Monday, April 28, 2025
4/28/2025
NEW REAGENTS FOR SYNTHESIZING NUCLEASE-RESISTANT SIRNA - DESCRIPTION (provided by applicant): The siRNA molecule needs better protection from nuclease degradation before it can be effectively used as a therapeutic. AM Biotechnologies (AM) will address this critical issue by developing ribonucleoside thiophosphoramidite (ABz, CBz, GIbu and U) reagents that will enable synthesis of phosphorodithioate siRNA (PS2-siRNA). This synthesized PS2-siRNA will significantly increase siRNA nuclease resistance; lower Tm, which could help the activated RISC unwind siRNA; and enhance the pharmacokinetic properties of siRNA. The PS2-siRNA will also be achiral at phosphorus, which will eliminate the variable biochemical, biophysical, and biological properties of diastereomeric phosphoromonothioate substituted siRNAs (PS-siRNAs). In this Phase I SBIR project, AM will: 1) develop the chemistry and optimize the conditions to produce four ribonucleoside thiophosphoramidites (ABz, CBz, GIbu and U); 2) demonstrate high coupling yield (>97%) in the synthesis of PS2-siRNAs; and 3) evaluate PS2-siRNA gene silencing effect in vitro. In Phase II, AM will perform the research required to (a) scale reagent production up to commercial quantities and purity; (b) optimize a robust protocol for synthesis of PS2-siRNA; (c) systematically evaluate the positional effect of PS2 modification on siRNA activity in mammalian cells; (d) examine the bio-distribution of PS2-siRNA; and (e) fully characterize the pharmacokinetic properties of PS2-siRNA. AM in Phase II may also offer for sale limited quantities of research-grade reagents for market beta testing. Upon successful completion of Phase II, AM will work with its industry partners to commercialize the ribonucleoside thiophosphoramidites (R-thioamidites) and enable the entire life science community to benefit from the use of these unique reagents.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).