Adverse effects of intravenous immunoglobulin therapy

Good practice statements (GPS) for the clinical care of patients with thrombotic thrombocytopenic purpura

BACKGROUND

Despite advances in treatment options for thrombotic thrombocytopenic purpura (TTP), there are still limited high quality data to inform clinicians regarding its management.

METHODS

In June 2018, the ISTH formed a multidisciplinary guideline panel to issue recommendations about treatment of TTP. The panel discussed 12 treatment questions related to both immune-mediated TTP (iTTP) and hereditary/congenital TTP (cTTP). The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including evidence-to-decision frameworks, to appraise evidence and formulate recommendations.

RESULTS

The panel agreed on eleven recommendations based on evidence ranging from very low to moderate certainty. For first episode and relapses of acute iTTP, the panel made a strong recommendation for the addition of corticosteroids to therapeutic plasma exchange (TPE), and a conditional recommendation for addition of rituximab and caplacizumab. For asymptomatic iTTP with low ADAMTS13, the panel made a conditional recommendation for rituximab outside of pregnancy, and for prophylactic TPE during pregnancy. For asymptomatic cTTP, the panel made a strong recommendation for prophylactic plasma infusion during pregnancy, but a conditional recommendation for plasma infusion or a wait and watch approach outside of pregnancy.

CONCLUSIONS

The panel's recommendations are based on all the available evidence for the treatment effects of various approaches including suppressing inflammation, blocking platelet clumping, replacing the missing and/or inhibited ADAMTS13, and suppressing ADAMTS13 antibody production. There was insufficient evidence for further comparison of different treatment approaches, for which future high-quality studies in iTTP (e.g., rituximab, corticosteroids, recombinant ADAMTS13, and caplacizumab) and in cTTP (eg, recombinant ADAMTS13) are needed.

Multi-step conformational transitions in heat-treated protein therapeutics can be monitored in real time with temperature-controlled electrospray ionization mass spectrometry

Heat-induced conformational transitions are frequently used to probe the free energy landscapes of proteins. However, the extraction of information from thermal denaturation profiles pertaining to non-native protein conformations remains challenging due to their transient nature and significant conformational heterogeneity. Previously we developed a temperature-controlled electrospray ionization (ESI) source that allowed unfolding and association of biopolymers to be monitored by mass spectrometry (MS) in real time as a function of temperature. The scope of this technique is now extended to systems that undergo multi-step denaturation upon heat stress, as well as relatively small-scale conformational changes that are precursors to protein aggregation. The behavior of two therapeutic proteins (human antithrombin and an IgG1 monoclonal antibody) under heat-stress conditions is monitored in real time, providing evidence that relatively small-scale conformational changes in each system lead to protein oligomerization, followed by aggregation. Temperature-controlled ESI MS is particularly useful for the studies of heat-stressed multi-domain proteins such as IgG, where it allows distinct transitions to be observed. The ability of native temperature-controlled ESI MS to monitor both the conformational changes and oligomerization/degradation with high selectivity complements the classic calorimetric methods, lending itself as a powerful experimental tool for the thermostability studies of protein therapeutics.

The Effects of Light-Accelerated Degradation on the Aggregation of Marketed Therapeutic Monoclonal Antibodies Evaluated by Size-Exclusion Chromatography With Diode Array Detection

Research into the effects that exposure to light can have on therapeutic proteins is essential for ensuring the quality and safety of the medicines in which they are used. It is important to understand the effects of light on aggregation to help avoid undesirable colloidal instabilities, both in the original medicines and in the formats in which they are finally administered. In this study, 5 marketed therapeutic mAbs, namely bevacizumab, cetuximab, infliximab, rituximab, and trastuzumab, were investigated for this purpose. The medicines and 2 diluted preparations in 0.9 NaCl (2 mg/mL and 5 mg/mL)-commonly used in clinical practice-were subjected to controlled light-accelerated degradation. The formation of aggregates was monitored by size-exclusion chromatography. The results indicated that light induced protein aggregation. This process of protein damage was influenced above all by mAb concentration, although the particular characteristics of each mAb were also important. Photodegradation also produced the fragmentation of the mAbs. The damage caused to the mAbs as a result of light-induced aggregation and/or fragmentation was demonstrated both in the medicines and in the diluted preparation forms. These findings should be carefully considered when handling the medicines for administration and when recommending beyond-use dates in normal hospital conditions.

