Mechanisms of enhanced drug delivery in brain metastases with focused ultrasound-induced blood-tumor barrier disruption.

Blood-brain/blood-tumor barriers (BBB and BTB) and interstitial transport may constitute major obstacles to the transport of therapeutics in brain tumors. In this study, we examined the impact of focused ultrasound (FUS) in combination with microbubbles on the transport of two relevant chemotherapy-based anticancer agents in breast cancer brain metastases at cellular resolution: doxorubicin, a nontargeted chemotherapeutic, and ado-trastuzumab emtansine (T-DM1), an antibody-drug conjugate. Using an orthotopic xenograft model of HER2-positive breast cancer brain metastasis and quantitative microscopy, we demonstrate significant increases in the extravasation of both agents (sevenfold and twofold for doxorubicin and T-DM1, respectively), and we provide evidence of increased drug penetration (>100 vs. <20 µm and 42 ± 7 vs. 12 ± 4 µm for doxorubicin and T-DM1, respectively) after the application of FUS compared with control (non-FUS). Integration of experimental data with physiologically based pharmacokinetic (PBPK) modeling of drug transport reveals that FUS in combination with microbubbles alleviates vascular barriers and enhances interstitial convective transport via an increase in hydraulic conductivity. Experimental data demonstrate that FUS in combination with microbubbles enhances significantly the endothelial cell uptake of the small chemotherapeutic agent. Quantification with PBPK modeling reveals an increase in transmembrane transport by more than two orders of magnitude. PBPK modeling indicates a selective increase in transvascular transport of doxorubicin through small vessel wall pores with a narrow range of sizes (diameter, 10-50 nm). Our work provides a quantitative framework for the optimization of FUS-drug combinations to maximize intratumoral drug delivery and facilitate the development of strategies to treat brain metastases.

Shortwave infrared fluorescence imaging with the clinically approved near-infrared dye indocyanine green.

Fluorescence imaging is a method of real-time molecular tracking in vivo that has enabled many clinical technologies. Imaging in the shortwave IR (SWIR; 1,000-2,000 nm) promises higher contrast, sensitivity, and penetration depths compared with conventional visible and near-IR (NIR) fluorescence imaging. However, adoption of SWIR imaging in clinical settings has been limited, partially due to the absence of US Food and Drug Administration (FDA)-approved fluorophores with peak emission in the SWIR. Here, we show that commercially available NIR dyes, including the FDA-approved contrast agent indocyanine green (ICG), exhibit optical properties suitable for in vivo SWIR fluorescence imaging. Even though their emission spectra peak in the NIR, these dyes outperform commercial SWIR fluorophores and can be imaged in the SWIR, even beyond 1,500 nm. We show real-time fluorescence imaging using ICG at clinically relevant doses, including intravital microscopy, noninvasive imaging in blood and lymph vessels, and imaging of hepatobiliary clearance, and show increased contrast compared with NIR fluorescence imaging. Furthermore, we show tumor-targeted SWIR imaging with IRDye 800CW-labeled trastuzumab, an NIR dye being tested in multiple clinical trials. Our findings suggest that high-contrast SWIR fluorescence imaging can be implemented alongside existing imaging modalities by switching the detection of conventional NIR fluorescence systems from silicon-based NIR cameras to emerging indium gallium arsenide-based SWIR cameras. Using ICG in particular opens the possibility of translating SWIR fluorescence imaging to human clinical applications. Indeed, our findings suggest that emerging SWIR-fluorescent in vivo contrast agents should be benchmarked against the SWIR emission of ICG in blood.

Ang-2/VEGF bispecific antibody reprograms macrophages and resident microglia to anti-tumor phenotype and prolongs glioblastoma survival.

