Clinically approved IVIg delivered to the hippocampus with focused ultrasound promotes neurogenesis in a model of Alzheimer's disease.

Preclinical and clinical data support the use of focused ultrasound (FUS), in the presence of intravenously injected microbubbles, to safely and transiently increase the permeability of the blood-brain barrier (BBB). FUS-induced BBB permeability has been shown to enhance the bioavailability of administered intravenous therapeutics to the brain. Ideal therapeutics candidates for this mode of delivery are those capable of inducing benefits peripherally following intravenous injection and in the brain at FUS-targeted areas. In Alzheimer's disease, intravenous immunoglobulin (IVIg), a fractionated human blood product containing polyclonal antibodies, act as immunomodulator peripherally and centrally, and it can reduce amyloid pathology in the brain. Using the TgCRND8 mouse model of amyloidosis, we tested whether FUS can improve the delivery of IVIg, administered intravenously (0.4 g/kg), to the hippocampus and reach an effective dose to reduce amyloid plaque pathology and promote neurogenesis. Our results show that FUS-induced BBB permeability is required to deliver a significant amount of IVIg (489 ng/mg) to the targeted hippocampus of TgCRN8 mice. Two IVIg-FUS treatments, administered at days 1 and 8, significantly increased hippocampal neurogenesis by 4-, 3-, and 1.5-fold in comparison to saline, IVIg alone, and FUS alone, respectively. Amyloid plaque pathology was significantly reduced in all treatment groups: IVIg alone, FUS alone, and IVIg-FUS. Putative factors promoting neurogenesis in response to IVIg-FUS include the down-regulation of the proinflammatory cytokine TNF-α in the hippocampus. In summary, FUS was required to deliver an effective dose of IVIg to promote hippocampal neurogenesis and modulate the inflammatory milieu.

Steady-State Serum IgG Trough Levels Are Adequate for Pharmacokinetic Assessment in Patients with Immunodeficiencies Receiving Subcutaneous Immune Globulin.

Patients with primary immunodeficiency diseases often require lifelong immunoglobulin (IG) therapy. Most clinical trials investigating IG therapies characterize serum immunoglobulin G (IgG) pharmacokinetic (PK) profiles by serially assessing serum IgG levels. This retrospective analysis evaluated whether steady-state serum IgG trough level measurement alone is adequate for PK assessment. Based on individual patient serum IgG trough levels from two pivotal trials (phase 2/3 European [NCT01412385] and North American [NCT01218438]) of weekly 20% subcutaneous IG (SCIG; Cuvitru, Ig20Gly), trough level-predicted IgG AUC (AUCτ,tp) were calculated and compared with the reported AUC calculated from serum IgG concentration-time profiles (AUCτ). In both studies, mean AUCτ,tp values for Ig20Gly were essentially equivalent to AUCτ with point estimates of geometric mean ratio (GMR) of AUCτ,tp/AUCτ near 1.0 and 90% CIs within 0.80-1.25. In contrast, for IVIG, 10%, mean AUCτ,tp values were lower than AUCτ by >20%, (GMR [90% CI]: 0.74 [0.70-0.78] and 0.77 [0.73-0.81] for the two studies, respectively). Mean AUCτ,tp values calculated for 4 other SCIG products (based on mean IgG trough levels reported in the literature/labels) were also essentially equivalent to the reported AUCτ (differences <10% for all except HyQvia, a facilitated SCIG product), while differences for IVIG products were >20%. In conclusion, steady-state serum IgG levels following weekly SCIG remain stable, allowing for reliable prediction of AUC over the dosing interval using trough IgG levels. These findings indicate that measuring steady-state serum IgG trough levels alone may be adequate for PK assessment of weekly SCIG.

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.

Phase 1 study of PSMA ADC, an antibody-drug conjugate targeting prostate-specific membrane antigen, in chemotherapy-refractory prostate cancer.

