Sustained Therapeutic Response Research Articles

Drug-loaded nanoparticles for cancer therapy: a high-throughput multicellular agent-based modeling study.

Interactions between biological systems and engineered nanomaterials have become an important area of study due to the application of nanomaterials in medicine. In particular, the application of nanomaterials for cancer diagnosis or treatment presents a challenging opportunity due to the complex biology of this disease spanning multiple time and spatial scales. A system-level analysis would benefit from mathematical modeling and computational simulation to explore the interactions between anticancer drug-loaded nanoparticles (NPs), cells, and tissues, and the associated parameters driving this system and a patient's overall response. Although a number of models have explored these interactions in the past, few have focused on simulating individual cell-NP interactions. This study develops a multicellular agent-based model of cancer nanotherapy that simulates NP internalization, drug release within the cell cytoplasm, "inheritance" of NPs by daughter cells at cell division, cell pharmacodynamic response to the intracellular drug, and overall drug effect on tumor dynamics. A large-scale parallel computational framework is used to investigate the impact of pharmacokinetic design parameters (NP internalization rate, NP decay rate, anticancer drug release rate) and therapeutic strategies (NP doses and injection frequency) on the tumor dynamics. In particular, through the exploration of NP "inheritance" at cell division, the results indicate that cancer treatment may be improved when NPs are inherited at cell division for cytotoxic chemotherapy. Moreover, smaller dosage of cytostatic chemotherapy may also improve inhibition of tumor growth when cell division is not completely inhibited. This work suggests that slow delivery by "heritable" NPs can drive new dimensions of nanotherapy design for more sustained therapeutic response.

Exploring gut microbiome markers in predicting efficacy of immunotherapy against lung cancer.

8525 Background: Immunotherapy has profoundly changed the treatment landscape for lung cancer (LC) due to its tolerable safety profile and longer sustained therapeutic response. However, only about 20% of patients with locally advanced and metastatic disease can derive long-term clinical benefit from ICIs. Previous studies have suggested that the microbiome is involved in the development of LC in some way. We aimed to use the gut microbiome (GM) to model the benefit of immunotherapy and to mine the biomarkers with a global impact on immune response. Methods: We performed human gut metagenomic analysis on the responder patients and non-responder patients with immunotherapy. A total of 296 fecal samples, including baseline samples (71 responders, 98 non-responders and 72 healthy controls), and 55 samples during treatment were enrolled in our study, the taxonomic and functional features of these samples also were excavated. A machine-learning model was developed to identify responders and non-responders. At the same time, we also explored the influence of antibiotic use on the above results. Results: Specific species, Bacteroides caccae and Bacteroides uniformis, were positively correlated with responders. In non-responders, Prevotella copri was the main enrichment species. The α diversity of microbiota in responding patients was significantly higher than that in non-responding groups, and antibiotic use increased this trend. There was no significant difference in β diversity between the two groups, but LEFSE analysis also could obtain biomarkers of biological significance between the two groups. We used the biomarkers from the above analysis to construct a random forest model, and the area under the receiver operating characteristic curve (AUC) (species level: 82.10%; genus level: 79.4%). In addition, our studies suggested that metabolism such as amino acid metabolism, valine, leucine might be important in regulating the immunotherapy response that warrants further investigation. Conclusions: Overall, our study explored the relationship between microbial composition and immunotherapy efficacy in LC patients and mined relevant markers, and further research is needed to investigate the mechanisms of action of these key strains in influencing immunotherapy in the future.

Cervical dystonia: ways to achieve long-term treatment eff ects and improve patients’ quality of life

The main treatment for cervical dystonia (CD) is botulinum toxin type A (BTA) injections, but several long-term studies have found that between 19-46% of patients discontinue treatment. Anxiety and depression play a signi fi cant role in reducing the quality of life in patients with CD, according to previous surveys.Aim: to assess the dynamics of CD symptom severity, emotional disturbance, and quality of life in patients under different treatment methods.Material and methods. 61 patients with CD, 16 (26%) men and 45 (74%) women, age 50 [40; 59] years, duration of illness 4 [2; 7] years, age at onset 44 [34; 54] years, were studied. Changes in motor and aff ective disturbances, quality of life in patients with CD were assessed after 2 and 4 months in the context of diff erent treatment methods — BTA monotherapy, antidepressant (AD), combined therapy (AD + AD).Results. Combination therapy (BT + AD) was shown to be superior to BTA monotherapy in long-term follow-up of patients in terms of correction of depression, anxiety, integrative assessment of quality of life and severity of dystonia. After 4 months of treatment, the (BT + AD) subgroup maintained the positive trend achieved in dystonia severity (p < 0.001). At the end of the follow-up period in the BT group, the positive eff ect of therapy had regressed to baseline levels of dystonia severity.Conclusion. To achieve a sustained therapeutic response in patients with CD, diagnosis and appropriate correction of emotional disturbances is necessary. The potential effi cacy of antidepressants in the treatment of motor and sensory symptoms of CD requires further investigation.

