SBIR-STTR Award

LEXEO Therapeutics, LLC, is an early stage biotechnology company focused on using gene therapy technologies to protect vulnerable organs from oxidant stress. LEX01, the 1st LEXEO product, is a 1st in class, next generation gene therapy treatment for alpha 1-antitrypsin (AAT) deficiency, an autosomal recessive hereditary disorder associated with low serum levels of AAT. AAT (SERPINA1), a 52 kDa serine antiprotease produced by the liver, protects the lung from proteolytic enzymes released by inflammatory cells. In AAT deficiency, the lung is vulnerable to destruction by proteolytic enzymes released by inflam- matory cells that degrade the lung, resulting in emphysema. AAT deficiency is currently treated with weekly infusions of AAT purified from pooled human plasma. Gene therapy for AAT deficiency holds the promise that a single administration will generate sufficient amounts of AAT to protect the lung on a persis- tent basis, obviating weekly AAT protein therapy. First generation gene therapy strategies are under de- velopment to treat AAT deficiency using adenoassociated virus (AAV) gene transfer vectors to deliver the human AAT coding sequence in vivo by various routes. The Achilles heel of these strategies is the sensi- tivity of the AAT molecule to oxidants. The active site of human AAT includes Met358, with a 2° contribu- tion by Met351. When oxidized (e.g., by cigarette smoke, inflammatory cell products, ambient pollution), AAT is rendered ineffective and cannot inhibit neutrophil elastase, its primary target. LEX01, designed as an AAV vector coding for an elastase-inhibiting, oxidation-resistant human AAT, solves this prob- lem with substitution at Met358 and/or Met351 with Val or Leu to render the AAT molecule oxidation re- sistant, yet maintaining its function as an anti-elastase. This is a Fast Track application with the goal of be- ing clinical trial-ready within 3 yr. Successful completion of these aims will make LEXEO attractive for biotech, pharma and/or venture investment. Phase I, Aim 1. Using the normal M1(A213) AAT coding sequence as a base, assess combinations of Met, Leu and Val at positions 351 and 358 to determine the optimal neutrophil elastase inhibiting, oxidation resistant form of AAT to use in LEX01. Phase I, Aim 2. Determine that intrapleural administration of LEX01 to experimental animals results in persistent, high lev- els of oxidation-resistant human AAT in serum and lung epithelial lining fluid. Phase I, Aim 3. Have a pre- IND meeting with the FDA regarding the LEX01 development plan. Phase II, Aim 1. Produce and validate GMP clinical grade LEX01 and demonstrate in experimental animals it is safe to use in a human trial. Phase II, Aim 2. Develop and validate the assays to be used in the clinical study. Submit to the FDA an IND permitting initiation of a phase I clinical study of LEX01 for AAT deficiency.

Public Health Relevance Statement:
Narrative. LEXEO Therapeutics is developing a 1st in class, next generation, gene therapy strategy to treat alpha 1-antitrypsin (AAT) deficiency, a hereditary disorder associated with early development of emphysema. The deliverable of this Fast Track application is an FDA-approved investigational new drug application permitting initiation of a phase I clinical trial to treat AAT deficiency with a single ad- ministration of LEX01, an adeno-associated gene transfer vector coding for a non-oxidizable form of AAT.

Project Terms:
Active Sites; alpha 1-Antitrypsin; alpha 1-Antitrypsin Deficiency; Animals; base; Biological Assay; Biotechnology; Cells; cigarette smoke; Clinical; Clinical Research; Clinical Trials; Code; Crystallization; Data; design; Development; Development Plans; elastase inhibitor; Elastases; Epithelial; Extracellular Matrix; FDA approved; Funding; gene therapy; Gene Transduction Agent; gene transfer vector; Generations; Goals; Hereditary Disease; Human; in vivo; Inflammatory; Infusion procedures; Investigational New Drug Application; Investments; Laboratories; Leucine; Leukocyte Elastase; Liquid substance; Liver; Lung; man; medical schools; meetings; next generation; Organ; oxidant stress; Oxidants; oxidation; Oxides; Peptide Hydrolases; Phase; Phase I Clinical Trials; Plasma; Pollution; Positioning Attribute; prevent; Problem Solving; product development; Protease Inhibitor; Proteins; Pulmonary Emphysema; Resistance; Route; Serine; Serotyping; Serum; Technology; Therapeutic; Valine; vector; Virus; Work

