Prior activation state shapes the microglia response to antihuman TREM2 in a mouse model of Alzheimer's disease.

Triggering receptor expressed on myeloid cells 2 (TREM2) sustains microglia response to brain injury stimuli including apoptotic cells, myelin damage, and amyloid ß (Aß). Alzheimer's disease (AD) risk is associated with the TREM2R47H variant, which impairs ligand binding and consequently microglia responses to Aß pathology. Here, we show that TREM2 engagement by the mAb hT2AB as surrogate ligand activates microglia in 5XFAD transgenic mice that accumulate Aß and express either the common TREM2 variant (TREM2CV) or TREM2R47H scRNA-seq of microglia from TREM2CV-5XFAD mice treated once with control hIgG1 exposed four distinct trajectories of microglia activation leading to disease-associated (DAM), interferon-responsive (IFN-R), cycling (Cyc-M), and MHC-II expressing (MHC-II) microglia types. All of these were underrepresented in TREM2R47H-5XFAD mice, suggesting that TREM2 ligand engagement is required for microglia activation trajectories. Moreover, Cyc-M and IFN-R microglia were more abundant in female than male TREM2CV-5XFAD mice, likely due to greater Aß load in female 5XFAD mice. A single systemic injection of hT2AB replenished Cyc-M, IFN-R, and MHC-II pools in TREM2R47H-5XFAD mice. In TREM2CV-5XFAD mice, however, hT2AB brought the representation of male Cyc-M and IFN-R microglia closer to that of females, in which these trajectories had already reached maximum capacity. Moreover, hT2AB induced shifts in gene expression patterns in all microglial pools without affecting representation. Repeated treatment with a murinized hT2AB version over 10 d increased chemokines brain content in TREM2R47H-5XFAD mice, consistent with microglia expansion. Thus, the impact of hT2AB on microglia is shaped by the extent of TREM2 endogenous ligand engagement and basal microglia activation.

Subcutaneous Levodopa Infusion for Parkinson's Disease: 1-Year Data from the Open-Label BeyoND Study.

BACKGROUND: Continuous, subcutaneous (SC) levodopa/carbidopa infusion with ND0612 is under development as a treatment for patients with Parkinson's disease (PD) and motor fluctuations. OBJECTIVE: Evaluate 1-year safety data. METHODS: BeyoND is an open-label study evaluating the long-term safety of two ND0612 dosing regimens. RESULTS: Of the 214 enrolled patients (24-hour SC infusion: n = 90; 16-hour SC infusion: n = 124), 120 (56%) completed 12 months of treatment. Leading causes for study discontinuation were consent withdrawal (19.6%) and adverse events (17.3%). Rates of discontinuation were reduced from 49% to 29% after a protocol revision and retraining. Systemic safety was typical for PD patients treated with levodopa/carbidopa. Most patients experienced infusion site reactions, particularly nodules (30.8%) and hematoma (25.2%), which were judged mostly mild to moderate and led to discontinuation in only 10.3% of the participants. CONCLUSIONS: Subcutaneous levodopa/carbidopa continuous infusion with ND0612 is generally safe, with typical infusion site reactions for SC delivery as the main adverse event. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Hydration forces between aligned DNA helices undergoing B to A conformational change: In-situ X-ray fiber diffraction studies in a humidity and temperature controlled environment.

Hydration forces between DNA molecules in the A- and B-Form were studied using a newly developed technique enabling simultaneous in situ control of temperature and relative humidity. X-ray diffraction data were collected from oriented calf-thymus DNA fibers in the relative humidity range of 98%-70%, during which DNA undergoes the B- to A-form transition. Coexistence of both forms was observed over a finite humidity range at the transition. The change in DNA separation in response to variation in humidity, i.e. change of chemical potential, led to the derivation of a force-distance curve with a characteristic exponential decay constant of∼2Å for both A- and B-DNA. While previous osmotic stress measurements had yielded similar force-decay constants, they were limited to B-DNA with a surface separation (wall-to-wall distance) typically>5Å. The current investigation confirms that the hydration force remains dominant even in the dry A-DNA state and at surface separation down to∼1.5Å, within the first hydration shell. It is shown that the observed chemical potential difference between the A and B states could be attributed to the water layer inside the major and minor grooves of the A-DNA double helices, which can partially interpenetrate each other in the tightly packed A phase. The humidity-controlled X-ray diffraction method described here can be employed to perform direct force measurements on a broad range of biological structures such as membranes and filamentous protein networks.

