Replacement therapy for hereditary alpha1-antitrypsin deficiency. A program for long-term administration

Human plasma-derived alpha1 -proteinase inhibitor in patients with new-onset type 1 diabetes mellitus: A randomized, placebo-controlled proof-of-concept study

BACKGROUND

While circulating levels of alpha₁ -proteinase inhibitor (alpha₁ -PI) are typically normal, antiprotease activity appears to be compromised in patients with Type 1 diabetes mellitus (T1DM). Because alpha₁ -PI [human] (alpha₁ -PI[h]) therapy can inhibit pro-inflammatory mediators associated with β-cell destruction and reduced insulin production, it has been proposed for T1DM disease prevention. The aim of this study was to evaluate safety, tolerability, and efficacy of intravenous (IV) alpha₁ -PI[h] in preserving C-peptide production in newly diagnosed T1DM patients.

PARTICIPANTS

Seventy-six participants (aged 6-35 years) were randomized at 25 centers within 3 months of T1DM diagnosis.

METHODS

A Phase II, multicenter, partially blinded, placebo-controlled, proof-of-concept study evaluating four dosing regimens of alpha₁ -PI[h] (NCT02093221, GTI1302): weekly IV infusions of either 90 or 180 mg/kg, each for either 13 or 26 weeks. Safety and efficacy were monitored over 52 weeks with an efficacy evaluation planned at 104 weeks. The primary efficacy endpoint was change from baseline in the 2-h area-under-the-curve C-peptide level from a mixed-meal tolerance test at 52 weeks. A battery of laboratory tests, including inflammatory biomarkers, constituted exploratory efficacy variables.

RESULTS

Infusions were well tolerated with no new safety signals. All groups exhibited highly variable declines in the primary outcome measure at 52 weeks with no statistically significant difference from placebo. Interleukin-6 (IL-6) was reduced from baseline in all alpha₁ -PI treatment groups but not the placebo group.

CONCLUSION

Pharmacologic therapy with alpha₁ -PI[h] is safe, well tolerated, and able to reduce IL-6 levels; however, due to variability in the efficacy endpoint, its effects on preservation of C-peptide production were inconclusive.

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.

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.

Benefits Among Patients with Alpha-1 Antitrypsin Deficiency Enrolled in a Disease Management and Prevention Program

Rationale: Alpha-1 antitrypsin deficiency (AATD) is characterized by decreased circulating levels or activity of the serum protein, alpha-1 antitrypsin, which increases risk for chronic lung or liver injury and may lead to diseases such as chronic obstructive pulmonary disease (COPD). Currently there is no cure for AATD, and it is largely controlled through disease management and augmentation therapy. This study was designed to describe characteristics of patients enrolled in a disease management and prevention program. Methods: Data from questionnaires administered by AlphaNet were obtained on 4747 AATD patients and included demographic information, medical history, lifestyle choices, and adherence to the Alpha-1 Disease Management and Prevention Program (ADMAPP). A total of 1221 participants (25.72%) had missing adherence information and were excluded, leaving a final study population of 3526. Questionnaire answer dates ranged from May 29, 2008 to February 14, 2015. Logistic regression was used to adjust for demographic factors and comorbidities, comparing the populations stratified by adherence to ADMAPP. Results: After adjustment for age, sex, race, Charlson Comorbidity Index, and income level, individuals who self-reported any adherence to ADMAPP were more likely to feel informed about their condition (odds ratio[OR]_adj 4.95, 95% confidence interval[CI][3.24, 7.57]), and be taking preventive measures, such as smoking cessation (OR_adj 0.47, 95% CI [0.31, 0.70]), appropriate immunizations, and self-reported exercise (OR_adj 2.07, 95% CI [1.74, 2.47]). Conclusions: This study suggests that ADMAPP may be a useful tool for informing and improving preventive measures taken by individuals with AATD. Future studies are needed to clarify the observed associations and study additional outcomes.

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.

