Ladies and gentlemen, welcome to the Arrowhead Research Fiscal 2015 Second Quarter Financial Results Conference Call. Throughout today's recorded presentation, all participants will be in a listen-only mode. After the presentation, there will be an opportunity to ask questions. I will now hand the conference call over to Vincent Anzalone, Vice President of Investor Relations for Arrowhead. Please go ahead, Vince.

Thank you. Good afternoon, everyone. And thank you for joining us today to discuss Arrowhead's results for its fiscal 2015 second quarter ended March 31, 2015. With us today from management are President and CEO, Dr. Christopher Anzalone; Chief Operating Officer and Head of R&D, Dr. Bruce Given; and Chief Financial Officer, Ken Myszkowski. Management will provide a brief overview of the quarter and will then open up the call to your questions. Before we begin, I would like to remind you that comments made during today's call may contain certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements other than statements of historical facts, including without limitation those with respect to Arrowhead's goals, plans and strategies, are forward-looking statements. These include but are not limited to statements regarding the anticipated safety and/or efficacy of ARC-520, ARC-AAT, ARC-F12, and our other programs, as well as anticipated timing for study enrollment and completion and the potential for regulatory and commercial success. They represent management's current expectations and are inherently uncertain. Thus actual results may differ materially. Arrowhead undertakes no duty to update any of the forward-looking statements discussed on today's call. You should refer to the discussions under Risk Factors in Arrowhead's annual report on Form 10-K and the company's quarterly reports on Form 10-Q for additional matters to be considered in this regard. With that said, I’d like to turn the call over to Dr. Christopher Anzalone, President and CEO of the company. Chris?

Thanks, Vince. Good afternoon, everyone, and thank you for joining us today. In review of the previous quarter and period since our last call, we are very pleased with the progress we’ve made on several fronts. I will cover a few of the highlights now and then turn the call over to Bruce Given, our Chief Operating Officer and Head of R&D, to discuss our clinical programs in more detail. During the quarter, we acquired Novartis’ entire RNAi business. This portfolio of assets represents almost a decade of work by Novartis and gives us some important new capabilities. The portfolio includes the multiple patent families covering RNAi trigger design rules and modifications that we believe fall outside of key patterns controlled by competitors, combined with the chemistry portfolio constructed by Roche, we feel that we can work on any target an indication. In addition, Novartis' discovered novel intercellular targeting ligands that can enhance the activity of some RNAi triggers by targeting the RNA induced silencing complex or risk more effectively and improve instability once the risk is loaded, think of these and sophisticated RNAi activity enhancers. Also included was an assignment of Novartis' license from Alnylam Pharmaceuticals granting Arrowhead access to Alnylam intellectual property excluding delivery IP for 30 gene targets already chosen by Novartis' and lastly a pipeline of three candidates that were in active development and went through the rigorous Novartis' vetting process. We view this acquisition then as the addition of new tools to our already substantial RNAi toolbox and this feeds into our broad two pronged philosophy. First, we want to have the freedom to address any target and indication from an IP standpoint. Second, we want to have access to as many RNAi triggered structures and modifications as possible. In order to tune each candidates…

Thank you, Chris, and good afternoon, everyone. As you heard from Chris our clinical development and regulatory teams have been very busy recently and are doing a great work designing and managing our clinical studies. Chris touched on this but I would like to talk for a moment about the HEP-ARC 2001 study of ARC-520. As you recall this was a originally a single dose Phase2A study in e-antigen negative chronic HBV patients at two sites in Hong-Kong. We previously reported initial results from the first two dose cohorts at 1 mg/kg and 2 mg/kg and as of our last quarterly conference call we had enrolled an additional two dose cohorts at 3 mg/kg and 4 mg/kg. Observation periods are complete for these and the cohort remains blinded. We have since made protocol amendments to add three additional cohorts, two of which have received IRB approval to proceed and we expect a third to be approved as early as this month. We have already enrolled and dosed 7 of 8 patients in the first new cohort and hope to dose the last patient shortly. The second additional cohort is recruiting patients now, similarly we expect the third new cohort to enroll at a good pace once IRB approval is achieved. As you know we un-blinded the 1 mg/kg and 2 mg/kg cohorts last year in order to support an IND and other regulatory filings for multiple dose Phase2B studies. We expect to un-blind the entire Phase2A study which will include the 3 mg/kg and 4 mg/kg cohorts as well as the additional blinded cohort next quarter. We understand that many of you would like us to disclose data from the 3 mg/kg and 4 mg/kg cohorts now and we would also like to be able to discuss those. However un-blinding…

