Augmentation therapy with alpha1-antitrypsin: patterns of use and adverse events

Nine controversial questions about augmentation therapy for alpha-1 antitrypsin deficiency: a viewpoint

Augmentation therapy with intravenous alpha-1 antitrypsin is the only specific treatment for alpha-1 antitrypsin deficiency (AATD)-associated emphysema. This treatment has been available and remained basically unchanged for more than 35 years, but many questions persist regarding its indications, regimen of administration and efficacy. Because AATD is a rare disease, it has not been possible to conduct randomised, placebo-controlled trials that are adequately powered for the usual outcomes analysed in non-AATD-related COPD, such as lung function decline, exacerbations, symptoms or quality of life. New outcomes such as lung densitometry measured by computed tomography are more sensitive for identifying emphysema progression but are not widely accepted by regulatory agencies. In addition, clinical manifestations, severity and the natural history of lung disease associated with AATD are very heterogeneous, which means that individual prediction of prognosis is challenging. Therefore, the indication for augmentation is sometimes a dilemma between initiating treatment in individuals who may not develop significant lung disease or in whom disease will not progress and delaying it in patients who will otherwise rapidly and irreversibly progress.Other areas of debate are the possible indication for augmentation in patients with severe AATD and respiratory diseases other than emphysema, such as bronchiectasis or asthma, and the use of therapy after lung transplant in AATD patients. All these uncertainties imply that the indication for treatment must be personalised in expert reference centres after in-depth discussion of the pros and cons of augmentation with the patient.

Utility of the Serum Protein Electrophoresis in the Opportunistic Screening for the Deficiency of Alpha-1 Antitrypsin

BACKGROUND

A deficiency in alpha-1 antitrypsin (AAT1) is a rare disorder that represents a significant health threat and early diagnostic priority issue. We investigated the usefulness of the serum protein electrophoresis (SPE) as an opportunistic screening tool for AAT1 deficiency.

METHODS

For 6 months, all SPE carried out for any reasons were evaluated in our center. In those with less than 3% of alpha-1 globulins, AAT1 concentrations were studied. The SERPINA1 gene was subsequently sequenced in those patients displaying concentrations below 100 mg/dL.

RESULTS

Out of the total, 14 patients (0.3%) were identified with low AAT1 concentrations, with 11 of them agreeing to enter the study. Of those, mutations in the SERPINA1 gene were discovered in 10 patients (91%). Heterozygous mutations were detected in seven patients; three had the c.1096G>A mutation (p.Glu366Lys; Pi*Z), two had the c.863A>T mutation (p.Glu288Val; Pi*S), one had the c.221_223delTCT mutation (p.Phe76del; Pi*Malton), and the last one had the c.1066G>A (p.Ala356Thr) mutation, which was not previously described. Finally, one patient had the c.863A>T mutation in homozygosis, whereas two double heterozygous patients c.863A>T/c.1096G>A were detected.

CONCLUSIONS

An altered result in the concentration of AAT1 anticipates a mutation in the SERPINA1 gene in a manner close to 91%. The relationship between a decrease in the alpha-1 globulin band of the SPE and an alteration in the AAT1 concentration is direct in basal states of health. The SPE is presented as a highly sensitive test for opportunistic screening of AAT1 deficiency.

A randomized, double-blind, placebo-controlled trial of intravenous alpha-1 antitrypsin for acute respiratory distress syndrome secondary to COVID-19

Background

Patients with severe coronavirus disease 2019 (COVID-19) develop a febrile pro-inflammatory cytokinemia with accelerated progression to acute respiratory distress syndrome (ARDS). Here we report the results of a phase 2, multicenter, randomized, double-blind, placebo-controlled trial of intravenous (IV) plasma-purified alpha-1 antitrypsin (AAT) for moderate to severe ARDS secondary to COVID-19 (EudraCT 2020-001391-15).

Methods

Patients (n = 36) were randomized to receive weekly placebo, weekly AAT (Prolastin, Grifols, S.A.; 120 mg/kg), or AAT once followed by weekly placebo. The primary endpoint was the change in plasma interleukin (IL)-6 concentration at 1 week. In addition to assessing safety and tolerability, changes in plasma levels of IL-1β, IL-8, IL-10, and soluble tumor necrosis factor receptor 1 (sTNFR1) and clinical outcomes were assessed as secondary endpoints.

Findings

Treatment with IV AAT resulted in decreased inflammation and was safe and well tolerated. The study met its primary endpoint, with decreased circulating IL-6 concentrations at 1 week in the treatment group. This was in contrast to the placebo group, where IL-6 was increased. Similarly, plasma sTNFR1 was substantially decreased in the treatment group while remaining unchanged in patients receiving placebo. IV AAT did not definitively reduce levels of IL-1β, IL-8, and IL-10. No difference in mortality or ventilator-free days was observed between groups, although a trend toward decreased time on ventilator was observed in AAT-treated patients.

Conclusions

In patients with COVID-19 and moderate to severe ARDS, treatment with IV AAT was safe, feasible, and biochemically efficacious. The data support progression to a phase 3 trial and prompt further investigation of AAT as an anti-inflammatory therapeutic.

Funding

ECSA-2020-009; Elaine Galwey Research Bursary.

Management of lung disease in alpha-1 antitrypsin deficiency: what we do and what we do not know

Management of lung disease in patients with alpha-1 antitrypsin deficiency (AATD) includes both non-pharmacological and pharmacological approaches. Lifestyle changes with avoidance of environmental pollutants, including tobacco smoke, improving exercise levels and nutritional status, all encompassed under a disease management program, are crucial pillars of AATD management. Non-pharmacological therapies follow conventional treatment guidelines for chronic obstructive pulmonary disease. Specific pharmacological treatment consists of administering exogenous alpha-1 antitrypsin (AAT) protein intravenously (augmentation therapy). This intervention raises AAT levels in serum and lung epithelial lining fluid, increases anti-elastase capacity, and decreases several inflammatory mediators in the lung. Radiologically, augmentation therapy reduces lung density loss over time, thus delaying disease progression. The effect of augmentation therapy on other lung-related outcomes, such as exacerbation frequency/length, quality of life, lung function decline, and mortality, are less clear and questions regarding dose optimization or route of administration are still debatable. This review discusses the rationale and available evidence for these interventions in AATD.

Alpha-1 Antitrypsin Deficiency: Home Therapy

While available in only a few countries, home therapy is a possible strategy for the treatment of alpha-1 antitrypsin deficiency. We want to describe our experience in the management of human alpha-1 antitrypsin using home care intravenous augmentation therapy during this emergency period caused by SARS-CoV2 infection. We assessed the safety of the home treatment and the quality of life of patients enrolled in the program.

Implications of a Change of Paradigm in Alpha1 Antitrypsin Deficiency Augmentation Therapy: From Biochemical to Clinical Efficacy

Ever since the first studies, restoring proteinase imbalance in the lung has traditionally been considered as the main goal of alpha1 antitrypsin (AAT) replacement therapy. This strategy was therefore based on ensuring biochemical efficacy, identifying a protection threshold, and evaluating different dosage regimens. Subsequently, the publication of the results of the main clinical trials showing a decrease in the progression of pulmonary emphysema has led to a debate over a possible change in the main objective of treatment, from biochemical efficacy to clinical efficacy in terms of lung densitometry deterioration prevention. This new paradigm has produced a series controversies and unanswered questions which face clinicians managing AAT deficiency. In this review, the concepts that led to the approval of AAT replacement therapy are reviewed and discussed under a new prism of achieving clinical efficacy, with the reduction of lung deterioration as the main objective. Here, we propose the use of current knowledge and clinical experience to face existing challenges in different clinical scenarios, in order to help clinicians in decision-making, increase interest in the disease, and stimulate research in this field.