Reduction of severe exacerbations and hospitalization-derived costs in alpha-1-antitrypsin-deficient patients treated with alpha-1-antitrypsin augmentation therapy

Objective: Severe exacerbations in alpha-1-antitrypsin (AAT)-deficient patients with chronic obstructive pulmonary disease (COPD) and/or emphysema are a major cause of hospitalization. A multicentre, observational, retrospective study was undertaken to evaluate the effect of continuous AAT augmentation therapy in reducing the incidence of exacerbations in these patients.

Methods: Patients treated with Trypsone® or Prolastin® for at least 18 months were recruited if their medical records for 18 months before starting augmentation therapy were available. The number of mild and severe exacerbations in the two periods was compared and hospitalization-related costs were analysed.

Results: A total of 127 patients were recruited; 75 of them experienced at least one exacerbation in the period prior to augmentation. In the treatment period, the mean number of exacerbations per patient was reduced in both the total population and the population with exacerbations (mean ± SD: 1.2 ± 1.6 versus 1.0 ± 2.2 and 2.0 ± 1.6 versus 1.4 ± 2.7, respectively; p < 0.01). The percentage of patients experiencing exacerbations was reduced in the total population (59.1% versus 44.1%; p < 0.05). In the patient subgroup of the total population who experienced a change in their number of exacerbations between the two periods, 43.7% had a reduction and 21.4% had an increase ( p < 0.01). The number of severe exacerbations diminished in 42.9% of this subgroup and increased in 12.0% ( p < 0.001). Most adverse events were nonserious or not related to treatment. Hospitalization costs savings per patient associated with treatment ranged from approximately €400 to €900 ( p < 0.05).

Conclusions: Augmentation therapy with AAT concentrates was associated with a reduction in the incidence and severity of exacerbations in AAT-deficient patients, which resulted in lower hospitalization expenditures.

Asthma and COPD in alpha-1 antitrypsin deficiency. Evidence for the Dutch hypothesis

This review summarizes the current information on the relationship between severe alpha-1 antitrypsin deficiency (AATD), asthma and COPD. AATD is a genetic predisposition to the development of early COPD in susceptible individuals and reduction in known factors that enhance lung function loss is the paramount aim of management. Asthma is one controllable condition that leads to the accelerated decline in lung function. Current literature indicates that asthma signs and symptoms are common in those AATD with or without COPD and that bronchodilator response is a risk factor for FEV(1) decline. Furthermore AATD itself predisposes to airway hyper responsiveness, an essential ingredient for reversible airflow obstruction. In the absence of well-characterized markers to distinguish COPD from asthma, clinical diagnosis leads to a delay in the recognition that asthma symptoms such as wheezing can be an early manifestation of COPD in AATD. In addition failure to appreciate asthma overlap in AATD may lead to inadequate suppression of airway inflammation leading to the development of airflow obstruction. The implications of this are discussed as are potential approaches and recommendations for treatment.

[Alpha1-antitrypsin deficiency]

Alpha(1)-antitrypsin deficiency is characterized by a pathologic reduction of the serum concentration of alpha(1)-antitrypsin, the most important antiprotease in man. It is one of the most common hereditary diseases in Caucasians. Approximately 2% of obstructive airway diseases are caused by alpha(1)-antitrypsin deficiency. Patients above 35 years may develop lung emphysema, especially in the lower lobes. Symptoms are those of chronic obstructive pulmonary disease such as cough, sputum expectoration, and progressive dyspnoea. Patients with homozygous defect often develop cholestatic hepatitis in the neonatal period. However, only few adult patients develop chronic liver disease up to liver cirrhosis with an elevated risk for malignant liver tumors. The diagnostic hallmark is the reduced serum concentration of alpha(1)-antitrypsin while genetic testing proves the defect. An early recognition of the disease is decisive for prophylactic and therapeutic measures. Smoking should be stopped immediately. Treatment of lung disease includes physiotherapy, antiobstructive and antiinflammatory medication, augmentation with human alpha(1)-antitrypsin and lung surgery including lung transplantation. Liver toxins should be avoided. Besides experimental therapeutic approaches, liver disease can only be treated by liver transplantation.

