Treatment Of Malignant Solid Tumors Research Articles

Management of brain metastases according to molecular subtypes.

The incidence of brain metastases has markedly increased in the past 20 years owing to progress in the treatment of malignant solid tumours, earlier diagnosis by MRI and an ageing population. Although local therapies remain the mainstay of treatment for many patients with brain metastases, a growing number of systemic options are now available and/or are under active investigation. HER2-targeted therapies (lapatinib, neratinib, tucatinib and trastuzumab emtansine), alone or in combination, yield a number of intracranial responses in patients with HER2-positive breast cancer brain metastases. New inhibitors are being investigated in brain metastases from ER-positive or triple-negative breast cancer. Several generations of EGFR and ALK inhibitors have shown activity on brain metastases from EGFR and ALK mutant non-small-cell lung cancer. Immune-checkpoint inhibitors (ICIs) hold promise in patients with non-small-cell lung cancer without druggable mutations and in patients with triple-negative breast cancer. The survival of patients with brain metastases from melanoma has substantially improved after the advent of BRAF inhibitors and ICIs (ipilimumab, nivolumab and pembrolizumab). The combination of targeted agents or ICIs with stereotactic radiosurgery could further improve the response rates and survival but the risk of radiation necrosis should be monitored. Advanced neuroimaging and liquid biopsy will hopefully improve response evaluation.

Injectable corilagin/low molecular weight chitosan/PLGA-PEG-PLGA thermosensitive hydrogels for localized cancer therapy and promoting drug infiltration by modulation of tumor microenvironment.

The stroma in solid tumors severely impedes drug delivery via systemic administration to cancer cells, especially when using nano-drug delivery systems. Therefore, we developed thermosensitive and in situ-formed hydrogels based on PLGA-PEG-PLGA, which delivered corilagin and low-molecular-weight chitosan (LC) directly to tumor cells via intratumor injection and promoted drug infiltration by modulating the tumor microenvironment. The hydrogels showed the desired thermosensitive properties and enabled corilagin to elicit its highest antitumor effect. Moreover, in 4T1 tumor-bearing mice, upon combination with the hydrogels, Abraxane® exhibited a better antitumor efficacy and increased paclitaxel accumulation in the tumor tissue by degradation of the tumor matrix caused by corilagin and the uptake-promoting effect of low-molecular-weight chitosan. These results suggest that the strategy of intratumor injection of hydrogels combined with systemic administration of drugs, especially nanotherapeutics, holds promise for enhanced treatment of malignant solid tumors.

A preliminary study on molecular target identification of drugs in individualized treatment of malignant solid tumors in children

Objective: To explore the role of drug-related molecular target identification in the individualized treatment of malignant solid tumors in children. Methods: The clinical data of 40 patients diagnosed with malignant solid tumors from Beijing Tongren Hospital, Capital Medical University, between June 2017 and March 2019 were retrospectively analyzed. Immunohistochemistry, polymerase chain reaction and sequencing methods were used to determine the expression levels and mutations of tumor drug molecular targets, and to compare the efficiency as well as the incidence of toxic side effects of chemotherapy using anti-tumor drugs with various molecular targets. Results: A total of 4 tumor drug-related targets were identified in 40 tumor tissue samples, namely DNA topoisomerase-ⅡA (TOPOⅡA), β(3)-tubulin (Tubulinβ(3)), DNA topoisomerase-Ⅰ(TOPOⅠ) and dihydrofolate reductase gene polymorphisms [DHFR (C829T)]. The effective rates of platinum-based agents, methotrexate, irinotecan, vinblastine and anthracycline for malignant solid tumors in children were 90.0% (36/40), 85.0% (34/40), 70.0% (28/40), 67.5% (27/40), 62.5% (25/40), respectively. The effective rates of chemotherapy with irinotecan, methotrexate, and vinblastine in mesenchymal tumors were 68.9% (20/29), 62.1% (18/29), 68.9% (20/29), respectively, which were considerably higher than 18.2% (2/11), 36.4% (4/11) and 36.4% (4/11) in non-mesenchymal tumors, with significant differences (χ(2)=5.487, 15.345, 17.278, all P<0.05). The effective rate of chemotherapy of platinum-based drugs for non-mesenchymal tumors was 72.3% (8/11), which was significantly higher than 58.6% (17/29) in mesenchymal tumors, and the difference was statistically significant (χ(2)=11.231, P<0.05). The intensity of toxic side effects in order from high to low was anthracycline > platinum > methotrexate > vinblastine > irinotecan. Conclusion: Tumor drug-related molecular targets and the sensitivity of tumors of different origins to the same anti-tumor drug as well as side effects are predicted, which provides a theoretical and clinical basis for individualized treatment of malignant tumors in children.

