Efficacy, Safety, and Pharmacokinetics of a New 10 % Liquid Intravenous Immunoglobulin Containing High Titer Neutralizing Antibody to RSV and Other Respiratory Viruses in Subjects with Primary Immunodeficiency Disease

Immune reconstitution and survival, following hematopoietic stem cell transplantation in Omani patients with inborn errors of immunity

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is a curative treatment for certain inborn errors of immunity.

METHODS

A 17-year retrospective cohort study was conducted on 40 immunodeficient patients who underwent HSCT.

RESULTS

The median age at transplant was 11.0 months (4.6-61.0). Donors were primarily matched sibling donors (60%). 90% and 85% of patients received conditioning and graft-versus-host disease (GVHD) prophylaxis, respectively. The mean donor chimerism at the last follow-up was 88.6% ± 17.9% (40-100). Median serum immunoglobulin (Ig) G level, CD4+ T-cell count, and CD19+ B-cell count were 11.7 g/L (9.2-13.6), 0.9 × 109/L 0.6-1.2), and 0.5 × 109/L (0.2-0.7), respectively. 29 patients (72.5%) received intravenous immunoglobulins (IVIG) therapy, with a median duration of 10.0 months (4.0-14.0). The median post-transplant follow-up was 6.5 years (IQR:1.4-11.5). The 10-year overall probability of survival is 84.3%.

CONCLUSION

Monitoring IRC is important in ensuring adequate disease-free survival.

Case Report: ASCENIV use in three young children with immune abnormalities and acute respiratory failure secondary to RSV infection

Respiratory syncytial virus (RSV) is the most common etiology of bronchiolitis in young children. While most children clinically improve with care at home, RSV is the leading cause of hospitalization among infants aged 12 months or less. Common modalities of treatment for children with immune dysregulation include respiratory support and best supportive care, which may include immunoglobulin therapy. All immunoglobulin therapies adhere to Food and Drug Administration (FDA) - established standards for antibodies against measles, polio, and diphtheria, but there are no required standards for problematic respiratory viral pathogens, including RSV and others. ASCENIV is an approved IVIG that is manufactured from blending normal source plasma with plasma from donors that possess high antibody titers against RSV and other respiratory pathogens of concern. ASCENIV was developed, in part, to the unmet need that exists in immunocompromised patients who lack sufficient antibodies against problematic viral pathogens. ASCENIV is not a currently approved treatment for severe RSV and other viral infections. There is a lack of research regarding its potential benefits in the acute treatment period for RSV and in the pediatric population. Therefore, this case series was developed to describe real-world experiences of ASCENIV use in this less well studied clinical scenario. This case series reviews three pediatric patients ≤ 5 years of age with immune dysregulation and who were severely ill with RSV. Despite receiving best supportive care, and standard immunoglobulin therapy for some, the patients' clinical status continued to decline. All patients received ASCENIV in an intensive care setting. Each patient had ultimately recovered due to the various medical interventions done. This case series demonstrated that ASCENIV (500mg/kg) administration may have contributed to the treatment outcomes of a less well studied age-cohort of patients. In addition, no adverse side effects were observed after ASCENIV administration. Further analysis of the benefits of ASCENIV for the acute and preventative treatment in patients younger than 12 years of age with immune dysregulation should continue to be explored.

In-vivo and human evidence for potential efficacy of therapeutic polyclonal RSV neutralizing antibodies for palivizumab-resistant RSV infections

BACKGROUND

Monoclonal antibody (palivizumab), intravenous immune globulin (IGIV), or respiratory syncytial virus (RSV)-polyclonal-hyperimmune-globulin (RSV-IG as Respigam®, RI-001, RI-002) are used with ribavirin in RSV-infected immunocompromised patients, with debated efficacy. Palivizumab-resistance (PR) can arise during treatment of persistent infections in this population. RSV-IG may confer benefit in PR-RSV infection.