Portuguese consensus document for the management of alpha-1-antitrypsin deficiency

Alpha-1-antitrypsin deficiency (AATD) is a genetic autosomal codominant disorder caused by mutations in SERPINA1 gene. It is one of the most prevalent genetic disorders, although it remains underdiagnosed. Whereas at international level there are several areas of consensus on this disorder, in Portugal, inter-hospital heterogeneity in clinical practice and resources available have been adding difficulties in reaching a diagnosis and in making therapeutic decisions in this group of patients. This raised a need to draft a document expressing a national consensus for AATD. To this end, a group of experts in this field was created within the Portuguese Pulmonology Society - Study group on AATD, in order to elaborate the current manuscript. The authors reviewed the existing literature and provide here general guidance and extensive recommendations for the diagnosis and management of AATD that can be adopted by Portuguese clinicians from different areas of Medicine. This article is part of a supplement entitled "Portuguese consensus document for the management of alpha-1-antitrypsin deficiency" which is sponsored by Sociedade Portuguesa de Pneumologia.

Safety and pharmacokinetics of Alpha-1 MP (Prolastin®-C) in Japanese patients with alpha1-antitrypsin (AAT) deficiency

BACKGROUND

Alpha₁-Proteinase Inhibitor, Modified Process (Alpha-1 MP) is used for augmentation therapy in alpha1-antitrypsin deficiency (AATD), an extremely rare disease in Japan. Weekly doses of 60 mg/kg Alpha-1 MP have been shown to be safe and well tolerated in non-Japanese subjects, but the safety and pharmacokinetics (PK) have not been evaluated in Japanese subjects. The objectives of this study were to evaluate the safety and PK of 60 mg/kg Alpha-1 MP administered by weekly IV infusions over 8 weeks in Japanese subjects with AATD.

METHODS

This was a multicenter, open-label trial in Japanese adults aged ≥20 years with AATD. Samples for evaluation of serum alpha₁-PI concentration and PK parameters were collected at 10 time points until the seventh day after the last dose at Week 8: immediately before dosing, immediately after dosing (time 0), and 0.25, 2, 4, 8, 24, 48, 120, and 168 hours after dosing.

RESULTS

Four subjects were analyzed. The median t_max was 0.534 h. Mean ± SD values for t_½, C_max, and AUC_0-7days were 150.4 ± 36.18 h, 174.2 ± 30.51 mg/dL, and 14,913.2 ± 1633.45 mg*h/dL, respectively. Mean trough concentration at week 8 was 55.4 ± 7.23 mg/dL. Alpha-1 MP therapy was safe, with no serious adverse events or deaths reported. Two treatment-emergent adverse events of fatigue in one subject were considered to be possibly related.

CONCLUSIONS

The PK and safety of Alpha-1 MP in Japanese subjects with AATD were consistent with the Alpha-1 MP profile in non-Japanese subjects (ClinicalTrials.gov: NCT02870309; JAPIC CTI: JapicCTI-163160).

Impact of a Health Management Program on Healthcare Outcomes among Patients on Augmentation Therapy for Alpha 1-Antitrypsin Deficiency: An Insurance Claims Analysis

Introduction

Alpha 1-antitrypsin deficiency (AATD) is a genetic disorder which reduces serum alpha 1-antitrypsin (AAT or alpha1-proteinase inhibitor, A1PI) and increases the risk of chronic obstructive pulmonary disease (COPD). Management strategies include intravenous A1PI augmentation, and, in some cases, a health management program (Prolastin Direct^®; PD).

Objectives

This study compared clinical and economic outcomes between patients with and without PD program participation.

Methods

This retrospective study included commercial and Medicare Advantage health insurance plan members with ≥ 1 claim with diagnosis codes for COPD and ≥ 1 medical or pharmacy claim including A1PI (on index date). Outcomes were compared between patients receiving only Prolastin^® or Prolastin^®-C (PD cohort) and patients who received a different brand without PD (Comparator cohort). Demographic and clinical characteristics were captured during 6 months pre-index. Post-index exacerbation episodes and healthcare utilization and costs were compared between cohorts.

Results

The study sample comprised 445 patients (n = 213 in PD cohort; n = 232 in Comparator cohort), with a mean age 55.5 years, 50.8% male, and 78.9% commercially insured. The average follow-up was 822 days (2.25 years), and the average time on A1PI was 747 days (2.04 years). Few differences were observed in demographic or clinical characteristics. Adjusting for differences in patient characteristics, the rate of severe exacerbation episodes was reduced by 36.1% in the PD cohort. Adjusted total annual all-cause costs were 11.4% lower, and adjusted mean respiratory-related costs were 10.6% lower in the PD cohort than the Comparator cohort. Annual savings in all-cause total costs in the PD cohort relative to the Comparator cohort was US$25,529 per patient, largely due to significantly fewer and shorter hospitalizations.

Conclusions

These results suggest that comprehensive health management services may improve both clinical and economic outcomes among patients with COPD and AATD who receive augmentation therapy.

Funding

Grifols Shared Services of North America, Inc.

Electronic supplementary material

The online version of this article (10.1007/s12325-018-0690-4) contains supplementary material, which is available to authorized users.

European Respiratory Society statement: diagnosis and treatment of pulmonary disease in α1-antitrypsin deficiency

α1-antitrypsin deficiency (AATD) is the most common hereditary disorder in adults. It is associated with an increased risk of developing pulmonary emphysema and liver disease. The pulmonary emphysema in AATD is strongly linked to smoking, but even a proportion of never-smokers develop progressive lung disease. A large proportion of individuals affected remain undiagnosed and therefore without access to appropriate care and treatment.

The most recent international statement on AATD was published by the American Thoracic Society and the European Respiratory Society in 2003. Since then there has been a continuous development of novel, more accurate and less expensive genetic diagnostic methods. Furthermore, new outcome parameters have been developed and validated for use in clinical trials and a new series of observational and randomised clinical trials have provided more evidence concerning the efficacy and safety of augmentation therapy, the only specific treatment available for the pulmonary disease associated with AATD.

As AATD is a rare disease, it is crucial to organise national and international registries and collect information prospectively about the natural history of the disease. Management of AATD patients must be supervised by national or regional expert centres and inequalities in access to therapies across Europe should be addressed.

Clinical utility of alpha-1 proteinase inhibitor in the management of adult patients with severe alpha-1 antitrypsin deficiency: a review of the current literature

Alpha-1 antitrypsin (AAT) functions primarily to inhibit neutrophil elastase, and its deficiency predisposes individuals to the development of chronic obstructive pulmonary disease (COPD). The putative protective serum concentration is generally considered to be above a threshold of 11 μM/L, and therapeutic augmentation of AAT above this value is believed to retard the progression of emphysema. Several AAT preparations, all derived from human donor plasma, have been commercialized since approval by the US Food and Drug Administration (FDA) in 1987. Biochemical efficacy has been demonstrated by augmentation of pulmonary antiprotease activity, but demonstration of clinical efficacy in randomized, placebo-controlled trials has been hampered by the practical difficulties of performing conventional studies in a rare disease with a relatively long natural history. Computed tomography has been applied to measure lung density as a more specific and sensitive surrogate outcome measure of emphysema than physiologic indices, such as forced expiratory volume in 1 second, and studies consistently show a therapeutic reduction in the rate of lung density decline. However, convincing evidence of benefit using traditional clinical measures remains elusive. Intravenous administration of AAT at a dose of 60 mg/kg/week is the commonest regime in use and has well-documented safety and tolerability. International and national guidelines on the management of AAT deficiency recommend intravenous augmentation therapy to supplement optimized usual COPD treatment in patients with severe deficiency and evidence of lung function impairment.