Inhibition of secreted frizzled-related protein 5 improves glucose metabolism.

Elucidating the role of secreted frizzled-related protein 5 (SFRP5) in metabolism and obesity has been complicated by contradictory findings when knockout mice were used to determine metabolic phenotypes. By overexpressing SFRP5 in obese, prediabetic mice we consistently observed elevated hyperglycemia and glucose intolerance, supporting SFRP5 as a negative regulator of glucose metabolism. Accordingly, Sfrp5 mRNA expression analysis of both epididymal and subcutaneous adipose depots of mice indicated a correlation with obesity. Thus, we generated a monoclonal antibody (mAb) against SFRP5 to ascertain the effect of SFRP5 inhibition in vivo. Congruent with SFRP5 overexpression worsening blood glucose levels and glucose intolerance, anti-SFRP5 mAb therapy improved these phenotypes in vivo. The results from both the overexpression and mAb inhibition studies suggest a role for SFRP5 in glucose metabolism and pancreatic ß-cell function and thus establish the use of an anti-SFRP5 mAb as a potential approach to treat type 2 diabetes.

Essential parameters for structural analysis and dereplication by (1)H NMR spectroscopy.

The present study demonstrates the importance of adequate precision when reporting the δ and J parameters of frequency domain (1)H NMR (HNMR) data. Using a variety of structural classes (terpenoids, phenolics, alkaloids) from different taxa (plants, cyanobacteria), this study develops rationales that explain the importance of enhanced precision in NMR spectroscopic analysis and rationalizes the need for reporting Δδ and ΔJ values at the 0.1-1 ppb and 10 mHz level, respectively. Spectral simulations paired with iteration are shown to be essential tools for complete spectral interpretation, adequate precision, and unambiguous HNMR-driven dereplication and metabolomic analysis. The broader applicability of the recommendation relates to the physicochemical properties of hydrogen ((1)H) and its ubiquity in organic molecules, making HNMR spectra an integral component of structure elucidation and verification. Regardless of origin or molecular weight, the HNMR spectrum of a compound can be very complex and encode a wealth of structural information that is often obscured by limited spectral dispersion and the occurrence of higher order effects. This altogether limits spectral interpretation, confines decoding of the underlying spin parameters, and explains the major challenge associated with the translation of HNMR spectra into tabulated information. On the other hand, the reproducibility of the spectral data set of any (new) chemical entity is essential for its structure elucidation and subsequent dereplication. Handling and documenting HNMR data with adequate precision is critical for establishing unequivocal links between chemical structure, analytical data, metabolomes, and biological activity. Using the full potential of HNMR spectra will facilitate the general reproducibility for future studies of bioactive chemicals, especially of compounds obtained from the diversity of terrestrial and marine organisms.

Creating a more strategic small molecule biophysical hit characterization workflow.

To confirm target engagement of hits from our high-throughput screening efforts, we ran biophysical assays on several hundreds of hits from 15 different high-throughput screening campaigns. Analyzing the biophysical assay results from these screening campaigns led us to conclude that we could be more strategic in our biophysical analysis of hits by first confirming activity in a thermal shift assay (TSA) and then confirming activity in either a surface plasmon resonance (SPR) assay or a temperature-related intensity change (TRIC) assay. To understand how this new workflow shapes the quality of the final hits, we compared TSA/SPR or TSA/TRIC confirmed and unconfirmed hits to one another using four measures of compound quality: quantitative estimate of drug-likeness (QED), Pan-Assay Interference Compounds (PAINS), promiscuity, and aqueous solubility. In general, we found that the biophysically confirmed hits performed better in the compound quality metrics than the unconfirmed hits, demonstrating that our workflow not only confirmed target engagement of the hits but also enriched for higher quality hits.

AMG 509 (Xaluritamig), an Anti-STEAP1 XmAb 2+1 T-cell Redirecting Immune Therapy with Avidity-Dependent Activity against Prostate Cancer.

