Pharmacokinetics of a new 10% intravenous immunoglobulin in patients receiving replacement therapy for primary immunodeficiency

Falsely abnormal serum protein electrophoresis after administration of intravenous immunoglobulins (IVIG): A retrospective cohort study

Intravenous immunoglobulin (IVIG) therapy, used in several neurologic, hematologic, immunologic and dermatologic conditions, is known to interfere with the results of some serum laboratory tests. We analyzed the potential interference of IVIG on serum protein electrophoresis (SPEP) by reviewing more than a decade of SPEP studies performed by the clinical immunology laboratory of the Johns Hopkins Hospital. Of the total 100,350 SPEP performed between January 1, 2013 and December 31, 2023, 395 contained the keyword IVIG in the pathologist report, contributed by 348 patients confirmed to have received IVIG by chart review. Of the 348 patients, 20 (6 %) had a M-spike on SPEP suggestive of monoclonal gammopathy, while 328 (94 %) did not have it. Of the 20 patients, 14 received IVIG within 30 days from the SPEP collection date, while 6 received beyond 30 days. Serum immunofixation electrophoresis (SIFE) and clinical follow up showed no evidence of monoclonal gammopathy in 5 of the 14 patients. Overall, this 11-year retrospective cohort study showed that 5 of 348 (1.4 %) patients treated with IVIG and tested by SPEP had a false M-spike, that is a spike not confirmed to be caused by a monoclonal gammopathy by subsequent studies. Although small, the false positive rate of 1.4 % suggests that integrating knowledge of recent IVIG administration into the pathologist report would reduce SPEP misdiagnosis.

Passive transfer of alloantibodies through breast milk as a mediator of hemolytic anemia

BACKGROUND

Hemolytic disease of the fetus and newborn (HDFN) is characterized by destruction of fetal/neonatal red blood cells (RBCs) secondary to maternally derived antibodies, which are typically thought to be passively acquired via placental transfer. Few cases have examined the possibility of HDFN mediated by maternal antibodies passively transferred via breast milk.

METHODS

We describe two cases of persistent HDFN in infants potentially mediated by passively acquired antibodies via maternal breast milk. We discuss supporting and refuting evidence that may account for this possibility and describe testing methodology illustrating how maternal alloantibodies can be detected in breast milk.

RESULTS

In both cases, anti-D antibodies were detected in maternal breast milk. One patient experienced a significant decrease in anti-D plasma titer from 64 to 4 dilutions following 2 weeks of breastfeeding cessation. The other patient experienced a resolution of anemia without breastfeeding cessation.

CONCLUSION

There is a paucity of data regarding the lifespan of passively acquired RBC antibodies in neonatal circulation, with significant variation noted between passively acquired IgG based on studies utilizing intravenous immunoglobulin compared to studies of maternally-acquired antiviral IgG antibodies. While our data do not definitively implicate passive transfer of alloantibodies in breast milk as a mediator of HDFN, they do illustrate the need for further investigation into the mechanisms and kinetics of passively acquired antibodies in neonatal circulation.

Presence of antibodies against HLA class I and class II molecules in children before and after allo-HSCT. Alloantibodies before and after HSCT

A severe complication of allogeneic hematopoietic stem cell transplantation (HSCT) is graft failure (GF). Among others, donor-specific anti-HLA antibodies (DSA) are associated with graft rejection after allogeneic or haploidentical transplantation in adults. Knowledge of DSA and pediatric recipients is limited. Hence, we aimed to generate more information about the presence of DSA (pre- and post-HSCT) and the clinical outcomes (graft rejection and poor function) in children. We identified DSA in 27% of the patients. We observed a higher frequency (50%) of DSA-bearing patients with a benign disease diagnosis than those diagnosed with leukemia (16.66%). We observed graft rejection in one patient (with DSA against two alleles of HLA class I molecules) and poor function in three recipients during the first 30 days after HSCT in the absence of DSA. The presence of donor and nondonor HLA-specific antibodies decreased substantially after transplantation. After the transplant, we identified two patients with DSA specific for HLA class I molecules (independent of clinical relevance), and four recipients showed PGF in the absence of DSA. We were unable to establish any association between the presence of DSA and a clinical outcome: graft failure or prevalence of viral infection.

Temporal outcomes after rituximab therapy for pemphigus vulgaris

Pemphigus vulgaris is an autoimmune blistering disease characterized by autoantibodies that target desmoglein adhesion proteins. Rituximab and corticosteroids are FDA-approved therapies for pemphigus vulgaris. As newer treatments for pemphigus enter clinical trials, analysis of clinical and serologic outcomes after rituximab therapy as a function of time is essential to guide clinical trial design. Here, we report detailed temporal and serological outcomes of rituximab treatment of pemphigus vulgaris. The maximal prevalence of complete remission off oral systemic therapy after a single cycle of rituximab was 32.4% at 12 months, or 43.1% by 36 months including additional rituximab cycles. Using receiver operating characteristic curves to develop prediction models for complete remission after a single cycle of rituximab, >90.7% reduction in average desmoglein 3 ELISA titers from baseline to months 3-9 was 94% sensitive, and an average absolute titer ≤130 RU/mL between months 3-9 was 96% specific, for achievement of complete remission off oral systemic therapy. All patients with negative titers at 6-9 months ultimately achieved complete remission off oral systemic therapy. This dataset of clinical and serological outcomes for pemphigus vulgaris patients after rituximab therapy will facilitate clinical trial planning and also guide clinician and patient expectations after rituximab therapy.

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.

