Enhanced splicing modulation by NMA-modified antisense oligonucleotides

Ling, K.; Prakash, T. P.; Yu, J.; Jackson, M.; Chun, S. J.; Bachmann, G.; Post, N.; Greenlee, S.; Soriano, A.; Hunyara, J. L.; Norris, D. A.; Jafar-nejad, P.; Swayze, E. E.; Bennett, C. F.; Rigo, F.

doi:10.1101/2025.10.06.680653

bioRxiv · 10.1101/2025.10.06.680653

Enhanced splicing modulation by NMA-modified antisense oligonucleotides

Ling, K.·Prakash, T. P.·Yu, J.·Jackson, M.·Chun, S. J.·Bachmann, G.·Post, N.·Greenlee, S.·Soriano, A.·Hunyara, J. L.·Norris, D. A.·Jafar-nejad, P.·Swayze, E. E.·Bennett, C. F.·Rigo, F.

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Abstract

Aberrant RNA splicing contributes to many human diseases, and splice-switching antisense oligonucleotides (SSOs) are ideally suited as a therapeutic strategy to modulate splicing and restore normal gene expression. Nusinersen (Spinraza) has revolutionized the treatment of spinal muscular atrophy. It is a splice-switching oligonucleotide (SSO) that is modified with 2-O-methoxyethyl (MOE) modifications. Here, we introduce a next-generation ribose modification, 2'-O-[2-(methyl-amino)-2-oxoethyl] (NMA), which enhances the pharmacological properties of SSOs. We identified a long-lasting NMA-modified human candidate SSO, salanersen, that is 3-4-fold more potent than nusinersen in human SMN2 transgenic mice. To evaluate the generality of the NMA chemistry, we applied it to modulation of SCN1A exon 20N splicing, a therapeutic strategy for Dravet syndrome. An NMA-modified SSO is 3.5-fold more potent than STK-001, a MOE-modified SSO currently in clinical trials. Our data establish the NMA chemistry as a broadly applicable ribose modification that markedly improves the pharmacological profile of SSOs, supporting its development as a next-generation platform for splicing modulation therapies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=69 SRC="FIGDIR/small/680653v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@122e426org.highwire.dtl.DTLVardef@1b0a56eorg.highwire.dtl.DTLVardef@3ce4e8org.highwire.dtl.DTLVardef@1d86378_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Ling, K., Prakash, T. P., Yu, J., Jackson, M., Chun, S. J., Bachmann, G., Post, N., Greenlee, S., Soriano, A., Hunyara, J. L., Norris, D. A., Jafar-nejad, P., Swayze, E. E., Bennett, C. F., Rigo, F.. 2025-10-07. Enhanced splicing modulation by NMA-modified antisense oligonucleotides. https://doi.org/10.1101/2025.10.06.680653

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