The tumor-associated antigen STEAP1 is a potential therapeutic target that is expressed in most prostate tumors and at increased levels in metastatic castration-resistant prostate cancer (mCRPC). We developed a STEAP1-targeted XmAb 2+1 T-cell engager (TCE) molecule, AMG 509 (also designated xaluritamig), that is designed to redirect T cells to kill prostate cancer cells that express STEAP1. AMG 509 mediates potent T cell-dependent cytotoxicity of prostate cancer cell lines in vitro and promotes tumor regression in xenograft and syngeneic mouse models of prostate cancer in vivo. The avidity-driven activity of AMG 509 enables selectivity for tumor cells with high STEAP1 expression compared with normal cells. AMG 509 is the first STEAP1 TCE to advance to clinical testing, and we report a case study of a patient with mCRPC who achieved an objective response on AMG 509 treatment. SIGNIFICANCE: Immunotherapy in prostate cancer has met with limited success due to the immunosuppressive microenvironment and lack of tumor-specific targets. AMG 509 provides a targeted immunotherapy approach to engage a patient's T cells to kill STEAP1-expressing tumor cells and represents a new treatment option for mCRPC and potentially more broadly for prostate cancer. See related commentary by Hage Chehade et al., p. 20. See related article by Kelly et al., p. 76. This article is featured in Selected Articles from This Issue, p. 5.

Safety and efficacy of continuous subcutaneous levodopa-carbidopa infusion (ND0612) for Parkinson's disease with motor fluctuations (BouNDless): a phase 3, randomised, double-blind, double-dummy, multicentre trial.

BACKGROUND: Conventional oral levodopa therapy for the treatment of Parkinson's disease can be associated with variations in plasma concentrations. Levodopa infusion strategies might provide more consistent drug delivery and fewer motor fluctuations. We aimed to assess the safety and efficacy of a continuous 24 h/day subcutaneous infusion of ND0612 (a levodopa-carbidopa solution) compared with oral immediate-release levodopa-carbidopa for the treatment of motor fluctuations in people with Parkinson's disease. METHODS: We conducted a phase 3, randomised, double-blind, double-dummy, active-controlled, multicentre trial at 117 academic and community neurology sites in 16 countries, including in Europe, Israel, and the USA. Eligible participants were men and women aged 30 years or older with a diagnosis of Parkinson's disease (Hoehn and Yahr stage ≤3 in the on state) who experienced at least 2·5 h/day of off time. Participants underwent an open-label run-in phase (<12 weeks), during which time optimal regimens were established for both oral immediate-release levodopa-carbidopa and for 24 h/day subcutaneous ND0612 infusion (levodopa-carbidopa 60·0/7·5 mg/mL), with supplemental oral levodopa-carbidopa if needed. Participants were then randomly assigned (1:1) to 12 weeks of double-blind treatment with their optimised regimen of either subcutaneous ND0612 or oral levodopa-carbidopa, with matching oral or subcutaneous placebo given as required to maintain blinding. Randomisation was done via an interactive web response system, stratified by region, using a permuted block schedule. Participants, study partners, treating investigators, study site personnel, and the sponsor were masked to treatment group allocation. The primary efficacy endpoint was the change from baseline (ie, time of randomisation, when all patients were receiving an optimised open-label ND0612 regimen) to end of the double-blind phase in total daily on time without troublesome dyskinesia, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, NCT04006210, and is complete. FINDINGS: Between Sept 30, 2019, and April 8, 2022, 381 participants were enrolled, of whom 259 (68%) were randomly assigned, 128 (49%) to subcutaneous ND0612 and 131 (51%) to oral levodopa-carbidopa. 243 (94%) participants completed the study. Treatment with subcutaneous ND0612 provided an additional 1·72 h (95% CI 1·08 to 2·36) of on time without troublesome dyskinesia compared with oral levodopa-carbidopa (change from baseline of -0·48 h [-0·94 to -0·02] with subcutaneous ND0612 vs -2·20 h [-2·65 to -1·74] with oral levodopa-carbidopa; p<0·0001). Significant treatment differences favouring subcutaneous ND0612 were also found in the first four of nine prespecified hierarchical outcomes of daily off time (-1·40 h [95% CI -1·99 to -0·80]), Movement Disorders Society-Unified Parkinson's Disease Rating Scale part II scores (-3·05 [-4·28 to -1·81]), Patients Global Impression of Change (odds ratio [OR] 5·31 [2·67 to 10·58]), and Clinical Global Impression of Improvement (OR 7·23 [3·57 to 14·64]). Hierarchical testing ended after the fourth secondary endpoint. Adverse events were reported by 287 (89%) of 322 participants during open-label ND0612 optimisation, and by 103 (80%) of 128 in the ND0612 group and 97 (74%) of 131 in the oral levodopa-carbidopa group during the double-blind phase. The most common adverse events were infusion-site reactions (266 [83%] participants during open-label ND0612, and 73 [57%] in the ND0612 group vs 56 [43%] in the oral levodopa-carbidopa group during the double-blind phase), most of which were mild. Serious adverse events in four participants in the ND0612 group were related to study treatment (infusion-site cellulitis [n=2], infusion-site abscess and infusion-site ulcer [n=1]; and paraesthesia and peripheral sensorimotor neuropathy [n=1]). One participant in the ND0612 group died during the double-blind phase, but the death was not related to study treatment (fall leading to traumatic brain injury). INTERPRETATION: Results of this phase 3 study showed that subcutaneous ND0612 used in combination with oral immediate-release levodopa-carbidopa increased on time without troublesome dyskinesia and reduced off time, with a favourable benefit-risk profile. ND0612 might offer a safe and efficacious subcutaneous levodopa infusion approach to managing motor fluctuations in people with Parkinson's disease. The ongoing open-label extension phase will provide further information on the long-term efficacy and safety of treatment. FUNDING: NeuroDerm.