Importance of immunoglobulin therapy for COVID-19 patients with lymphocytopenia

BACKGROUND

The global coronavirus disease 2019 (COVID-19) was announced as pandemic by the World Health Organization (WHO). With the increased number of infected and dead victims daily all over the world, it becomes necessary to stop or overcome its rapid spread.Main bodyAlthough the production of vaccine or even specified effective anti-virus may take about six months to a year, intravenous immunoglobulin (IVIg) may be clinically used as a safe treatment to save and improve the quality of life of patients with a variety of immunodeficiency diseases such as lymphocytopenia, which is a common clinical feature in COVID-19.

CONCLUSION

Through the current review, it was concluded that this passive immunization may promote the immunity to better fight against the virus, so the survival of the patients could be kept longer. The efficacy of immunotherapy with IVIg would be greater if the immune IgG antibodies were collected from convalescent plasma therapy.

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.

Efficacy and Safety of Revaccination against Tetanus, Diphtheria, Haemophilus influenzae Type b and Hepatitis B Virus in a Prospective Cohort of Adult Recipients of Allogeneic Hematopoietic Stem Cell Transplantation

Data on immunogenicity and safety of the recommended revaccination schedule against diphtheria, tetanus, poliomyelitis, pertussis, Haemophilus influenzae type b (Hib), and hepatitis B in adult allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients are limited. This prospective single-center cohort study (April 2014 to March 2018) included adult allo-HSCT recipients referred to a dedicated vaccinology consultation and vaccinated with the pediatric combined diphtheria, tetanus, acellular pertussis, hepatitis B virus, inactivated poliovirus, and Haemophilus influenzae type b (DTaP(±HB)-IPV-Hib) vaccine (3 doses 1 month apart, booster dose 1 year later). The proportion of responders to tetanus, diphtheria, Hib, and hepatitis B vaccine and geometric mean concentrations (GMCs) of antibodies were assessed before and up to 24 months after vaccination. A total of 106 patients were vaccinated at a median (interquartile range) time of 12.4 (10 to 18.4) months post-transplant. At 5.3 (4.8 to 6.6) and 23.1 (21.1 to 25.1) months after vaccine initiation, high and sustained rates of protective antibody titers were achieved for tetanus (97.8% [95% confidence interval (95% CI), 92.4% to 99.7%], n = 91/93 and 100% [95% CI, 92% to 100%], n = 44/44), diphtheria (94.6% [95% CI, 87.9% to 98.2%], n = 88/93 and 90.9% [95% CI, 78.3% to 97.5%], n = 40/44), Hib (96.6% [95% CI, 90.4% to 99.3%], n = 85/88 and 93% [95% CI, 80.9% to 98.5%], n = 40/43), and hepatitis B (83.5% [95% CI, 73.5% to 90.9%], n = 66/79 and 81.1% [95% CI, 64.8% to 92%], n = 30/37). Underlying disease, stem cell source, chronic graft-versus-host-disease, and extracorporeal photopheresis differentially influenced GMCs of tetanus, diphtheria, and hepatitis B antibodies after 3 doses but not in the long term (24 months). Six (5.7%) patients experienced mild side effects. The pediatric DTaP(±HB)-IPV-Hib vaccine was safe and effective in eliciting a sustained protective humoral response in adult allo-HSCT recipients. Hepatitis B revaccination might be optimized by using higher antigen doses.

Sagacity in antibody humanization for therapeutics, diagnostics and research purposes: considerations of antibody elements and their roles

The humanization of antibodies for therapeutics is a critical process that can determine the success of antibody drug development. However, the science underpinning this process remains elusive with different laboratories having very different methods. Well-funded laboratories can afford automated high-throughput screening methods to derive their best binder utilizing a very expensive initial set of equipment affordable only to a few. Often within these high-throughput processes, only standard key parameters, such as production, binding and aggregation are analyzed. Given the lack of suitable animal models, it is only at clinical trials that immunogenicity and allergy adverse effects are detected through anti-human antibodies as per FDA guidelines. While some occurrences that slip through can be mitigated by additional desensitization protocols, such adverse reactions to grafted humanized antibodies can be prevented at the humanization step. Considerations such as better antibody localization, avoidance of unspecific interactions to superantigens and the tailoring of antibody dependent triggering of immune responses, the antibody persistence on cells, can all be preemptively considered through a holistic sagacious approach, allowing for better outcomes in therapy and for research and diagnostic purposes.

Pharmacometric Analysis of IgPro10 in Japanese and Non-Japanese Patients With Primary Immunodeficiency

PURPOSE

Immunoglobulin (Ig) G replacement therapy, administered intravenously (IVIG) or subcutaneously (SCIG), is the standard treatment in patients with primary immunodeficiencies (PID). We aimed to characterize the pharmacokinetic (PK) characteristics of serum IgG following administration of IgPro10 every 3 or 4 weeks in Japanese patients with PID, and compare with PK in non-Japanese patients. A previously developed population PK (PPK) model was validated, and predicted parameters were compared with the results from the clinical study.

METHODS

The previously developed PPK model, containing IgG concentration data from 5 non-Japanese studies, was supplemented with data from 3 Japanese studies of IgPro10 or IgPro20 to compare the IgG PK parameters between Japanese and non-Japanese patients. The model was externally validated by simulating IgG concentration-time profiles in Japanese patients to predict serum IgG PK characteristics and to compare them with observed Japanese PK data from Study IgPro10_3004.

FINDINGS

The analysis included 4502 serum IgG concentration values (from 34 Japanese and 168 non-Japanese patients). PPK estimates from the current analysis demonstrated a clearance (CL) of 0.139 L/d, central volume (V2) of 4.01 L, inter-compartmental clearance (Q) of 0.30 L/d, and peripheral volume of 3.51 L. These results were consistent with those from the previously published PPK model, with similar bootstrap means and 95% CIs. Goodness-of-fit criteria indicated that the final PPK model was consistent with observed data, with no systemic bias in model prediction. Prediction-corrected visual predictive checks confirmed a good description of data on both SCIG and IVIG. PK parameters were equivalent between Japanese and non-Japanese patients. Body weight was determined to be a significant covariate on both CL and V2. Simulated and observed AUC and maximum and minimum serum IgG concentrations were similar, with 90% CIs overlapping between simulated and observed IgG concentrations in Japanese patients.

