Intravenous immunoglobulin 10% in children with primary immunodeficiency diseases

Real-world experience with CLAIRYG® 50 mg/mL (intravenous immunoglobulin) in children under 12 years with primary immunodeficiency or immmune thrombocytopenia: a post-approval safety study

Introduction

This study presents the results of a real-life, multicenter, prospective, post-approval safety evaluation of Clairyg® 50 mg/mL, a 5% intravenous immunoglobulin (IVIg) liquid, in 59 children (aged < 12 years) with primary immunodeficiency diseases (PID) (n = 32) or immune thrombocytopenia (ITP) (n = 27) in France.

Methods

The primary objective of the study was to assess the safety and tolerability of Clairyg®, recording all serious and non-serious adverse events (AEs), whether related (rAEs) or not related to the product. Secondary objectives aimed at evaluating the administration of Clairyg® under routine conditions and the available efficacy data to better document the benefit/risk ratio in this pediatric population. An exploratory objective was added to evaluate the potential factors associated with the occurrence of rAEs. Patients received Clairyg® according to the approved dosage under normal conditions of prescriptions over a median follow-up period of 11.8 months.

Results

A total of 549 infusions (PID: n = 464 and ITP: n = 85), were administered, of which 58.8% were preceded by premedication. The most frequent rAEs were headache, vomiting, and pyrexia in both indications. Most of them were considered non-serious and mild or moderate in intensity. A severe single rAE was observed (aseptic meningitis) in a 4-year-old girl presenting with chronic ITP. The exploratory multivariate analysis of potential co-factors showed that the occurrence of rAEs is significantly linked to high IVIg doses and possibly to female gender. The annualized rate of serious bacterial infections was 0.11 for patients with PID. For patients with ITP, 74.1% experienced at least one bleeding episode during the follow-up, mostly a cutaneous one, and none had gastrointestinal, genitourinary, or central nervous system bleeding.

Conclusion

Clairyg® was well tolerated and allowed for control of serious bacterial infection in PID and serious bleeding in ITP, which are the main complications in these respective pediatric disorders. No new safety signal was detected in children less than 12 years-old in real-life conditions of use.

Low rates of headache and migraine associated with intravenous immunoglobulin infusion using a 15-minute rate escalation protocol in 123 patients with primary immunodeficiency

Introduction

Headache and migraine adverse events are common concerns in the administration of intravenous immune globulins (IVIG). Trials of IVIG for primary immunodeficiency (PI) are typically small and have reported headache and migraine data inconsistently.

Methods

We analyzed headache and migraine in pooled data from three pivotal trials of Gammaplex® 5% and 10% in PI (NCT00278954 from January 18, 2006; NCT01289847 from January 27, 2011; NCT01963143 from September 13, 2013). The trials were pooled in a retrospective analysis that included two 12-month open-label non-comparative trials of the 5% IVIG product and one 6-month open-label crossover bioequivalence trial comparing the 5% IVIG and 10% IVIG products. The population included adult and pediatric patients, who received IVIG infusions of 300-800 mg/kg/infusion every 21 or 28 days using a 15-minute rate escalation protocol.

Results

In total, 1482 infusions were administered to 123 patients, with 94.6% of infusions achieving the maximum infusion rate. At least one product-related headache was reported in 6.1% (90/1482) of infusions. At least one product-related migraine was reported in 0.5% (7/1482) of infusions. Headache rates were higher for adults vs pediatric patients, females vs males, and 21-day vs 28-day dosing schedules, but were similar for the 5% and 10% IVIG products. Most headaches and migraines occurred during or within 72 hours of the infusion. Rates decreased after the first few infusions.

Discussion

Patients receiving this IVIG product on a 15-minute rate escalation protocol had low rates of headache and migraine for both the 5% and 10% formulations.

BT595, a 10% Human Normal Immunoglobulin, for Replacement Therapy of Primary Immunodeficiency Disease: Results of a Subcohort Analysis in Children

PURPOSE

To assess the efficacy, pharmacokinetics, and safety of a new, highly purified 10% IVIg (BT595, Yimmugo^®) administered in children with PID.