The pharmacokinetics of continuous subcutaneous levodopa/carbidopa infusion: Findings from the ND0612 clinical development program.

Background: While treatment with levodopa remains the cornerstone of Parkinson's disease (PD) management, chronic oral therapy is often associated with the development of motor complications, that correlate to fluctuating levodopa plasma concentrations, limiting its clinical utility. Continuous infusion is considered to be the optimal delivery route for treating PD patients with motor fluctuations, but current infusion systems require invasive surgery. Subcutaneous infusion of (SC) levodopa has the potential to provide a better tolerated and more convenient route of continuous levodopa delivery. ND0612 is in development as a combination product providing continuous levodopa/carbidopa via a minimally invasive, subcutaneous delivery system for PD patients experiencing motor response fluctuations. We present pharmacokinetic results from a series of studies that analyzed plasma concentrations after SC levodopa delivery with ND0612 to inform the clinical development program. Methods: We performed a series of six Phase I and II studies to characterize the pharmacokinetics of levodopa and carbidopa derived from ND0612 infusion with/without adjunct oral therapy of the same ingredients. These studies were conducted in healthy volunteers and in PD patients experiencing motor response fluctuations while on their current levodopa therapy regimen. Results: Taken together, the results demonstrate dose-proportionality dependent on rate of subcutaneous levodopa infusion leading to stable and sustained plasma concentrations of levodopa. Subcutaneous infusion of ND0612 administered with oral levodopa/carbidopa maintained near-constant, therapeutic levodopa plasma concentrations, thereby avoiding the troughs in levodopa plasma concentrations that are associated with OFF time in PD. The data generated in this series of studies also confirmed that a levodopa/carbidopa dose ratio of 8:1 would be the most reasonable choice for ND0612 development. Conclusions: This series of clinical pharmacokinetic studies have demonstrated that ND0612, administered continuously with a levodopa concentration of 60 mg/ml combined with carbidopa 7.5 mg/ml, and complemented with oral levodopa/carbidopa, is suitable for 24 h continuous administration in patients with PD. The stable plasma concentrations of levodopa achieved predict utility of ND0612 as a parenteral formulation for achieving clinically useful delivery of levodopa for PD patients.

ND0612 (levodopa/carbidopa for subcutaneous infusion) in patients with Parkinson's disease and motor response fluctuations: A randomized, placebo-controlled phase 2 study.