Treatment of lung disease in alpha-1 antitrypsin deficiency: a systematic review

BACKGROUND

Alpha-1 antitrypsin deficiency (AATD) is a rare genetic condition predisposing individuals to chronic obstructive pulmonary disease (COPD). The treatment is generally extrapolated from COPD unrelated to AATD; however, most COPD trials exclude AATD patients; thus, this study sought to systematically review AATD-specific literature to assist evidence-based patient management.

METHODS

Standard review methodology was used with meta-analysis and narrative synthesis (PROSPERO-CRD42015019354). Eligible studies were those of any treatment used in severe AATD. Randomized controlled trials (RCTs) were the primary focus; however, case series and uncontrolled studies were eligible. All studies had ≥10 participants receiving treatment or usual care, with baseline and follow-up data (>3 months). Risk of bias was assessed appropriately according to study methodology.

RESULTS

In all, 7,296 studies were retrieved from searches; 52 trials with 5,632 participants met the inclusion criteria, of which 26 studies involved alpha-1 antitrypsin augmentation and 17 concerned surgical treatments (largely transplantation). Studies were grouped into four management themes: COPD medical, COPD surgical, AATD specific, and other treatments. Computed tomography (CT) density, forced expiratory volume in 1 s, diffusing capacity of the lungs for carbon monoxide, health status, and exacerbation rates were frequently used as outcomes. Meta-analyses were only possible for RCTs of intravenous augmentation, which slowed progression of emphysema measured by CT density change, 0.79 g/L/year versus placebo (P=0.002), and associated with a small increase in exacerbations 0.29/year (P=0.02). Mortality following lung transplant was comparable between AATD- and non-AATD-related COPD. Surgical reduction of lung volume demonstrated inferior outcomes compared with non-AATD-related emphysema.

CONCLUSION

Intravenous augmentation remains the only disease-specific therapy in AATD and there is evidence that this slows decline in emphysema determined by CT density. There is paucity of data around other treatments in AATD. Treatments for usual COPD may not be as efficacious in AATD, and further studies may be required for this disease group.

Therapeutics: Alpha-1 Antitrypsin Augmentation Therapy

Subjects with alpha-1 antitrypsin deficiency who develop pulmonary disease are managed following general treatment guidelines, including disease management interventions. In addition, administration of intravenous infusions of alpha-1 proteinase inhibitor (augmentation therapy) at regular schedules is a specific therapy for individuals with AATD with pulmonary involvement.This chapter summarizes the manufacturing differences of commercially available formulations and the available evidence of the effects of augmentation therapy. Biologically, there is clear evidence of in vivo local antiprotease effects in the lung and systemic immunomodulatory effects. Clinically, there is cumulative evidence of slowing lung function decline and emphysema progression. The optimal dose of augmentation therapy is being revised as well as more individualized assessment of who needs this therapy.

α1-Antitrypsin reduces rhinovirus infection in primary human airway epithelial cells exposed to cigarette smoke

Human rhinovirus (HRV) infections target airway epithelium and are the leading cause of acute exacerbations of COPD. Cigarette smoke (CS) increases the severity of viral infections, but there is no effective therapy for HRV infection. We determined whether α1-antitrypsin (A1AT) reduces HRV-16 infection in CS-exposed primary human airway epithelial cells. Brushed bronchial epithelial cells from normal subjects and patients diagnosed with COPD were cultured at air–liquid interface to induce mucociliary differentiation. These cells were treated with A1AT or bovine serum albumin for 2 hours and then exposed to air or whole cigarette smoke (WCS) with or without HRV-16 (5×10⁴ 50% Tissue Culture Infective Dose [TCID₅₀]/transwell) infection for 24 hours. WCS exposure significantly increased viral load by an average of fivefold and decreased the expression of antiviral genes interferon-λ1, OAS1, and MX1. When A1AT was added to WCS-exposed cells, viral load significantly decreased by an average of 29-fold. HRV-16 infection significantly increased HRV-16 receptor intercellular adhesion molecule-1 messenger RNA expression in air-exposed cells, which was decreased by A1AT. A1AT-mediated reduction of viral load was not accompanied by increased epithelial antiviral gene expression or by inhibiting the activity of 3C protease involved in viral replication or maturation. Our findings demonstrate that A1AT treatment prevents a WCS-induced increase in viral load and for the first time suggest a therapeutic effect of A1AT on HRV infection.

Inhaled alpha1-proteinase inhibitor therapy in patients with cystic fibrosis

BACKGROUND

Inhaled alpha1-proteinase inhibitor (PI) is known to reduce neutrophil elastase burden in some patients with CF. This phase 2a study was designed to test inhaled Alpha-1 HC, a new aerosolized alpha1-PI formulation, in CF patients.

METHODS

We performed a randomized, double-blind, placebo-controlled study and evaluated the safety of 100 or 200mg of inhaled Alpha-1 HC once daily for 3 weeks in subjects with CF. Thirty adult subjects were randomized in a 2:1 ratio to receive Alpha-1 HC or placebo.

RESULTS

Drug delivery was confirmed by a dose-dependent increase in the sputum alpha1-PI. Seven (20.0%) of the 35 adverse events in the 100-mg dose group, 3 (13.0%) of 23 in the 200-mg dose group, and 4 (14.3%) of 28 in the placebo group were drug-related in these subjects. One serious adverse event occurred in 1 subject within each group.

CONCLUSIONS

Alpha-1 HC inhalation was safe and well tolerated.

Augmentation therapy of alpha-1 antitrypsin deficiency associated emphysema

INTRODUCTION

Alpha-1 antitrypsin, secreted by the liver, inhibits neutrophil elastase. Its deficiency favours the development of emphysema. Restoring a "protective" serum level in deficient patients should make it possible to inhibit the development of emphysema.

STATE OF THE ART

Human plasma-derived alpha-1 antitrypsin is a blood-derived drug sold in France under the name Alfalastin(®). The recommended posology is an I.V. administration of 60 mg/kg once a week. Human plasma-derived alpha-1 antitrypsin restores anti-elastase protection in the lower lung and prevents experimental emphysema induced by the elastasis of human neutrophils in hamster. The low number of patients with alpha-1 antitrypsin deficiency is one of the difficulties to perform sufficiently powerful randomised studies. However, randomised studies have reported the efficacy of human plasma-derived alpha-1 antitrypsin perfusions on mortality, FEV1 decline and the frequency of exacerbations. Randomised control trials have demonstrated the efficacy of human plasma-derived alpha-1 antitrypsin perfusions on the loss of lung density assessed by CT scan.

CONCLUSION

Augmentation therapy is simple in its conception and implementation, but it is expensive. However, there are currently no other solutions.

