A competitive ligand-binding assay for the detection of neutralizing antibodies against dostarlimab (TSR-042)

Dostarlimab is a humanized anti–PD-1 monoclonal antibody. Dostarlimab (JEMPERLI; TSR-042) was recently approved in the USA and in the EU. The presence of neutralizing antibodies (NAbs) is a cause for concern because they block the therapeutic function of the antibody and reduce drug efficacy. Therefore, programs developing therapeutic biologics need to develop and validate assays that adequately assess the presence of NAbs in the serum of patients treated with biologic therapies. Presented here is the development and validation of a competitive ligand-binding assay that specifically detects anti-dostarlimab NAbs in human serum. Precision, sensitivity, hook effect, selectivity, assay robustness, stabilities, and system suitability were evaluated. In addition, drug tolerance of the assay with the implementation of a drug removal process was investigated. The cut point factor for the detection of NAbs in human serum at a 1% false-positive rate was determined. The assay’s precision, sensitivity, hook effect, selectivity, robustness, and drug interference were tested and found to be acceptable. With system suitability and stability established, this assay has been used to evaluate NAbs to guide the development of dostarlimab.Trial registration: Clinicaltrials.gov, NCT02715284. Registered 9 March 2016

No Diagnostic Utility of Zero Heparin Control Buffer in Serotonin Release Assay: Findings from a Validation Study

Background: Heparin induced thrombocytopenia (HIT) is a rare immune mediated complication that is triggered in a subset of patients temporal to therapeutic heparin exposure. Laboratory testing is based on screening for the presence of serum anti-PF4 antibodies using sensitive solid-phase immunoassays. If antibodies are detected, functional testing to demonstrate the platelet activating properties and heparin dependence of these immune complexes is then performed. Previous studies have reported possible clinical utility in identifying non heparin dependent platelet activating antibodies using a buffer control with zero heparin in the serotonin release functional assay (SRA). These reports suggested a correlation between reactivity in the zero heparin buffer control and pathogenicity of HIT antibodies which may define a subtype of HIT, referred to as autoimmune HIT. We aimed to investigate the utility of zero heparin buffer control as a part of an inhouse validation study of a mass spectrometry-coupled SRA (Mayo-SRA). Methods: Three hundred archived serum samples were tested using anti-PF4 IgG antibody enzyme-linked immunosorbent assay (ELISA; Immucor Diagnostics, GA, USA). SRA was preformed on all samples using Mayo-SRA and reference 14C SRA methods. Zero heparin control buffer was included in the Mayo-SRA assay. Serotonin release >20% in the low dose heparin (0.1U/mL, LDH) and ELISA optical density (OD) >0.4 were considered positive. Drug interference studies were performed by spiking known SRA-positive samples with increasing concentrations of unfractionated heparin (UFH), low molecular weight heparin (LMWH) or fondaparinux in the LDH and zero heparin SRA. The clinical 4T score was calculated retrospectively calculated for all patients. Results: Of the 300 tested samples, 57 were anti-PF4 ELISA positive. 33 of the 57 samples were positive using the reference 14C SRA method. Whereas 43 samples were positive by Mayo-SRA assay. Three additional samples were positive by Mayo-SRA, but negative by both screening anti-PF4 ELISA and the reference SRA method (Fig- 1A). Lastly, 13 samples were anti-PF4 ELISA positive, but SRA negative by both methods in comparison. Interestingly, 44 of 46 (95%) samples interpreted positive by LDH were also interpreted positive (serotonin release >20%) under zero heparin conditions. These included the 3 samples that were positive by Mayo-SRA but negative by both screening anti-PF4 ELISA and the reference SRA. The overall % serotonin release using zero heparin control was significantly lower (P= 0.003, paired Student T-test) compared to LDH (Fig-1B). In addition, zero heparin followed a similar pattern as LDH, with highest levels at ELISA OD units >2 (Fig-1C). Strikingly, drug interference studies showed artifactual serotonin release in the zero heparin reaction, which was not detected in the absence of spiked drugs. For UFH, serotonin release in zero heparin control occurred at very low spiked concentrations, ≥0.063 U/mL. LMWH and fondaparinux spiking experiments also displayed similar zero heparin serotonin release patterns (Fig-1D). Of note, none of these interferences were detected in UFH spiked SRA-negative samples (data not shown). Conclusion: Contrary to prior results suggesting that less than 50% of LDH SRA positive samples are also positive in the zero heparin SRA, our results show high zero heparin SRA positivity rate of >95%. Zero heparin SRA showed a pattern with highest levels at ELISA OD units >2 suggesting that reactivity in this condition is a function of antibody strength rather than a qualitative difference (i.e. "autoimmune" HIT antibodies vs "non-autoimmune" HIT antibodies). In addition, contamination of patient sera with small amounts of remnant heparin can significantly impact platelet activation in the zero heparin SRA test. Thus, zero heparin SRA positive results may be artifactual and represent residual heparin contained in the patient sample. Figure legend: Fig-1A. Scatter plots of SRA positive samples grouped by 4T scores. Red dots are Mayo-SRA only positive samples. Fig-1B and Fig-1C. Scatter plots of % serotonin release of Mayo-SRA positive samples at LDH (circles) vs. zero heparin buffers (squares), and grouped by ELISA OD values, respectively. Fig-1D. % Serotonin release of known SRA-positive samples spiked with increasing concentrations of UFH, LMWH, or fondaparinux at LDH (white) or zero heparin buffers (red). Figure 1 Figure 1. Disclosures Pruthi: CSL Behring: Honoraria; Genentech: Honoraria; Bayer Healthcare AG: Honoraria; HEMA Biologics: Honoraria; Instrumentation Laboratory: Honoraria; Merck: Honoraria. Padmanabhan: Veralox Therapeutics: Membership on an entity's Board of Directors or advisory committees.