Effects of cyclosporin A on the pharmacokinetics and toxicities of irinotecan mediated by UGT1A1 in vitro and in vivo.

Irinotecan (CPT-11) is a broad spectrum agent for the treatment of solid tumor malignancies, despite severe diarrhea is limiting its widespread usage. The local effects of SN-38 in the small intestine were considered to be responsible for the irinotecan-induced delayed diarrhea. It was proposed that cyclosporin A (CsA) inhibiting biliary excretion could attenuate this side effect, but in fact, it could not improve the therapeutic index of irinotecan. At present, most studies focused on the inhibition of bile excretion by cyclosporin A through the transporters MRP2 and MDR1 and its effect the irinotecan treatment in vivo. However, UDP glucuronyltransferase-1 polypeptide A1 (UGT1A1) was related to a significantly altered disposition of irinotecan and its metabolites, and was therefore associated with irinotecan-induced toxicity. This study focused on UGT1A1-mediated conversion of SN-38 to SN-38G, and systematically investigated the CsA-irinotecan interactions in vitro and in vivo. After treatment with 10 mg·kg-1 CsA for 7 days, the bile excretion of irinotecan and its metabolites decreased and AUC0-∞ increased significantly. The AUC0-∞ (SN-38G)/AUC0-∞ (SN-38) was significantly reduced when compared with that in vehicle-treated rats. In the liver microsome incubation system, the IC50 of CsA for UGT1A1 enzyme was 9.4 μM. Furthermore, the UGT1A1 mRNA and protein expression levels were significantly reduced. The present study indicated that CsA treatment could enhance the systemic exposure and toxicity of SN-38 by inhibiting the UGT1A1 enzyme. The inhibition of UGT1A1 enzyme might be a critical factor in the failure of CsA improving irinotecan's treatment index.

Abstract A69: Identification of HLA-A0201 restricted epitope of cancer/testis antigen (CTA) Hormad1 and generation of antigen-specific T-cell receptor-engineered T cells (TCR-T) for treatment of solid tumor malignancies

Abstract Purpose: Hormad1 is a novel cancer/testis antigen (CTA) that is highly expressed in several solid tumor types such as lung cancer, esophageal carcinoma, as well as head and neck cancer. High expression of Hormad1 is correlated with elevated mutational burden and reduced survival in lung adenocarcinoma, indicating that Hormad1 could be a potential target for immunotherapy. The aims of this study are to identify HLA-A0201-restricted epitope of Hormad1 and generate antigen-specific T cells and T-cell receptor (TCR)-engineered T cells (TCR-T) for adoptive cell therapy (ACT) to treat patients with Hormad1-expressing solid tumors. Methods: Candidate HLA-A0201 restricted epitopes of Hormad1 were identified by reverse-immunology and MHC class I stabilization assay. Mature HLA-A0201+ dendritic cells (mDC) were pulsed with the candidate epitope peptides and used to stimulate autologous CD25 depleted T cells. Tetramer guided sorting was used to enrich for Hormad1-specific T cells from which CTL cell lines and clones were generated. The alpha and beta TCR chains were sequenced from HORMAD1-specific, tumor-reactive CTL and cloned into a retroviral vector construct to introduce the TCR to allogeneic PBMC to generate functional TCR-T cells. Results: From 6 candidate peptides, peptide 4, which showed highest HLA-A2 binding characters, was chosen for T-cell generation. After stimulation with peptide pulsed mDC, functional CTL cell line and clones were generated from two healthy donor PBMC. Both the CTL cell line and clone selectively recognize tumor targets expressing HLA-A0201 and Hormad1. Specificity of the CTL for the HORMAD1 epitope presented by HLA-A0201 was confirmed using lines coexpressing HLA-A0201 and/or HORMAD1. Cold target inhibition assays further confirmed that the Hormad1 peptide 4 was naturally processed and presented by tumor targets. After transduction with the recombinant retroviral vector expressing the alpha and beta TCR chains of the functional CTL cell line, the resultant TCR-T cells displayed high affinity, specific tumor target killing at E:T of 1: 1.25. Moreover, these TCR-T cells specifically enhanced CD137, CD69, IFN-γ, and TNF-α expression in response to HLA-A0201-positive and Hormad1-positive tumor target cells. Conclusion: The HLA-A0201 restricted Hormad1 epitope identified in this study is a novel candidate peptide for antigen-specific vaccine development and endogenous T-cell therapy. A Hormad1-specific TCR-encoding vector was also created that conferred tumor reactivity and antigen specificity among TCR-T cells, offering a high-value product for use in adoptive T-cell therapy for patients with Hormad1-expressing solid tumor malignancies. Citation Format: Ke Pan, Yulun Chiu, Farah Hasan, Natalia Miroballi, Angelique Whitehurst, Cassian Yee. Identification of HLA-A0201 restricted epitope of cancer/testis antigen (CTA) Hormad1 and generation of antigen-specific T-cell receptor-engineered T cells (TCR-T) for treatment of solid tumor malignancies [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A69.