METHODS

This was an open-label, prospective, uncontrolled, multicenter Phase III pivotal trial. Among the 67 subjects in the trial were 18 pediatric patients aged 2 to 17 years with diagnosis of PID included in this analysis. They received doses between 0.2 and 0.8 g/kg body weight for approximately 12 months at intervals of either 3 or 4 weeks. Dosage and dosing interval were based on each patient's pre-trial infusion schedule. The rates of acute serious bacterial infections (SBI), secondary efficacy, safety, and pharmacokinetic outcomes were evaluated.

RESULTS

No SBI occurred in the pediatric population. Two hundred sixty infusions were administered to the 18 pediatric patients. The mean (SD) IgG trough level was 8.55 (1.67) g/L at baseline and 8.84 (2.17) g/L at the follow-up visit after the last BT595 infusion. At the single infusions respectively, the average mean IgG trough levels ranged between 8.52 and 10.58 g/L. More than 85% of all infusions administered were not associated with any infusional AE (start during or within 72 h post-infusion). None of the severe or serious AEs were related to the investigational medicinal product (IMP). No premedication was used. Thirteen children reached a maximum infusion rate between > 2.0 and 8 mL/kg/h; no AE with an onset during the infusion occurred at these infusion rates.

CONCLUSION

BT595 is effective, convenient, well tolerated, and safe for the treatment of children with PID.

TRIAL REGISTRATION

EudraCT: 2015-003652-52; NCT02810444, registered June 23, 2016.

Intensive Safety Monitoring of Rituximab (Biosimilar Novex® and the Innovator) in Pediatric Patients With Complex Diseases

Although rituximab is widely used off-label for complex pediatric diseases, safety reports are limited. We aimed to report evidence of its use in clinical practice, to describe the incidence of adverse drug reactions (ADR) to rituximab biosimilar Novex^® and innovator, and to identify risk factors for the development of ADR in a real-life follow-up cohort of pediatric patients with complex diseases. We conducted a prospective, longitudinal, observational, single-centre study in patients that received rituximab for any complex disease, and as part of an intensive pharmacovigilance program. Demographic, pharmacological, clinical, and drug-related data were collected for all patients. ADR-free survival, including infusion-related reactions (IRR) and delayed ADR (dADR), was estimated using Kaplan-Meier curves. Risk factors were evaluated by multivariable Cox regression models. In total, 77 patients (<19 y.o.) received 187 infusions of rituximab Novex^® (n = 155) or innovator rituximab (n = 32) for neurologic (Neu), immune-hematologic-rheumatic (IHR), oncologic (O) diseases, and hematopoietic stem-cell transplantation (HSCT) or solid-organ transplantation (SOT). We recorded 29 IRR and 58 dADR that occurred in 27 (35.1%) and 29 (37.7%) patients, respectively. The respiratory tract was the most affected during IRR (29.6%) and hypogammaglobulinemia (37.9 %) was the most frequent dADR. First versus subsequent infusions (HR 5.4, CI95% 2.4-12.1, p<0.05), sex (boys vs. girls, HR 0.3, CI95% 0.1-0.8, and p<0.05), and diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 2.3, CI95% 1.02-5.4, and p < 0.05) were significantly associated with the development of IRR. For dADR, risk factors were diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 0.4, CI95% 0.2-0.9, and p < 0.05) and cumulative body surface area-normalized dosage (HR 1.0003, CI95% 1.0001-1.0006, and p < 0.05). The present is the largest real-world safety assessment of rituximab in Latin-American children with complex diseases supporting its use based on the overall acceptable safety. Identification of risk factors may contribute to optimization of off-label rituximab treatment in pediatrics.

A systematic review of population pharmacokinetic analyses of polyclonal immunoglobulin G therapy

BACKGROUND

Population pharmacokinetics (popPK) using the nonlinear mixed-effect (NLME) modeling approach is an essential tool for guiding dose individualization. Several popPK analyses using the NLME have been conducted to characterize the pharmacokinetics of immunoglobulin G (IgG).

