Mar 6 2009
Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, today announced the publication of new data in the journal Molecular Therapy by Alnylam scientists and collaborators from the David H. Koch Institute for Integrative Cancer Research at the Massachusetts Institute of Technology (MIT). These new data describe the further development of lipidoid formulations for the systemic delivery of small interfering RNAs (siRNAs), the molecules that mediate RNAi.
"We are very encouraged with the progress we have made with systemic delivery of siRNAs since the continued advancements we and our collaborators are making with this technology is enabling the ability to address the broadest potential of RNAi therapeutics," said Akin Akinc, Ph.D., Associate Director, Research at Alnylam. "Formulations based on lipid and lipid-like materials called ‘lipidoids' show great promise for the systemic delivery of RNAi therapeutics. These new findings further expand our understanding of lipidoids as part of our ongoing efforts to optimize these formulations to maximize efficacy in vivo."
Lipidoids are a new class of lipid-based molecules which are used to form novel nanoparticle formulations for systemic delivery of RNAi therapeutics. A previous study by Alnylam scientists in collaboration with scientists from MIT (Akinc et al., Nature Biotechnology 26, 561-569 (01 May 2008)), showed successful delivery of siRNAs encapsulated in lipidoid formulations when administered in multiple animal species including mice, rats, and non-human primates.
Data published from this new study (Akinc et al., Molecular Therapy advance online publication 3 March 2009; doi:10.1038/mt.2009.36) extends the work from the previous study by:
- identifying key parameters affecting the pharmacodynamics of this type of formulation, including increasing the anchor length of synthesized PEG lipids, maximizing siRNA loading, and reducing particle size to more efficiently access hepatocytes;
- demonstrating that lipidoid formulations achieve delivery of greater than 90% of the administered siRNA dose to the liver and maintain robust in vivo activity following repeat administration over a period of several months, and indicating no evidence of neutralizing antigenicity or tachyphylaxis; and,
- characterizing the long-term stability of the formulation.
Lipidoid formulations represent one of several approaches Alnylam is pursuing for systemic delivery of RNAi therapeutics. Additional approaches include other lipid nanoparticle formulations and siRNA conjugation strategies. Recently, Alnylam received clearance from the U.S. Food and Drug Administration (FDA) for its investigational new drug (IND) application to initiate a Phase I study for its ALN-VSP liver cancer program, which it expects to begin enrolling in the first half of 2009. ALN-VSP employs a lipid nanoparticle formulation known as "SNALP" developed in collaboration with Tekmira Pharmaceuticals Corporation.