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Arrowhead Pharmaceuticals, inc (NASDAQ:ARWR)
Q3 2021 Earnings Call
Aug 5, 2021, 4:30 p.m. ET

Contents:

  • Prepared Remarks
  • Questions and Answers
  • Call Participants

Prepared Remarks:

Operator

Ladies and gentlemen, welcome to the Arrowhead Pharmaceuticals 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.

Vincent Anzalone -- Vice President of Investor Relations

Thank you. Good afternoon everyone. Thank you for joining us today to discuss Arrowhead's results for its fiscal 2021 third quarter ended June 30, 2021. With us today from management are President and CEO, Dr. Christopher Anzalone, who will provide an overview of the quarter; Dr. Javier San Martin, our Chief Medical Officer, who will provide an update on our pipeline; and Ken Myszkowski, our Chief Financial Officer, who will give a review of the financials. In addition, James Hassard, our Chief Commercial Officer and Dr. James Hamilton, our Senior Vice President of Discovery and Translational Medicine, will be available during the Q&A session of today's call.

Before we begin, I would like to remind you that comments made during today's call 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 fact, including without limitation those with respect to Arrowhead's goals, plans and strategies are forward-looking statements. These include statements regarding our expectations around the development, safety and efficacy of our drug candidates, projected cash runway, the receipt of future milestone and licensing payments and expected future development and commercialization activities. These statements represent management's current expectations and are subject to numerous risks and uncertainties that could cause actual results to differ materially from those expressed in any forward-looking statements. For further details concerning these risks and uncertainties, please refer to our SEC filings, including our most recent annual report on Form 10-K and subsequent quarterly reports on Form 10-Q. Arrowhead disclaims any intent and undertakes no duty to update any of the forward-looking statements discussed on today's call.

With that said, I'd like to turn the call over to Christy Anzalone, President and CEO of the company. Chris?

Christopher Anzalone -- President & Chief Executive Officer

Thanks Vince. Good afternoon everyone and thank you for joining us today. The fiscal third quarter and the period since our last conference call has been incredibly busy for Arrowhead. We made important advances in several of our development programs. This includes discovery stage programs and early, mid, and later stage clinical programs. It also includes programs from existing partnerships as well as a new business development transaction.

As a platform company, there are a few areas of critical importance where we focus our attention. First, we need to always push the boundaries of what is possible and make our TRiM platform better. Second, we need to expand the early stage pipeline rapidly and efficiently with new clinical candidates, as this will be an important source of growth in the future. Third, we need to move our mid and later-stage pipeline programs through clinical studies, as it gets closer to our goal of bringing important new medicines to patients without adequate treatment options. And lastly, we need to selectively use partnering to expand the reach and maximize the value of our TRiM platform and bring in non-dilutive capital that helps to fund our internal development. I think we are doing well in all these areas.

Let's take a moment to briefly review some key events in the last quarter that are good examples of this. For our discovery and early stage clinical pipeline, we had a very productive quarter. We completed discovery and optimization work on two new pulmonary programs and nominated them both as clinical candidates. They are now in the IND-enabling stage, which includes GLP toxicology studies and manufacturing of drug product for clinical studies. We have not yet disclosed the gene and disease targets, but we will be talking more about these programs later in the year.

We also presented very promising preclinical data on ARO-DUX4, our first muscle-targeted program being developed as a treatment for patients with facioscapulohumeral muscular dystrophy, or FSHD, at the 28th Annual FSHD Society International Research Congress. The data show that the TRiM muscle delivery platform can achieve functional delivery to various types of skeletal muscle and achieve deep, durable and dose-dependent knockdown of target genes. In addition, ARO-DUX4 improved multiple measures of FSHD-like muscle phenotype in relevant preclinical animal models. As DUX4 expression is recognized as the cause of muscle pathology in FSHD patients, Arrowhead believes that the selective targeting and knockdown of DUX4 using RNAi may prevent or reverse downstream myotoxicity and lead to muscle repair and improvement in muscle function in patients. There are currently no effective treatments specifically for FSHD, so patients need new therapeutic options that address the root cause of the disease.

We have been pushing aggressively toward the clinic with ARO-DUX4 as well as the two new pulmonary candidates we nominated this year. We expected to file CTAs for all 3 of them by the end of the year, but securing timely slots at CROs for IND-enabling toxicology studies has been challenging, so scheduling on the CTAs will be pushed into the first half of next year. That is unfortunate, but we have seen this become more of a bottleneck in the industry since the beginning of the pandemic. We have continued work on a number of other early programs and I am pleased to announce a previously undisclosed target.

We recently nominated ARO-C3 as a hepatocyte-directed candidate against complement C3. Overactivation of the complement cascade is thought to be causative of a number of diseases including paroxysmal nocturnal hemoglobinuria and C3 glomerulopathy and complement mediated injury is involved in many other conditions, including IgA nephropathy as well as many other renal, vascular, hematologic and neurologic conditions. Complement C3 is a central node in all three of the complement pathways including the classical, lectin and alternative pathways of complement activation, and it has recently been shown that inhibition of C3 can be both safe and effective in the treatment of complement mediated diseases.

We have a strong track record in TRiM-enabled hepatocyte-directed candidates, including ARO-HBV, ARO-LPA, ARO-AAT, ARO-ANG3, ARO-APOC3, and ARO-HSD. Clinical data from these programs gives us confidence that positive non-clinical data from the ARO-C3 may translate well in humans. We believe that an siRNA capable of substantially reducing C3 levels for 3 months or more could be the modality of choice for C3 inhibition and we expect to file a CTA for AROC3 by the end of the year. During the quarter, we also announced positive interim data for two of our early stage clinical programs, ARO-HIF2 and ARO-HSD.

