Travere Therapeutics, Inc. (TVTX) Q3 2021 Earnings Report, Transcript and Summary

Good day and thank you for standing by and welcome to the Travere Therapeutics' Third Quarter 2021 Financial Results and Corporate Update Call. At this time, all participants are in a listen-only mode. Please be advised that this call is being recorded. [Operator Instructions] I would now like to hand the conference over to Mr. Chris Cline, Senior Vice President, Investor Relations and Corporate Communication. Please go ahead.

Thank you, Justin. Good afternoon and welcome to Travere Therapeutics third quarter 2021 financial results and corporate update call. Thank you all for joining us. Today’s call will be led by our Chief Executive Officer, Dr. Eric Dube. Eric will be joined for the prepared remarks by our Dr. Noah Rosenberg, Chief Medical Officer; Peter Heerma, our Chief Commercial Officer; and our Chief Financial Officer, Laura Clague. Dr. Bill Rote, Senior Vice President of Research & Development will join us for the Q&A session. Before we begin, I would like to remind everyone that statements made during this call regarding matters that are not historical facts are forward-looking statements within the Safe Harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements are not guarantees of performance. They involve known and unknown risks, uncertainties and assumptions that may cause actual results, performance, and achievements to differ materially from those expressed or implied by the statement. Please see the forward-looking statement disclaimer on the company’s press release issued earlier today, as well as the risk factors section in our Forms 10-Q and 10-K filed with the SEC. In addition, any forward-looking statements represent our views only as of the date such statements are made, October 28, 2021 and Travere specifically disclaims any obligation to update such statements to reflect future information, events or circumstances. With that, I’ll now turn the call over to Eric. Eric?

Thank you, Chris and by the way Happy Birthday today. Good afternoon everyone. I am proud of the progress made across all facets of our business during the third quarter. First, I am pleased to report that we achieved several significant milestones related to our goal of positioning sparsentan to ultimately become the new treatment standard for IgA nephropathy and FSGS if approved. In August, we reported that our pivotal Phase 3 PROTECT study of sparsentan in IgA nephropathy achieved its primary proteinuria endpoint with statistical significance in its prespecified interim analysis. The results exceeded our expectations by demonstrating a greater than three-fold reduction in proteinuria from baseline compared to those patients receiving the active control irbesartan. And at the time of the interim assessments, sparsentan was generally well-tolerated and consistent with the observed safety profile to-date. This is the first time a single non-immunosuppressive agent has demonstrated this magnitude of effect on proteinuria reduction in a large well-controlled study. And we know from our engagement with the nephrology community that a treatment with these attributes is precisely what physicians are seeking to help prevent progression to end stage kidney disease. I'm very pleased to report today that we've completed our pre-NDA interactions with the FDA for sparsentan in IgA nephropathy. Notably, the FDA agreed that the interim analysis from the PROTECT study support submission of an application for accelerated approval under subpart H. Based upon the agency's feedback and alignment on our structure of the planned NDA, we expect to submit our application for accelerated approval in the U.S. in the first quarter of next year. We also made meaningful progress on our sparsentan program for FSGS during the quarter. Most importantly, we gained alignment with the FDA on our plan to provide the agency with additional eGFR data from the ongoing DUPLEX study in the first half of 2022, which enables us to continue on the accelerated approval pathway for FSGS. If the additional eGFR data further strengthen the prediction of long-term benefit in the study, as we expect they should we anticipate submitting an NDA for accelerated approval for FSGs in the middle of next year. We are pleased that we now have a clear regulatory path to potential accelerate accelerated approval force percentage for both IgA nephropathy and FSGS in the U.S. And we look forward to achieving those submissions next year. I'm also pleased to share that we have formalized our plan to pursue a combined IgA nephropathy and FSGs am a submission for sparse entered in Europe. This strategic decision will allow us to pursue the most expedited path to making sparse internet available for both IgA nephropathy and FSGS in Europe, and we believe it will increase the probability of success for achieving optimal market access across regions. Additionally, this option allows us to potentially request accelerated assessment for the review process We will continue our engagements with the EMA and expect the MA application to be submitted mid next year. Once the planned additional eGFR data from the DUPLEX study can be incorporated, if supported. Also, as it relates to Europe, we were very pleased to recently enter into a joint collaboration and licensing agreement with Vifor Pharma for the commercialization of sparsentan in Europe, Australia, and New Zealand. This collaboration aligned the strength of two leaders in rare nephrology with a shared mission to making sparsentan, the new treatment standard for IgA nephropathy and FSGS if approved. And it significantly increases our probability of success across all launches, as it will allow us to have the dedicated focus needed for successful launches in these substantial markets. The collaboration also recognizes the value sparsentan can bring in Europe and strengthens our financial foundation with potential milestone payments totaling up to $845 million and royalties on sales in these regions up to 40%. We look forward to working closely with Vifor as they integrate sparsentan into their portfolio and prepare for potential launches in Europe, Australia, and New Zealand beginning of 2023. Beyond sparsentan, we continue to be encouraged by the potential for our novel pegtibatinase program in classical homocystinuria or HCU. We believe that it has the potential to become the first disease modifying therapy for the more than 7,000 people in the U.S. and Europe who are not adequately responding to current treatment options. We remain on track for a preliminary assessment from the ongoing Phase 1/2 trial now named to the COMPOSE study before year end. And we look forward to establishing next steps for the program if the data are encouraging as we expect. Lastly, I'd like to highlight the performance of our commercial organization in the third quarter. Our execution led to another quarter of year-over-year growth across all approved products, despite the ongoing challenging environment created by the COVID-19 pandemic. This performance underscores our confidence in the ability to successfully deliver sparsentan and pegtibatinase, if approved. Let me now turn the call over to Noah for the clinical update. Noah?