Indications for active case searches and intravenous alpha-1 antitrypsin treatment for patients with alpha-1 antitrypsin deficiency chronic pulmonary obstructive disease: an update

The effect of hereditary alpha-1 antitrypsin (AAT) deficiency can manifest clinically in the form of chronic obstructive pulmonary disease (COPD). AAT deficiency (AATD) is defined as a serum concentration lower than 35% of the expected mean value or 50 mg/dl (determined by nephelometry). It is associated in over 95% of cases with Pi*ZZ genotypes, and much less frequently with other genotypes resulting from combinations of Z, S, rare and null alleles. A systematic qualitative review was made of 107 articles, focusing mainly on an active search for AATD in COPD patients and intravenous (iv) treatment with AAT. On the basis of this review, the consultant committee of the Spanish Registry of Patients with AATD recommends that all COPD patients be screened for AATD with the determination of AAT serum concentrations, and when these are low, the evaluation must be completed with phenotyping and, on occasions, genotyping. Patients with severe AATD COPD should receive the pharmacological and non-pharmacological treatment recommended in the COPD guidelines. There is enough evidence from large observational studies and randomized placebo-controlled clinical trials to show that the administration of iv AAT reduces mortality and slows the progression of emphysema, hence its indication in selected cases that meet the inclusion criteria stipulated in international guidelines. The administration of periodic infusions of AAT is the only specific treatment for delaying the progression of emphysema associated with AATD.

Alpha-1 proteinase inhibitors for the treatment of alpha-1 antitrypsin deficiency: safety, tolerability, and patient outcomes

Alpha-1 antitrypsin (AAT) deficiency remains an underrecognized genetic disease with predominantly pulmonary and hepatic manifestations. AAT is derived primarily from hepatocytes; however, macrophages and neutrophils are secondary sources. As the natural physiological inhibitor of several proteases, most importantly neutrophil elastase (NE), it plays a key role in maintaining pulmonary protease–antiprotease balance. In deficient states, unrestrained NE activity promotes damage to the lung matrix, causing structural defects and impairing host defenses. The commonest form of AAT deficiency results in a mutated Z AAT that is abnormally folded, polymerized, and aggregated in the liver. Consequently, systemic levels are lower, resulting in diminished pulmonary concentrations. Hepatic disease occurs due to liver aggregation of the protein, while lung destruction ensues from unopposed protease-mediated damage. In this review, we will discuss AAT deficiency, its clinical manifestations, and augmentation therapy. We will address the safety and tolerability profiles of AAT replacement in the context of patient outcomes and cost-effectiveness and outline future directions for work in this field.

Role of alpha-1 antitrypsin in human health and disease

Alpha-1 antitrypsin (AAT) deficiency is an under-recognized hereditary disorder associated with the premature onset of chronic obstructive pulmonary disease, liver cirrhosis in children and adults, and less frequently, relapsing panniculitis, systemic vasculitis and other inflammatory, autoimmune and neoplastic diseases. Severe AAT deficiency mainly affects Caucasian individuals and has its highest prevalence (1 : 2000-1 : 5000 individuals) in Northern, Western and Central Europe. In the USA and Canada, the prevalence is 1: 5000-10 000. Prevalence is five times lower in Latin American countries and is rare or nonexistent in African and Asian individuals. The key to successful diagnosis is by measuring serum AAT, followed by the determination of the phenotype or genotype if low concentrations are found. Case detection allows implementation of genetic counselling and, in selected cases, the application of augmentation therapy. Over the past decade, it has been demonstrated that AAT is a broad-spectrum anti-inflammatory, immunomodulatory, anti-infective and tissue-repair molecule. These new capacities are promoting an increasing number of clinical studies, new pharmacological formulations, new patent applications and the search for alternative sources of AAT (including transgenic and recombinant AAT) to meet the expected demand for treating a large number of diseases, inside and outside the context of AAT deficiency.

α1 Antitrypsin deficiency: current best practice in testing and augmentation therapy

α1 Antitrypsin deficiency (AATD) increases the risk of chronic obstructive pulmonary disease (COPD), liver disease and other conditions. Although it is not a rare disease, it is a condition rarely diagnosed because of unawareness by most healthcare providers who manage subjects at risk. Testing recommendations have been published and strongly suggest testing all subjects with confirmed COPD, cryptogenic liver cirrhosis, subjects with incompletely reversible airflow obstruction and siblings of affected individuals. Testing strategies usually imply a combination of measures of α1 antitrypsin (AAT) levels, phenotyping and genotyping, techniques that have been facilitated for in-office use by development of testing kits using dried blood spots. Early detection of subjects is crucial to apply effective preventive measures and early institution of therapy. The only specific Food and Drug Administration - approved therapy for this condition is lifelong weekly intravenous AAT replacement (augmentation therapy). Observational studies strongly suggest a beneficial effect of augmentation therapy in slowing lung function decline and randomized trials suggest a beneficial effect in slowing the progression of emphysema over time as measured by computed tomography. In addition, augmentation therapy has been shown to modulate systemic inflammatory responses and affect markers of elastin degradation. As new markers of disease progression are discovered, new doses of AAT replacement are tested and sub-phenotypes of disease are described, treatment recommendations are likely to change towards a more individualized therapeutic approach.

Biochemical efficacy and safety of a new, ready-to-use, liquid alpha-1-proteinase inhibitor, GLASSIA (alpha1-proteinase inhibitor (human), intravenous)

Maintaining serum levels of alpha-1-proteinase inhibitor (A1PI) >11 μM by augmentation with plasma-derived human A1PI is currently the only specific therapy available to treat patients with the genetic deficiency of A1PI. In this study, a new, high-purity (≥90% A1PI in monomeric form), ready-to-use, liquid formulation of A1PI-GLASSIA (Kamada, Ness Ziona, Israel) was compared to PROLASTINÆ (Talecris, Research Triangle Park, NC, now Grifols), both commercially available, FDA-approved products. This multicenter, double-blind, randomized controlled trial with partial cross-over was designed to test the non-inferiority and safety of GLASSIA compared to PROLASTIN, assessing both antigenic and functional A1PI trough levels in subject serum. Non-inferiority of GLASSIA to PROLASTIN was demonstrated by remaining within the lower bounds of the confidence intervals (≤3 μM) for both antigenic and functional A1PI. The study concluded that GLASSIA, a new liquid, ready to use, formulation of A1PI, was not inferior to PROLASTIN and it was well tolerated with a safety profile comparable to PROLASTIN.

Aspiration, localized pulmonary inflammation, and predictors of early-onset bronchiolitis obliterans syndrome after lung transplantation

BACKGROUND

We hypothesized that immune mediator concentrations in the bronchoalveolar fluid (BALF) are predictive of bronchiolitis obliterans syndrome (BOS) and demonstrate specific patterns of dysregulation, depending on the presence of acute cellular rejection, BOS, aspiration, and timing of lung transplantation.

STUDY DESIGN

We prospectively collected 257 BALF samples from 105 lung transplant recipients. The BALF samples were assessed for absolute and differential white blood cell counts and 34 proteins implicated in pulmonary immunity, inflammation, fibrosis, and aspiration.

RESULTS

There were elevated BALF concentrations of interleukin (IL)-15, IL-17, basic fibroblast growth factor, tumor necrosis factor-α, and myeloperoxidase, and reduced concentrations of α1-antitrypsin, which were predictive of early-onset BOS. Patients with BOS had an increased percentage of BALF lymphocytes and neutrophils, with a reduced percentage of macrophages (p < 0.05). The BALF concentrations of IL-1β; IL-8; interferon-γ-induced protein 10; regulated upon activation, normal T-cell expressed and secreted; neutrophil elastase; and pepsin were higher in patients with BOS (p < 0.05). Among those with BOS, BALF concentrations of IL-1RA; IL-8; eotaxin; interferon-γ-induced protein 10; regulated upon activation, normal T-cell expressed and secreted; myeloperoxidase; and neutrophil elastase were positively correlated with time since transplantation (p < 0.01). Those with worse grades of acute cellular rejection had an increased percentage of lymphocytes in their BALF (p < 0.0001) and reduced BALF concentrations of IL-1β, IL-7, IL-9, IL-12, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, interferon-γ, and vascular endothelial growth factor (p ≤ 0.001). Patients with aspiration based on detectable pepsin had increased percentage of neutrophils (p < 0.001) and reduced BALF concentrations of IL-12 (p < 0.001).