Corneal gene therapy: Structural and mechanistic understanding

Cornea, a dome-shaped and transparent front part of the eye, affords 2/3rd refraction and barrier functions. Globally, corneal diseases are the leading cause of vision impairment. Loss of corneal function including opacification involve the complex crosstalk and perturbation between a variety of cytokines, chemokines and growth factors generated by corneal keratocytes, epithelial cells, lacrimal tissues, nerves, and immune cells. Conventional small-molecule drugs can treat mild-to-moderate traumatic corneal pathology but requires frequent application and often fails to treat severe pathologies. The corneal transplant surgery is a standard of care to restore vision in patients. However, declining availability and rising demand of donor corneas are major concerns to maintain ophthalmic care. Thus, the development of efficient and safe nonsurgical methods to cure corneal disorders and restore vision in vivo is highly desired. Gene-based therapy has huge potential to cure corneal blindness. To achieve a nonimmunogenic, safe and sustained therapeutic response, the selection of a relevant genes, gene editing methods and suitable delivery vectors are vital. This article describes corneal structural and functional features, mechanistic understanding of gene therapy vectors, gene editing methods, gene delivery tools, and status of gene therapy for treating corneal disorders, diseases, and genetic dystrophies.

EP08.01-100 Unlocking Primary Resistance to Checkpoint Inhibitors in Non-small Cell Lung Cancer by Metagenomic and Metabolomic

Immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 axis generate sustained therapeutic responses in a sizable minority of advanced non-small-cell lung cancer (NSCLC) patients. Several studies have shown that abnormal gut microbiome composition which may influence antitumor immune responses via metabolome led to primary resistance to ICIs, and therapeutic responses can be improved via its modulation. But functions of antitumor gut microbiome strains and metabolomic characteristics for advanced NSCLC have not been fully elucidated.

Abstract 1652: Co-targeting distinct hallmark capabilities for therapeutic benefit in pre-clinical GBM models

Abstract Glioblastoma (GBM) is the most common primary tumor arising in the central nervous system (CNS). The currently approved standard of care has transient clinical benefit as GBM tends to be exceedingly aggressive. Despite pronounced efforts to identify novel therapies, curative options for GBM do not exist and the survival rate of diagnosed patients is very low. Therefore, there is an urgent need for new treatment strategies, and one approach would be to co-target and thereby disrupt distinct hallmarks of cancer, aiming to elicit sustained therapeutic responses. We have assessed this concept by combining a tricyclic antidepressant -imipramine - with drugs targeting VEGF-A ligand or VEGF-Receptor in mice bearing de novo GBM. All monotherapies were ineffective. In notable contradistinction, we found that combinatorial regimens significantly increased survival benefit and regressed established tumors. Investigation of the basis for the therapeutic efficacy revealed that combining the VEGF pathway inhibitor with imipramine hyperactivated autophagy to the level of eliciting cancer cell-intrinsic autophagy-associated cell death, whilst modifying the tumor vasculature to be more normal-like. In addition, imipramine downregulated an M2-like phenotype of tumor-associated macrophages and reprogramed them to express chemokines attracting otherwise rare CD8 T cells, which were demonstrably contributing to the observed efficacy. As such, these hallmark co-targeting combinations served to reprogram the GBM microenvironment from immunosuppressive to pro-inflammatory, thereby sensitizing the tumors to immune checkpoint blockade, as evidenced by enhanced responses when an anti-PD-L1 therapy was included in the mix. The results to be presented will elaborate a provocative new therapeutic approach for glioblastoma that has prospect to motivate clinical evaluation in this daunting form of human cancer. Citation Format: Agnieszka Chryplewicz, Douglas Hanahan. Co-targeting distinct hallmark capabilities for therapeutic benefit in pre-clinical GBM models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1652.