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.

Augmentation therapy for emphysema due to alpha-1-antitrypsin deficiency

Alpha-1 antitrypsin deficiency (AAT) is a hereditary recessive autosomal disease caused by mutations in the AAT gene. This disease is characterized by abnormally low AAT concentrations in plasma, which, in its homozygote form, carries a high risk for the development of early pulmonary emphysema and liver damage. Since the end of the 1980s augmentation therapy with AAT from human plasma has been available for specific treatment of emphysema due to AAT deficiency. Intravenous augmentation therapy has been demonstrated to be safe and weekly infusions of AAT have resulted in plasma AAT concentrations above those considered protective for the lungs. However, life-long weekly infusions are not well accepted by patients, therefore pharmacokinetic studies have been performed to try to individualize the therapeutic regimen in order to obtain adequate trough serum AAT levels with prolonged intervals of administration. Therapeutic regimens administered every two weeks appear to be safe and result in adequate trough serum concentrations, but less-frequent administrations result in trough levels below the target. Alpha-1-antitrypsin deficiency is largely unrecognized and underdiagnosed. The foundation of national and international registries is a valid strategy to increase awareness about the disease and collect information about the natural history of this deficiency. Furthermore, the identification of a large number of patients will allow the development of new clinical trials aimed at finding better treatments for this infrequent condition.

Alpha-1 antitrypsin deficiency: pathogenesis, clinical presentation, diagnosis, and treatment

Alpha-1 antitrypsin deficiency is an inherited disease affecting the lung and liver. The typical pulmonary manifestation is chronic obstructive pulmonary disease and emphysema. Severe chronic obstructive pulmonary disease may occur in young adulthood, and terminal respiratory insufficiency causes premature death in many patients. In the liver, alpha-1 antitrypsin deficiency may manifest as benign neonatal hepatitis syndrome; a small percentage of adults develop liver fibrosis, with progression to cirrhosis and hepatocellular carcinoma. The alpha-1 antitrypsin molecule is a serine protease inhibitor that is predominantly produced in the liver. Its most important physiologic functions are the protection of pulmonary tissue from aggressive proteolytic enzymes and regulation of pulmonary immune processes. Diagnosis of alpha-1 antitrypsin deficiency can be established by measurement of the serum alpha-1 antitrypsin concentration or by genetic analysis. Treatment is similar to the usual treatment for patients with chronic obstructive pulmonary disease. A further option is substitution therapy with human alpha-1 antitrypsin. The targets of treatment are the prevention of the accelerated decline of pulmonary function, reduction of lung infections, and improvements in exercise capacity.

Characterization of the relation between CT technical parameters and accuracy of quantification of lung attenuation on quantitative chest CT

OBJECTIVE

The purpose of this study was to assess the compromise between CT technical parameters and the accuracy of CT quantification of lung attenuation.

MATERIALS AND METHODS

Materials that simulate water (0 H), healthy lung (-650 H), borderline emphysematous lung (-820 H), and severely emphysematous lung (-1,000 H) were placed at both the base and the apex of the lung of an anthropomorphic phantom and outside the phantom. Transaxial CT images through the samples were obtained while the effective tube current was varied from 440 to 10 mAs, kilovoltage from 140 to 80 kVp, and slice thickness from 0.625 to 10 mm. Mean +/- SD attenuation within the samples and the standard quantitative chest CT measurements, the percentage of pixels with attenuation less than -910 H and 15th percentile of attenuation, were computed.

