Recombinant Alpha-1-antitrypsin
Also known as: AAT augmentation therapy (recombinant), Alpha-1-proteinase inhibitor (recombinant), Alpha‑1‑antitrypsin, rAAT, recombinant AAT, Recombinant human alpha‑1‑antitrypsin, rhA1AT, SERPINA1, SERPINA1 recombinant protein
Source Recombinant Alpha-1-antitrypsin at Peptiology
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Summary
Recombinant alpha‑1‑antitrypsin (rAAT) is a laboratory‑produced version of the serpin protein that normally inhibits neutrophil elastase. It is being investigated as a replacement therapy for individuals with alpha‑1‑antitrypsin deficiency, a genetic condition that predisposes to emphysema, bronchiectasis, and, in some studies, cystic fibrosis‑related lung damage. Current research explores intravenous infusion of an AAT‑Fc fusion (INBRX‑101) and inhaled delivery, including a novel dry‑powder formulation, as alternatives to plasma‑derived AAT infusions.
Mechanism of Action
Alpha‑1‑antitrypsin is a serine protease inhibitor (serpin) that forms a covalent complex with neutrophil elastase and related proteases, blocking their ability to degrade elastin and other extracellular‑matrix proteins. By neutralising elastase activity, AAT protects alveolar walls and airway structures from inflammatory damage. Recombinant forms retain this inhibitory activity, and the Fc‑fusion design of INBRX‑101 prolongs circulating half‑life through neonatal Fc‑receptor recycling, allowing sustained functional AAT levels in blood and lung lining fluid.
What the Research Shows
Early‑phase investigations have demonstrated the feasibility of producing active, endotoxin‑free rAAT in bacterial systems and formulating it as a respirable dry powder for inhalation (Pharmaceutics 2022). A phase‑1 dose‑escalation study of the recombinant AAT‑Fc fusion INBRX‑101 (2024) showed dose‑dependent increases in serum functional AAT, maintenance of target levels (>21 µM) for up to four weeks, and detection of the protein in pulmonary epithelial lining fluid, with a favorable safety profile. A pilot double‑blind, randomized trial in cystic fibrosis (2006) reported that nebulized rAAT was well tolerated and produced trends toward reduced neutrophil elastase activity and lower inflammatory markers, though primary efficacy endpoints were not met. Additional reviews and formulation studies (1991, 1993, 2010) discuss production methods, stability, and the therapeutic rationale for recombinant replacement.
Reported Benefits
Recombinant AAT offers a pathogen‑free source of functional inhibitor, potentially alleviating supply constraints of plasma‑derived product. Early clinical data indicate that intravenous INBRX‑101 can sustain therapeutic AAT concentrations with extended dosing intervals, reducing infusion frequency. Inhaled rAAT appears safe and may lower neutrophil elastase activity and inflammatory mediators in cystic fibrosis, suggesting a direct lung‑targeted benefit. The dry‑powder approach could further simplify administration and improve patient adherence.
Limitations of the Evidence
Evidence remains limited to phase‑1 and small pilot studies; long‑term clinical outcomes, such as slowing emphysema progression, have not been demonstrated. The inhaled CF trial did not achieve statistically significant reductions in elastase activity, indicating modest efficacy. Production scalability, oxidation‑related loss of activity, and the need for oxygen‑free handling are technical challenges. No regulatory approval for recombinant AAT formulations exists, and comparative effectiveness versus plasma‑derived AAT is still unknown.
Safety Considerations
Across studies, recombinant AAT was well tolerated. The phase‑1 INBRX‑101 trial reported only grade ≤ 2 adverse events, with no serious safety signals and no impact of anti‑drug antibodies on pharmacokinetics. The cystic fibrosis inhalation trial observed no major adverse events or allergic reactions. Formulation considerations, such as protecting methionine residues from oxidation, are important to preserve activity. As with any protein therapeutic, monitoring for immunogenicity is advisable.
How It Is Administered
Recombinant AAT is being investigated for intravenous infusion (e.g., INBRX‑101) and for pulmonary delivery via nebulization or dry‑powder inhalation. The dry‑powder formulation utilizes L‑leucine and mannitol as excipients to achieve respirable particle size and protect protein stability. Inhaled studies employed once‑daily nebulized doses, while the IV study used doses every three weeks. No specific dosing regimens are established for clinical use.