Thank you, Eric. I remain very pleased the progression of our pipeline of potential first-in-class therapies for people living with rare diseases. In the third quarter, we took meaningful steps towards advancing sparsentan towards potential approvals in both IgA nephropathy and FSGS. Most notably during the quarter, where the positive topline interim results from the ongoing pivotal Phase 3 study PROTECT study of sparsentan in IgA nephropathy. After 36 weeks of treatment, patients receiving sparsentan achieved a mean reduction of proteinuria from baseline of 49.8% compared to a mean reduction of proteinuria from baseline of 15.1% for irbesartan treated patients. This result was clinically meaningful and statistically significant with a P value of less than 0.0001. Preliminary eGFR data available at the top end of the interim analysis were consistent with our powering and indicative of a potentially clinically meaningful treatment effect after two years of treatment. And from a safety perspective, we continue to be encouraged at the time of the interim assessment, sparsentan here to be generally well-tolerated and it appeared consistent with a previously observed safety profile. These data built upon a robust data path and has helped shape sparsentan safety profile and demonstrated the potential for clinically meaningful proteinuria reductions across nearly 500 patients with IgA nephropathy and FSGS. Including several patients that have been on therapy more than seven years in the open label extension of the Phase 2 DUET study. This further supports our confidence that sparsentan has the potential to meet the clear need for a new therapeutic option to meaningfully reduce proteinuria over and above widely use ACE inhibitor and ARB treatments and to do so, while avoiding the long-term safety challenges associated with immune suppression. As Eric mentioned earlier, we recently completed our pre-NDA interactions for IgA nephropathy and we are very pleased with the successful outcome. The FDA's agreement that the interim analyses from the PROTECT study supports the mission of an application for accelerated approval under Subpart H was clear. With this feedback and alignment on the content and organization of our application, we will be continuing our NDA preparations with the expectation of submitting in the first quarter of next year. Our FSGS program also continued its forward momentum with a recent type A interaction, where we gained alignment with the FDA on our plan to provide the agency with additional eGFR data in the first half of next year to support a potential application for accelerated approval. At the time of the planned eGFR data cut, all patients remaining in the DUPLEX study will have completed at least one year of treatment and approximately 50% of patients will have completed two years of treatment. We believe at this timepoint, the data will have sufficient maturity to strengthen the prediction for long-term benefit. If the data meet these expectations, we anticipate submitting an NDA mid-next year for accelerated approval of sparsentan for FSGS in the U.S. In parallel, we'll be working on the combined IgA nephropathy and FSGS MAA application for conditional markering authorization of sparsentan and in Europe, with the expectation of a submission mid-next year as well. Both the PROTECT and the DUPLEX studies continue to advance and based upon the progression of these study date are well-positioned [indiscernible] near confirmatory endpoints in 2023. Lastly, on the pipeline, our optimism for the pegtibatinase programs remains high as it continues to advance through the Phase 1/2 COMPOSE study. COMPOSE is a dose escalation study, designed to assess the safety, tolerability, pharmacokinetics, pharmacodynamics, and clinical effects of pegtibatinase in patients with HCU. Patients in this study are being followed for up to 12 weeks in a blinded fashion in each cohort before entering an open label extension and we are anticipating a preliminary assessment from the study before year end. When we evaluate the preliminary data, we'll be examining a few factors. First, as you would expect with any early study of this nature is safety, we'll be looking for any signals of interest, including immune response. Next is early evidence of efficacy. We know that for those patients who are B6 non-responsive, treating physicians typically targeting patients below 100 micromolars of total homocysteine. If pegtibatinase to get patients below this level, we believe it could have the potential to become a clinically meaningful new treatment option. When we provide our update later this year, we'll look to provide insight into some of these areas of focus. I'll now turn the call over to Peter for the commercial update. Peter?

