Burosumab Improves Patient-Reported Outcomes in Adults With Tumor-Induced Osteomalacia: Mixed-Methods Analysis.

Tumor-induced osteomalacia (TIO) is an ultra-rare disease caused by tumors that secrete fibroblast growth factor 23, leading to chronic hypophosphatemia, poor skeletal health, and impaired physical function. In a phase 2 trial (UX023T-CL201; NCT02304367; n = 14), 48 weeks of burosumab treatment restored phosphate homeostasis, with improvements in skeletal health, functional mobility, and patient-reported pain, fatigue, and health-related quality of life (HRQL) (SF-36 v2). Here, we report an exploratory mixed-methods analysis of change from baseline after 144 weeks of burosumab treatment alongside qualitative data from exit interviews with 8 of 14 trial participants to evaluate meaningful treatment effects from a patient perspective. The interview subset (n = 8) reported pain and fatigue and compromised HRQL at baseline. In the interviews, participants reported that compromised HRQL and pain were the most important aspects of the disease to treat; both were considered more bothersome than fatigue and compromised physical function and activities of daily living. Improvements in pain and fatigue after treatment were reported, some of which achieved statistically and/or clinically meaningful thresholds. Furthermore, improvements in SF-36 v2 scores were most pronounced in the Physical Component Score and its Physical Function and Bodily Pain domains. Overall, the interview subset provided descriptions of symptomatic improvement and its clinical meaningfulness, including physical function, participation in activities of daily living, and mental well-being. Thus, this exploratory mixed-methods analysis provides deeper understanding of patients' perception of clinical meaningfulness beyond that articulated in validated patient-reported outcome instruments. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

The efficacy and safety of burosumab in two patients with cutaneous skeletal hypophosphatemia syndrome.

Cutaneous skeletal hypophosphatemia syndrome (CSHS) is an ultra-rare mosaic disorder manifesting as skeletal dysplasia and FGF23-mediated hypophosphatemia, with some experiencing extra-osseous/extra-cutaneous manifestations, including both benign and malignant neoplasms. Like other disorders of FGF23-mediated hypophosphatemia including X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO), patients with CSHS have low serum phosphorus and active 1,25-dihydroxyvitamin D levels. Current treatment options for patients with CSHS include multiple daily doses of oral phosphorus and one or more daily doses of active vitamin D analog to correct the deficits. Recently, the fully human monoclonal antibody against FGF23 burosumab received US approval for the treatment of XLH and TIO, two rare diseases characterized by FGF23-mediated hypophosphatemia leading to rickets and osteomalacia. Given the similarities between the pathobiologies of these disorders and CSHS, we investigated the impact of burosumab on two patients, one pediatric and one adult, with CSHS who participated in separate, but similarly designed trials. In both the pediatric and adult patients, burosumab therapy was well-tolerated and contributed to clinically meaningful improvements in disease outcomes including normalization of phosphorus metabolism and markers of bone health, and improvements in skeletal abnormalities, fractures, and physical function. Reported adverse events were minimal, with only mild injection site reactions attributed to burosumab therapy. Together, these findings suggest that burosumab therapy is a promising therapeutic option for patients with CSHS.

Burosumab for the Treatment of Tumor-Induced Osteomalacia.

Tumor-induced osteomalacia (TIO) is caused by phosphaturic mesenchymal tumors producing fibroblast growth factor 23 (FGF23) and is characterized by impaired phosphate metabolism, skeletal health, and quality of life. UX023T-CL201 is an ongoing, open-label, phase 2 study investigating the safety and efficacy of burosumab, a fully human monoclonal antibody that inhibits FGF23, in adults with TIO or cutaneous skeletal hypophosphatemia syndrome (CSHS). Key endpoints were changes in serum phosphorus and osteomalacia assessed by transiliac bone biopsies at week 48. This report focuses on 14 patients with TIO, excluding two diagnosed with X-linked hypophosphatemia post-enrollment and one with CSHS. Serum phosphorus increased from baseline (0.52 mmol/L) and was maintained after dose titration from week 22 (0.91 mmol/L) to week 144 (0.82 mmol/L, p < 0.0001). Most measures of osteomalacia were improved at week 48: osteoid volume/bone, osteoid thickness, and mineralization lag time decreased; osteoid surface/bone surface showed no change. Of 249 fractures/pseudofractures detected across 14 patients at baseline, 33% were fully healed and 13% were partially healed at week 144. Patients reported a reduction in pain and fatigue and an increase in physical health. Two patients discontinued: one to treat an adverse event (AE) of neoplasm progression and one failed to meet dosing criteria (receiving minimal burosumab). Sixteen serious AEs occurred in seven patients, and there was one death; all serious AEs were considered unrelated to treatment. Nine patients had 16 treatment-related AEs; all were mild to moderate in severity. In adults with TIO, burosumab exhibited an acceptable safety profile and was associated with improvements in phosphate metabolism and osteomalacia. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research..