INTRODUCTION: ND0612 is a continuous, subcutaneous levodopa/carbidopa delivery system under development for patients with Parkinson's disease (PD) and motor fluctuations. METHODS: This was a randomized, placebo-controlled, double-blind, 2-period study evaluating the safety and pharmacokinetics of ND0612 in PD patients on an optimized oral levodopa regimen and experiencing ≥2 h/day of OFF time. During Period-1, patients received their current standard of care (SoC) levodopa/carbidopa and were randomized (2:1) to 14 days treatment with adjunct ND0612 (daily levodopa/carbidopa dose of 270/63 mg) or placebo infusion +SoC. During Period-2, 16 patients were randomized to receive 7 days treatment with ND0612 or ND0612 plus oral entacapone. Reduction in OFF time was analyzed as an exploratory measure using a futility design with a predefined margin of 1.6 h. RESULTS: ND0612 was well-tolerated; most patients experienced infusion site nodules (95% vs. 56% with placebo), which all resolved without sequelae. Patients treated with adjunct ND0612 during Period-1 avoided deep troughs in levodopa plasma levels and had a decreased fluctuation index versus placebo (1.6 ± 0.5 vs 3.1 ± 1.6 at end of Period-1, respectively). In Period-2, the coadministration of entacapone with continuous ND0612 SC infusion translated to an increase in mean levodopa AUC0-10h compared to baseline. Exploratory efficacy analysis of Period 1 showed mean ± SD OFF time reductions of -2.13 ± 2.24 [90%CI: -2.8, ∞] hours (p = 0.84 using H0 of µ0 ≤-1.6). CONCLUSION: Levodopa/carbidopa infusion with ND0612 was generally well-tolerated and resulted in reduced fluctuations in plasma levodopa concentrations when given with SoC oral levodopa. ND0612 met the efficacy endpoint for the futility design.

Rational selection of building blocks for the assembly of bispecific antibodies.

Bispecific antibodies, engineered to recognize two targets simultaneously, demonstrate exceptional clinical potential for the therapeutic intervention of complex diseases. However, these molecules are often composed of multiple polypeptide chains of differing sequences. To meet industrial scale productivity, enforcing the correct quaternary assembly of these chains is critical. Here, we describe Chain Selectivity Assessment (CSA), a high-throughput method to rationally select parental monoclonal antibodies (mAbs) to make bispecific antibodies requiring correct heavy/light chain pairing. By deploying CSA, we have successfully identified mAbs that exhibit a native preference toward cognate chain pairing that enables the production of hetero-IgGs without additional engineering. Furthermore, CSA also identified rare light chains (LCs) that permit positive binding of the non-cognate arm in the common LC hetero-IgGs, also without engineering. This rational selection of parental mAbs with favorable developability characteristics is critical to the successful development of bispecific molecules with optimal manufacturability properties.

Continuous Subcutaneous Levodopa Delivery for Parkinson's Disease: A Randomized Study.

BACKGROUND: ND0612 is a continuous, subcutaneous levodopa/carbidopa delivery system in development for patients with Parkinson's disease (PD) experiencing motor fluctuationsObjective:Evaluate the efficacy and safety of two ND0612 dosing regimens in patients with PD. METHODS: This was a 28-day open-label study (NCT02577523) in PD patients with ≥2.5 hours/day of OFF time despite optimized treatment. Patients were randomized to treatment with either a 24-hour infusion (levodopa/carbidopa dose of 720/90 mg) or a 14-hour 'waking-day' infusion (levodopa/carbidopa dose of 538/68 mg plus a morning oral dose of 150/15 mg). Supplemental oral doses of levodopa were permitted for patients in both groups if required. In-clinic assessments of OFF time (primary endpoint) and ON time with or without dyskinesia were determined by a blinded rater over 8 hours (normalized to 16 hours). RESULTS: A total of 38 patients were randomized and 33 (87%) completed the study. Compared to baseline, OFF time for the overall population was reduced by a least squares (LS) mean[95% CI] of 2.0[- 3.3, - 0.7] hours (p = 0.003). ON time with no/mild dyskinesia (no troublesome dyskinesia) was increased from baseline by a LS mean of 3.3[2.0, 4.6] hours (p < 0.0001), and ON time with moderate/severe dyskinesia was reduced by a LS mean of 1.2[- 1.8, - 0.5] hours (p≤0.001). Reduction in OFF time was larger in the 24-hour group (- 2.8[- 4.6, - 0.9] hours; p = 0.004) than in the 14-hour group (- 1.3[- 3.1, 0.5] hours; p = 0.16). Complete resolution of OFF time was observed in 42% (n = 8) of patients in the 24-hour group. Infusion site reactions were the most common adverse event. CONCLUSION: This study demonstrates the feasibility and safety of continuous subcutaneous delivery of levodopa as a treatment for PD and provides preliminary evidence of efficacy.

