Efficacy of a Clinical Decision Rule to Enable Direct Oral Challenge in Patients With Low-Risk Penicillin Allergy: The PALACE Randomized Clinical Trial.

Importance: Fewer than 5% of patients labeled with a penicillin allergy are truly allergic. The standard of care to remove the penicillin allergy label in adults is specialized testing involving prick and intradermal skin testing followed by an oral challenge with penicillin. Skin testing is resource intensive, limits practice to specialist-trained physicians, and restricts the global population who could undergo penicillin allergy delabeling. Objective: To determine whether a direct oral penicillin challenge is noninferior to the standard of care of penicillin skin testing followed by an oral challenge in patients with a low-risk penicillin allergy. Design, Setting, and Participants: This parallel, 2-arm, noninferiority, open-label, multicenter, international randomized clinical trial occurred in 6 specialized centers, 3 in North America (US and Canada) and 3 in Australia, from June 18, 2021, to December 2, 2022. Eligible adults had a PEN-FAST score lower than 3. PEN-FAST is a prospectively derived and internationally validated clinical decision rule that enables point-of-care risk assessment for adults reporting penicillin allergies. Interventions: Patients were randomly assigned to either direct oral challenge with penicillin (intervention arm) or a standard-of-care arm of penicillin skin testing followed by oral challenge with penicillin (control arm). Main Outcome and Measure: The primary outcome was a physician-verified positive immune-mediated oral penicillin challenge within 1 hour postintervention in the intention-to-treat population. Noninferiority was achieved if a 1-sided 95% CI of the risk difference (RD) did not exceed 5 percentage points (pp). Results: A total of 382 adults were randomized, with 377 patients (median [IQR] age, 51 [35-65] years; 247 [65.5%] female) included in the analysis: 187 in the intervention group and 190 in the control group. Most patients had a PEN-FAST score of 0 or 1. The primary outcome occurred in 1 patient (0.5%) in the intervention group and 1 patient (0.5%) in the control group, with an RD of 0.0084 pp (90% CI, -1.22 to 1.24 pp). The 1-sided 95% CI was below the noninferiority margin of 5 pp. In the 5 days following the oral penicillin challenge, 9 immune-mediated adverse events were recorded in the intervention group and 10 in the control group (RD, -0.45 pp; 95% CI, -4.87 to 3.96 pp). No serious adverse events occurred. Conclusions and Relevance: In this randomized clinical trial, direct oral penicillin challenge in patients with a low-risk penicillin allergy was noninferior compared with standard-of-care skin testing followed by oral challenge. In patients with a low-risk history, direct oral penicillin challenge is a safe procedure to facilitate the removal of a penicillin allergy label. Trial Registration: ClinicalTrials.gov Identifier: NCT04454229.

Updated guidance regarding the risk of allergic reactions to COVID-19 vaccines and recommended evaluation and management: A GRADE assessment and international consensus approach.

This guidance updates 2021 GRADE (Grading of Recommendations Assessment, Development and Evaluation) recommendations regarding immediate allergic reactions following coronavirus disease 2019 (COVID-19) vaccines and addresses revaccinating individuals with first-dose allergic reactions and allergy testing to determine revaccination outcomes. Recent meta-analyses assessed the incidence of severe allergic reactions to initial COVID-19 vaccination, risk of mRNA-COVID-19 revaccination after an initial reaction, and diagnostic accuracy of COVID-19 vaccine and vaccine excipient testing in predicting reactions. GRADE methods informed rating the certainty of evidence and strength of recommendations. A modified Delphi panel consisting of experts in allergy, anaphylaxis, vaccinology, infectious diseases, emergency medicine, and primary care from Australia, Canada, Europe, Japan, South Africa, the United Kingdom, and the United States formed the recommendations. We recommend vaccination for persons without COVID-19 vaccine excipient allergy and revaccination after a prior immediate allergic reaction. We suggest against >15-minute postvaccination observation. We recommend against mRNA vaccine or excipient skin testing to predict outcomes. We suggest revaccination of persons with an immediate allergic reaction to the mRNA vaccine or excipients be performed by a person with vaccine allergy expertise in a properly equipped setting. We suggest against premedication, split-dosing, or special precautions because of a comorbid allergic history.

Hypersensitivity reactions to biologics in children.

INTRODUCTION: Hypersensitivity reactions (HSRs) have been observed with the use of biologics in children. The management of HSRs in children is mainly based on experiences from the adult population. Recently, data from different centers experienced in managing these reactions, including desensitization in children, have been published, allowing clinicians to have an appropriate global overview and compare results. AREAS COVERED: This review highlights the published data on hypersensitivity reactions to biologics in children and drug desensitization protocols adapted to the pediatric population. EXPERT OPINION: With regard to HSRs to biologics in children, few data are available. Compared with the adult population, there is a lack of knowledge in the endophenotypes, management and the standardization of protocols including premedication regimens in children. An international consensus is needed to provide clinicians with new insight on how to apply personalized management and to perform tailored desensitization protocols in pediatric populations. Various specialists including allergists, pediatricians, oncologists, hematologists, rheumatologists, and pharmacists, should build a multidisciplinary management team to keep pediatric patients on their best treatment options in the safest manner.