CONCLUSIONS

The BALF levels of IL-15, IL-17, basic fibroblast growth factor, tumor necrosis factor-α, myeloperoxidase, and α1-antitrypsin at 6 to 12 months after lung transplantation are predictive of early-onset BOS, and those with BOS and aspiration have an augmented chemotactic and inflammatory balance of pulmonary leukocytes and immune mediators. These data justify the surgical prevention of aspiration and argue for the refinement of antirejection regimens.

Scratching the surface of allergic transfusion reactions

Allergic transfusion reactions (ATRs) are a spectrum of hypersensitivity reactions that are the most common adverse reaction to platelets and plasma, occurring in up to 2% of transfusions. Despite the ubiquity of these reactions, little is known about their mechanism. In a small subset of severe reactions, specific antibody has been implicated as causal, although this mechanism does not explain all ATRs. Evidence suggests that donor, product, and recipient factors are involved, and it is possible that many ATRs are multifactorial. Further understanding of the mechanisms of ATRs is necessary so that rationally designed and cost-effective prevention measures can be developed.

Alpha-1 antitrypsin deficiency targeted testing and augmentation therapy: a Canadian Thoracic Society clinical practice guideline

Alpha-1 antitrypsin (A1AT) functions primarily to inhibit neutrophil elastase, and deficiency predisposes individuals to the development of chronic obstructive pulmonary disease (COPD). Severe A1AT deficiency occurs in one in 5000 to one in 5500 of the North American population. While the exact prevalence of A1AT deficiency in patients with diagnosed COPD is not known, results from small studies provide estimates of 1% to 5%. The present document updates a previous Canadian Thoracic Society position statement from 2001, and was initiated because of lack of consensus and understanding of appropriate patients suitable for targeted testing for A1AT deficiency, and for the use of A1AT augmentation therapy. Using revised guideline development methodology, the present clinical practice guideline document systematically reviews the published literature and provides an evidence-based update. The evidence supports the practice that targeted testing for A1AT deficiency be considered in individuals with COPD diagnosed before 65 years of age or with a smoking history of <20 pack years. The evidence also supports consideration of A1AT augmentation therapy in nonsmoking or exsmoking patients with COPD (forced expiratory volume in 1 s of 25% to 80% predicted) attributable to emphysema and documented A1AT deficiency (level ≤11 µmol⁄L) who are receiving optimal pharmacological and nonpharmacological therapies (including comprehensive case management and pulmonary rehabilitation) because of benefits in computed tomography scan lung density and mortality.

α1-Antitrypsin in fibromyalgia: results of a randomized, placebo-controlled, double-blind and crossover pilot trial

OBJECTIVE

To assess clinical effect of a human plasma-derived alpha-1 antitrypsin (AAT) concentrate in reducing pain severity of patients with fibromyalgia (FM).

METHODS

Thirteen subjects with FM completed a randomized, double-blind, placebo-controlled, crossover study which consisted of 9 weeks trial of AAT or placebo with a washout period of 6 weeks. Primary efficacy endpoint was change on pain severity score, assessed by a daily visual analogue scale (VAS) for pain. Other outcome measures included a tender point score, the Fibromyalgia Impact Questionnaire, (FIQ), the Medical Outcomes Study Short Form 36 (SF-36), the Health Assessment Questionnaire Disability Index (HAQ-DI), the Hospital Anxiety and Depression Scale (HADS) and tiredness score evaluated by VAS.

RESULTS

No statistically significant differences were observed in either pain severity or other secondary outcome measures in either of the treatment groups, or between treatment groups in either of the treatment periods. No carryover or order of intervention effect was observed from one treatment to the other. Both investigational interventions were generally well tolerated, and vital signs during the drug infusions were within the respective normal ranges.

CONCLUSION

Treatment with a human plasma-derived AAT concentrate did not demonstrate significant improvement over placebo on reducing pain severity and other symptoms of FM. Further research should examine other FM subpopulations and drug doses.

A review of augmentation therapy for alpha-1 antitrypsin deficiency

INTRODUCTION

Alpha-1 antitrypsin deficiency (AATD) is a relatively common, but under-recognized condition which manifests commonly with liver cirrhosis and emphysema. Specific therapy for lung-affected individuals with AATD is augmentation therapy, which consists of intravenous infusion of purified human plasma-derived alpha-1 antitrypsin (AAT). Augmentation therapy was first approved by the United States Food and Drug Administration (FDA) in 1987 for emphysema associated with severe AATD and today, six augmentation therapy preparations, all of which derive from pooled human plasma, have received FDA approval.

AREAS COVERED

This paper reviews augmentation therapy for AATD, including the various available commercial preparations, their processing and biochemical differences, evidence regarding biochemical and clinical efficacy, patterns of clinical use, adverse effect profiles, cost-effectiveness and potential uses in conditions other than emphysema associated with AATD. Novel and emerging strategies for treating AATD are briefly discussed next, including alternative dosing and administration strategies, recombinant preparations, small molecule inhibitors of neutrophil elastase and of AAT polymerization, autophagy-enhancing drugs and gene therapy approaches.

EXPERT OPINION

We conclude with a discussion of our approach to managing patients with AATD and use of augmentation therapy.

Alpha-1-antitrypsin and other proteinase inhibitors

Since the end of the 1980s augmentation therapy with alpha-1 antitrypsin (AAT) from human plasma has been available for specific treatment of emphysema due to AAT deficiency. Intravenous augmentation therapy has demonstrated to be safe and weekly infusions of AAT have demonstrated to result in plasma AAT concentration above those considered protective for the lungs. Randomized, placebo-controlled clinical trials have confirmed a reduction in the decline in lung density in patients receiving augmentation therapy. This is the first example of an antiprotease effective in restoring the protease/antiprotease imbalance in the lungs and changing the natural history of congenital emphysema. On the basis of the results obtained with the long-term infusion of AAT, there is growing interest in the possible use of antiprotease treatment in patients with smokers COPD. However, no drugs are yet available to increase antiprotease protection of the lower airways of smokers.

Inhibition of IL-32 activation by α-1 antitrypsin suppresses alloreactivity and increases survival in an allogeneic murine marrow transplantation model

Interleukin (IL)-32 was originally identified in natural killer cells and IL-2-activated human T lymphocytes. As T cells are activated in allogeneic transplantation, we determined the role of IL-32 in human mixed lymphocyte cultures (MLCs) and GVHD. In allogeneic MLCs, IL-32 increased two-fold in responding T cells, accompanied by five-fold increases of TNFα, IL-6, and IL-8. After allogeneic hematopoietic cell transplantation, IL-32 mRNA levels in blood leukocytes were statistically significantly higher in patients with acute GVHD (n = 10) than in serial samples from patients who did not develop acute GVHD (n = 5; P = .02). No significant changes in IL-32 levels were present in patients with treated (n = 14) or untreated (n = 8) chronic GVHD, compared with healthy controls (n = 8; P = .5, and P = .74, respectively). As IL-32 is activated by proteinase-3 (PR3), we determined the effect of the serine protease inhibitor α-1 antitrypsin (AAT) on IL-32 levels and showed suppression of IL-32 and T-lymphocyte proliferation in MLCs. In an MHC-minor antigen disparate murine transplant model, preconditioning and postconditioning treatment with AAT resulted in attenuation or prevention of GVHD and superior survival compared with albumin-treated controls (80% vs 44%; P = .04). These findings suggest that AAT modulates immune and inflammatory functions and may represent a novel approach to prevent or treat GVHD.