Optimization of drug supply for patients with malignant neoplasms in a region of the Russian Federation

The aim was to assess the possibility of optimizing the costs of drugs for cancer patients in a subject of the Russian Federation considering the expiration of patent protection period.Materials and methods. The possibility of optimizing the costs of antitumor drugs was studied using a model of a hypothetical region with a population of 2 million. A gradual replacement of the reference drugs with expiring patent protection by generics or biosimilars over 5 years was simulated. Two replacement scenarios were analyzed: 1) maintaining the drug consumption at a stable level; 2) increasing the drug consumption to the level identified in a previous retrospective analysis of the pharmaceutical market. The baseline scenario implied that the drug purchases remained unchanged (in physical and monetary terms) at the level of 2018. We calculated the difference between the drug costs in the baseline scenario and the costs of the same drugs replaced with generics or biosimilars for a 5 year period.Results. By gradually replacing the reference drugs with generics or biosimilars in a region with a population of 2 million and keeping the costs of drugs for solid tumors at the 352.2 million rubles for 5 years (baseline scenario), 69.4 million rubles can be saved. That amount represents 19.7% of the base level if the drug consumption remains at the 2018 level. With an increase in the INN consumption after the release of generics/ biosimilars, no saving is expected; on the contrary, expenses will increase by 14.1% to 400 million rubles, although, an 8.45-fold increase in consumption is projected.Conclusion. With the appearance of generics / biosimilars for the treatment of solid malignant tumors, the possibility of fund saving depends on the increase in drug consumption.

Nanofibrous Polydioxanone Depots for Prolonged Intraperitoneal Paclitaxel Delivery.

Prolonged chemodrug delivery to the tumor site is a prerequisite to maintaining its localised therapeutic concentrations for effective treatment of malignant solid tumors. The current study aims to develop implantable polymeric depots through conventional electrospinning for sustained drug delivery, specifically to the peritoneum. Non-woven electrospun mats were fabricated by simple electrospinning of Polydioxanone solution loaded with the chemodrug, Paclitaxel. The implants were subjected to the analysis of morphology, mechanical properties, degradation and drug release in phosphate buffer and patient-derived peritoneal drain fluid samples. In vivo studies were conducted by surgical knotting of these implants to the peritoneal wall of healthy mice. Non-woven electrospun mats with a thickness of 0.65±0.07 mm, weighing ~ 20 mg were fabricated by electrospinning 15 w/v% polymer loaded with 10 w/w% drug. These implants possessing good mechanical integrity showed a drug entrapment efficiency of 87.82±2.54 %. In vitro drug release studies in phosphate buffer showed a sustained profile for ~4 weeks with a burst of 10 % of total drug content, whereas this amounted to >60% in patient samples. Mice implanted with these depots remained healthy during the study period. The biphasic drug release profile obtained in vivo showed a slow trend, with peritoneal lavage and tissues retaining good drug concentrations for a sustained period. The results indicate that non-woven electrospun mats developed from biodegradable Polydioxanone polymer can serve as ideal candidates for easily implantable drug depots to address the challenges of peritoneal metastasis in ovarian cancer.