LEXEO Therapeutics, LLC, is an early stage biotechnology company focused on using gene therapy technologies to protect vulnerable organs from oxidant stress. LEX01, the 1st LEXEO product, is a 1st in class, next generation gene therapy treatment for alpha 1-antitrypsin (AAT) deficiency, an autosomal recessive hereditary disorder associated with low serum levels of AAT. AAT (SERPINA1), a 52 kDa serine antiprotease produced by the liver, protects the lung from proteolytic enzymes released by inflammatory cells. In AAT deficiency, the lung is vulnerable to destruction by proteolytic enzymes released by inflam- matory cells that degrade the lung, resulting in emphysema. AAT deficiency is currently treated with weekly infusions of AAT purified from pooled human plasma. Gene therapy for AAT deficiency holds the promise that a single administration will generate sufficient amounts of AAT to protect the lung on a persis- tent basis, obviating weekly AAT protein therapy. First generation gene therapy strategies are under de- velopment to treat AAT deficiency using adenoassociated virus (AAV) gene transfer vectors to deliver the human AAT coding sequence in vivo by various routes. The Achilles heel of these strategies is the sensi- tivity of the AAT molecule to oxidants. The active site of human AAT includes Met358, with a 2° contribu- tion by Met351. When oxidized (e.g., by cigarette smoke, inflammatory cell products, ambient pollution), AAT is rendered ineffective and cannot inhibit neutrophil elastase, its primary target. LEX01, designed as an AAV vector coding for an elastase-inhibiting, oxidation-resistant human AAT, solves this prob- lem with substitution at Met358 and/or Met351 with Val or Leu to render the AAT molecule oxidation re- sistant, yet maintaining its function as an anti-elastase. This is a Fast Track application with the goal of be- ing clinical trial-ready within 3 yr. Successful completion of these aims will make LEXEO attractive for biotech, pharma and/or venture investment. Phase I, Aim 1. Using the normal M1(A213) AAT coding sequence as a base, assess combinations of Met, Leu and Val at positions 351 and 358 to determine the optimal neutrophil elastase inhibiting, oxidation resistant form of AAT to use in LEX01. Phase I, Aim 2. Determine that intrapleural administration of LEX01 to experimental animals results in persistent, high lev- els of oxidation-resistant human AAT in serum and lung epithelial lining fluid. Phase I, Aim 3. Have a pre- IND meeting with the FDA regarding the LEX01 development plan. Phase II, Aim 1. Produce and validate GMP clinical grade LEX01 and demonstrate in experimental animals it is safe to use in a human trial. Phase II, Aim 2. Develop and validate the assays to be used in the clinical study. Submit to the FDA an IND permitting initiation of a phase I clinical study of LEX01 for AAT deficiency.

Public Health Relevance Statement:
Narrative. LEXEO Therapeutics is developing a 1st in class, next generation, gene therapy strategy to treat alpha 1-antitrypsin (AAT) deficiency, a hereditary disorder associated with early development of emphysema. The deliverable of this Fast Track application is an FDA-approved investigational new drug application permitting initiation of a phase I clinical trial to treat AAT deficiency with a single ad- ministration of LEX01, an adeno-associated gene transfer vector coding for a non-oxidizable form of AAT.

NIH Spending Category:
Biotechnology; Chronic Obstructive Pulmonary Disease; Emphysema; Gene Therapy; Genetics; Lung; Rare Diseases

Project Terms:
Active Sites; alpha 1-Antitrypsin; alpha 1-Antitrypsin Deficiency; Animals; base; Biological Assay; Biotechnology; Cells; cigarette smoke; Clinical; Clinical Research; Clinical Trials; Code; Crystallization; Data; design; Development; Development Plans; elastase inhibitor; Elastases; Epithelial; Extracellular Matrix; FDA approved; Funding; gene therapy; Gene Transduction Agent; gene transfer vector; Generations; Goals; Hereditary Disease; Human; in vivo; Inflammatory; Infusion procedures; Investigational New Drug Application; Investments; Laboratories; Leucine; Leukocyte Elastase; Liquid substance; Liver; Lung; man; medical schools; meetings; next generation; Organ; oxidant stress; Oxidants; oxidation; Oxides; Peptide Hydrolases; Phase; Phase I Clinical Trials; Plasma; Pollution; Positioning Attribute; prevent; Problem Solving; product development; Protease Inhibitor; Proteins; Pulmonary Emphysema; Resistance; Route; Serine; Serotyping; Serum; Technology; Therapeutic; Valine; vector; Virus; Work