Inhibition of the vascular endothelial growth factor (VEGF) pathway has failed to improve overall survival of patients with glioblastoma (GBM). We previously showed that angiopoietin-2 (Ang-2) overexpression compromised the benefit from anti-VEGF therapy in a preclinical GBM model. Here we investigated whether dual Ang-2/VEGF inhibition could overcome resistance to anti-VEGF treatment. We treated mice bearing orthotopic syngeneic (Gl261) GBMs or human (MGG8) GBM xenografts with antibodies inhibiting VEGF (B20), or Ang-2/VEGF (CrossMab, A2V). We examined the effects of treatment on the tumor vasculature, immune cell populations, tumor growth, and survival in both the Gl261 and MGG8 tumor models. We found that in the Gl261 model, which displays a highly abnormal tumor vasculature, A2V decreased vessel density, delayed tumor growth, and prolonged survival compared with B20. In the MGG8 model, which displays a low degree of vessel abnormality, A2V induced no significant changes in the tumor vasculature but still prolonged survival. In both the Gl261 and MGG8 models A2V reprogrammed protumor M2 macrophages toward the antitumor M1 phenotype. Our findings indicate that A2V may prolong survival in mice with GBM by reprogramming the tumor immune microenvironment and delaying tumor growth.

Trimodal therapy for stage III-N2 non-small-cell lung carcinoma: a single center retrospective analysis.

BACKGROUND: Treatment of locally advanced non-small-cell lung cancer is based on a combined approach. To study the impact of trimodal therapy for stage III-N2 NSCLC a single centre retrospective evaluation focusing on survival and therapy-related toxicity was performed. METHODS: 71 patients diagnosed between March 2001 and August 2008 with pathologically confirmed stage III-N2 non-small-cell lung cancer at the University Clinic of Heidelberg were retrospectively analyzed. All patients were treated within trimodal therapy strategies including surgery, induction or adjuvant chemotherapy and postoperative radiotherapy. Overall survival (OS) and disease free survival (DFS) rates were calculated using the Kaplan-Meier method. The log-rank test and Fishers Exact test were applied for univariate analysis and Cox proportional regression model for multivariate analysis. RESULTS: Median survival was 32 months. 1-, 3- and 5-year overall survival (OS) rates were 84.5%, 49.6% and 35.5% respectively. Disease free survival rates at 1, 3 and 5 years were 70.4%, 41.8% and 27.4% respectively. 9 patients (12.6%) were diagnosed with a local recurrence. Multivariate analysis did not reveal any independent prognostic factors for OS, but indicated a trend for pT stage and type of surgery. In regard to toxicity 8.4% of the patients developed a clinically relevant ≥ grade 2 pneumonitis. Evaluation of the forced expiratory volume in 1 second per unit of vital capacity (FEV1/VC) before and 1-3 years post radiotherapy revealed a median decrease of 2.1%. CONCLUSIONS: Our descriptive data indicate that trimodal therapy represents an effective and safe treatment approach for patients with stage III-N2 non-small-cell lung cancer. Further prospective clinical trials are necessary in order to clearly define the impact of multimodal strategies and optimize NSCLC treatment.

A phase 2, multicenter, open-label study of anti-LAG-3 ieramilimab in combination with anti-PD-1 spartalizumab in patients with advanced solid malignancies.

Ieramilimab, a humanized anti-LAG-3 monoclonal antibody, was well tolerated in combination with the anti-PD-1 antibody spartalizumab in a phase 1 study. This phase 2 study aimed to further investigate the efficacy and safety of combination treatment in patients with selected advanced (locally advanced or metastatic) solid malignancies. Eligible patients with non-small cell lung cancer (NSCLC), melanoma, renal cell carcinoma (RCC), mesothelioma, and triple-negative breast cancer (TNBC) were grouped depending on prior anti-PD-1/L1 therapy (anti-PD-1/L1 naive or anti-PD-1/L1 pretreated). Patients received ieramilimab (400 mg) followed by spartalizumab (300 mg) every 3 weeks. The primary endpoint was objective response rate (ORR), along with safety, pharmacokinetics, and biomarker assessments. Of 235 patients, 142 were naive to anti-PD-1/L1 and 93 were pretreated with anti-PD-1/L1 antibodies. Durable responses (>24 months) were seen across all indications for patients naive to anti-PD-1/L1 and in melanoma and RCC patients pretreated with anti-PD1/L1. The most frequent study drug-related AEs were pruritus (15.5%), fatigue (10.6%), and rash (10.6%) in patients naive to anti-PD-1/L1 and fatigue (18.3%), rash (14.0%), and nausea (10.8%) in anti-PD-1/L1 pretreated patients. Biomarker assessment indicated higher expression of T-cell-inflamed gene signature at baseline among responding patients. Response to treatment was durable (>24 months) in some patients across all enrolled indications, and safety findings were in accordance with previous and current studies exploring LAG-3/PD-1 blockade.

