Enabling Gene Therapy: UBC Research Leads to First Successful Phase 3 Trial for an RNAi Gene Therapy Drug

Alnylam Pharmaceuticals (Boston, USA) and Sanofi (Gentilly, France) announced Tuesday, September 20 the first positive Phase 3 results for an RNA interference (RNAi) drug (Patisiran) which met its primary efficacy endpoint and all secondary endpoints (see http://investors.alnylam.com/releasedetail.cfm?ReleaseID=1041081). Patisiran, which treats a hereditary disease called amyloidogenic transthyretin (ATTR) amyloidosis, is likely to become the first systemic non-viral gene therapy drug to be approved by the US FDA and marks the arrival of an entirely new class of gene therapy medicines.

Patisiran is enabled by a lipid nanoparticle (LNP) delivery technology developed in the laboratory of Professor Pieter Cullis (UBC Biochemistry, UBC Life Sciences Institute) in collaboration with Alnylam and two UBC spin-off companies he co-founded: Arbutus Biopharma and Acuitas Therapeutics. Professor Marco Ciufolini of the UBC Chemistry Department also played an important role in developing more potent LNP systems. The LNP technology appears to have general applicability for enabling gene therapies, Acuitas and collaborators have shown that related LNP systems show considerable potential for enabling mRNA to be used as vaccines(1) and to produce therapeutic proteins(2).

Patisiran consists of LNPs containing short interfering RNA (siRNA) that, if delivered to the interior of a target cell, will “silence” a gene coding for a protein called transthyretin (TTR), a transport protein found in the circulation. Mutations in the TTR gene can cause the TTR protein to aggregate into amyloid plaques that deposit in nerve and cardiac tissue, causing nerve and heart damage. The disease is currently incurable. Among other benefits, the Phase 3 trial showed that treatment with Patisiran improved the neuropathy impairment score in patients, meaning that nerve function stabilized or improved, and the self-reported quality of life improved as compared to treatment with placebo.

Professor Cullis comments that “these results validate work conducted since 1995 to develop LNP delivery systems that facilitate intracellular delivery of RNA and DNA polymers. An incredible team was assembled at Acuitas, Alnylam, Arbutus, and UBC to develop the LNP siRNA nanomedicine now known as Patisiran. Advances made were built on experience gained developing LNP delivery systems in my laboratory at UBC since I established it in 1978, so in many ways the success of Patisiran is the highpoint of my career. I need to acknowledge the efforts of literally hundreds of people who have contributed to the development of this drug, as well as to CIHR and its precursor MRC, who have provided continuous funding to my laboratory for the past 39 years.”

1) Pardi et al., Zika virus protection by a single low dose nucleoside-modified mRNA vaccination, Nature 248, 543 (2017)
2) Pardi et al., Administration of nucleoside-modified mRNA encoding broadly neutralizing antibody protects humanized mice from HIV-1 challenge; Nature Communications DOI: 10.1038/ncomms14630 (2017)