OBJECTIVE

To summarize the current information on popPK of polyclonal IgG therapy.

METHOD

A systematic search was conducted in the PubMed and Web of Science databases from inception to December 2020. Additional relevant studies were also included by reviewing the reference list of the reviewed articles. All popPK studies that employed the NLME modeling approach were included and data were synthesized descriptively.

RESULTS

This review included seven studies. Most of the popPK models were developed in patients with primary immunodeficiency (PID). IgG pharmacokinetics was described as a two-compartment model in five studies, while it was described as a one-compartment model in two other studies. Among all tested covariates, weight was consistently identified as a significant predictor for clearance (CL) of IgG. Whereas, weight and disease type were found to be significant predictors for the volume of distribution in central compartment (Vc). In a typical 70 kg adult, the median estimated values of Vc and CL were 4.04 L and 0.144 L/day, respectively. The between subject variability of Vc was considered large. Only two studies evaluated their models using external data.

CONCLUSIONS

Seven popPK studies of IgG were found and discussed, with only weight being a significant covariate across all studies. Future studies linking pharmacokinetics with pharmacodynamics in PID and other patient populations are required.

Association of Rituximab Use With Adverse Events in Children, Adolescents, and Young Adults

IMPORTANCE

Rituximab is among the most frequently used immunotherapies in pediatrics. Few studies have reported long-term adverse events associated with its use for children.

OBJECTIVE

To describe the use of rituximab and to assess whether its use is associated with short- or long-term adverse events, infections, or time to immune reconstitution in a diverse group of young people.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 468 patients aged younger than 21 years who received rituximab for diverse indications between October 1, 2010, and December 31, 2017, at Texas Children's Hospital, a large pediatric referral hospital. Patterns of adverse events, infections, and immune recovery are described. Data analyses were conducted from December 2019 to June 2020.

EXPOSURE

One or more doses of rituximab.

MAIN OUTCOMES AND MEASURES

Adverse drug events (eg, anaphylaxis), incidence of mild and severe infections, and time to recovery of B lymphocyte subset counts and immunoglobulin levels. Survival models and logistic regression analyses and were used to identify associated risk factors of infectious and noninfectious adverse drug events.

RESULTS

We identified 468 patients receiving at least 1 dose of rituximab. The total follow-up time was 11 713 person-months. Of the 468 patients, 293 (62.6%) were female, the median (interquartile range) age at receipt of dose was 14.3 (9.9-16.8) years, and 209 (44.7%) were self-reported White Hispanic. Adverse events associated with rituximab infusion occurred in 72 patients (15.4%), and anaphylaxis occurred in 17 patients (3.6%). Long-term adverse events, such as prolonged neutropenia and leukoencephalopathy, were absent. Infections occurred in 224 patients (47.9%); 84 patients (17.9%) had severe infections, and 3 patients (0.6%) had lethal infections. Concurrent use of intravenous chemotherapy, treatment of systemic lupus erythematosus, neutropenia, and use of intravenous immunoglobulin were associated with increased risk of infection. Among 135 patients (28.8%) followed up to B cell count recovery, CD19+ or CD20+ cell numbers normalized in a median of 9.0 months (interquartile range, 5.9-14.4 months) following rituximab use; 48 of 95 patients (51%) evaluated beyond a year had low-for-age B cell counts. Recovery of CD27+ memory B cell number occurred in a median of 15.7 months (interquartile range, 6.0-22.7 months). Among patients with normal baseline values, low immunoglobulin G (IgG) levels developed in 67 of 289 patients (23.2%) and low IgM levels in 118 of 255 patients (40.8%); of these patients evaluated beyond 12 months from rituximab, 16 of 117 (13.7%) had persistently low IgG and 37 (33.9%) of 109 had persistently low IgM.

CONCLUSIONS AND RELEVANCE

Rituximab is well tolerated among young people and is associated with few serious adverse events, but infections are common, corresponding to a prolonged period of B cell count recovery often lasting for longer than a year. Further examination of strategies to prevent infections following rituximab should be pursued.