Enzyme-Activatable Interferon-Poly(α-amino acid) Conjugates for Tumor Microenvironment Potentiation.

Protein-polymer conjugation is a clinically validated approach to enhanced pharmacokinetic properties. However, the permanent attachment of polymers often leads to irreversibly reduced protein bioactivity and poor tissue penetration. As such, the use of protein-polymer conjugates for solid tumors remains elusive. Herein, we report a simple strategy using enzyme-activatable and size-shrinkable protein-polypeptide conjugates to overcome this clinical challenge. Briefly, a matrix metalloproteinase (MMP)-responsive peptide sequence is introduced between a therapeutic protein interferon (IFN) and a synthetic polypeptide P(EG3Glu)20. The resulting site-specific MMP-responsive conjugate, denoted as PEP20-M-IFN, can, therefore, release the attached P(EG3Glu)20 to achieve both protein activation and deep penetration into the tumor microenvironment (TME). Compared to a similarly produced nonresponsive analogue conjugate PEP20-IFN, our results find PEP20-M-IFN to show higher bioactivity in vitro, improved tumor retention, and deeper penetration in a MMP2-dependent manner. Moreover, systemic administration of PEP20-M-IFN shows outstanding antitumor efficacy in both OVCAR3 and SKOV3 ovarian tumor models in mice. This work highlights the releasable PEPylation strategy for protein drug potentiation at the TME and opens up new opportunities in clinics for the treatment of malignant solid tumors.

Abstract 2402: GITR cancer immunotherapy: Epitope swapping of anti-GITR TRX518 to inform functional translatability from mouse to human

Abstract Introduction: At 52.5% identity in their extracellular domains (ECDs), mouse and human GITR (CD357) sequences are only modestly conserved. Thus transitioning promising murine anti-tumor activity data with the anti-GITR DTA-1 and 2F8 Mabs to clinical trials with the non-crossreactive anti-human GITR Mab TRX518 poses a considerable limitation. Here we investigated three elements of the GITR mouse and human antibodies to address this limitation: 1) the functional epitopes targeted by anti-human GITR (TRX-518) and anti-murine GITR (DTA-1 and 2F8) antibodies; 2) their biological activities on primary T cells; and 3) the role of anti-GITR Fc receptor engagement. Results and Conclusions: Alanine scanning, amino acid substitutions and flow cytometry experiments were performed to define critical residues important for the binding of all three Mabs to their respective GITR targets. Swaps of 5-8 of these critical residues showed both the loss of murine and the gain of human directed Mab binding when residues critical for TRX18 binding were substituted into murine GITR. Likewise, the substitution of residues critical for DTA-1/2F8 binding into human GITR resulted in loss of TRX518 binding and the gain of 2F8/DTA-1 binding. We then mapped these critical residues to 3D structural models of the murine and human GITR ECDs built by contact-map guided fragment assembly simulations. Regions defined by these critical residues showed a high degree of overlap, indicating structural conservation even without amino acid identity. Thus the epitopes defined by both DTA-1 and 2F8 are homologous to those defined on human GITR by TRX518. In in vitro standard proliferation/suppression assays with effector T cells (Teff) and regulatory T cells (Tregs) isolated from human healthy donors and naïve mice respectively, TRX518, similarly to DTA-1, significantly increased proliferation, activation and pro-inflammatory cytokine production of human and murine Teff cultured alone or in the presence of Tregs. These observations indicate that Mabs directed to similar mouse and human GITR ECD epitopes result in similar biological activities. Lastly, we questioned the importance of a functional Fc domain in anti-GITR Mabs in order to translate these in vitro effects into anti-tumor activity in vivo. To this end, we compared the anti-tumor activity of DTA-1 and its aglycosyl version in the aggressive and poorly immunogenic B16 melanoma model. Both Fc and non-Fc binding DTA-1 were able to control tumor growth. This suggests that the aglycosyl-anti-GITR Mab TRX518 has the potential to be effective in the clinic despite the lack of Fc receptor engagement. These results align with our preliminary results in patients treated with TRX518 monotherapy showing reductions in Treg frequencies both in tumor biopsies and in the periphery. TRX518 would therefore appear to be well-poised for use in the treatment of solid tumor malignancies. Note: This abstract was not presented at the meeting. Citation Format: Roberta Zappasodi, Heidi Heath, Yang Zhang, Michael Haas, Min Yang, Christopher Mirabelli, Jedd D. Wolchok, Cyndi Sirard, Walter Newman, Taha Merghoub. GITR cancer immunotherapy: Epitope swapping of anti-GITR TRX518 to inform functional translatability from mouse to human [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2402.