Thank you, Noah and good afternoon. We continue to be very pleased with our commercial organizations performance, especially in this environment where virtual ATP interactions remain commonplace and we still see that fewer patients are visiting their physicians compared to pre-pandemic times. In the third quarter, our execution resulted in 6% organic growth in net product sales over the same period last year. This was driven by underlying demand and strong patient compliance across all products. For our Thiola products, we continue to see new patients initiate treatments. And to-date, we have experienced limited impact from the generic version of the original formulation that entered the market in the prior quarter. Despite the limited impact so far, we do still anticipate an adverse impact on Thiola sales in the quarters ahead. Our focus will remain on identifying new patients, ensuring access to therapy and providing the important service and support that many patients needs to potentially be stone free. The bile asset portfolio also continue to perform in line with our expectations. As a result of the strong performance and commercial portfolio over the last two quarters, we anticipate ending the year with low to mid-single-digit growth in net product sales over 2020. Given the COVID 19 pandemic and evolving dynamics, this would be a meaningful achievement and further bolster the confidence in our team's abilities going into a critical period of anticipated launches for sparsentan. We are planning for launches of sparsentan in both IgA nephropathy and FSGS in the U.S. We anticipate the first launch to now be in IgA nephropathy and we have an incredibly exciting opportunity in front of us. In the U.S. alone, we believe there are between 30,000 and 50,000 patients living with IgA nephropathy that would be good candidates for sparsentan had launched if approved. And we believe that opportunity is likely to increase meaningfully over time with greater awareness and diagnosis. We are well-positioned to embark on our journey to reach these patients. We will be growing our organization from a position of strengths by scaling our proven infrastructure in net rare nephropathy to extend our core points and provide the services and support we know are critical for patients living with rare diseases. And in market research studies with nephrologists, prior to the PROTECT data readouts, we learned that sparsentan has an emerging product profile that rises to the top of the most desirable programs and development. Given the strength of the interim data from PROTECT and the positive feedback that we have received from the nephrology community since our topline announcement, we are confident that if approved, we will be in a strong position to ultimately establish sparsentan as the new treatment standard for IgA nephropathy. Overall, I have great confidence in our team's ability to add sparsentan to our multi-year track record of delivering life-changing therapies to people living with rare diseases. And I look forward to be sharing more about our progress as we continue to prepare the organization for potential upcoming launches. Let me now turn the call over to Laura for the financial update. Laura?