I will start with ARO-HIF2, which is our first tumor-targeted program being developed as a potential treatment for patients with clear cell renal cell carcinoma, or ccRCC. To-date, investigational ARO-HIF2 has been generally well tolerated at doses of up to 525 milligrams weekly. The study has now progressed to a dose of 1,050 milligrams weekly, which is currently enrolling and dosing patients. We believe that in the first two dose cohorts ARO-HIF2 is showing clear signs of meaningful target engagement and potentially some early signs of efficacy in at least one patient.

Specifically, the HIF2a protein H-score was assessed via immunohistochemistry. 9 of 17 patients had tumor samples that could be evaluated and 7 of those 9 demonstrated reductions in HIF2a protein H-scores. These reductions ranged from minus 9% to minus 82% with a mean reduction of minus 48%. In addition, one subject had a partial response with approximately 65% tumor shrinkage and 5 subjects had a best response of stable disease. We think these early results in a heavily pre-treated population are encouraging for ARO-HIF2 and our tumor-targeted platform broadly. We also presented positive interim data for ARO-HSD being developed as a potential treatment for patients with liver diseases, such as NASH at the EASL International Liver Congress.

ARO-HSD was well tolerated in healthy volunteers given the single dose at 25 milligrams, 50 milligrams, 100 milligrams or 200 milligrams and in 5 patients with suspected NASH given a 100 milligram dose of AROHSD on Days 1 and 29. All 5 patients with suspected NASH showed a strong pharmacodynamic effect as measured by liver biopsy at Day 71. HSD17B13 protein was reduced by 92% and 97% in two patients, while the other three patients' Day 71 measurements were reduced below the lower limit of quantitation. Importantly, ALT showed a mean reduction from baseline of 46%, with all patients showing reductions ranging from 26% to 53%. We believe that ARO-HSD is the first investigational therapeutic to demonstrate robust inhibition of hepatic HSD17B13 mRNA and protein expression. We are also highly encouraged to see ALT levels drop significantly following just two doses of ARO-HSD.

In addition to progress on our early stage pipeline, we also achieved some important milestones for our mid and later-stage pipeline. I will start with our cardiometabolic programs, ARO-APOC3 being developed as potential treatment for hypertriglyceridemia and ARO-ANG3 being developed as a potential treatment for mixed dyslipidemia. We recently started two Phase 2b studies, one for each program. We intend to initiate 4 or more studies across the two programs, including a Phase 3 study. Javier will give more details about the studies that have already started dosing in a few minutes, but we believe the studies together will give us a robust picture on the pharmacologic activity of each medicine in various target patient populations. We are intending to identify the optimal dose and dose intervals to enable us to move confidently into multiple Phase 3 studies.

In addition to our cardiometabolic programs, we had multiple important events in the last quarter for ARO-AAT, also known as TAK-999, being co-developed with Takeda as a treatment for the rare genetic liver disease associated with alpha-1 antitrypsin deficiency. First, we presented additional positive interim 48-week liver biopsy results at the EASL International Liver Congress. These results demonstrated that ARO-AAT treatment led to rapid improvements in multiple measures of liver health, including fibrosis, with substantial and sustained reductions in the level of mutant AAT protein. Mutant AAT protein has been identified as the cause of progressive liver disease in patients with alpha-1 antitrypsin deficiency.

ARO-AAT treatment was generally well tolerated after up to 1 year of treatment. This is very important data and suggests to us that the drug is doing what it is designed to do and that removing the mutant AAT protein can give the liver a chance to begin the healing process, even when intervening in patients with late-stage liver disease. We and our partners at Takeda were thrilled to see these results and we have received similar responses from physicians and others in the alpha-1 treating community. We also fully enrolled the ARO-AAT Phase 2 SEQUOIA study, with the 40th patient being dosed recently. Combined with the various cohorts in the open-label 2002 study, we will have paired biopsies from approximately 50 patients receiving various dose levels and various treatment durations.

Lastly, for ARO-AAT, we were granted Breakthrough Therapy designation by the U.S. FDA. ARO-AAT was also previously granted Orphan Drug designation and Fast Track designation from the FDA and Orphan designation from the European Commission. Our goal is to expedite the development path of ARO-AAT and each of these important designations provide potential ways to achieve that. We will work with regulatory authorities and our partners from Takeda to identify the best path to bring this important drug to patients quickly.

Now, moving on to progress that we've made with partnering, as I mentioned, we believe a platform company should use partnering selectively to expand the reach and maximize the value of the platform technology and to bring in non-dilutive capital that helps to fund internal development. This is a key component of our business strategy and an area where we have seen important recent progress. The collaboration with Janssen, which was executed toward the end of 2018, for ARO-HBV against chronic hepatitis B infection, included an option on 3 additional programs. During the previous quarter, Janssen delivered written notice of its intent to exercise its option right for the first of those programs, ARO-JNJ1. This earned Arrowhead a $10 million option exercise fee and signals Janssen's intent to move forward with clinical studies.

Also, during the quarter, we announced a global collaboration and license agreement with Horizon Therapeutics for ARO-XDH, a previously undisclosed discovery-stage candidate being developed by Arrowhead as a potential treatment for people with uncontrolled gout. Arrowhead received $40 million as an upfront payment from Horizon and is eligible to receive up to $660 million in potential development, regulatory and commercial milestones and is further eligible to receive royalties in the low to mid-teens range on net product sales. Horizon will receive a worldwide exclusive license to the therapeutic and will be wholly responsible for clinical development and commercialization. This is a great example of an attractive partnering opportunity. It expanded the reach of our technology to an area that we had not intended to enter independently and brought in non-dilutive capital. It also brought in needed expertise in the gout field to help understand the disease, the clinical path, the tremendous unmet treatment need, and a dominant player in the space with an existing commercial organization. For all these reasons, we thought Horizon was the ideal partner and the deal made perfect sense for both of our companies. We look forward to working closely with Horizon as we advance this potential new therapy for patients in need.