Bacteriuria and asymptomatic infection in chronic patients with indwelling urinary catheter: The incidence of ESBL bacteria.

Urinary tract infections due to the presence of a urinary catheter represent a real problem for patients who have to carry such an invasive device for a long time.Our aim was to identify the susceptibility of extended spectrum beta lactamases (ESBL) versus non-ESBL bacteria to antibiotics in urinary tract infections in patients who are chronic carriers of urinary catheters.The retrospective study included a period of 5 years, a total of 405 patients who are chronic carriers of urinary catheters, admitted to rehabilitation and palliative care units.Escherichia coli (E coli) was isolated in 41.2% of patients, Klebsiella pneumoniae (K pneumoniae) in 24.7%, and Proteus mirabilis (P mirabilis) in 15.3%. E coli microbial resistance rates ranged from a minimum of 7.5% (nitrofurantoin) to a maximum of 77.1% (ampicillin). In the case of K pneumoniae, microbial resistance ranged from 34.2% (netilmicin) to 73.2% (ceftriaxone). Resistance rates of P mirabilis ranged from 11.1% (cefepim) to 89.5% (ampicillin). Positivity of ESBL bacteria was identified in 47.4% of patients. Resistance rates of ESBL-positive E coli ranged from 50.0% (ceftriaxone) to 88.1% (cefepime), and ESBL-negative E coli rates ranged from 3.4% (cefepime) to 64.4% (amikacin). Resistance rates of ESBL-positive K pneumoniae ranged between 39.1% (netilmicin) and 85.1% (ceftriaxone), and ESBL-negative K pneumoniae between 7.1% (cefepime) and 53.3% (amikacin). In cases of ESBL-positive P mirabilis, rates ranged from 13.3% (cefepime) to 90.3% (ceftriaxone), whereas in cases of ESBL-negative P mirabilis, rates ranged between 8.3% (cefepime) and 80.0% (trimetroprim).Bacteriuria and asymptomatic catheter infection in chronic carriers is an important public health concern due to the frequent presence of multidrug-resistant bacteria. Our study highlights the need to develop control programs of catheter infections to minimize the risk of infections associated with these medical devices, and also the need for treatment of the infection rather than catheter colonization or contamination.

A phase 1 study to evaluate the safety and LDL cholesterol-lowering effects of RG7652, a fully human monoclonal antibody against proprotein convertase subtilisin/kexin type 9.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9) downregulates low-density lipoprotein (LDL) receptors, thereby leading to a rise in circulating LDL cholesterol (LDL-C). RG7652 is a fully human monoclonal antibody against PCSK9. This placebo-controlled, phase 1 ascending-dose study in healthy subjects evaluated the safety of RG7652 and its efficacy as a potential LDL-C-lowering drug. HYPOTHESIS: Anti-PCSK9 antibody therapy safely and effectively reduces LDL-C. METHODS: Subjects (N = 80) were randomized into 10 cohorts. Six sequential single-dose cohorts received 10, 40, 150, 300, 600, or 800 mg of RG7652 via subcutaneous injection. Four multiple-dose cohorts received 40 or 150 mg of RG7652 once weekly for 4 weeks, either with or without statin therapy (atorvastatin). RESULTS: Adverse events (AEs) were generally mild; the most common AEs were temporary injection-site reactions. No serious AEs, severe AEs, AEs leading to study-drug discontinuation, or dose-limiting toxicities were reported. RG7652 monotherapy reduced mean LDL-C levels by up to 64% and as much as 100 mg/dL at week 2; the effect magnitude and duration increased with dose (≥57 days following a single RG7652 dose ≥300 mg). Exploratory analyses showed reduced oxidized LDL, lipoprotein(a), and lipoprotein-associated phospholipase A2 with RG7652. Antidrug antibody against RG7652 tested positive in 2 of 60 (3.3%) RG7652-treated and in 4 of 20 (20.0%) placebo-treated subjects. Simultaneous atorvastatin administration did not appear to impact the pharmacokinetic profile or lipid-lowering effects of RG7652. CONCLUSIONS: Overall, RG7652 elicited substantial and sustained dose-related LDL-C reductions with an acceptable safety profile and minimal immunogenicity.