Thank you, Peter. For the third quarter of 2021, we reported net product sales of $54.2 million from our commercial portfolio compared to $51.1 million for the same period in 2020. We reported a GAAP net loss of $35.6 million for the third quarter of 2021. After adjusting for non-cash expenses and income tax, we reported a non-GAAP net loss of $7.9 million for the third quarter of 2021. On a GAAP basis, R&D expenses were $48.4 million for the third quarter of 2021. The increase compared to 2020 is largely attributable to increase patient involvement in the ongoing studies of sparsentan as well as advancement of the pegtibatinase program in HCU. On an adjusted basis, R&D expenses were $45.2 million for the third quarter of 2021. Relevant non-cash expenses for the third quarter included $3.2 million stock-based compensation and amortization. On a GAAP basis, selling, general, and administrative expenses for the third quarter were $36.1 million. The increase compared to 2020 is largely attributable to increased headcount attributable to the company's operations growth and professional fees. On an adjusted basis, SG&A expenses for the third quarter were $25.5 million. Significant non-cash adjustments for the quarter consisted of $10.6 million in stock-based compensation and depreciation and amortization. We ended the quarter in a strong financial position with $551.2 million in cash and cash equivalents. This balance includes the $55 million upfront payments we received as part of the joint collaboration licensing agreement with the Vifor Pharma that was entered into during the quarter. For the balance of this year, we expect modest increases in our operating expenses. As we look further out, we anticipate significant investments throughout next year as we prepare for multiple potential product launches, continued support the ongoing studies of sparsentan and advanced our pegtibatinase program. Taking into account the potential impact of generic Thiola, but not including additional business development, we anticipate this cash balance to support our planned operations into 2023. I'll now hand the call back over to Eric for his closing comments. Eric?

Thank you, Laura. I couldn't be more pleased with our organization's execution in the third quarter. We delivered impressive results from the pivotal Phase 3 PROTECT study. We made considerable regulatory progress across our sparsentan programs, entered into a collaboration agreement with a global leader in nephrology to maximize the value of sparsentan in Europe, Australia, and New Zealand, and we continue to effectively deliver our approved products to patients in need. With the regulatory pathways for IgA nephropathy and FSGS now set, we will be working in earnest to prepare three high quality NDA and MAA applications to be submitted next year. And we will continue our steps to prepare our organization to execute on successful launches of sparsentan if approved. Lastly, a few weeks ago, we announced the planned transition for Noah to an Executive Advisor role at the end of this year. I'd like to take this opportunity to thank him for all of his contributions in getting us to this strong position. We look forward to working closely with Noah to ensure a smooth transition in the coming months and his new role next year as we continue to advance our clinical studies and prepare our NDA and MAA applications. Thank you, Noah. Let me now turn the call over to Chris for Q&A. Chris?

Great. Thank you, Eric. Justin, can we go ahead and open up the line of Q&A please?

Thank you. [Operator Instructions] And our first question is going to come from Maury Raycroft from Jefferies. Your line is now open.

Hi everyone. Congrats on the update and happy birthday, Chris. My first question is if you can talk more about the IgA nephropathy pre-NDA meeting and say if it was the more mature eGFR data relative to FSGS that enabled FDA to concur that the interim analyses were adequate for submission? And can we assume that because of this IgA nephropathy regulatory update, that we can have more confidence that FSGS data will mature similarly?

Maury thanks so much for the questions. I'll turn that one over to Bill.

Yes, thanks. Thanks for the question Maury. The eGFR picture for the PROTECT study does represent a more mature dataset. That comes from a couple of things. Predominantly, the enrollment dynamics were very different. Recall that the PROTECT study began about six months behind the DUPLEX study. So, the work building the infrastructure was done on a DUPLEX study and the PROTECT study drafted in behind. So, with a linear -- much linear enrollment dynamics, we had a much greater fraction of the dataset that was out in the later timepoints. And that was in stark contrast to what we saw with the PROTECT study. To your other -- the other aspect of your question and confidence building for FSGS, I think that when we look across the program, sparsentan has been in three efficacy studies in two diseases and has performed very consistently across those studies. So, when you allow the picture to mature in DUPLEX, our expectation is that it's going to come in line and we'll meet our expectations. We'll have the data cut in the spring and that will give us that answer.

Great. I mean, maybe one follow-up. If you just remind what your expectations are for their review period for both programs for FSGS and IgA nephropathy?

So, for the PROTECT study, we will be requesting priority review. So, if we submit in the first quarter, then we -- if we are granted priority review, which we certainly believe this disease and this drug warranted with this dataset, that would mean we'd have an answer from the agency, a PDUFA date before the end of 2022. For FSGS, we expect to submit that in the middle of the year, next year following interaction with FDA on eGFR cut, and should those data's are filing, that would be a mid-year 2022 filing. So priority would put that in the first half of 2023. And if it's standard review, it would be early in the second half of 2022.

Great. Okay. Congrats again, and thanks for taking my questions.

Sure. Thank you.

Thank you Maury.