P12.08 Efficacy of trazodone slow release in insomnia associated with high-dose steroid therapy in neuro-oncological patients

BACKGROUND Insomnia linked to therapeutical intake of intravenous (IV) megadoses of steroid (Mgds, 8–16 mg) is a common side effect in neuro-oncology patients. Hypno-inducing drugs (IP) and Benzodiazepines (BDZ) can provoke drug interference and daytime sedation. Trazodone (Trz) is an atypical antidepressant with poor liver metabolism; it has moderate histamine-1 (H1) receptor antagonism and possesses some anxiolytic and hypnotic properties. We tested the use of the Trz retard (RP) formulation as a hypnotic drug in patients undergoing a therapeutic regimen with IV Mgds. To evaluate anxiety and side effects. MATERIAL AND METHODS 10 patients (6 females and 4 males) admitted to the Neuro-oncology Department of the Neurological Institute “Carlo Besta” treated with Mgds IV. The average age was 55 years and the mean HAM-A score was 25. Instruments included the Hamilton Anxiety Scale (HAM-A), the Clinical Global Impression (CGI), and the Pittsburgh Sleep Quality Index (PSQI). Trz RP was administered at a dosage of 25-50-75 mg/day in the evening. RESULTS All 10 patients reported improved hypnotic profiles within the third day of Trz RP administration. Four patients improved on the first day. Reduction of the HAM-A score was found on the third day. No adverse events (epilepsy, daytime sedation, incontinence) were observed in 3 weeks. CONCLUSIONS Trz RP proved to have a swift beneficial effect on sleep and anxiety without side effects in the short term. Trz may be preferred to IP and BDZ in patients receiving IV Mgds, considering the lack of daytime sedation and the reduced pharmacological inference. Larger samples will enable future research to better describe the characteristics and the indication of Trz.

Current Potential of Pantoprazole in Treatment and Prevention of Gastrointestinal Diseases

Aim. An outline of the current potential of pantoprazole in treatment and prevention of upper gastrointestinal diseases.Key points. Pantoprazole is widely applied in gastroesophageal reflux, peptic ulcer disease, Zollinger—Ellison syndrome and for Helicobacter pylori eradication. It minimally inhibits the CYP2C19 isoenzyme involved in the metabolism of many drugs. Pharmacokinetics of pantoprazole conditions a weaker drug interaction compared to other proton pump inhibitors (PPIs), which enables its use for gastrointestinal bleeding prevention in patients receiving dual antiplatelet therapy. The new coronaviral pandemic of COVID-19 urges the selection of PPIs that minimise the drug interference, such as pantoprazole, in therapy and prevention of acid-related upper gastrointestinal diseases. Pantoprazole has a good tolerance and low side effect rate.Conclusion. Pantoprazole is considered among optimal PPIs for efficacy, safety and adherence on the basis of clinical trials for treatment and prevention of gastrointestinal diseases, systematic reviews and meta-analyses.

Development of an Meso Scale Discovery ligand-binding assay for measurement of free (drug-unbound) target in nonhuman primate serum

Aim: To quantify the free form of a protein as a target-engagement biomarker in nonhuman primate serum, a Meso Scale Discovery ligand-binding assay was developed and qualified. Results: The initial assay produced an unexpected artifact when used to measure the free target in study samples dosed with drug. By using incurred study samples dosed with high drug levels to test assay performance, we developed an alternative assay that does not suffer from drug interference. Conclusion: Our work demonstrated that an assay designed to measure free target may not necessarily deliver reliable quantitation. In our case, incurred study samples dosed with drug proved to be useful in developing an alternative free assay that does not suffer from drug interference.

