Robert A. Sandhaus

Phase 2 Clinical Trial of a Recombinant Adeno-Associated Viral Vector Expressing α1-Antitrypsin: Interim Results

Recombinant adeno-associated virus (rAAV) vectors offer promise for the gene therapy of α(1)-antitrypsin (AAT) deficiency. In our prior trial, an rAAV vector expressing human AAT (rAAV1-CB-hAAT) provided sustained, vector-derived AAT expression for >1 year. In the current phase 2 clinical trial, this same vector, produced by a herpes simplex virus complementation method, was administered to nine AAT-deficient individuals by intramuscular injection at doses of 6.0×10(11), 1.9×10(12), and 6.0×10(12) vector genomes/kg (n=3 subjects/dose). Vector-derived expression of normal (M-type) AAT in serum was dose dependent, peaked on day 30, and persisted for at least 90 days. Vector administration was well tolerated, with only mild injection site reactions and no serious adverse events. Serum creatine kinase was transiently elevated on day 30 in five of six subjects in the two higher dose groups and normalized by day 45. As expected, all subjects developed anti-AAV antibodies and interferon-γ enzyme-linked immunospot responses to AAV peptides, and no subjects developed antibodies to AAT. One subject in the mid-dose group developed T cell responses to a single AAT peptide unassociated with any clinical effects. Muscle biopsies obtained on day 90 showed strong immunostaining for AAT and moderate to marked inflammatory cell infiltrates composed primarily of CD3-reactive T lymphocytes that were primarily of the CD8(+) subtype. These results support the feasibility and safety of AAV gene therapy for AAT deficiency, and indicate that serum levels of vector-derived normal human AAT >20 μg/ml can be achieved. However, further improvements in the design or delivery of rAAV-AAT vectors will be required to achieve therapeutic target serum AAT concentrations.

Intravenous augmentation treatment and lung density in severe α1 antitrypsin deficiency (RAPID): a randomised, double-blind, placebo-controlled trial.

BACKGROUND The efficacy of α1 proteinase inhibitor (A1PI) augmentation treatment for α1 antitrypsin deficiency has not been substantiated by a randomised, placebo-controlled trial. CT-measured lung density is a more sensitive measure of disease progression in α1 antitrypsin deficiency emphysema than spirometry is, so we aimed to assess the efficacy of augmentation treatment with this measure. METHODS The RAPID study was a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial of A1PI treatment in patients with α1 antitrypsin deficiency. We recruited eligible non-smokers (aged 18-65 years) in 28 international study centres in 13 countries if they had severe α1 antitrypsin deficiency (serum concentration <11 μM) with a forced expiratory volume in 1 s of 35-70% (predicted). We excluded patients if they had undergone, or were on the waiting list to undergo, lung transplantation, lobectomy, or lung volume-reduction surgery, or had selective IgA deficiency. We randomly assigned patients (1:1; done by Accovion) using a computerised pseudorandom number generator (block size of four) with centre stratification to receive A1PI intravenously 60 mg/kg per week or placebo for 24 months. All patients and study investigators (including those assessing outcomes) were unaware of treatment allocation throughout the study. Primary endpoints were CT lung density at total lung capacity (TLC) and functional residual capacity (FRC) combined, and the two separately, at 0, 3, 12, 21, and 24 months, analysed by modified intention to treat (patients needed at least one evaluable lung density measurement). This study is registered with ClinicalTrials.gov, number NCT00261833. A 2-year open-label extension study was also completed (NCT00670007). FINDINGS Between March 1, 2006, and Nov 3, 2010, we randomly allocated 93 (52%) patients A1PI and 87 (48%) placebo, analysing 92 in the A1PI group and 85 in the placebo group. The annual rate of lung density loss at TLC and FRC combined did not differ between groups (A1PI -1·50 g/L per year [SE 0·22]; placebo -2·12 g/L per year [0·24]; difference 0·62 g/L per year [95% CI -0·02 to 1·26], p=0·06). However, the annual rate of lung density loss at TLC alone was significantly less in patients in the A1PI group (-1·45 g/L per year [SE 0·23]) than in the placebo group (-2·19 g/L per year [0·25]; difference 0·74 g/L per year [95% CI 0·06-1·42], p=0·03), but was not at FRC alone (A1PI -1·54 g/L per year [0·24]; placebo -2·02 g/L per year [0·26]; difference 0·48 g/L per year [-0·22 to 1·18], p=0·18). Treatment-emergent adverse events were similar between groups, with 1298 occurring in 92 (99%) patients in the A1PI group and 1068 occuring in 86 (99%) in the placebo group. 71 severe treatment-emergent adverse events occurred in 25 (27%) patients in the A1PI group and 58 occurred in 27 (31%) in the placebo group. One treatment-emergent adverse event leading to withdrawal from the study occurred in one patient (1%) in the A1PI group and ten occurred in four (5%) in the placebo group. One death occurred in the A1PI group (respiratory failure) and three occurred in the placebo group (sepsis, pneumonia, and metastatic breast cancer). INTERPRETATION Measurement of lung density with CT at TLC alone provides evidence that purified A1PI augmentation slows progression of emphysema, a finding that could not be substantiated by lung density measurement at FRC alone or by the two measurements combined. These findings should prompt consideration of augmentation treatment to preserve lung parenchyma in individuals with emphysema secondary to severe α1 antitrypsin deficiency. FUNDING CSL Behring.

