Case report: Success of allogeneic hematopoietic stem cell transplantation for refractory systemic-onset juvenile idiopathic arthritis

Objectives

This study reports cases of systemic-onset juvenile idiopathic arthritis (sJIA) who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) at our center and reviews published outcomes of allo-HSCT in sJIA.

Methods

We present a case report of two patients with sJIA who underwent allo-HSCT at a tertiary pediatric hospital. Each patient's disease course and allo-HSCT protocol/outcome are described. Outcomes of published cases of allo-HSCT in sJIA were compared to our experience.

Results

Two patients with sJIA had allo-HSCT. Both failed multiple lines of disease-modifying anti-rheumatic drugs and experienced severe disease/treatment-related complications. Despite post-HSCT complications, both recovered without sequelae. Five years post-HSCT, patient 1 is in complete remission (CR) and is off medications. Patient 2 was in CR until 11 months post-HSCT after which he developed three disease flares. At 4 years post-HSCT he is currently in CR on Adalimumab monotherapy. Engraftment was excellent with a donor chimerism of 100% for patient 1 and 93% for patient 2. In the literature, the outcome of allo-HSCT is reported in 13 sJIA patients. When merging those with our 2 patients, 1/15 patients died and 13/14 achieved CR, of which 12 are off medications (median [range] follow-up: 2.2 [0.2-7.0] years). Extended follow-up data on 11 of the 13 reported sJIA patients showed that an additional 3 patients flared at 3, 4, and 10 years post-HSCT.

Conclusion

We report two patients with severe/refractory sJIA who underwent successful allo-HSCT and achieved CR. Allo-HSCT is a potential curative option for severe/refractory sJIA. It should be considered only after failure of conventional sJIA treatments and when an HLA-matched donor is available in order to lower transplant-related mortality. The outcomes of reported sJIA patients who received allo-HSCT are encouraging but long-term follow-up data are needed to better characterized the risk-benefit ratio of this procedure.

Abatacept to induce remission of peanut allergy during oral immunotherapy (ATARI): protocol for a phase 2a randomized controlled trial

Context

While oral immunotherapy (OIT) has been shown to promote the remission of mild peanut allergy in young children, there is still an unmet need for a disease-modifying intervention for older patients and those with severe diseases. In mice models, abatacept, a cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) immunoglobulin fusion protein, has been shown to promote immune tolerance to food when used as an adjuvant to allergen immunotherapy. The goal of this study is to explore the potential efficacy of abatacept in promoting immune tolerance to food allergens during OIT in humans.

Methods

In this phase 2a proof-of-concept study (NCT04872218), 14 peanut-allergic participants aged from 14 to 55 years will be randomized at a 1:1 ratio to abatacept vs. placebo for the first 24 weeks of a peanut OIT treatment (target maintenance dose of 300 mg peanut protein). The primary outcome will be the suppression of the OIT-induced surge in peanut-specific IgE/total IgE at 24 weeks, relative to the baseline. Sustained unresponsiveness will be assessed as a secondary outcome starting at 36 weeks by observing incremental periods of peanut avoidance followed by oral food challenges.

Discussion

This is the first study assessing the use of abatacept as an adjuvant to allergen immunotherapy in humans. As observed in preclinical studies, the ability of abatacept to modulate the peanut-specific immune response during OIT will serve as a proxy outcome for the development of clinical tolerance, given the small sample size. The study will also test a new patient-oriented approach to sustained tolerance testing in randomized controlled trials.

Mapping the Food Allergy Quality of Life Questionnaire Parent Form onto the Short-Form Six-Dimensions version 2

BACKGROUND

The Food Allergy Quality of Life Questionnaire Parent Form (FAQLQ-PF) is the most widely used quality of life questionnaire in food allergy. The objective of this study was to develop a mapping algorithm to convert FAQLQ-PF scores into health state utilities.

METHODS

The Short-Form Six-Dimensions version 2 (SF-6Dv2) and FAQLQ-PF questionnaires were collected from an academic center oral immunotherapy referral cohort. Utility estimates were derived from the SF-6Dv2 using the food allergy preference set. Candidate mapping algorithm models were developed using seven regression methods starting from either the total average score, the average scores of each of the three domains or the individual item scores of FAQLQ-PF. The process was repeated twice, including only section A, common to all age groups, or including all age-applicable sections of the FAQLQ-PF. The mean absolute error (MAE) and root mean squared error (RMSE) were used to select the best fitting model. An independent cohort from a previous national online survey was used for external validation.

