Safety, tolerability, and activity of the active C1s antibody riliprubart in cold agglutinin disease: a phase 1b study.

ABSTRACT: Cold agglutinin disease is a rare autoimmune hemolytic anemia characterized by complement pathway-mediated hemolysis. Riliprubart (SAR445088, BIVV020), a second-generation classical complement inhibitor, is a humanized monoclonal antibody that selectively inhibits only the activated form of C1s. This Phase 1b study evaluated the safety, tolerability, and effect on hemolysis of riliprubart in adult patients with cold agglutinin disease. On day 1, 12 patients received a single IV dose of either 30 mg/kg (n = 6) or 15 mg/kg (n = 6) of riliprubart and were subsequently followed for 15 weeks. Riliprubart was generally well tolerated; there were no treatment-emergent serious adverse events, or treatment-emergent adverse events leading to death or permanent study discontinuation. There were no reports of serious infections, encapsulated bacterial infections including meningococcal infections, hypersensitivity, or thromboembolic events. Rapid improvements in hemoglobin (day 5) and bilirubin (day 1) were observed in both treatment cohorts. Mean hemoglobin levels were maintained at >11.0 g/dL from day 29 and mean levels of bilirubin were normalized by day 29; both responses were maintained throughout the study. Improvements in clinical markers closely correlated with a sustained reduction in the 50% hemolytic complement (CH50) throughout the study. Mean C4 levels, an in vivo marker of treatment activity, increased 1 week after treatment with either dose of riliprubart and were sustained throughout the study. In conclusion, a single IV dose of riliprubart was well tolerated, and led to rapid classical complement inhibition, control of hemolysis, and improvement in anemia, all of which were sustained over 15 weeks. This trial was registered at www.ClinicalTrials.gov as #NCT04269551.

Cephalosporin Allergy: Updates on Diagnostic Testing.

PURPOSE OF REVIEW: Cephalosporins are one of the most prescribed antibiotics worldwide and are implicated in a wide range of hypersensitivity reactions (HSR). This review summarizes recent updates in cephalosporin hypersensitivity with a focus on diagnostic testing. RECENT FINDINGS: Reported testing strategies to evaluate different immediate and delayed cephalosporin HSR have included skin testing, in vitro testing, and diagnostic drug challenges. However, the diagnostic performance of in vivo and in vitro tests remains unclear across different hypersensitivity endotypes; adequately powered studies investigating the true positive and negative predictive value of these diagnostic modalities are needed using the reference standard of drug challenges to define cephalosporin hypersensitivity. Refinement of diagnostic testing should be guided by growth in our understanding of cephalosporin antigenic determinants. This growth will be crucial in driving further clarification of cross-reactivity between cephalosporins, and potentially delineating streamlined evaluation processes resulting in reduced unnecessary antibiotic avoidance.

United States Drug Allergy Registry (USDAR) grading scale for immediate drug reactions.

BACKGROUND: There is no accepted grading system classifying the severity of immediate reactions to drugs. OBJECTIVE: The purpose of this article is to present a proposed grading system developed through the consensus of drug allergy experts from the United States Drug Allergy Registry (USDAR) Consortium. METHODS: The USDAR investigators sought to develop a consensus severity grading system for immediate drug reactions that is applicable to clinical care and research. RESULTS: The USDAR grading scale scores severity levels on a scale of 0 to 4. A grade of no reaction (NR) is used for patients who undergo challenge without any symptoms or signs, and it would confirm a negative challenge result. A grade 0 reaction is indicative of primarily subjective complaints that are commonly seen with both historical drug reactions and during drug challenges, and it would suggest a low likelihood of a true drug allergic reaction. Grades 1 to 4 meet the criteria for a positive challenge result and may be considered indicative of a drug allergy. Grade 1 reactions are suggestive of a potential immediate drug reaction with mild symptoms. Grade 2 reactions are more likely to be immediate drug reactions of moderate severity. Grade 3 reactions have features suggestive of a severe allergic reaction, whereas grade 4 reactions are life-threatening reactions such as anaphylactic shock and fatal anaphylaxis. CONCLUSION: This proposed grading schema for immediate drug reactions improves on prior schemata by being developed specifically for immediate drug reactions and being easy to implement in clinical and research practice.

