Alnylam Pharmaceuticals said this week that it and collaborators have developed a novel class of lipid nanoparticles capable of greater target inhibition than the company's existing lipid delivery agents.
According to the company, the so-called reLNPs demonstrate “potent target gene silencing in vivo, with an ED50 at doses of less than 0.05 mg/kg while demonstrating tolerability at doses exceeding 10 mg/kg.”
This represents a roughly 10-fold improvement over the company's second-generation MC3 lipids, and an approximately 100-fold increase in efficacy over first-generation technologies.
The MC3 lipid is currently at issue in a lawsuit between Alnylam and partner Tekmira Pharmaceuticals (GSN 8/18/2011).
Alnylam also said that it has made improvements to its early-stage GalNAc conjugation technology for siRNA delivery
“Improvements in chemistry lead to markedly increased potency for in vivo target gene silencing with GalNAc-conjugated siRNAs administered by subcutaneous injection at low, clinically relevant doses,” Alnylam said.
Meanwhile, administration of GalNAc-conjugated siRNAs against transthyretin, the target of the firm's phase I transthyretin-mediated amyloidosis therapy ALN-TTR01, resulted in robust gene silencing in preclinical animal models with an ED50 of approximately 5 mg/kg after a single subcutaneous injection.
Earlier this year, Alnylam CEO John Maraganore called conjugate-based delivery approaches “the future for delivery of small interfering RNAs” (GSN 6/2/2011).