And thank you. And our next question comes from Greg Harrison from Bank of America. Your line is now open.

Good afternoon, guys. Thanks for taking our questions. First one is on pegtibatinase. What is the extent of the data that we could expect to see in the coming readout? And what would you consider it to be clinically meaningful there? And then assuming it is, what would be the next steps for this program if the data are supportive of moving forward?

Yes. So thanks so much Greg for the questions. I'll take the first one on what we can expect. And then I'll ask Bill to share a little bit more around the next steps. So as Noah mentioned, you were really looking at a couple of key areas with this analysis from the composed study. First and foremost, this is the first study in humans. So we want to have a particular eye on safety. The second aspect is to really understand the dose response in this trial, given that we are studying different dose cohorts. And then the third, and I think particularly around your question of what would be considered clinically meaningful, is to assess whether patients are able to get below 100 micromolars for total homocystinuria, and whether they're able to stay below those levels. That is considered the treatment goal in the guidelines and by clinicians and patients with homocystinuria. And so we're going to be particularly looking at that threshold. And what we'll obviously continue to assess that. But those are the major areas of focus as we go into that analysis. And I'll turn it over to Bill to talk about next steps.

Thanks, Eric. Yes, the first step will be to analyze the data from the interim analysis, and we expect to share that at least to some degree. The next immediate step is really to use that dataset and engage with regulators. And that'll be the results from the interim analysis of the COMPOSE study, as well as the current data from the Natural History Study. We'll then take their input and do our own feasibility analyses and work toward developing a plan for the next clinical study. In parallel to that we'll be working on manufacturing scale up and process development. The goals ultimately going to be to move downstream from the Compose study into a pivotal study. And that next phase of development, and we'll be able to share more about that once we've had those engagements with the agents.

Great. That's helpful. And then if I can sneak in one more. As far as the IgAN program, would you expect that there would be in an AdCom needed there?

No. One of the questions we asked in our pre-NDA interactions was their perspective on whether or not you will have an AdCom. The agency said that based on the data they've seen thus far, they don't anticipate calling for an Advisory Committee. We're not surprised with that given the data from the interim analysis, can we see that as a positive? That said, these things can change and we'll be prepared. Should an AdCom be called? But at this point, we don't expect to have.

Great. Very helpful. Thanks again, and congrats again on all the progress.

Thank you.

Thank you, Greg.

And thank you. And our next question comes from Joseph Schwartz from SVB Leerink. Your line is now open.

Hi. Thanks very much. I was wondering if you will be reporting any more data to investors at the time that you perform your next interim analysis of the DUPLEX study in the first half of 2022? Or will all of the information just be for the FDA? And likewise, will we hear whether the FDA has any feedback for the company on your plan to file as occurred when you perform your first interim analysis?

Joe, thanks so much for the questions. So as part of our interactions and plans for that additional eGFR cut, we're going to be working with the FDA on any disclosure plans. I would say, it's probably safe to assume that that we would not be providing any additional data given that it's the trial is ongoing. And we continue to be very focused on maintaining that blind and the trial integrity. Really, what we're going to be focusing on in large part is to communicate, following the meeting, once we receive minutes, or once we have submitted or accepted by FDA, the NDA. And so that really is going to be our focus as we look at those additional data. But as I've mentioned, we're going to be working with FDA to see what they are comfortable with us disclosing at that point.

Great. Thanks for the color. And then how would you rate the awareness and appreciation of proteinuria lowering is an important treatment goal in the community of physicians who see the most FSGS and IgA nephropathy patients? How ready is the market to adopt a proteinuria lowering agent likes sparsentan? And how much education do you still need to undertake in order to encourage strong uptake in the real world?

Yes. Thanks for that question. I'll have both Peter and Noah answer that. Given that Peter’s team is working very much on a lot of the market research with a broader nephrology community. Noah and his team with some of the top nephrologist, and they can provide a bit of feedback on what they are hearing. Peter, you want to start?

Yes. Thanks, Eric. And thanks Joe for questions. Well, what we have learned from the market research, as well as the thought leaders that we are speaking, which is proteinuria is often the market that results the treatment initiation and monitoring of patients how well they're doing, which they think makes sense because proteinuria is also the strongest predictor of progression of disease. So I think there is a well-established understanding of proteinuria and its relation to progression of disease in particular patients on higher risk towards dialysis. Noah, I don't know if you want to build upon that.