IMPLICATIONS

PK parameter estimates of serum IgG were similar between Japanese and non-Japanese patients with PID. The PPK model, updated with Japanese data, was consistent with the previously published PPK model and could accurately predict both individual and population serum IgG concentration-time profiles following IgPro10 IV infusions every 3 or 4 weeks. EudraCT identifier: 2016-001631-12.

Pharmacokinetic properties of Privigen® in Japanese patients with primary immunodeficiency

This prospective, Phase 3, open-label, study (EudraCT: 2016-001631-12) evaluated pharmacokinetic (PK) characteristics of 3-/4-weekly Privigen^® (IgPro10, CSL Behring, King of Prussia, PA, USA) in Japanese patients with PID. PK parameters including serum trough immunoglobulin (IgG) level before next infusion during the wash-in/wash-out phase (C_trough), area under the concentration-time curve from time point zero to the last time point with quantifiable concentration (AUC_0-last), dose-adjusted AUC_0-last (dAUC), lowest and highest observed IgG levels (C_min, C_max), time to reach C_max (T_max), and total clearance (CL) were analyzed for both regimens of Privigen^® (dose: 138-554 mg/kg body weight). Ten patients were included in this analysis (3-/4-weekly: n = 2/n = 8). C_trough levels achieved ranged 7.96-10.05 g/L. C_max was observed approximately 1 h after the start of the infusion in both regimens. Mean (SD [not applicable for 3-weekly data]) PK parameters: C_max, 16.60 and 14.20 (5.53) g/L; C_min, 10.60 and 8.53 (3.89) g/L; AUC_0-last, 5971 and 6591 (2633) g*h/L; dAUC, 0.41 and 0.46 (0.19) g*h/L/mg; CL, 2.53 and 2.53 (1.00) mL/h and median T_max was 1.19 and 1.14 h, for 3-/4-weekly dosing regimens, respectively. Privigen^® PK characteristics in Japanese patients were similar between dosing regimens and to previously-reported results in non-Japanese patients with PID.

Targeted Therapies for Autoimmune Bullous Diseases: Current Status

Autoimmune bullous skin disorders are rare but meaningful chronic inflammatory diseases, many of which had a poor or devastating prognosis prior to the advent of immunosuppressive drugs such as systemic corticosteroids, which down-regulate the immune pathogenesis in these disorders. Glucocorticoids and adjuvant immunosuppressive drugs have been of major benefit for the fast control of most of these disorders, but their long-term use is limited by major side effects such as blood cytopenia, osteoporosis, diabetes mellitus, hypertension, and gastrointestinal ulcers. In recent years, major efforts were made to identify key elements in the pathogenesis of autoimmune bullous disorders, leading to the identification of their autoantigens, which are mainly located in desmosomes (pemphigus) and the basement membrane zone (pemphigoids). In the majority of cases, immunoglobulin G, and to a lesser extent, immunoglobulin A autoantibodies directed against distinct cutaneous adhesion molecules are directly responsible for the loss of cell-cell and cell-basement membrane adhesion, which is clinically related to the formation of blisters and/or erosions of the skin and mucous membranes. We describe and discuss novel therapeutic strategies that directly interfere with the production and regulation of pathogenic autoantibodies (rituximab), their catabolism (intravenous immunoglobulins), and their presence in the circulation and extravascular tissues such as the skin (immunoadsorption), leading to a significant amelioration of disease. Moreover, we show that these novel therapies have pleiotropic effects on various proinflammatory cells and cytokines. Recent studies in bullous pemphigoid suggest that targeting of immunoglobulin E autoantibodies (omalizumab) may be also beneficial. In summary, the introduction of targeted therapies in pemphigus and pemphigoid holds major promise because of the high efficacy and fewer side effects compared with conventional global immunosuppressive therapy.

Intravenous immunoglobulin 10% in children with primary immunodeficiency diseases

AIM

To assess the safety and efficacy of an intravenous immunoglobulin (IVIG) 10% preparation (Panzyga^®; Octapharma AG, Lachen, Switzerland) in predominantly antibody-deficient children with primary immunodeficiency disease.

METHODS

Data from two prospective, open-label and noncontrolled multicenter Phase III studies of IVIG 10% that included 25 patients <16 years of age were analyzed for efficacy, pharmacokinetics and safety.

RESULTS

The rate of serious bacterial infections was 0.04/patient-year. A maximal infusion rate of 0.14 ml/kg/min was achieved in 82% of pediatric patients (n = 9). Infusions of immunoglobulin G trough levels between infusions remained ≥5-6 g/l; median half-life was 32.79-36.62 days. Abdominal pain, headache and chills were the most common treatment-related adverse events.

CONCLUSION

IVIG 10% is safe and effective for the treatment of predominantly antibody-deficient children.

