This technology uses engineered human enzymes with enhanced activity to efficiently break down toxic homocysteine, offering improved treatment for metabolic disorders like homocystinuria and hyperhomocysteinemia through enzyme therapy, gene therapy, or pharmaceutical formulations.
Background
Homocystinuria and hyperhomocysteinemia are inherited or acquired metabolic disorders characterized by elevated levels of homocysteine and its oxidized form, homocystine, in the blood. These conditions are most commonly caused by deficiencies in enzymes such as cystathionine β-synthase (CBS) or disruptions in folate metabolism, leading to the accumulation of toxic sulfur-containing amino acids. Elevated homocysteine is a significant risk factor for a range of serious clinical complications, including thromboembolic events, cognitive impairment, osteoporosis, and ocular abnormalities such as lens dislocation. The management of these disorders is crucial, as untreated patients face increased morbidity and mortality due to the systemic effects of homocysteine toxicity. There is a clear need for effective therapeutic strategies that can reliably and safely lower homocysteine levels in affected individuals.
Current approaches to treating homocystinuria and hyperhomocysteinemia primarily rely on dietary restriction of methionine, supplementation with vitamins such as B6, B12, and folate, and the use of betaine to promote alternative metabolic pathways. However, these strategies often fail to achieve adequate metabolic control, particularly in patients who are unresponsive to vitamin therapy or who have severe enzyme deficiencies. Dietary management can be difficult to maintain, especially in pediatric populations, and does not always prevent long-term complications. Enzyme replacement therapies have been limited by poor catalytic efficiency, immunogenicity, and suboptimal pharmacokinetics, resulting in insufficient reduction of homocysteine levels. As a result, there remains a significant unmet need for therapies that can provide robust, sustained, and safe lowering of homocysteine to prevent the devastating consequences of these metabolic disorders.
Technology Description
This technology is an engineered human cystathionine-γ-lyase (CGL) enzyme specifically designed to efficiently degrade homocysteine and homocystine, addressing the metabolic disorders homocystinuria and hyperhomocysteinemia. The enzyme features a set of targeted amino acid substitutions (E59I, S63L, L91M, R119D, K268R, T311G, E339V, and I353S) that dramatically enhance its catalytic efficiency—achieving up to a 60-fold increase in homocysteine hydrolysis compared to the wild-type enzyme. To optimize its therapeutic potential, the modified CGL can be conjugated with polyethylene glycol (PEG) or fused to other protein domains, improving its pharmacokinetic profile and reducing immunogenicity. The technology also includes codon-optimized nucleic acids for high-yield expression in various host systems, enabling both recombinant protein production and gene therapy approaches. Pharmaceutical formulations are designed for multiple administration routes, and the solution is suitable for both acute and long-term management of elevated homocysteine levels.
What sets this technology apart is its comprehensive and highly targeted approach to homocysteine degradation. Unlike conventional treatments—such as dietary restriction or vitamin supplementation—which often fail to adequately control homocysteine levels, this engineered enzyme directly and efficiently lowers serum homocysteine, with minimal off-target activity toward other amino acids like methionine and cysteine. The versatility of the platform, encompassing PEGylation, fusion proteins, gene therapy vectors, and adaptable pharmaceutical formulations, ensures broad applicability and patient compatibility. In vivo studies demonstrate robust efficacy and safety, with significant reductions in homocysteine and improved survival in animal models. Additionally, the technology’s modular design allows for use in ex vivo and in vitro applications, and its inclusion in commercial kits further extends its utility to clinical and research settings, making it a differentiated and versatile solution for managing sulfur amino acid metabolic disorders.
Benefits
- Significantly enhanced catalytic efficiency for homocysteine and homocystine degradation (approximately 60-fold increase over wild-type enzyme)
- Targeted reduction of toxic homocysteine levels to below 25 µM, addressing homocystinuria and hyperhomocysteinemia effectively
- Minimal off-target activity toward methionine and cysteine, reducing potential metabolic side effects
- Improved pharmacokinetics and reduced immunogenicity through PEGylation and fusion protein modifications
- Versatile production via recombinant expression in multiple host systems and suitability for gene therapy applications
- Multiple administration routes available, including intravenous, subcutaneous, and continuous infusion, enabling flexible therapeutic use
- Demonstrated in vivo efficacy with improved survival and safety in animal models
- Potential for ex vivo and in vitro applications, as well as inclusion in commercial therapeutic kits
Commercial Applications
- Treatment of homocystinuria
- Treatment of hyperhomocysteinemia
- Gene therapy for metabolic disorders
- Ex vivo homocysteine depletion kits
- Recombinant enzyme pharmaceutical production
Additional Information
This technology presents engineered human cystathionine-γ-lyase enzymes with specific amino acid substitutions. These modified enzymes exhibit significantly enhanced homocystinase and homocysteinase activity, approximately 60-fold greater than wild-type, efficiently degrading homocyst(e)ine. They address homocystinuria and hyperhomocysteinemia, can be PEGylated for improved pharmacokinetics, and are deliverable via nucleic acids for recombinant production or gene therapy.
Patent 12,036,269
