Safety and efficacy of voxelotor in pediatric patients with sickle cell disease aged 4 to 11 years.

BACKGROUND: Sickle cell disease (SCD) is a devastating, multisystemic disorder that affects millions of people worldwide. The earliest clinical manifestations of SCD can affect infants as young as 6 months of age, and pediatric patients are at risk for acute and life-threatening complications. Early intervention with treatments that target the underlying pathophysiological mechanism of SCD, sickle hemoglobin (HbS) polymerization, are expected to slow disease progression and circumvent disease-associated morbidity and mortality. PROCEDURE: The HOPE-KIDS 1 trial (NCT02850406) is an ongoing four-part, phase 2a, open-label, single- and multiple-dose study to evaluate the pharmacokinetics, efficacy, and safety of voxelotor-a first-in-class HbS polymerization inhibitor-in patients aged 6 months to 17 years with SCD. Initial findings from a cohort of 45 patients aged 4 to 11 years who received voxelotor treatment for up to 48 weeks are reported. RESULTS: Hemoglobin (Hb) response, defined as a >1.0 g/dl increase from baseline, was achieved at week 24 by 47% (n = 16/34) of patients with Hb measurements at baseline and week 24. At week 24, 35% (n = 12/34) and 21% (n = 7/34) of patients had a >1.5 g/dl increase and a >2.0 g/dl increase from baseline in Hb concentration, respectively. Concurrent improvements in hemolytic markers were observed. Voxelotor was well tolerated in this young cohort, with no newly emerging safety signals. CONCLUSIONS: Based on its mechanism as an HbS polymerization inhibitor, voxelotor improves Hb levels and markers of hemolysis and has the potential to mitigate SCD-related complications; these results support its use in patients aged ≥4 years.

Baseline asthma burden, comorbidities, and biomarkers in omalizumab-treated patients in PROSPERO.

BACKGROUND: Patients included in clinical trials do not necessarily reflect the real-world population. OBJECTIVE: To understand the characteristics, including disease and comorbidity burden, of patients with asthma receiving omalizumab in a real-world setting. METHODS: The Prospective Observational Study to Evaluate Predictors of Clinical Effectiveness in Response to Omalizumab (PROSPERO) was a US-based, multicenter, single-arm, and prospective study. Patients (≥12 years of age) with allergic asthma initiating omalizumab treatment based on physician-assessed need were included and followed for 12 months. Exacerbations, health care use, adverse events, and Asthma Control Test (ACT) scores were assessed monthly. Biomarkers (blood eosinophils, fractional exhaled nitric oxide, and periostin) were evaluated and patient-reported outcomes (Asthma Quality of Life Questionnaire for 12 Years and Older [AQLQ+12] and Work Productivity and Activity Impairment: Asthma questionnaire [WPAI:Asthma]) were completed at baseline and months 6 and 12. The Mini Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ) was completed at baseline and 12 months. RESULTS: Most of the 806 enrollees (91.4%) were adults (mean age 47.3 years, SD 17.4), white (70.3%), and female (63.5%). Allergic comorbidity was frequently reported (84.2%), as were hypertension (35.5%) and depression (22.1%). In the 12 months before study entry, 22.1% of patients reported at least 1 asthma-related hospitalization, 60.7% reported at least 2 exacerbations, and 83.3% reported ACT scores no higher than 19 (uncontrolled asthma). Most patients had low biomarker levels based on prespecified cut-points. Baseline mean patient-reported outcome scores were 4.0 (SD 1.4) for AQLQ+12, 2.7 (SD 1.4) for MiniRQLQ, and 47.7 (SD 28.9) for WPAI:Asthma percentage of activity impairment and 33.5 (SD 28.7) for percentage of overall work impairment. CONCLUSION: The population initiating omalizumab in PROSPERO reported poorly controlled asthma and a substantial disease burden. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01922037.

Overcoming key technological challenges in using mass spectrometry for mapping cell surfaces in tissues.