As you've heard, this was a busy quarter with lots of exciting events. However, drug development doesn't progress in a straight line and invariably there are surprises. Sometimes these surprises lead to leaps forward, such as the faster than expected liver healing in our ARO-AAT program and sometimes these surprises can be more unwelcome. We experienced the latter in the ARO-ENaC program, our candidate being developed as a potential treatment for cystic fibrosis last quarter.

To review, we voluntarily paused the clinical study of ARO-ENaC after receiving a preliminary update from an ongoing chronic toxicology study in rats that contained unexpected signals of local lung inflammation. Because of this preliminary update, we instructed investigators to pause new screening, enrollment and any further dosing of investigational ARO-ENaC pending additional data from the ongoing chronic rat toxicology study and an additional ongoing chronic primate toxicology study. We have not seen any concerning safety or tolerability signals in people enrolled in the AROENaC1001 study. However, we place the safety of patients that participate in our clinical trials above all else, so we will continue to keep the ARO-ENaC clinical study on pause for now. We do not yet have full data back from the toxicology studies nor from additional studies that we are conducting internally, so we do not yet know the extent of the findings. We are investigating this fully and are still in the information gathering stage. We should know more in the coming weeks and months and we intend to provide an update when we are able.

With that overview, I'd now like to turn the call over to Dr. Javier San Martin. Javier?

Javier San Martin -- Chief Medical Officer

Thank you, Chris and good afternoon everyone. I want to give an update on our clinical studies and provide details on the design of a couple of our newest studies. First, I will discuss ARO-HIF2, which is designed to inhibit the production of HIF2a to treat clear cell renal cell carcinoma, or RCC. We were encouraged by the positive interim results from the first two cohorts of AROHIF21001, a Phase 1b dose-finding clinical study in 3 cohorts with advanced clear cell RCC. We are currently enrolling cohort 3, which is designed to include up to 10 patients who will receive a weekly IV infusion of 1050 milligrams of ARO-HIF2.

The study is designed to evaluate the safety of ARO-HIF2, to determine the recommended Phase 2 dose and to assess pharmacokinetics and preliminary efficacy, based on RECIST and post-dose tumoral expression of HIF2-alpha and HIF associated genes. Patients will continue to receive weekly ARO-HIF2 indefinitely until they experience disease progression, have a complete response or they discontinue. Our intention is to share additional interim data from this study, including data from cohort 1, 2 and initial results from cohort 3 at an appropriate medical meeting in the future. We have not yet selected the intended meeting.

The next program I want to detail is ARO-HSD, our investigational candidate for the potential treatment of alcohol and non-alcohol related liver disease. We think the interim data we presented at EASL was highly encouraging and in fact, our presentation was highlighted in the EASL Official Scientific Press Conference on NAFLD and NASH. It was exciting to see ALT levels drop significantly following just two doses of ARO-HSD. We expected a high level of target gene knockdown, because our TRiM system has been extraordinarily consistent across our different liver directed programs. But the improvement in ALT at this early time point was very welcome surprise. These data and the strong genetic evidence of HSD17B13 as a potential therapeutic target provide us with increased confidence as we design further clinical studies for ARO-HSD.

We are thinking about innovative designs that seek to answer key questions about the medicine, the disease and the mechanism of HSD17B13 inhibition and what early signs of improvement may look like. We are approaching this in a similar way to how we approach ARO-AAT. In the meantime, we are still conducting the Phase 1/2 in patients with NASH or suspected NASH and we are happy to report that the study is fully enrolled. As Chris mentioned, we started dosing in two Phase 2b studies of our cardiometabolic candidates, ARO-APOC3 and ARO-ANG3 during the last quarter. I will give a brief description of these study designs, so you all can think through potential timing. We intend to initiate additional studies shortly and we will provide details on the design of the additional studies when they start.

For ARO-APOC3, we initiated AROAPOC3-2001, a double-blind, placebo-controlled Phase 2b study to evaluate the efficacy and safety of ARO-APOC3 in adults with severe hypertriglyceridemia, or SHTG. Three dose levels of AROAPOC3, 10 milligrams, 25 milligrams and 50 milligrams will be evaluated against placebo in participants who have mean fasting triglycerides of greater than or equal to 500 mg/dL at screening. A total of approximately 300 participants will be enrolled in the study. All dose cohorts will enroll in parallel with 100 participants per dose cohort randomly assigned in a 3:1 ratio to receive ARO-APOC3 or placebo. Each participant will receive subcutaneous injections on Day 1 and Week 12. The duration of the study is approximately 54 weeks from screening to the week 48 end-of-study examination.

The primary objective of the study is to evaluate the safety and efficacy of both ARO-APOC3 in adults with SHTG and to select a dosing regimen for later stage clinical studies in this patient population. For ARO-ANG3, we initiated AROANG3-2001, a double-blind, placebo-controlled Phase 2b study to evaluate the efficacy and safety of investigational ARO-ANG3 in adults with mixed dyslipidemia. Three dose levels of ARO-ANG3 50 milligrams, 100 milligrams and 200 milligrams will be evaluated against placebo in participants with mixed dyslipidemia who had the following at screening: an LDL-cholesterol greater than or equal to 70 mg/dL or non-HDL-cholesterol greater than or equal to 100 mg/dL and mean fasting triglycerides between 150 and 500 mg/dL. A total of approximately 180 participants will be enrolled in the study. All dose cohorts will enroll in parallel with 60 participants per cohort randomly assigned in a 3:1 ratio to receive a subcutaneous injection of ARO-ANG3 or placebo on Day 1 and Week 12. The duration of the study is approximately 42 weeks from screening to the Week 36 end-of-study examination. After completing the Week 36 visit, participants will be eligible to continue in an open-label extension study. The primary objective of the AROANG3-2001 study is to evaluate the safety and efficacy of ARO-ANG3 in adults with mixed dyslipidemia and select a dosing regimen for later stage clinical studies in this patient population.

