A Phase 2 Study of Sitravatinib in Combination with Nivolumab in Patients with Advanced or Metastatic Urothelial Carcinoma.

BACKGROUND AND OBJECTIVE: Checkpoint inhibitor therapy (CPI) has demonstrated survival benefits in urothelial carcinoma (UC); however, not all patients benefit from CPI due to resistance. Combining sitravatinib, a multitargeted receptor tyrosine kinase inhibitor of TYRO3, AXL, and MERTK (TAM) receptors and VEGFR2, with CPI may improve antitumor responses. Our objective was to assess the efficacy and safety of sitravatinib plus nivolumab in patients with advanced/metastatic UC. METHODS: The 516-003 trial (NCT03606174) is an open-label, multicohort phase 2 study evaluating sitravatinib plus nivolumab in patients with advanced/metastatic UC enrolled in eight cohorts depending on prior treatment with CPI, platinum-based chemotherapy (PBC), or antibody-drug conjugate (ADC). Overall, 244 patients were enrolled and treated with sitravatinib plus nivolumab (median follow-up 14.1-38.2 mo). Sitravatinib (free-base capsules 120 mg once daily [QD] or malate capsule 100 mg QD) plus nivolumab (240 mg every 2 wk/480 mg every 4 wk intravenously). KEY FINDINGS AND LIMITATIONS: The primary endpoint was objective response rate (ORR; RECIST v1.1). The secondary endpoints included progression-free survival (PFS) and safety. The Predictive probability design and confidence interval methods were used. Among patients previously treated with PBC, ORR, and median PFS were 32.1% and 3.9 mo in CPI-naïve patients (n = 53), 14.9% and 3.9 mo in CPI-refractory patients (n = 67), and 5.4% and 3.7 mo in CPI- and ADC-refractory patients (n = 56), respectively. Across all cohorts, grade 3 treatment-related adverse events (TRAEs) occurred in 51.2% patients and grade 4 in 3.3%, with one treatment-related death (cardiac failure). Immune-related adverse events occurred in 50.4% patients. TRAEs led to sitravatinib/nivolumab discontinuation in 6.1% patients. CONCLUSIONS AND CLINICAL IMPLICATIONS: Sitravatinib plus nivolumab demonstrated a manageable safety profile but did not result in clinically meaningful ORRs in patients with advanced/metastatic UC in the eight cohorts studied. PATIENT SUMMARY: In this study, the combination of two anticancer drugs, sitravatinib and nivolumab, resulted in manageable side effects but no meaningful responses in patients with bladder cancer.

Phase II trial of neoadjuvant sitravatinib plus nivolumab in patients undergoing nephrectomy for locally advanced clear cell renal cell carcinoma.

Sitravatinib is an immunomodulatory tyrosine kinase inhibitor that can augment responses when combined with programmed death-1 inhibitors such as nivolumab. We report a single-arm, interventional, phase 2 study of neoadjuvant sitravatinib in combination with nivolumab in patients with locally advanced clear cell renal cell carcinoma (ccRCC) prior to curative nephrectomy (NCT03680521). The primary endpoint was objective response rate (ORR) prior to surgery with a null hypothesis ORR = 5% and the alternative hypothesis set at ORR = 30%. Secondary endpoints were safety; pharmacokinetics (PK) of sitravatinib; immune effects, including changes in programmed cell death-ligand 1 expression; time-to-surgery; and disease-free survival (DFS). Twenty patients were evaluable for safety and 17 for efficacy. The ORR was 11.8%, and 24-month DFS probability was 88·0% (95% CI 61.0 to 97.0). There were no grade 4/5 treatment-related adverse events. Sitravatinib PK did not change following the addition of nivolumab. Correlative blood and tissue analyses showed changes in the tumour microenvironment resulting in an immunologically active tumour by the time of surgery (median time-to-surgery: 50 days). The primary endpoint of this study was not met as short-term neoadjuvant sitravatinib and nivolumab did not substantially increase ORR.