A combined pulmonary -radiology workshop for visual evaluation of COPD: study design, chest CT findings and concordance with quantitative evaluation

Abstract The purposes of this study were: to describe chest CT findings in normal non-smoking controls and cigarette smokers with and without COPD; to compare the prevalence of CT abnormalities with severity of COPD; and to evaluate concordance between visual and quantitative chest CT (QCT) scoring. Methods: Volumetric inspiratory and expiratory CT scans of 294 subjects, including normal non-smokers, smokers without COPD, and smokers with GOLD Stage I-IV COPD, were scored at a multi-reader workshop using a standardized worksheet. There were 58 observers (33 pulmonologists, 25 radiologists); each scan was scored by 9–11 observers. Interobserver agreement was calculated using kappa statistic. Median score of visual observations was compared with QCT measurements. Results: Interobserver agreement was moderate for the presence or absence of emphysema and for the presence of panlobular emphysema; fair for the presence of centrilobular, paraseptal, and bullous emphysema subtypes and for the presence of bronchial wall thickening; and poor for gas trapping, centrilobular nodularity, mosaic attenuation, and bronchial dilation. Agreement was similar for radiologists and pulmonologists. The prevalence on CT readings of most abnormalities (e.g. emphysema, bronchial wall thickening, mosaic attenuation, expiratory gas trapping) increased significantly with greater COPD severity, while the prevalence of centrilobular nodularity decreased. Concordances between visual scoring and quantitative scoring of emphysema, gas trapping and airway wall thickening were 75%, 87% and 65%, respectively. Conclusions: Despite substantial inter-observer variation, visual assessment of chest CT scans in cigarette smokers provides information regarding lung disease severity; visual scoring may be complementary to quantitative evaluation.

Augmentation Therapy With α1-Antitrypsin: Patterns of Use and Adverse Events

Study objectives: To describe patterns of prescribing augmentation therapy, and types and rates of adverse events in the National Heart, Lung, and Blood Institute Registry for Individuals with Severe Deficiency of Alpha 1 -Antitrypsin. Design: Observational cohort study with follow-up visits every 6 to 12 months for up to 7 years. Measurements: The rate and dosing frequency with which Registry participants were prescribed to receive augmentation therapy by their managing physicians, and the type and frequency of adverse events, classified in two ways: severity of self-reported symptoms, and actions taken as a consequence of the symptom. Results: Over the course of Registry follow-up, 66% (n = 747) of the participants received augmentation therapy at some time. In keeping with recommendations made in the 1989 American Thoracic Society (ATS) statement, 75% of participants with airflow obstruction at first visit (defined as FEV 1 1 ≥ 80% predicted (14%) also received augmentation therapy. Among those with COPD for whom augmentation therapy was not prescribed, financial constraints were the reported cause in 30%. Observed patterns also varied from approved practice, in that dosing frequencies other than the US Food and Drug Administration-approved, once-weekly regimen were frequently prescribed. The overall rate of reported adverse events was 0.02 per patient-month, with 83% of participants reporting no events. This overall rate was composed of 16% considered mild events, 76% moderate events, and 9% severe events. Conclusions: We conclude that augmentation therapy was generally well tolerated and, consistent with ATS guidelines, physicians generally did not prescribe augmentation therapy for subjects with FEV 1 ≥ 80% predicted. However, the large percentage of subjects with FEV 1

Human Treg responses allow sustained recombinant adeno-associated virus–mediated transgene expression