Pharmacokinetics of a novel human intravenous immunoglobulin 10% in patients with primary immunodeficiency diseases: Analysis of a phase III, multicentre, prospective, open-label study

Intravenous immunoglobulin (IVIG) therapy is commonly used to treat patients with primary antibody deficiency. This prospective, open-label, non-randomised, multicentre, phase III trial investigated the pharmacokinetics of a new 10% liquid IVIG product (panzyga®; Octapharma) in 51 patients aged 2-75 years with common variable immunodeficiency (n = 43) or X-linked agammaglobulinaemia (n = 8). Patients were treated with IVIG 10% every 3 (n = 21) or 4 weeks (n = 30) at a dose of 200-800 mg/kg for 12 months. Total immunoglobulin G (IgG) and subclass concentrations approximately doubled from pre- to 15 min post-infusion. The maximum concentration of total IgG (mean ± SD) was 21.82 ± 5.83 g/L in patients treated 3-weekly and 17.42 ± 3.34 g/L in patients treated 4-weekly. Median trough IgG concentrations were nearly constant over the course of the study, remaining between 11.0 and 12.2 g/L for patients on the 3-week schedule and between 8.10 and 8.65 g/L for patients on the 4-week schedule. The median terminal half-life of total IgG was 36.1 (range 18.5-65.9) days, with generally similar values for the IgG subclasses (26.7-38.0 days). Median half-lives for specific antibodies ranged between 21.3 and 51.2 days for anti-cytomegalovirus, anti-Haemophilus influenzae, anti-measles, anti-tetanus toxoid, anti-varicella zoster virus antibodies, and anti-Streptococcus pneumoniae subtype antibodies. Overall, IVIG 10% demonstrated pharmacokinetic properties similar to those of other commercial IVIG 10% preparations and 3- or 4-weekly administration achieved sufficient concentrations of IgG, IgG subclasses, and specific antibodies, exceeding the recommended level needed to effectively prevent serious bacterial infections.

A Multicentre Study on the Efficacy, Safety and Pharmacokinetics of IqYmune®, a Highly Purified 10% Liquid Intravenous Immunoglobulin, in Patients with Primary Immune Deficiency

This multicentre, open-label, prospective, single-arm study was designed to evaluate the efficacy, pharmacokinetics, and safety of IqYmune®, a highly purified 10% polyvalent immunoglobulin preparation for intravenous administration in patients with primary immunodeficiency. IqYmune® was administered to 62 patients (aged 2–61 years) with X-linked agammaglobulinemia or common variable immune deficiency at a dose from 0.22 to 0.97 g/kg every 3 to 4 weeks for 12 months with an infusion rate up to 8 mL/kg/h. A pharmacokinetic study was performed at steady state between the 8th and the 9th infusion. A single case of serious bacterial infection was observed, leading to an annualized rate of serious bacterial infections/patient (primary endpoint) of 0.017 (98% CI: 0.000, 0.115). Overall, 228 infections were reported, most frequently bronchitis, chronic sinusitis, nasopharyngitis and upper respiratory tract infection. The mean annualized rate of infections was 3.79/patient. A lower risk of infections was associated with an IgG trough level > 8 g/L (p = 0.01). The mean annualized durations of absence from work or school and of hospitalization due to infections were 1.01 and 0.89 days/patient, respectively. The mean serum IgG trough level before the 6th infusion was 7.73 g/L after a mean dose of IqYmune® of 0.57 g/kg. The pharmacokinetic profile of IqYmune® was consistent with that of other intravenous immunoglobulins. Overall, 15.5% of infusions were associated with an adverse event occurring within 72 h post infusion. Headache was the most common adverse event. In conclusion, IqYmune® was shown to be effective and well tolerated in patients with primary immunodeficiency.

Impact of Parvovirus B19 Viremia in Liver Transplanted Children on Anemia: A Retrospective Study

Acute parvovirus B19 (B19V) infection in immunocompromised patients may lead to severe anemia. However, in adult transplant recipients, B19V reactivations without anemia and low-level viremia are common. The impact of B19V in pediatric transplant patients, with high risk of primary infection, is investigated here. In a six-month period, 159 blood samples of 54 pediatric liver transplant recipients were tested for B19V DNA by quantitative real-time PCR. Viremia was correlated with anemia and immunosuppression and compared with rates in adult transplant recipients. B19V DNA was detected in 5/54 patients. Primary B19V infections were observed in four patients prior to and in one patient after transplantation. Rates of viremia were significantly higher in pediatric recipients than in adults. Prolonged virus shedding after primary infection prior to transplantation accounts for most viremic cases. Anemia was significantly more frequent in samples from viremic patients, but remained mild. In 15% of anemic samples, B19V DNA was detected. Therefore, in anemic pediatric transplant recipients, diagnostics for B19V seem reasonable.

Pharmacokinetics and Pharmacodynamics of Intravenous Immunoglobulin G Maintenance Therapy in Chronic Immune-mediated Neuropathies

The regimen for IVIg maintenance treatment varies considerably between patients with chronic immune-mediated neuropathies. Although it is widely recognized that treatment regimens should be improved, detailed pharmacokinetics (PK) of IVIg have not yet been established. We aimed to determine the PK of IVIg maintenance treatment in patients with clinically stable, treatment-dependent, chronic immune-mediated neuropathy. Patients received a median IVIg dose of 30 g (range, 15-70 g) every 14 days (range, 7-28 days) resulting in high IgG peak levels (median, 25.9 g/L; range, 16.7-41.0 g/L) and trough levels (median, 16.1 g/L; range, 9.7-23.6 g/L). IgG PK parameters, including half-life (median, 23.1 days; range, 11-60 days), were constant during subsequent courses in the same patients, but varied considerably between patients. The IgG levels at 1 week after infusion correlated with grip strength. These results provide insight into the PK of IVIg maintenance treatment in patients with chronic immune-mediated neuropathies.

Hypogammaglobulinemia in infants receiving chronic peritoneal dialysis

BACKGROUND

Peritonitis is a severe complication of chronic peritoneal dialysis (CPD) in infants. Few studies have been conducted to evaluate the relationship between hypogammaglobulinemia and peritonitis risk, and the potential benefit of intravenous immunoglobulins (IVIG) therapy in infants receiving CPD.

METHODS

Patients aged 0-12 months at initiation of CPD between 1985 and 2012 were eligible for inclusion in this retrospective study. Data collected from the start of CPD up to 2 years post-dialysis initiation included patient demographics, dialysis characteristics, serum immunoglobulin (IgG) levels, IVIG administration history, infectious complications and outcomes. Cox regression analysis and linear mixed model analysis were used for statistical analysis.