I will now turn the call over to Ken Myszkowski, Arrowhead's Chief Financial Officer. Ken?

Ken Myszkowski -- Chief Financial Officer

Thank you, Javier and good afternoon everyone. As we reported today, our net loss for the quarter ended June 30, 2021 was $29.9 million or $0.29 per share based on 104.1 million fully diluted weighted average shares outstanding. This compares with net loss of $13.6 million, or $0.13 per share on 101.8 million fully diluted weighted average shares outstanding for the quarter ended June 30, 2020.

Revenue for the quarter ended June 30, 2021 was $45.9 million compared to $27.4 million for the quarter ended June 30, 2020. Revenue in the current period primarily relates to the recognition of a portion of the $300 million upfront payment received under our collaboration agreement with Takeda as well as a $10 million option exercise payment received from Janssen for the ARO-JNJ1 program in May 2021.

Revenue for the Takeda agreement will be recognized as we continue to work toward completing our performance obligations of managing clinical trials in process and certain manufacturing related services. The remaining $230 million of revenue associated with the Takeda collaboration is anticipated to be recognized over approximately 2 years. Any additional milestones achieved with our collaboration partners would be additive to this projection. Revenue in the prior period primarily related to the recognition of a portion of the milestones received from our license and collaboration agreements with Janssen. Our performance and revenue recognition under the Janssen agreement for HBV is substantially complete.

Total operating expenses for the quarter ended June 30, 2021 were $77.8 million compared to $43.3 million for the quarter ended June 30, 2020. This increase is primarily due to increased candidate specific and discovery R&D costs as the company's pipeline of clinical candidates has both increased and advanced. Net cash used by operating activities during the quarter ended June 30, 2021 was $29.6 million, compared with net cash used by operating activities of $33.4 million during the quarter ended June 30, 2020. The key driver of this change was the $10 million option exercise payment received from Janssen for ARO-JNJ1 program in May 2021. Excluding any potential milestones from our collaboration partners, we estimate our cash burn run-rate to be $50 million to $60 million per quarter.

Turning to our balance sheet, our cash and investments totaled $644.7 million at June 30, 2021 compared to $453 million at September 30, 2020. An increase in our cash and investments was primarily due to the upfront payment received from Takeda offset by cash used by operating activities. In July, we also collected the $40 million upfront payment due under our recent collaboration with Horizon. Our common shares outstanding at June 30, 2021 were 104.2 million.

With that brief overview, I will now turn the call back to Chris.

Christopher Anzalone -- President & Chief Executive Officer

Thanks Ken. As I mentioned, we think we are making strong progress across the spectrum of activities required to be a successful platform company. We are innovating on the platform and pushing the bounds of what our TRiM technology can do. We are rapidly and efficiently feeding the early stage pipeline with new candidates that may be engines of growth for Arrowhead in the future. We are moving our mid and later stage clinical programs progressively closer to our goal of bringing important new medicines to the patients who need them. And lastly, we are selectively and responsibly using partnering and business development when it makes sense to do so. This last quarter saw important and tangible progress in all these areas. Thanks again for joining us today. I would now like to open the call to your questions. Operator?

Questions and Answers:

Operator

Thank you, Chris. [Operator Instructions] Your first question comes from the line of Maury Raycroft from Jefferies. Your line is open.

Maury Raycroft -- Jefferies -- Analyst

Thanks for taking my questions and congrats on the progress. I was wondering for the bottleneck for the CPA filings for DUX4 and the two pulmonary candidates. Can you comment on whether this has anything to do with waiting for additional preclinical data from the ENaC?

Christopher Anzalone -- President & Chief Executive Officer

It does not. It has to do with just finding slots of zeros. There is, we talked about this, I think a few conference calls ago that there is -- that since the pandemic there has been a non-human primate shortage. And also these pulmonary studies are a bit more difficult to do, because there is not many CROs that do come in. So given all that we just -- we have just had a bit of a bottleneck. And so we will get these done and just that we are going to get them done a quarter or two later than we had hoped.

Maury Raycroft -- Jefferies -- Analyst

Got it. Okay. And then also just wanted to check on if you are providing a status update on how that ENaC NHP studies going and you mentioned you may know more in the next few weeks and months, is it fair to assume that there could be an update on this and 4 to them? And in the next update, are you going to provide the some of the clinical data that you saw?

Christopher Anzalone -- President & Chief Executive Officer

Yes. So I just don't know. So with respect to the tox data, I just don't know when we are going to have better clarity, we are not going to have the NDP data till toward the end of the year. And so that will be a black box until then. We haven't yet that's still ongoing and so there is just no data there yet. We don't have final reports for the development piece of that. We are -- that's still ongoing. We just got an interim update, which caused us to press pause and now we are doing some other internal experiments. And so I can't give you good guidance on when we are going to do something, we are working on it right now. And I think beyond that, it doesn't make sense for us to talk about the clinical program until we have a better idea about where this is going to go and how quickly we might be able to get back on track if in fact, that's going to work out.

Maury Raycroft -- Jefferies -- Analyst

Okay, that makes sense. And last question for me just Arrowhead to the tox data and the fact that the RCC looked good, at this point, do you have more insight into the relationship between knockdown and related tumor activity and how do you think actually could change at higher dose?