BACKGROUND: Prostate-specific membrane antigen (PSMA) is a well-characterized target that is overexpressed selectively on prostate cancer cells. PSMA antibody-drug conjugate (ADC) is a fully human IgG1 monoclonal antibody conjugated to the microtubule disrupting agent monomethyl auristatin E (MMAE), which is designed to specifically bind PSMA-positive cells, internalize, and then release its cytotoxic payload into the cells. PSMA ADC has demonstrated potent and selective antitumor activity in preclinical models of advanced prostate cancer. A Phase 1 study was conducted to assess the safety, pharmacokinetics, and preliminary antitumor effects of PSMA ADC in subjects with treatment-refractory prostate cancer. METHODS: In this first-in-man dose-escalation study, PSMA ADC was administered by intravenous infusion every three weeks to subjects with progressive metastatic castration-resistant prostate cancer (mCRPC) who were previously treated with docetaxel chemotherapy. The primary endpoint was to establish a maximum tolerated dose (MTD). The study also examined the pharmacokinetics of the study drug, total antibody, and free MMAE. Antitumor effects were assessed by measuring changes in serum prostate-specific antigen (PSA), circulating tumor cells (CTCs), and radiologic imaging. RESULTS: Fifty-two subjects were administered doses ranging from 0.4 to 2.8 mg/kg. Subjects had a median of two prior chemotherapy regimens and prior treatment with abiraterone and/or enzalutamide. Neutropenia and peripheral neuropathy were identified as important first-cycle and late dose-limiting toxicities, respectively. The dose of 2.5 mg/kg was determined to be the MTD. Pharmacokinetics were approximately dose-proportional with minimal drug accumulation. Reductions in PSA and CTCs in subjects treated with doses of ≥1.8 mg/kg were durable and often concurrent. CONCLUSIONS: In an extensively pretreated mCRPC population, PSMA ADC demonstrated acceptable toxicity. Antitumor activity was observed over dose ranges up to and including 2.5 mg/kg. The observed anti-tumor activity supported further evaluation of this novel agent for the treatment of advanced metastatic prostate cancer.

Immunoglobulin prophylaxis in pediatric hematopoietic stem cell transplant.

BACKGROUND: After allogeneic hematopoietic stem cell transplantation (HSCT), patients have an increased susceptibility to infections, thought to be due in part to hypogammaglobulinemia. Thus, prophylactic administration of intravenous immunoglobulins (IVIG) has been administered to patients after HSCT as standard of care. This study compares the viral infection rate between dosing IVIG by IgG levels versus by routine monthly administration in pediatric patients after HSCT. PROCEDURE: In this retrospective chart review, we abstracted from electronic medical records data on pediatric patients undergoing HSCT from 2010 to 2012 for 6 months post-HSCT. We compared rates of infection between patients treated with routine IVIG prophylaxis and patients given IVIG prophylaxis based on IgG tough levels (IgG levels were checked every 2 weeks). RESULTS: Data were available and reviewed for 50 patients dosed with IVIG every 28 days (Group 1) and 100 patients dosed with IVIG based on IgG level > 400 mg/dl (Group 2). There was no significant difference in age (P = 0.98) or sex (P = 0.42), reason for HSCT, alemtuzumab use (P = 0.602), or reduced intensity conditioning (P = 1.00). Significantly more haploidentical donors were in Group 1 (P = 0.04), otherwise there was no significant difference in donor type between groups. Significantly less acute graft versus host disease occurred (P = <0.001) in Group 2 (P = <0.001). PCR documented viral infections were not significantly different (P = 0.412) (Table 1). Group 2 patients received significantly less IVIG (P < 0.001). CONCLUSION: Dosing IVIG to maintain an IgG level > 400 mg/dl is a cost-effective and safe way to prevent viral infections in pediatric patients undergoing HSCT.

Controlled tetra-Fc sialylation of IVIg results in a drug candidate with consistent enhanced anti-inflammatory activity.