Screening of a novel peptide targeting the proteoglycan-like region of human carbonic anhydrase IX.

The extracellular domain of human carbonic anhydrase IX (CA IX) is extended by a proteoglycan-like region (PGLR). The aim of the present study was the development of novel molecules with specificity for PGLR, which may be used for tumor targeting and imaging. PGLR was chemically synthesized, and phage display biopanning was performed. The identified ligand PGLR-P1 was labeled with 125I and characterized for target binding and metabolic stability. In vitro characterization included kinetic, competition, and internalization studies on CA IX-positive renal cell carcinoma SKRC 52 cells. The CA IX-negative cell lines HEK293 wt and BxPC3 were used as negative controls. In vitro binding experiments revealed an increasing affinity of 125I-PGLR-P1 to SKRC 52 cells but not to negative control HEK293 wt and BxPC3 cells. Internalization studies indicated an exclusive cell membrane binding. Biodistribution analysis demonstrated a higher accumulation in SKRC 52 tumors than in most normal tissues after perfusion. In vivo blocking led to a significant decrease in tumor uptake. Our findings indicate that PGLR-P1 is a promising lead structure for the development of new peptide-based ligands targeting the PGLR of CA IX and reveal challenges that need to be considered for peptide-related molecular imaging.

Neoadjuvant radiotherapy for rectal cancer: meta-analysis of randomized controlled trials.

BACKGROUND: Although neoadjuvant radiotherapy may improve local control of rectal cancer, its clinical value requires further evaluation as a result of potential side effects and advances in surgical technique. A meta-analysis was performed to assess effectiveness and safety of neoadjuvant radiotherapy in the management of rectal cancer. METHODS: The following databases were searched: the Cochrane Library, Biosis, Web of Science, Embase, ASCO Abstracts and WHO International Clinical Trials Registry Platform. Randomized controlled trials on the following comparisons were included: (1) neoadjuvant therapy versus surgery alone and (2) neoadjuvant chemoradiotherapy versus neoadjuvant radiotherapy. RESULTS: We identified 17 and 5 relevant trials that enrolled 8,568 and 2,393 patients, respectively. Neoadjuvant radiotherapy improved local control (hazard ratio 0.59; 95 % confidence interval 0.48-0.72) compared to surgery alone even after total mesorectal excision, whereas its benefit in overall survival just failed to reach statistical significance (0.93; 0.85-1.00). However, it was associated with increased perioperative mortality (1.48; 1.08-2.03), in particular if a dose of 5 Gy per fraction was administered (1.85; 1.23-2.78). Chemoradiotherapy improved local control as opposed to radiotherapy (0.53; 0.39-0.72), with no impact on perioperative outcome and long-term survival. CONCLUSIONS: Neoadjuvant radiotherapy improves local control in patients with rectal cancer, particularly when chemoradiotherapy is administered. The question if the use of more effective chemotherapy protocols improves overall survival warrants further investigation.

Biotechnology techniques for the development of new tumor specific peptides.

Peptides, proteins and antibodies are promising candidates as carriers for radionuclides in endoradiotherapy. This novel class of pharmaceuticals offers a great potential for the targeted therapy of cancer. The fact that some receptors are overexpressed in several tumor types and can be targeted by small peptides, proteins or antibodies conjugated to radionuclides has been used in the past for the development of peptide endoradiotherapeutic agents such as (90)Y-DOTATOC or radioimmunotherapy of lymphomas with Zevalin. These procedures have been shown to be powerful options for the treatment of cancer patients. Design of new peptide libraries and scaffolds combined with biopanning techniques like phage and ribosome display may lead to the discovery of new specific ligands for target structures overexpressed in malignant tumors. Display methods are high throughput systems which select for high affinity binders. These methods allow the screening of a vast amount of potential binding motifs which may be exposed to either cells overexpressing the target structures or in a cell-free system to the protein itself. Labelling these binders with radionuclides creates new potential tracers for application in diagnosis and endoradiotherapy. This review highlights the advantages and problems of phage and ribosome display for the identification and evaluation of new tumor specific peptides.

Binding of the phage display derived peptide CaIX-P1 on human colorectal carcinoma cells correlates with the expression of carbonic anhydrase IX.