Association Between Response to Etrolizumab and Expression of Integrin αE and Granzyme A in Colon Biopsies of Patients With Ulcerative Colitis.

BACKGROUND & AIMS: Etrolizumab is a humanized monoclonal antibody against the ß7 integrin subunit that has shown efficacy vs placebo in patients with moderate to severely active ulcerative colitis (UC). Patients with colon tissues that expressed high levels of the integrin αE gene (ITGAE) appeared to have the best response. We compared differences in colonic expression of ITGAE and other genes between patients who achieved clinical remission with etrolizumab vs those who did. METHODS: We performed a retrospective analysis of data collected from 110 patients with UC who participated in a phase 2 placebo-controlled trial of etrolizumab, as well as from 21 patients with UC or without inflammatory bowel disease (controls) enrolled in an observational study at a separate site. Colon biopsies were collected from patients in both studies and analyzed by immunohistochemistry and gene expression profiling. Mononuclear cells were isolated and analyzed by flow cytometry. We identified biomarkers associated with response to etrolizumab. In the placebo-controlled trial, clinical remission was defined as total Mayo Clinic Score ≤2, with no individual subscore >1, and mucosal healing was defined as endoscopic score ≤1. RESULTS: Colon tissues collected at baseline from patients who had a clinical response to etrolizumab expressed higher levels of T-cell-associated genes than patients who did not respond (P < .05). Colonic CD4(+) integrin αE(+) cells from patients with UC expressed higher levels of granzyme A messenger RNA (GZMA mRNA) than CD4(+) αE(-) cells (P < .0001); granzyme A and integrin αE protein were detected in the same cells. Of patients receiving 100 mg etrolizumab, a higher proportion of those with high levels of GZMA mRNA (41%) or ITGAE mRNA (38%) than those with low levels of GZMA (6%) or ITGAE mRNA (13%) achieved clinical remission (P < .05) and mucosal healing (41% GZMA(high) vs 19% GZMA(low) and 44% ITGAE(high) vs 19% ITGAE(low)). Compared with ITGAE(low) and GZMA(low) patients, patients with ITGAE(high) and GZMA(high) had higher baseline numbers of epithelial crypt-associated integrin αE(+) cells (P < .01 for both), but a smaller number of crypt-associated integrin αE(+) cells after etrolizumab treatment (P < .05 for both). After 10 weeks of etrolizumab treatment, expression of genes associated with T-cell activation and genes encoding inflammatory cytokines decreased by 40%-80% from baseline (P < .05) in patients with colon tissues expressing high levels of GZMA at baseline. CONCLUSIONS: Levels of GZMA and ITGAE mRNAs in colon tissues can identify patients with UC who are most likely to benefit from etrolizumab; expression levels decrease with etrolizumab administration in biomarker(high) patients. Larger, prospective studies of markers are needed to assess their clinical value.

Etrolizumab as induction therapy for ulcerative colitis: a randomised, controlled, phase 2 trial.