Despite the beneficial therapeutic effects of intravenous immunoglobulin (IVIg) in inflammatory diseases, consistent therapeutic efficacy and potency remain major limitations for patients and physicians using IVIg. These limitations have stimulated a desire to generate therapeutic alternatives that could leverage the broad mechanisms of action of IVIg while improving therapeutic consistency and potency. The identification of the important anti-inflammatory role of fragment crystallizable domain (Fc) sialylation has presented an opportunity to develop more potent Ig therapies. However, translating this concept to potent anti-inflammatory therapeutics has been hampered by the difficulty of generating suitable sialylated products for clinical use. Therefore, we set out to develop the first, to our knowledge, robust and scalable process for generating a well-qualified sialylated IVIg drug candidate with maximum Fc sialylation devoid of unwanted alterations to the IVIg mixture. Here, we describe a controlled enzymatic, scalable process to produce a tetra-Fc-sialylated (s4-IVIg) IVIg drug candidate and its qualification across a wide panel of analytic assays, including physicochemical, pharmacokinetic, biodistribution, and in vivo animal models of inflammation. Our in vivo characterization of this drug candidate revealed consistent, enhanced anti-inflammatory activity up to 10-fold higher than IVIg across different animal models. To our knowledge, this candidate represents the first s4-IVIg suitable for clinical use; it is also a valuable therapeutic alternative with more consistent and potent anti-inflammatory activity.

Efficacy and Safety of a New 10% Intravenous Immunoglobulin Product in Patients with Primary Immune Thrombocytopenia (ITP).

BACKGROUND: In the current study, we aimed to investigate the efficacy and safety of intravenous immunoglobulin (IVIg)-SN 10%, a new 10% IVIg formulation, in adult patients with severe primary immune thrombocytopenia (ITP; platelet count < 20 × 109/L). METHODS: Patients diagnosed as primary ITP, aged 19 years old or more, and had a platelet count of < 20 × 109/L by screening complete blood cell count performed within 2 weeks of study commencement were eligible. Patients received IVIg-SN 10% at a dose of 1 g/kg/day for two consecutive days. Response was defined as the achievement of a platelet count of ≥ 50 × 109/L at day 8. RESULTS: Out of 81 eligible patients, 31 patients were newly diagnosed, 7 patients had persistent ITP, and 43 patients had chronic ITP. In intent-to-treat analysis, 61.3 patients (75.7%) achieved response and satisfied the pre-defined non-inferiority condition. Median time to response was 2 days and mean duration of maintaining response after the completion of IVIg therapy was 9.13 ± 8.40 days. Response rates were not found to be dependent on the phase of ITP or previous treatment for ITP. The drug was well tolerated and the frequency of mucocutaneous bleeding decreased during the study period. CONCLUSION: In summary, IVIg-SN 10% formulation was found to be safe and effective in adult ITP patients (Trial registry at ClinicalTrials.gov, NCT02063789).

Binding Performance of Human Intravenous Immunoglobulin and 20(S)-7-Ethylcamptothecin.

A previous study showed that intravenous immunoglobulin (IVIG) could preserve higher levels of biologically active lactone moieties of topotecan, 7-ethyl-10-hydroxycamptothecin (SN-38) and 10-hydroxycamptothecin at physiological pH 7.40. As one of camptothecin analogues (CPTs), the interaction of 7-ethylcamptothecin and IVIG was studied in vitro in this study. It was shown that the main binding mode of IVIG to 7-ethylcamptothecin was hydrophobic interaction and hydrogen bonding, which is a non-specific and spontaneous interaction. The hydrophobic antigen-binding cavity of IgG would enwrap the drug into a host-guest inclusion complex and prevent hydrolysis of the encapsulated drug, while the drug is adjacent to the chromophores of IgG and may exchange energy with chromophores and quench the fluorescence of the protein. Also, the typical ß-sheet structure of IVIG unfolded partially after binding to 7-ethylcamptothecin. Additionally, the binding properties of IVIG and six CPTs with different substituents at A-ring and/or B-ring including camptothecin, topotecan, irinotecan, 10-hydroxycamptothecin, 7-ethylcamptothecin and SN-38 were collected together and compared each other. Synergizing with anti-cancer drugs, IVIG could be used as a transporter protein for 7-ethylcamptothecin and other CPTs, allowing clinicians to devise new treatment protocols for patients.

