was administered first in the phase I trial. Further investigation of PAR level association with clinical outcomes is warranted. Clin Cancer Res; 23(15); 4066-76. ©2017 AACR.

A diagnostic microdosing approach to investigate platinum sensitivity in non-small cell lung cancer

The platinum-based drugs cisplatin, carboplatin and oxaliplatin are often used for chemotherapy, but drug resistance is common. The prediction of resistance to these drugs via genomics is a challenging problem since hundreds of genes are involved. A possible alternative is to use mass spectrometry to determine the propensity for cells to form drug-DNA adducts-the pharmacodynamic drug-target complex for this class of drugs. The feasibility of predictive diagnostic microdosing was assessed in non-small cell lung cancer (NSCLC) cell culture and a pilot clinical trial. Accelerator mass spectrometry (AMS) was used to quantify [14 C]carboplatin-DNA monoadduct levels in the cell lines induced by microdoses and therapeutic doses of carboplatin, followed by correlation with carboplatin IC50 values for each cell line. The adduct levels in cell culture experiments were linearly proportional to dose (R2  = 0.95, p < 0.0001) and correlated with IC50 across all cell lines for microdose and therapeutically relevant carboplatin concentrations (p = 0.02 and p = 0.01, respectively). A pilot microdosing clinical trial was conducted to define protocols and gather preliminary data. Plasma pharmacokinetics (PK) and [14 C]carboplatin-DNA adducts in white blood cells and tumor tissues from six NSCLC patients were quantified via AMS. The blood plasma half-life of [14 C]carboplatin administered as a microdose was consistent with the known PK of therapeutic dosing. The optimal [14 C]carboplatin formulation for the microdose was 107 dpm/kg of body weight and 1% of the therapeutic dose for the total mass of carboplatin. No microdose-associated toxicity was observed in the patients. Additional accruals are required to significantly correlate adduct levels with response.

Repression of BET activity sensitizes homologous recombination-proficient cancers to PARP inhibition

Strategies to enhance response to poly(adenosine diphosphate-ribose) polymerase inhibitor (PARPi) in primary and acquired homologous recombination (HR)-proficient tumors would be a major advance in cancer care. We used a drug synergy screen that combined a PARPi, olaparib, with 20 well-characterized epigenetic drugs and identified bromodomain and extraterminal domain inhibitors (BETis; JQ1, I-BET762, and OTX015) as drugs that acted synergistically with olaparib in HR-proficient cancer cells. Functional assays demonstrated that repressed BET activity reduces HR and thus enhances PARPi-induced DNA damage in cancer cells. We also found that inhibition or depletion of BET proteins impairs transcription of BRCA1 and RAD51, two genes essential for HR. Moreover, BETi treatment sensitized tumors to PARP inhibition in preclinical animal models of HR-proficient breast and ovarian cancers. Finally, we showed that the BRD4 gene was focally amplified across 20 types of common cancers. Combination with BETi could greatly expand the utility of PARP inhibition to patients with HR-proficient cancer.

Does accounting for seizure frequency variability increase clinical trial power?

OBJECTIVE

Seizure frequency variability is associated with placebo responses in randomized controlled trials (RCT). Increased variability can result in drug misclassification and, hence, decreased statistical power. We investigated a new method that directly incorporated variability into RCT analysis, Z_V.

METHODS

Two models were assessed: the traditional 50%-responder rate (RR50), and the variability-corrected score, Z_V. Each predicted seizure frequency upper and lower limits using prior seizures. Accuracy was defined as percentage of time-intervals when the observed seizure frequencies were within the predicted limits. First, we tested the Z_V method on three datasets (SeizureTracker: n=3016, Human Epilepsy Project: n=107, and NeuroVista: n=15). An additional independent SeizureTracker validation dataset was used to generate a set of 200 simulated trials each for 5 different sample sizes (total N=100 to 500 by 100), assuming 20% dropout and 30% drug efficacy. "Power" was determined as the percentage of trials successfully distinguishing placebo from drug (p<0.05).

RESULTS

Prediction accuracy across datasets was, Z_V: 91-100%, RR50: 42-80%. Simulated RCT Z_V analysis achieved >90% power at N=100 per arm while RR50 required N=200 per arm.

SIGNIFICANCE

Z_V may increase the statistical power of an RCT relative to the traditional RR50.