Thanks Bruce and good afternoon everyone. As we reported today, our net loss for the three months ended March 31, 2015 was 28.7 million or $0.51 per share based on 55.7 million weighted average shares outstanding. This compares with a net loss of 14 million or $0.31 per share based on 44.3 million weighted average shares outstanding for the three months ended March 31, 2014. Net cash used in operating activities during the second fiscal quarter was 16.4 million compared with 7.7 million in the prior year period and 24.2 million in the first fiscal quarter. Cash used in operating activities during the quarter of 16.4 million primarily composed of research and development cost, mostly program cost for ARC-520 and program cost for ARC-AAT, as well as R&D salary and wages and related discovery research cost. Total operating expenses for the three months ended March 31, 2015 were 29.7 million compared with 11.3 million for the three month ended in March 31, 2014. The increase in the operating expenses compared to the year ago period are heavily influenced by a non-cash charge of 10.1 million for acquired in process research and development costs, a component of the accounting related to the Novartis acquisition. Additionally, there were higher research and development expenses primarily drug manufacturing cost which increased 3.2 million during the period mostly related to ARC-520 as well as higher clinical cost which increased 1.2 million. Clinical costs have increased as we incur startup cost from our CRO related to the planned ARC-520 Phase2B studies. We also incurred cost for our second clinical candidate ARC-AAT of about 2.9 million, while ARC-AAT clinical trial costs in the comparable period were minimal. The primary drivers of the change in cash used in operating activities as compared to fiscal 2014 is consistent with the drivers of the change in operating expenses, aside from the 10.1 million for acquired in process R&D cost. The consideration provided to the acquisition of the Novartis assets was cash and stock. 25 million of stock was issued during the fiscal period and 7 million in cash was paid during the fiscal period. $3 million was paid in April of 2015. Turning to our balance sheet, at March 31 2015, including investments in fixed income securities, our cash and investments balance was 128.4 million, a decrease of 16.9 million from December 31, 2014. Our cash in investments at September 30, 2014 were 177.3 million. Our common shares outstanding at March 31, 2015 were $59.4 million which increased from 54.7 million at September 30, 2014 primarily due to the issuance of 3.3 million shares for the Novartis acquisition. Also at March 31, 2015 there were 15,652 shares of preferred stock outstanding. These preferred shares are convertible into 2.7 million shares of the common stock. Common shares outstanding, including the conversion of our preferred shares would be 62.1 million. With that brief overview, I’ll turn the call back to Chris.

Thanks Ken. During our last conference call we set out the list of goals for calendar 2015. We are measuring our execution versus those goals and our investors should do the same. We've already achieved three of the goals and are on schedule to reach several more. We still have a lot of work to do, but we believe the achievement of these goals among others will help to build long term value for our shareholders. There is a lot of exciting work going on at Arrowhead and the next several months are shaping up to be quite active indeed. We look forward to keeping you up-to-date on our progress and presented data from the long term chimp study and the ARC-520 clinical program at a special Analyst Day in next quarter. I'll now like to open the call for questions. Operator?

Thank you. [Operator Instructions] Our first question comes from Alethia Young with Deutsche Bank. Your line is open.

Hi, guys. Thanks for taking my questions. The first one, I guess, is with your update that you provided on the three new cohorts. Is it possible to give us a little bit more color around what are the hypotheses that you are studying there? As well like with the chimps, the nine new chimps, just a little more color around what is going on there as well. And then I have some follow-ups.

I think we'd like to hold that for when we do the Analyst day Alethia, as we sort of implied in the presentation there are competitively sensitive items here and while we are going to give -- our plan is to give out a lot of information during the Analyst Day, we would like to probably hold it for that last quarter otherwise we would have gone ahead and said here during the presentation what was included in those cohorts and I don't know Chris if you want to elaborate on that but.

No I think it's exactly right. We are as we said really excited about those new cohorts, I think it rounds out that Phase2A study nicely and the chimp study has been very exciting. We look forward to providing the live information during that day and it really is frankly far too much information to disclose any other way, but having a pretty indebt Analyst Day. So stay tuned that will be some time next quarter and I think it's an important day for us.

So have you guys said if it is single or multiple doses that you're going to be studying in the next cohorts?

We haven't said that.

Okay then moving on to maybe AAT. It seems like you got to your dose maybe a little bit earlier than what my expectations were at least. And then, maybe can you give us what the pre-clinical data suggested around how this correlates with what you are seeing in patients, so we can kind of get a read through maybe where you might see an application of dose again in patients?

We of course didn't know what the dose would be. This was crossover point, I guess was internally -- there probably would have been as many people at this doses for the next dose maybe. So, somewhere sort of in that range, we thought where there was a pretty good chance we've cross over. But in truth, this is now our second product in the clinic. So, we're starting to feel maybe that we see more of a clear trend to our animal data, but I think -- we felt the need to be cautious internally and over interpreting the animal data; but this feels like as we have said before that there seems to be a lot of similarity between humans and primates in sort of the dose responses that we see. Of course when it comes to a primate that's basically a normal gene and when we come to the patients they're going to be dealing with diseased genes, but I'd say this was in the ballpark of where we're hoping to start seeing that down and but it was hard to predict that we're going to actually see the knockdown to causes to go ahead and convert the patients here.