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.

Emerging Paradigm of Primary Immunodeficiency Disease: Individualizing Immunoglobulin Dose and Delivery to Enhance Outcomes.

An emerging paradigm for the treatment of primary immunodeficiency disease (PIDD) with immunoglobulin (IgG) replacement therapy emphasizes the tailoring of treatments to each patient with the goal of preventing infections and minimizing side effects. Increasing evidence shows that the IgG dose needed to prevent infection varies with each patient, and both intravenous immunoglobulin (IGIV) and subcutaneous immunoglobulin (IGSC) have emerged as feasible modes of delivery. Although IGIV is currently the routine treatment, IGSC is increasingly being chosen as the preferred route of delivery due to greater flexibility and reduced side effects.

Evaluation of the Safety, Tolerability, and Pharmacokinetics of Gammaplex® 10% Versus Gammaplex® 5% in Subjects with Primary Immunodeficiency.

PURPOSE: This phase 3, multicenter, open-label, randomized, two-period, crossover bioequivalence trial evaluated the safety, tolerability, and pharmacokinetics of intravenous immunoglobulins (IVIGs) Gammaplex 5% and Gammaplex 10% in 33 adults and 15 children with primary immunodeficiency diseases (PIDs). METHODS: Eligible adults received five Gammaplex 5% infusions followed by five Gammaplex 10% infusions, or vice versa, stratified by a 21- or 28-day dosing regimen. Pediatric subjects received five Gammaplex 10% infusions only. RESULTS: The primary objective, to demonstrate the bioequivalence of Gammaplex 10% and Gammaplex 5% at the 28-day dosing interval, was met based on the Gammaplex 10%/Gammaplex 5% ratio of area under the concentration versus time curve (AUC0-28) values. Throughout the study, total immunoglobulin G trough levels were well maintained, with total values generally ≥600 mg/dL (minimum level for study inclusion). At the dosing schedules and infusion rates used in this study, safety and tolerability were comparable and acceptable in adult and pediatric PID subjects treated with Gammaplex 10% and 5%. CONCLUSIONS: In this study, the first direct comparison of 5% IVIG and 10% IVIG products in PID subjects, the pharmacokinetic analysis demonstrated bioequivalence of Gammaplex 10% and Gammaplex 5% at the 28-day dosing interval. The Gammaplex 10% formulation was safe and well tolerated in pediatric and adult PID subjects. Based on the results from this bridging study in PID subjects, Gammaplex 10% could be expected to have a therapeutic effect similar to the licensed Gammaplex 5%, which has demonstrated efficacy and tolerability in patients with PID and idiopathic thrombocytopenic purpura.

Considerations for dosing immunoglobulin in obese patients.

Obesity is a very common condition; however, the effect of excess body weight on the appropriate dose of immunoglobulin has not been defined empirically. The proposed pharmacokinetic differences between lean and obese patients and the opportunity to reduce costs has led to the proposition that obese patients should receive proportionally lower doses of immunoglobulin once a certain threshold is reached. Here the theoretical factors which could affect dosing in obese patients are considered alongside the available empirical evidence. The available evidence indicates that obesity may affect the pharmacokinetics of immunoglobulin; however, the effect is likely to be too small to have a clinically important effect on dosing. Wide interpatient individuality and highly variable clinical need mean that obesity should not play a major factor in dosing considerations. However, patients who are obese are more likely to have multiple cardiovascular risk factors and their weight indicates a large dose. This puts these patients at a higher risk of adverse reactions, and therefore caution is advised.

Efficacy, safety, tolerability and pharmacokinetics of a novel human immune globulin subcutaneous, 20%: a Phase 2/3 study in Europe in patients with primary immunodeficiencies.