Safety and tolerability of immune globulin intravenous (human), 10% solution in Japanese subjects with mild to moderate Alzheimer's disease

BACKGROUND

Immune globulin intravenous (IGIV), 10% is a donor-derived polyclonal human immunoglobulin G antibody mixture that has potent immune modulatory properties and contains conformation selective anti-amyloid antibodies. We evaluated the safety and tolerability of multiple doses of IGIV, 10% in Japanese patients with mild to moderate Alzheimer's disease.

METHODS

Among the 16 subjects, 12 subjects were assigned to the IGIV group and 4 subjects to the placebo group. Subjects received a total of six infusions of either IGIV at a dose of 0.2 or 0.4 g/kg, or placebo every 2 weeks.

RESULTS

A total of 33 treatment-emergent adverse events (TEAE) occurred in 14 subjects: 13 TEAE in five subjects in both the IGIV 0.2 and 0.4 g/kg groups, and 7 TEAE in four subjects in the placebo group. The most common TEAE in the IGIV subjects were nasopharyngitis, injection-site swelling, and erythema. All 26 TEAE in the IGIV group were considered to be mild. Only one mild TEAE (rash) was considered to be possibly related to the study drug. There were no significant differences in incidence of TEAE between the treatment groups. Four serious TEAE were reported, and all of these were considered to be unrelated to the study treatment. Other assessments related to safety revealed neither clinically significant abnormal values nor findings in the study.

CONCLUSION

IGIV is generally safe and well tolerated with multiple intravenous infusions at doses of 0.2 g/kg and 0.4 g/kg in Japanese patients with mild to moderate Alzheimer's disease.

Effect of microencapsulation shear stress on the structural integrity and biological activity of a model monoclonal antibody, trastuzumab

The aim of the present study was to investigate the influence of process shear stressors on the stability of a model monoclonal antibody, trastuzumab. Trastuzumab, at concentrations of 0.4-4.0 mg/mL, was subjected to sonication, freeze-thaw, lyophilisation, spray drying and was encapsulated into micro- and nanoparticles. The stressed samples were analysed for structural integrity by gel electrophoresis, SDS-PAGE, and size exclusion chromatography (SEC), while the conformational integrity was analysed by circular dichroism (CD). Biological activity of the stressed trastuzumab was investigated by measuring the inhibition of cell proliferation of HER-2 expressing cell lines. Results show that trastuzumab was resistant to the process shear stresses applied and to microencapsulation processes. At the lowest concentration of 0.4 mg/mL, a low percent ( 0.05). The results of this study conclude that trastuzumab may be resistant to various processing stresses. These findings have important implications with respect to pharmaceutical processing of monoclonal antibodies.

Chemical modifications in therapeutic protein aggregates generated under different stress conditions

In this study, we characterized the chemical modifications in the monoclonal antibody (IgG(2)) aggregates generated under various conditions, including mechanical, chemical, and thermal stress treatment, to provide insight into the mechanism of protein aggregation and the types of aggregate produced by the different stresses. In a separate study, additional biophysical characterization was performed to arrange these aggregates into a classification system (Joubert, M. K., Luo, Q., Nashed-Samuel, Y., Wypych, J., and Narhi, L. O. (2011) J. Biol. Chem. 286, 25118-25133). Here, we report that different aggregates possessed different types and levels of chemical modification. For chemically treated samples, metal-catalyzed oxidation using copper showed site-specific oxidation of Met(246), His(304), and His(427) in the Fc portion of the antibody, which might be attributed to a putative copper-binding site. For the hydrogen peroxide-treated sample, in contrast, four solvent-exposed Met residues in the Fc portion were completely oxidized. Met and/or Trp oxidation was observed in the mechanically stressed samples, which is in agreement with the proposed model of protein interaction at the air-liquid interface. Heat treatment resulted in significant deamidation but almost no oxidation, which is consistent with thermally induced aggregates being generated by a different pathway, primarily by perturbing conformational stability. These results demonstrate that chemical modifications are present in protein aggregates; furthermore, the type, locations, and severity of the modifications depend on the specific conditions that generated the aggregates.

