Progress in The Development Of Nucleic Acid Drugs And Prisys Biotech’s Research Capabilities

In modern medicine, nucleic acid drugs are emerging as powerful tools for treating various diseases. Unlike traditional small molecule and antibody drugs, nucleic acid therapeutics directly target genetic material-RNA or DNA-providing a novel approach to addressing previously "undruggable" targets. This article outlines the development progress of nucleic acid drugs and highlights Prisys Biotech's capabilities in this cutting-edge field.

Nucleic acid drugs have made significant strides in recent years, particularly in treating cardiovascular, metabolic, liver diseases, and various rare disorders. These drugs function by modulating target protein RNA, RNA editing, or expressing functional proteins through nucleic acid vectors (DNA) or mRNA, offering a fresh therapeutic approach.

Types of Novel Nucleic Acid Therapeutics

Nucleic acid drugs primarily include small interfering RNA (siRNA), antisense oligonucleotides (ASOs), adeno-associated virus (AAV) vectors, and mRNA. These molecules utilize different mechanisms to achieve therapeutic outcomes, such as RNA downregulation, RNA editing, or mRNA expression, providing diverse treatment options.

Preclinical Pharmacological Challenges

Despite their therapeutic potential, nucleic acid drugs face two primary challenges in preclinical pharmacology: delivery and safety. Given their distinct mechanisms compared to traditional drugs, innovative approaches are required to overcome these obstacles.

Drug Delivery Challenges

• Targeted Delivery: Nucleic acid drugs must be precisely delivered to specific cells or tissues to ensure efficacy and minimize off-target effects. However, due to their large, negatively charged structures, these molecules have difficulty crossing cell membranes, and their distribution in vivo can be uneven.
• Avoiding Rapid Clearance: Stability in vivo is a major concern, as nucleic acid drugs can be quickly degraded by nucleases, leading to reduced drug concentration and efficacy.
• Systemic Delivery: The distribution of nucleic acid drugs in the body is influenced by factors such as circulation, cellular uptake, and tissue penetration. Achieving effective systemic delivery, particularly in large animal models, requires specialized delivery systems like liposomes, nanoparticles, or viral vectors.
• Crossing Biological Barriers: Organs such as the brain and eyes are protected by biological barriers like the blood-brain barrier and blood-retinal barrier, which restrict drug delivery. Developing systems capable of overcoming these barriers is key for treating diseases in these organs.

Safety Assessment Challenges

• Immunogenicity and Immunotoxicity: Nucleic acid drugs can trigger immune responses, leading to inflammation or other adverse effects. Assessing immunogenicity and strategies such as chemical modification or the use of immunosuppressants to mitigate immune reactions are crucial aspects of preclinical studies.
• Off-Target Effects: Due to the sequence-specific binding mechanisms of nucleic acid drugs, there is a potential for off-target binding, resulting in unintended biological effects.
• Dose-Dependent Toxicity: The toxicity of nucleic acid drugs may be dose-related, with high doses possibly causing cytotoxicity or tissue damage. Determining a safe and effective dosage range is a critical focus of preclinical studies.
• Long-Term Stability and Cumulative Toxicity: Long-term stability and cumulative effects of nucleic acid drugs in the body need careful evaluation to ensure safety over extended use.
• Vector Safety: For nucleic acid drugs using viral vectors like AAV, assessing the safety of the vector itself, including potential risks of insertional mutagenesis and host immune responses to the vector, is essential.

Preclinical Research Strategies

To overcome these challenges, researchers employ various strategies:

• Chemical Modifications: Modifying nucleic acid molecules, such as adding protective groups or using modified nucleotides, can enhance stability and reduce immunogenicity.
• Optimizing Delivery Systems: Developing advanced delivery systems, such as lipid nanoparticles or solid lipid nanoparticles, can improve the efficiency and specificity of nucleic acid drug delivery.
• Immune Modulation: Using immunosuppressants or designing immune-silent nucleic acid drugs can help reduce immune reactions.
• Pharmacokinetic and Toxicology Studies: Conducting detailed pharmacokinetic and toxicology studies is essential to evaluate the distribution, metabolism, excretion, and toxicity of nucleic acid drugs in vivo.
• Animal Model Studies: Extensive pharmacodynamic and safety evaluations in animal models are conducted to predict potential clinical outcomes and risks.

Prisys Biotech's in vivo pharmacology team has developed the expertise to study the pharmacodynamics and pharmacokinetics of novel nucleic acid molecules in central nervous system (CNS), liver, eye, ear, and other organs using non-human primate (NHP) models. This includes localized delivery, in vivo sampling, and imaging studies. Prisys Biotech has also established a comprehensive platform for innate and adaptive immune response research, enabling preclinical evaluations of the immunogenicity and immune responses of oligonucleotides and AAV in large animals.

Case Studies

Prisys Biotech demonstrates how animal models can address pharmacological challenges of nucleic acid therapeutics through several case studies:

• Case 1: Intracerebroventricular (ICV) vs. Intrathecal (IT) Injection Researchers compared two delivery methods: ICV and IT injection of oligonucleotides. ICV injection showed significant downregulation of target RNA in the striatum, prefrontal cortex, and cervical spinal cord, but had weaker effects on dorsal root ganglia. Conversely, IT injection achieved higher downregulation in dorsal root ganglia and lumbar spinal cord, but lower effects in the striatum and prefrontal cortex. This comparison highlights the impact of different delivery routes on CNS drug distribution and efficacy.
• Case 2: Targeted AAV Delivery and Safety in NHP Brains Prisys Biotech tested AAV antibodies in cynomolgus monkeys and selected antibody-negative animals for lumbar IT injections. Some animals exhibited fever and seizures post-administration, but symptoms resolved within 24 hours. In subsequent experiments, pre-administration of immunosuppressants successfully prevented these acute reactions, providing insights into managing immune responses during AAV therapies.
• Case 3: Oligonucleotide Efficacy in Animal Models In a long-term study, oligonucleotide efficacy was tested in a transgenic animal model with disease-related gene mutations. After two doses, researchers monitored survival, body weight, clinical scores, and motor function. Animals treated with oligonucleotides showed no mortality, sustained weight gain, and minimal symptoms, while control animals exhibited significant weight loss, neurological symptoms, and over 50% mortality by the end of the study. These results confirm the therapeutic efficacy of oligonucleotides in this model.

Prisys Biotech's Preclinical In Vivo Pharmacology Platform

Prisys Biotech's in vivo pharmacology platform is supported by a highly skilled management and technical team with extensive experience in relevant disease areas. The platform is equipped to provide comprehensive pharmacology and efficacy testing services across all major disease fields, supporting various animal models and drug efficacy tests.

The development of nucleic acid drugs is both a challenging and promising field. With its robust research platform and expert team, Prisys Biotech is becoming a leader in this space. We look forward to Prisys Biotech's continued innovation in therapeutic development, offering new hope to patients worldwide.