Recombinant adeno-associated virus (rAAV) vectors have shown promise for the treatment of several diseases; however, immune-mediated elimination of transduced cells has been suggested to limit and account for a loss of efficacy. To determine whether rAAV vector expression can persist long term, we administered rAAV vectors expressing normal, M-type α-1 antitrypsin (M-AAT) to AAT-deficient subjects at various doses by multiple i.m. injections. M-specific AAT expression was observed in all subjects in a dose-dependent manner and was sustained for more than 1 year in the absence of immune suppression. Muscle biopsies at 1 year had sustained AAT expression and a reduction of inflammatory cells compared with 3 month biopsies. Deep sequencing of the TCR Vβ region from muscle biopsies demonstrated a limited number of T cell clones that emerged at 3 months after vector administration and persisted for 1 year. In situ immunophenotyping revealed a substantial Treg population in muscle biopsy samples containing AAT-expressing myofibers. Approximately 10% of all T cells in muscle were natural Tregs, which were activated in response to AAV capsid. These results suggest that i.m. delivery of rAAV type 1-AAT (rAAV1-AAT) induces a T regulatory response that allows ongoing transgene expression and indicates that immunomodulatory treatments may not be necessary for rAAV-mediated gene therapy.

Determinants of Airflow Obstruction in Severe Alpha 1- Antitrypsin Deficiency

Background: Severe α1-antitrypsin (AAT) deficiency is an autosomal recessive genetic condition associated with an increased but variable risk for chronic obstructive pulmonary disease (COPD). A study was undertaken to assess the impact of chronic bronchitis, pneumonia, asthma and sex on the development of COPD in individuals with severe AAT deficiency. Methods: The AAT Genetic Modifier Study is a multicentre family-based cohort study designed to study the genetic and epidemiological determinants of COPD in AAT deficiency. 378 individuals (age range 33–80 years), confirmed to be homozygous for the SERPINA1 Z mutation, were included in the analyses. The primary outcomes of interest were a quantitative outcome, forced expiratory volume in 1 s (FEV1) percentage predicted, and a qualitative outcome, severe airflow obstruction (FEV1 <50% predicted). Results: In multivariate analysis of the overall cohort, cigarette smoking, sex, asthma, chronic bronchitis and pneumonia were risk factors for reduced FEV1 percentage predicted and severe airflow obstruction (p<0.01). Index cases had lower FEV1 values, higher smoking histories and more reports of adult asthma, pneumonia and asthma before age 16 than non-index cases (p<0.01). Men had lower pre- and post-bronchodilator FEV1 percentage predicted than women (p<0.0001); the lowest FEV1 values were observed in men reporting a history of childhood asthma (26.9%). This trend for more severe obstruction in men remained when index and non-index groups were examined separately, with men representing the majority of non-index individuals with airflow obstruction (71%). Chronic bronchitis (OR 3.8, CI 1.8 to 12.0) and a physician’s report of asthma (OR 4.2, CI 1.4 to 13.1) were predictors of severe airflow obstruction in multivariate analysis of non-index men but not women. Conclusion: In individuals with severe AAT deficiency, sex, asthma, chronic bronchitis and pneumonia are risk factors for severe COPD, in addition to cigarette smoking. These results suggest that, in subjects severely deficient in AAT, men, individuals with symptoms of chronic bronchitis and/or a past diagnosis of asthma or pneumonia may benefit from closer monitoring and potentially earlier treatment.

Neutrophil Elastase-Mediated Lung Disease

Abstract Elastases of both the neutrophil and macrophage have been implicated in lung disease initiation and progression. Although it is unlikely that these proteases evolved for the purpose of injuring lung tissue, the elastin-rich connective tissue framework of the lungs appears to be particularly susceptible to the action of elastolytic proteases. Assuming that neutrophil elastase most likely plays a role in the migration of neutrophils toward a site of inflammation and degradation of proteins from invading organisms or other products of the inflammatory response, it is the role of inhibitors of this protease to protect normal tissues from its effects. In alpha-1 antitrypsin deficiency we find an experiment of nature that disrupts this protease-anti-protease balance, resulting in an increased risk of destructive lung disease.