Development and chemical characterization of biodegradable polymeric implants containing sirolimus for the treatment of malignant solid tumors.

The use of sirolimus and its analogs has been evaluated in studies aimed at combating several types of cancer; however, because of the limited bioavailability of the drug, the search for new forms of administration is required. Biodegradable polymeric implants containing sirolimus were developed and assessed as an alternative method of drug administration. Implants containing 25 % (w/w) sirolimus were prepared employing the polymer matrices chitosan, polycaprolactone and poly(lactic-co-glycolic acid) (PLGA) in two proportions: PLGA 50:50 and PLGA 75:25. Thermal analysis techniques such as thermogravimetry and differential scanning calorimetry, combined with x-ray diffraction were used to characterize and evaluate the compatibility of the constituents of the formulation. No incompatibilities were found between the components, but drug amorphization was observed in all samples. Implants made from the polymers chitosan and PCL may accelerate the degradation of SRL when these polymers are dissolved in methanol at 50 °C. HPLC analysis showed that the implant prepared with PLGA 75:25 did not present degradation products and maintained its appropriate drug content, even when dissolved in methanol and heated to 50 °C. Therefore, it represents the most suitable biodegradable polymer for use in implants developed for the treatment of malignant solid tumors. However, it is still necessary to further study the drug effects after amorphization of the crystal and also to perform stability and solubility analysis.

Criteria for Evaluation of Clinical Efficacy of Anticancer Medicines

Criteria for evaluation of clinical efficacy make it possible to assess the risk-benefit ratio of anticancer medicines that patients receive, in particular, for the treatment of solid malignant tumors. A medicine’s efficacy is assessed using special criteria called the endpoints of clinical efficacy, allowing most objective assessment of study results. It was demonstrated that nowadays clinical efficacy of anticancer drugs is assessed using «patient-centered» (overall survival and quality of life) and «tumor-centered» (response to therapy, progression-free survival, disease-free survival) endpoints. «Patient-centered» endpoints make it possible to evaluate the direct clinical benefit of chemotherapy in patients, while «tumor-centered» endpoints allow for evaluation of efficacy at earlier stages, without directly reflecting the clinical benefit. The analysis of the most suitable endpoints with the aim of making them interchangeable with the primary outcome measure – overall survival – is becoming more and more relevant in oncology. The choice of criteria of efficacy should be made taking into account the specific features of a particular oncological disease, study population and duration of therapy. The authors of the study analysed Russian and foreign literary sources containing information on criteria of efficacy of anticancer medicines and highlighted the advantages and disadvantages of these criteria. The study showed that clinical endpoints should be clinically significant, sensitive to therapy, easy to measure and interpret. It was demonstrated that comprehensive evaluation of outcome measures makes it possible to adequately assess the risk-benefit ratio of anticancer medicines.

Abstract 4554: Assessment of the efficacy and safety of checkpoint inhibitors in the treatment of solid-tumor malignancies in a community cancer hospital