A review of α1-antitrypsin deficiency

α(1)-Antitrypsin (AAT) deficiency is an underrecognized genetic condition that affects approximately 1 in 2,000 to 1 in 5,000 individuals and predisposes to liver disease and early-onset emphysema. AAT is mainly produced in the liver and functions to protect the lung against proteolytic damage (e.g., from neutrophil elastase). Among the approximately 120 variant alleles described to date, the Z allele is most commonly responsible for severe deficiency and disease. Z-type AAT molecules polymerize within the hepatocyte, precluding secretion into the blood and causing low serum AAT levels (∼ 3-7 μM with normal serum levels of 20-53 μM). A serum AAT level of 11 μM represents the protective threshold value below which the risk of emphysema is believed to increase. In addition to the usual treatments for emphysema, infusion of purified AAT from pooled human plasma-so-called "augmentation therapy"-represents a specific therapy for AAT deficiency and raises serum levels above the protective threshold. Although definitive evidence from randomized controlled trials of augmentation therapy is lacking and therapy is expensive, the available evidence suggests that this approach is safe and can slow the decline of lung function and emphysema progression. Promising novel therapies are under active investigation.

Why has it been so difficult to prove the efficacy of alpha-1-antitrypsin replacement therapy? Insights from the study of disease pathogenesis

Alpha-1-antitrypsin is the most abundant circulating protease inhibitor. It is mainly produced by the liver and secreted into the circulation where it acts to prevent excessive proteolytic damage in the lungs by the enzyme neutrophil elastase. The most common severe deficiency allele is the Z mutation, which causes the protein to self-associate into ordered polymers. These polymers accumulate within hepatocytes to cause liver damage. The resulting lack of circulating α₁-antitrypsin predisposes the Z homozygote to proteolytic lung damage and emphysema. Other pathways may also contribute to the development of lung disease. In particular, polymers of Z α₁-antitrypsin can form within the lung where they act as a pro-inflammatory stimulus that may exacerbate protease-mediated lung damage. Researchers recognized in the 1980s that plasma α₁-antitrypsin levels could be restored by intravenous infusions of purified human protein. Alpha-1-antitrypsin replacement therapy was introduced in 1987 but subsequent clinical trials have produced conflicting results, and to date there remains no widely accepted clinical evidence of the efficacy of α₁-antitrypsin replacement therapy. This review addresses our current understanding of disease pathogenesis in α₁-antitrypsin deficiency and questions why this treatment in isolation may not be effective. In particular it discusses the possible role of α₁-antitrypsin polymers in exacerbating intrapulmonary inflammation and attenuating the efficacy of α₁-antitrypsin replacement therapy.

The role of augmentation therapy in alpha-1 antitrypsin deficiency

BACKGROUND

Since the recognition of alpha-1 antitrypsin deficiency (A1ATD) in 1963, interest in this condition has increased dramatically. A1ATD is now recognized as the only known genetic condition that leads to emphysema/chronic obstructive pulmonary disease (COPD) in many individuals with the condition. Augmentation therapy with plasma-derived alpha-1 antitrypsin (A1AT) was first introduced in 1987. OBJECTIVES AND SCOPE: To review current evidence on the efficacy, tolerability and biochemical composition of commercially available A1AT augmentation therapies. Literature was sought via electronic searching of bibliographic databases (MEDLINE) and other sources. No language or time period settings were applied. This is a narrative, descriptive review rather than a formal, systematic review.

FINDINGS

Evidence of the therapeutic efficacy of A1AT augmentation therapy is beginning to accumulate, although further randomized, controlled trials are necessary. Clinical studies have reported reduced rates of lung function decline in COPD patients who received augmentation therapy, and significant benefit is seen in patients with forced expiratory volume in 1 second initially in the range of 35-49% of predicted normal. Augmentation therapy has also been shown to decrease the frequency of severe COPD exacerbations and to significantly increase survival rate. Biochemical studies have convincingly demonstrated that weekly intravenous infusion of each of the available plasma-derived A1AT preparations maintains serum A1AT levels above the putative protective threshold. Augmentation therapy with intravenous A1AT is generally well tolerated and long-term therapy in patients with severe A1ATD and pulmonary emphysema is feasible. Differences in the purification processes of available A1AT products are reflected in their relative purities and heterogeneities (abundance of A1AT isoforms), although the commercially available preparations are bioequivalent. Further studies are required to clarify whether variations in biochemical composition of purified A1AT are clinically important.

CONCLUSION

Intravenous augmentation therapy with A1AT currently represents the only viable and specific treatment option for patients with A1ATD.

Pharmacokinetic comparability of Prolastin®-C to Prolastin® in alpha₁-antitrypsin deficiency: a randomized study

Background

Alpha₁-antitrypsin (AAT) deficiency is characterized by low blood levels of alpha₁-proteinase inhibitor (alpha₁-PI) and may lead to emphysema. Alpha₁-PI protects pulmonary tissue from damage caused by the action of proteolytic enzymes. Augmentation therapy with Prolastin^® (Alpha₁-Proteinase Inhibitor [Human]) to increase the levels of alpha₁-PI has been used to treat individuals with AAT deficiency for over 20 years. Modifications to the Prolastin manufacturing process, incorporating additional purification and pathogen-reduction steps, have led to the development of an alpha₁-PI product, designated Prolastin^®-C (Alpha₁-Proteinase inhibitor [Human]). The pharmacokinetic comparability of Prolastin-C to Prolastin was assessed in subjects with AAT deficiency.

Methods

In total, 24 subjects were randomized to receive 60 mg/kg of functionally active Prolastin-C or Prolastin by weekly intravenous infusion for 8 weeks before crossover to the alternate treatment for another 8 weeks. Pharmacokinetic plasma samples were drawn over 7 days following last dose in the first treatment period and over 10 days following the last dose in the second period. The primary end point for pharmacokinetic comparability was area under the plasma concentration versus time curve over 7 days post dose (AUC_{0-7 days}) of alpha₁-PI determined by potency (functional activity) assay. The crossover phase was followed by an 8-week open-label treatment phase with Prolastin-C only.

Results

Mean AUC_{0-7 days} was 155.9 versus 152.4 mg*h/mL for Prolastin-C and Prolastin, respectively. The geometric least squares mean ratio of AUC_{0-7 days} for Prolastin-C versus Prolastin had a point estimate of 1.03 and a 90% confidence interval of 0.97-1.09, demonstrating pharmacokinetic equivalence between the 2 products. Adverse events were similar for both treatments and occurred at a rate of 0.117 and 0.078 per infusion for Prolastin-C (double-blind treatment phase only) and Prolastin, respectively (p = 0.744). There were no treatment-emergent viral infections in any subject for human immunodeficiency virus, hepatitis B or C, or parvovirus B19 during the course of the study.

Conclusion

Prolastin-C demonstrated pharmacokinetic equivalence and a comparable safety profile to Prolastin.