Yes. I think that's right, Peter. I think physicians and nephrologists specifically are acutely aware of the toxic effects of proteinuria. We speak of an AdWords all the time, and they're aware of the concern that proteinuria will drive worsening outcomes and ultimately case in dialysis, the need for immunosuppressive therapy. I think where the education comes in is, now that we have additional therapy and a potential therapy, it's around targets, educating around those targets, where they can realistically go, because it really had such limited options until now. Specifically in IgAN, for instance, your choices are very limited. ACEs, ARBs we know often fail and Immunosuppressants are very limited in that they can create concerns around their short-term treatments, and they often don't work. So I think awareness around sparsentan and the mechanism how it works, the safety data set it's really important that we get the message out there that realistically with the drug like sparsentan, there's a better chance of them achieving some of these targets that have been set out by the guidelines. So I think that that's certainly an area that we're focused on.

Sounds good. Thanks for taking my questions and best wishes to Noah.

Thanks Joe.

Thank you. And our next question comes from Michelle Gilson from Canaccord Genuity. Your line is now open.

Hi. Thank you for taking my question. I kept wondering if you could provide a little bit more color around your pre-NDA meeting. And what the FDA was most focused on? And I guess more specifically what eGFR analyses were done and presented to the agency for IgAN, and I know we discussed in the past that there are different ways that you can evaluate changes in eGFR slope. And I also I think that I heard you earlier allude to priority review timelines for IgAN. And I was just curious if that was discussed during your pre-NDA meeting?

Thanks, Michelle. Bill, would you like to take those questions?

Sure. I think I've got them all jotted down. As far as what was presented to the agency for the pre-NDA interactions. The briefing book presented a comprehensive summary of the interim analysis. So it was proteinuria measured multiple different ways or express different ways. eGFR versus time split by groups at a summary level, both observed and then the MMRM, which is the primary analysis endpoint. And additionally, some review of safety and adverse events. So that was how the analyses were presented. Your question around priority review, we certainly believe that this is an ideal case for priority review. But that's not something that gets granted at this stage of the game. We intend to request it. And we see this as an ideal case for it. But we won't know the answer to that question. Until after we've submitted the NDA in the first quarter.

Okay. And, one, if I can unpack that niche as well. You're evaluating different dose levels now. And you've indicated that you may evaluate another dose level. And I'm just curious if it's -- if you expect that you'll evaluate different dose intervals at another dose level, or if it's just, I guess, higher doses?

Yes. We have said that, within this study, we're looking both at dose regimen and dose levels. We will make the decision on what we're going to do with the next cohort when we see the data in December. So it could be either of those, or it could be staying at the same level of dose and increasing the amount of experience at the current level. So it's going to be a data driven decision, once we're on blinding at interim in later this year.

Okay. If I could just a follow-up, is there any I guess -- are there any issues with going up in volume here? I know, it is subcue dose -- if you do evaluate a higher dose?

So the there are limits to how much is tolerable on an individual subcue injection. As you increase in dose, depending on the solubility of the agent that you are working with. There can be limits there. It becomes a balance between patient need and what's patient what's acceptable with patients. But one of the easy ways to deal with that is to split the injection, if you are going to higher doses or higher volume into multiple subcue injections and that tends to ameliorate the issue.

Okay. Thank you guys so much for taking my questions.

Certainly, Michelle.

And thank you. And our next question comes from Liisa Bayko from Evercore ISI. Your lien is now open.

Hi. I guess congratulations are in order for both Chris and Noah. So congratulations to you both. And I've been fielding a lot of questions on HCU. And we've been doing a bunch of work on it. And I think the main question I'm getting is just like how much information investors are going to get when you do kind of preview some data. So can you maybe just elaborate too expectations are set appropriately for what kind of information you're going to get and how you know how much you can kind of like, communicate, what you're seeing in terms of response in patients?