METHODS

RSV-IG [RI-001] was provided for an immunocompromised infant with RSV-pneumonitis refractory to ribavirin and palivizumab. RSV-neutralizing antibody, respiratory RSV load (qPCR), and F-gene-sequence-detection of PR was determined. Prophylactic RSV-IG [RI-002] or palivizumab was administered in a cotton-rat model infected with wild-type and PR-RSV. Lung RSV load and neutralizing antibody were measured.

RESULTS

As protective RI-001-neutralizing antibody titers waned in the infant, a subpopulation of PR-escape mutants were detected with a fatal RSV-burden in the lungs. In PR-RSV-infected cotton rats, prophylactic RI-002 reduced RSV-load in the lungs (2.45 vs 0.28 log10 PFU/g lung-tissue reduction, respectively, p < 0.05) and provided protective RSV-neutralizing antibody.

CONCLUSIONS

RSV-IG and ribavirin use in immunocompromised patients requires further study.

ASCENIV utilization in a primary immunodeficiency patient with recurrent viral infections

Primary immunodeficiency (PI) patients may still experience persistent viral and bacterial respiratory infections with ongoing treatments. We report a challenging case of a PI patient who experienced recurrent viral respiratory infections despite receiving standard immunoglobulin replacement therapy. The patient was subsequently managed with immune globulin intravenous, human-slra (ASCENIV™) that contains elevated antibodies against multiple respiratory pathogens. The patient demonstrated significant clinical improvement with a resolution of persistent and debilitating viral respiratory infections and associated sequela.

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

Introduction

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

Methods

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

Results

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

Discussion

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

Efficacy, safety and pharmacokinetics of a new 10% normal human immunoglobulin for intravenous infusion, BT595, in children and adults with primary immunodeficiency disease

BACKGROUND AND OBJECTIVES

To evaluate the efficacy, safety and pharmacokinetics of a new, highly purified 10% IVIg (BT595, Yimmugo®) administered in children and adults with Primary immunodeficiency diseases (PID).

MATERIALS AND METHODS

Prospective, uncontrolled, multicentre Phase III trial. Patients aged 2 to <76 years with PID were switched from their pre-trial IVIg replacement therapy to BT595. In all, 67 patients (49 adults, 18 children) received doses between 0.2 and 0.8 g/kg body weight for approximately 12 months at intervals of 3 or 4 weeks. Dosing and dosing intervals were based on each patient's pre-trial infusion schedule. The primary end point was the rate of acute serious bacterial infections (SBIs); secondary efficacy, safety and pharmacokinetic outcomes were also evaluated.

RESULTS

The primary efficacy end point was met, and the unadjusted SBI rate was 0.01 per subject-year (adjusted SBI rate 0.015 per subject-year, with an upper limit of the one-sided 99% confidence interval of 0.151). A single adult patient experienced one event classified as an SBI. All secondary end points, including those related to infections, supported the efficacy. Infusion rates were increased up to 8 ml/kg/h. Overall, 8% of infusions were associated with ≥1 infusional adverse event (AE) (start during or within 72 h post-infusion), comprising mainly headache (2.4%), fatigue (0.9%) and nausea (0.5%). There were no infusional AEs at infusion rates of >4.0 ml/kg/h, and only one patient required a single premedication. The observed patterns, severity and frequency of treatment-emergent adverse events are consistent with the established safety profile for IVIgs and did not show clinically relevant differences between all age groups.

CONCLUSION

BT595 is effective, safe and well tolerated for treating patients with PID.

Review of respiratory syncytial virus infection among older adults and transplant recipients

Respiratory syncytial virus (RSV) is a common cause of pulmonary infection among children and has been increasingly recognized as an important respiratory pathogen in older adults and immunocompromised hosts. Among older adults, RSV can lead to exacerbations of underlying lung and cardiac disease. It is also associated with significant morbidity and mortality in hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients and may be associated with acute rejection and chronic lung allograft dysfunction among lung transplant recipients (LTRs). Current treatment options for severe RSV disease are limited, and there is a paucity of guidance on RSV treatment among older adults. This narrative review provides a comprehensive overview of RSV disease in older adults, HSCT recipients, and SOT recipients. Nosocomial spread has been reported, thus highlighting the importance of infection prevention and control measures to prevent outbreaks. Antivirals, monoclonal antibodies for immunoprophylaxis, and vaccine development are underway; however, future research is still needed in these critical areas.