Christopher Anzalone -- President & Chief Executive Officer

So we don't -- so with respect to the first question we don't yet have anymore information. With respect to the second question, I don't know fully, we are seeing this only -- we are looking at this in real time and we haven't seen data from the -- from a higher dose yet. So we will see where that goes. What was encouraging to me at least was that it appears that we are on the board here, we are getting good target engagements, it appears we are getting knocked down. So now, let's just see where this goes. I don't -- I would not expect a rapid sort of physiological response, if you will, with respect to tumor shrinkage and such through this pathway that may take a bit longer. So, the fact that we are seeing right now some knockdown suggest to us that our platform is working and so now we just need to see how that's going to go going forward.

Maury Raycroft -- Jefferies -- Analyst

Okay, that's helpful. Thanks for taking my questions and I will hop back in the queue.

Christopher Anzalone -- President & Chief Executive Officer

Sure. Thanks, Maury.

Operator

Thank you. Your next question comes from the line of -- from Alethia Young of Cantor. Your line is open.

Unidentified Participant

Hi, this is [indecipherable] on for Alethia and thank you for taking our questions. We are wondering if you could share more on your DUX4 program and how it compares to competitors? And also, if there is any read through from the Phase 2b results for Losmapimod, which missed on the primary endpoint in change with DUX4?

Christopher Anzalone -- President & Chief Executive Officer

Yes. So I will let James comment on that. I don't -- well, I will let him comment about I don't know that there is read through with the other one, because it's different. It's different compound entirely, of course, but James?

James Hassard -- Chief Commercial Officer

Sure. Maybe I will take the first question first about the how we compare with the competing programs. There is not a whole lot out there. With regards to the other oligo programs, the targeted anti-sense programs are all preclinical and there is really not much data available. And so the primary difference would be the way that we target the muscle cells that we use a peptide targeting ligand versus their antibody or antibody fragment approach. So that's -- I think that's the main difference as far as comparing and there is really no way to compare efficacy or knockdown levels as the other competing programs have not shared any data at this point. And then the other question was around the Fulcrum read-through set right. Yes, it's tough to say. I mean, it's a very different compound different mechanism. I think they did highlight the challenges associated with a biopsy study in this population. And with this specific target, where there is this sort of stochastic expression of the target that maybe difficult to catch or to monitor, if you will, with biopsy. And so we will look at downstream gene expression, but we will likely also look at other parameters that might help us select a dose for later stage clinical studies.

Unidentified Participant

Yes.

Ken Myszkowski -- Chief Financial Officer

In this study, I wanted to add another comment about this data, which I think that despite the biomarkers, the clinical data in semester was positive. So I think the target still is in a good place. Because if you look at the PLL and the physical function there is a number of products that were statistically significant, we don't know how clinically relevant dose changes is. And we are looking at that to try to see if some of those changes correspond with the minimal relevant changes and that I think will help us to understand this. So, I think there is a mix of results here despite the biomarker now being positive. I mean, it's clinical sciences of potential improvement in this patient population, which I think is excellent for the pathway.

Unidentified Participant

Okay, that's helpful. Thank you.

Christopher Anzalone -- President & Chief Executive Officer

Thank you.

Operator

Thank you. Your next question comes from the line of Esther Rajavelu from UBS. Your line is open.

Esther Rajavelu -- UBS -- Analyst

Hey, thank you for taking my question. I have two. One on ENaC, so it's historically been a tough target, but what are some takeaways from the tox signals that you are seeing? Is it specific to the lung or is there evidence of exposure in other tissues? And what would your considerations be if you find that the tox is limited to the lung?

Christopher Anzalone -- President & Chief Executive Officer

So, let me just say two words and I will hand it over to James on this. The tox that we saw whether we heard about, again, we haven't had a final report on this rat study. So we had a limited data, but what we understand is that it was local lung inflammation. We don't see -- we didn't see broader issues. We don't know if that's species specific, because as I said, we don't have the NHP data yet. We don't know if it is sequence specific or is target specific. There is -- we are really just starting to get into this.

James Hassard -- Chief Commercial Officer

What was the other part of the question?

Esther Rajavelu -- UBS -- Analyst

The other part of the question was, if you sort of consistently see that the toxes when you get the NHD data, if you see the toxes limited to the lung, would it -- I mean, how would you interpret that, is it specific -- would it -- is that a good thing, because the drug is getting to the lung and you just have to find another target that works maybe in a different or do you -- or would you have to go back and change the chemistry?

James Hassard -- Chief Commercial Officer

Well, if the tox being limited to the lung, as Chris has stated is not surprising. I mean the systemic bioavailability with inhalational oligos is not that great. So it's not unexpected that we would only see tox in the lung. I think it depends on what we would see in the final results from the rat and then the NHP study in terms of what the toxicity is and at what dose levels and dose frequencies there, again, depending on the results and we don't have these results, yet, there maybe an opportunity to resume the study as is or to amend take a look at different dose levels, different dose intervals.

Christopher Anzalone -- President & Chief Executive Officer

Right. And following to that, remember that we dose this, we can dose this reasonably high, but also we dose it relatively frequently. And so to James' point or as he alludes, if we are -- if this appears to be clean in the NHPs, it could be that we have an opportunity just to space out the dosage is a bit more. That's all speculation. Let's see where the data come in and we go from there.

Esther Rajavelu -- UBS -- Analyst

Got it. Thank you. And then on AAT, are you still on track to revisit the registrational trial design with the FDA and I think you said in the third quarter, late summer or thereafter?

Christopher Anzalone -- President & Chief Executive Officer

Javier?

Javier San Martin -- Chief Medical Officer

And you say the initiation of the Phase 3 study?

Esther Rajavelu -- UBS -- Analyst

Yes.