Emerging immunotherapy targets in lung cancer.

Immunotherapy has become the mainstay for lung cancer treatment, providing sustained therapeutic responses and improved prognosis compared with those obtained with surgery, chemotherapy, radiotherapy, and targeted therapy. It has the potential for anti-tumor treatment and killing tumor cells by activating human immunity and has moved the targets of anti-cancer therapy from malignant tumor cells to immune cell subsets. Two kinds of immune checkpoints, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed death-1 (PD-1)/programmed death ligand 1 (PD-L1), are the main targets of current immunotherapy in lung cancer. Despite the successful outcomes achieved by immune checkpoint inhibitors, a small portion of lung cancer patients remain unresponsive to checkpoint immunotherapy or may ultimately become resistant to these agents as a result of the complex immune modulatory network in the tumor microenvironment. Therefore, it is imperative to exploit novel immunotherapy targets to further expand the proportion of patients benefiting from immunotherapy. This review summarizes the molecular features, biological function, and clinical significance of several novel checkpoints that have important roles in lung cancer immune responses beyond the CTLA-4 and PD-1/PD-L1 axes, including the markers of co-inhibitory and co-stimulatory T lymphocyte pathways and inhibitory markers of macrophages and natural killer cells.

Targeting castration-resistant prostate cancer with androgen receptor antisense oligonucleotide therapy.

Sustained therapeutic responses from traditional and next-generation antiandrogen therapies remain elusive in clinical practice due to inherent and/or acquired resistance resulting in persistent androgen receptor (AR) activity. Antisense oligonucleotides (ASO) have the ability to block target gene expression and associated protein products and provide an alternate treatment strategy for castration-resistant prostate cancer (CRPC). We demonstrate the efficacy and therapeutic potential of this approach with a Generation-2.5 ASO targeting the mouse AR in genetically engineered models of prostate cancer. Furthermore, reciprocal feedback between AR and PI3K/AKT signaling was circumvented using a combination approach of AR-ASO therapy with the potent pan-AKT inhibitor, AZD5363. This treatment strategy effectively improved treatment responses and prolonged survival in a clinically relevant mouse model of advanced CRPC. Thus, our data provide preclinical evidence to support a combination strategy of next-generation ASOs targeting AR in combination with AKT inhibition as a potentially beneficial treatment approach for CRPC.

Anti-citrullinated protein antibody titre as a predictor of abatacept treatment persistence in patients with rheumatoid arthritis: a prospective cohort study in Japan

Objective: Successful rheumatoid arthritis (RA) outcome depends on treatment efficacy in the early stages of the disease and its sustainability. It is thus critical to identify factors predicting treatment persistence with biological agents, such as abatacept. We compared clinical profiles, including early changes in autoantibody titres at 3 months, between patients with RA demonstrating sustained persistence and those discontinuing abatacept treatment.Method: We prospectively enrolled 71 and 78 active RA patients treated with abatacept and tumour necrosis factor inhibitors (TNF-Is), respectively, who had previous disease-modifying anti-rheumatic drug) failure. Clinical characteristics were compared between non-continuation and continuation groups stratified according to abatacept or TNF-I persistence for at least 12 months from treatment initiation.Results: Significantly larger decreases in rheumatoid factor titre and anti-citrullinated protein autoantibody (ACPA) titre were observed in the continuation group of abatacept therapy at 3 months, and early reduction in ACPA titre remained a significant and independent predictor of sustained persistence with abatacept in multivariate analysis. In addition, we obtained the area under the receiver operator characteristics curve of 0.904 from a model including baseline ACPA titre and reduction of ACPA titre at 3 months. Sustained reduction of RA disease activity score at 12 months was significantly and independently associated with reduced ACPA titre at 3 months.Conclusions: Persistence with abatacept and sustained therapeutic response are associated with an early reduction in ACPA titre. Prediction of abatacept continuation and efficacy will facilitate the optimal design of therapy in the early stages of RA.

Eculizumab Is Safe and Effective as a Long-term Treatment for Protein-losing Enteropathy Due to CD55 Deficiency.