Plasma membranes form a critical biological interface between the inside of every cell and its external environment. Their roles in multiple key cellular functions make them important drug targets. However the protein composition of plasma membranes in general is poorly defined as the inherent properties of lipid embedded proteins, such as their hydrophobicity, low abundance, poor solubility and resistance to digestion and extraction makes them difficult to isolate, solubilize, and identify on a large scale by traditional mass spectrometry methods. Here we describe some of the significant advances that have occurred over the past ten years to address these challenges including: i) the development of new and improved membrane isolation techniques via either subfractionation or direct labeling and isolation of plasma membranes from cells and tissues; ii) modification of mass spectrometry methods to adapt to the hydrophobic nature of membrane proteins and peptides; iii) improvements to digestion protocols to compensate for the shortage of trypsin cleavage sites in lipid-embedded proteins, particularly multi-spanning proteins, and iv) the development of numerous bioinformatics tools which allow not only the identification and quantification of proteins, but also the prediction of membrane protein topology, membrane post-translational modifications and subcellular localization. This review emphasis the importance and difficulty of defining cells in proper patho- and physiological context to maintain the in vivo reality. We focus on how key technological challenges associated with the isolation and identification of cell surface proteins in tissues using mass spectrometry are being addressed in order to identify and quantify a comprehensive plasma membrane for drug and target discovery efforts.

Designed auto-assembly of nanostreptabodies for rapid tissue-specific targeting in vivo.

Molecular medicine can benefit greatly from antibodies that deliver therapeutic and imaging agents to select organs and diseased tissues. Yet the development of complex and defined composite nanostructures remains a challenge that requires both designed stoichiometric assembly and superior in vivo testing ability. Here, we generate nanostructures called nanostreptabodies by controlled sequential assembly of biotin-engineered antibody fragments on a streptavidin scaffold with a defined capacity for additional biotinylated payloads such as other antibodies to create bispecific antibodies as well as organic and non-organic moieties. When injected intravenously, these novel and stable nanostructures exhibit exquisite targeting with tissue-specific imaging and delivery, including rapid transendothelial transport that enhances tissue penetration. This "tinkertoy construction" strategy provides a very flexible and efficient way to link targeting vectors with reporter and/or effector agents, thereby providing virtually endless combinations potentially useful for multipurpose molecular and functional imaging in vivo as well as therapies.

Enhancing identifications of lipid-embedded proteins by mass spectrometry for improved mapping of endothelial plasma membranes in vivo.

Lipid membranes structurally define the outer surface and internal organelles of cells. The multitude of proteins embedded in lipid bilayers are clearly functionally important, yet they remain poorly defined. Even today, integral membrane proteins represent a special challenge for current large scale shotgun proteomics methods. Here we used endothelial cell plasma membranes isolated directly from lung tissue to test the effectiveness of four different mass spectrometry-based methods, each with multiple replicate measurements, to identify membrane proteins. In doing so, we substantially expanded this membranome to 1,833 proteins, including >500 lipid-embedded proteins. The best method combined SDS-PAGE prefractionation with trypsin digestion of gel slices to generate peptides for seamless and continuous two-dimensional LC/MS/MS analysis. This three-dimensional separation method outperformed current widely used two-dimensional methods by significantly enhancing protein identifications including single and multiple pass transmembrane proteins; >30% are lipid-embedded proteins. It also profoundly improved protein coverage, sensitivity, and dynamic range of detection and substantially reduced the amount of sample and the number of replicate mass spectrometry measurements required to achieve 95% analytical completeness. Such expansion in comprehensiveness requires a trade-off in heavy instrument time but bodes well for future advancements in truly defining the ever important membranome with its potential in network-based systems analysis and the discovery of disease biomarkers and therapeutic targets. This analytical strategy can be applied to other subcellular fractions and should extend the comprehensiveness of many future organellar proteomics pursuits.

Characteristics of Peanut Allergy Diagnosis in a US Health Care Claims Database (2011-2017).

BACKGROUND: Peanut allergy is the most common food allergy among children. Studies assessing the burden of peanut allergy in a real-world setting are limited. OBJECTIVE: To estimate annual incidence and prevalence of peanut allergy cases among children aged 4 to 17 years and assess severe reaction and associated health care utilization rates. METHODS: Patient longitudinal data between January 2011 and December 2017 from a geographically and payer-type representative US health care claims database were used. Peanut allergy cases were identified using diagnostic codes and/or services indicating peanut-allergy-associated severe reactions/anaphylaxis. Estimated annual incidence was defined as peanut-allergic births as a proportion of all 1-year-olds and adjusted for less than 100% data set capture, undercoding, patient underpresenting rates, and spontaneous outgrowth. Prevalence was calculated on the basis of incidence. To assess rates of severe reactions to peanut and associated health care utilization, the cohort of 720,490 peanut allergy cases identified in 2011 was evaluated over a 6-year period from 2011 to 2017. RESULTS: Annual incidence increased from 1.7% to 5.2% between 2001 and 2017. Estimated prevalence in 4- to 17-year-olds was 1.25 million (2.2%) in 2017. Atopic comorbidities (asthma, 60.8%; atopic dermatitis, 61.7%) and other food allergies (35.3%) were common. Severe reactions (≥1) were observed in more than half (n = 399,806) the patients, and 37.9% were triggered by an accidental exposure. One in 5 patients (n = 144,883) visited the emergency department due to peanut exposure. CONCLUSIONS: Claims data suggest that the incidence and prevalence of peanut allergy in the United States may be increasing. Estimated severe reaction rates and health care utilization were high, suggesting that the burden of peanut allergy may be considerable.

