The Tide May Have Turned for ARWR

Arrowhead Research emerged as a major RNAi Therapeutics player due to its- at least publicly- single-minded focus on HBV.  During this time (early 2013-early 2014) it saw a meteoric rise in its stock by more than 10-fold.

Management got so caught up by their own campaign of pushing Arrowhead Research as an HBV stock that they set themselves up for failure by setting overly ambitious goals for that program. 

As a result, the stock plummeted almost as rapidly as it had risen first by the Fed-induced biotech sell-off in spring 2014, and especially after first clinical results (see here and here) of ARC520 in HBV-infected patients did not live up to the hyped-up expectations.  90% HBsAg knockdowns had been the stated goal for a single-dose 2mg/kg.  This was despite preclinical studies which suggested that more than 2mg/kg of the endosomolytic DPC component was needed to achieve such robust knockdowns.

While my jaws certainly dropped in disbelief when I heard this, in my mind this has to be chalked up to a lack of full understanding of their company's own technology rather than gross misconduct.

…but for me it has always been subQ, subQ, subQ, extrahepatic

While I very much liked the fact that Arrowhead Research was at the very cutting edge of the ‘HBV-The-Next-HCV'  wave, what originally got me all fired up about Arrowhead Research was an OTS presentation in late 2012 where they presented impressive (robust and long-lasting) knockdown in non-human primates with a subcutaneous, most likely single-molecule version of their DPC delivery technology.  Knockdown that was more potent than anything out there (Alnylam GalNAc-STC at the time) combined with the convenience of subcutaneous instead of intravenous administration.  The latter is practiced with their more advanced two-molecule DPC version underlying ARC520 and ARC-AAT in the clinic already.

Single-molecule DPCs should also be the foundation for reaching tissues beyond the liver, making the transition back to single-molecule DPC all the more valuable.  Given that the liver has been solved for oligonucleotide therapeutics with Alnylam’s and ISIS’ GalNAcs, opening up new tissues to RNAi is obviously all the more attractive.

It is unclear what held the company back from taking the non-human primate achievements almost 3 years ago into the clinic.  Scale-up manufacturing issues rank highest on my list of possibilities.

Company guides for 2015 IND for either subQ liver or extrahepatic i.v. candidate  

During this week’s Q4 earnings conference call, the company indicated that they have finally achieved long-awaited technological breakthroughs so that we can now expect them to file an IND for either a liver target using for the first time a subcutaneous DPC formulation or an IND for an extra-hepatic target. 

Correction/clarification (2 Feb 2015): The company contacted me to clarify that what they said was that they will file an IND in 2015, and in addition to that, nominate a new development candidate that will either be extrahepatic or a subQ liver candidate.

Interestingly, if the extrahepatic program should make it to the finish line first, it would still be administered intravenously, which leads me to believe that it is a target in the kidney which I consider the only other obvious target tissue amenable to 2-molecule DPC.  If the target cell is not the proximal tubule cell, it would suggest that Arrowhead has identified a GalNAc-ASGPR-type ligand-receptor pair for the kidney.

ARWR 2015 playbook

Be it as it may, the prospect of both a highly competitive delivery technology for the liver and the availability of a new target tissue makes this a highly attractive re-entry point into ARWR.  At $6+ down from the mid $20s not even a year ago and with almost half of its valuation in cash, I do not see much downside from the 3-4mg/kg results of ARC520 to be reported in Q2 2015. 

Personally, I expect an 80-90% knockdown at 4mg/kg, but since I have no idea how the market would react to an 80% knockdown, the results are a coin toss to me, but with a somewhat larger upside (up to $14) than downside (down to $5) from here.

If the stock trades down, but somewhat dependent on the safety data, it may be an opportunity to snap up ARWR for the ARC-AAT phase I results coming up by the end of the year.  I consider ARC-AAT a very robust program with increased knockdown potency compared to ARC520 and much less ambiguity around what an X% knockdown means.

 

Right now, Arrowhead Research is an ARC520-only story and that should change once ARC-AAT becomes recognized as a medically and commercially very attractive product candidate (e.g. an orphan indication with an estimated 100.000 patient population in the US alone).  And I am convinced that I'm not the only investor to recognize subQ and extra-hepatic as the ultimate value drivers for ARWR all of which could propel the stock back to its 2014 highs over the next year.