RESULTS

Outside the phantom, variations in CT parameters produced less than 2.0% error in all measurements. Within the anthropomorphic phantom at 30 mAs, error in measurements was much larger, ranging from zero to 200%. Below approximately 80 mAs, mean attenuation became increasingly biased. The effects were most pronounced at the apex of the lungs. Mean attenuation of the borderline emphysematous sample of apex decreased 55 H as the tube current was decreased from 300 to 30 mAs. Both the 15th percentile of attenuation and percentage of pixels with less than -910 H attenuation were more sensitive to variations in effective tube current than was mean attenuation. For example, the -820 H sample should have 0% of pixels less than -910 H, which was true at 400 mA. At 30 mA in the lung apex, however, the measurement was highly inaccurate, 51% of pixels being below this value. Decreased kilovoltage and slice thickness had analogous, but lesser, effects.

CONCLUSION

The accuracy of quantitative chest CT is determined by the CT acquisition parameters. There can be significant decreases in accuracy at less than 80 mAs for thin slices in an anthropomorphic phantom, the most pronounced effects occurring in the lung apex.

Alpha-1-antitrypsin deficiency: optimal therapeutic regimen based on population pharmacokinetics

BACKGROUND

Exogenous doses of 60 mg/kg alpha(1)-antitrypsin (AAT) every 7 days are recommended in patients with severe AAT deficiency. However, long term administration of weekly doses is not well accepted by patients. Using pharmacokinetic simulations, we evaluated whether steady state minimum concentrations of total AAT can be maintained above the threshold of 0.5 g/l with longer intervals between doses.

METHODS

Several sets of exogenous AAT versus time simulations were studied using a non-linear mixed effect approach with dosage regimens every 7, 14, 21, and 28 days. For each regimen the mean exogenous AAT trough concentrations and 5/95th percentiles were determined. The results obtained were applied to estimate the individual optimal dose at 7, 14, and 21 days in six patients using Bayesian analysis.

RESULTS

The simulations showed that a dose of 50 mg/kg AAT every 7 days was sufficient to obtain nadir concentrations. Doses of 120 and 100 mg/kg every 14 days were also adequate, but 180 mg/kg given every 21 days required total AAT monitoring to avoid underdosage. Longer intervals were inappropriate. Dosage individualisation confirmed that AAT infusions given every 14 days maintained the nadir level of 0.5 g/l without a significant dose increase compared with current practice. When the time span between doses was fixed at 21 days, a mean relative AAT dose enhancement of 91% and 13%, respectively, was required to achieve sustained total AAT concentrations above the target level for 100% and 85% of the interval between doses.

CONCLUSIONS

It is feasible to extend the interval between doses of AAT to 14 or 21 days to achieve adequate trough total AAT concentrations. This study might be used as a starting point for clinical evaluation of the regimens described.

Intein-mediated protein purification of fusion proteins expressed under high-cell density conditions in E. coli

The intein-mediated purification system has the potential to significantly reduce the recovery costs of industrial recombinant proteins. The ability of inteins to catalyze a controllable peptide bond cleavage reaction can be used to separate a recombinant protein from its affinity tag during affinity purification. Inteins have been combined with a chitin-binding domain to serve as a self-cleaving affinity tag, facilitating highly selective capture of the fusion protein on an inexpensive substrate--chitin (IMPACT) system, New England Biolabs, Beverly, MA). This purification system has been used successfully at a lab scale in low cell density cultures, but has not been examined comprehensively under high-cell density conditions in defined medium. In this study, the intein-mediated purification of three commercially relevant proteins expressed under high-cell density conditions in E. coli was studied. Additionally, losses during the purification process were quantified. The data indicate that the intein fusion proteins expressed under high cell density fermentations were stable in vivo after induction for a significant duration, and the intein fusion proteins could undergo thiol or pH and temperature initiated cleavage reaction in vitro. Thus, the intein-mediated protein purification system potentially could be employed for the production of recombinant proteins at the industrial-scale.