Javier San Martin -- Chief Medical Officer

Part of the introduction, yes. So as you probably know, we have been granted with breakthrough designation about a week or 2 weeks ago. We are already working on the briefing document to engage in the first what is called multidisciplinary meeting, yes, in the Q3-Q4 timeframe.

Esther Rajavelu -- UBS -- Analyst

Thank you.

Christopher Anzalone -- President & Chief Executive Officer

Thank you.

Operator

Thank you. Your next question comes from the line of Joel Beatty from Baird. Your line is open.

Joel Beatty -- Baird -- Analyst

Hi, congrats on the progress. Couple of questions on the HIF2a program, the first is with the dose response in reduction of HIF2a seen in among those two doses in that study. And then I have a follow-up.

James Hassard -- Chief Commercial Officer

The dose response between the first two cohorts, yes, I think we are still in the process of dose escalating and analyzing all the data from the second cohort. A lot of those patients are still on drugs. So, I think it's too early for us to really give a clear answer on dose response.

Christopher Anzalone -- President & Chief Executive Officer

And a further complicating factor is that I may get these numbers wrong. So correct me if I'm wrong, we had of 17 individuals, I think we only had usable biopsy material from 9 of them. And so it may be difficult to know if we haven't just sponsored at this point. The only think I will add is that we did knockdown in both doses.

James Hassard -- Chief Commercial Officer

And in the press release we were just giving an overall top line on this. And so our intent, we said this in the prepared remarks is to present a more full dataset at an appropriate medical meeting, which will include the top dose level as well. So stay tuned on that.

Joel Beatty -- Baird -- Analyst

Yes, OK. That all makes sense and it is helpful. Sorry, just one follow-up on the -- you mentioned there is one responder with a fair response, are you able to share anything about the HIF2a reduction that was seen in the patients?

Christopher Anzalone -- President & Chief Executive Officer

Yes, not at this time. I think we can share that when we present the full dataset at an upcoming medical meeting.

Joel Beatty -- Baird -- Analyst

Great. Thank you so much.

Christopher Anzalone -- President & Chief Executive Officer

Thanks.

Operator

Thank you. Your next question comes from the line of Salveen Richter from Goldman Sachs Group. Sir, your line is open.

Unidentified Participant

Thanks for taking our question. This is Sonia on for Salveen. We were just wondering like beyond the pulmonary target and the muscle target, what other extra hepatic tissues would you be looking to go into on the forward?

Christopher Anzalone -- President & Chief Executive Officer

So, we have active programs in a number of areas. We have not disclosed other areas that the other effort that we are working on. So yes, just facing on that -- look, we have mentioned in the past though the CNS clearly is a target rich environments. So, it's a place we want to go at some point. We are not there yet, but there is a number of tissue types that we are looking at.

Unidentified Participant

Thanks.

Christopher Anzalone -- President & Chief Executive Officer

Sure.

Operator

Thank you. Your next question comes from the line of Luca Issi from Royal Bank of Canada. Your line is open.

Unidentified Participant

Great. Thanks for taking the question. This is Lisa on for Luca. Just one on A1AT, can you give us some directional color here on more with the ongoing dialogue with the FDA, now that you have Phase 2 designation, there maybe a scenario where the data from the 202 study and the first 36 patients from sequoia will be sufficient for accelerated approval? And I also have a follow-up on the ENaC.

Javier San Martin -- Chief Medical Officer

This is Javier. Yes, we are thinking about all of those options. Right now, we will need to focus on the first interaction. And typically, this first interaction as I say is a multidisciplinary meeting. We will touch upon different aspects of the filing process, discuss the Phase 3 study design, the approval endpoint, and the time to filing is going to be critical, but it's now a one-stop conversation, it's a process. So, it's a good thought and we will of course entertain that thinking and that potential step forward.

Christopher Anzalone -- President & Chief Executive Officer

And we have had really so far limited interactions with the FDA and particularly with the current division. But our interactions have been quite positive and collaborative. They clearly appreciate that this is an unmet medical need and I think that they are really interested in working with us to get this to patients who need us. And so we haven't had, so we are really excited to have this breakthrough designation. So, we can sit down and have these more in-depth discussions.

James Hassard -- Chief Commercial Officer

And to your point, breakthrough designation essentially opens the path to an approval based on the surrogate likely to translate into clinical benefit. And that's precisely what we will discuss. The next time around, there was a significant component of the breakthrough resignation briefing document. So, yes, we are going to talk about this throughout the process.

Unidentified Participant

Great. That's helpful. And then just one on ENaC, just wondering if you can talk about the doses at which you are seeing the tox result in rats and how those doses scale into humans? Just trying to figure out here whether the signal of -- the tox signal seen in rats was seen at maybe super therapeutic doses or at doses that scale within the 40 to 180 mg range that are being tested in humans? Thanks.

Christopher Anzalone -- President & Chief Executive Officer

Sure. And I appreciate the question. But look, it is -- it has been our policy not to talk about tox data, in particular, because we don't even have you have a final report here. We just -- we have just been given a small synopsis about part of a rat study. We don't even know anything about the NHP. So, we are unable to give you any more color on that at this point.

Esther Rajavelu -- UBS -- Analyst

Okay, got it. Thanks for taking the questions.

Christopher Anzalone -- President & Chief Executive Officer

Sure.

Operator

Thank you. Your next question comes from the line of Patrick Trucchio from HC Wainwright. Your line is open.

Patrick Trucchio -- HC Wainwright -- Analyst

Alright. Thanks. Good evening, just a couple of follow-up questions on the C3 program. Well, first, can you discuss what if any potential vendors are targeting C3 rather than C5? And secondly, do you know which indication or indications of the C3 program would initially focus on, when that clinical development could begin? And is this a program you would bring into clinical development on your own or would you seek a collaboration partner?