RESULTS

In the index cohort, 1000 of 1257 respondents had completed both questionnaires. The lowest MAE (0.0791) and RMSE (0.1020) were recorded when entering individual item scores in a categorical regression model. The model including only FAQLQ-PF section A was found to be most consistent when tested in the external validation cohort (n = 248) (MAE of 0.0898).

CONCLUSION

The FAQLQ-PF was mapped onto SF-6Dv2 utilities with good predictive accuracy in two independent cohorts. This will enable calculation of health utility for cost-effectiveness analyses in food allergy.

Potential Efficacy of High-Dose Inhaled Salbutamol for the Treatment of Abdominal Pain During Oral Food Challenge

BACKGROUND

Abdominal pain is a frequent symptom of IgE-mediated food allergy with limited therapeutic options. Visceral smooth muscle cell relaxation can be induced through beta-adrenergic stimulation.

OBJECTIVE

To evaluate the efficacy of inhaled salbutamol empirically used to relieve abdominal pain caused by IgE-mediated allergic reactions at 1 center.

METHODS

All double-blind placebo-controlled food challenges to peanut performed at 1 center between 2016 and 2021 were reviewed to identify patients who presented abdominal pain as part of their reaction. The primary outcome measure was the delay between the initiation of therapy and improvement of abdominal pain. It was compared between patients who had received inhaled salbutamol as part of their treatment and those who did not. Cox regression was performed to control for potential confounders.

RESULTS

During the study period, 186 positive double-blind placebo-controlled food challenges were performed, including 126 for peanut allergy. Of these, 77 were treated for abdominal pain and 57 met the criteria for inclusion in the study. Patients who received salbutamol improved significantly faster (median, 12.5 minutes) than those who did not (median, 65 minutes) (χ² = 45; P < .0001). In Cox regression, the administration of salbutamol and emesis were found to increase the rate of improvement by a hazard ratio of 11.35 (95% CI, 5.40-23.9; P < .0005) and 4.00-fold (95% CI, 1.90-8.42; P < .0005), respectively.

CONCLUSIONS

This retrospective study provides hypothesis-generating evidence for the use of salbutamol in the treatment of IgE-mediated abdominal pain. Further investigation in a double-blind randomized controlled trial is warranted.

SF-6Dv2 preference value set for health utility in food allergy

BACKGROUND

The lack of a value set allowing the calculation of QALY is an important limitation when establishing the value of emerging therapies to treat food allergy. The aim of this study was to develop a Short-Form Six-Dimension version 2 (SF-6Dv2) preference value set for the calculation of health utility from the Canadian food-allergic population.

METHODS

Two hundred ninety-five parents of patients aged 0-17 years old and 154 patients aged 12 years old and above with food allergy were recruited in clinic and online. Participants were asked to complete a self-administered online questionnaire including generic health-related quality of life questionnaires. Various health states described by the SF-6Dv2 were valued with time-trade-off and discrete choice experiments. Data from elicitation techniques were combined using the hybrid regression model.

RESULTS

A total of 241 parents and 125 patients performed 3904 time-trade-off and 5112 discrete choice experiments. Utility decrements were estimated for each level of each SF-6Dv2 dimension. Utility values calculated based on the validated preference set were in average 0.15 lower (95%CI: 0.12-0.18) and were poorly correlated (R²  = 0.46) with those derived from the EQ-5D-5L generic questionnaire in the same cohort.

CONCLUSION

A representative preference value set for patients with food allergy was determined using the SF-6Dv2 generic questionnaire. This adapted preference set will contribute to improve the validity of future utility estimates in this population for the appraisal of upcoming potentially impactful but sometimes costly therapies.

Determinants of omalizumab dose-related efficacy in oral immunotherapy: Evidence from a cohort of 181 patients

BACKGROUND

Omalizumab has been shown to improve the safety and feasibility of oral immunotherapy (OIT), but the optimal dosage strategy is unknown.

OBJECTIVE

Our aim was to identify determinants of omalizumab dose-related efficacy in the context of OIT.

METHODS

The study sample consisted of a clinical cohort of 181 patients treated with omalizumab-enabled oral immunotherapy at 3 centers. Patients received omalizumab for at least 2 months before an initial food escalation (IFE) with a mix of up to 6 allergens. Progression through IFE steps was assessed with survival analysis. Continued food dose tolerance with omalizumab weaning was also documented.