A highly concentrated (20%) immunoglobulin (Ig)G preparation for subcutaneous administration (IGSC 20%), would offer a new option for antibody replacement therapy in patients with primary immunodeficiency diseases (PIDD). The efficacy, safety, tolerability and pharmacokinetics of IGSC 20% were evaluated in a prospective trial in Europe in 49 patients with PIDD aged 2-67 years. Over a median of 358 days, patients received 2349 IGSC 20% infusions at monthly doses equivalent to those administered for previous intravenous or subcutaneous IgG treatment. The rate of validated acute bacterial infections (VASBIs) was significantly lower than 1 per year (0·022/patient-year, P < 0·0001); the rate of all infections was 4·38/patient-year. Median trough IgG concentrations were ≥ 8 g/l. There was no serious adverse event (AE) deemed related to IGSC 20% treatment; related non-serious AEs occurred at a rate of 0·101 event/infusion. The incidence of local related AEs was 0·069 event/infusion (0·036 event/infusion, when excluding a 13-year-old patient who reported 79 of 162 total related local AEs). The incidence of related systemic AEs was 0·032 event/infusion. Most related AEs were mild, none were severe. For 64·6% of patients and in 94·8% of IGSC 20% infusions, no local related AE occurred. The median infusion duration was 0·95 (range = 0·3-4·1) h using mainly one to two administration sites [median = 2 sites (range = 1-5)]. Almost all infusions (99·8%) were administered without interruption/stopping or rate reduction. These results demonstrate that IGSC 20% provides an effective and well-tolerated therapy for patients previously on intravenous or subcutaneous treatment, without the need for dose adjustment.

Flebogamma(®) 5 % DIF Intravenous Immunoglobulin for Replacement Therapy in Children with Primary Immunodeficiency Diseases.

PURPOSE: The previous studies with Flebogamma(®) 5 % DIF intravenous immunoglobulin (IVIG) contained insufficient numbers of pediatric subjects to fully warrant a pediatric indication by the FDA. The objective of this study was to evaluate the efficacy, safety, and pharmacokinetics of Flebogamma® 5 % DIF for replacement therapy in children (age 2-16) with primary immunodeficiency diseases (PIDD). METHODS: IVIG was administered at eight clinical sites to 24 subjects with well-defined PIDD at a dose of 300-800 mg/kg every 21-28 days for 12 months. The pharmacokinetics endpoint in this study was the dose-adjusted increment of the serum IgG trough levels. RESULTS: The calculated serious bacterial infection rate was 0.05/subject/year. The incidence of adverse events considered potentially related to IVIG during or within 72 h after completing an infusion was within the FDA guidance threshold of <40 % at each time point. Dose-adjusted incremental IgG levels remained approximately equal to or slightly greater than pre-study IgG levels (between 800 and 1000 mg/dL throughout) when the subjects were treated with IVIG therapy other than Flebogamma(®) DIF 5 % indicating no evidence of a different pharmacokinetic profile in this pediatric population if compared to those profiles in previous Flebogamma studies in predominately adult populations. CONCLUSIONS: Flebogamma(®) 5 % DIF is efficacious and safe, has adequate pharmacokinetic properties, is well-tolerated, and maintains the profile of Flebogamma(®) 5 % for the treatment of children with primary humoral immunodeficiency diseases.

Efficacy, Safety, and Pharmacokinetics of a Novel Human Immune Globulin Subcutaneous, 20 % in Patients with Primary Immunodeficiency Diseases in North America.

Patients with primary immunodeficiency disease (PIDD) typically require life-long intravenous (IV) or subcutaneous (SC) immunoglobulin (Ig) replacement therapy to prevent recurrent infections. The efficacy, safety, and pharmacokinetics of a highly concentrated (20 %) Ig preparation for SC administration (IGSC 20 %) were evaluated in a prospective trial in patients with PIDD. A total of 74 patients (aged 3-83 years) received 4327 IGSC 20 % infusions over a median of 380.5 days. The rate of validated serious bacterial infections was 0.012 event/patient-year (p < 0.0001 compared with the historical control), and the annualized rate of infection was 2.41 events/patient. Median IgG trough levels were >14.5 g/l. The median maximum infusion rate was 60 ml/h/site (range 4.4-180), resulting in a median infusion duration of 0.95 h. A volume ≥30 ml was infused per site in 74.8 % of IGSC 20 % infusions. Most (84.9 %) infusions were administered using ≤2 infusion sites; for 99.8 % of infusions, there was no need to interrupt/stop administration or reduce the infusion rate. No related serious adverse event (AE) occurred during IGSC 20 % treatment; related non-serious AEs occurred at a rate of 0.036 event/infusion. The incidence of related local AEs was 0.015 event/infusion and of related systemic AEs was 0.021 event/infusion; most were mild in severity, none severe. Increased infusion rates or volumes were not associated with higher AE rates. The investigated IGSC 20 % treatment was shown to be effective and safe, enabling higher infusion rates and volumes per site compared to conventional SC treatments, resulting in fewer infusion sites and shorter infusion durations.