A Preliminary Study of Deep-Learning Algorithm for Analyzing Multiplex Immunofluorescence Biomarkers in Body Fluid Cytology Specimens.

INTRODUCTION: Multiplex biomarker analysis of cytological body fluid specimens is often used to assist cytologists in distiguishing metastatic cancer cells from reactive mesothelial cells. However, evaluating biomarker expression visually may be challenging, especially when the cells of interest are scant. Deep-learning algorithms (DLAs) may be able to assist cytologists in analyzing multiple biomarker expression at the single cell level in the multiplex fluorescence imaging (MFI) setting. This preliminary study was performed to test the feasibility of using DLAs to identify immunofluorescence-stained metastatic adenocarcinoma cells in body fluid cytology samples. METHODS: A DLA was developed to analyze MFI-stained cells in body fluid cytological samples. A total of 41 pleural fluid samples, comprising of 20 positives and 21 negatives, were retrospectively collected. Multiplex immunofluorescence labeling for MOC31, BerEP4, and calretinin, were performed on cell block sections, and results were analyzed by manual analysis (manual MFI) and DLA analysis (MFI-DLA) independently. RESULTS: All cases with positive original cytological diagnoses showed positive results either by manual MFI or MFI-DLA, but 2 of the 14 (14.3%) original cytologically negative cases had rare cells with positive MOC31 and/or BerEP4 staining in addition to calretinin. Manual MFI analysis and MFI-DLA showed 100% concordance. CONCLUSION: MFI combined with DLA provides a potential tool to assist in cytological diagnosis of metastatic malignancy in body fluid samples. Larger studies are warranted to test the clinical validity of the approach.

Biomarkers that may predict response to immunotherapy in ovarian malignancies.

PURPOSE OF REVIEW: Immune checkpoint blockade (ICB) is a promising area of cancer therapeutic research. Therapies targeting the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) mechanism of tumor immune evasion have resulted in durable responses in many difficult-to-treat tumor types. While these inhibitors are being actively investigated in clinical trials for ovarian cancer, most patients fail to respond to initial treatment with immune therapy. This review focuses on biomarkers for predicting response to treatment, and discusses clinical trials using ICB for recurrent ovarian cancer. RECENT FINDINGS: While PD-L1 detection by immunohistochemistry (IHC) is approved as a companion or complementary diagnostic in some cancers, there are many limitations with its use as a predictive marker. Recent research has explored biomarkers beyond PD-L1 that assess for somatic mutations, immune cell infiltrate, and gene signatures. SUMMARY: With improved understanding of the tumor microenvironment and genomic classifications of ovarian tumors, new diagnostics and biomarkers that supplement conventional IHC may help predict response to therapy.

A smartphone dongle for diagnosis of infectious diseases at the point of care.

This work demonstrates that a full laboratory-quality immunoassay can be run on a smartphone accessory. This low-cost dongle replicates all mechanical, optical, and electronic functions of a laboratory-based enzyme-linked immunosorbent assay (ELISA) without requiring any stored energy; all necessary power is drawn from a smartphone. Rwandan health care workers used the dongle to test whole blood obtained via fingerprick from 96 patients enrolling into care at prevention of mother-to-child transmission clinics or voluntary counseling and testing centers. The dongle performed a triplexed immunoassay not currently available in a single test format: HIV antibody, treponemal-specific antibody for syphilis, and nontreponemal antibody for active syphilis infection. In a blinded experiment, health care workers obtained diagnostic results in 15 min from our triplex test that rivaled the gold standard of laboratory-based HIV ELISA and rapid plasma reagin (a screening test for syphilis), with sensitivity of 92 to 100% and specificity of 79 to 100%, consistent with needs of current clinical algorithms. Patient preference for the dongle was 97% compared to laboratory-based tests, with most pointing to the convenience of obtaining quick results with a single fingerprick. This work suggests that coupling microfluidics with recent advances in consumer electronics can make certain laboratory-based diagnostics accessible to almost any population with access to smartphones.