Abstract Introduction: High dose chemotherapy, radiation, and/or surgical resection have historically been the standard therapy for patients with progressive malignancies. However, promising studies have shown immunotherapy may improve overall survival and reduce tumor burden in advanced disease. Checkpoint inhibitors, such as PD-1 inhibitors pembrolizumab and nivolumab and PD-L1 inhibitor atezolizumab, are approved for use in several solid tumors, but the response to these agents has been limited. This study was designed to identify predictors for the therapeutic response to immunotherapy agents in a community cancer hospital. Procedures: A retrospective review using the electronic medical record system was done to identify 43 patients treated with immunotherapy at Avera Cancer Institute. The inclusion criteria included patients who had solid organ malignancies, received checkpoint inhibitor-based immunotherapy between May 31, 2014 and May 31, 2017, and completed next generation sequencing of tumor DNA. The exclusion criteria included patients who were less than eighteen years of age, pregnant, or received care in an outreach clinic when records were not available. Data obtained from the records included age, sex, diagnosis, treatment history, immunotherapy agent used, start and end date of immunotherapy agent, clinical outcome, pathology results, adverse reactions, and next generation sequencing results of tumor DNA. The collected data was assessed for patient characteristics and biomarkers that predicted responses to immune checkpoint blockade in solid tumors. Disease progression was assessed in correspondence with the response evaluation criteria in solid tumors guidelines. Results: A total of 43 patients were included, 14 male and 29 female. The median patient age was 66 years old. The main malignancies included were, breast (11 patients), lung (10 patients), and ovarian (7 patients). On average, the patients were treated with three previous lines of therapy before receiving immunotherapy treatment. The most common immunotherapy agent was pembrolizumab, with 28 of the patients receiving this, followed by 14 patients treated with nivolumab and one treated with atezolizumab. The median time patients on immunotherapy was 118 days. Patients with longer duration of immunotherapy, fewer previous treatment lines, and higher tumor mutational burden (TMB) had the best response to checkpoint inhibitors. Conclusions: The predictive biomarkers found in this study can be used to assist in patient selection for immunotherapy in the clinical setting, including TMB and the number of lines of previous therapy. Further studies will continue to find predictors of non-response and hyperprogressors. We hope to further evaluate patients who experienced a durable response to create new hypotheses about indicators of response. Citation Format: Rachel Elsey, Nathan Smith, April Lick, Lauren Metzger, Casey Williams, Brian Leyland-Jones, Ping Ye. Assessment of the efficacy and safety of checkpoint inhibitors in the treatment of solid-tumor malignancies in a community cancer hospital [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 4554.

Identification of HLA-A0201 restricted epitope of novel cancer/testis antigens VCX/Y and generation of antigen-specific T-cell receptor engineered T cells for treatment of solid tumor malignancies.

160 Background: To identify HLA-A0201 restricted epitope of novel cancer/testis antigen VCX/Y, generate antigen specific T cells and T-cell receptor (TCR) engineered T cells for adoptive cell therapy (ACT) of solid cancer patients. Methods: Reverse-immunology method was used to identify HLA-A0201 restricted epitope of VCX/Y. The high binding score peptide or whole length of VCX3A mRNA were pulsed or transfected to mature dendritic cells (mDC) from HLA-A0201+ donor and then stimulated autologous naïve T cells. Tetramer guided sorting were performed to purify the epitope specific T cells and CTL clones were generated with limiting dilution. TCR were cloned out from high activity CTL clone and the recombinant of retrovirus vector were constructed to introduce the TCR to allogeneic PBMC to generate the TCR engineered T cells. Results: One peptide which its sequence was shared with all VCX/Y members was identified. Interesting, only CTL clone generated from simulation of VCX3A mRNA transfected DC can recognize naturally processed VCX/Y presented by HLA-A0201+ tumor cells. Cold target inhibition detection confirmed that this VCX/Y peptide was naturally processed and recognized by HLA-A0201+ CTL clone. After infection of retrovirus containing the TCR from high activity of CTL clone, the TCR engineered T cells can recognize HLA-A2+ tumor cells but not normal lung cells. Moreover, these TCR engineered T cells specifically secreted IFN-γ in response to T2 cells pulsed with peptide, as well as HLA-A0201+ and VCX/Y overexpressed tumor cells. Conclusions: VCX/Y peptide we identified is a novel candidate peptide antigen for vaccine or for endogenous adoptive T cell therapy. The correlated high activity TCR gene can generate TCR engineered T cells from patients with anti-tumor activity and offer an alternative adoptive T cell treatment for patients with VCX/Y expressing solid tumor malignancies.

The role and significance of VEGFR2+ regulatory T cells in tumor immunity.

Tumor development is closely related to angiogenesis, and VEGFR2 plays an important role in tumor angiogenesis. It is broadly expressed in the blood vessels, especially in the microvessels of tumor tissues. Furthermore, VEGFR2 is detected on the surface of the cell membrane in various immune cells, such as dendritic cells, macrophages, and regulatory T cells (Tregs). Tregs, which are one of the key negative regulatory factors in tumor immune microenvironments, show high-level expression of VEGFR2 which participates in the regulation of immunosuppressive function. VEGFR2+ Tregs play a potent suppressive role in the formation of immunosuppressive microenvironments. A large number of reports have proven the synergistic effects between targeted therapy for VEGFR2 and immunotherapy. The depression of VEGFR2 activity on T cells can significantly reduce the infiltration of Tregs into the tumor tissue. Targeted therapy for VEGFR2+ Tregs also provides a new choice for the clinical treatment of malignant solid tumors. In this paper, the role and significance of VEGFR2+ Tregs in tumor immunity in recent years are reviewed.