Sure, I'll take that one Liisa. And, you know, our focus, again, is on those three areas of safety dose response and magnitude of effect on total homocysteine. There, of course, are other measures of efficacy that we're looking at, for example, assigning is a biomarker that is often assessed within HCU. So we're going to be looking at those aspects as well. I'd say the expectation is that, we want to make sure that we provide clarity on each of those questions, once we have that data read out. But we've not yet committed to whether how much data we're going to be disclosing at that time. Given that, one is a competitive space, and we want to make sure that we're not providing so much so as to lose the lead that we have in this space. But we also want to make sure that, we really have a good understanding of what that dose, that dose and dose regimen is, whether we believe that we have the right dose. We certainly wouldn't want to communicate efficacy, if we believe that there's something more that we could be pursuing. So that's a little bit of how we're thinking about it. We said that at a minimum will provide a qualitative update on each of those three questions, but we very well could be in a position to provide, more specific data. As we go forward.

And any kind of additional color on timing?

Well, we're on track to be able to provide that update sometime later this year. But to be able to narrow that down even further, I would say, we're just not at that point to do so. But we're very near.

Okay. And then just finally, on the same program, kind of want to look at it, I think it could be at least as big of an opportunity as far as Santen. And in terms of its value, because it has a pretty long like revenue tail, it actually could be pretty valuable as a, relative dispersant and more valuable actually. Can you maybe comment on how you're thinking about kind of the size of the opportunity and provide some benchmark?

Well, we certainly are excited about the opportunity, given that there's a high unmet need here. The addressable population, if we start there is 7,000 patients currently across the U.S. and Europe. But I think we recognize that, there are a few areas that really can be approved, which we believe is typically the case within rare disease. One is that, these patients are oftentimes undiagnosed, despite newborn screening, many of these patients still are not diagnosed early enough and go into adulthood before being effectively diagnosed, and while there are other therapies like high dose, Vitamin B6. The literature states that, there's a proportion of the 50% that are responsive, when we talk to experts in this area. They are very clear that is a very high estimate of the B6 responsiveness. So we think that there's still opportunity there to better understand, where the unmet need is, and who is above that key threshold. So that's going to be a big part of, of what we're doing in parallel to clinical development at this time. And, I'd say that, it's an enzyme replacement therapy. So, we'll continue to assess what the benchmarks are for pricing and what value we bring there. But we do believe that this is a significant opportunity for us. And, we are currently first in development, and we are really focused on ensuring that lead position.

Thank you very much.

Thanks, Liisa.

Thank you. And our next question comes from Carter Gould from Barclays. Your line is now open.

This is Justin on Carter. Thanks for taking the question and congrats on all the progress this quarter. Just one quick wrap-up on for us on tape to badness, understanding that, you don't want to be sort of too revealing on what data you expect to show on the reader. But Eric, you mentioned earlier, that duration of response is going to be sort of a key criteria in your moving forward decisions. And just wondering, if you can tell us how much duration data we should expect in this first readout? How much that's going to impact your next steps with the program and sort of, you know if you're going to be waiting on any more duration data going forward before you move out of the program.

Sure. Yes. I'll ask Bill to talk a little bit about what we're going to be looking at and what the trial design will allow in terms of follow-up.

Yes. So from a from a duration perspective, we'll have double blind data from everybody in the interim, up through 12 weeks, but then those patients go on to continue in open-label extension. So for many of the patients will have significantly longer windows of time for that. So as is often true and metabolic disease with biologic or biochemical endpoints, there's a degree of variability. That is certainly aided what you look with a longer window of ascertainment. So the trial designs very strong for that.

Awesome. Thank you very much.

Thanks, Justin.

Thank you. [Operator Instructions] Our next question comes from Tim Lugo from William Blair. Your line is now open.

Hey, guys, this is Watson [ph] on Tim. Thanks for taking the question. So I just wondering, Eric, if you could maybe provide a bit more color on the process behind choosing B4 partner Europe, what their infrastructure is? Why that makes them the ideal partner for you have them? And then as well, on the EMA application, have you discussed with the EMA the idea of submitting the combined applications? And what's the feedback on that? Thanks.