Safety of subcutaneous immunotherapy in patients with severe asthma.

BACKGROUND: Severe asthma (SA) has been identified as a risk factor for severe systemic reactions (SR) to allergen subcutaneous immunotherapy (SCIT). However, the incidence and characterization of SRs in SA in comparison to less severe or no asthma is not known. OBJECTIVE: The objective of this study was to characterize the incidence of SRs in patients with SA receiving SCIT in comparison to patients with no asthma or less SA. METHODS: A retrospective cohort study was performed on patients receiving SCIT from a multicenter national network of private allergy practices between January 2015 and December 2019. Demographics, asthma severity (International Classification of Diseases-10 codes), concomitant medications, aeroallergen skin testing, measures of asthma control with the asthma control test and forced expiratory volume in 1 second values, SCIT prescription, and an SR standardized form were assessed. RESULTS: A total of 65,855 patients, with 1072 patients having SA receiving SCIT, were included with a total of 4415 SRs (19.9 SR per 10,000 injection visits). Severe asthma had 23.9 SRs per 10,000 injection visits (incidence rate, 0.239; 95% confidence interval [0.189-0.298]). There were 155 grade III or IV SRs; 5 (3.2%) occurred in the SA group. There was no difference in rates of grade III or IV SRs between SA and no asthma and in rates of total SRs between SA and less SA. CONCLUSION: In a large cohort of patients with SA undergoing multiallergen SCIT drawn from a diverse outpatient allergy population, the diagnosis of SA was not associated with increased moderate-severe SRs compared with patients without asthma and any severity of asthma.

Adverse Reactions to Biologic Medications Used in Allergy and Immunology Diseases.

PURPOSE OF REVIEW: The use of biologic therapies has risen exponentially over recent years, allowing for unprecedented disease control within numerous areas of Allergy/Immunology. With this expanded use, awareness and understanding of adverse reactions to biologic agents have also increased. RECENT FINDINGS: Multiple biologic adverse reaction phenotypes have been described, but significant overlap in clinical features across phenotypes exists. Given considerable phenotypic overlap, a targeted testing approach may not always be clear, and more recent classifications focus on management decision making using tools of diagnostic challenges and rapid drug desensitizations, guiding clinicians in developing a management plan when the exact underlying mechanism is not clearly known. With increased clinical experience with omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, tezepelumab, rituximab, and TNF-inhibitors, there is a growing appreciation to the spectrum and particularities of adverse reactions to these agents which are outlined in this review. Our understanding of the clinical presentation and management of adverse reactions to biologic medications encountered in Allergy/Immunology has grown. Opportunities remain to further define optimal diagnostic and management strategies for these reactions.

Perioperative Outcomes of Robot-Assisted Radical Cystectomy with Intracorporeal Versus Extracorporeal Urinary Diversion.

