Developmental and Reproductive Toxicity Testing Strategies for Oligonucleotides: A Workshop Proceedings.

A 2023 workshop brought together stakeholders involved in the development and safety assessment of oligonucleotide (ONT) therapeutics. The purpose was to discuss potential strategies and opportunities for enhancing developmental and reproductive toxicity (DART) assessment of ONTs. The workshop was timely, bringing together regulators, industry representatives, consultants, and contract research organization partners interested in the ongoing development of internationally harmonized guidance for nonclinical safety assessment of ONTs. Given DART's importance in nonclinical safety assessment and the unique attributes of ONTs, the forum discussed case studies, consensus approaches, and areas needing further development to optimize DART strategies. This report covers the workshop proceedings, highlighting methods to achieve a robust DART assessment for ONTs. It includes case studies that described strategies for dose level selection, dosing frequency, species selection, and alternative animal model approaches. Topics also cover surrogate ONT use, exposure of the placenta and embryo/fetal compartment, and weight of evidence approaches. A goal of these workshop proceedings is to describe example approaches to hopefully inform the DART strategy expectations in the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidance currently under development for nonclinical safety assessment of ONTs.