Emerging treatments for HER2-positive early-stage breast cancer: focus on neratinib

Over the last decades, a better understanding of breast cancer heterogeneity provided tools for a biologically based personalization of anticancer treatments. In particular, the overexpression of the human epidermal growth factor receptor 2 (HER2) by tumor cells provided a specific target in these HER2-positive tumors. The development of the monoclonal antibody trastuzumab, and its approval in 1998 for the treatment of patients with metastatic disease, radically changed the natural history of this aggressive subtype of breast cancer. These findings provided strong support for the continuous research in targeting the HER2 pathway and implementing the development of new anti-HER2 targeted agents. Besides trastuzumab, a series of other anti-HER2 agents have been developed and are currently being explored for the treatment of breast cancer patients, including those diagnosed with early-stage disease. Among these agents, neratinib, an oral tyrosine kinase inhibitor that irreversibly inhibits HER1, HER2, and HER4 at the intracellular level, has shown promising results, including when administered to patients previously exposed to trastuzumab-based treatment. This article aims to review the available data on the role of the HER2 pathway in breast cancer and on the different targeted agents that have been studied or are currently under development for the treatment of patients with early-stage HER2-positive disease with a particular focus on neratinib.

Novel therapeutic strategies in the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous subtype of breast cancer that is defined by negative estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) status. Treating patients with TNBC remains clinically challenging, as patients are not candidates for endocrine or HER2-directed therapy. As a result, chemotherapy with traditional agents such as anthracyclines and taxanes remains the only available option with moderate success. Recent discoveries have revealed that TNBC is a heterogeneous disease at the clinical, histological and molecular levels. The use of biomarkers to identify distinct subsets of TNBC that derive the greatest benefit from presently approved as well as novel therapeutics has become the main focus of current research. The aim of this review is to explore the clinical and biological complexity of TNBC as well as identify novel therapeutic options that target the various molecular subsets of TNBC.

Down-regulation of PARP1 by miR-891b sensitizes human breast cancer cells to alkylating chemotherapeutic drugs

PURPOSE

Breast cancer is the most common invasive type of cancer among women. Role of different microRNAs (miRNAs) and poly(ADP-ribose) polymerases (PARPs) in breast cancer has been well established. This study aimed to explore the effects of miR-891b on sensitizing breast cancer cells to alkylating chemotherapeutic drugs through PARPs.

METHODS

The expression of miR-891b and PARP1 in human breast cancer cells HCC1806 was overexpressed by transfection with their mimics or expressing vector. Then, the transfected cells were exposed to 40 µM N-methyl-N-nitro-N-nitrosoguanidine (MNNG) for 1 h. The correlation between miR-891b and PARP1 was detected by RT-qPCR, western blot, and dual-luciferase reporter assay. Besides, MTT assay and Annexin V assay were done to measure cell proliferation and apoptosis, respectively.

RESULTS

PARP1 was a target of miR-891b, and it was negatively regulated by miR-891b. MiR-891b increased the sensitivity of the HCC1806 cells to the cytotoxic effects of MNNG through suppressing cell proliferation and increasing the percentage of apoptotic cells. Restoration of PARP1 activity in the HCC1806 cells led to loss of miR-891b mediated sensitivity of the HCC1806 cells to MNNG.

CONCLUSION

MiR-891b increases the sensitivity of the breast cancer cells (HCC1806) to the cytotoxic effects of the chemotherapeutic agent MNNG by suppressing the expression of PARP1.

Neratinib for the treatment of HER2-positive early stage breast cancer

INTRODUCTION

Despite the advances in the treatment of HER2-positive breast cancer, resistance to actual chemotherapeutic regimens eventually occurs. Neratinib, an orally available pan-inhibitor of the ERBB family, represents an interesting new option for early-stage HER2-positive breast cancer. Areas covered: In this article, the development of neratinib, with a special focus on its potential value in the treatment of early-stage HER2-positive breast cancer, has been reviewed. For this purpose, a literature search was conducted, including preclinical studies, early-phase trials in advanced cancer with neratinib in monotherapy and in combination, and phase II and large phase III trials in the early setting. Management of neratinib-induced toxicity, future perspectives for the drug, and ongoing trials are also discussed in this review. Expert commentary: Neratinib is emerging as a promising oral drug for the treatment of HER2-positive breast cancer. Although FDA and EMA approval is derived from the extended adjuvant treatment, this setting may not be the ideal scenario to obtain the beneficial effects of neratinib. Confirmatory data in the neoadjuvant setting and subgroup analysis from the ExTENET trial might bring some light into the best setting for neratinib therapy. Data from confirmatory trials in the metastatic setting are also required.