Clinical InvestigationsANTITRYPSINAugmentation Therapy With α1-Antitrypsin: Patterns of Use and Adverse Events

Study objectives: To describe patterns of prescribing augmentation therapy, and types and rates of adverse events in the National Heart, Lung, and Blood Institute Registry for Individuals with Severe Deficiency of Alpha 1 -Antitrypsin. Design: Observational cohort study with follow-up visits every 6 to 12 months for up to 7 years. Measurements: The rate and dosing frequency with which Registry participants were prescribed to receive augmentation therapy by their managing physicians, and the type and frequency of adverse events, classified in two ways: severity of self-reported symptoms, and actions taken as a consequence of the symptom. Results: Over the course of Registry follow-up, 66% (n = 747) of the participants received augmentation therapy at some time. In keeping with recommendations made in the 1989 American Thoracic Society (ATS) statement, 75% of participants with airflow obstruction at first visit (defined as FEV 1 1 ≥ 80% predicted (14%) also received augmentation therapy. Among those with COPD for whom augmentation therapy was not prescribed, financial constraints were the reported cause in 30%. Observed patterns also varied from approved practice, in that dosing frequencies other than the US Food and Drug Administration-approved, once-weekly regimen were frequently prescribed. The overall rate of reported adverse events was 0.02 per patient-month, with 83% of participants reporting no events. This overall rate was composed of 16% considered mild events, 76% moderate events, and 9% severe events. Conclusions: We conclude that augmentation therapy was generally well tolerated and, consistent with ATS guidelines, physicians generally did not prescribe augmentation therapy for subjects with FEV 1 ≥ 80% predicted. However, the large percentage of subjects with FEV 1

Results of a Survey of Patients with Alpha-1 Antitrypsin Deficiency

Background: α1-Antitrypsin deficiency (AATD) is an uncommon genetic disease which occurs in 1–2.5% of Americans with chronic obstructive pulmonary disease (COPD). Little is known about current demographics of AATD. Objectives: This survey study reviews the clinical characteristics of diseased individuals in North America. Methods: A survey of members from the mailing lists of US AATD patient support organizations was commissioned with duplicate persons omitted. The survey was mailed to 5,222 unique individuals with AATD. Questionnaires were returned by 1,953 individuals, including 1,810 with severe deficiency, 93 with the carrier state and 41 who were caregivers of others. Results: The majority (81%) of participants reported COPD with symptoms of asthma, chronic bronchitis, and emphysema, usually in combination. The mean age of respondents [53.1 ± 13.2 (SD) years] is older than the general US population. Lung or liver transplantation was reported by 9% of all respondents (n = 175), including 66 single lung transplants, 68 double lung transplants, and 47 liver transplants. Another 6.6% (n = 128) reported that they were currently on a transplant list. Twenty-one percent of lung transplants report continuing augmentation therapy use. Augmentation use is reported by 75% of those with obstructive lung disease. The majority of patients with liver disease also have COPD. Conclusions: AATD remains a devastating illness for many of those affected as reflected in a high incidence of transplantation for liver and lung disease.

Multi-Center Study: The Biochemical Efficacy, Safety and Tolerability of a New α1-Proteinase Inhibitor, Zemaira

Augmentation therapy with a plasma derived α1-Proteinase Inhibitor (α1-PI) has been demonstrated to be effective in restoring serum Alpha1-antitrypsin (AAT)* levels in individuals with AAT Deficiency (note: α1 PI and AAT are synonymous). The objective of this study was to demonstrate that the steady-state trough serum α1-PI levels, achieved by a new plasma derived α1-PI (Zemaira, study drug, ZLB Behring LLC, King of Prussia, Pennsylvania, USA), were bioequivalent to those achieved by the currently available α1-PI therapy, Prolastin (control drug, Bayer Corporation, Berkeley, California, USA), and maintained weekly trough serum antigenic α1-PI levels above the protective threshold of 11 μ M. This multi-center, controlled study randomized a total of 44 subjects to receive either study or control drug for a 10-week double-blind phase. The control group was then crossed over to receive the study drug for the remainder of the study (14 weeks). The difference in mean trough serum antigenic α1-PI level between the treatment groups was 1.45 μ M (90% CI-2.77, −0.13), signifying bioequivalence. The mean trough serum antigenic α1-PI level in the study drug group was greater than the therapeutic threshold of 11 μ M, achieving a level of 17.7 μ M during the steady-state period. Treatment-related adverse events (AEs) were seen in 7% and 21% of study and control drug treated subjects, respectively. No documented viral transmission occurred. These results demonstrate that the new plasma derived α1-PI (Zemaira) is bioequivalent to the currently available product Prolastin, is well tolerated, and safe with respect to the risk of viral transmission.