Phage display represents an attractive screening strategy for the identification of novel, specific binding ligands that could be used for tumor targeting. Recently, a new peptide (CaIX-P1) with affinity for human carbonic anhydrase IX (CAIX) was identified and evaluated. The aim of the present study is to characterize the properties of CaIX-P1 for targeting human colorectal carcinoma and investigate the correlation of peptide binding with the expression of carbonic anhydrase IX. Human colorectal carcinoma HCT116 and HT29 cells were investigated for CAIX expression using Western Blot analysis. Binding and competition studies of 125I-radiolabeled CaIX-P1 were performed on HCT116 cells in vitro. FACS analysis and fluorescence microscopy studies were carried out after cell incubation with fluorescein-labeled CaIX-P1 and rhodamine-labeled anti-human CAIX-mAb. Our studies revealed an enhanced in vitro expression of carbonic anhydrase IX in HCT116 and HT29 cells with increasing cell density. Binding of 125I-labeled-CaIX-P1 on HCT116 cells increased with increasing cell density and correlated to the CAIX expression. FACS analysis demonstrated a correlation of cell labeling between FITC-CaIX-P1 and rhodamine-labeled anti-CAIX-mAb in both HCT116 and HT29 cells. The results of our study indicate that the phage display identified peptide CaIX-P1 might be an attractive candidate for the development of a ligand targeting CAIX in colorectal cancer.

Combination of phage display and molecular grafting generates highly specific tumor-targeting miniproteins.

Frankenstein's peptide: the grafting of the binding domain from miniprotein Min-23 into the sunflower trypsin inhibitor (SFTI-I) peptide scaffold preserved its in vitro and in vivo binding specificity and proteolytic stability. The combination of these peptides was shown to be tumor-specific with a good binding affinity for delta-like ligand 4 (Dll4) protein. The use of SFTI-I as a peptide scaffold is ideal for hit-to-lead development.

Preclinical Characterization and Phase I Study of an Anti-HER2-TLR7 Immune-Stimulator Antibody Conjugate in Patients with HER2+ Malignancies.

Immune-stimulator antibody conjugates (ISAC) combining tumor-targeting monoclonal antibodies with immunostimulatory agents allow targeted delivery of immune activators into tumors. NJH395 is a novel, first-in-class ISAC comprising a Toll-like receptor 7 (TLR7) agonist conjugated to an anti-HER2 antibody via a noncleavable linker payload. Preclinical characterization showed ISAC-mediated activation of myeloid cells in the presence of antigen-expressing cancer cells, with antigen targeting and TLR7 agonism contributing to antitumor activity. Safety, efficacy, immunogenicity, pharmacokinetics, and pharmacodynamics were investigated in a phase I, multicenter, open-label study in patients with HER2+ non-breast advanced malignancies (NCT03696771). Data from 18 patients enrolled in single ascending dose escalation demonstrated delivery of the TLR7-agonist payload in HER2+ tumor cells and induction of type I IFN responses, which correlated with immune modulation in the tumor microenvironment. Cytokine release syndrome was a common, but manageable, drug-related adverse event. Antidrug antibodies and neuroinflammation at high doses represented significant clinical challenges. Data provide proof-of-mechanism and critical insights for novel immunotherapies.

Phase I/II study of the LAG-3 inhibitor ieramilimab (LAG525) ± anti-PD-1 spartalizumab (PDR001) in patients with advanced malignancies.