Back to ARC-520, your analyst day, are you expecting 3Q or 4Q for that?

Its next quarter, third quarter.

Our next question comes from Eun Yang with Jefferies. Your line is now open.

Hi this is [indiscernible] for Yang, thanks for taking the question. So for the multi-dose study and 520 is turning out 1 mg, are you going to meet see the data there before moving in to the 2 mg cohort?

So what the FDA wants to see, is they want to see, is they want to see the data from this 1 mg/kg U.S. study, they want to see the final study report from the Hong Kong HEP-ARC 2001 study and now we can say what the preclinical study they're interested in, they saw the interim data from the chimp work and as you might imagine they found that pretty interesting and then they want to see the report from that as well. So they want to see all that -- that's the data package they're looking for to deal with the partial or clinical hole.

. And also keep in mind that, that's not -- we don't expect that to be a limiting factor for our ex-U.S. studies and we believe we should be all the move reasonably quickly in Europe and Asia with those studies.

Our next question comes from Michael Yee of RBC Capital Markets. Your line is now open.

A couple quick ones. If you wanted to dose with interferon, do you need to start that in Phase1A or had you already gotten permission for that? Or can you do that? And is that where I think we are going in the three cohorts? I guess, is the first question.

We’re certainly not implying that the three cohorts have interferon in them, so that's not anything that we're implying but to come back to your question, we of course won’t know until we get a regulatory read but our belief is just as we have really been able to dose with NUCs we think, we got to be able to dose with interferon which is also standard for care in Hepatitis-B. So it is not our thinking that we’d have to go back to Phase 1 to study that combination before we could study it clinically in Phase2B. But we'll have to wait and see whether the regulators agree with us. So, that's our perspective and we met with the lot of investigators at EASL and that was their perspective as well.

Okay. Just to be clear, it is a standard approved drug. So it's not like you need to go back to ask permission for that to dose together with ARC-520, because I think that is certainly a regiment we would all be interested in looking at from a safety perspective with one dose. But you are not implying at all but you are going that way?

Mike, we have to get regulatory approval to do any study involving ARC-520, I'm just saying that we believe that the regulatory authorities, at least in certain geographies especially are going to be likely to allow us to dose on top of interferon, just as we believe that they're going to be comfortable with us dosing on top of NUCs.

Okay. I guess to follow-up with that, in the attempt to move to Phase2B with multiple doses, you laid out some of the stuff you are thinking about to do that in the U.S. In Europe, it does, or I guess O-U.S. it does seem a little more straightforward as you just commented. I guess, what do you think the gating factors are to starting that, whether that be in Hong Kong or other regions? How would are we thinking about timing there, to get multiple dose started outside the U.S.?

Well it’s a little hard to say because we’re still in the regulatory process, so it's easier to answer that question when you've got your regulatory green light like we have with the FDA for the U.S. study. We certainly have the sense that assuming we don't come up with any surprises chances are pretty good that we will start dosing over the summer but I don't want you take that as guidance, because guidance would imply more certainty then I can give any time I’m dealing with regulatory reviews, but it feels sensibly possible.

And importantly as Bruce said we are in that regulatory process right now, we’re having those discussions, so as we said in the prepared remarks we believe that this quarter we could start to see approvals to begin some of those studies.

Okay. Last question, sorry to come back to it, but coming back full circle. In the additional cohorts, this has to all do with the Phase2A, correct? This is all single dose stuff, correct?

Yes. This is the Hong-Kong study, this is the 2001 study we are talking about we have added three cohorts to that study.

We haven't said if it's one or multiple doses, however.

I see. Okay, thank you.

[Operator Instructions] Our next question comes from Ted Tenthoff with Piper Jaffray. Your line is open.

Thank you very much. Just a little bit more clarity. Should we expect data from both 3 mg/kg and 4 mg/kg cohort and also these new three cohorts next quarter and that is what you will be reporting at the R&D day?

Yes. So expect that and also expect the long term or at least some of the long term chimp data we're going to have an awful lot of data and we need to figure out how we're going to communicate that and when we are going to communicate that, but there will be an awful lot of data that we’ll be going over from all of those during the Analyst Day in next quarter.

How it is Ted. I mean there is always that tension between what you can do and not lose your ability to present it at big international meetings like AASLD, and EASL and to not be prevented from publishing while giving investors enough to really understand the basics of what’s in the data. So that's a tension that all of us in the industry face and we’ll do our best to give as much information as we can without giving so much that we’re precluded from scientific publication and presentation of the data. There is always that tension I'm sure you are well aware of that.

Good enough. Thanks, guys. Looking forward to the R&D day.

Okay. Thank you.

Thank you. I'm showing no further questions. I would now like to turn call back to Chris Anzalone for closing remarks.