Clinical characterization of a novel alpha1-antitrypsin null variant: PiQ0Heidelberg

An Alpha-1 Antitrypsin Deficiency Screening Study in Patients with Chronic Obstructive Pulmonary Disease, Bronchiectasis, or Asthma in Turkey

Purpose

Alpha-1 antitrypsin deficiency (AATD) is a rare hereditary condition characterized by decreased serum alpha-1 antitrypsin (AAT) levels. We aim to identify AATD in patients with chronic obstructive pulmonary disease (COPD), bronchiectasis, or asthma and to report the frequency of AAT variants in Turkey.

Patients and Methods

This non-interventional, multicenter, prospective study was conducted between October 2021 and June 2022. Adult patients with COPD, bronchiectasis, asthma, liver symptoms, or family members with AATD were included. Demographic and clinical characteristics, pulmonary diagnosis, respiratory symptoms, and AAT serum levels were assessed. Whole blood samples were collected as dried blood spots, and the most common AATD mutations were simultaneously tested by allele-specific genotyping.

Results

A total of 1088 patients, mainly diagnosed with COPD (92.7%) and shortness of breath (78.7%), were assessed. Fifty-one (5%) were found to have AATD mutations. Fifteen (29.4%) patients had Pi*S or Pi*Z mutations, whereas 36 (70.6%) patients carried rare alleles Pi*M malton (n=18, 35.3% of mutations), Pi*I (n=8, 16%), Pi*P lowell (n=7, 14%), Pi*M heerlen (n=2, 4%), and Pi*S iiyama (n=1, 2%). The most common heterozygous combinations were Pi*M/Z (n=12, 24%), and Pi*M/M malton (n=11, 22%). Ten patients with severe AATD due to two deficiency alleles were identified, two with the Pi*Z/Z genotype, four with the genotype Pi*M malton/M malton, three with Pi*Z/M malton, and one with Pi*Z/M heerlen.

Conclusion

Our results identified AATD mutations as a genetic-based contributor to lung disease in patients with COPD or bronchiectasis and assessed their frequency in a population of Turkish patients.

Diagnosis and augmentation therapy for alpha-1 antitrypsin deficiency: current knowledge and future potential

The underdiagnosis of alpha-1 antitrypsin (AAT) deficiency (AATD) has been recognized for many years, yet little progress has been made in treatment of the disease. In this review, we summarize the AATD disease process as well as its diagnosis and treatment by AAT augmentation therapy. AATD is a rare autosomal disease that primarily affects the lungs and liver. AATD is associated with an increased susceptibility to developing pulmonary emphysema. The specific pharmacological treatment for AATD is intravenous administration of exogenous AAT. Augmentation therapy with AAT increases serum and pulmonary epithelial AAT levels, restores anti-elastase capacity, and decreases inflammatory mediators in the lung. Augmentation therapy reduces the loss of lung density over time, thus slowing progression of the disease. The effects of augmentation therapy on outcomes, such as frequency/duration of flare-ups, quality of life, lung function decline and mortality, are assessed. Wider testing for AATD, potentially through primary care physicians, could result in earlier treatment and better outcomes for individuals with AATD-induced lung respiratory disease.

Orphan drug development in alpha-1 antitypsin deficiency

Alpha-1 antitrypsin deficiency (AATD, OMIM #613490) is a rare metabolic disorder affecting lungs and liver. The purpose of this study is to assess the impact of the US orphan drug act on AATD by providing a quantitative clinical-regulatory insight into the status of FDA orphan drug approvals and designations for compounds intended to treat AATD. This is across-sectional analysis of the FDA database for orphan drug designations. Primary endpoint: orphan drug approvals. Secondary endpoint: orphan drug designations by the FDA. Close of database was 16 July 2021. STROBE criteria were respected. Primary outcome: one compound, alpha-1-proteinase inhibitor (human) was approved as an orphan drug in 1987 with market exclusivity until 1994. Secondary outcome: sixteen compounds received FDA orphan drug designation including protein, anti-inflammatory, mucolytic, gene, or cell therapy. Drug development activities in AATD were comparable to other rare conditions and led to the FDA-approval of one compound, based on a relatively simple technological platform. The current unmet medical need to be addressed are extrapulmonary manifestations, in this case the AATD-associated liver disease. Orphan drug development is actually focusing on (1) diversified recombinant AAT production platforms, and (2) innovative gene therapies, which may encompass a more holistic therapeutic approach.