Thursday, August 14, 2008
Bristol-Myers Squibb Deal Further Positions Tekmira as RNAi Therapeutics Delivery Hub
SNALP RNAi delivery is well validated for gene knockdown in the liver, including in non-human primates. Just this week, Alnylam published in the scientific journal PNAS the lowering of PCSK9, a cardiovascular disease target, in rodent and monkey liver using SNALP liposomes. For clarification purposes since there has been much confusion on the issue of SNALPs and lipidoids, while the particular SNALP formulation used in the publication contained lipidoids, lipidoids are just one of the various other lipids that could be used with SNALP technology. Moreover, Tekmira has non-exclusive access to lipidoids from the MIT via Alnylam in case they wanted to incorporate them into their own SNALPs.
Investing in SNALP delivery outside the liver (Tekmira expects to receive $450k from BMS for the second half of 2008) should therefore expand the therapeutic potential of this technology and directly aid the development of a broad and balanced Tekmira RNAi Therapeutics pipeline. Strategically, it should also provide Tekmira with a potential future development partner and access to disease know-how and gene targets.
Cancer is the most obvious non-liver target given what we know from the passive targeting of SNALP/liposomal particles to solid cancer tissues. Further validation for the concept of using liposomal RNAi delivery for cancer comes from plasmid delivery data from Tekmira itself and various liposomal RNAi publications by others. Some of that research made use of active tumor targeting, and it is not far-fetched that the research collaboration will also consider such active targeting strategies. These may also hold promise for indications outside solid cancer such as hematological malignancies, blood vessel-related disorders (e.g. cardiovascular/metabolic disorders), and immunological diseases.
Cancer and metabolic/cardiovascular disease would also make sense as the two focus areas of BMS research and development. While the scope of the Tekmira-BMS collaboration may indicate that the returns of investing in SNALP delivery to the liver are diminishing with first INDs expected to be filed within the next 12 months, it may also be interpreted as accommodating Alnylam or even point towards a follow-on deal with Alnylam which may not want to further dilute the perceived value of what it has granted its previous platform licensing partners.
Cancer on the other hand is a genetically highly diverse set of diseases, and with SNALP and RNAi, Big Pharma must feel like kids in a candy store with more than enough targets and unmet needs for everybody to pick from. One note of caution though is that while SNALP RNAi has demonstrated potent activity in pre-clinical models of liver cancer, much less is known about its actual knockdown activity in other cancer types. It will therefore be important to confirm the clinical feasibility of SNALP RNAi for cancer through conference presentations and scientific publications.
BMS’ decision, of course, has also to be seen as part of the rush by Big Pharma to transform themselves into developers of innovative biotech drugs. Offers by Roche and BMS itself for Genentech and Imclone, respectively, are just two recent high-profile examples. The deal also demonstrates BMS’ increasing commitment towards the RNAi platform. Only last year, BMS entered into an antisense collaboration with ISIS Pharmaceuticals for PCSK9 knockdown in cardiovascular disease. Interestingly, this was largely based on BMS’ successful validation of PCSK9 as a cardiovascular target using RNAi (and as we now know most likely SNALP-enabled as part of the BMS-Protiva target validation collaboration), data of which was presented at last year’s OTS meeting in Berlin. When asked why BMS decided on antisense, not RNAi in light of the impressive RNAi data presented, the response was that ISIS’ mipomersen represented clinical proof-of-concept that antisense could knock down genes in human liver. It now seems that like other pharmaceutical companies, positive experience with RNAi as a target validation tool has translated into embracing it as a therapeutic platform in its own right.
The one-million-dollar question weighing on the minds of Alnylam investors will be whether yesterday’s development heralds the next Alnylam platform alliance deal. In the past, partners tended to come to Tekmira as Alnylam sub-licensees. Although details of the deal are lacking, due to otherwise too many potential conflicts-of-interests and the importance of Alnylam to Tekmira, it is unlikely that BMS will turn out to be a Merck-like star in the Alnylam-Tekmira constellation. Given that Tekmira has inherited a number of additional technology feasibility partnerships with Big Pharma and biotech from Protiva, further such deals are likely to materialize with Tekmira functioning as one of Alnylam's baits.
An interesting aspect in this context is that the corresponding author of this week’s paper, Kevin Fitzgerald, came to Alnylam (leader of the oncology and cardiovascular/metabolic disease group) from BMS. At BMS, he had been part of the target validation group, very likely the same group that had been involved in the BMS-Protiva collaboration. Obviously, RNAi has not disappointed him, but beyond that, is this part of a larger puzzle?
Now that Tekmira has RNAi delivery partnerships with Alnylam, Roche, Merck, Takeda, and BMS, and more to come, the 100-employee strong Tekmira is slowly emerging as the RNAi Therapeutics delivery hub. This also starts to pay off financially with essentially no appreciable decrease in cash reserves over the last quarter. It will also be interesting whether Tekmira will pursue interests beyond liposomal RNAi delivery. Combining various delivery technologies into one operation, whether as an independent company or not, would have a number of synergies as many of the same questions need to be addressed with the different technologies.
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