Loss of the complement inhibitor CD55 leads to a syndrome of early-onset protein-losing enteropathy (PLE), associated with intestinal lymphangiectasia and susceptibility to large-vein thrombosis. The in vitro and short-term treatment benefits of eculizumab (C5-inhibitor) therapy for CD55-deficiency have been previously demonstrated. Here we present the 18-months treatment outcomes for 3 CD55-deficiency patients with sustained therapeutic response. Three CD55-deficiency patients received off-label eculizumab treatment. Clinical and laboratory treatment outcomes included frequency and consistency of bowl movements, weight, patient/parent reports of overall well-being, and serum albumin and total protein levels. Membrane attack complex deposition on leukocytes was tested by flow cytometry, before and during eculizumab treatment. Marked clinical improvement was noted in all 3 patients with resolution of PLE manifestations, that is, diarrhea, edema, malabsorption, overall well-being, growth, and quality of life. In correlation with the clinical observations, we observed progress in all laboratory outcome parameters, including increase in albumin and total protein levels, and up to 80% reduction in membrane attack complex deposition on leukocytes (P < 0.001). The progress persisted over 18 months of treatment without any severe adverse events. CD55-deficiency patients present with early-onset diarrhea, edema, severe hypoalbuminemia, abdominal pain, and malnutrition. Targeted therapy with the terminal complement inhibitor eculizumab has positive clinical and laboratory outcomes in PLE related to CD55 loss-of-function mutations, previously a life-threatening condition. Our results demonstrate the potential of genetic diagnosis to guide tailored treatment, and underscore the significant role of the complement system in the intestine.

Detection of driver mutations in BRAF can aid in diagnosis and early treatment of dedifferentiated metastatic melanoma

Dedifferentiated metastatic melanoma can pose a significant diagnostic challenge, especially if the history of primary melanoma is not known or is remote. BRAF and NRAS mutations are common melanoma driver mutations that are usually sequenced to evaluate for treatment targets. We evaluated whether BRAF and NRAS mutational testing could contribute to the diagnosis of dedifferentiated metastatic melanoma when immunostains are negative. Seven patients with melanoma who had an additional diagnosis of poorly differentiated sarcoma with negative melanocytic immunostains were tested for BRAF and NRAS mutations. Three patients showed identical BRAF mutations in the melanoma and the poorly differentiated sarcoma and hence were re-classified as metastatic dedifferentiated melanoma. In these three patients, there was an average delay of 7 months before appropriate testing, workup and treatment for metastatic melanoma was initiated. Two of these patients currently have stable metastatic disease and show sustained therapeutic response to melanoma-specific treatment including BRAF inhibitors. BRAF mutational analysis should therefore be considered in cases of poorly differentiated sarcoma, especially if there is a known history of melanoma or with unusual localization of disease. The administration of melanoma-specific treatments in such dedifferentiated cases can show therapeutic response, highlighting the importance of rendering accurate diagnoses on such cases.

Switching on the green light for chimeric antigen receptor T-cell therapy.

Adoptive cellular therapy involving genetic modification of T cells with chimeric antigen receptor (CAR) transgene offers a promising strategy to broaden the efficacy of this approach for the effective treatment of cancer. Although remarkable antitumor responses have been observed following CAR T‐cell therapy in a subset of B‐cell malignancies, this has yet to be extended in the context of solid cancers. A number of promising strategies involving reprogramming the tumor microenvironment, increasing the specificity and safety of gene‐modified T cells and harnessing the endogenous immune response have been tested in preclinical models that may have a significant impact in patients with solid cancers. This review will discuss these exciting new developments and the challenges that must be overcome to deliver a more sustained and potent therapeutic response.

Abstract 2797: Synthesis and evaluation of derivatives of selective inhibitor ERGi USU, for ERG-positive prostate cancer cells