Determination of organic acids in Vaccinium berry standard reference materials.

Nine organic acids (citric acid, galacturonic acid, glycolic acid, isocitric acid, malic acid, oxalic acid, quinic acid, shikimic acid, and tartaric acid) and two anions (phosphate and sulfate) were determined in a suite of Vaccinium berry-containing dietary supplement standard reference materials (SRMs). Following solvent extraction, three independent methods were utilized in the quantification of these compounds. The first method involved reversed-phase liquid chromatography with ultraviolet absorbance detection at 210 nm and isotope dilution mass spectrometry. The second method utilized ion chromatography with conductivity detection. Finally, gas chromatography with isotope dilution mass spectrometry detection was used following derivatization with N-methyl-N-trifluoroacetamide (MSTFA). The combined data from these methods was used for the assignment of organic acid levels in the seven candidate SRMs.

Chromatographic methods for the quantification of free and chelated gadolinium species in MRI contrast agent formulations.

Speciation measurements of gadolinium in liposomal MRI contrast agents (CAs) are complicated by the presence of emulsifiers, surfactants, and therapeutic agents in the formulations. The present paper describes two robust, hyphenated chromatography methods for the separation and quantification of gadolinium in nanoemulsion-based CA formulations. Three potential species of gadolinium, free gadolinium ion, gadolinium chelated by diethylenetriamine pentaacetic acid, and gadolinium chelated by 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-N-diethylenetriaminepentaacetic acid, were present in the CA formulations. The species were separated by reversed-phase chromatography (reversed phase high-performance liquid chromatography, RP-HPLC) or by high-pressure size-exclusion chromatography (HPSEC). For RP-HPLC, fluorescence detection and post-column online isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) were used to measure the amount of gadolinium in each species. Online ID-ICP-MS and species-specific isotope dilution (SID)-ICP-MS were used in combination with the HPSEC column. The results indicated that some inter-species conversions and degradation had occurred within the samples and that SID-ICP-MS should be used to provide the most reliable measurements of total and speciated gadolinium. However, fluorescence and online ID-ICP-MS might usefully be applied as qualitative, rapid screening procedures for the presence of free gadolinium ions.

Engineered IL-21 Cytokine Muteins Fused to Anti-PD-1 Antibodies Can Improve CD8+ T Cell Function and Anti-tumor Immunity.

Inhibitors that block the programmed cell death-1 (PD-1) pathway can potentiate endogenous antitumor immunity and have markedly improved cancer survival rates across a broad range of indications. However, these treatments work for only a minority of patients. The efficacy of anti-PD-1 inhibitors may be extended by cytokines, however, the incorporation of cytokines into therapeutic regimens has significant challenges. In their natural form when administered as recombinant proteins, cytokine treatments are often associated with low response rates. Most cytokines have a short half-life which limits their exposure and efficacy. In addition, cytokines can activate counterregulatory pathways, in the case of immune-potentiating cytokines this can lead to immune suppression and thereby diminish their potential efficacy. Improving the drug-like properties of natural cytokines using protein engineering can yield synthetic cytokines with improved bioavailability and tissue targeting, allowing for enhanced efficacy and reduced off-target effects. Using structure guided engineering we have designed a novel class of antibody-cytokine fusion proteins consisting of a PD-1 targeting antibody fused together with an interleukin-21 (IL-21) cytokine mutein. Our bifunctional fusion proteins can block PD-1/programmed death-ligand 1 (PD-L1) interaction whilst simultaneously delivering IL-21 cytokine to PD-1 expressing T cells. Targeted delivery of IL-21 can improve T cell function in a manner that is superior to anti-PD-1 monotherapy. Fusion of engineered IL-21 variants to anti-PD1 antibodies can improve the drug-like properties of IL-21 cytokine leading to improved cytokine serum half-life allowing for less frequent dosing. In addition, we show that targeted delivery of IL-21 can minimize any potential detrimental effect on local antigen-presenting cells. A highly attenuated IL-21 mutein variant (R9E:R76A) fused to a PD-1 antibody provides protection in a humanized mouse model of cancer that is refractory to anti-PD-1 monotherapy. Collectively, our preclinical data demonstrate that this approach may improve upon and extend the utility of anti-PD-1 therapeutics currently in the clinic.