BACKGROUND: Lymphocyte-activation gene 3 (LAG-3) is an inhibitory immunoreceptor that negatively regulates T-cell activation. This paper presents preclinical characterization of the LAG-3 inhibitor, ieramilimab (LAG525), and phase I data for the treatment of patients with advanced/metastatic solid tumors with ieramilimab ±the anti-programmed cell death-1 antibody, spartalizumab. METHODS: Eligible patients had advanced/metastatic solid tumors and progressed after, or were unsuitable for, standard-of-care therapy, including checkpoint inhibitors in some cases. Patients received ieramilimab ±spartalizumab across various dose-escalation schedules. The primary objective was to assess the maximum tolerated dose (MTD) or recommended phase II dose (RP2D). RESULTS: In total, 255 patients were allocated to single-agent ieramilimab (n=134) and combination (n=121) treatment arms. The majority (98%) had received prior antineoplastic therapy (median, 3). Four patients experienced dose-limiting toxicities in each treatment arm across various dosing cohorts. No MTD was reached. The RP2D on a 3-week schedule was declared as 400 mg ieramilimab plus 300 mg spartalizumab and, on a 4-week schedule (once every 4 weeks; Q4W), as 800 mg ieramilimab plus 400 mg spartalizumab; tumor target (LAG-3) suppression with 600 mg ieramilimab Q4W was predicted to be similar to the Q4W, RP2D schedule. Treatment-related adverse events (TRAEs) occurred in 75 (56%) and 84 (69%) patients in the single-agent and combination arms, respectively. Most common TRAEs were fatigue, gastrointestinal, and skin disorders, and were of mild severity; seven patients experienced at least one treatment-related serious adverse event in the single-agent (5%) and combination group (5.8%). Antitumor activity was observed in the combination arm, with 3 (2%) complete responses and 10 (8%) partial responses in a mixed population of tumor types. In the combination arm, eight patients (6.6%) experienced stable disease for 6 months or longer versus six patients (4.5%) in the single-agent arm. Responding patients trended towards having higher levels of immune gene expression, including CD8 and LAG3, in tumor tissue at baseline. CONCLUSIONS: Ieramilimab was well tolerated as monotherapy and in combination with spartalizumab. The toxicity profile of ieramilimab in combination with spartalizumab was comparable to that of spartalizumab alone. Modest antitumor activity was seen with combination treatment. TRIAL REGISTRATION NUMBER: NCT02460224.

Simultaneous integrated boost for adjuvant treatment of breast cancer--intensity modulated vs. conventional radiotherapy: the IMRT-MC2 trial.

BACKGROUND: Radiation therapy is an essential modality in the treatment of breast cancer. Addition of radiotherapy to surgery has significantly increased local control and survival rates of the disease. However, radiotherapy is also associated with side effects, such as tissue fibrosis or enhanced vascular morbidity. Modern radiotherapy strategies, such as intensity modulated radiotherapy (IMRT), can shorten the overall treatment time by integration of the additional tumor bed boost significantly. To what extent this might be possible without impairing treatment outcome and cosmetic results remains to be clarified. METHODS/DESIGN: The IMRT-MC2 study is a prospective, two armed, multicenter, randomized phase-III-trial comparing intensity modulated radiotherapy with integrated boost to conventional radiotherapy with consecutive boost in patients with breast cancer after breast conserving surgery. 502 patients will be recruited and randomized into two arms: patients in arm A will receive IMRT in 28 fractions delivering 50.4 Gy to the breast and 64.4 Gy to the tumor bed by integrated boost, while patients in arm B will receive conventional radiotherapy of the breast in 28 fractions to a dose of 50.4 Gy and consecutive boost in 8 fractions to a total dose of 66.4 Gy. DISCUSSION: Primary objectives of the study are the evaluation of the cosmetic results 6 weeks and 2 years post treatment and the 2- and 5-year local recurrence rates for the two different radiotherapy strategies. Secondary objectives are long term overall survival, disease free survival and quality of life. TRIAL REGISTRATION: ClinicalTrials.gov Protocol ID: NCT01322854.

Challenges in optimizing a prostate carcinoma binding peptide, identified through the phage display technology.

The transfer of peptides identified through the phage display technology to clinical applications is difficult. Major drawbacks are the metabolic degradation and label instability. The aim of our work is the optimization of DUP-1, a peptide which was identified by phage display to specifically target human prostate carcinoma. To investigate the influence of chelate conjugation, DOTA was coupled to DUP-1 and labeling was performed with ¹¹¹In. To improve serum stability cyclization of DUP-1 and targeted D-amino acid substitution were carried out. Alanine scanning was performed for identification of the binding site and based on the results peptide fragments were chemically synthesized. The properties of modified ligands were investigated in in vitro binding and competition assays. In vivo biodistribution studies were carried out in mice, carrying human prostate tumors subcutaneously. DOTA conjugation resulted in different cellular binding kinetics, rapid in vivo renal clearance and increased tumor-to-organ ratios. Cyclization and D-amino acid substitution increased the metabolic stability but led to binding affinity decrease. Fragment investigation indicated that the sequence NRAQDY might be significant for target-binding. Our results demonstrate challenges in optimizing peptides, identified through phage display libraries, and show that careful investigation of modified derivatives is necessary in order to improve their characteristics.

Therapy of thyroid carcinoma with the histone deacetylase inhibitor MS-275.