Molecular alterations in triple-negative breast cancer-the road to new treatment strategies

Triple-negative breast cancer is a heterogeneous disease and specific therapies have not been available for a long time. Therefore, conventional chemotherapy is still considered the clinical state of the art. Different subgroups of triple-negative breast cancer have been identified on the basis of protein expression, mRNA signatures, and genomic alterations. Important elements of triple-negative breast cancer biology include high proliferative activity, an increased immunological infiltrate, a basal-like and a mesenchymal phenotype, and deficiency in homologous recombination, which is in part associated with loss of BRCA1 or BRCA2 function. A minority of triple-negative tumours express luminal markers, such as androgen receptors, and have a lower proliferative activity. These biological subgroups are overlapping and currently cannot be combined into a unified model of triple-negative breast cancer biology. Nevertheless, the molecular analysis of this disease has identified potential options for targeted therapeutic intervention. This has led to promising clinical strategies, including modified chemotherapy approaches targeting the DNA damage response, angiogenesis inhibitors, immune checkpoint inhibitors, or even anti-androgens, all of which are being evaluated in phase 1-3 clinical studies. This Series paper focuses on the most relevant clinical questions, summarises the results of recent clinical trials, and gives an overview of ongoing studies and trial concepts that will lead to a more refined therapy for this tumour type.

Bayesian Adaptive Randomization and Trial Monitoring with Predictive Probability for Time-to-event Endpoint

There has been much development in Bayesian adaptive designs in clinical trials. In the Bayesian paradigm, the posterior predictive distribution characterizes the future possible outcomes given the currently observed data. Based on the interim time-to-event data, we develop a new phase II trial design by combining the strength of both Bayesian adaptive randomization and the predictive probability. By comparing the mean survival times between patients assigned to two treatment arms, more patients are assigned to the better treatment on the basis of adaptive randomization. We continuously monitor the trial using the predictive probability for early termination in the case of superiority or futility. We conduct extensive simulation studies to examine the operating characteristics of four designs: the proposed predictive probability adaptive randomization design, the predictive probability equal randomization design, the posterior probability adaptive randomization design, and the group sequential design. Adaptive randomization designs using predictive probability and posterior probability yield a longer overall median survival time than the group sequential design, but at the cost of a slightly larger sample size. The average sample size using the predictive probability method is generally smaller than that of the posterior probability design.

Precision medicine in breast cancer: reality or utopia?

Many cancers, including breast cancer, have demonstrated prognosis and support advantages thanks to the discovery of targeted therapies. The advent of these new approaches marked the rise of precision medicine, which leads to improve the diagnosis, prognosis and treatment of cancer. Precision medicine takes into account the molecular and biological specificities of the patient and their tumors that will influence the treatment determined by physicians. This new era of medicine is accessible through molecular genetics platforms, the development of high-speed sequencers and means of analysis of these data. Despite the spectacular results in the treatment of cancers including breast cancer, described in this review, not all patients however can benefit from this new strategy. This seems to be related to the many genetic mutations, which may be different from one patient to another or within the same patient. It comes to give new impetus to the research—both from a technological and biological point of view—to make the hope of precision medicine accessible to all.

The Evolution of Clinical Trials in Oncology: Defining Who Benefits from New Drugs Using Innovative Study Designs

Historically, advocates of randomized drug treatment trials in oncology contributed to the changing paradigm for testing cancer treatments in the U.S., which led to global efforts to generate evidence of promise in preclinical model systems and translate those findings into improved patient outcomes. In the age of genomic medicine, the challenge to speed the evolution of how clinical trials are conducted in patients with cancer continues.

Spotlight on landmark oncology trials: the latest evidence and novel trial designs

The era of precision oncology is marked with prominent successes in the therapy of advanced soft tissue sarcomas, breast cancer, ovarian cancer and haematological neoplasms, among others. Moreover, recent trials of immune checkpoint inhibitors in melanoma, non-small cell lung carcinoma, and head and neck cancers have significantly influenced the therapeutic landscape by providing promising evidence for immunotherapy efficacy in the adjuvant setting in high-risk locoregional disease. To speed up the introduction of targeted therapy for cancer patients, novel phase II trials are being designed, and may likely form the basis for the 'landmark trials' of the future. A special article collection in BMC Medicine, "Spotlight on landmark oncology trials", features articles from invited experts on recent clinical practice-changing trials.

The use of systemic therapies to prevent progression of inflammatory breast cancer: which targeted therapies to add on cytotoxic combinations?

INTRODUCTION

Inflammatory breast cancer is a rare but frequently fatal disease, essentially because of its high ability to develop distant metastases. Even though the prognosis of IBC was significantly improved by multimodal management, including the systematic use of cytotoxic-based induction, the prognosis remains largely dismal. Areas covered: This review presents the main achievements in the systemic treatment of IBC during the past 30 years. It focuses more specifically on recent results obtained with targeted therapies, including anti-HER2 and anti-angiogenic agents. Novel approaches under investigation are presented. Expert commentary: Current management of IBC is subtype-specific and the largest benefit has been achieved in HER2-positive disease. The identification of breakthrough therapeutic advances is eagerly awaited and will require the development of IBC-specific clinical trials. Future clinical investigations should not only aim to increase the pathological response rate but also to eradicate distant metastases, which ultimately lead to patient death.