Abstract Introduction and objectives: Prostate cancer is the most frequently diagnosed non-skin malignancy and third leading cause of cancer related deaths among men in the United States. Currently, early detected organ confined prostate cancer (CaP) is managed by active surveillance, surgery or radiation therapy. A significant subset of patients (20% to 40%) experience biochemical recurrence after definitive treatment. New AR axis inhibitors (abiraterone and enzalutamide) are leading to significant improvements in treatment of late stages of CaP. However, sustained therapeutic response remains a challenge due to high mutation load at late stages of the disease. Thus, there is an urgent need for evaluating new therapeutic targets for early stages of CaP. ERG oncoprotein and ERG dependent pathways are promising targets for early stage cancer therapy. Previously identified ERGi-USU from our laboratory, demonstrated remarkable exclusivity for inhibiting ERG protein and cell growth of ERG positive tumor cells in both in vitro and in vivo. With comprehensive structure activity relationship (SAR) studies, we generated new derivatives with substituents around the core structure to further enhance efficacy. Methods: Cell growth inhibition of small molecules was validated with established prostate cancer cell lines and normal prostate/endothelial derived cell panel. Preferential species-specific binding of ERGi-USU to human RIOK2 was confirmed by tryptophan fluorescence quenching assay. Result: Based on SAR of the parental ERGi-USU, 90 new ERGi-USU derivatives were designed using structure based predictions. Of these, 37 compounds were prioritized for chemical synthesis and biological evaluations using assays that were developed earlier in our laboratory. We completed primary screen of these compounds in cell culture models. Among these one compound (ERGi-USU-6) inhibited the growth of ERG positive prostate cancer cells with remarkable improvement IC50=70 nM. This value is in the range of current FDA approved drugs. The result also confirmed the high selectivity of ERGi-USU-6 for the inhibition of ERG positive cancer cell growth. Further, mechanistic studies revealed ERGi-USU binding and disruption of the atypical RIOK2 kinase basic function of ribosome biogenesis, due to initiation of ribosomal stress, cell cycle arrest and apoptosis in ERG positive VCaP cells. We also demonstarte preferential binding of ERGi-USU to human RIOK2 by tryptophan fluorescence quenching assay. Conclusion: The ERGi-USU-6, derivative of ERGi-USU showed improved efficacy in selectively inhibiting the growth of ERG positive cancer cells. Since ERG is a prostate cancer causing oncogene that affects approximately one third of CaP patients world-wide, early therapeutic intervention with ERGi-USU derivatives may prevent the development of late stage disease in prostate cancer patients. Citation Format: Charles Peter Xavier, Ahmed A. Mohamed, Nishat Seraj, Vineet Kumar, Taduru Sreenath, Inger L. Rosner, Gyorgy Petrovics, Meera Srivastava, Clifton L. Dalgard, Sanjay V. Malhotra, Nicole A. LaRonde, Albert Dobi, Shiv Srivastava. Synthesis and evaluation of derivatives of selective inhibitor ERGi USU, for ERG-positive prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2797.

Estimulação magnética transcraniana de repetição como estratégia de manutenção terapêutica após eletroconvulsoterapia: uma revisão conceitual

This paper reviews the theoretical bases and the empirical studies available on the use of repetitive transcranial magnetic stimulation (rTMS) as a maintenance therapy strategy after electroconvulsive therapy. Some psychiatric conditions show poor response to any type of treatment, including electroconvulsive therapy. The combined use of these two techniques has shown promising results, but more studies are needed to define the precise indications and effectiveness of this approach in terms of sustained therapeutic response.

Abstract B25: BRD4 inhibition improves the efficacy of ABT-199 in T-cell acute lymphoblastic leukemia