Allergic reactions to the coronavirus disease 2019 vaccine (ARCOV) study: The McGill University Health Centre experience.

BACKGROUND: Messenger RNA coronavirus disease 2019 (COVID-19) vaccines have been associated with allergic reactions. A history of anaphylaxis has been suggested as a risk factor for such reactions. Polyethylene glycol (PEG) has been proposed as a possible culprit allergen. OBJECTIVE: To investigate possible PEG or polysorbate allergy among patients reporting prior reactions to COVID-19 vaccines or PEG and to report their subsequent tolerance of COVID-19 vaccines. METHODS: From January 1, 2021, to October 31, 2021, adult patients referred to the McGill University Health Centre allergy clinics who were considered at risk of anaphylaxis were prospectively recruited. The entry criteria were any documented history of reaction to a COVID-19 vaccine or reported allergy to PEG or polysorbate. Evaluated patients underwent skin prick testing (SPT) with PEG and polysorbate. After SPT, placebo-controlled vaccine challenges were carried out. RESULTS: Of the 44 patients recruited, 40 (90.1%) had reacted to the first vaccine dose, with 18 (45%) of them had anaphylactic reaction. All patients underwent SPT and 5 (11.3%) had a positive test result. A total of 39 patients (88.6%) underwent COVID-19 vaccine challenge at the allergy clinic. Most tolerated the vaccine, with 18 (40.1%) received a single full dose, 20 (45.4%) 2 split doses, and 6 (13.6%) a graded dosing protocol. Of the 40 patients who reacted to the first dose, 2 had immediate nonsevere allergic reactions to the second dose. CONCLUSION: In this cohort of patients with a history of anaphylaxis and increased risk of allergic reactions to the COVID-19 vaccines, after allergist evaluation, including negative PEG skin testing result, the vaccine was safely administered without any serious adverse events.

Successful Desensitization to mRNA COVID-19 Vaccine in a Case Series of Patients With a History of Anaphylaxis to the First Vaccine Dose.

Background: Coronavirus disease 2109 (COVID-19) vaccines have recently been approved to curb the global pandemic. The risk of allergic reactions to the vaccine polyethylene glycol (PEG) component has raised significant public concern. Desensitization is suggested in cases of vaccine related hypersensitivity reactions. After comprehensive literature review on the topic, our aim was to establish a safe and effective desensitization protocol for patients with suspected or confirmed immediate type hypersensitivity reactions to the COVID-19 vaccine. Methods: Participants were referred to the McGill University Health Center (MUHC) Allergy-Immunology department for clinical evaluation following a reported reaction to their first dose of Moderna® mRNA-1273 or Pfizer-BioNTech® BNT162b2 vaccines. They underwent skin prick testing (SPT) with higher and lower molecular weight (MW) PEG and polysorbate 80, as per published protocols. Their second dose was administered following a desensitization protocol consisting of multiple dose-administration steps followed by a 60-min observation period. Results: Among a cohort of 142 patients with an increased risk for allergic reactions to the COVID-19 vaccines, six individuals were selected to undergo desensitization. All were female with allergic background including chronic spontaneous urticaria, anaphylaxis to medications, and/or vaccines. The main symptom after their first dose was difficulty swallowing with lightheadedness or immediate urticaria, angioedema, and/or dizziness. Two patients had positive skin testing. One patient was on chronic antihistamines which resulted in an inconclusive PEG skin test and the skin testing was negative for the three other patients. During the desensitization, two patients reported cutaneous symptoms of an immediate reaction and were managed with antihistamines. One of these patients also complained of ear pressure and had a drop in her systolic blood pressure, treated with intravenous fluids. Conclusion: This study suggests that some individuals with an immediate-type hypersensitivity reaction to their first dose of mRNA COVID-19 vaccine may safely receive their second dose using a desensitization protocol. The success of this desensitization protocol is a step forward in the fight against COVID-19, allowing more individuals to be immunized.

Premedication Protocols to Prevent Hypersensitivity Reactions to Chemotherapy: a Literature Review.