RESULTS

Omalizumab dosage per weight alone was strongly associated with progression through the IFE (χ² = 28.18; P < .0001), whereas the standard dosage per weight and total IgE level used for asthma was not (χ² = 0.001; P = .97). When the values at time of IFE were estimated through pharmacokinetics and pharmacodynamics simulation, IFE outcome was best predicted by a model that includes levels of free allergen-specific IgE and their interaction with blocking omalizumab-IgE complexes and free omalizumab levels in serum (χ² = 65.84; degrees of freedom [df] = 2; P < .0005). The occurrence of immediate-type reactions to food dosing subsequent to weaning of omalizumab was associated with a greater ratio of specific IgE level to total IgE level at baseline (geometric mean 0.39 vs 0.16 in those without symptom; P < .0001).

CONCLUSION

In the context of OIT and IgE-mediated disease, omalizumab dosages should be adjusted for body weight alone, independently of total IgE level. The fraction of allergen-specific/total IgE may be useful to predict patients at greater risk of food dosing reactions subsequent to weaning.

Sensitivity and specificity of double-blinded penicillin skin testing in relation to oral provocation with amoxicillin in children

Current recommendations for the management of penicillin allergy are to perform penicillin skin testing (PST) with penicilloyl-polylysine (PPL) and benzylpenicillin (BP) prior to drug challenge with amoxicillin. However, the role of PST is increasingly questioned in the pediatric setting. To resolve the question of PST’s diagnostic accuracy, consecutive children with a history of non-life-threatening penicillin allergy referred to a tertiary-care allergy center were recruited to undergo double-blinded PST with PPL and BP prior to drug provocation to amoxicillin. Five of 158 participants (3.2%) presented with an immediate or accelerated reaction upon amoxicillin challenge, none of which were severe. Only one of these had positive PST (20%), compared to 15 of 153 amoxicillin tolerant participants (9.8%). The sensitivity and specificity of PST with PPL and BP for reacting upon amoxicillin challenge were 20% (95% CI: 0.5–71.6%) and 90% (95% CI: 84.4–94.4%), respectively. These results argue against the routine use of PST as a preliminary step to drug provocation with amoxicillin in this population, as it is unlikely to significantly alter pre-test probability of reacting to challenge.

Protocol for a double-blind, randomized controlled trial on the dose-related efficacy of omalizumab in multi-food oral immunotherapy

Background

Previous proof-of-concept studies have shown that a short course of omalizumab can safely accelerate the oral immunotherapy schedule for multiple allergens simultaneously. Considering the high cost of medication, the dose-related efficacy of omalizumab at decreasing the duration of oral immunotherapy up-dosing phase must be objectively quantified before cost–benefit analyses can be performed. The primary objective of this trial will be to compare the efficacy of 2 omalizumab dosages to placebo at decreasing time-to-maintenance dose during a symptom-driven multi-food OIT protocol.

Methods

A total of 90 participants aged 6 to 25 with multiple food allergies (3 or more) will be enrolled at four sites in Canada. Participants will be randomized to: (A) Omalizumab 8 mg/kg per month (n = 36); (B) Omalizumab 16 mg/kg per month (n = 36); or (C) Placebo (n = 18). Study drug will be administered at full dosage for 12 weeks, then progressively tapered at 50% dosage (8 mg/kg vs 4 mg/kg vs placebo) for 4 weeks and at 25% dosage (4 mg/kg vs 2 mg/kg vs placebo) for another 4 weeks. After a pre-treatment period of 8 weeks, participants will undergo an initial food escalation (IFE) to an OIT mix containing 3 allergens and start daily home dosing with biweekly increases until a target daily maintenance of 1500 mg protein is achieved. The amount escalated at each visit will vary based on treatment tolerance according to a standardized up-dosing algorithm. Participants will be followed for at least 12 months following the initial food escalation. The primary endpoint will be time from IFE to the target maintenance dose of 1500 mg protein. Time-to-event analytic methods, including the log-rank test, will be used to compare the 3 arms.

Discussion

This trial uses a novel pragmatic approach to compare OIT with omalizumab to OIT without omalizumab in a blinded manner, which allows to single out the effect of this anti-IgE medication on treatment effectiveness speed without the recourse to predetermined schedules. The innovative patient-centered up-dosing algorithm allows to maximise treatment effectiveness speed without compromising patient safety, regardless of whether the patient is on omalizumab or not. This study will also provide novel prospective data to inform on the optimal and most cost-effective dosage for this indication.

Trial registration ClinicalTrials.gov, NCT04045301, Registered 5 August 2019, https://clinicaltrials.gov/ct2/show/NCT04045301