BACKGROUND: Etrolizumab is a humanised monoclonal antibody that selectively binds the ß7 subunit of the heterodimeric integrins α4ß7 and αEß7. We aimed to assess etrolizumab in patients with moderately-to-severely active ulcerative colitis. METHODS: In this double-blind, placebo-controlled, randomised, phase 2 study, patients with moderately-to-severely active ulcerative colitis who had not responded to conventional therapy were recruited from 40 referral centres in 11 countries. Eligible patients (aged 18-75 years; Mayo Clinic Score [MCS] of 5 of higher [or ≥6 in USA]; and disease extending 25 cm or more from anal verge) were randomised (1:1:1) to one of two dose levels of subcutaneous etrolizumab (100 mg at weeks 0, 4, and 8, with placebo at week 2; or 420 mg loading dose [LD] at week 0 followed by 300 mg at weeks 2, 4, and 8), or matching placebo. The primary endpoint was clinical remission at week 10, defined as MCS of 2 or less (with no individual subscore of >1), analysed in the modified intention-to-treat population (mITT; all randomly assigned patients who had received at least one dose of study drug, had at least one post-baseline disease-activity assessment, and had a centrally read screening endoscopic subscore of ≥2). This study is registered with ClinicalTrials.gov, number NCT01336465. FINDINGS: Between Sept 2, 2011, and July 11, 2012, 124 patients were randomly assigned, of whom five had a endoscopic subscore of 0 or 1 and were excluded from the mITT population, leaving 39 patients in the etrolizumab 100 mg group, 39 in the etrolizumab 300 mg plus LD group, and 41 in the placebo group for the primary analyses. No patients in the placebo group had clinical remission at week 10, compared with eight (21% [95% CI 7-36]) patients in the etrolizumab 100 mg group (p=0·0040) and four (10% [0·2-24]) patients in the 300 mg plus LD group (p=0·048). Adverse events occurred in 25 (61%) of 41 patients in the etrolizumab 100 mg group (five [12%] of which were regarded as serious), 19 (48%) of 40 patients in the etrolizumab 300 mg plus LD group (two [5%] serious), and 31 (72%) of 43 patients in the placebo group (five [12%] serious). INTERPRETATION: Etrolizumab was more likely to lead to clinical remission at week 10 than was placebo. Therefore, blockade of both α4ß7 and αEß7 might provide a unique therapeutic approach for the treatment of ulcerative colitis, and phase 3 studies have been planned. FUNDING: Genentech.

EMerging BiomARKers in Inflammatory Bowel Disease (EMBARK) study identifies fecal calprotectin, serum MMP9, and serum IL-22 as a novel combination of biomarkers for Crohn's disease activity: role of cross-sectional imaging.

OBJECTIVES: In Crohn's disease (CD), clinical symptoms correspond poorly to inflammatory disease activity. Biomarkers reflective of mucosal and bowel wall inflammation would be useful to monitor disease activity. The EMBARK study evaluated disease activity in patients with ulcerative colitis (UC) and CD, and used endoscopy with or without cross-sectional imaging for biomarker discovery. METHODS: UC (n=107) and CD (n=157) patients were characterized and underwent ileocolonoscopy (ICO). A subset of CD patients (n=66) also underwent computed tomography enterography (CTE). ICO and CTE were scored by a gastroenterologist and radiologist who incorporated findings of inflammation into a single score (ICO-CTE) for patients that underwent both procedures. Serum and fecal biomarkers were evaluated for association with the Mayo Clinic endoscopy score in UC patients and with ICO alone or ICO-CTE in CD patients. Individual biomarkers with a moderate degree of correlation (P≤0.3) were evaluated using multivariate analysis with model selection using a stepwise procedure. RESULTS: In UC, ordinal logistic regression using Mayo Clinic endoscopy subscore selected the combination of fecal calprotectin and serum matrix metalloproteinase 9 (MMP9; pseudo R(2)=0.353). In CD, we found that use of the ICO-CTE increased specificity of known biomarkers. Using ICO-CTE as the dependent variable for biomarker discovery, the selected biomarkers were the combination of fecal calprotectin, serum MMP9, and serum IL-22 (r=0.699). CONCLUSIONS: Incorporation of both ICO and CTE into a single measure increased biomarker performance in CD. Combinations of fecal calprotectin and serum MMP9 for UC, and combinations of fecal calprotectin, serum MMP9, and serum interleukin-22 in CD, demonstrated the strongest association with imaging/endoscopy-defined inflammation.

A randomised phase I study of etrolizumab (rhuMAb ß7) in moderate to severe ulcerative colitis.