Fertility preservation with ovarian stimulation and time to treatment in women with stage II-III breast cancer receiving neoadjuvant therapy

PURPOSE

To determine whether fertility preservation with ovarian stimulation (OS) results in treatment delay in breast cancer (BC) patients receiving neoadjuvant therapy (NAT).

METHODS

This is a retrospective study of women screened for the prospective neoadjuvant ISPY2 trial at the University of California San Francisco. All patients were <43, had stage II-III BC, and received neoadjuvant therapy. Time to initiation of NAT was compared between women who underwent OS (STIM) and women who did not (control). Patient and tumor characteristics, as well as oncologic outcomes, were compared between STIM and control groups.

RESULTS

82 patients were included (34 STIM and 48 control). STIM patients were overall younger (mean = 35 vs. 36.9 years old, p = 0.06), and more likely to be childless (79.4 vs 31.2%, p < 0.0001) than controls. Mean time from diagnosis to initiation of NAT was 40 days, with no significant difference between STIM and control groups (mean 39.8 days vs 40.9 days, p = 0.75). Mean time from diagnosis to fertility consultation was 16.3 days. With median follow-up of 79 months, 16 (19.5%) patients have recurred or died from BC. Rates of pCR, recurrence, and death were similar in both groups. Six of 34 STIM patients have undergone embryo transfer, resulting in one patient with two live births.

CONCLUSION

Fertility preservation with OS can be performed in the neoadjuvant setting without delay in initiation of systemic therapy and should be discussed with all early-stage BC patients of reproductive age.

Major clinical research advances in gynecologic cancer in 2016: 10-year special edition

In 2016, 13 topics were selected as major research advances in gynecologic oncology. For ovarian cancer, study results supporting previous ones regarding surgical preventive strategies were reported. There were several targeted agents that showed comparable responses in phase III trials, including niraparib, cediranib, and nintedanib. On the contrary to our expectations, dose-dense weekly chemotherapy regimen failed to prove superior survival outcomes compared with conventional triweekly regimen. Single-agent non-platinum treatment to prolong platinum-free-interval in patients with recurrent, partially platinum-sensitive ovarian cancer did not improve and even worsened overall survival (OS). For cervical cancer, we reviewed robust evidences of larger-scaled population-based study and cost-effectiveness of nonavalent vaccine for expanding human papillomavirus (HPV) vaccine coverage. Standard of care treatment of locally advanced cervical cancer (LACC) was briefly reviewed. For uterine corpus cancer, new findings about appropriate surgical wait time from diagnosis to surgery were reported. Advantages of minimally invasive surgery over conventional laparotomy were reconfirmed. There were 5 new gene regions that increase the risk of developing endometrial cancer. Regarding radiation therapy, Post-Operative Radiation Therapy in Endometrial Cancer (PORTEC)-3 quality of life (QOL) data were released and higher local control rate of image-guided adaptive brachytherapy was reported in LACC. In addition, 4 general oncology topics followed: chemotherapy at the end-of-life, immunotherapy with reengineering T-cells, actualization of precision medicine, and artificial intelligence (AI) to make personalized cancer therapy real. For breast cancer, adaptively randomized trials, extending aromatase inhibitor therapy, and ribociclib and palbociclib were introduced.

PARP inhibitors as precision medicine for cancer treatment

Personalized or precision medicine is an emerging treatment approach tailored to individuals or certain groups of patients based on their unique characteristics. These types of therapies guided by biomarkers tend to be more effective than traditional approaches, especially in cancer. The inhibitor against poly (ADP-ribose) polymerase (PARP), olaparib (Lynparza, AstraZeneca), which was approved by the US Food and Drug Administration (FDA) in 2014, demonstrated efficacy specifically for ovarian cancer patients harboring mutations in BRCA genes, which encode proteins in DNA double-strand break repairs. However, the response to PARP inhibitors has been less encouraging in other cancer types that also carry defects in the BRCA genes. Thus, furthering our understanding of the underlying mechanism of PARP inhibitors and resistance is critical to improve their efficacy. In this review, we summarize the results of preclinical studies and the clinical application of PARP inhibitors, and discuss the future direction of PARP inhibitors as a potential marker-guided personalized medicine for cancer treatment.