This USFDA draft guidance"Nonclinical Safety Assessment of Oligonucleotide-Based Therapeutics", issued on 15 November 2024, offers comprehensive recommendations for the nonclinical safety evaluation of oligonucleotide-based therapeutics (ONTs). These guidelines aim to assist in clinical development and marketing authorization while addressing ONTs' unique characteristics compared to traditional small-molecule drugs and therapeutic proteins.
Oligonucleotide-based therapeutics are a class of drugs designed to modulate gene expression or protein function by interacting with specific sequences of DNA or RNA. The guidance provides a framework for evaluating their safety profiles, considering unique pharmacological and toxicological aspects.
FDA is publishing this draft guidance which, when finalized, will provide recommendations on approaches for the nonclinical safety evaluation of oligonucleotide-based therapeutics (ONTs) to support clinical development and marketing of these products.
Nonclinical safety evaluations of ONTs present unique challenges. Even though existing guidance for small molecule drugs and therapeutic proteins mentions ONTs, this guidance provides detailed recommendations for nonclinical assessment of ONTs that have been developed based on experience so far. These recommendations address ONT characteristics that differ from small molecule drugs and therapeutic proteins. The guidance applies to:
Single-stranded or double-stranded ONTs with natural or modified structures.
ONTs intended for increased or decreased protein expression/function, such as antisense oligonucleotides, siRNAs, and aptamers.
ONTs typically act by:
Binding to complementary nucleic acid sequences (hybridization).
Modulating gene expression through antisense or silencing mechanisms.
Binding to proteins or cellular components (e.g., aptamers).
Safety Assessments involve the
On-Target Effects: The assessment focuses on exaggerated pharmacological effects.
Off-Target Hybridization-Dependent Effects: Investigates unintended binding to non-target sequences using in silico and in vitro methodologies.
Off-Target Hybridization-Independent Effects: Empirical toxicity studies are crucial for understanding interactions with non-nucleic acid targets.
ONTs should be evaluated for their mode of action and/or effects according to their intended therapeutic targets in primary pharmacology studies. Moreover, these studies can provide information about their duration and can be used to select the appropriate dose for both clinical and nonclinical studies. Safety pharmacology evaluations of ONTs should address the effects of the drug substance on vital functions.
ONTs should be analyzed for nonclinical absorption, distribution, metabolism, and excretion parameters to inform safety assessments to support clinical trials. For detailed information, refer to the full guidance document:
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