OBJECTIVE: Etrolizumab (rhuMAb ß7, anti-ß7, PRO145223) is a humanised monoclonal antibody targeting the ß7 subunit of the heterodimeric integrins α4ß7 and αEß7, which are implicated in leucocyte migration and retention in ulcerative colitis (UC). This randomised phase I study evaluated the safety and pharmacology of etrolizumab in patients with moderate to severe UC. DESIGN: In the single ascending dose (SAD) stage, etrolizumab (0.3, 1.0, 3.0, 10 mg/kg intravenous, 3.0 mg/kg subcutaneous (SC) or placebo) was administered 4:1 (n=25) in each cohort. In the multiple dose (MD) stage, new patients received monthly etrolizumab (0.5 mg/kg SC (n=4), 1.5 mg/kg SC (n=5), 3.0 mg/kg SC (n=4), 4.0 mg/kg intravenous (n=5)) or placebo (n=5). The pharmacokinetics was studied and Mayo Clinic Score evaluated at baseline, day 29 (SAD), and days 43 and 71 (MD). RESULTS: In the SAD stage, there were no dose limiting toxicities, infusion or injection site reactions. Two impaired wound healing serious adverse events occurred in two patients receiving etrolizumab. In the MD stage, there were no dose limiting toxicities, and no infusion or injection site reactions. Headache was the most common adverse event, occurring more often in etrolizumab patients. Antietrolizumab antibodies were detected in two subjects. The duration of ß7 receptor full occupancy was dose related. A clinical response was observed in 12/18 patients, and clinical remission in 3/18 patients treated with etrolizumab in the MD stage, compared with 4/5 and 1/5 placebo patients, respectively. CONCLUSION: Etrolizumab is well tolerated in moderate to severe UC. Further investigation is warranted.

Safety, pharmacokinetics, and biologic activity of pateclizumab, a novel monoclonal antibody targeting lymphotoxin α: results of a phase I randomized, placebo-controlled trial.

INTRODUCTION: Pateclizumab (MLTA3698A) is a humanized mAb against lymphotoxin α (LTα), a transiently expressed cytokine on activated B and T cells (Th1, Th17), which are implicated in rheumatoid arthritis (RA) pathogenesis. This study was conducted to assess the safety, tolerability, < NOTE: For clarity and per AMA/S-W Style, please restore the use of Oxford/serial commas (ie: David likes vanilla, strawberry, and chocolate ice cream) throughout. and biologic activity of single and multiple doses of intravenous (IV) or subcutaneous (SC) pateclizumab in RA patients. METHODS: The single ascending dose (SAD) phase in patients with stable RA consisted of six cohorts (4:1 active:placebo at 0.3 mg/kg IV, 1.0 mg/kg IV, 1.0 mg/kg SC, 3.0 mg/kg IV, 3.0 mg/kg SC, and 5.0 mg/kg IV; n = 5/cohort). In the multiple ascending dose (MAD) phase, patients with prespecified RA disease activity received three doses of pateclizumab or placebo (4:1) every 2 weeks (1.0 mg/kg SC, n = 10; 3.0 mg/kg SC, n = 20; or 5.0 mg/kg IV, n = 5). Safety and tolerability were assessed throughout, and clinical activity was determined after three doses (Week 6). RESULTS: We observed no serious adverse events (AEs) or dose-limiting toxicities, and the majority of AEs were mild to moderate. The pharmacokinetic profiles were linear, and clearance was independent of dose. Reductions in levels of serum CXCL13 were observed, supporting the biologic activity of pateclizumab on the LTα pathway. Patients receiving pateclizumab in the 3.0 mg/kg MAD group (3.0 mg/kg SC) demonstrated ACR20, ACR50, and ACR70 response rates at week 6 of 75%, 56% and 25%, respectively, compared with 57%, 29%, and 0% in the placebo group. The median Disease Activity Score in 28 joints, C-reactive protein, reduction was 28% for pateclizumab, versus 8.4% for placebo. CONCLUSIONS: Pateclizumabwas generally well-tolerated in RA patients. Preliminary evidence of clinical activity was observed in active RA patients at the dose level targeted for clinical effect.

A SPECTRAL GRAPH APPROACH TO DISCOVERING GENETIC ANCESTRY.

