Considerations in the Preclinical Assessment of the Safety of Antisense Oligonucleotides

Abstract

The nucleic acid therapeutics field has made tremendous progress in the past decades. Continuous advances in chemistry and design have led to many successful clinical applications, eliciting even more interest from researchers including both academic groups and drug development companies. Many preclinical studies in the field focus on improving the delivery of antisense oligonucleotide drugs (ONDs) and/or assessing their efficacy in target tissues, often neglecting the evaluation of toxicity, at least in early phases of development. A series of consensus recommendations regarding regulatory considerations and expectations have been generated by the Oligonucleotide Safety Working Group and the Japanese Research Working Group for the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use S6 and Related Issues (WGS6) in several white papers. However, safety aspects should also be kept in sight in earlier phases while screening and designing OND to avoid subsequent failure in the development phase. Experts and members of the network “DARTER,” a COST Action funded by the Cooperation in Science and Technology of the EU, have utilized their collective experience working with OND, as well as their insights into OND-mediated toxicities, to generate a series of consensus recommendations to assess OND toxicity in early stages of preclinical research. In the past few years, several publications have described predictive assays, which can be used to assess OND-mediated toxicity in vitro or ex vivo to filter out potential toxic candidates before moving to in vivo phases of preclinical development, that is, animal toxicity studies. These assays also have the potential to provide translational insight since they allow a safety evaluation in human in vitro systems. Yet, small preliminary in vivo studies should also be considered to complement this early assessment. In this study, we summarize the state of the art and provide guidelines and recommendations on the different tests available for these early stage preclinical assessments.

Investigating the Impact of Delivery Routes for Exon Skipping Therapies in the CNS of DMD Mouse Models

“…Besides the lack of improvement in exon-skipping efficacy, the administration of a high dose of tcDNA was not very well tolerated by the mice, which showed general reduced mobility and weight loss with hypoactivity and a lack of responsiveness. Such toxicities have previously been observed following the direct injection of charged ASO in the CNS of rodents [ 34 , 35 , 36 ] and highlight the need to perform detailed safety studies before considering the potential future application to DMD patients [ 37 ]. Furthermore, we detected particularly high variability with this procedure, thus questioning its reproducibility.…”

A Precision Therapy Approach for Retinitis Pigmentosa 11 Using Splice-Switching Antisense Oligonucleotides to Restore the Open Reading Frame of PRPF31

“…These effects are influenced by the chemical modifications to the nucleobases and backbone; however, careful design and the highly specific base pairing with target mRNA can limit off-target hybridization. A comprehensive review of pre-clinical assessments of AOs has been thoroughly conducted by Goyenvalle et al [ 55 ].…”

Deep learning facilitates efficient optimization of antisense oligonucleotide drugs

“… 3 To ensure the safety and efficacy of ASO drugs, researchers have been working on reducing “off-target effects” and chemically modifying nucleotides to minimize side effects. 5 …”