Characterization of a Novel FLT3 BiTE Molecule for the Treatment of Acute Myeloid Leukemia.

Despite advances in the treatment of acute myeloid leukemia (AML), novel therapies are needed to induce deeper and more durable clinical response. Bispecific T-cell Engager (BiTE) molecules, which redirect patient T cells to lyse tumor cells, are a clinically validated modality for hematologic malignancies. Due to broad AML expression and limited normal tissue expression, fms-related tyrosine kinase 3 (FLT3) is proposed to be an optimal BiTE molecule target. Expression profiling of FLT3 was performed in primary AML patient samples and normal hematopoietic cells and nonhematopoietic tissues. Two novel FLT3 BiTE molecules, one with a half-life extending (HLE) Fc moiety and one without, were assessed for T-cell-dependent cellular cytotoxicity (TDCC) of FLT3-positive cell lines in vitro, in vivo, and ex vivo FLT3 protein was detected on the surface of most primary AML bulk and leukemic stem cells but only a fraction of normal hematopoietic stem and progenitor cells. FLT3 protein detected in nonhematopoietic cells was cytoplasmic. FLT3 BiTE molecules induced TDCC of FLT3-positive cells in vitro, reduced tumor growth and increased survival in AML mouse models in vivo Both molecules exhibited reproducible pharmacokinetic and pharmacodynamic profiles in cynomolgus monkeys in vivo, including elimination of FLT3-positive cells in blood and bone marrow. In ex vivo cultures of primary AML samples, patient T cells induced TDCC of FLT3-positive target cells. Combination with PD-1 blockade increased BiTE activity. These data support the clinical development of an FLT3 targeting BiTE molecule for the treatment of AML.

Targeting Multiple Myeloma with AMG 424, a Novel Anti-CD38/CD3 Bispecific T-cell-recruiting Antibody Optimized for Cytotoxicity and Cytokine Release.

PURPOSE: Despite advances in the treatment of multiple myeloma, new therapies are needed to induce more profound clinical responses. T-cell-redirected lysis triggered by bispecific antibodies recruiting T cells to cancer cells is a clinically validated mechanism of action against hematologic malignancies and CD38 is a tumor-associated antigen with near-universal expression in multiple myeloma. Thus, an anti-CD38/CD3 bispecific T-cell-recruiting antibody has the potential to be an effective new therapeutic for multiple myeloma. EXPERIMENTAL DESIGN: Anti-CD38/CD3 XmAb T-cell-recruiting antibodies with different affinities for CD38 and CD3 were assessed in vitro and in vivo for their redirected T-cell lysis activity against cancer cell lines, their lower levels of cytokine release, and their potency in the presence of high levels of soluble CD38. Select candidates were further tested in cynomolgus monkeys for B-cell depletion and cytokine release properties. RESULTS: AMG 424 was selected on the basis of its ability to kill cancer cells expressing high and low levels of CD38 in vitro and trigger T-cell proliferation, but with attenuated cytokine release. In vivo, AMG 424 induces tumor growth inhibition in bone marrow-invasive mouse cancer models and the depletion of peripheral B cells in cynomolgus monkeys, without triggering excessive cytokine release. The activity of AMG 424 against normal immune cells expressing CD38 is also presented. CONCLUSIONS: These findings support the clinical development of AMG 424, an affinity-optimized T-cell-recruiting antibody with the potential to elicit significant clinical activity in patients with multiple myeloma.