Recombinant human alpha-1 proteinase inhibitor: towards therapeutic use

Human alpha-1-proteinase inhibitor is a well-characterized protease inhibitor with a wide spectrum of anti-protease activity. Its major physiological role is inhibition of neutrophil elastase in the lungs, and its deficiency is associated with progressive ultimately fatal emphysema. Currently in the US, only plasma-derived human alpha-1-proteinase inhibitor is available for augmentation therapy, which appears to be insufficient to meet the anticipated clinical demand. Moreover, despite effective viral clearance steps in the manufacturing process, the potential risk of contamination with new and unknown pathogens still exists. In response, multiple efforts to develop recombinant versions of human alpha-1-proteinase inhibitor, as an alternative to the plasma-derived protein, have been reported. Over the last two decades, various systems have been used to express the human gene for alpha-1-proteinase inhibitor. This paper reviews the recombinant versions of human alpha-1-proteinase inhibitor produced in various hosts, considers current major safety and efficacy issues regarding recombinant glycoproteins as potential therapeutics, and the factors that are impeding progress in this area(1).

Blood gases at rest and during exercise in patients with alpha1-Pi deficiency

Alpha1-protease inhibitor (Pi) deficiency is associated with a protease-anti-protease imbalance leading to premature destruction of lung tissue and early emphysema. Little is known about the blood gases of these patients in the various stages of the disease. The purpose of this study was to evaluate blood gases in patients with alpha1-Pi deficiency when patients were at rest and during exercise, and to correlate these with lung function measurements. A total of 369 patients with severe alpha1-Pi deficiency had pulmonary function test and blood gas analysis, 282 also had blood gases taken during steady state submaximal exercise testing. Only 21% of the patients had normal blood gases at rest; 71% had mild hypoxaemia; 8% had severe hypoxaemia. Surprisingly, 61% of the patients with mild lung disease and a FEV1 of more than 65% predicted were hypoxaemic. During exercise 65% of the patients had a drop in PO2 of more than 0.40 kPa. FEV1 was a significant predictor for the PO2 values at rest and during exercise. During exercise the arterial-alveolar gradient increased in about 50% and decreased in 25% of the patients. Many patients with alpha1-Pi have blood gas abnormalities. Impaired blood gases in early stages of the disease result in a discrepancy between lung function parameters and blood gases. FEV1 measurements inadequately capture the extent of lung disease in patients with alpha1-Pi deficiency, and both blood gases at rest and during exercise are needed in the assessment of all stages of the disease.

Should health-care systems pay for replacement therapy in patients with alpha(1)-antitrypsin deficiency? A critical review and cost-effectiveness analysis

STUDY OBJECTIVES

Assess cost effectiveness for providing alpha(1)-antitrypsin (alpha(1)-AT) replacement therapy to individuals with severe COPD and alpha(1)-AT deficiency.

MATERIALS AND METHODS

The electronic databases MEDLINE and EMBASE were searched, and relevant bibliographies were reviewed. Effect size, defined as the absolute risk difference between treated and untreated groups, was taken from the highest level of supporting evidence. The cost for providing alpha(1)-AT replacement therapy was analyzed from a payer perspective and was based on Medicare reimbursement rates. Effect size and costs were varied. The year of life saved was discounted up to 7%.

RESULTS

The incremental cost per year of life saved for alpha(1)-AT replacement therapy (60 mg/kg/wk IV) in a 70-kg subject with severe alpha(1)-AT deficiency and an FEV(1) < 50% of predicted based on the National Institutes of Health (NIH) Registry mortality rate data is $13,971. The incremental cost depends substantially on the mortality rate reduction. When the effect size is altered from 10 to 70%, with the cost fixed at $52,000, the incremental cost per year of life saved ranges from $152,941 to $7,330. When effect size is 55% (as in the NIH Registry) but costs are increased almost 300%, from $52,000 to $150,000 per year, then the incremental cost per year of life saved increases from $13,971 to $40,301.

CONCLUSION

No randomized, placebo-controlled trials are available to assess mortality rate reduction with alpha(1)-AT replacement therapy. The best currently available data are observational, from the NIH Registry. Based on these data, alpha(1)-AT replacement therapy is cost-effective in individuals who have severe alpha(1)-AT deficiency and severe COPD.