Abstract Introduction: Despite the improved survival of patients with T-cell acute lymphoblastic leukemia (T-ALL), therapy-resistant or refractory T-ALL remains a major clinical challenge. Recently, we and others reported promising therapeutic activity for ABT-199, a highly specific inhibitor of the anti-apoptotic protein B-cell lymphoma 2 (BCL-2), especially in immature T-ALL. Nevertheless, the occurrence of dose-limiting toxicities and the emergence of therapy resistance provides a rationale for the evaluation of ABT-199 as part of combination therapies. Indeed, previous studies have shown that ABT-199 can synergize with conventional chemotherapeutic agents in human T-ALL. BRD4 is an important bromodomain and extra-terminal (BET) protein that facilitates the recruitment of the transcriptional apparatus to acetylated chromatin. Small molecule inhibitors that target BET-bromodomain proteins, such as JQ1, can broadly affect oncogenic gene transcription and have recently emerged as powerful anti-cancer agents in a variety of hematological malignancies, including T-ALL. Here, we evaluated JQ1 and ABT-199 combination therapy and provide in vitro and in vivo evidence that combined BCL-2 and BRD4 inhibition synergistically affects leukemic tumor growth in T-ALL. Experimental Procedures: In vitro synergism between ABT-199 and JQ1 in a panel of T-ALL cell lines was determined by the combination index (CI) based on cell viability 48h after compound administration. For in vivo evaluation of the ABT-199/JQ1 combination therapy, luciferase-labeled T-ALL cells were administered by tail vein injection in immune compromised NOD scid gamma mice. Upon engraftment of leukemic cells, mice were divided into four groups and treated daily with 50mg ABT-199/kg body weight and/or 50mg JQ1/kg body weight for 13 days. The percentage of leukemic cells in the blood and bone marrow after treatment was analyzed using FACS analysis upon staining with an anti-human CD45 antibody. Results: In vitro evaluation of ABT-199 and JQ1 combination therapy revealed strong synergism (CI&amp;lt;0.5) in the T-ALL cell lines LOUCY, DND-41, ALL-SIL and TALL-1. In contrast, no or only slight synergistic effects (CI&amp;gt;0.5) were observed in other T-ALL lines, including KOPTK1, JURKAT, PEER and HPB-ALL. Notably, the degree of synergism was not defined by the IC50 values for ABT-199 or JQ1, but was significantly correlated with BCL-2 expression levels. Next, in vivo drug treatment experiments using luciferase-positive LOUCY T-ALL cells confirmed the synergistic activity of the JQ1/ABT-199 combination therapy as evaluated by bioluminescence, percentage of leukemic blasts in blood or bone marrow and spleen size. Interestingly, although ABT-199 strongly reduced the leukemic burden during the first days of treatment, the therapeutic response of single ABT-199 therapy was not durable. In contrast, JQ1/ABT-199 combination therapy resulted in a sustained therapeutic response associated with tumor regression. As expected, combination therapy resulted in enhanced levels of cleaved PARP and increased caspase activity in synergistic T-ALL cell lines, in line with induction of cellular apoptosis upon ABT-199/JQ1 treatment. To better understand the molecular mechanism by which JQ1 enhances the anti-leukemic properties of ABT-199, we defined its effect on gene expression in T-ALL cell lines. Notably, this analysis showed that the balance of pro- and anti-apoptotic BCL2 family factors was affected by JQ1 treatment. For example, JQ1 treatment caused a significant reduction in BCL2 levels, but also induced a concomitant increase in anti-apoptotic MCL1. In addition, pro-apoptotic factors, such as BIM, were also upregulated upon JQ1 treatment. Conclusions: Here, we show that BET-bromodomain inhibition can sensitize BCL2-positive human T-ALL to ABT-199 treatment by interfering with the balance of pro- and anti-apoptotic BCL2 family members. Citation Format: Sofie Peirs, Filip Matthijssens, Tim Pieters, Niels Vandamme, Geert Berx, Bruce Poppe, Pieter Van Vlierberghe. BRD4 inhibition improves the efficacy of ABT-199 in T-cell acute lymphoblastic leukemia. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Pediatric Cancer Research: From Mechanisms and Models to Treatment and Survivorship; 2015 Nov 9-12; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(5 Suppl):Abstract nr B25.

Abstract B39: BRD4 inhibition improves the efficacy of ABT-199 in T-cell acute lymphoblastic leukemia