Christopher Anzalone -- President & Chief Executive Officer

I will answer the last of those questions and then I will hand the rest over to James. So, we do not have plans to seek a partner right now for this program. If you look that may change in the future, but right now we are having to take this forward. This is directly in our wheelhouse in terms of preclinical development. This is a directed construct. We feel good about going to clinic. And so let's see what the data look like. And then we can make a decision on partner versus non-partner at some point in the future. James?

James Hamilton -- Senior Vice President of Discovery & Translational Medicine

Yes, sure. I will take the first part of the question that I think was about C3 versus C5. So, C3 in the complement cascade is a central node that is involved in all three different components of that pathway, the lectin, the alternative and the classical pathways. So, if you can inhibit C3, you can really take out everything that's downstream of C3 and so the effects should be broadly applicable to various complement mediated diseases. Now, specifically to two interesting indications PNH and C3 glomerulopathy, that Chris mentioned during the earlier remarks. PNH is a disease that's been reasonably well treated with C5 inhibition. However, there is a component of that population that is refractory to treatment, due to extravascular hemolysis. That's primarily driven by C3. So, that residual population with the residual anemia, that's refractory to C5 inhibition, could be specifically treated with -- potentially treated with C3 inhibition. There is another population, that the C3 glomerulopathy patients where their disease is really driven by excess C3 activity in deposition of C3 fragments in the glomerular. So, that's really a C3 driven disease. Beyond those, there are other conditions that are where the disease is, complement mediated, and maybe not as specific to C3 as those other two conditions, complement mediated. And we think that C3 inhibition may have applicability in those other complement mediated diseases. So, I think that covers maybe both the first and the second question about C3 versus C5, as well as the other indications.

Patrick Trucchio -- HC Wainwright -- Analyst

And one other question was about when we can enter clinical development?

Christopher Anzalone -- President & Chief Executive Officer

By the end of the year. So, we will be filing CTA by the end of the year.

Patrick Trucchio -- HC Wainwright -- Analyst

Got it, that's helpful. And then just a follow-up on the gout program, can you tell us where ARO-DUX would fit from a gout treatment paradigm, and the potential cadence of the $660 million in potential milestones from price and so maybe something you could comment, when the program could be expect it to enter a clinical development?

Christopher Anzalone -- President & Chief Executive Officer

We can't say anything about that, about any of those actually. So the -- so we did not split out what the -- how the $660 million of potential milestone payments could be achieved. With respect to how this could fit into a clinical paradigm, this is one of the reasons we chose Horizon as a partner. This is their business and we work closely with them. But ultimately, this is their decision. And so I don't want to step on their toes and tell you something that we believe when this is really going to be their business. And with respect to what you asked and when they are going to begin the clinic, we don't know the answer to that. This is still an early program. We are just working out right now. And so it's, we still have ways to go.

Patrick Trucchio -- HC Wainwright -- Analyst

Got it. That's helpful. Thank you very much.

Christopher Anzalone -- President & Chief Executive Officer

You're welcome.

Operator

Thank you. Your next question comes from the line of Ted Tenthoff from Piper Sandler. Your line is open.

Ted Tenthoff -- Piper Sandler -- Analyst

Thank you everyone. And I just wanted to get a sense a little bit more on the new pulmonary targets. What are our gating factors, and is there anything you expect to learn from the ENaC program that could impact those programs come into the clinic. Thank you very much.

Christopher Anzalone -- President & Chief Executive Officer

Yes. So, that's a good question Ted. I don't know the answer to that. It's still just too early. We don't know what's going on with what happened in those rats in the ENaC program. And so until we have more information, I just don't know how that might read on future programs. I can't go, it slowed us down. We -- this is still we think a big opportunity for us. And we are still moving as quickly as we can. We are excited about these two new programs. We haven't talked about the gene targets. We haven't talked about the disease areas. I expect that we will maybe later this year. We were disappointed that we couldn't get the slots that we wanted to move this into the clinic this year. But that's just the way the world turns right now. And so we look forward to getting this in the clinic in the first half of next year. I will say that what we think we have seen, because again, I have always seen small data from that rat study. But what we have seen there has caused us to do a bit more work while we are waiting just internally on chronic studies. These are non-GLP talks, again these are just so. So, we understand a bit more internally on the other programs.

Ted Tenthoff -- Piper Sandler -- Analyst

And with respect to with the patients who have already been dosed. How do we anticipate hearing about that data? I know you are not dosing anyone going forward. But is that going to be [indecipherable] doing whether it's going to be informative? And is that something you would share publicly?

Christopher Anzalone -- President & Chief Executive Officer

Yes. And again, I am sorry. I can't give you a definitive answer on that. Just because we don't know, what's going to happen with that program. And if we can restart it, when we don't know, when we can restart it. So, until we have more information, we just would rather not give any sort of guidance one way or the other.

Ted Tenthoff -- Piper Sandler -- Analyst

I really understand. Yes. Totally understand. Awesome. Chris, thanks so much for the update and really a lot of great progress this year. So, I am excited for back half.

Christopher Anzalone -- President & Chief Executive Officer

Thank you, Ted.

Operator

Thank you. Your next question comes from the line of Keay Nakae from Chardan. Your line is open.

Keay Nakae -- Chardan -- Analyst

Hi, thanks. Yes. Chris, just following up on the new programs, so what are the similarities between the construct for those versus ENaC? I mean, obviously, you are going to have a different sequence for the targeted June. But are you using the same targeting ligand. And so help us try to better understand what the potential read across of risk is from the ENaC tox?

Christopher Anzalone -- President & Chief Executive Officer

Right. So, we are using the same formula again, as you said different sequences. I would expect that we will be using less material in the next two, because at least in animal studies, they both appear to be more potent than ARO-ENaC. Is that important, I don't know. But I believe that as well, I know, it's the case for animal studies. And we will see that translates into humans. And so if again, until we have more data, it's just too early to speculate on how that what we saw in the chronic tox, interacts, may translate to other sequences.