Congenital fetal heart block: a potential therapeutic role for intravenous immunoglobulin

BACKGROUND

Congenital heart block affects 2% of all mothers with anti-Ro/La antibodies, can cause heart failure in utero, and has a 20% mortality rate in the first 3 years of life. Maternal fluorinated steroids to prevent or reverse congenital heart block can cause pregnancy complications. Intravenous immunoglobulin (IVIG) has been given with maternal steroids to prevent the recurrence of congenital heart block, although its efficacy is unproven.

CASE

We report the use of IVIG to prevent progression of 2:1 congenital heart block with intermittent complete heart block. After two maternal infusions of IVIG (0.4 g/kg) at 31 weeks of gestation, the fetal heart rate reverted to long periods of sinus rhythm, which was sustained until postnatal life.

CONCLUSION

Our case supports investigating IVIG in the prevention or treatment of this life-threatening condition.

Intravenous immunoglobulins induce potentially synergistic immunomodulations in autoimmune disorders

The increase in platelets in patients with immune thrombocytopenia (ITP) by intravenous administration of human immunoglobulin concentrates (IVIG) reflects a therapeutic immunomodulatory intervention targeted at the disturbed immune response in many inflammatory and autoimmune disorders. These immunoglobulin concentrates contain large numbers of antibodies as well as trace levels of various other immunologically active molecules. Clinical and laboratory studies have documented various mechanisms of action of IVIG. The complex network of immunological reactions resulting from the infusion of IVIG includes changes in several cytokines, interactions with dendritic cells, T- and B- lymphocyte effects, macrophage effects, mediated by distinct Fc-gamma receptors. In addition, effects on complement components and apoptosis have also been observed. Synergism between the different elements of the immune response characterizes the beneficial effects of IVIG in inflammatory and autoimmune disorders. They have immunopathogeneses and clinical manifestations which are difficult to define and therefore IVIG treatment indications remain heterogeneous. Dose finding studies are missing for most of the indications of the drug. In future research, defining the appropriate subgroups of patients should be undertaken. This may be accomplished by prospective registries collecting data on large numbers of patients with long-term follow-up. Controlled clinical and laboratory studies may follow based on new, validated patient selection criteria and focused on mechanisms of action, leading to more evidence-based indications.

Mass spectrometry for structural characterization of therapeutic antibodies

Antibodies, also known as immunoglobulins, have emerged as one of the most promising classes of therapeutics in the biopharmaceutical industry. The need for complete characterization of the quality attributes of these molecules requires sophisticated techniques. Mass spectrometry (MS) has become an essential analytical tool for the structural characterization of therapeutic antibodies, due to its superior resolution over other analytical techniques. It has been widely used in virtually all phases of antibody development. Structural features determined by MS include amino acid sequence, disulfide linkages, carbohydrate structure and profile, and many different post-translational, in-process, and in-storage modifications. In this review, we will discuss various MS-based techniques for the structural characterization of monoclonal antibodies. These techniques are categorized as mass determination of intact antibodies, and as middle-up, bottom-up, top-down, and middle-down structural characterizations. Each of these techniques has its advantages and disadvantages in terms of structural resolution, sequence coverage, sample consumption, and effort required for analyses. The role of MS in glycan structural characterization and profiling will also be discussed.

Adult-onset Still's disease: pathogenesis, clinical manifestations and therapeutic advances