Assembly of complex cell microenvironments using geometrically docked hydrogel shapes.

Cellular communities in living tissues act in concert to establish intricate microenvironments, with complexity difficult to recapitulate in vitro. We report a method for docking numerous cellularized hydrogel shapes (100-1,000 µm in size) into hydrogel templates to construct 3D cellular microenvironments. Each shape can be uniquely designed to contain customizable concentrations of cells and molecular species, and can be placed into any spatial configuration, providing extensive compositional and geometric tunability of shape-coded patterns using a highly biocompatible hydrogel material. Using precisely arranged hydrogel shapes, we investigated migratory patterns of human mesenchymal stem cells and endothelial cells. We then developed a finite element gradient model predicting chemotactic directions of cell migration in micropatterned cocultures that were validated by tracking ∼2,500 individual cell trajectories. This simple yet robust hydrogel platform provides a comprehensive approach to the assembly of 3D cell environments.

Mobile device for disease diagnosis and data tracking in resource-limited settings.

BACKGROUND: Collection of epidemiological data and care of patients are hampered by lack of access to laboratory diagnostic equipment and patients' health records in resource-limited settings. We engineered a low-cost mobile device that combines cell-phone and satellite communication technologies with fluid miniaturization techniques for performing all essential ELISA functions. METHODS: We assessed the device's ability to perform HIV serodiagnostic testing in Rwanda and synchronize results in real time with electronic health records. We tested serum, plasma, and whole blood samples collected in Rwanda and on a commercially available sample panel made of mixed antibody titers. RESULTS: HIV testing on 167 Rwandan patients evaluated for HIV, viral hepatitis, and sexually transmitted infections yielded diagnostic sensitivity and specificity of 100% and 99%, respectively. Testing on 40 Rwandan whole-blood samples-using 1 µL of sample per patient-resulted in diagnostic sensitivity and specificity of 100% and 100%. The mobile device also successfully transmitted all whole-blood test results from a Rwandan clinic to a medical records database stored on the cloud. For all samples in the commercial panel, the device produced results in agreement with a leading ELISA test, including detection of weakly positive samples that were missed by existing rapid tests. The device operated autonomously with minimal user input, produced each result 10 times faster than benchtop ELISA, and consumed as little power as a mobile phone. CONCLUSIONS: A low-cost mobile device can perform a blood-based HIV serodiagnostic test with laboratory-level accuracy and real-time synchronization of patient health record data.

Commercialization of microfluidic point-of-care diagnostic devices.

A large part of the excitement behind microfluidics is in its potential for producing practical devices, but surprisingly few lab-on-a-chip based technologies have been successfully introduced into the market. Here, we review current work in commercializing microfluidic technologies, with a focus on point-of-care diagnostics applications. We will also identify challenges to commercialization, including lessons drawn from our experience in Claros Diagnostics. Moving forward, we discuss the need to strike a balance between achieving real-world impact with integrated devices versus design of novel single microfluidic components.

Analytical chemistry: sweet solution to sensing.

Glucose meters allow rapid and quantitative measurement of blood sugar levels for diabetes sufferers worldwide. Now a new method allows this proven technology to be used to quantify a much wider range of analytes.

Microfluidics-based diagnostics of infectious diseases in the developing world.

One of the great challenges in science and engineering today is to develop technologies to improve the health of people in the poorest regions of the world. Here we integrated new procedures for manufacturing, fluid handling and signal detection in microfluidics into a single, easy-to-use point-of-care (POC) assay that faithfully replicates all steps of ELISA, at a lower total material cost. We performed this 'mChip' assay in Rwanda on hundreds of locally collected human samples. The chip had excellent performance in the diagnosis of HIV using only 1 µl of unprocessed whole blood and an ability to simultaneously diagnose HIV and syphilis with sensitivities and specificities that rival those of reference benchtop assays. Unlike most current rapid tests, the mChip test does not require user interpretation of the signal. Overall, we demonstrate an integrated strategy for miniaturizing complex laboratory assays using microfluidics and nanoparticles to enable POC diagnostics and early detection of infectious diseases in remote settings.

