Table 3.

Safety concerns with RNA therapies and possible approaches to address them

Safety concern category	Safety concern	Possible approaches to address the concern
Challenges in toxicological assessments	Lack of consensus in design of toxicity study packages	Designing regulatory guidelines specifically for siRNA
	Lack of correlation between pre-clinical and clinical toxicological studies	Designing more predictive pre-clinical studies by addressing translational gaps
	Toxicity observed in diseased people	Mechanistic understanding of the effect of disease setting and concomitant medications on immunogenicity and toxicity profile of the siRNA therapies
	Failure of siRNA therapies due to safety concerns at late stages	Implementing HTS of siRNA therapies using: Organ on chip technology for toxicity screening NP barcoding for better targeting In silico toxicity screening
siRNA intrinsic toxicity	Immunogenicity of siRNA	Chemical modification of siRNA such as incorporation of 2’- OMe,2′-F, or 2'-H Decrease PS content
	Hybridization-dependent off-target toxicities	In-silico assisted seed region design with minimal complementarity to 3'UTRs Chemical modification of siRNA
	Hybridization-dependent on-target toxicities	Effective targeting
	Saturation of RNAi machinery	Dose adjustment of siRNA
Delivery-mediated toxicity	Immunogenicity of the carrier	Surface modification Incorporation of cleavable PEGs Premedication, co administration, or co-encapsulation of glucocorticoids or JAK inhibitors
	Chemistry-related toxicities of carrier	Shielding the positive surface charge of the polymer-based carriers Surface modification Use of ionizable lipids instead cationic lipids Use of more potent carriers to avoid DLTs Use of biodegradable carriers Use of steropure ionizable lipids Effective targeting Enhanced endosomal escape Monitoring endosomal accumulation of GalNAc- siRNA Dose fractionation to avoid receptor saturation for GalNAc-siRNA