Omalizumab Effectiveness by Biomarker Status in Patients with Asthma: Evidence From PROSPERO, A Prospective Real-World Study.

BACKGROUND: Omalizumab has demonstrated efficacy in clinical trials of patients with asthma, but real-world data are needed. OBJECTIVE: To assess outcomes after omalizumab initiation in patients with asthma in a real-world setting. METHODS: Patients aged 12 years and older with allergic asthma who were candidates for omalizumab on the basis of physician-assessed need were enrolled in a US-based, prospective, single-arm, 48-week multicenter study, the Prospective Observational Study to Evaluate Predictors of Clinical Effectiveness in Response to Omalizumab. Monthly assessments included exacerbations, health care utilization, asthma control test (ACT), and adverse events. At baseline, 6 months, and end of study, biomarkers (blood eosinophils and fractional exhaled nitric oxide) were collected and spirometry performed. RESULTS: Of 806 enrollees, 801 (99.4%) received omalizumab and 622 (77.2%) completed the study. The exacerbation rate significantly improved from a mean of 3.00 ± 3.28 in the 12 months before baseline to 0.78 ± 1.37 through month 12 (P < .001) and was similar in adults and adolescents; there was a reduction of 81.9% in the percentage of patients with 1 or more hospitalizations. Lung function remained generally unchanged. A mean improvement of 4.4 ± 4.9 in ACT scores was observed. Eighty-seven percent of patients were responders on the basis of clinical improvement in exacerbations, lung function, or ACT scores. Baseline biomarker status was associated with ACT scores and lung function improvement, but the magnitude of this improvement was not clinically relevant. No new safety signals emerged. CONCLUSIONS: Omalizumab initiation in patients with asthma resulted in improved exacerbation rates, reduced hospitalizations, and improved ACT scores compared with pretreatment values, regardless of biomarker status.

Label-free, normalized quantification of complex mass spectrometry data for proteomic analysis.

Replicate mass spectrometry (MS) measurements and the use of multiple analytical methods can greatly expand the comprehensiveness of shotgun proteomic profiling of biological samples. However, the inherent biases and variations in such data create computational and statistical challenges for quantitative comparative analysis. We developed and tested a normalized, label-free quantitative method termed the normalized spectral index (SI(N)), which combines three MS abundance features: peptide count, spectral count and fragment-ion (tandem MS or MS/MS) intensity. SI(N) largely eliminated variances between replicate MS measurements, permitting quantitative reproducibility and highly significant quantification of thousands of proteins detected in replicate MS measurements of the same and distinct samples. It accurately predicts protein abundance more often than the five other methods we tested. Comparative immunoblotting and densitometry further validate our method. Comparative quantification of complex data sets from multiple shotgun proteomics measurements is relevant for systems biology and biomarker discovery.

Chapter 8. Proteomic mapping of the vascular endothelium in vivo for vascular targeting.

The mapping and characterization of the vasculature using proteomics offers the opportunity to better understand the steps and molecular mechanisms involved in vascular development, and angiogenesis in particular. Proteomics has many key advantages over genomics, especially in directly determining protein expression. Such an approach offers researchers the opportunity to discover the proteins that make up the vasculature in an a priori manner facilitating the generation of hypothesis which can subsequently be validated by other methods. This chapter focuses on proteomic principles and methods, with a particular focus on their applications to characterizing the vascular endothelium (both tumor and normal), as it exists in vivo.

Range Charts for Agreement in Measurement Comparison Studies, With Application to Replicate Mass Spectrometry Experiments.

It is important to investigate the reproducibility of raw mass spectrometry (MS) features of abundance, such as spectral count, peptide number and ion intensity values, when conducting replicate mass spectrometry measurements. Reproducibility can be inferred from these replicate data either formally with analyses of variance techniques or informally with graphical procedures, particularly, Bland-Altman plots on paired runs. In this note, we suggest range plots to provide a suitable generalization of Bland-Altman plots to experiments with more than two replicate runs. We describe range charts and their interpretation, and illustrate their use with data from a recent proteomic study relating to label-free analysis.