An open, prospective trial investigating the pharmacokinetics and safety, and the tolerability of escalating infusion rates of a 10% human normal immunoglobulin for intravenous infusion (IVIg), BT090, in patients with primary immunodeficiency disease.

BACKGROUND AND OBJECTIVES: Pharmacokinetics, safety and tolerability of escalating infusion rates of BT090, a 10% intravenous immunoglobulin (IVIg), were studied in patients with primary immunodeficiency disease. MATERIALS AND METHODS: In Part A, patients (n = 30) received 3 infusions of BT090 at their pretrial dose and dosing interval; the infusion rate of BT090 was increased from 0·3 to 1·4 to 2·0 ml/kg/h for each infusion in each patient initially at 30-min intervals. Pharmacokinetics was evaluated at the 3rd infusion (n = 24). At the 4th infusion, infusion rates were to be gradually escalated from 0·3 to 1·4 to 4·0 to a maximum of 8·0 ml/kg/h initially at 30-min intervals to establish the maximum tolerated infusion rate per patient. RESULTS: The pharmacokinetic characteristics and safety profile of BT090 were comparable with those of other IVIgs, including Intratect(®) . Escalation of infusion rates was well tolerated, allowing identification of individual patient's maximum tolerated infusion rate. At subsequent infusions, all patients tolerated their individually defined maximum infusion rate: 17 patients (68·0%) tolerated infusion rates of 6·0 or 8·0 ml/kg/h and four patients (16%) had maximum tolerated infusion rates of <4·0 ml/kg/h at subsequent infusions. Escalation of infusion rates shortened infusion time from a median of around 2·5 h to around 1·6 h. SAEs were reported in three patients, but none was related to BT090 treatment. CONCLUSIONS: Shortening infusion time may reduce overall healthcare spending, for example nursing time needed, and also minimize disruption of patients' daily routine, especially for those patients in work or school settings.

The original sins of clinical trials with intravenous immunoglobulins in sepsis.

Intravenous immunoglobulins (IVIGs) have not yet demonstrated robust evidence in the benefit for treatment of sepsis. In spite of multiple clinical trials performed with IVIG in sepsis, it remains an experimental therapy for this severe condition. Nonetheless, these trials do not address a number of potential confounding factors, concerning both the patient and the IVIG preparations, which could greatly affect the final result. To name a few, endogenous levels of immunoglobulin isotypes and subclasses are not assessed prior to treatment. The presence/absence of patient antibodies against the microorganism(s) causing sepsis is not evaluated. The accuracy of antibiotic prescription is not included as an adjusting variable. The degree of patient immunosuppression (previous or induced by sepsis) is not documented. In turn, the concentration and antimicrobial specificities of the antibodies contained in the batches of IVIG are not assessed. Neither the pharmacokinetics of IVIG nor its potential immunomodulatory effects are evaluated. In addition, the concept of 'window of opportunity' for IVIG administration following diagnosis of sepsis is not considered. In conclusion, addressing these factors could help to individualise treatment with IVIG for sepsis, which could enhance the opportunities of this drug to show benefits in terms of survival in this severe condition.

Subcutaneous immunoglobulin in lymphoproliferative disorders and rituximab-related secondary hypogammaglobulinemia: a single-center experience in 61 patients.