Adult-onset Still's disease (AOSD) is a rare, systemic inflammatory disease of unknown aetiology, characterized by daily high spiking fevers, evanescent rash and arthritis. Our objective was to review the most recent medical literature regarding advances in the understanding of disease pathogenesis, diagnosis and treatment. There is no single diagnostic test for AOSD, and diagnosis is based on clinical criteria and usually necessitates the exclusion of infectious, neoplastic and autoimmune diseases. Laboratory tests are nonspecific and reflect heightened immunological activity with leukocytosis, elevated acute phase reactants and, in particular, extremely elevated serum ferritin levels. Abnormal serum liver function tests are common, while rheumatoid factor and antinuclear antibodies are usually absent. Recent studies of the pathogenesis of the disease have suggested an important role for cytokines. Interleukin (IL)-1, IL-6 and IL-18, macrophage colony-stimulating factor, interferon-gamma and tumour necrosis factor (TNF)-alpha are all elevated in patients with AOSD. Prognosis depends on the course of the disease and tends to be more favourable when systemic symptoms predominate. Treatment includes the use of corticosteroids, often in combination with immunosuppressants (e.g. methotrexate, gold, azathioprine, leflunomide, tacrolimus, ciclosporin and cyclophosphamide) and intravenous immunoglobulin. Biological agents (e.g. anti-TNFalpha, anti-IL-1 and anti-IL-6) have been successfully used in refractory cases. Further progress has been hampered by the rarity and heterogeneity of the disease, which has not permitted the execution of randomized controlled studies.

The use of i.v. IG therapy in dermatology

The intravenous administration of exogenous pooled human immunoglobulin (i.v. IG) was originally licensed as antibody replacement therapy in patients with primary immunodeficiencies and there are currently six FDA-approved uses for this agent. Despite a current lack of FDA approval, off-label treatment of a multitude of dermatologic disorders with i.v. IG has shown exciting potential for this unique treatment modality. The diseases successfully treated with i.v. IG include autoimmune bullous diseases, connective tissue diseases, vasculitides, toxic epidermal necrolysis, and infectious disorders (such as streptococcal toxic shock syndrome). Currently the biggest drawback in the consideration of i.v. IG therapy in dermatologic disorders is the lack of randomized controlled trials. Nevertheless, there is a significant body of evidence demonstrating the efficacy of i.v. IG in patients with dermatologic disorders that are resistant to treatment with standard agents. In summary, i.v. IG constitutes a valuable and potentially life-saving agent in managing patients with a variety of dermatologic disorders under the appropriate circumstances.

Evaluation of a peptide ELISA for the detection of rituximab in serum

Pharmacokinetic studies of therapeutic monoclonal antibodies necessitate the measurement of their biologically active fraction. The aim of this work was to develop an enzyme-linked immunosorbent assay (ELISA) for rituximab, a chimeric anti-CD20 monoclonal antibody, based on its binding to a 20-mer peptide (P20) derived from the extracellular loop of human CD20 (residues 165-184). Derivatives of P20 were prepared by conjugation to bovine serum albumin (BSA-P20ACM) or biotin (Biot-P20ACM). Interactions of P20 and its derived peptides with rituximab were analyzed by surface plasmon resonance (SPR) and by ELISA. A monoclonal anti-idiotype antibody (MB2A4) was used as the reference in each case. SPR analysis showed that P20 (conjugated or unconjugated) had a lower affinity for rituximab than MB2A4. ELISA methods based on P20 or MB2A4 were both highly accurate and reproducible for rituximab measurement in spiked samples, but the MB2A4-based assay had a lower limit of quantification. Interestingly, discrepant results were obtained with the two ELISA methods when analyzing pharmacokinetic samples, with the rituximab concentrations obtained with the MB2A4-based method being systematically higher than those determined by the P20-based method. Possible interference of circulating CD20 with the P20-based method was supported by competition experiments. Rituximab aggregation in the bloodstream may also account for the bias observed in samples from healthy mice. The P20-based ELISA is far less sensitive than the MB2A-based ELISA, thus limiting its utility for pharmacokinetic studies. However, the discrepancy observed between two different approaches for rituximab measurement indicates that data from different studies should be interpreted with care.

Intravenous immunoglobulin: an update on the clinical use and mechanisms of action

Initially used as a replacement therapy for immunodeficiency diseases, intravenous immunoglobulin (IVIg) is now widely used for a number of autoimmune and inflammatory diseases. Considerable progress has been made in understanding the mechanisms by which IVIg exerts immunomodulatory effects in autoimmune and inflammatory disorders. The mechanisms of action of IVIg are complex, involving modulation of expression and function of Fc receptors, interference with activation of complement and the cytokine network and of idiotype network, regulation of cell growth, and effects on the activation, differentiation, and effector functions of dendritic cells, and T and B cells.