Efficacy, Safety and Tolerability of a New 10% Intravenous Immunoglobulin for the Treatment of Primary Immunodeficiencies

We report here the results of a phase 3 study to assess the efficacy, safety, and tolerability of GC5107, a new 10% liquid intravenous immunoglobulin (IVIG) in preventing serious bacterial infections in patients with primary immunodeficiency (ClinicalTrials.gov: NCT02783482). Over a 12-month study period, 49 patients aged 3 to 70 years with a confirmed diagnosis of primary immunodeficiency received GC5107 at doses ranging from 319 to 881 mg/kg body weight every 21 or 28 days, according to their previous IVIG maintenance therapy. A total of 667 infusions of GC5107 were administered comprising a total of 45.86 patient-years of treatment. A single acute serious bacterial infection occurred during the study, resulting in an incidence of 0.02 events per patient-year (upper 99% one-sided confidence interval limit: 0.21), meeting the prespecified primary efficacy endpoint. The mean incidence of infections other than acute serious bacterial infections was 2.9 infections per patient-year. Efficacy was also demonstrated by the low mean annualized rate of hospitalizations due to infection (0.1 day) and the mean annualized duration of hospitalizations (0.1 day). The mean rate of intravenous and oral antibiotic use was 0.1 day and 13.2 days, respectively. There was a mean of 7.1 days of missed work, school, or daycare days. The proportion of infusions with temporally associated adverse events (TAAEs) occurring during or within 72 hours after GC5107 infusion was 0.24 (upper 95% one-sided confidence interval limit: 0.31), meeting the pre-specified primary safety endpoint. Overall, 149 of 667 infusions (22%) were associated with TAAEs. The most common TAAE was headache, reported by 49% of patients. More than 98% (731/743) of all adverse events that occurred throughout the 12-month study period were mild or moderate. More than 98% of infusions were completed without discontinuation, interruption or rate reduction. There were no treatment-emergent serious adverse events related to GC5107 or study discontinuations due to an adverse event. Overall, pharmacokinetic parameters for GC5107 were within the range of those reported in studies of other marketed IVIG products. Results of the present study demonstrate that GC5107 is an effective, safe and well-tolerated treatment for patients with primary immunodeficiency.

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.

Development of Sentinel LN Imaging with a Combination of HAase Based on a Comprehensive Analysis of the Intra-lymphatic Kinetics of LPs

The sentinel lymph node (LN) is the first LN to which lymph fluid flows from tumor tissue. We identified the key parameters of liposomes (LPs) that affect their accumulation in regional (primary) LNs with minimum leakage to its connecting (secondary) LNs by a comprehensive analysis of the LN-to-LN trafficking of LPs with various surface charges and various sizes. We used a lymphatic flow-modified (LFM) mouse that allows for the chronological analysis of inguinal (primary) LN-to-axillary (secondary) LN at the body surface. As a result, the anionic medium-sized LPs (130 nm on average) exhibited the highest accumulation in the primary LNs. A mechanism-based analysis revealed that CD169-positive macrophages in LNs were the dominant cell population that captures anionic LPs. Sentinel LN imaging was also performed by the intratumoral injection of fluorescent medium-sized anionic LPs using a breast cancer orthotopic model. In comparison with the typically used contrast agent indocyanine green, the anionic LPs were detected in sentinel LNs with a high sensitivity. Additionally, the co-injection of hyaluronidase significantly improved the sensitivity of detection of the fluorescent LPs in sentinel LNs. In conclusion, medium-sized anionic LPs combined with hyaluronidase represents a potent strategy for investigating sentinel LNs.