Population pharmacokinetic modelling of intravenous immunoglobulin in patients with predominantly antibody deficiencies

AIMS

There is considerable interpatient variability in the pharmacokinetics (PK) of intravenous immunoglobulin G (IVIG), causing difficulty in optimizing individual dosage regimen. This study aims to estimate the population PK parameters of IVIG and to investigate the impact of genetic polymorphism of the FcRn gene and clinical variability on the PK of IVIG in patients with predominantly antibody deficiencies.

METHODS

Patients were recruited from four hospitals. Clinical data were recorded and blood samples were taken for PK and genetic studies. Population PK parameters were estimated by nonlinear mixed-effects modelling in Monolix®. Models were evaluated using the difference in objective function value, goodness-of-fit plots, visual predictive check and bootstrap analysis. Monte Carlo simulation was conducted to evaluate different dosing regimens for IVIG.

RESULTS

A total of 30 blood samples were analysed from 10 patients. The immunoglobulin G concentration data were best described by a one-compartment model with linear elimination. The final model included both volume of distribution (Vd) and clearance (CL) based on patient's individual weight. Goodness-of-fit plots indicated that the model fit the data adequately, with minor model mis-specification. Genetic polymorphism of the FcRn gene and the presence of bronchiectasis did not affect the PK of IVIG. Simulation showed that 3-4-weekly dosing intervals were sufficient to maintain IgG levels of 5 g L^-1 , with more frequent intervals needed to achieve higher trough levels.

CONCLUSIONS

Body weight significantly affects the PK parameters of IVIG. Genetic and other clinical factors investigated did not affect the disposition of IVIG.

Efficacy and safety of human intravenous immunoglobulin 5% (Ig VENA) in pediatric patients affected by primary immunodeficiency

Patients affected by primary immunodeficiencies are characterized for high susceptibility for severe infections. Our data demonstrate Kedrion 5% intravenous immunoglobulin G (IVIg) treatment effective and safe as replacement therapy for children and adolescents affected by primary immunodeficiency. The particularities of our study are the selection of a long period of follow-up (71 patient-years of follow-up), and to the best of our knowledge, our study is one of few that assesses the safety and efficacy of intravenous immunoglobulin treatment of primary immunodeficiency specifically in a pediatric population.

A Systematic Review and Meta-regression Analysis on the Impact of Increasing IgG Trough Level on Infection Rates in Primary Immunodeficiency Patients on Intravenous IgG Therapy

PURPOSE

We conducted a systematic review and meta-regression analysis to evaluate the impact of increasing immunoglobulin G (IgG) trough levels on the clinical outcomes in patients with PID receiving intravenous immunoglobulin G (IVIG) treatment.

METHODS

Systematic search was conducted in PubMed and Cochrane. Other relevant articles were searched by reviewing the references of the reviewed article. All clinical trials with documented IgG trough levels and clinical outcome of interest in patients receiving IVIG treatment were eligible to be included in this review. Meta-regression analysis was conducted using Comprehensive Meta-analysis Software. Additional sensitivity analyses were undertaken to evaluate the robustness of the overall results.

RESULTS

Twenty-eight clinical studies with 1218 patients reported from year 2001 to 2018 were included. The mean IVIG dose used ranges from 387 to 560 mg/kg every 3 to 4 weekly, and mean IgG trough obtained ranges from 660 to 1280 mg/dL. Random-effects meta-regression slope shows that IgG trough level increases significantly by 73 mg/dL with every increase of 100 mg/kg dose of IVIG (p < 0.05). Overall infection rates reduced significantly by 13% with every increment of 100 mg/dL of IgG trough up to 960 mg/dL (p < 0.05).

CONCLUSION

This meta-analysis concludes that titrating the IgG trough levels up to 960 mg/dL progressively reduces the rate of infections, and there is less additional benefit beyond that. Further studies to validate this result are required before it can be used in clinical practice.