Ocular biodistribution and duration of action of low-dose LNA oligonucleotides

Abstract

Purpose : To assess the biodistribution and the duration of action of an IVT administered LNA oligonucleotide at low dose levels.

Methods : Locked-nucleic acids (LNAs) are modified RNA nucleotides in which a methylene bridge has been introduced between the 2’ O and 4’ C. This modification greatly improves binding affinity, as well as increasing nuclease resistance and target specificity. LNAs can be combined with DNA nucleotides to form single strand oligonucleotides of various designs. A common variety is a gapmer, which consists of a DNA central part (7-12 nucleotides) flanked by short LNA segments (2-4 nucleotides) at each end. When gapmers bind to mRNA, the heteroduplex recruits RNAse H which then cleaves the mRNA.
RO7111921 is a 16 nucleotide gapmer with 3-10-3 LNA-DNA-LNA design. The compound targets human VEGFA and has full sequence homology in cynomolgus monkeys, mouse, pigs, rabbits and rats.
The biodistribution and target engagement of RO7111921 was assessed after single-dose intravitreal (IVT) injection in animal models. Ocular compound distribution was assessed by hybridization ELISA. Target engagement was assessed on mRNA level by quantitative Polymerase chain reaction (qPCR) and by ELISA on protein level.

Results : Intravitreal injection of RO7111921 in minipig eyes resulted in distribution to all layers of the neural retina as well as the retinal pigment epithelium (RPE). A low-dose of 25 µg maintained a significant knock-down of VEGFA mRNA in retina and choroid-RPE complex up to 90 days post-dose. A potent reduction of at least 85% VEGF protein in vitreous humor was observed throughout the study period of 120 days.

Conclusions : LNA oligonucleotides distribute broadly to ocular tissues after intravitreal injections and result in long-lasting target knock-down.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

Pharmakokinetics after low-dose RO7111921 in minipigs (25 µg/eye, SD IVT). Tissue concentration of RO7111921 in retina and choroid (ng/g tissue, log₁₀ scale)

 

Duration of action after low-dose RO7111921 in minipigs (25 µg/eye, SD IVT).
Top: Residual VEGFA mRNA in retina and choroid, normalised to PBS control. Bottom: Residual VEGFA protein in vitreous, normalised to PBS control.