Okay, sure. So Watson [ph], thanks so much for the questions. I'll take the first one on really how our thinking evolved to select Vifor as our partner. And then I'll ask Bill to talk a little bit more about our engagements with the EMA. So as we set out to assess the value of partnering in Europe with sparsentan really it led us to think about who has an established presence within nephrology. And when we think about that it's not just having the relationships with nephrologist which Vifor clearly has, they have relationships not just with the majority of nephrology practices within Europe, but also with some of the top KOLs. They also have experience in working with regulators and with HTA bodies, not just nationally, but also regionally and in some countries at the hospital or local level, which countries like Spain is very important in ensuring optimal reimbursement and access. And that was very important when we thought about the launch of sparsentan. And then we thought about someone who's going to be a great partner for us, someone that's collaborative, and it's going to have the focus on making sparsentan the new treatment standard within Europe and I think we certainly found that Vifor had all of what we were looking for. And so, we felt like it was also the right time for us to make that decision, because there is quite a bit of work that needs to be done, not just to ensure filings from with regulators, but dossiers for HTAs and ensuring that we prepare the organization, the infrastructure and education. And so that's what led us to making that decision. And we think that we're in a really great place with Vifor. And I think what we have, as I alluded to in my prepared comments, is two organizations with exquisite focus in that same goal of making sparsentan the new kind of treatment foundation for IgA nephropathy and FSGS. And we think that that really does de risk the executional risk that comes with any launch. So hopefully that answers your question. And Bill, I'll turn it over to you on how we've discussed that combined file with the EMA.

Yes, certainly. Thanks for the question, Lachlan, we have discussed this with the EMA and they're aligned with our approach for the combined decision. We're working at the current time to schedule pre-MAA meeting to go through the interim analysis data and align on the content of the submission, but they are aware and align with the approach and so we're good to go there.

Thank you. And our next question comes from Laura Chico from Wedbush Securities. Your line is now open.

Thanks very much for taking the question. And I apologize if I had missed or drop off for a second. But I had a question just with regards to kind of contrasting the US versus the European regulatory strategies. So, if I'm understanding things correctly, IgAN could be submitted in the first quarter 2022, if successful with the additional data from DUPLEX, FSGS could be submitted in the middle of 2022. I thought I heard you say, though that there was an advantage to filing these submissions together in the European case. I'm just curious why it might not make sense to file these together in the US settings?

Sure. So I'll ask Bill to talk about that. And really, it's what both regulator -- regulatory agencies allow for pathways. And that's really what's driven, what ultimately is our strategy is how quickly can we get this out to as broad a population as possible, Bill?

Certainly, I mean, it's a logical question. From our standpoint, we have very strong interim trial results from PROTECT and a very clear pathway forward, that leads to a filing in the first quarter of 2022 IgA nephropathy in the U.S. We need to wait for the additional eGFR data, and then review that with the agency in order to support a similar filing for FSGS with the FDA, and what we don't want to do is wait that extra period of months and hold back the IgA nephropathy submission. In the U.S., we can submit in parallel or slightly offset and have basically cross reference between two active NDAs. Within the European system, there isn't a mechanism by which we can do that. So if we -- to optimize the strategy there by combining the two, IgA nephropathy and FSGS once the data are available, that allows us to get sparsentan to the most the largest number of patients, the quickest in that geography. If we didn't do it, that way, we have to wait for one review be completed before we can start the next or if we did parallel reviews, we'd end up with two different trainings, which isn't ideal either. So this is really two strategies with the same data that are optimized for the rules in their respective geographies.

Okay. That's helpful. And I can sneak in one quick follow-up. And again, I apologize if this has been asked. What is the risk to the US submission being delayed? IgAN submission to sync up with FSGS? Is there potential for the agency to kind of change their position or kind of tried to combine the reviews? Thank you.

Sure. Bill?

Yes, at this point, there's -- I don't see that happening. Early in development, we asked about combining the two indications into one and one IND, which will lead to one NDA, and they prefer to keep the two separate, two separate indications, two INDs, two NDAs. Part of that is driven by the fact that their metrics and how they are able to justify resourcing comes down to how many reviews they do, and how many NDAs. So, it doesn't help them in a fight for resources, if they reduce the number of NDAs artificially, but it also decouples them from a timing perspective. I don't see based on all the discussions that we've had with them, any indication that they would want to wait for subsequent data from the FSGS.

That's very helpful. Thank you.

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

Great, thank you, Justin. This concludes our third quarter update. Thank you all for joining us this afternoon to talk about our progress. We look forward to updating you further throughout the balance of the year. And I hope you all have a great evening.

Thank you. This concludes today's conference call. Thank you for participating You may now disconnect.