Abstract Introduction: Despite the improved survival of patients with T-cell acute lymphoblastic leukemia (T-ALL), therapy-resistant or refractory T-ALL remains a major clinical challenge. Recently, we and others reported promising therapeutic activity for ABT-199, a highly specific inhibitor of the anti-apoptotic protein B-cell lymphoma 2 (BCL-2), especially in immature T-ALL. Nevertheless, the occurrence of dose-limiting toxicities and the emergence of therapy resistance provides a rationale for the evaluation of ABT-199 as part of combination therapies. Indeed, previous studies have shown that ABT-199 can synergize with conventional chemotherapeutic agents in human T-ALL. BRD4 is an important bromodomain and extra-terminal (BET) protein that facilitates the recruitment of the transcriptional apparatus to acetylated chromatin. Small molecule inhibitors that target BET-bromodomain proteins, such as JQ1, can broadly affect oncogenic gene transcription and have recently emerged as powerful anti-cancer agents in a variety of hematological malignancies, including T-ALL. Here, we evaluated JQ1 and ABT-199 combination therapy and provide in vitro and in vivo evidence that combined BCL-2 and BRD4 inhibition synergistically affects leukemic tumor growth in T-ALL. Experimental Procedures: In vitro synergism between ABT-199 and JQ1 in a panel of T-ALL cell lines was determined by the combination index (CI) based on cell viability 48h after compound administration. For in vivo evaluation of the ABT-199/JQ1 combination therapy, luciferase-labeled T-ALL cells were administered by tail vein injection in immune compromised NOD scid gamma mice. Upon engraftment of leukemic cells, mice were divided into four groups and treated daily with 50mg ABT-199/kg body weight and/or 50mg JQ1/kg body weight for 13 days. The percentage of leukemic cells in the blood and bone marrow after treatment was analyzed using FACS analysis upon staining with an anti-human CD45 antibody. Results: In vitro evaluation of ABT-199 and JQ1 combination therapy revealed strong synergism (CI&amp;lt;0.5) in the T-ALL cell lines LOUCY, DND-41, ALL-SIL and TALL-1. In contrast, no or only slight synergistic effects (CI&amp;gt;0.5) were observed in other T-ALL lines, including KOPTK1, JURKAT, PEER and HPB-ALL. Notably, the degree of synergism was not defined by the IC50 values for ABT-199 or JQ1, but was significantly correlated with BCL-2 expression levels. Next, in vivo drug treatment experiments using luciferase-positive LOUCY T-ALL cells confirmed the synergistic activity of the JQ1/ABT-199 combination therapy as evaluated by bioluminescence, percentage of leukemic blasts in blood or bone marrow and spleen size. Interestingly, although ABT-199 strongly reduced the leukemic burden during the first days of treatment, the therapeutic response of single ABT-199 therapy was not durable. In contrast, JQ1/ABT-199 combination therapy resulted in a sustained therapeutic response associated with tumor regression. As expected, combination therapy resulted in enhanced levels of cleaved PARP and increased caspase activity in synergistic T-ALL cell lines, in line with induction of cellular apoptosis upon ABT-199/JQ1 treatment. To better understand the molecular mechanism by which JQ1 enhances the anti-leukemic properties of ABT-199, we defined its effect on gene expression in T-ALL cell lines. Notably, this analysis showed that the balance of pro- and anti-apoptotic BCL2 family factors was affected by JQ1 treatment. For example, JQ1 treatment caused a significant reduction in BCL2 levels, but also induced a concomitant increase in anti-apoptotic MCL1. In addition, pro-apoptotic factors, such as BIM, were also upregulated upon JQ1 treatment. Conclusions: Here, we show that BET-bromodomain inhibition can sensitize BCL2-positive human T-ALL to ABT-199 treatment by interfering with the balance of pro- and anti-apoptotic BCL2 family members. Citation Format: Sofie Peirs, Filip Matthijssens, Tim Pieters, Niels Vandamme, Geert Berx, Bruce Poppe, Pieter Van Vlierberghe. BRD4 inhibition improves the efficacy of ABT-199 in T-cell acute lymphoblastic leukemia. [abstract]. In: Proceedings of the AACR Special Conference on Chromatin and Epigenetics in Cancer; Sep 24-27, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2016;76(2 Suppl):Abstract nr B39.

Sustained therapeutic response to riboflavin in a child with a progressive neurological condition, diagnosed by whole-exome sequencing.

One of the most promising outcomes of whole-exome sequencing (WES) is the alteration of medical management following an accurate diagnosis in patients with previously unresolved disorders. Although case reports of targeted therapies resulting from WES have been published, there are few reports with long-term follow-up that confirm a sustained therapeutic response. Following a diagnosis by WES of Brown–Vialetto–Van Laere Syndrome 2 (BVVLS2), high-dose riboflavin therapy was instituted in a 20-mo-old child. An immediate clinical response with stabilization of signs and symptoms was noted over the first 2–4 wk. Subsequent clinical follow-up over the following 8 mo demonstrates not just stabilization, but continuing and sustained improvements in all manifestations of this usually fatal condition, which generally includes worsening motor weakness, sensory ataxia, hearing, and vision impairments. This case emphasizes that early application of WES can transform patient care, enabling therapy that in addition to being lifesaving can sometimes reverse the disabling disease processes in a progressive condition.

Relationship between azathioprine dosage, 6-thioguanine nucleotide levels, and therapeutic response in pediatric patients with IBD treated with azathioprine.