Low immunoglobulin G4 subclass level is associated with recurrent wheezing in young children

Background

The most important infectious trigger of asthma is the virus and patients with immunoglobulin deficiencies are prone to recurrent respiratory infections.

Objective

We investigated the relationship between immunoglobulin G subclass and recurrent respiratory symptom exacerbation and explored possible therapeutic effects of intravenous immunoglobulin administration.

Methods

Twenty-eight infants less than 24 months old with 2 or more recurrent wheezing episodes (infantile wheezer group) and 29 asthmatic children aged 24 months to 15 years (bronchial asthma [B-asthma] group) visited our hospital from October 2010 to January 2018. Serum immunoglobulin G, A, M, E, G1, G2, G3, and G4 were measured in each group and compared. In both groups, serum immunoglobulin and symptoms were compared before and after intravenous immunoglobulin administration.

Results

The 2 study groups exhibited several statistically significant differences when comparing respiratory virus infection rate (p < 0.001), coinfection rate (p < 0.0001), most commonly found viral infection (human bocavirus vs. human rhinovirus), and immunoglobulin A (p < 0.001), E (p = 0.008), G2 (p < 0.001), and G4 (p = 0.011) levels. In the infantile wheezer group, there was an inverse correlation between immunoglobulin G4 levels and wheezing numbers (R = -0.5538, P = 0.0022). Both groups showed significant changes in immunoglobulin levels and respiratory symptom exacerbations (recurrent wheezing, shortness of breath, chest tightness, cough, and fever) over 1 year after intravenous immunoglobulin administration.

Conclusion

There was an association between recurrent wheezing and specific immunoglobulin G deficiencies. We suggest that intravenous immunoglobulin therapy significantly elevates specific immunoglobulin G levels though it lasts only for short term and might be associated with decreased respiratory symptoms. Therefore, low IgG4 levels among infants with recurrent wheezing may be indicative for intravenous immunoglobulin therapy.

A New Intravenous Immune Globulin: Novel or Not?

OBJECTIVE

To assess the clinical use and determine the place in therapy for immune globulin intravenous (IV), human-slra, a recently approved IV immune globulin for the treatment of primary immune deficiency diseases (PIDD).

DATA SOURCES

A PubMed and MEDLINE search (2010 to April 2020) was conducted for relevant articles. Data were also obtained from the package insert.

STUDY SELECTION AND DATA EXTRACTION

English language publications regarding the clinical efficacy and safety of immune globulin-slra were analyzed. Publications focused on use of immune globulin products were also included.

DATA SYNTHESIS

Immune globulin-slra is indicated for patients with PIDD and was specifically developed to include donor plasma with high respiratory syncytial virus (RSV) antibody titers. Efficacy was demonstrated through favorable incidence of infections and infection-related complications. Patients treated with immune globulin-slra had increases in anti-RSV neutralizing antibody titers compared with baseline. Adverse events occurred at rates similar to or less than other available immune globulin products.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review describes a new immune globulin product available for use in patients with PIDD. A novel approach to managing patients at risk of serious infections may be to utilize products with formulations proven to not only boost IgG levels, but also antibodies to specific pathogens.

CONCLUSIONS

The choice of which immune globulin product to select for a patient or formulary is complex. Each product is unique, and differences between products should be taken into consideration, along with cost and availability.

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.

Manufacturing process optimization of ADMA Biologics' intravenous immunoglobulin products, BIVIGAM® and ASCENIV™

Humoral immunodeficiency patients require immunoglobulin replacement to prevent infection. Traditional intravenous immunoglobulin manufacturing methods have had the potential for containing impurities caused by physical, chemical and thermal stressors that alter proteins. Two intravenous immunoglobulin products, BIVIGAM® and ASCENIV™, are manufactured by a modified Cohn-Oncley fractionation method followed by chromatographic purification. These products have undergone a systematic quality by design optimization to identify critical manufacturing processes to produce the highest quality product. This data driven, small-scale approach has led to manufacturing enhancements that have yielded consistent product improvements. The systematic approach to optimizing manufacturing has guided process changes, in-process, procedural and engineering controls that have reduced protein shearing and aggregation, and improved purity resulting in products with lot-to-lot consistency.