Routes of Administration
Goals & Uses
- Type 1 diabetes / islet protectionMetabolic/autoimmune DiseaseLow
- Lung inflammation and emphysema preventionPulmonaryModerate
- Reduce liver fibrosis in A1AT deficiencyHepaticLow
- Graft-versus-host disease (GvHD) prevention/treatmentImmunomodulationModerate
- Alpha-1-antitrypsin deficiency (AATD) augmentationGenetic/metabolic DiseaseModerate
- Prevent progression of emphysema in A1AT deficiencyPulmonaryModerate
- Inflammatory bowel diseaseGastroenterologyLow
Contraindications
- Hypersensitivity to AAT or excipientsAllergy/immunologyHigh
- IgA deficiency with anti-IgA antibodiesImmunologicalModerate
- Active malignancy requiring immunosuppression cautionOncologyModerate
- Known hypersensitivity to recombinant A1AT or any excipientAllergyHigh
- Severe congestive heart failureCardiovascularModerate
Adverse Effects
- AnaphylaxisImmunologicRareSevere life-threatening allergic reaction
- HeadacheNeurologicUncommonPain in the head or upper neck
- NauseaGastrointestinalUncommonFeeling of sickness or urge to vomit
- Infusion‑related reactions (e.g., flushing, rash)GeneralCommon
- Elevated liver enzymesHepaticRareIncrease in AST/ALT or other hepatic markers
- Infusion-related reactionsHypersensitivityUncommon
- DizzinessNeurologicUncommonFeeling faint, lightheaded, or unsteady
- Immunogenicity / antibody formationImmunologicUnknown
Drug Interactions
- Other protease inhibitorsModerate
- Immunosuppressants (e.g., corticosteroids, tacrolimus)Moderate
Population Constraints
- PregnancyReproductive SafetyRelative
- Pediatric patientsAgeRelative
- Pregnant womenReproductiveRelative
- Renal or hepatic impairmentOrgan DysfunctionRelative
Regulatory Status
- European UnionInvestigationalPhase III trials ongoing.
- United StatesInvestigationalUnder IND for A1AT deficiency.
- United KingdomInvestigationalClinical trials authorized.
Plasma-derived AAT products are FDA-approved for AATD; recombinant forms (e.g., produced in yeast, CHO cells, or transgenic systems) are investigational. No rAAT product has received FDA or EMA approval as of the knowledge cutoff. Orphan drug designation has been sought for some rAAT programs.
Evidence & Sources
- Journal ArticleLowBianchera A, et al.2022-01-01T00:00:00.000000Z
- Journal ArticleModerateTarján E, Pitlik E1991-01-01T00:00:00.000000Z
- Journal ArticleLowBrantly ML, et al.2024-01-01T00:00:00.000000Z
- Journal ArticleUngradedKabziński J, Kedziora J, Majsterek I2010-01-01T00:00:00.000000Z
- Journal ArticleModerateMartin SL, et al.2006-01-01T00:00:00.000000Z
- Journal ArticleModerateVemuri S, Yu CT, Roosdorp N1993-01-01T00:00:00.000000Z
Frequently Asked Questions
What condition is recombinant alpha‑1‑antitrypsin intended to treat?
It is being developed as a replacement therapy for alpha‑1‑antitrypsin deficiency, a genetic disorder that increases risk of lung diseases such as emphysema and bronchiectasis, and is also being explored for inflammatory lung conditions like cystic fibrosis.
How does the recombinant AAT‑Fc fusion differ from regular AAT?
The Fc portion is attached to the AAT molecule, enabling recycling via the neonatal Fc receptor, which extends the protein’s circulating half‑life and allows less frequent dosing while maintaining therapeutic serum levels.
Is recombinant AAT currently approved for clinical use?
No. All recombinant formulations described in the literature remain investigational, with data limited to early‑phase clinical trials and formulation studies.
What are the main safety concerns with recombinant AAT?
Studies to date have reported only mild adverse events and no serious allergic reactions. Immunogenicity has been monitored, and anti‑drug antibodies observed did not affect drug exposure. Oxidative degradation of the protein is a formulation concern.
Can recombinant AAT be inhaled instead of given by infusion?
Yes. Pilot trials have delivered rAAT by nebulization and a recent proof‑of‑concept study produced a dry‑powder suitable for inhalation. Inhaled delivery aims to target the lung directly, but efficacy data are still preliminary.
What is Recombinant Alpha-1-antitrypsin?
Recombinant alpha‑1‑antitrypsin (rAAT) is a laboratory‑produced version of the serpin protein that normally inhibits neutrophil elastase. It is being investigated as a replacement therapy for individuals with alpha‑1‑antitrypsin deficiency, a genetic condition that predisposes to emphysema, bronchiectasis, and, in some studies, cystic fibrosis‑related lung damage. Current research explores intravenous infusion of an AAT‑Fc fusion (INBRX‑101) and inhaled delivery, including a novel dry‑powder formulation, as alternatives to plasma‑derived AAT infusions.
What is Recombinant Alpha-1-antitrypsin used for?
Recombinant Alpha-1-antitrypsin is educationally associated with: Type 1 diabetes / islet protection, Lung inflammation and emphysema prevention, Reduce liver fibrosis in A1AT deficiency, Graft-versus-host disease (GvHD) prevention/treatment, Alpha-1-antitrypsin deficiency (AATD) augmentation, Prevent progression of emphysema in A1AT deficiency, Inflammatory bowel disease. Educational only — not medical advice.
How is Recombinant Alpha-1-antitrypsin administered?
Recorded routes of administration: Inhaled, Intravenous, Subcutaneous.
What are the potential side effects of Recombinant Alpha-1-antitrypsin?
Reported adverse effects include: Anaphylaxis, Headache, Nausea, Infusion‑related reactions (e.g., flushing, rash), Elevated liver enzymes, Infusion-related reactions, Dizziness, Immunogenicity / antibody formation. This list is not exhaustive — consult a qualified clinician.
Who should avoid Recombinant Alpha-1-antitrypsin?
Recorded contraindications: Hypersensitivity to AAT or excipients, IgA deficiency with anti-IgA antibodies, Active malignancy requiring immunosuppression caution, Known hypersensitivity to recombinant A1AT or any excipient, Severe congestive heart failure. Consult a qualified clinician before use.