Microfluidic CD4+ T-cell counting device using chemiluminescence-based detection.

This letter demonstrates a microfluidic platform for enumerating CD4+ T-lymphocytes from whole blood using chemiluminescence as a detection method. We microfabricated traps in a chamber and coated them with anti-CD4 antibody to isolate CD4+ T-cells. Based on cell surface-bound CD3 antibodies conjugated with horseradish peroxidase, incubation with chemiluminescent substrate produced a current in the photodetector that was proportional to the number of captured CD4+ T-cells. Analyzing 3 microL of whole blood, the platform exhibited high cell-capture efficiency and produced cell counts with high correlation to results obtained from flow cytometry. Compared to other lab-on-a-chip methods for CD4 counting, this method uses an instrument that requires no external light source and no image processing to produce a digitally displayed result only seconds after running the test.

Microfluidic point-of-care diagnostics for resource-poor environments.

Point-of-care (POC) diagnostics have tremendous potential to improve human health in remote and resource-poor settings. However, the design criteria for diagnostic tests appropriate in settings with limited infrastructure are unique and challenging. Here we present a custom optical reader which quantifies silver absorbance from heterogeneous immunoassays. The reader is simple, low-cost and suited for POC diagnostics.

Effect of volume- and time-based constraints on capture of analytes in microfluidic heterogeneous immunoassays.

Despite the prevalence of microfluidic-based heterogeneous immunoassays (where analytes in solution are captured on a solid surface functionalized with a capture molecule), there is incomplete understanding of how assay parameters influence the amount of captured analytes. This study presents computational results and corresponding experimental binding assays in which the capture of analytes is studied under variations in both mass transfer and surface binding, constrained by real-world assay conditions of finite sample volume, assay time, and capture area. Our results identify: 1) a "reagent-limited" regime which exists only under the constraints of finite sample volume and assay time; 2) a critical flow rate (e.g. 0.5 microL min(-1) under our assay conditions) to gain the maximum signal with the fastest assay time; 3) an increase in signal by using a short concentrated plug (e.g. 5 microL, 100 nM) rather than a long dilute plug (e.g. 50 microL, 10 nM) of sample; 4) the possibility of spending a considerable fraction of the assay time out of the reaction-limited regime. Overall, an improved understanding of fundamental physical processes may be particularly beneficial for the design of point-of-care assays, where volumes of reagents and available samples are limited, and the desired time-to-result short.

A microfabricated porous collagen-based scaffold as prototype for skin substitutes.

An important element of artificial skin is a tissue scaffold that allows for fast host regeneration. We present a microfabrication strategy, based on gelling collagen-based components inside a microfluidic device, that produces well-controlled pore sizes inside the scaffold. This strategy can produce finely patterned tissue scaffolds of clinically relevant dimensions suitable for surgical handling. Compared to porous collagen-based sponges produced by lyophilization, microfabricated tissue scaffolds preserve the fibrous structure and ligand density of natural occurring collagen. A fibroblast migration assay revealed fast cellular migration through the pores, which is desired for rapid tissue ingrowth. Finally, we also demonstrate a strategy to use this microfabrication technique to build anatomically accurate, multi-component skin substitutes in a cost-effective manner.

Lab-on-a-chip devices for global health: past studies and future opportunities.

A rapidly emerging field in lab-on-a-chip (LOC) research is the development of devices to improve the health of people in developing countries. In this review, we identify diseases that are most in need of new health technologies, discuss special design criteria for LOC devices to be deployed in a variety of resource-poor settings, and review past research into LOC devices for global health. We focus mainly on diagnostics, the nearest-term application in this field.