Overview of prevention and management of acute bronchiolitis due to respiratory syncytial virus

INTRODUCTION

Respiratory Syncytial Virus (RSV) is the most common cause of Acute Bronchiolitis (AVB) in infants. AVB causes significant morbidity and mortality worldwide, most deaths occurring in the developing world. AVB causes respiratory distress in infants, leading to respiratory failure in some cases. Disease is more severe in infants with risk factors, such as prematurity, chronic cardiac and lung disease and immunodeficiency. Areas covered: Despite major advances in supportive care in the developed world, which has led to a significant reduction in mortality, treatment remains symptomatic and supportive. No specific antiviral treatment has yet proven to be effective. Prevention of disease with monoclonal antibodies has proven to reduce illness severity in those with risk factors, however, this is prohibitively expensive, particularly for the developing world. Prospects for vaccine development are improving. However, because most disease is in young infants, maternal immunization is necessary. However, due to the transient nature of RSV immunity and the circulation of multiple subtypes, vaccines proven to be effective in adult challenge models have yet to be translated to protection in infants. Expert commentary: Despite advances in preventative treatments, adherence to evidence-based guidelines provides the best prospect for successful reduction in morbidity and mortality.

Application of Antibody-Mediated Therapy for Treatment and Prevention of Clostridium difficile Infection

Clostridium difficile causes antibiotic- and healthcare-associated diarrhea, which is characterized by a high mortality rate (5–15%) and high recurrence rate of 20% or more. Therapeutic alternatives to antibiotics are urgently needed to improve the overall cure rate. Among these, therapeutic antibodies have shown promising results in clinical studies. Herein, the authors review current monoclonal and polyclonal anti- C. difficile antibodies that have entered the clinical development stage, either for systemic administration or by the oral route. The antibodies can be applied as monotherapy or in combination with standard-of-care to treat an infection with C. difficile or to protect from a recurrence. Bezlotoxumab is the first antibody for secondary prevention of recurrence of C. difficile infection approved by the regulatory agencies in US and Europe. The human monoclonal antibody is administered systemically to patients receiving oral standard-of–care antibiotics. Other antibodies are currently in the clinical pipeline, and some are intended for oral use. They show a good safety profile, high efficacy and low production costs, and can be considered promising therapies of the future. The most promising orally administered drug candidate is a bovine antibody from hyperimmune colostral milk, which is in an advanced clinical development stage. Which antibody will enter the market is dependent on its bioavailability at the site of infection as well as its activity against C. difficile toxins, protection against colonization and possible action on spore formation. The antibody must demonstrate a clear benefit in comparison with other available treatment options to be considered for use by clinicians.

RI-002, an intravenous immunoglobulin containing high titer neutralizing antibody to RSV and other respiratory viruses for use in primary immunodeficiency disease and other immune compromised populations

Introduction: Novel immune globulin (IG) products (RI-002, RI-001) have been designed to provide protection against respiratory syncytial virus (RSV) mediated respiratory illness while at the same time meeting the manufacturing requirements established by FDA for antibody supplementation in immunocompromised subjects.

Areas covered: This review covers the manufacture and development of both RI-001 and RI-002, including the selection of plasma donors for IG preparation with high-titers of anti-RSV antibody, in vitro, and preclinical data in the cotton rat model S. hispidus, and clinical trials including Phase II and compassionate use studies of RI-001 and a multi-center, pivotal Phase III study of RI-002 in PIDD patients.