RESULTS

Twenty-six consecutive patients were included in the study. Annualized peritonitis rates for infants aged 0-30 days (≤1-month age group; n = 16; 320.3 patient-months) and 31-365 days (>1-12-month age group; n = 10; 163.3 patient-months) at dialysis initiation were 0.27 (1 episode per 45.8 patient-months) and 0.15 (one episode per 81.7 patient-months), respectively. Seventy-six percent of the serum IgG levels were >1 standard deviation below the age-appropriate mean levels, and these did not differ in those who developed peritonitis versus those who did not (p = 0.39). Serum IgG levels were significantly lower in patients on CPD with oligoanuria than in non-oliguric patients (p = 0.04) and in patients on CPD for >90 days as compared to those who had received CPD for <90 days (p = 0.018). IVIG therapy was provided to 20 patients with hypogammaglobulinemia; this high prevalence of IVIG usage precluded any drawing of conclusion on the potential role of IVIG in the prevention of peritonitis.

CONCLUSIONS

Hypogammaglobulinemia is a frequent complication of CPD during infancy. In our experience, it was not associated with an increased risk for peritonitis.

Recombinant human hyaluronidase facilitated subcutaneous immunoglobulin treatment in pediatric patients with primary immunodeficiencies: long-term efficacy, safety and tolerability

AIM

To assess the long-term efficacy, safety and tolerability of recombinant human hyaluronidase-facilitated subcutaneous infusion of immunoglobulin (Ig) (fSCIG; HYQVIA(®); IGHy) in children aged <18 years.

PATIENTS & METHODS

Patients with primary immunodeficiency diseases were included in the studies. IGHy was administered every 3 or 4 weeks.

RESULTS

Validated acute serious bacterial infections were reported at 0.08/patient-year (four pneumonia episodes in three patients). No serious adverse drug reaction (ADR) was reported, and rates of local and systemic ADRs were low (0.09/infusion and 0.1/infusion). Infection rates were low (3.02/patient-year) with sustained Ig trough levels (median: 1009 mg/dl). Of 674 IGHy infusions, 97.2% required no change of administration due to ADR, in most (82.5%) with one infusion site. No patient developed neutralizing anti-rHuPH20 antibodies. Postpivotal study, 100% of patients aged <14 years or their caregivers and 85.7% of patients aged 14 to <18 years expressed preference for IGHy compared with Ig administered intravenously or Ig administered subcutaneously.

CONCLUSION

These studies, with the longest (maximum: 3.3 years) duration of any reported Ig replacement trials in children with primary immunodeficiency diseases, showed low infection, local and systemic reaction rates along with well-tolerated infusions given in a single site.

Subcutaneous immunoglobulins in the treatment of chronic immune-mediated neuropathies

Intravenous immunoglobulins represent an established therapy for the treatment of chronic immune-mediated neuropathies, specifically chronic inflammatory demyelinating polyradiculoneuropathies (CIDPs) as well as multifocal motor neuropathies (MMNs). For the treatment of antibody deficiency syndromes, subcutaneous immunoglobulins (SCIgs) have represented a mainstay for decades. An emerging body of evidence suggests that SCIg might also exhibit clinical efficacy in CIDP and MMN. This article reviews the current evidence for clinical effectiveness, as well as safety of SCIg for the treatment of immune-mediated neuropathies, and addresses remaining open questions in this context. We conclude that despite the need for controlled long-term studies to demonstrate long-term efficacy of SCIg in immune-mediated neuropathies, SCIg may already represent a potential therapeutic alternative for selected patients.

The Production Processes and Biological Effects of Intravenous Immunoglobulin

Immunoglobulin is a highly diverse autologous molecule able to influence immunity in different physiological and diseased situations. Its effect may be visible both in terms of development and function of B and T lymphocytes. Polyclonal immunoglobulin may be used as therapy in many diseases in different circumstances such as primary and secondary hypogammaglobulinemia, recurrent infections, polyneuropathies, cancer, after allogeneic transplantation in the presence of infections and/or GVHD. However, recent studies have broadened the possible uses of polyclonal immunoglobulin showing that it can stimulate certain sub-populations of T cells with effects on T cell proliferation, survival and function in situations of lymphopenia. These results present a novel and considerable impact of intravenous immunoglobulin (IVIg) treatment in situations of severe lymphopenia, a situation that can occur in cancer patients after chemo and radiotherapy treatments. In this review paper the established and experimental role of polyclonal immunoglobulin will be presented and discussed as well as the manufacturing processes involved in their production.

Current treatment options with immunoglobulin G for the individualization of care in patients with primary immunodeficiency disease

Primary antibody deficiencies require lifelong replacement therapy with immunoglobulin (Ig)G to reduce the incidence and severity of infections. Both subcutaneous and intravenous routes of administering IgG can be effective and well tolerated. Treatment regimens can be individualized to provide optimal medical and quality-of-life outcomes in infants, children, adults and elderly people. Frequency, dose, route of administration, home or infusion-centre administration, and the use of self- or health-professional-administered infusion can be tailored to suit individual patient needs and circumstances. Patient education is needed to understand the disease and the importance of continuous therapy. Both the subcutaneous and intravenous routes have advantages and disadvantages, which should be considered in selecting each patient's treatment regimen. The subcutaneous route is attractive to many patients because of a reduced incidence of systemic adverse events, flexibility in scheduling and its comparative ease of administration, at home or in a clinic. Self-infusion regimens, however, require independence and self-reliance, good compliance on the part of the patient/parent and the confidence of the physician and the nurse. Intravenous administration in a clinic setting may be more appropriate in patients with reduced manual dexterity, reluctance to self-administer or a lack of self-reliance, and intravenous administration at home for those with good venous access who prefer less frequent treatments. Both therapy approaches have been demonstrated to provide protection from infections and improve health-related quality of life. Data supporting current options in IgG replacement are presented, and considerations in choosing between the two routes of therapy are discussed.

