Immunoassay methods used in clinical studies for the detection of anti-drug antibodies to adalimumab and infliximab

We examined the assay formats used to detect anti-drug antibodies (ADA) in clinical studies of the anti-tumour necrosis factor (TNF) monoclonal antibodies adalimumab and infliximab in chronic inflammatory disease and their potential impact on pharmacokinetic and clinical outcomes. Using findings of a recent systematic literature review of the immunogenicity of 11 biological/biosimilar agents, we conducted an ancillary qualitative review of a subset of randomized controlled trials and observational studies of the monoclonal antibodies against anti-TNF factor adalimumab and infliximab. Among studies of adalimumab and infliximab, the immunoassay method used to detect antibodies was reported in 91 of 111 (82%) and 154 of 206 (75%) adalimumab and infliximab studies, respectively. In most adalimumab and infliximab studies, an enzyme-linked immunosorbent assay or radioimmunoassay was used [85 of 91 (93%) and 134 of 154 (87%), respectively]. ADA incidence varied widely among assays and inflammatory diseases (adalimumab, 0-87%; infliximab, 0-79%). Pharmacokinetic and clinical outcomes were only reported for ADA-positive patients in 38 of 91 (42%) and 61 of 154 (40%) adalimumab and infliximab studies, respectively. Regardless of assay format or biological used, ADA formation was associated with lower serum concentrations, reduced efficacy and elevated rates of infusion-related reactions. Consistent with previous recommendations to improve interpretation of immunogenicity data for biologicals, greater consistency in reporting of assay methods and clinical consequences of ADA formation may prove useful. Additional standardization in immunogenicity testing and reporting, application of modern, robust assays that satisfy current regulatory expectations and implementation of international standards for marketed products may help to improve our understanding of the impact of immunogenicity to biologics.

Assessing the Impact of Tissue Target Concentration Data on Uncertainty in In Vivo Target Coverage Predictions

Understanding pharmacological target coverage is fundamental in drug discovery and development as it helps establish a sequence of research activities, from laboratory objectives to clinical doses. To this end, we evaluated the impact of tissue target concentration data on the level of confidence in tissue coverage predictions using a site of action (SoA) model for antibodies. By fitting the model to increasing amounts of synthetic tissue data and comparing the uncertainty in SoA coverage predictions, we confirmed that, in general, uncertainty decreases with longitudinal tissue data. Furthermore, a global sensitivity analysis showed that coverage is sensitive to experimentally identifiable parameters, such as baseline target concentration in plasma and target turnover half‐life and fixing them reduces uncertainty in coverage predictions. Overall, our computational analysis indicates that measurement of baseline tissue target concentration reduces the uncertainty in coverage predictions and identifies target‐related parameters that greatly impact the confidence in coverage predictions.

Translational Pharmacokinetic/Pharmacodynamic Analysis of MYO-029 Antibody for Muscular Dystrophy

Suppression of the myostatin (GDF‐8) pathway has emerged as an important therapeutic paradigm for muscle‐wasting disorders. In this study, we conducted a translational pharmacokinetic/pharmacodynamic (PK/PD) analysis of MYO‐029, an anti‐myostatin monoclonal antibody, using PK data in mice, rats, monkeys, humans, mouse tissue distribution data with ¹²⁵I‐labeled MYO‐029, muscle weight increase in SCID mice, and muscle circumference changes in monkeys. This analysis revealed significant in vivo potency shift between mice and monkeys (72 nM vs. 1.3 μM for 50% effect on quadriceps). Estimated central clearance of MYO‐029 (0.38 mL/h/kg) in humans was greater than twofold higher than typical IgG mAbs. Peak and trough steady‐state exposures of MYO‐029 in patients at biweekly intravenous doses of 10 mg/kg MYO‐029 are predicted to achieve only 50% and 10% of the maximum effect seen in monkeys, respectively. These retrospective analyses results suggest that the MYO‐029 exposures in this trial had a low probability of producing robust efficacy.

Making Every Subject Count: A Case Study of Drug Development Path for Medication in a Pediatric Rare Disease

Approximately 50% of rare diseases are evident in children. Fatal disease prognosis and lack of treatments causes 30% of affected children to not live past their fifth birthday. This clear sense of urgency demands innovation and acceleration in drug development. A case study is discussed highlighting the need for data-rich phase I study design, extensive use of modeling and simulation, use of diverse data sources, and input from collaborators to respond to this urgent call.

Hormone responsiveness of cultured Sertoli cells obtained from adult rats after their rapid isolation under less harsh conditions

During adulthood, testicular Sertoli cells (Sc) coordinate all stages of germ cell (Gc) development involved in sperm production. However, our understanding about the functions of adult Sc is limited because of the difficulties involved in the process of isolating these cells from the adult testis, mainly because of the presence of large number of advanced Gc which interfere with Sc isolation at this age. Most of our knowledge about Sc function are derived from studies which used pre-pubertal rat Sc (18 ± 2-day old) as it is easy to isolate and culture Sc at this age. To this end, we established a less time consuming and less harsh procedure of isolating Sc from adult (60 days of age) rat testis for facilitating research on Sc-mediated regulation of spermatogenesis during adulthood. The cells were isolated using collagenase digestion at higher temperature, reducing the exposure time of cells to the enzyme. Step-wise digestion with intermittent removal of small clusters of tissue helped in increasing the yield of Sc. Isolated Sc were cultured and treated with FSH and testosterone (T) to evaluate their hormone responsiveness in terms of lactate, E2 , cAMP production. Adult Sc were found to be active and produced high amounts of lactate in a FSH-independent manner. FSH-mediated augmentation of cAMP and E2 production by adult Sc was less as compared with that by pre-pubertal Sc obtained from 18-day-old rats. Androgen-binding ability of adult Sc was significantly higher than pre-pubertal Sc. Although T treatment remarkably augmented expression of Claudin 11, it failed to augment lactate production by adult Sc. This efficient and rapid procedure for isolation and culture of functionally viable adult rat Sertoli cells may pave the way for determining their role in regulation and maintenance of spermatogenesis.