Antibody structure, instability, and formulation

The number of therapeutic monoclonal antibody in development has increased tremendously over the last several years and this trend continues. At present there are more than 23 approved antibodies on the US market and an estimated 200 or more are in development. Although antibodies share certain structural similarities, development of commercially viable antibody pharmaceuticals has not been straightforward because of their unique and somewhat unpredictable solution behavior. This article reviews the structure and function of antibodies and the mechanisms of physical and chemical instabilities. Various aspects of formulation development have been examined to identify the critical attributes for the stabilization of antibodies.

A prospective study of the immediate and delayed adverse events following intravenous immunoglobulin infusions

AIM

To document the incidence of immediate and delayed adverse events (AE) following intravenous immunoglobulin (IVIG) infusion in children.

METHODS

Immediate and delayed adverse events were prospectively recorded for 345 infusions in 58 children receiving IVIG for immunodeficiency (n = 33) or immunomodulation (n = 25). For each infusion adverse events were documented during the infusion and by follow up interview 4-7 days later.

RESULTS

Immediate adverse events occurred in 10.3% and delayed adverse events in 41.4% of children treated during the study period. Three and a half per cent of the infusions were associated with immediate AE and 20.9% with delayed adverse events. Headache was the most common delayed AE, occurring in 24.1% of patients and 12.8% of infusions.

CONCLUSIONS

Delayed adverse events to IVIG infusions are common in children. They occur more frequently than immediate adverse events and are the cause of significant morbidity. Recognition of the high frequency of delayed adverse events is important in the care of children receiving IVIG therapy.

Intravenous immunoglobulin in autoimmune disorders: An insight into the immunoregulatory mechanisms

Intravenous immunoglobulin (IGIV) has increasingly been used for the treatment of autoimmune and systemic inflammatory diseases in addition to supportive therapy of immunodeficient patients. IGIV is beneficial in several diseases, including acute and chronic/relapsing diseases, autoimmune diseases and inflammatory disorders. Therapeutic efficacy of IGIV has also been established in a number of dermatologic diseases. Although a considerable progress has been made in understanding the mechanisms by which IGIV exerts immunomodulatory functions in autoimmune diseases, they remain not fully elucidated. The mode of action of IGIV is complex, involving modulation of expression and function of Fc receptors, interference with activation of complement and the cytokine network, modulation of idiotype network, regulation of cell growth, alteration of cellular adhesion process, and effects on the activation differentiation and effector functions of T and B cells and of antigen-presenting cells. The therapeutic effects of IGIV most likely reflect the functions of natural antibodies in maintaining immune homeostasis in healthy people. The ability of IGIV to interact through V regions with complementary V regions of antibodies and antigen receptors as well as with relevant soluble and surface molecules provides the basis for inducing the selection of immune repertoires. Since IGIV is frequently used to treat autoimmune and inflammatory diseases for which evidence of its efficacy is insufficiently documented, controlled trials, particularly of some neurologic and dermatologic diseases, are imperative.

Differences between IGIV products: impact on clinical outcome

The use of immune globulin intravenous (IGIV) as replacement therapy in immunodeficiency disease and as anti-inflammatory or immunomodulatory therapy in a variety of autoimmune and inflammatory diseases has expanded dramatically over the last decade. With this expansion, new challenges and concerns have emerged. As well, new products have been introduced while others have been discontinued. This evolution poses the important issue of product selection, choosing the "right" product for an individual patient. As the manufacturing process, virus reduction methods, and final formulation and composition differ widely among these products, it is intuitive that clinical outcomes, including both safety and efficacy, could also differ. This review examines such differences among currently available products in the United States and their potential to affect clinical outcomes.

Critical Decisions in Selecting an Intravenous Immunoglobulin Product

Use of intravenous immunoglobulin (IVIG) therapy has expanded enormously in the past two to three decades, targeting a large number of autoimmune and inflammatory disorders as well as primary immunodeficiency disease, human immunodeficiency virus, and Kawasaki disease. Increased use, particularly at higher doses and in older patients, has presented certain challenges related to safety and tolerability. All IVIGs are not the same. They differ in manufacturing processes, methods of virus elimination, and final composition. Carefully evaluating patient risk factors and matching them to potential IVIG product risks and benefits are becoming increasingly important in the selection of a particular IVIG.