Is dosing of therapeutic immunoglobulins optimal? A review of a three-decade long debate in europe

The consumption of immunoglobulins (Ig) is increasing due to better recognition of antibody deficiencies, an aging population, and new indications. This review aims to examine the various dosing regimens and research developments in the established and in some of the relevant off-label indications in Europe. The background to the current regulatory settings in Europe is provided as a backdrop for the latest developments in primary and secondary immunodeficiencies and in immunomodulatory indications. In these heterogeneous areas, clinical trials encompassing different routes of administration, varying intervals, and infusion rates are paving the way toward more individualized therapy regimens. In primary antibody deficiencies, adjustments in dosing and intervals will depend on the clinical presentation, effective IgG trough levels and IgG metabolism. Ideally, individual pharmacokinetic profiles in conjunction with the clinical phenotype could lead to highly tailored treatment. In practice, incremental dosage increases are necessary to titrate the optimal dose for more severely ill patients. Higher intravenous doses in these patients also have beneficial immunomodulatory effects beyond mere IgG replacement. Better understanding of the pharmacokinetics of Ig therapy is leading to a move away from simplistic "per kg" dosing. Defective antibody production is common in many secondary immunodeficiencies irrespective of whether the causative factor was lymphoid malignancies (established indications), certain autoimmune disorders, immunosuppressive agents, or biologics. This antibody failure, as shown by test immunization, may be amenable to treatment with replacement Ig therapy. In certain immunomodulatory settings [e.g., idiopathic thrombocytopenic purpura (ITP)], selection of patients for Ig therapy may be enhanced by relevant biomarkers in order to exclude non-responders and thus obtain higher response rates. In this review, the developments in dosing of therapeutic immunoglobulins have been limited to high and some medium priority indications such as ITP, Kawasaki' disease, Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, myasthenia gravis, multifocal motor neuropathy, fetal alloimmune thrombocytopenia, fetal hemolytic anemia, and dermatological diseases.

Enhancing Patient Flexibility of Subcutaneous Immunoglobulin G Dosing: Pharmacokinetic Outcomes of Various Maintenance and Loading Regimens in the Treatment of Primary Immunodeficiency

Introduction

Standard treatment for patients with primary immunodeficiency (PID) is monthly intravenous immunoglobulin (IVIG), or weekly/biweekly subcutaneous immunoglobulin (SCIG) infusion. We used population pharmacokinetic modeling to predict immunoglobulin G (IgG) exposure following a broad range of SCIG dosing regimens for initiation and maintenance therapy in patients with PID.

Methods

Simulations of SCIG dosing were performed to predict IgG concentration–time profiles and exposure metrics [steady-state area under the IgG concentration–time curve (AUC), IgG peak concentration (C_max), and IgG trough concentration (C_min) ratios] for various infusion regimens.

Results

The equivalent of a weekly SCIG maintenance dose administered one, two, three, five, or seven times per week, or biweekly produced overlapping steady-state concentration–time profiles and similar AUC, C_max, and C_min values [95% confidence interval (CI) for ratios was 0.98–1.03, 0.95–1.09, and 0.92–1.08, respectively]. Administration every 3 or 4 weeks resulted in higher peaks and lower troughs; the 95% CI of the AUC, C_max, and C_min ratios was 0.97–1.04, 1.07–1.26, and 0.86–0.95, respectively. IgG levels >7 g/L were reached within 1 week using a loading dose regimen in which the weekly maintenance dose was administered five times in the first week of treatment. In patients with very low endogenous IgG levels, administering 1.5 times the weekly maintenance dose five times in the first week of treatment resulted in a similar response.

Conclusions

The same total weekly SCIG dose can be administered at different intervals, from daily to biweekly, with minimal impact on serum IgG levels. Several SCIG loading regimens rapidly achieve adequate serum IgG levels in treatment-naïve patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s13554-014-0018-0) contains supplementary material, which is available to authorized users.

Subcutaneous immunoglobulin therapy for inflammatory neuropathy: current evidence base and future prospects

Intravenous immunoglobulin therapy is of proven effect in chronic inflammatory neuropathies, including chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). In more recent years, there have been a number of anecdotal case reports and small series, followed by a few trials of variable design, of subcutaneous immunoglobulin therapy in these neuropathies. To date, limited evidence suggests that the subcutaneous route may be a more clinically effective, better-tolerated, at least cost-equivalent and a more patient-friendly option than the still more used intravenous alternative. Long-term efficacy is not as yet established in neuropathic indications by randomised controlled clinical trial evidence, and it is likely that the subcutaneous route may not be suitable in all cases with some hints to this effect appearing from the limited data available to date. Further studies are ongoing, including those of dose comparison, and more are likely to be planned in future. The literature on the use of subcutaneous immunoglobulin therapy in chronic inflammatory neuropathy is reviewed here. The current use in clinical practice, day-to-day benefits, including quality of life measures and health economics as published thus far, are evaluated. The limitations of this form of treatment in CIDP and MMN are also analysed in the light of current literature and taking into account the remaining unknowns. Future prospects and research with this mode of immunoglobulin therapy administration are discussed.

Development, manufacturing and characterization of a highly purified, liquid immunoglobulin g preparation from human plasma

BACKGROUND

The use of plasma-derived immunoglobulin G (IgG) is increasing, and the number of diseases, including immunodeficiencies, neurological diseases and autoimmune conditions, treated with intravenous IgG (IVIG) is expanding. Consequently, there is a great need for high-yield production processes for plasma-derived IgG. The aim of this work was to develop a high-yield process leading to a highly purified, liquid, ready-to-use IgG for intravenous use.