PURPOSE: This study was designed to investigate and compare the perioperative outcomes of intracorporeal urinary diversion (ICUD) versus extracorporeal urinary diversion (ECUD) following robotic-assisted radical cystectomy (RARC) in patients with localized bladder cancer from the Asian Robot-Assisted Radical Cystectomy (RARC) Consortium. METHODS: The Asian RARC registry was a multicenter registry involving nine centers in Asia. Consecutive patients who underwent RARC were included. Patient and disease characteristics, intraoperative details, and perioperative outcomes were reviewed and compared between the ICUD and ECUD groups. Postoperative complications were the primary outcomes, whereas secondary outcomes were the estimated blood loss and the duration of hospitalization. Multivariate regression analyses were performed to adjust potential confounders. RESULTS: From 2007 to 2020, 556 patients underwent RARC; 55.2% and 44.8% had ICUD and ECUD, respectively. ICUD group had less estimated blood loss (423.1 ± 361.1 vs. 541.3 ± 474.3 mL, p = 0.002) and a shorter hospital stay (15.7 ± 12.3 vs 17.8 ± 11.6 days, p = 0.042) than the ECUD group. Overall complication rates were similar between the two groups. Upon multivariate analysis, ICUD was associated with less estimated blood loss (Regression coefficient: - 143.06, 95% confidence interval [CI]: - 229.60 to - 56.52, p = 0.001) and a shorter hospital stay (Regression coefficient: - 2.37, 95% CI: - 4.69 to - 0.05, p = 0.046). In addition, ICUD was not associated with any increased risks of minor, major, and overall complications. CONCLUSIONS: RARC with ICUD was safe and technically feasible with similar postoperative complication rates as ECUD, with additional benefits of reduced blood loss and a shorter hospitalization.

A 2-year-old girl with periprocedural anaphylaxis.

Periprocedural or perioperative anaphylaxis is rare, with an estimated incidence of 1 in 10,000 to 40,000 sedation cases. During such procedures, patients are often exposed to numerous medications, such as antimicrobials, neuromuscular blocking agents, sedative and/or hypnotics, and opioids. The most commonly implicated agents include antibiotics (in the United States) and neuromuscular blocking agents (in Europe). In this article, we explore the differential diagnosis and laboratory investigation of a case of periprocedural anaphylaxis.

POPs Case Report: A 2-year-old girl with periprocedural anaphylaxis.

Periprocedural or perioperative anaphylaxis is rare, with an estimated incidence of 1 in 10,000 to 40,000 sedation cases.During such procedures, patients are often exposed to numerous medications, such as antimicrobials, neuromuscular blockingagents, sedative and/or hypnotics, and opioids. The most commonly implicated agents include antibiotics (in the UnitedStates) and neuromuscular blocking agents (in Europe). In this article, we explore the differential diagnosis and laboratoryinvestigation of a case of periprocedural anaphylaxis.

Postnatal outcomes in lambs exposed antenatally and acutely postnatally to fluoxetine.

BACKGROUND: Approximately 1/3 of newborns exposed antenatally to selective serotonin reuptake inhibitors (SSRIs) exhibit poor neonatal adaptation. Although several potential mechanisms have been proposed, the actual mechanism has not been elucidated. METHODS: We investigated outcomes in neonatal lambs exposed prenatally or postnatally to fluoxetine (FX). Daily FX injections (50 mg) were given intravenously (i.v.) to five pregnant ewes via implanted catheters beginning at 131-132 days gestation (term = 147 days) for 2 weeks. In another group, lambs with implanted vascular catheters had sterile water (n = 9) or FX (1 mg/kg, n = 12) injected i.v. on ~postnatal day (PND) 4. RESULTS: Prenatal FX-exposed lambs (n = 7) were hyperactive during PND 4 to 14 and their heart rate variability (HRV) was significantly lower than in control lambs (n = 7) on PND 2. In contrast, arterial pressure, heart rate, electrocardiogram, arterial blood gases, pH, glucose, lactate, cortisol, and sleep-activity cycles were not altered following postnatal FX injection. CONCLUSION: This abnormal postnatal hyperactivity with antenatal FX exposure may reflect increased maturity in terms of locomotory activity. The results suggest that altered brain development may be involved in the poor neonatal adaptation in human infants exposed to FX in utero.

Evaluation of the predictive performance of physiologically based pharmacokinetic models for intramuscular injections of therapeutic proteins.