Mapping human genetic variation is fundamentally interesting in fields such as anthropology and forensic inference. At the same time, patterns of genetic diversity confound efforts to determine the genetic basis of complex disease. Due to technological advances, it is now possible to measure hundreds of thousands of genetic variants per individual across the genome. Principal component analysis (PCA) is routinely used to summarize the genetic similarity between subjects. The eigenvectors are interpreted as dimensions of ancestry. We build on this idea using a spectral graph approach. In the process we draw on connections between multidimensional scaling and spectral kernel methods. Our approach, based on a spectral embedding derived from the normalized Laplacian of a graph, can produce more meaningful delineation of ancestry than by using PCA. The method is stable to outliers and can more easily incorporate different similarity measures of genetic data than PCA. We illustrate a new algorithm for genetic clustering and association analysis on a large, genetically heterogeneous sample.

Discovering genetic ancestry using spectral graph theory.

As one approach to uncovering the genetic underpinnings of complex disease, individuals are measured at a large number of genetic variants (usually SNPs) across the genome and these SNP genotypes are assessed for association with disease status. We propose a new statistical method called Spectral-GEM for the analysis of genome-wide association studies; the goal of Spectral-GEM is to quantify the ancestry of the sample from such genotypic data. Ignoring structure due to differential ancestry can lead to an excess of spurious findings and reduce power. Ancestry is commonly estimated using the eigenvectors derived from principal component analysis (PCA). To develop an alternative to PCA we draw on connections between multidimensional scaling and spectral graph theory. Our approach, based on a spectral embedding derived from the normalized Laplacian of a graph, can produce more meaningful delineation of ancestry than by using PCA. Often the results from Spectral-GEM are straightforward to interpret and therefore useful in association analysis. We illustrate the new algorithm with an analysis of the POPRES data [Nelson et al., 2008].

Searching for disease susceptibility variants in structured populations.

Data for genome-wide association studies are being collected for a myriad of phenotypes. Many of these studies do not include control samples selected to reflect ancestry similar to the case samples. At the same time "control databases" are becoming available to be utilized as a common resource. These data are often genotyped using a large-scale SNP array. Human populations exhibit complex structure that can lead to spurious associations if not properly handled. How to couple case and control databases effectively is a pressing question. We review available methods for modeling genetic ancestry based on the information gleaned from the SNP array. Methods for selecting control samples with genetic ancestry similar to the case samples are described.

On the use of general control samples for genome-wide association studies: genetic matching highlights causal variants.

Resources being amassed for genome-wide association (GWA) studies include "control databases" genotyped with a large-scale SNP array. How to use these databases effectively is an open question. We develop a method to match, by genetic ancestry, controls to affected individuals (cases). The impact of this method, especially for heterogeneous human populations, is to reduce the false-positive rate, inflate other spuriously small p values, and have little impact on the p values associated with true positive loci. Thus, it highlights true positives by downplaying false positives. We perform a GWA by matching Americans with type 1 diabetes (T1D) to controls from Germany. Despite the complex study design, these analyses identify numerous loci known to confer risk for T1D.

Pleiotropy and principal components of heritability combine to increase power for association analysis.

When many correlated traits are measured the potential exists to discover the coordinated control of these traits via genotyped polymorphisms. A common statistical approach to this problem involves assessing the relationship between each phenotype and each single nucleotide polymorphism (SNP) individually (PHN); and taking a Bonferroni correction for the effective number of independent tests conducted. Alternatively, one can apply a dimension reduction technique, such as estimation of principal components, and test for an association with the principal components of the phenotypes (PCP) rather than the individual phenotypes. Building on the work of Lange and colleagues we develop an alternative method based on the principal component of heritability (PCH). For each SNP the PCH approach reduces the phenotypes to a single trait that has a higher heritability than any other linear combination of the phenotypes. As a result, the association between a SNP and derived trait is often easier to detect than an association with any of the individual phenotypes or the PCP. When applied to unrelated subjects, PCH has a drawback. For each SNP it is necessary to estimate the vector of loadings that maximize the heritability over all phenotypes. We develop a method of iterated sample splitting that uses one portion of the data for training and the remainder for testing. This cross-validation approach maintains the type I error control and yet utilizes the data efficiently, resulting in a powerful test for association.