Azathioprine (AZA) is commonly used to treat IBD either alone or in combination with mesalazine. However, there are relatively few studies concerning the relationship between AZA dose, thiopurine metabolite levels, and therapeutic response in pediatric patients treated with both AZA and mesalazine. We retrospectively investigated the relationship between AZA dose, thiopurine metabolite levels, and therapeutic response in 137 pediatric patients with IBD treated with AZA using multilevel analysis. Additional factors affecting metabolite levels and therapeutic response were also analyzed. A positive correlation was observed between AZA dosage and 6-thioguanine nucleotide (6-TGN) level (P < 0.0001). Variant TPMT genotype (P < 0.001) and concomitant use of mesalazine (P < 0.001) were predictors of higher 6-TGN levels. Leukopenia (P = 0.025) and lymphopenia (P = 0.045) were associated with higher levels of 6-TGN. Poor AZA compliance affected median 6-TGN levels (P < 0.001). The frequency of patients with median 6-TGN levels >235 pmol per 8 × 10(8) red blood cells was the highest in the sustained therapeutic response group (P = 0.015). Age, sex, IBD type, and duration of AZA therapy did not influence 6-TGN levels or therapeutic effect. AZA dosage is positively correlated with 6-TGN level. Higher 6-TGN levels are related to leukopenia, lymphopenia, and concurrent use of mesalazine. These results provide the rationale for monitoring metabolites to optimize drug dosing and minimize drug-related toxicity. In addition, maintenance of 6-TGN levels within a beneficial therapeutic range by direct monitoring should be helpful in attaining therapeutic efficacy, although this possibility should be verified in prospective studies.

A genome-wide association study on chronic HBV infection and its clinical progression in male Han-Taiwanese.

It is common to observe the clustering of chronic hepatitis B surface antigen (HBsAg) carriers in families. Intra-familial transmission of hepatitis B virus (HBV) could be the reason for the familial clustering of HBsAg carriers. Additionally, genetic and gender factors have been reported to be involved. We conducted a three-stage genome-wide association study to identify genetic factors associated with chronic HBV susceptibility. A total of 1,065 male controls and 1,623 male HBsAg carriers were included. The whole-genome genotyping was done on Illumina HumanHap550 beadchips in 304 healthy controls and HumanHap610 beadchips in 321 cases. We found that rs9277535 (HLA-DPB1, P = 4.87×10−14), rs9276370 (HLA-DQA2, P = 1.9×10−12), rs7756516 and rs7453920 (HLA-DQB2, P = 1.48×10−11 and P = 6.66×10−15 respectively) were significantly associated with persistent HBV infection. A novel SNP rs9366816 near HLA-DPA3 also showed significant association (P = 2.58×10−10). The “T-T-G-G-T” haplotype of the five SNPs further signified their association with the disease (P = 1.48×10−12; OR = 1.49). The “T-T” haplotype composed of rs7756516 and rs9276370 was more prevalent in severe disease subgroups and associated with non-sustained therapeutic response (P = 0.0262). The “G-C” haplotype was associated with sustained therapeutic response (P = 0.0132; OR = 2.49). We confirmed that HLA-DPB1, HLA-DQA2 and HLA-DQB2 loci were associated with persistent HBV infection in male Taiwan Han-Chinese. In addition, the HLA-DQA2 and -DQB2 complex was associated with clinical progression and therapeutic response.

Failed triple therapy in a treatment-experienced patient with genotype 6 hepatitis C infection

The first published report of the use of triple therapy in a patient with hepatitis C virus (HCV) genotype 6 infection-a treatment that was prescribed due to incorrect HCV genotyping and which ultimately failed-is presented. A 70-year-old male U.S. resident of Vietnamese descent requested treatment for chronic HCV infection acquired decades earlier. He reported experiencing hepatitis C treatment failures twice before-13 years prior (interferon alfa monotherapy for six months) and 7 years prior (standard dual therapy with pegylated interferon alfa-2b and ribavirin for nine months). Initial viral genotyping indicated infection with HCV genotypes 1a and 6c (a form of mixed HCV disease amenable to triple therapy), and treatment with pegylated interferon alfa-2a, ribavirin, and boceprevir was initiated. By week 8 of triple therapy, the patient's viral load had decreased from 15,700,000 (7.20 log) to 462,882 (5.67 log) IU/mL, but the viral load subsequently rebounded to baseline levels, and treatment was discontinued at week 16. When repeat HCV genotyping was performed, it was discovered that initial genotyping was incorrect and that the man's infection involved not mixed genotypes but only genotype 6; he was not an appropriate candidate for triple therapy. The case emphasizes the need for clinicians to be cognizant of potential HCV genotyping errors, particularly with regard to patients of Southeast Asian descent. Three courses of interferon-based treatment, including triple therapy with boceprevir, failed to produce a sustained therapeutic response in a 70-year-old ethnic Vietnamese man with genotype 6 HCV infection.