Expert commentary: The data demonstrate that RI-002 is efficacious in the prevention and treatment of RSV in preclinical normal and immune suppressed animal models and is safe and efficacious in the treatment of patients with various forms of primary immunodeficiency disease (PIDD). This product offers potential advantages over other available IG’s for prophylaxis in immunocompromised patients requiring polyclonal immunoglobulin supplementation because of its unique antibody composition. In addition to its enhanced neutralizing anti-RSV activity and its polyclonal IG composition, there is preclinical data to support the use of RI-002 for humoral protection against other respiratory pathogens.

Respiratory Syncytial Virus: Infection, Detection, and New Options for Prevention and Treatment

Respiratory syncytial virus (RSV) infection is a significant cause of hospitalization of children in North America and one of the leading causes of death of infants less than 1 year of age worldwide, second only to malaria. Despite its global impact on human health, there are relatively few therapeutic options available to prevent or treat RSV infection. Paradoxically, there is a very large volume of information that is constantly being refined on RSV replication, the mechanisms of RSV-induced pathology, and community transmission. Compounding the burden of acute RSV infections is the exacerbation of preexisting chronic airway diseases and the chronic sequelae of RSV infection. A mechanistic link is even starting to emerge between asthma and those who suffer severe RSV infection early in childhood. In this article, we discuss developments in the understanding of RSV replication, pathogenesis, diagnostics, and therapeutics. We attempt to reconcile the large body of information on RSV and why after many clinical trials there is still no efficacious RSV vaccine and few therapeutics.

Promising approaches for the treatment and prevention of viral respiratory illnesses

Viral respiratory tract infections are the most common human ailments, leading to enormous health and economic burden. Hundreds of viral species and subtypes have been associated with these conditions, with influenza viruses, respiratory syncytial virus, and rhinoviruses being the most frequent and with the highest burden. When considering prevention or treatment of viral respiratory tract infections, potential targets include the causative pathogens themselves but also the immune response, disease transmission, or even just the symptoms. Strategies targeting all these aspects are developing concurrently, and several novel and promising approaches are emerging. In this perspective we overview the entire range of options and highlight some of the most promising approaches, including new antiviral agents, symptomatic or immunomodulatory drugs, the re-emergence of natural remedies, and vaccines and public health policies toward prevention. Wide-scale prevention through immunization appears to be within reach for respiratory syncytial virus and promising for influenza virus, whereas additional effort is needed in regard to rhinovirus, as well as other respiratory tract viruses.

Compassionate use experience with high-titer respiratory syncytical virus (RSV) immunoglobulin in RSV-infected immunocompromised persons

BACKGROUND

Respiratory syncytial virus (RSV) may cause fatal lower respiratory tract infection (LRTI) in immunocompromised patients. Ribavirin with or without standard intravenous immunoglobulin (IVIG) is frequently given although efficacy is debated. Infusion of IVIG with high levels of neutralizing antibody against RSV may offer benefit in these patients.

METHODS

RI-001 contains standardized levels of high-titer anti-RSV neutralizing antibody and was provided for compassionate use to 15 patients with RSV LRTI who either failed conventional therapy or had significant risk of progression. Patients were treated on day 1 with RI-001 1500 mg/kg, followed 2 days later with 750 mg/kg. Pre- and post-infusion sera were measured for RSV neutralizing antibody. Patient data were analyzed for safety related to infusion of RI-001, and clinical outcomes.

RESULTS

Patients ranged in age from 2 months to 71 years and 80% had hematologic malignancy or were bone marrow or hematopoietic stem cell transplant recipients. Administration was well tolerated. Pre-infusion neutralizing titers ranged from 51 to 1765 geometric mean titer (mean 646±519) and all patients demonstrated at least a 4-fold rise (mean 6410±4470) 5-10 days post infusion. Eleven of 15 improved and were discharged from the hospital. Days from positive RSV test to RI-001 treatment was shorter in survivors compared to non-survivors (4.4±2.8 vs. 20.3±21.0 days, P=.02).

CONCLUSION

Administration of RI-001 was well tolerated and resulted in significant increases in serum neutralizing antibody titers to RSV. Our data suggest that early identification of RSV and treatment with RI-001 may offer benefit.