Trial Registration

ClinicalTrials.gov Identifier: NCT00295061

Augmentation therapy in alpha-1 antitrypsin deficiency: advances and controversies

Alpha-1 antitrypsin (AAT) deficiency is a hereditary condition characterized by low levels of AAT in plasma and hence diffusion into tissues. One of the most relevant characteristics of the disease is the development of panacinar emphysema due to an imbalance between proteases and antiproteases in the presence of environmental triggers. Left untreated, severe obstructive lung disease may develop. Avoidance of environmental triggers such as cigarette smoking constitutes a critical component of AAT deficiency treatment. Intravenous augmentation therapy is the only specific therapy for the condition that has been approved by the US Food and Drug Administration (FDA). While this therapy likely slows the rate of progression of emphysema and may improve survival in selected individuals with severe AAT deficiency, the gold standard for proof of efficacy is lacking. Areas where controversy exists regarding the use of AAT augmentation therapy include: (1) indications for treatment, (2) selection of specific AAT augmentation therapy, (3) appropriate dose and interval of administration, (4) cost effectiveness, (5) frequency and mode of follow up of treated patients, (6) use of augmentation therapy after lung transplantation, (7) use of recombinant AAT supplementation, (8) alternative delivery routes, and (9) genetic therapy. In this review we describe the advances in treatment and try to address some of the current controversies in AAT deficiency management.

Augmentation therapy for alpha1 antitrypsin deficiency: a meta-analysis

BACKGROUND

Augmentation with exogenous alpha1-antitrypsin (alpha1-AT) is the only specific therapy for alpha1-AT deficiency. Uncertainty persists concerning its effectiveness.

PURPOSE

To test the hypothesis that augmentation therapy in patients with alpha1-AT deficiency slows the decline in FEV1.

STUDY SELECTION

Randomized and nonrandomized clinical studies with either parallel-group design or single cohort pre-post design were eligible if they compared augmentation therapy with a control regimen and if long-term (> 1 y) longitudinal FEV1 follow-up data were collected.

DATA SYNTHESIS

FEV1 data from five trials with 1509 patients were combined by random effects meta-analysis. The decline in FEV1 was slower by 23% (absolute difference, 13.4 ml/year; CI, 1.5 to 25.3 ml/year) among all patients receiving augmentation therapy. This overall protective effect reflected predominantly the results in the subset of patients with baseline FEV1 30-65% of predicted. In that subset, augmentation was associated with a 26% reduction in rate of FEV1 decline (absolute difference, 17.9 ml/year; CI, 9.6 to 26.1 ml/year). Similar trends amongst patients with baseline FEV1 percent of predicted < 30% or > 65% were not statistically significant.

CONCLUSIONS

This meta-analysis supports the conclusion that augmentation can slow lung function decline in patients with AAT deficiency Patients with moderate obstruction are most likely to benefit.

Alpha-1 antitrypsin (AAT) deficiency - what are the treatment options?

Alpha-1 antitrypsin (AAT) deficiency is an under-recognized genetic condition that predisposes to liver disease and early-onset emphysema. Although AAT is mainly produced in the liver, its main function is to protect the lung against proteolytic damage from neutrophil elastase. The most common mutation responsible for severe AAT deficiency, the so-called Z variant, reduces serum levels by promoting polymerization of the molecule within the hepatocyte, thereby reducing secretion. Serum levels below the putative protective threshold level of 11 micromolar (mumol/L) increase the risk of emphysema. In addition to the usual treatments for emphysema, infusion of purified AAT from pooled human plasma represents a specific therapy for AAT deficiency and raises serum and epithelial lining fluid levels above the protective threshold. Substantial evidence supports the biochemical efficacy of this approach, particularly for the weekly infusion regimen. Definitive evidence of clinical efficacy is still needed, as the two available randomized controlled trials showed non-significant trends towards slowing rates of loss of lung density on lung computerized axial tomography. However, concordant results of prospective cohort studies suggest that augmentation therapy has efficacy in slowing the rate of decline of lung function in patients with moderate airflow obstruction and severe deficiency of AAT. Overall, augmentation therapy is well-tolerated and, despite its failure to satisfy criteria for cost-effectiveness, is recommended because it is the only currently available specific therapy for AAT deficiency.

Targeted treatment in COPD: a multi-system approach for a multi-system disease

Chronic obstructive pulmonary disease is a varied condition when examined from a number of different perspectives including factors which influence disease development, pathological process and clinical features. There may be a complex interaction between the degree by which each of these processes influences the development of COPD and the subsequent clinical phenotype with which the patient presents. The varied host response and subsequent clinical phenotype has generated much interest in recent years. It is possible that failure of treatment to impact on mortality and reverse the disease process is because of the heterogeneous nature of the condition. Identification and targeted treatment of clinical and pathological phenotypes within the broad spectrum of COPD may therefore improve outcome. This article will review previous work which has attempted to phenotype COPD and identify if specific treatment for these phenotypes has been shown to be of benefit. It will examine the work on pathological processes and clinical manifestations, both pulmonary and systemic, and will focus on pharmacological therapies.

Small-molecule peptides inhibit Z alpha1-antitrypsin polymerization

The Z variant of 1-antitrypsin (AT) polymerizes within the liver and gives rise to liver cirrhosis and the associated plasma deficiency leads to emphysema. In this work, a combinatorial approach based on the inhibitory mechanism of (alpha1)-AT was developed to arrest its pathogenic polymerization. One peptide, Ac-TTAI-NH(2), emerged as the most tight-binding ligand for Z (alpha1)-AT. Characterization of this tetrapeptide by gel electrophoresis and biosensor analysis revealed its markedly improved binding specificity and affinity compared with all previously reported peptide inhibitors. In addition, the peptide is not cytotoxic to lung cell lines. A model of the peptide-protein complex suggests that the peptide interacts with nearby residues by hydrogen bonds, hydrophobic interactions, and cavity-filling stabilization. The combinatorially selected peptide not only effectively blocks the polymerization but also promotes dissociation of the oligomerized (alpha1)-AT. These results are a significant step towards the potential treatment of Z (alpha1)-AT related diseases.

Safety and efficacy of alpha-1-antitrypsin augmentation therapy in the treatment of patients with alpha-1-antitrypsin deficiency

Alpha-1-antitrypsin deficiency (AATD), also known as alpha1-proteinase inhibitor deficiency, is an autosomal co-dominant condition. The genotypes associated with AATD include null, deficient, and dysfunctional alpha-1-antitrypsin (A1AT) variants, which result in low levels of circulating functional A1AT, unbalanced protease activity, and an increased risk of developing lung emphysema, the leading cause of morbidity in these patients. Furthermore, the most common abnormal genotype, Pi*ZZ may also cause trapping of abnormally folded protein polymers in hepatocytes causing liver dysfunction. A major focus of therapy for patients with lung disease due to AATD is to correct the A1AT deficiency state by augmenting serum levels with intravenous infusions of human plasma-derived A1AT. This strategy has been associated with effective elevations of A1AT levels and function in serum and lung epithelial fluid and observational studies suggest that it may lead to attenuation in lung function decline, particularly in patients with moderate impairment of lung function. In addition, an observational study suggests that augmentation therapy is associated with a reduction of mortality in subjects with AATD and moderate to severe lung impairment. More recent randomized placebo-controlled studies utilizing computer scan densitometry suggest that this therapy attenuates lung tissue loss. Augmentation therapy has a relative paucity of side effects, but it is highly expensive. Therefore, this therapy is recommended for patients with AATD who have a high-risk A1AT genotype with plasma A1AT below protective levels (11 μM) and evidence of obstructive lung disease. In this article, we review the published evidence of A1AT augmentation therapy efficacy, side effects, and safety profile.

