Sunday, June 8, 2008
RNAi Therapeutics: A Spoilt Market, or Waiting for Clinical Progress?
Actually, these platform licensing agreements are evidence for just that as the therapeutic areas covered by the non-exclusive license, namely metabolic disease and cancer, clearly indicate that the deal was driven by the maturation of liposomal RNAi delivery technology. Moreover, an important component of the Alnylam-Takeda relationship will be the exchange of RNAi delivery capabilities, suggesting that Takeda had also made progress in this area.
However, the bears would argue that what Alnylam, and the wider field, needs is further demonstrating progress with their development programs. Of course, we had the phase II ALN-RSV01 proof-of-concept data which was a great relief for everybody and should strengthen Alnylam’s position at the deal table if not on a PPS basis, but we should also remember that Alnylam had previously guided that it would advance one or two SNALP-related programs into the clinic in 2007. This has not happened and I can understand that some may have well been disappointed by that. Paradoxically, rather than reflecting science that has stalled, the delay can be explained at least partly by ongoing progress in SNALP RNAi delivery and it may not be wise to commit to a development candidate when improvements in both safety and efficacy can be made so readily as supported by recent conference presentations and publications.
Having followed biotechs for a while now, one major question I ask myself before investing in a biotech company is whether programs have been rushed into the clinic well before they have been properly validated pre-clinically. That often happens with small biotechs with acute fund-raising needs or when existing investors would like to exit and an IND is the goal, not final approval by the FDA. How otherwise could one explain e.g. Nucleonics’ decision to advance a plasmid-based, DNA-directed shRNA program for Hepatitis B into phase I when all the in vivo data consisted of some co-transfection studies (= glorified in vitro data) and when current non-viral plasmid delivery methods are unlikely to achieve the transfection rates sufficient for curing such a viral infection through direct gene knockdown. Next to Nucleonics, other early RNAi pipeline candidates, while somewhat more promising scientifically, may also serve the role of flag-waving programs demonstrating to investors that RNAi is not just a fascinating science, but also of clinical relevance.
Much has been learnt since the first candidates entered the clinic in 2004 and, like for SNALP RNAi in particular, it makes a lot of sense, also economically, to take advantage of the steep learning curve in general to increase the odds of late-stage pipeline success at the cost of slight early delays. Meanwhile, the irresistible expansion of RNAi into in vivo applications and the increasing number of RNAi-related conferences (another one, Beyond Genome, is just about to take place a little bit North of where I live) demonstrate that the field is vibrant and the science is making rapid progress.
If that weren’t enough, the coming months should bring more than enough RNAi clinical results to contemplate. Calando just reported this past week initial results from their phase I studies on CALAA-01, an unmodified siRNA in a targeted nanoparticle formulation for the treatment of solid tumours. According to their press release, the first patient has now completed a course of 4 intravenous doses over two weeks without any show-stopping adverse events. As this is the first clinical experience of systemically administered siRNAs, unmodified at that, it therefore also marks an important and reassuring milestone for the synthetic siRNA field in general. It is easy to envision scenarios how an adverse event could have had disastrous repercussions for RNAi Therapeutics. Well done, Calando!
Then there are the SNALP RNAi programs that, once entered, could yield relatively soon clear in vivo efficacy data on systemically administered RNAi Therapeutics. Finally, Benitec’s HIV program is another program that deserves some attention as quantitative patient data may emerge relatively soon; for example, an expansion of T-cells derived from the stem cells transduced with the lentiviral vector encoding for a triple-RNA antiviral relative to unmodified cells would be very promising.
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