METHODS

Plasma from healthy, voluntary, non-remunerated donors was fractionated by ethanol precipitation. IgG was extracted from fraction II + III using a phosphate/acetate buffer, pH 4, and purified by chromatography.

RESULTS

Precipitation with 6% polyethylene glycol at pH 7 removed high molecular-weight contaminating proteins, aggregates and contaminating viruses. Ion exchange chromatography at pH 5.7 on serially connected anion and cation exchange columns allowed for elution of IgG from the cation exchange column in good yield and high purity. Further safety was achieved by solvent/detergent treatment and repeated ion exchange chromatography. The product consisted of essentially only IgG monomers and dimers, and had a high purity with very low levels of IgM and IgA.

CONCLUSION

A process providing highly purified IVIG in good yield was developed.

Pneumococcal antibody levels in children with PID receiving immunoglobulin

OBJECTIVES

Clinical data are lacking on optimal levels of specific antipneumococcal antibodies (PnPsAbs) in patients with primary immunodeficiency (PID) receiving intravenous immunoglobulin (IVIG) replacement. Objectives were to conduct a prospective multicenter study providing data on total immunoglobulin G (IgG) and peak/trough levels of PnPsAbs specifically targeting the 16 most prevalent pneumococcal serotypes in IVIG-treated children with PID; to compare trough PnPsAb levels with those measured in healthy adults and the IVIG product; and to evaluate PnPsAb protection correlates with thresholds based on World Health Organization.

METHODS

Patients received 7 consecutive IVIG infusions. Total IgG and PnPsAb levels were determined on plasma samples obtained before and after infusion.

RESULTS

Twenty-two children with PID were treated with IVIG (mean weekly dose: 0.10 g/kg). The mean trough and peak levels of total IgG were 7.77 and 13.93 g/L, respectively. Trough and peak geometric mean concentrations and distribution curves differed between serotypes and showed wide dispersion (0.17-7.96 µg/mL). In patients (89%-100%), antibodies against most serotypes reached trough levels ≥ 0.2 µg/mL, a threshold considered protective against invasive pneumococcal infection. For several serotypes, trough levels reached ≥ 1.0 to 1.3 µg/mL, the level found in adults. Trough geometric mean concentrations correlated well with the PnPsAb contents of the IVIG product.

CONCLUSIONS

In IVIG-treated children with PID, protective PnPsAb levels for most pathogenic serotypes were obtained. A correlation was observed between PnPsAb levels in patients and in the IVIG product. This offers the potential to improve infection prevention by adapting the IVIG product and dose according to epidemiology.

Does intravenous immunoglobulin therapy prolong immunodeficiency in transient hypogammaglobulinemia of infancy?

Transient hypogammaglobulinemia of infancy (THI) is characterized by recurrent infections and one or more reduced serum immunoglobulin levels. Typically, THI patients recover spontaneously, mostly within 30-40 months of age, but sometimes recovery may be delayed until 5-6 years of age. The use of intravenous immunoglobulin (IVIg) as an alternative to antibiotic prophylaxis remains contraversial also in symptomatic THI patients. In fact, some authors believe that IVIg therapy may cause a delay in the maturation of the humoral immune system because of the interference from passively transfered antibodies. The aim of this study was to investigate the effect of IVIg replacement on recovery from immunodeficiency in THI patients and determine new parameters in order to include these patients in IVIg therapy groups. In this retrospective study, 43 patients (65%) received IVIg replacement therapy while 23 patients (34.8%) showed spontaneous normalization without IVIg. The percentages of patients who had more than six times the number of febrile infections in a year decreased from 91% to 21% in the group receiving IVIg treatment. At admission, before being recruited to IVIg therapy, serum immunoglobulin G (IgG) levels and anti-hemophilus B (Hib) antibody titers were found to be significantly low in cases who were selected for IVIg replacement. The percentages of patients who did not have protective levels of anti-Hib, anti-rubella or anti-rubeola-IgG were also significantly high in IVIg cases. There was no statistically significant difference in the age at which IgG levels normalized between the IVIg and the non-IVIg group. Patients in the IVIg group and non-IVIg group reached normal IgG levels at the age of 42.9±22.0 and 40.7±19.8 months, respectively. In conclusion, IVIg infusions do not cause a delay in the maturation of the immune system in THI patients. Besides the well-established criteria, very low and non-protective specific antibody responses against previously applied vaccines are important factors to consider when selecting patients for IVIg therapy.

Pharmacokinetics of subcutaneous IgPro20 in patients with primary immunodeficiency

BACKGROUND AND OBJECTIVES

Immunoglobulin replacement is a standard therapy for patients with primary immunodeficiencies. Subcutaneous administration of immunoglobulin offers more constant IgG levels than intravenous administration and simplifies administration for some patients. Use of L-proline as an excipient contributes to the stability of highly concentrated IgG preparations. The aims of the present study were to evaluate the pharmacokinetics of IgPro20 (Hizentra®), a new 20% subcutaneous IgG solution, and compare the area under the serum concentration-time curve (AUC) with that of a similar intravenous 10% IgG solution (IgPro10; Privigen®). At the request of the US FDA, an algorithm for determining IgG trough level ratios (TLRs) was developed in order to provide physicians with a practical tool for monitoring doses during steady-state IgPro20 therapy.

METHODS

This was a prospective, open-label, multicentre, single-arm, phase III clinical trial conducted in the US. The study was performed in a primary-care setting. Eligible patients were males or females aged 6-75 years with a primary immunodeficiency (common variable immunodeficiency or X-linked agammaglobulinaemia) who had received regular treatment with IgPro10 for at least 3 months prior to entering this study and had achieved serum trough concentration (C(trough)) values ≥5 g/L. IgPro20 was administered subcutaneously once weekly at initial doses equivalent to 130% of patients' previous doses, based on the results obtained in a Vivaglobin® study and due to an FDA request. After run-in, each patient's dose was adjusted to achieve an AUC comparable to that achieved with IgPro10 administered intravenously.