Intravenous immunoglobulin replacement therapy represents the standard treatment for hypogammaglobulinemia secondary to B-cell lymphoproliferative disorders. Subcutaneous immunoglobulin infusion is an effective, safe and well-tolerated treatment approach in primary immunodeficiencies but no extensive data are available on their use in secondary hypogammaglobulinemia, a frequent phenomenon occurring after treatment with anti-CD20 monoclonal antibodies in lymphoproliferative disorders. In this retrospective study we evaluated efficacy (serum IgG trough levels, incidence of infections per year, need for antibiotics) and safety (number of adverse events) of intravenous (300 mg/kg/4 weeks) versus subcutaneous (75 mg/kg/week) immunoglobulin replacement therapy in 61 patients. In addition, the impact of the infusion methods on quality of life was compared. All patients were treated with subcutaneous immunoglobulin, and 33 out of them had been previously treated with intravenous immunoglobulin. Both treatments appeared to be effective in replacing Ig production deficiency and in reducing the incidence of infectious events and the need for antibiotics. Subcutaneous immunoglobulin obtained a superior benefit when compared to intravenous immunoglobulin achieving higher IgG trough levels, lower incidence of overall infection and need for antibiotics. The incidence of serious bacterial infections was similar with both infusion ways. As expected, a lower number of adverse events was registered with subcutaneous immunoglobulin, compared to intravenous immunoglobulin, with no serious adverse events. Finally, we observed an improvement in health-related quality of life parameters after the switch to subcutaneous immunoglobulin. Our results suggest that subcutaneous immunoglobulin is safe and effective in patients with hypogammaglobulinemia associated to lymphoproliferative disorders.

Pharmacokinetics of intravenous immunoglobulin in multifocal motor neuropathy.

BACKGROUND: Multifocal motor neuropathy (MMN) is often responsive to treatment with intravenous immunoglobulin (IVIg), but the optimal dose and intervals of IVIg maintenance treatment have not been established. Increase in IgG concentration (ΔIgG) after IVIg infusion has recently been identified as determinant of outcome in Guillain-Barré syndrome. ΔIgG may therefore represent a potentially useful biomarker to optimise IVIg dosing in patients with MMN. OBJECTIVE: The aims of this study were to determine variability of IVIg pharmacokinetics in patients with MMN in relation to treatment response, and to establish whether interindividual differences in IVIg pharmacokinetics were associated with genetic polymorphisms of the endothelial IgG receptor (FcRn) which determines IgG half-life. METHODS: Twenty-three patients with MMN receiving their first IVIg treatment at a cumulative dose of 2.0 g/kg in 5 days were included. A good treatment response was defined as an increase in muscle strength of at least one Medical Research Council point in minimally two muscle groups. IgG concentrations in serum were determined at baseline, at day 1 and day 5 of the IVIg course, and 3 weeks after treatment. FcRn copy number variation and differences in repeat length of the variable number of tandem repeats in the FcRn gene were determined by quantitative PCR and Sanger sequencing. RESULTS: Seventeen patients (74%) had a good response to treatment. Total IgG and ΔIgG levels showed large variation between patients. Mean ΔIgG was higher in IVIg responders than in non-responders, with the largest difference on day 1 (11.1 g/L vs 4.5 g/L, p=0.06), but our study lacked power to show statistically significant differences. Genetic variation in the FcRn gene was not associated with ΔIgG levels or response to treatment. CONCLUSIONS: IVIg pharmacokinetics varies in patients with MMN and may be associated with clinical response.

Effect of anthrax immune globulin on response to BioThrax (anthrax vaccine adsorbed) in New Zealand white rabbits.

Development of anthrax countermeasures that may be used concomitantly in a postexposure setting requires an understanding of the interaction between these products. Anthrax immune globulin intravenous (AIGIV) is a candidate immunotherapeutic that contains neutralizing antibodies against protective antigen (PA), a component of anthrax toxins. We evaluated the interaction between AIGIV and BioThrax (anthrax vaccine adsorbed) in rabbits. While pharmacokinetics of AIGIV were not altered by vaccination, the vaccine-induced immune response was abrogated in AIGIV-treated animals.