PURPOSE: Dysregulation of histone acetylation associated with an up-regulation of histone deacetylase (HDAC) activity is common in malignant tumours. Therefore, HDAC inhibitors were developed whose effects on proliferation and apoptosis have been shown in different tumour entities. Since non-iodide-concentrating thyroid carcinomas represent a therapeutic problem, this study addressed the effects of the HDAC inhibitor MS-275 on thyroid carcinoma cells. METHODS: After the antiproliferative effect of MS-275 had been proven in different human and rat thyroid carcinoma cell lines, FRO82-2, SW1736 and FTC133 cells were further investigated with respect to changes in apoptosis, cell cycle and metabolism by the annexin V/propidium iodide assay, FACS analysis and uptake experiments employing 3-O-methyl-D-(3H)glucose, fluoro-2-deoxy-D-glucose2 [5,6-(3)H] and 14C-aminoisobutyric acid (AIB). The induction of iodide transport and gene expression were investigated in 125iodide uptake experiments and real-time polymerase chain reaction (PCR). RESULTS: MS-275 induced a concentration- and time-dependent inhibition of proliferation in the thyroid carcinoma cell lines with varying IC50 values. In FRO82-2, SW1736 and FTC133 cells characterized by low, moderate and high sensitivity an up-regulation of p21CIP/WAF1 expression and G1 and/or G2 phase arrest were observed upon MS-275 exposure corresponding to the sensitivity of individual cell lines. In addition, high MS-275 concentrations increased the apoptotic cell fraction of FTC133 and SW1736 cells, whereas resistance to apoptosis and simultaneous up-regulation of Bcl-2 gene expression were observed in FRO82-2 cells. MS-275 treatment also mediated a concentration-dependent decrease of 3H-FDG uptake and an increased 3-O-methyl-D-(3H)glucose uptake in all thyroid carcinoma cell lines after 24 h, an increased uptake of both tracers in FTC133 cells after 48 h, and restored the functional activity of the sodium-iodide symporter in SW1736 and FTC133 cells up to 20- and 45-fold. CONCLUSION: MS-275 exerts dose-dependent antiproliferative effects including growth arrest, differentiation and apoptosis in some thyroid carcinoma cell lines and might, therefore, be considered for the treatment of anaplastic and non-iodide-concentrating thyroid carcinomas.

Long-term survival of cancer patients compared to heart failure and stroke: a systematic review.

BACKGROUND: Cancer, heart failure and stroke are among the most common causes of death worldwide. Investigation of the prognostic impact of each disease is important, especially for a better understanding of competing risks. Aim of this study is to provide an overview of long term survival of cancer, heart failure and stroke patients based on the results of large population- and hospital-based studies. METHODS: Records for our study were identified by searches of Medline via Pubmed. We focused on observed and relative age- and sex-adjusted 5-year survival rates for cancer in general and for the four most common malignancies in developed countries, i.e. lung, breast, prostate and colorectal cancer, as well as for heart failure and stroke. RESULTS: Twenty studies were identified and included for analysis. Five-year observed survival was about 43% for all cancer entities, 40-68% for stroke and 26-52% for heart failure. Five-year age and sex adjusted relative survival was 50-57% for all cancer entities, about 50% for stroke and about 62% for heart failure. In regard to the four most common malignancies in developed countries 5-year relative survival was 12-18% for lung cancer, 73-89% for breast cancer, 50-99% for prostate cancer and about 43-63% for colorectal cancer. Trend analysis revealed a survival improvement over the last decades. CONCLUSIONS: The results indicate that long term survival and prognosis of cancer is not necessarily worse than that of heart failure and stroke. However, a comparison of the prognostic impact of the different diseases is limited, corroborating the necessity for further systematic investigation of competing risks.

Patterns of failure after stereotactic radiotherapy of intracranial meningioma.