[Alpha 1-protease inhibitor deficiency. Diagnosis, follow-up and therapy options]

DEFINITION

Alpha-1 antitrypsin (alpha-1 proteinase inhibitor) deficiency is characterized by a marked reduction of alpha-1 antitrypsin, the major antiprotease in man.

PREVALENCE

Alpha-1 antitrypsin deficiency is one of the most common hereditary diseases in Caucasians of European descent. Alpha-1 antitrypsin deficiency is the underlying disorder in approximately 2% of all patients with chronic obstructive pulmonary disease and lung emphysema.

CLINICAL MANIFESTATIONS

Young adults by the age of 30 to 45 years have a high risk for the development of lung emphysema with cough, sputum expectoration and respiratory insufficiency. There is a moderate risk of liver disease.

DIAGNOSTIC PROCEDURES AND TREATMENT

The diagnosis is obtained by measurement of alpha-1 antitrypsin serum levels. Recognition of the disorder is important to prevent deterioration of the pulmonary function by early initiation of preventive measures and treatment. Therapeutic options are physiotherapy, antiobstructive medication and antibiotics. The most direct approach is the intravenous augmentation therapy with purified alpha-1 antitrypsin.

[Usefulness of the quantification of the alpha-1 serous protein band in the screening of alpha-1-antitrypsin deficiency]

BACKGROUND

Population studies indicate that alpha-1-antitrypsin (AAT) deficiency is an under diagnosed disease. Although alpha-1 serum protein is widely known to accompany AAT deficiency, the diagnostic utility of measuring the alpha-1 band to screen for this condition has not been assessed in the literature.

SUBJECTS AND METHOD

Electropherograms with alpha-1 band widths under the reference values were collected over a period of 3 months. The Pi phenotype of AAT was identified for these sera by isoelectric point determination. The phenotypes were compared to those obtained for the population of the same geographic area (n = 440). The alpha-1 band reference values were obtained from 73 healthy individuals with no Pi phenotype deficiency. Moreover, the alpha-1 band was also measured for a group of 17 PiZZ deficient patients.

RESULTS

We analyzed 7,305 electropherograms. One hundred four individuals (1.4%) without hypoproteinemia had alpha-1 readings below reference (set at 2.3%). The phenotypes in this group were 25 PiMM (24%), 52 PiMS (54%), 13 PiMZ (12.5%) and 5 PiSS 5 (5%). The odds ratios (CI 95%) in comparison with the normal population were, respectively, 0.10 (0.16-0.06); 4.58 (2.97-7.04); 4.35 (2.09-9.04) and 5.51 (1.66-18.16) (p < 10-5 in all cases except PiSS, which was p < 0.05). The levels for PiZZ patients were 1.4% +/- 0.3% (range 1.0%-2.1%).

CONCLUSIONS

Three times fewer subjects with a normal PiMM phenotypes are found among individuals with low alpha-1 band serum protein levels, and many more of such individuals are carriers of Z allele heterozygotes. Alpha-1 band readings in patients with AAT deficiency (PiZZ phenotype) have alpha-1 values below reference. Measuring alpha-1 protein is an easy technique, within the expertise of any laboratory, and may be very useful for screening for AAT deficiency in patients with chronic respiratory diseases.

Usefulness of a national registry of alpha-1-antitrypsin deficiency. The Spanish experience