α1-Antitrypsin deficiency, chronic obstructive pulmonary disease and the serpinopathies

α1-Antitrypsin is the prototypical member of the serine proteinase inhibitor or serpin superfamily of proteins. The family includes α1-antichymotrypsin, C1 inhibitor, antithrombin and neuroserpin, which are all linked by a common molecular structure and the same suicidal mechanism for inhibiting their target enzymes. Point mutations result in an aberrant conformational transition and the formation of polymers that are retained within the cell of synthesis. The intracellular accumulation of polymers of mutant α1-antitrypsin and neuroserpin results in a toxic gain-of-function phenotype associated with cirrhosis and dementia respectively. The lack of important inhibitors results in overactivity of proteolytic cascades and diseases such as COPD (chronic obstructive pulmonary disease) (α1-antitrypsin and α1-antichymotrypsin), thrombosis (antithrombin) and angio-oedema (C1 inhibitor). We have grouped these conditions that share the same underlying disease mechanism together as the serpinopathies. In the present review, the molecular and pathophysiological basis of α1-antitrypsin deficiency and other serpinopathies are considered, and we show how understanding this unusual mechanism of disease has resulted in the development of novel therapeutic strategies.

[Alpha-1 antitrypsin deficiency: diagnosis and treatment]

Alpha-1 antitrypsin deficiency is a recently identified genetic disease that occurs almost as frequently as cystic fibrosis. It is caused by various mutations in the SERPINA1 gene, and has numerous clinical implications. Alpha-1 antitrypsin is mainly produced in the liver and acts as an antiprotease. Its principal function is to inactivate neutrophil elastase, preventing tissue damage. The mutation most commonly associated with the clinical disease is the Z allele, which causes polymerization and accumulation within hepatocytes. The accumulation of and the consequent reduction in the serum levels of alpha-1 antitrypsin cause, respectively, liver and lung disease, the latter occurring mainly as early emphysema, predominantly in the lung bases. Diagnosis involves detection of low serum levels of alpha-1 antitrypsin as well as phenotypic confirmation. In addition to the standard treatment of chronic obstructive pulmonary disease, specific therapy consisting of infusion of purified alpha-1 antitrypsin is currently available. The clinical efficacy of this therapy, which appears to be safe, has yet to be definitively established, and its cost-effectiveness is also a controversial issue that is rarely addressed. Despite its importance, in Brazil, there are no epidemiological data on the prevalence of the disease or the frequency of occurrence of deficiency alleles. Underdiagnosis has also been a significant limitation to the study of the disease as well as to appropriate treatment of patients. It is hoped that the creation of the Alpha One International Registry will resolve these and other important issues.

[Augmentation therapy with alpha-1 antitrypsin: 20 year- follow-up of a deficient patient]

INTRODUCTION

Alpha one antitrypsin deficiency is a rare genetic disorder occurring principally in patients with the PiZZ phenotype. This deficiency can lead to pulmonary emphysema which impairs quality of life and which may progress to respiratory failure. The diagnosis is based on the presence of emphysema typically with a basal preponderance and airflow obstruction and is confirmed by measuring A1AT levels. A1AT replacement is the only specific therapy for this condition.

OBSERVATION

We describe the 1st patient with A1AT deficiency treated in this way in France. The patient was 52 years old at the start of treatment with A1AT replacement, initially in hospital and then at their place of residence. Treatment was initiated in the context of progressive breathlessness, the presence of emphysema and confirmation of the biochemical deficit. The patient received 4 g of AIAT per week in combination with inhaled corticosteroids and ongoing physical rehabilitation. Follow up over 20 years has revealed a slowing in the decline in spirometric measurements. No problems with tolerating the treatment have been reported.

CONCLUSION

In this clinical case replacement therapy appeared to show clinical benefits and was well tolerated.

alpha1-Antitrypsin monotherapy induces immune tolerance during islet allograft transplantation in mice

Human pancreatic islet transplantation offers diabetic patients tight glucose control but has low graft survival rates. The immunosuppressive drugs that are administered to graft recipients lack the antiinflammatory benefits of corticosteroids because of their diabetogenic effects. The serum protease inhibitor alpha1-antitrypsin (AAT) possesses antiinflammatory properties and reduces cytokine-mediated islet damage. In the present study, diabetic mice were grafted with allogeneic islets and treated with AAT monotherapy (n = 24). After 14 days of treatment, mice remained normoglycemic and islet allografts were functional for up to 120 treatment-free days. After graft removal and retransplantation, mice accepted same-strain islets but rejected third-strain islets, thus confirming that specific immune tolerance had been induced. Explanted grafts exhibited a population of T regulatory cells in transplant sites. According to RT-PCR, grafts contained high levels of mRNA for foxp3, cytotoxic T lymphocyte antigen-4, TGF-beta, IL-10, and IL-1 receptor antagonist; expression of proinflammatory mediators was low or absent. After implantation of skin allografts, AAT-treated mice had greater numbers of foxp3-positive cells in draining lymph nodes (DLNs) compared with control treatment mice. Moreover, dendritic cells in DLNs exhibited an immature phenotype with decreased CD86 activation marker. Although the number of CD3 transcripts decreased in the DLNs, AAT did not affect IL-2 activity in vitro. Thus, AAT monotherapy provides allografts with antiinflammatory conditions that favor development of antigen-specific T regulatory cells. Because AAT treatment in humans is safe, its use during human islet transplantation may be considered.

Human alpha 1-antitrypsin therapy induces fatal anaphylaxis in non-obese diabetic mice

Previous studies have shown that human alpha-1 antitrypsin (hAAT) gene delivery prevents type 1 diabetes (T1D) in non-obese diabetic (NOD) mice. Furthermore, hAAT protein administration prolongs acceptance of islet allografts. Therefore, we evaluated the use of purified hAAT protein therapy to prevent T1D in NOD mice. Female NOD, non-obese resistant (NOR), Balb/c and C57BL/6 mice were injected intraperitoneally with vehicle alone or vehicle containing hAAT, human albumin or mouse albumin (or mg/injection/mouse; 2x/week). Preparations of clinical-grade hAAT included API(R), Aralast, Prolastin and Zemaira. Surprisingly, hAAT administration was associated with a high rate of fatal anaphylaxis. In studies seeking T1D prevention at 4 weeks of age, 100% mice died after six injections of hAAT. When administrated at 8-10 weeks of age, most (80-100%) NOD mice died following the fourth injection of hAAT, while 0% of Balb/c and C57BL/6 mice and 10% of NOR mice died. Interestingly, repeated injections of human albumin, but not mouse albumin, also induced sudden death in NOD mice. Antibodies to hAAT were induced 2-3 weeks after hAAT administration and death was prevented by treatment with anti-platelet-activating factor along with anti-histamine. In studies of disease reversal in NOD mice, using the four pharmaceutical grade formulations of hAAT, anaphylactic deaths were observed with all hAAT preparations. The propensity for fatal anaphylaxis following antigenic administration appears to be NOD- but not hAAT-specific. The susceptibility of NOD mice to hypersensitivity provides a significant limitation for testing of hAAT. Development of strategies to avoid this unwanted response is required to use this promising therapeutic agent for T1D.

Augmentation therapy in alpha-1 antitrypsin deficiency

BACKGROUND

Alpha-1 antitrypsin deficiency is a genetic disorder that leads to early-onset emphysema. Recently, exogenous supplementation of the enzyme has become a therapeutic alternative.

OBJECTIVE

To review the role of so-called augmentation therapy with pooled human plasma alpha-1 antitrypsin as a specific treatment for emphysema caused by alpha-1 antitrypsin deficiency.

METHODS

The authors performed a Medline (1966 - 2007) search with the keywords 'alpha-1 antitrypsin deficiency' and 'therapy'. The authors focused on articles regarding biochemical and clinical efficacy.

RESULTS/CONCLUSION

Augmentation therapy has been shown to raise antiprotease serum and epithelial lining fluid levels above the 'protective threshold' value. Evidence suggests that this approach slows the decline in lung function, could reduce infection rates, might enhance survival, and is well tolerated. Questions about the cost-effectiveness of this therapy remain.