Population-scale patient safety data reveal inequalities in adverse events before and during COVID-19 pandemic

Adverse patient safety events were associated with 110 thousand deaths in the U.S. alone in 2019. The COVID-19 pandemic has further challenged the ability of healthcare systems to ensure medication safety, and its effects on patient safety remain unknown. Here, we investigate negative outcomes associated with medication use before and during the pandemic. Using a dataset of 10,443,476 reports involving 3,624 drugs and 19,193 adverse events, we develop an algorithmic approach to analyze the pandemic's impact on incidence of drug safety events by evaluating disproportional reporting relative to the pre-pandemic time, quantifying unexpected trends in clinical outcomes, and adjusting for drug interference. Among 64 adverse events identified by our analyses, we find 54 have increased incidence rates during the pandemic, even though reporting of adverse events has decreased by 4.4% overall. We find clinically relevant differences in drug safety outcomes between demographic groups. Comparing to male patients, women report 47.0% more distinct adverse events whose occurrence significantly increased during the pandemic relative to pre-pandemic levels. Out of 53 adverse events with the pre-pandemic gender gap, 33 have increased gap during the pandemic more than would have been expected had the pandemic not occurred. While musculoskeletal and metabolic side effects are disproportionately enriched in women during the pandemic, immune-related adverse events are enriched only in men. We also find the number of adverse events with a higher reporting ratio during the pandemic in adults is higher (16.8%) than in older patients (adjusted for population size). Our findings have implications for safe medication use and public health policy and highlight the role of variation in adverse events for improving patient safety during a public health emergency.

Comparison of the ELISA and ECL Assay for Vedolizumab Anti-drug Antibodies: Assessing the Impact on Pharmacokinetics and Safety Outcomes of the Phase 3 GEMINI Trials

Vedolizumab immunogenicity has been assessed using an enzyme-linked immunosorbent assay (ELISA) with a ~ 0.5 μg/mL drug interference, which may underestimate on-drug immunogenicity. We aimed to compare immunogenicity results between ELISA and the new drug-tolerant electrochemiluminescence (ECL) assay (and the two versions of neutralizing assays, drug-sensitive versus drug-tolerant). The ECL assay drug tolerance is ~ 100 times higher than that of the ELISA (≥ 50 μg/mL vs. 0.5 μg/mL with a 500 ng/mL positive control), and assay sensitivity is < 5 ng/mL for both assays. Vedolizumab immunogenicity was assessed in 2000 GEMINI 1 and 2 patients originally tested by ELISA and retested by ECL assay. Anti-drug antibody (ADA) impact on infusion-related reactions and pharmacokinetics (PK) was examined using descriptive statistics and population PK analyses. By ECL assay, 6% (86/1427) of patients treated with vedolizumab as induction and maintenance therapy tested ADA-positive. Of these, 20 patients were persistently positive and 56 had neutralizing antibodies. By ELISA, 4% (56/1434) of these patients were ADA-positive, 9 were persistently positive, and 33 had neutralizing antibodies. Among 61 patients with infusion-related reactions, 6 (10%) were ADA-positive (2 persistently positive) by ECL assay. By ELISA, 3 (5%) patients were both ADA-positive and persistently positive. Most results (96%) were similar with both assays. In the updated population PK model, ADA-positive status was estimated to increase vedolizumab linear clearance by a factor of 1.10 (95% credible interval 1.03–1.17), which is consistent with previous reports. The impact of ADA on safety and PK modeling remained generally consistent using either ELISA or ECL assay. ClinicalTrials.gov: NCT00783718 and NCT00783692

Strategies to develop highly drug-tolerant cell-based neutralizing antibody assay: neutralizing antidrug antibodies extraction and drug depletion

Aim: Drug interference poses great analytical challenges for cell-based neutralizing antidrug antibodies (NAb) assay. The work aimed to improve assay drug tolerance through biotin-drug extraction with acid dissociation method optimization and developing new approach. Results: The NAb extraction with biotin-drug extraction with acid dissociation approach has been optimized by reducing biotinylated drug leaching and improving NAb elution efficiency, resulting in drug tolerance of up to 160 μg/ml. To circumvent the low acid elution efficiency of NAb from drug, a novel drug depletion approach was developed, which combined acid dissociation and drug targeted crosslinked capture, achieved drug tolerance up to 400 μg/ml. At last, a strategy workflow for sample pretreatment approach selection and optimization was established for improving drug tolerance of NAb assay. Conclusion: We demonstrated that reduced biotinylated drug leaching and the high NAb elution efficiency was critical for improving assay drug tolerance. Drug depletion offers an alternative approach to overcome low NAb elution efficiency.

Selected aspects of infectious disease evolution in the modern world

The article presents current views on the evolution of infectious processes and the role of infectious diseases in global healthcare. The reversion of the main components of epidemic processes leads to an atypical course of many infectious diseases and to the emergence of new transmission pathways. Urbanisation, global climate change, agroindustrial boost, migration waves and other factors provoked a cross-border expansion of many wild focal infections across countries and continents. The high morbidity and mortality of infectious diseases are determined by novel and “resurrecting” infections. The possibility of appearing both epidemic and pandemic outbreaks of emergent infections is as relevant as ever.In this context, the impact of modern scientific achievements on environmental microbiotic associations and human microbiome, as well as safety of medical technologies, is of paramount importance.Despite current progress in the drug therapy of infectious diseases, a serious emerging challenge is amplified antimicrobial resistance and drug interference.