The aim of this work is to evaluate patterns of failure in patients with recurrent meningioma after stereotactic radiotherapy. Of 411 patients with intracranial meningioma treated with radiotherapy at our institution, 22 patients with local tumor progression diagnosed by magnetic resonance imaging (MRI) after radiotherapy (RT) were identified and further investigated. The histologic grade of the meningiomas was World Health Organization (WHO) grade I in 54.5%, WHO grade II in 27.3%, and WHO grade III in 9.1% of cases. Fourteen patients had received fractionated stereotactic RT; five patients underwent intensity-modulated RT. The median total dose was 57.6 Gy at 1.8 Gy/fraction, five times weekly. Local recurrences were divided into the dosimetric categories "central" ("in-field") and "marginal" ("out-field"). Median follow-up was 59.5 months. Eleven local failures were found to be central, and 11 were marginal. Recurrence-free survival (P < 0.05) and site of local recurrence (P < 0.05) depended statistically significantly on histology. Median recurrence-free survival was 46 months for patients with benign meningioma (WHO grade I) and 31.5 months for patients with higher-grade meningioma (WHO grade II/III). In the WHO grade I group, three recurrences were central and nine were marginal, whereas in the WHO grade II/III group seven recurrences were central and one was marginal. Median time to local tumor progression and site of local recurrence significantly depended on histological grade of meningioma. Regarding site of failure, improvement of dose coverage for benign meningiomas and dose escalation for high-grade tumors might further improve therapy outcome.

Synergy between EphA2-ILs-DTXp, a Novel EphA2-Targeted Nanoliposomal Taxane, and PD-1 Inhibitors in Preclinical Tumor Models.

Combinations of chemotherapy with immunotherapy have seen recent clinical success, including two approvals of anti-PD-1/L1 agents in combination with taxane-based chemotherapy in non-small cell lung cancer and triple-negative breast cancer. Here, we present a study on the combination activity and mechanistic rationale of a novel EphA2-targeted liposomal taxane (EphA2-ILs-DTXp) and anti-PD-1. This combination was highly active in mouse syngeneic tumor models, with complete responses observed in 3 of 5 models. In the EMT-6 tumor model, combination of EphA2-ILs-DTXp with anti-PD-1 resulted in a 60% complete response rate, with durable responses that were resistant to rechallenge. These responses were not observed in the absence of CD8+ T cells. Characterization of the immune infiltrates in EMT-6 tumors reveals increased CD8+ T cells, increased CD8+ IFNγ+ CTLs, and an increased CD8/regulatory T-cell (Treg) ratio. These immunomodulatory effects were not observed in mice treated with a combination of docetaxel and anti-PD-1. Pharmacokinetic analysis revealed that the AUC of docetaxel was increased 15 times, from 52.1 to 785 ng/mL/hour, when delivered by EphA2-ILs-DTXp. A dose reduction study of EphA2-ILs-DTXp showed a dose-response relationship for both tumor growth inhibition and the CD8/Treg ratio. Our data indicate that synergism between docetaxel and anti-PD-1 is achievable with nanoliposomal delivery.

Targeting EphA2 in Bladder Cancer Using a Novel Antibody-Directed Nanotherapeutic.

Ephrin receptor A2 (EphA2) is a member of the Ephrin/Eph receptor cell-to-cell signaling family of molecules, and it plays a key role in cell proliferation, differentiation, and migration. EphA2 is overexpressed in a broad range of cancers, and its expression is in many cases associated with poor prognosis. We recently developed a novel EphA2-targeting antibody-directed nanotherapeutic encapsulating a labile prodrug of docetaxel (EphA2-ILs-DTXp) for the treatment of EphA2-expressing malignancies. Here, we characterized the expression of EphA2 in bladder cancer using immunohistochemistry in 177 human bladder cancer samples and determined the preclinical efficacy of EphA2-ILs-DTXp in four EphA2-positive patient-derived xenograft (PDX) models of the disease, either as a monotherapy, or in combination with gemcitabine. EphA2 expression was detected in 80-100% of bladder cancer samples and correlated with shorter patient survival. EphA2 was found to be expressed in tumor cells and/or tumor-associated blood vessels in both primary and metastatic lesions with a concordance rate of approximately 90%. The EphA2-targeted antibody-directed nanotherapeutic EphA2-ILs-DTXp controlled tumor growth, mediated greater regression, and was more active than free docetaxel at equitoxic dosing in all four EphA2-positive bladder cancer PDX models. Combination of EphA2-ILs-DTXp and gemcitabine in one PDX model led to improved tumor growth control compared to monotherapies or the combination of free docetaxel and gemcitabine. These data demonstrating the prevalence of EphA2 in bladder cancers and efficacy of EphA2-ILs-DTXp in PDX models support the clinical exploration of EphA2 targeting in bladder cancer.