RESULTS

Eighteen patients completed the study. Mean IgPro20 : IgPro10 dose ratio (dose adjustment coefficient) was 1.53 (range 1.26-1.87). The resulting mean AUCs were 105.6 g · day/L for IgPro20 versus 103.2 g · day/L for IgPro10 (geometric mean ratio 1.002; lower one-sided 95% confidence limit [CL] 0.951). Thus, the primary endpoint of the study was met, as this result exceeded the pre-specified criterion of the lower one-sided 95% CL of ≥0.8 for non-inferiority. At these AUCs, which were considered equivalent, the mean IgPro20 : IgPro10 TLR, determined by the developed algorithm, was 1.29 (range 1.18-1.73). Titres of specific antibodies tested were well above respective product specifications, suggesting that protection against infection would be effective.

CONCLUSION

Steady-state AUCs with subcutaneous IgPro20 and intravenous IgPro10 were equivalent. Mean dose adjustment coefficient and mean TLR can be used for initial dose conversion without risk of under-protection but vary too widely to be considered measures of equivalence. Trial registration number (clinicaltrials.gov): NCT00419341.

L-proline-stabilized human IgG: Privigen® 10% for intravenous use and Hizentra® 20% for subcutaneous use

Liquid IgG preparations are preferred over lyophilized preparations because reconstitution is not required. Formation of dimers and aggregates in liquid preparations increases adverse effects and limits the shelf life of most liquid IgG products. Improved understanding of the binding interactions in IgG dimers and aggregates led to the selection of L-proline at pH 4.8 as an excipient that would minimize their formation. CSL Behring has developed the L-proline-stabilized products Privigen®, a 10% IgG solution for intravenous use; and Hizentra®, a 20% solution for subcutaneous use. The former has the longest shelf life of any liquid IgG in the USA--36 months, and the latter is the most concentrated IgG available. These improvements, which translate into improved convenience for pharmacies and patients, were achieved with no compromise in safety, efficacy or tolerability of the products.

Relevant criteria for selecting an intravenous immunoglobulin preparation for clinical use

Over the past several decades, the use of intravenous human normal immunoglobulin (IVIg) products in a diverse range of immunodeficiency, inflammatory and infectious disorders has increased significantly. Newer manufacturing processes have increased the yield of intact IVIg molecules and have also improved the tolerability and safety of these products, including reducing the transmission risk of blood-borne diseases. While there are no appreciable differences between the numerous commercially available IVIg products in terms of efficacy, different manufacturing processes and the final composition of IVIg products have resulted in different safety and tolerability profiles. The tolerability profile of different IVIg products may be idiosyncratic for individual patients and may not be predictable, based on product characteristics. Consequently, patients receiving an IVIg product should be carefully monitored at initial exposure, and switching of products should be avoided. To achieve the best outcomes in patients requiring IVIg therapy, treatment should be tailored to the patient's needs. The risk/benefit profile of an IVIg in relation to patient risk factors and the underlying immune deficiency, or autoimmune or inflammatory disorder should be considered when deciding on the most appropriate therapy.

Long-lived plasma cells and memory B cells produce pathogenic anti-GAD65 autoantibodies in Stiff Person Syndrome

Stiff person syndrome (SPS) is a rare, neurological disorder characterized by sudden cramps and spasms. High titers of enzyme-inhibiting IgG autoantibodies against the 65 kD isoform of glutamic acid decarboxylase (GAD65) are a hallmark of SPS, implicating an autoimmune component in the pathology of the syndrome. Studying the B cell compartment and the anti-GAD65 B cell response in two monozygotic twins suffering from SPS, who were treated with the B cell-depleting monoclonal anti-CD20 antibody rituximab, we found that the humoral autoimmune response in SPS is composed of a rituximab-sensitive part that is rapidly cleared after treatment, and a rituximab-resistant component, which persists and acts as a reservoir for autoantibodies inhibiting GAD65 enzyme activity. Our data show that these potentially pathogenic anti-GAD65 autoantibodies are secreted by long-lived plasma cells, which may either be persistent or develop from rituximab-resistant memory B lymphocytes. Both subsets represent only a fraction of anti-GAD65 autoantibody secreting cells. Therefore, the identification and targeting of this compartment is a key factor for successful treatment planning of SPS and of similar autoimmune diseases.

Subcutaneous immunoglobulin: opportunities and outlook

Immunoglobulin (Ig) administration via the subcutaneous (s.c.) route has become increasingly popular in recent years. The method does not require venous access, is associated with few systemic side effects and has been reported to improve patients' quality of life. One current limitation to its use is the large volumes which need to be administered. Due to the inability of tissue to accept such large volumes, frequent administration at multiple sites is necessary. Most studies conducted to date have investigated the use of subcutaneous immunoglobulin (SCIg) in patients treated previously with the intravenous (i.v.) formulation. New data now support the use of s.c. administration in previously untreated patients with primary immunodeficiencies. SCIg treatment may further be beneficial in the treatment of autoimmune neurological conditions, such as multi-focal motor neuropathy; however, controlled trials directly comparing the s.c. and i.v. routes are still to be performed for this indication. New developments may further improve and facilitate the s.c. administration route. For example, hyaluronidase-facilitated administration increases the bioavailability of SCIg, and may allow for the administration of larger volumes at a single site. Alternatively, more concentrated formulations may reduce the volume required for administration, and a rapid-push technique may allow for shorter administration times. As these developments translate into clinical practice, more physicians and patients may choose the s.c. administration route in the future.