Severe alpha-1-antitrypsin (AAT) deficiency, phenotype Pi ZZ, is a rare condition with an estimated prevalence of 1/4500 individuals in Spain. Given this low prevalence, it seems useful to accumulate all the information derived from the care of these patients. In this context, the Spanish Registry of patients with AAT deficiency was founded in 1993; its main objectives were to establish guidelines adapted to our country for the treatment and management of AAT-deficient patients, offer expert support to physicians all over the country treating these patients, and provide technical support on the determination of Pi phenotyping and genotyping of individuals suspected of being AAT-deficient. From 1993 to January 1998 the number of enrollees increased from 48 to 223, of which 216 were Pi ZZ. Seventy-three per cent were male and only 31.5% were never smokers, mean age was 46 years (SD = 13 years) and mean FEV1 53% predicted (SD = 31%). 83% were index cases who, compared with non-index cases, were older (49 +/- 11 vs. 35 +/- 13 years, P < 0.001), more likely to have a smoking history (85% vs. 47%, P < 0.01) and displayed more severe impairment in pulmonary function (FEV1% = 40% +/- 19% vs. 96% +/- 23%, P < 0.001). Augmentation therapy was administered to 129 patients (58%). Treated patients had more severe impairment in pulmonary function than the untreated (FEV1% = 40% +/- 21% vs. 72% +/- 32%, P < 0.001) and were more likely to be index cases (81% vs. 43%, P < 0.001). Characteristics of the patients included are similar to those described for other Registries. The Registry has extended knowledge of the disease throughout the country and has established local guidelines for treatment and follow-up. It may be a valid database for future co-operation in international initiatives.

Current issues in the management of chronic obstructive pulmonary diseases

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality, especially among smokers. Many guidelines that have recently been issued emphasize that COPD is not inaccessible to therapeutic measures: although few interventions are capable of affecting its natural history (i.e. smoking cessation and, in patients with severe resting hypoxaemia, oxygen therapy), several others have a demonstrated effect on symptoms and, thereby, quality of life. The effects of inhaled corticosteroids, and alpha 1-antitrypsin replacement therapy in emphysema due to alpha 1-antitrypsin deficiency are currently being studied. When there is a marked increase in mucus production, chest physiotherapy using controlled expiration and directed cough may be useful. Inhaled bronchodilators are frequently effective on dyspnoea, anticholinergic agents being more suitable for continuous symptoms. Rehabilitation, which includes education and psychosocial care, chest physiotherapy, nutritional care and exercise training, also improves quality of life. When there is persistent severe alveolar hypoventilation despite oxygen therapy, long-term mechanical ventilation may be considered. Surgical options in the treatment of emphysema include resection of giant bullae and lung volume reduction surgery. Lung transplantation should be proposed only in patients with end-stage disease, the difficulty here being to define what 'end-stage' means. Finally, all preventive and some therapeutic interventions are likely to be more effective early in the course of the disease. Thus, efforts should be made to detect airways obstruction early in subjects at risk, such as smokers.

Is screening for chronic obstructive pulmonary disease justified?

BACKGROUND

Many experts recommend spirometry to screen for chronic obstructive pulmonary disease (COPD) in asymptomatic patients; however, evidence for this recommendation has not been systematically reviewed.

METHODS

We examined whether screening spirometry meets standard criteria for effective screening. We performed structured searches of MEDLINE, followed by a selective search of the CITATION index, to locate randomized trials of interventions for asymptomatic patients with COPD. In regard to smoking cessation, we included all controlled trials of smoking cessation programs that used spirometry. We also included all studies that assessed the ability of spirometry to predict successful smoking cessation by comparing baseline lung function in smokers who subsequently quit versus those who did not.

RESULTS

With the exception of smoking cessation, all interventions for COPD have only been proven effective in symptomatic patients. Two studies found that multifaceted smoking cessation programs that included spirometry were efficacious. There was no effect in a third study that isolated the role of spirometry. Smokers with abnormal spirometric results are less likely than other smokers to quit over the ensuing year.

CONCLUSIONS

There is no evidence that spirometry, as an isolated intervention, aids smoking cessation.

Intravenous alpha-1-antitrypsin replacement therapy: case report after one year of treatment

Alpha-1-antitrypsin deficiency is an autosomally inherited disease in which individuals homozygous for the disorder are prone to develop severe emphysema. We report the case of a 43 yr old man with severe deficiency and advanced emphysema and the first experience in Ireland with intravenous alpha-1-antitrypsin replacement. After 1 yr of replacement therapy we report our experience with dosage and frequency of infusion as well as pulmonary function test data before and during treatment.