Query-time Entity Resolution

Entity resolution is the problem of reconciling database references corresponding to the same real-world entities. Given the abundance of publicly available databases that have unresolved entities, we motivate the problem of query-time entity resolution quick and accurate resolution for answering queries over such `unclean' databases at query-time. Since collective entity resolution approaches --- where related references are resolved jointly --- have been shown to be more accurate than independent attribute-based resolution for off-line entity resolution, we focus on developing new algorithms for collective resolution for answering entity resolution queries at query-time. For this purpose, we first formally show that, for collective resolution, precision and recall for individual entities follow a geometric progression as neighbors at increasing distances are considered. Unfolding this progression leads naturally to a two stage `expand and resolve' query processing strategy. In this strategy, we first extract the related records for a query using two novel expansion operators, and then resolve the extracted records collectively. We then show how the same strategy can be adapted for query-time entity resolution by identifying and resolving only those database references that are the most helpful for processing the query. We validate our approach on two large real-world publication databases where we show the usefulness of collective resolution and at the same time demonstrate the need for adaptive strategies for query processing. We then show how the same queries can be answered in real-time using our adaptive approach while preserving the gains of collective resolution. In addition to experiments on real datasets, we use synthetically generated data to empirically demonstrate the validity of the performance trends predicted by our analysis of collective entity resolution over a wide range of structural characteristics in the data.

Carbohydrate analysis of bradyrhizobial (NC92) lipopolysaccharides by high performance-anion exchange chromatography with pulsed amperometric detection

Composition analysis of monosaccharides of Sepharose 4B purified NC 92 LPS and the polysaccharides fractions from Sephadex G-50 chromatography was performed by high performance anion exchange chromatography using pulsed amperometric detection. Rhamnose, mannose, galactose and glucose are present in a substantial amount in the purified LPS (Pk I). High molecular weight purified polysaccharides (PS I) obtained after sephadex gel filtration of the purified LPS (Pk I) acid hydrolysate showed an increase in glucose:galactose ratio. This indicates the presence of the peanut root lectin (PRA II) specific sugar in higher proportion on the O-antigen part of the LPS molecule, which may aid in the critical recognition reaction.

Prospective determination of distal colon findings in average-risk patients with proximal colon cancer

BACKGROUND

Recent guidelines indicate that colonoscopy and sigmoidoscopy are both acceptable options for screening average-risk patients for colorectal cancer. Retrospective studies have found that a majority of patients with cancer proximal to the splenic flexure have a normal screening flexible sigmoidoscopy.

METHODS

This was a multicenter, prospective description of colonoscopic findings and family history in consecutive patients with proximal colon cancer.

RESULTS

Among 116 prospectively identified average-risk patients with cancer proximal to the splenic flexure, 40 (34.5%) had neoplasia distal to the splenic flexure. The prevalence of patients with adenomas greater than or equal to 1 cm, with only one tubular adenoma less than 1 cm, and with only hyperplastic polyps were 16.4%, 8.6%, and 6.9%, respectively.

CONCLUSIONS

Most average-risk patients with cancer proximal to the splenic flexure will have a normal screening flexible sigmoidoscopy. These patients have an unexpectedly high prevalence of large distal adenomas, but the prevalence of both single small tubular adenomas and hyperplastic polyps alone is similar to that expected during screening of the general population. Clinicians and payers should continue to seek methods to improve the cost-effectiveness and availability of screening colonoscopy in average-risk persons.

Technology and staffing in Japanese university hospitals. Government versus private

We examined staffing levels, acquisition of medical technologies, and utilization of those technologies in private and government teaching hospitals in Japan. Adjusting for size and case mix, we found that government hospitals acquire more technology, use that technology less, and employ a more highly skilled staff than do private hospitals.

Effects of radiopharmaceuticals on radioenzymatic assays of aminoglycoside antibiotics: interference by gallium-67 and its elimination

Radionuclides currently used in clinical medicine were evaluated for their possible interference with radioenzymatic assays of aminoglycoside antibiotics. Of the radiopharmaceuticals tested, only (67)Ga citrate interfered with the radioenzymatic assay of gentamicin. Radioenzymatic assay of serum samples obtained from patients receiving (67)Ga yielded gentamicin concentrations falsely elevated by more than 1 mug/ml for approximately 1 week after (67)Ga administration. A procedure was developed to eliminate (67)Ga interference with radioenzymatic assays of aminoglycoside antibiotics. After (67)Ga citrate was spotted onto phosphocellulose filter disks, the filters were immersed in 7.2 N HCl, and radioactivity was removed by successive extractions of the acid phase with diisopropyl ether. After three extractions, less than 0.1% of the original radioactivity remained. Similar extraction of disks containing (14)C-adenylylated gentamicin or tobramycin or (14)C-acetylated amikacin had no effect on (14)C radioactivity. The concentrations of aminoglycosides in serum standards supplemented with (67)Ga citrate were determined accurately by radioenzymatic assays followed by extraction with diisopropyl ether. Concentrations of gentamicin in six serum samples from patients injected with (67)Ga during gentamicin therapy, as determined by radioenzymatic assay and extraction, were within 9% of the results obtained by reassay of the same samples after the decay of (67)Ga.