Hypersensitivity reactions (HSRs) to chemotherapy may prevent patients from receiving the most effective therapy. This review was undertaken to identify evidence-based preventive premedication strategies that reduce the likelihood of HSR in the first instance and improve the safety of subsequent infusions in patients who have demonstrated HSR to a certain class of chemotherapy. PubMed was searched until October 2021 using the key words: "hypersensitivity to chemotherapeutic drugs," "hypersensitivity to antineoplastic agents," "taxanes hypersensitivity," "platinum compound hypersensitivity," "premedication," "dexamethasone," "prednisone," "hydrocortisone," "antihistamine," "diphenhydramine," "cetirizine," "famotidine," "meperidine," "aspirin," "ibuprofen," and "montelukast." The search was restricted to articles published in English. A total of 73 abstracts were selected for inclusion in the review. Most premedication regimens have been derived empirically rather than determined through randomized trials. Based on the available evidence, we provide an update on likely HSR mechanisms and a practical guide for classifying systemic HSR. The evidence indicates that a combination of prevention strategies using newer antihistamines, H2 antagonists, leukotriene receptor antagonists, and corticosteroids and other interventions used judiciously reduces the occurrence and severity of HSR and improves safety.

Hypersensitivity reactions to therapeutic monoclonal antibodies: Phenotypes and endotypes.

BACKGROUND: The increasing use of mAbs has led to a rise in hypersensitivity reactions (HSRs), which prevent their use as first-line therapy. HSRs' symptoms, diagnostic tools, and directed management approaches have not been standardized. OBJECTIVE: We propose a novel evidence-based classification of HSRs to mAbs, based on the clinical phenotypes, underlying endotypes and biomarkers, as well as their management with desensitization. METHODS: Phenotypes, endotypes, and biomarkers of HSRs to 16 mAbs for 104 patients were described and compared with the outcomes of 526 subcutaneous and intravenous desensitizations. RESULTS: Initial reactions presented with 4 patterns: type I-like reactions (63%), cytokine-release reactions (13%), mixed reactions (21%), and delayed type IV reactions (3%). In contrast, of the 23% breakthrough HSRs during desensitization, 52% were cytokine-release reactions, 32% were type 1, 12% were mixed, and 4% were type I with delayed type IV. Skin testing to 10 mAbs in 58 patients was positive in 41% of patients. Serum tryptase was elevated in 1 patient and IL-6 was elevated in 8 patients during desensitization and was associated with a cytokine-release phenotype. CONCLUSIONS: HSRs to mAbs can be defined as type I, cytokine-release, mixed (type I/cytokine-release), and type IV reactions, which are identified by biomarkers such as skin test, tryptase, and IL-6. These phenotypes can be used to improve personalized and precision medicine when diagnosing HSRs to mAbs and providing management recommendations with desensitization. Desensitization provides a safe and effective retreatment option to remain on culprit mAbs as first-line therapy.

Management of adverse reactions to biologic agents.

Hypersensitivity reactions (HSR) to targeted biologic agents present as immediate reactions during infusion or as delayed reactions (after one or more exposures). The new classification includes phenotypes, endotypes, and biomarkers. Phenotypes include immediate type I (immunoglobulin E [IgE] or non-IgE mediated), cytokine release, mixed (type I/cytokine), and immune complexes type III (IgG mediated) reactions as well as delayed type IV reactions. Endotypes include IgE or non-IgE mediated mast cells/basophils activation with elevated serum tryptase and T cells values as well as macrophages, which lead to cytokine production, e.g., interleukin 6. A skin test is a valuable tool in evaluating HSRs to biologics; however, its predictive value depends on the type of reaction and the monoclonal antibody. Desensitization is a new approach to safely reintroduce biologics when they are first-line therapies, and it is available for immediate and delayed reactions. Research is needed to further understand the mechanisms of reactions to monoclonal antibodies and their management.

A population-based assessment of the burden of acute pancreatitis in the United States.

OBJECTIVES: The aim of this study is to investigate the incidence and mortality of emergency department (ED) visits in the United States attributed to acute pancreatitis (AP) and quantify predictors of admission and mortality. METHODS: Using the nationwide ED sample, all ED visits between 2006 and 2009 for AP were extracted. Multivariable analyses were fitted for prediction of admission and mortality. RESULTS: A weighted sample of 1,224,121 patient visits with AP was captured. Of those, 75.4% resulted in admission and 0.7% died. Between 2006 and 2009, the incidence of AP ED visits increased from 9.9 to 10.6 per 10,000 person-years. Patients were more likely to be admitted if sicker (Charlson Comorbidity Index score ≥ 3; OR, 6.48; P < 0.001) and if the etiology of pancreatitis was alcoholic versus biliary (OR, 2.20; P < 0.001). They were more likely to die if sicker (Charlson Comorbidity Index score ≥ 3; OR, 1.51; P < 0.001) and covered with Medicare or Medicaid versus private insurance (OR, 1.40; P < 0.001 and OR, 1.45; P < 0.001, respectively). CONCLUSIONS: Emergency department visits for AP represent a significant burden on US health care. Although mortality is lower than previously reported, significant disparities exist in patients presenting with AP with regard to admission and mortality rates. Further investigations are needed to assess these disparities.