Asian representation in clinical trials of new drugs for the treatment of cancer.

6564 Background: In the US, statistics for Asians are often aggregated with other racial groups. This poses challenges in estimating the cancer burden and in defining cancer clinical trial enrollment targets in this demographic subgroup. ‘Asian‘ refers to persons with origins in the Far East, Southeast Asia, or the Indian sub-continent. Asians comprise 6% of the US population and the largest Asian subgroups in the US are of Chinese (22%), Filipino (19%), Asian Indian (19%), Vietnamese (10%), Korean (9%), and Japanese (7%) descent. The representation of Asian patients in global clinical trials may not be reflective of the Asian subgroups in the US. FDA conducted an analysis to describe patients categorized as ‘Asian’ in clinical trials supporting the approval of new drugs. Methods: We reviewed the marketing applications of 33 new molecular entities approved for the treatment of solid tumor malignancies between 2011- 2016 to identify trials that provided the primary evidence of safety and efficacy. Results: A total of 29,941 patients were enrolled; 17 % were Asian. Most Asian patients were enrolled in Korea (20%), Taiwan (20%), mainland China (20%), Japan (16%), and US (5%). Few patients were enrolled in India (3%); the Philippines (1%); Vietnam (0). In the US, Asian patients comprised 3% of the total number of patients enrolled. Conclusions: Asian patients represented a heterogeneous mix. A large proportion was enrolled in Taiwan (20%) and Korea (20%), whereas the largest proportion of US Asians have origins in mainland China (22%), the Philippines (19%), India (19%), and Vietnam (10%). Nevertheless, although Asians share a common ancestry, it is not clear whether data from global clinical trials are generalizable to Asian patients in the US. Therefore, strategies to improve the enrollment of US Asian patients in clinical trials are needed. Among patients enrolled in the US, 3% were Asians, a proportion that is below US Asian population estimates (6%). While most site-specific cancer incidence and death rates are lower in US Asians compared to Whites, the rates of some cancers (e. g., stomach and liver) are higher in this group. Therefore, studies are needed to determine adequate enrollment targets in this demographic subgroup.

Racial composition in trials supporting the U.S. approval of anti-cancer new molecular entities (NMEs): 2011- 2016.

6518 Background: In New Drug- and Biologics License Applications, clinical trials provide the primary safety and efficacy data upon which approval decisions are made. Low numbers of patients from racial groups that experience higher incidence and/or mortality from some cancers compared to the overall US population, may limit the generalizability of trial results. The Census estimates that the US population is 77.1%White, 13.3% Black/ African American (AA), 5.6% Asian, 1.2% American Indian/ Alaska Native (AIAN), and 0.2% Native Hawaiian/ Other Pacific Islander (NHPI). FDA conducted an analysis to compare the racial composition in trials supporting the approval of NMEs for the treatment of solid tumor malignancies. Methods: We reviewed the marketing applications of the 33 NMEs approved between 2011- 2016 to identify trials that provided the primary evidence of safety and efficacy. Results: A total of 29941 patients were enrolled. The table below illustrates enrollment by race (excluding Non-Hispanic, Hispanic, Other, Mixed Race &amp; Missing) and approval year. Conclusions: The proportion of White patients enrolled in the US (88%) is higher than the proportion of Whites in the US population. However, the enrollment of AA and NHPI/AIAN patients is low and below the proportional representation of AA and NHPI/AIAN in the US. While enrollment targets may differ across cancer type and by race, the racial composition of patients enrolled in the trials that support the approval of cancer therapeutics should be reflective of the likely US patient population for whom these agents will be prescribed. The majority of Asian patients enrolled were from RoW while the majority of AA and NHPI/AIAN patients were enrolled from the US. Increasing the representation of racial minority patients in oncology trials will require targeted recruitment and enrollment of these patients in US sites. [Table: see text]