Development of a fluorescence-based assay to screen antiviral drugs against Kaposi's sarcoma associated herpesvirus.

Tumors associated with Kaposi's sarcoma-associated herpesvirus infection include Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. Virtually all of the tumor cells in these cancers are latently infected and dependent on the virus for survival. Latent viral proteins maintain the viral genome and are required for tumorigenesis. Current prevention and treatment strategies are limited because they fail to specifically target the latent form of the virus, which can persist for the lifetime of the host. Thus, targeting latent viral proteins may prove to be an important therapeutic modality for existing tumors as well as in tumor prevention by reducing latent virus load. Here, we describe a novel fluorescence-based screening assay to monitor the maintenance of the Kaposi's sarcoma-associated herpesvirus genome in B lymphocyte cell lines and to identify compounds that induce its loss, resulting in tumor cell death.

Design and outcomes of the Patient Centered Outcomes Research Institute coronary heart disease cohort study.

BACKGROUND: The Patient Centered Outcomes Research Institute (PCORI) established Clinical Data Research Networks (CDRNs) to support pragmatic research. The objective was to electronically identify, recruit, and survey coronary heart disease (CHD) patients and describe their characteristics, health status, and willingness to participate in future research. METHODS: We developed a computable phenotype and assembled CHD patients 30 years or older and had visits or hospitalizations between 2009 and 2015. A sample of patients was surveyed between August 2014 and September 2015. Survey administration included the following methods: face-to-face, telephone, paper or web portal. Survey items covered broad domains including: health literacy and numeracy, and socio-demographics, physical and mental health, health behaviors, access to medical care, and willingness to participate in future research. RESULTS: Of 5517 approached patients, 2605 completed the survey. Participants were mostly white (∼88%), male (68%) and had a median age of 69 years (interquartile range [IQR] 61-76 years). Most respondents' health literacy and numeracy were adequate (83.2% and 84.3%, respectively). Only 4% of respondents reported that their overall health or physical health was excellent. The majority (∼58%) reported that their health was good or very good, while 40% reported that their general and physical health were fair or poor. The majority reported that their quality of life was good to excellent (81%). Limitations in physical health and function were common, including often/always having fatigue (25%), pain (38.7%), or sleep difficulty (19.7%). A patient sample (n = 1936) was provided with a trial summary which would randomize their aspirin dose; and 63% reported that they would consider participating. CONCLUSION: Many patients with CHD had limitations in physical health. However, the majority reported a good or excellent quality of life.

Novel protein therapeutic joint retention strategy based on collagen-binding Avimers.

Designing drugs to treat diseases associated with articular joints, particularly those targeting chondrocytes, is challenging due to unique local environmental constraints including the avascular nature of cartilage, the absence of a closed joint compartment, and a highly cross-linked extracellular matrix. In an effort to address these challenges, we developed a novel strategy to prolong residence time of intra-articularly administered protein therapeutics. Avimer domains are naturally found in membrane polypeptides and mediate diverse protein-protein interactions. Screening of a phage Avimer domain library led to identification of several low affinity type II collagen-binding Avimers. Following several rounds of mutagenesis and reselection, these initial hits were transformed to high affinity, selective type II collagen-binding Avimers. One such Avimer (M26) persisted in rat knees for at least 1 month following intra-articular administration. Fusion of this Avimer to a candidate therapeutic payload, IL-1Ra, yielded a protein construct which simultaneously bound to type II collagen and to IL-1 receptor. In vitro, IL-1Ra_M26 bound selectively to cartilage explants and remained associated even after extensive washing. Binding appeared to occur preferentially to pericellular regions surrounding chondrocytes. An acute intra-articular IL-1-induced IL-6 challenge rat model was employed to assess in vivo pharmacodynamics. Whereas both IL-1Ra_M26 and native IL-1Ra inhibited IL-6 output when co-administered with the IL-1 challenge, only IL-1Ra_M26 inhibited when administered 1 week prior to IL-1 challenge. Collagen-binding Avimers thus represent a promising strategy for enhancing cartilage residence time of protein therapeutics. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1238-1247, 2018.