Several physiologically-based pharmacokinetic (PBPK) models have been reported for intravenous (IV) and subcutaneous (SC) injections, but there has been a paucity of work for intramuscular (IM) injections. The primary objective of this work was a wide-scale evaluation of the predictive performance of IM PBPK models of therapeutic proteins. PBPK models for all administration routes available in the literature have regarded muscle as the total muscle (TM) in the body; however, anatomically, the body is composed of discrete muscle groups. Clinically, IM is administered to a specific muscle (SM). We explored the predictive performance of IM PBPK models with an SM or TM dosing site. The plasma concentration-time profiles of seven therapeutic proteins after an IM dose in humans served as the clinically observed data for model evaluation - this was a diverse group ranging from 30 to 149 kDa from six protein classes. Pharmacokinetic parameters Cmax, tmax, AUC0-∞, and ka were estimated. SM and TM IM PBPK approaches were compared using Average Fold Error (AFE) and Pearson Chi-Square LineShape analyses. This work represents the first wide-scale validation of IM PBPK models and suggests that these models predict IM PBPK reasonably well. The SM and TM approach provided comparable performance.

An in vivo evaluation of the ontogeny of stereoselective fluoxetine metabolism and disposition in lambs from birth to one year of age.

1. The objective was to determine the ontogeny of stereoselective fluoxetine (FX) disposition in postnatal sheep from newborn to adulthood. 2. Catheters were implanted in a carotid artery and jugular vein. FX was administered intravenously, followed by serial arterial blood and cumulative urine collection. The concentrations of R,S-FX and R,S-norfluoxetine (R,S-NFX) in samples were measured using a validated enantioselective LC/MS/MS analytical method. 3. The metabolism of FX at 4.2 ± 0.4 days was limited compared to adults, but had developed compared to the fetus. Total body clearance (ClTB) did not significantly increase up to 33.6 ± 0.9 days, but significantly increased at 98.5 ± 2.0 days, with no further changes up to 397.3 ± 8.5 days. Up to 13.4 ± 0.8 days, the disposition of FX included Phase I metabolism to NFX and trifluoromethylphenol (TFMP), and renal elimination. At 32.9 ± 0.9 days, metabolism included Phase II conjugates of FX and NFX. Renal elimination of these compounds was low. 4. The elimination of FX increased in a non-linear manner during the first year in sheep. The metabolism and disposition of FX and NFX in plasma and urine were stereoselective and this appeared due to both stereoselective protein binding and metabolism.

Non-IgE-Mediated Immediate Drug-Induced Hypersensitivity Reactions.

Immediate drug-induced hypersensitivity reactions (IDHSRs) have conventionally been attributed to an immunoglobulin E (IgE)-mediated mechanism. Nevertheless, it has now been acknowledged that IDHSRs can also occur independently of IgE involvement. Non-IgE-mediated IDHSRs encompass the activation of effector cells, both mast cell-dependent and -independent and the initiation of inflammatory pathways through immunogenic and nonimmunogenic mechanisms. The IDHSRs involve inflammatory mediators beyond histamine, including the platelet-activating factor, which activates multiple cell types, including smooth muscle, endothelium, and MC, and evidence supports its importance in IgE-mediated reactions in humans. Clinically, distinguishing IgE from non-IgE mechanisms is crucial for future treatment strategies, including drug(s) restriction, readministration approaches, and pretreatment considerations. However, this presents significant challenges because certain drugs can trigger both mechanisms, and their presentations can appear similarly, ranging from mild to life-threatening symptoms. Thus, history alone is often inadequate for differentiation, and skin tests lack a standardized approach. Moreover, drug-specific IgE immunoassays have favorable specificity but low sensitivity, and the usefulness of the basophil activation test remains debatable. Lastly, no biomarker reliably differentiates between both mechanisms. Whereas non-IgE-mediated mechanisms likely predominate in IDHSRs, reclassifying most drug-related IDHSRs as non-IgE-mediated, with suggested prevention through dose administration adjustments, is premature and risky. Therefore, continued research and validated diagnostic tests are crucial to improving our capacity to distinguish between these mechanisms, ultimately enhancing patient care.