Keay Nakae -- Chardan -- Analyst

Okay, thanks for that. And then just for James, the biopsies that you received and the fact that some of them weren't used, but can you just further characterize that and how we think about the risks there going forward of not being able to get the data to do your assessments?

Christopher Anzalone -- President & Chief Executive Officer

James?

James Hamilton -- Senior Vice President of Discovery & Translational Medicine

Yes. So far maybe I will make one comment about the study design the protocol allows us to enroll up to a sufficient number of patients to get enough biopsies that we think are adequate -- paired biopsies to make to do our analyses. And as was described in the press release, the biopsy samples are not always analyzable. But so far in the first and second cohort, and then and so far in the third as well, we have been able to get enough biopsy samples to do the work that we need to.

Keay Nakae -- Chardan -- Analyst

Okay. Thanks.

Christopher Anzalone -- President & Chief Executive Officer

Yes. Thank you.

Operator

Your next question comes from the line of Mayank Mamtani from B. Riley. Your line is open.

Sahil Kazmi -- B. Riley -- Analyst

Hi, good afternoon. This is Sahil Kazmi on for Mayank. Thanks for taking our questions. Maybe a brief one on HIF2, could you provide any color on kind of how the enrollments been tracking maybe in the context of the program and maybe approval or just increased awareness on VHL disease associated with RCC?

Christopher Anzalone -- President & Chief Executive Officer

Yes. Enrollment has been actually really good in that program throughout. We have not seen any challenges with enrollment and all the slots have filled very rapidly. And so I know that the Merck study is ongoing, but it has not detracted from enrollment into this study.

Sahil Kazmi -- B. Riley -- Analyst

Okay. And then maybe on HBV, do you have any insight into kind of what forum J&J might present for the 24-week of treatment data from reads and/or any high level thoughts on kind of what we can incrementally learn from that study?

Christopher Anzalone -- President & Chief Executive Officer

Boy, no. I can't give any guidance on that. Look, we look forward to seeing those data, but I don't know what their plans are to be honest about where that could be presented.

Sahil Kazmi -- B. Riley -- Analyst

Got it. Thanks for taking my questions and congrats on the quarter.

Christopher Anzalone -- President & Chief Executive Officer

Thank you.

Operator

Thank you. Your next question comes from the line of Mani Foroohar from SVB Leerink. Your line is open.

Rick Bienkowski -- SVB Leerink -- Analyst

Hi, good afternoon. This is Rick on line for Mani. Thanks for taking our questions just two from us. So first, for HIF2, could you speak to some of the variability of knock down seen with data? I know there are a lot of data sets on value in tumors. So, some of this variability just due to the heterogeneity of tumors in general or it was something that could potentially be resolved by looking at higher doses or either earlier lines of patients?

Christopher Anzalone -- President & Chief Executive Officer

Yes. I think that you hit the nail on the head. I mean I think there is that heterogeneity of expression in the tumors and across from patient to patient. And also heterogeneity in between paired biopsies, you are not necessarily getting into the same area of the tumor. So, heterogeneity is definitely an issue and probably explains a good component of the variability.

Rick Bienkowski -- SVB Leerink -- Analyst

Alright. Got it. Alright. Thanks a lot. And one of the much more broad question, so just in general, I would approach to extrahepatic deliveries needs to be focused around integrates with specific ligand conjugates. Can you maybe speak to why these are so favorable to target other class of molecules? And if the company is currently exploring another targeting strategies pre-clinically.

Christopher Anzalone -- President & Chief Executive Officer

Yes. So, I will let James to go, has also been budgeted broadly. We are not an integrin targeting company. We are an R&D company. And so we tend to use what works best. And we are agnostic. We have done work with antibodies with antibody fragments, with peptides, with modules and such. And so, we just, we have ideas about what might work best, but ultimately, the data will tell us and so it just so happened that we have that, that interment based targeting has been quite good for us. So James?

James Hamilton -- Senior Vice President of Discovery & Translational Medicine

I will go with that, that we don't report works. And we went with integrin receptor ligen in pairs, not because that was our area of expertise, but because that was what was looking the best. And we continue. We have historically evaluated multiple different receptor ligand pairs and continue to do so. And I think we will continue to go with what works regardless of what the modality is, if it's an antibody or a small molecule or something else.

Rick Bienkowski -- SVB Leerink -- Analyst

Great, I appreciate all the detail.

Christopher Anzalone -- President & Chief Executive Officer

Yes. Thanks very much.

Operator

Thank you. There are no other questions on the queue. I will now turn the call over back to Chris. Please go ahead.

Christopher Anzalone -- President & Chief Executive Officer

Thank you all for joining us today and I hope you have a nice evening and afternoon.

Operator

[Operator Closing Remarks]

Duration: 58 minutes

Call participants:

Vincent Anzalone -- Vice President of Investor Relations

Christopher Anzalone -- President & Chief Executive Officer

Javier San Martin -- Chief Medical Officer

Ken Myszkowski -- Chief Financial Officer

James Hassard -- Chief Commercial Officer

James Hamilton -- Senior Vice President of Discovery & Translational Medicine

Maury Raycroft -- Jefferies -- Analyst

Unidentified Participant

Esther Rajavelu -- UBS -- Analyst

Joel Beatty -- Baird -- Analyst

Patrick Trucchio -- HC Wainwright -- Analyst

Ted Tenthoff -- Piper Sandler -- Analyst

Keay Nakae -- Chardan -- Analyst

Sahil Kazmi -- B. Riley -- Analyst

Rick Bienkowski -- SVB Leerink -- Analyst

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