Cost savings from intravenous immunoglobulin manufactured from chromotography/caprylate (IGIV-C) in persons with primary humoral immunodeficiency disorder

OBJECTIVE

Human intravenous immunoglobulin manufactured with chromatography and caprylate methods (IGIV-C, 10%) was associated with a reduction in validated infections (pneumonia and sinusitis) compared with treatment with a licensed immunoglobulin product manufactured using standard solvent-detergent methods (IGIV-SD, 10%) in participants with primary humoral immunodeficiency disorder (PIDD). Our objective was to determine the cost-consequences of using IGIV-C instead of IGIV-SD.

METHODS

Economic analysis of a double-blind, randomized, clinical trial was used. Participants were randomly assigned to IGIV-C (N = 87) or IGIV-SD (N = 85) and monitored for the development of validated infections over the course of 9 months. Consumed resources were enumerated including cost of physician and emergency room visits, medications (prescription and over-the-counter), work productivity losses, and hospitalizations. Resource data was obtained from case report forms, patient diaries and the trial medication database. Because the amount of IGIV-SD used exceeded that of IGIV-C (nonstatistically significant difference) and the products are equivalently priced, we conservatively excluded investigational product acquisition cost to avoid artificially biasing incremental cost differences. We used a societal perspective with indirect costs, measured in 2003 US dollars. Pricing of both IGIV products is anticipated to be equivalent.

RESULTS

In a multivariate analysis, annual mean per participant costs were significantly lower between those receiving IGIV-C compared with IGIV-SD for prescription medications [-US 302 dollars, 95% confidence interval (CI) -US 598 dollars to -US 6 dollars], hospitalization (-US 1454 dollars, 95% CI -US 1828 dollars to -US 1080 dollars) and total costs (-US 1304 dollars, 95% CI -US 1867 dollars to -US 742 dollars). Costs associated with lost work productivity and physician visits were similar in both groups (P > 0.10). In sensitivity analyses, varying costs of concomitant medications, hospitalization and outpatient care, did not significantly change our results.

CONCLUSION

IGIV-C is cost-saving compared with IGIV-SD among persons with PIDD.

Intravenous Immunoglobulin for Autoimmune Thrombocytopenic Purpura

Severe autoimmune thrombocytopenic purpura is now commonly treated with high doses of intravenous immunoglobulins (IVIGs). Twenty-four years after this treatment was first demonstrated to be effective, several questions remain to be resolved. We review here current knowledge concerning the frequency and type of side effects and the likely mechanism of action of IVIGs. We suggest that the currently recommended dose of IVIG (2 g/kg) could be halved, that the total dose of IVIG should be administered as a single infusion, that nonresponders could be provided another equal dose on day 3, and that IVIG plus prednisolone should be considered the gold standard for treatment of the most severe forms of the disease. Treatment with anti-D immunoglobulin could be proposed as an alternative if the results recently obtained with high doses (75 microg/kg) are confirmed. Finally, because IVIG has only a transient effect, it cannot be considered a curative treatment for patients with chronic autoimmune thrombocytopenic purpura.

Efficacy of intravenous immunoglobulin in chronic idiopathic pericarditis: report of four cases

Human intravenous immunoglobulins (hIVIgs) are used in two broad categories of diseases: immunodeficiency and autoimmunity. Among the immune-mediated diseases hIVIgs are of benefit in idiopathic thrombocytopenic purpura, autoimmune hemolytic anemia, and dermatomyositis. Chronic idiopathic pericarditis (CIP) is a chronic disease of unknown origin characterized by recurrent episodes of pericardial inflammation. The cause of the recurrence is unknown, although in some cases it may be traced to a viral infection and to the presence of antimyocardial antibodies. Since a viral infection can induce an autoimmune process through a mechanism of molecular mimicry, and since the optimal therapy for prevention of the recurrences has not been established, we reasoned that treatment with hIVIgs could be beneficial in our patients unresponsive to previous immunosuppressive therapies. We describe four patients affected by CIP treated with monthly high-dose hIVIgs (0.4 g/kg daily for 5 consecutive days) for five times followed by administration every 2 months. Three of the four patients could permanently discontinue steroid therapy and are still in remission after years of follow-up. Our experience suggests that hIVIgs therapy may be a useful and safe treatment for CIP in steroid-dependent patients.