ピラルビシン(THP)の小児固形がんにおける保険適応外使用に関するアンケート調査の結果

ピラルビシン(THP)の小児固形がんにおける保険適応外使用に関するアンケート調査の結果

Abstract 4780: RXDX-107 exhibits multiple mechanisms of intracellular delivery and results in extensive drug-induced interstrand crosslinks in solid tumor preclinical models

Abstract RXDX-107 is a dodecanol alkyl ester of bendamustine, which is then encapsulated in human serum albumin (HSA) to form nanoparticles. Bendamustine is an alkylating agent that induces interstrand DNA crosslinks (ICLs) and causes cell death via several pathways, including intrinsic apoptosis. The activity of bendamustine in the treatment of solid tumor malignancies has not been impressive, possibly due to the pharmacokinetic and limited biodistribution properties of bendamustine. RXDX-107 was designed to improve tissue biodistribution over bendamustine, which may result in superior efficacy and tolerability in patients with solid tumors. In preclinical studies, RXDX-107 displayed significant anti-tumor activity in multiple solid tumor cell lines, cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models of advanced solid tumors, such as breast, lung, and ovarian cancer. In this study, we further evaluated the mechanism of action of RXDX-107, particularly the means of entry and accumulation of drug into tumor cells. We have developed a novel analytical method to precisely quantify both dodecanol alkyl ester of bendamustine and released bendamustine in tissue culture medium and cells. Our data demonstrate that RXDX-107 is transported into cells in three active forms. Firstly, RXDX-107 slowly releases bendamustine into the extracellular medium, and released bendamustine then enters into cells. Secondly, the dodecanol alkyl ester of bendamustine is transported into cells and causes ICLs. And lastly, by measuring macropinocytosis, we also determined that human serum albumin nanoparticles mediate the intracellular entry of RXDX-107. Each of these mechanisms results in the formation of ICLs. In addition, comet assay data demonstrate that RXDX-107 displayed stronger induction of ICLs than bendamustine, and the induced ICLs persist over 48 hours in multiple solid tumor cell lines. Taken together, our data demonstrate that RXDX-107 enters and accumulates into cells via multiple mechanisms, and causes extensive and superior ICLs compared to bendamustine in several solid tumor cell lines, thereby providing a strong rationale for further investigation of this agent in solid tumor indications. Citation Format: Leenus Martin, Roopal Patel, Michael Johnson, Jerry Cao, Peter Chua, Colin Walsh, Jennifer Oliver, Pratik Multani, Robert Wild, Ralph Lin, Gary G. Li. RXDX-107 exhibits multiple mechanisms of intracellular delivery and results in extensive drug-induced interstrand crosslinks in solid tumor preclinical models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4780.

Neoadjuvant chemotherapy with XELOX regimen for locally advanced operable colon cancer patients: a prospective phase II trial (NCT02415829).

e15047Background: Several studies showed that the neoadjuvant chemotherapy (NAT) is an effective treatment of solid tumor malignancies. This study was a prospective, single-arm phase II trial to as...

Therapeutic targeting of hypoxia and hypoxia-inducible factors in cancer.

Insufficient tissue oxygenation, or hypoxia, contributes to tumor aggressiveness and has a profound impact on clinical outcomes in cancer patients. At decreased oxygen tensions, hypoxia-inducible factors (HIFs) 1 and 2 are stabilized and mediate a hypoxic response, primarily by acting as transcription factors. HIFs exert differential effects on tumor growth and affect important cancer hallmarks including cell proliferation, apoptosis, differentiation, vascularization/angiogenesis, genetic instability, tumor metabolism, tumor immune responses, and invasion and metastasis. As a consequence, HIFs mediate resistance to chemo- and radiotherapy and are associated with poor prognosis in cancer patients. Intriguingly, perivascular tumor cells can also express HIF-2α, thereby forming a "pseudohypoxic" phenotype that further contributes to tumor aggressiveness. Therefore, therapeutic targeting of HIFs in cancer has the potential to improve treatment efficacy. Different strategies to target hypoxic cancer cells and/or HIFs include hypoxia-activated prodrugs and inhibition of HIF dimerization, mRNA or protein expression, DNA binding capacity, and transcriptional activity. Here we review the functions of HIFs in the progression and treatment of malignant solid tumors. We also highlight how HIFs may be targeted to improve the management of patients with therapy-resistant and metastatic cancer.