May is the time of year when the American Society for Gene and Cell Therapy (ASGCT) has its annual meeting. This is traditionally when researchers in the field publish papers and deliver abstracts which represent the cutting-edge of gene therapy science.
In the past, many abstracts have been presented on ddRNAi and its application as a mode of treatment for various diseases. This year there are also a number of abstracts that can now be viewed online at http://www.abstracts2view.com/asgct/
There are two many to summary here and so I encourage anyone interested in the science to visit this site and browse the material there.
Some abstracts that are noteworthy are from Calimmune, City of Hope (CoH) and Gradalis; Calimmume and the City of Hope because of their partnerships with Benitec (OTCPK:BNIKF) and Gradalis because the first Phase I clinical trial results are discussed.
The new research from Calimmune showcases their continued refinement of their approach to treating HIV. The paper concludes:
These results demonstrate the potential for gene-containing lentiviral vectors to treat HIV infection; there is both stability of the insert and absence of negative effects. These results indicate that both of the examined therapeutic genes protect against HIV infection. They show, more importantly, that the combination of these genes in a single construct provides greater protection than either therapeutic alone, indicating an additive effect of the genes. This finding shows great promise for the use of combination gene therapies in the treatment of HIV infection.
While this was only an in vitro study, the research demonstrated on-going prevalence of the modified cells in the culture. If this is able to be repeated in patients, then not only a cure but also long term immunity from HIV could be possible for those treated.
The papers from the CoH also point to a tipping point in the fight against HIV. The CoH research shows that using ddRNAi to target the viral RNA is just as effective on its own as the combination of this plus inhibiting HIV entry (the Calimmune approach). The clinical trial of this research is currently recruiting. (It may be worth noting that, in the case of HCV, Benitec's TT-034 is designed to use the technique of targeting the viral RNA.)
CoH also presented another abstract. This paper shows how the CoH is working on refinements to ddRNAi to improve efficiency and remove toxicity.
Gradalis presented a number of papers. While this company is yet to licence ddRNAi from Benitec, its results are nevertheless noteworthy. (I would add that Gradalis have enhanced and extended ddRNAi so their results, while relating to ddRNAi, are, arguably, not purely due to ddRNAi.)
One of the papers discusses the results of their Pl trial for Advanced Cancer. The abstract states:
STMN1 is a microtubule destabilizing protein critical in the control of mitosis and is differentially overexpressed in malignant versus non-malignant tissue. Using our novel RNA interference construct, pbi-shRNA™-STMN1 nanoplex, we previously demonstrated STMN1 expression knockdown in surgically obtained human tumors as well as safety and efficacy in animal xenograft and tumor graft models thereby justifying Phase I testing (BB-IND 14938).
Eleven patients (angiosarcoma, anal, colorectal, sarcoma, head and neck, ovarian, melanoma x2 and breast cancer x3) have entered into our dose-escalation trial. Design is shown in Figure 1. PK analyses of circulating plasmid of evaluable patients in cohorts 1 and 2 is shown in Figure 2. No toxic effects were observed. All patients demonstrated stable disease during the first month post-treatment. Intratumoral cleavage product was demonstrated in cohorts 1 and 2 by next generation sequencing and by RLM RACE assay in cohort 3.
These results support continuation of Phase I testing and establish the basis for transition to systemic treatment starting at a dose level equivalent to demonstrated safe plasmid levels in circulation.
This means the company sees this research as being able to be transitioned into a commercial proposition (assuming all approvals are given). Clearly, more work will be required to get there, but the Pl results demonstrate that ddRNAi is a viable mode of treatment for Advanced Cancer.
Several other indications are reported on by various research organizations. What this demonstrates is the vitality in ddRNAi research and the breadth of coverage outside of Benitec's own pipeline. These papers should give confidence to any investor that the technology is sound and very close to being commercially viable.
Disclosure: I am long BNIKF.
Additional disclosure: This article is not intended as investment advice. Reader should do their own research.