Intravenous immunoglobulin and autoimmune thrombocytopenic purpura: 22 years on

Autoimmune thrombocytopenic purpura is now commonly treated with high doses of intravenous immunoglobulins. Twenty-two years after this treatment was first shown to be effective, several questions remain. We review here current knowledge concerning the frequency and type of side-effects and the probable mechanism of action of intravenous immunoglobulins. We suggest that the currently recommended dose of intravenous immunoglobulins (2 g/kg body weight) could be halved, that the total dose of intravenous immunoglobulins should be administered as a single infusion, that non-responders could be given another equal dose on day 3, and that intravenous immunoglobulins plus prednisolone should be considered as the gold standard for treatment of the most severe forms of the disease. Finally, as intravenous immunoglobulins have only a transient effect, they cannot be considered as a curative treatment for patients with chronic autoimmune thrombocytopenic purpura.

Efficacy, tolerability, safety and pharmacokinetics of a nanofiltered intravenous immunoglobulin: studies in patients with immune thrombocytopenic purpura and primary immunodeficiencies

BACKGROUND AND OBJECTIVES

A nanofiltration step with the capacity to reduce blood-borne pathogens was introduced into the manufacturing process of intravenous immunoglobulin (IVIG). In order to demonstrate the efficacy, safety and pharmacokinetics of the modified product, we conducted Phase II/III studies comparing the nanofiltered IVIG (IVIG-N) with its parent product, Sandoglobulin, in patients with chronic immune thrombocytopenic purpura (ITP) and primary immunodeficiencies (PID).

MATERIALS AND METHODS

Patients with ITP (n = 27) with platelet counts of < 20 x 10(9)/l were treated with Sandoglobulin or IVIG-N infusions at a dose of 0.4 g/kg body weight on five consecutive days. The primary efficacy end-point was the number of patients with an increase in platelet counts to > 50 x 10(9)/l. Secondary end-points were time to and duration of response, and regression of bleeding. Patients with PID (n = 36) were treated for 6 months with Sandoglobulin or IVIG-N at doses of 0.2-0.8 g/kg, infused at 3- or 4-week intervals. The primary end-point was the number of days absent from school/work. Secondary end-points were hospitalization, use of antibiotics and feeling of well-being. In both studies, tolerability was assessed by recording of adverse events and laboratory determinations. Viral safety was ascertained by serology supplemented with nucleic acid detection methods. Pharmacokinetics were analysed in patients with PID using serum concentration-time data for immunoglobulin G (IgG), and IgG antibodies to hepatitis B surface antigen (anti-HBsAg).

RESULTS

In the ITP study, the primary end-point was met by 12/16 patients on IVIG-N and by 10/10 patients on Sandoglobulin (P = 0.123). A shift towards lesser bleeding intensity was seen in both groups. In the PID study, seven of 18 patients on IVIG-N and six of 16 patients on Sandoglobulin missed days at work/school, with monthly mean absences of 0.4 and 0.5 days (P = 0.805). The feeling of well-being was comparable in both groups. In the ITP study, adverse events with a causal relationship to medication were suspected in six patients on IVIG-N and in seven on Sandoglobulin. In the PID study, three patients on IVIG-N and two on Sandoglobulin experienced possible drug-related adverse events. In both studies, serological and polymerase chain reaction (PCR) tests gave evidence for virus safety. Pharmacokinetics showed constant peak and trough serum IgG levels in all patients, indicating almost steady-state conditions for both formulations. The overall half-life (t1/2) for total IgG was 33 +/- 17 days in the IVIG-N arm and 25 +/- 16 days in the Sandoglobulin arm; for anti-HBsAg t1/2, values were 17 +/- 7 and 17 +/- 9 days, respectively.

CONCLUSIONS

IVIG-N is efficacious, well tolerated and safe in patients with ITP and PID. Its pharmacokinetic properties were comparable to those of Sandoglobulin.