Good morning, and welcome to the Mirum Pharmaceuticals business update call. My name is Hillary, and I will be your operator today. All lines are currently in a listen-only mode, and there will be an opportunity for Q&A after management's prepared remarks. I would now like to hand the conference over to Andrew McKibben, SVP of Strategic Finance and Investor Relations. Andrew, please go ahead.
Thank you, Hillary, and good morning, everyone. I'd like to welcome you to Mirum's conference call to discuss top-line results from the phase III portion of the AZURE-1 study of brelovitug in chronic hepatitis delta, along with 48-week data from the phase II-B portion of the study. For our prepared remarks, I'm joined today by our Chief Executive Officer, Chris Peetz, our Executive Vice President of Clinical Development, Nancy Shulman, and Peter Radovich, our President and Chief Operating Officer. Also joining us for the Q&A portion of the call are Rob Myers, our Chief Medical Officer, and Eric Bjerkholt, our Chief Financial Officer. Earlier today, Mirum issued a press release announcing these results. A copy of that release and our SEC filing, along with a presentation summarizing the data, are available on the investors section of our website.
Before we start, I'd like to remind you that during the course of this conference call, we will be making certain forward-looking statements based on management's current expectations, including statements regarding Mirum's programs and market opportunities for its approved medicines and product candidates, and financial guidance. These statements represent our judgment and knowledge of events as of today and inherently involve risks and uncertainties that may cause actual results to differ materially from the results discussed. We are under no duty to update these statements. Please refer to the risk factors in our latest Form 10-Q and subsequent SEC filings for more information about these risks and uncertainties. With that, I'd like to turn the call over to Chris. Chris?
Thanks, Andrew, and thanks for joining our call this morning. Today marks another defining moment for Mirum and, more importantly, for patients with hepatitis delta. We are excited to announce that the phase III portion of the AZURE-1 study demonstrated rapid, statistically significant, and clinically meaningful improvement on the primary endpoint with brelovitug. To put these results in context, hepatitis delta is the most severe form of viral hepatitis, with the potential for rapid progression to cirrhosis, liver cancer, and liver-related death. In AZURE-1, brelovitug treatment at 24 weeks led to virologic response and ALT normalization in the majority of patients. These results represent the first pivotal phase III readout of the AZURE program, and they position brelovitug as a well-tolerated, single-agent, fully human monoclonal antibody with potential to treat a wide range of hepatitis delta patients.
We continue to expect top-line results of the phase III AZURE-4 study in the fourth quarter, keeping us on track for a planned BLA submission in the first half of next year. This news comes just days after another important milestone for the company announced last Friday. The FDA approved Atebrioz tablets to reduce the volume of total new heterotopic ossification in adult and pediatric patients aged 12 years and older with fibrodysplasia ossificans progressiva, or FOP. Atebrioz is now the fourth commercial medicine at Mirum. We brought Atebrioz into the rare genetic disease portfolio only in the second quarter this year, so this is fast progress and credit to the Incyte team who did a fantastic job leading this through regulatory review. For today's updates, Nancy Shulman, EVP of Clinical Development, who designed and leads the AZURE program, will walk through the results.
Peter will also provide comments on launch preparations for brelovitug and the newly approved Atebrioz. I am happy to welcome Dr. Rob Myers, who joined us last week as our Chief Medical Officer for the Q&A portion of the call. Rob is a widely recognized hepatologist and physician scientist with more than two decades of experience developing novel medicines. He joins us from OrsoBio, where he was Chief Medical Officer and Head of Development, and before that, he spent a number of years at Gilead. He joins us at a busy time for our pipeline as we look to transition three programs from clinic to commercial in the near term. Finally, before diving in, I would like to say thank you to the patients, investigators, and study team around the world who made AZURE-1 possible. Now, over to Nancy. Nancy?
Thank you, Chris. I am very pleased to review the top-line results from the phase III portion of the AZURE-1 study, and I will also walk through the top-line 48-week results for the phase II-B portion of the study. Like Chris, I would like to extend my gratitude to all the participants, investigators, and the dedicated Mirum study team who made this possible. As a reminder, hepatitis delta occurs only in the setting of hepatitis B virus co-infection because the hepatitis delta virus relies on hepatitis B's surface antigen for viral assembly, entry, and dissemination. Hepatitis delta is the most severe form of viral hepatitis, and relative to chronic hepatitis B alone, delta is associated with the more severe liver disease and more rapid progression to cirrhosis, liver cancer, and liver failure. Brelovitug is a fully human monoclonal antibody that binds hepatitis B surface antigen.
It works by clearing hepatitis delta from the circulation and by preventing entry into liver cells. Before getting into the data, it is worth discussing the combined approvable endpoint recommended by the FDA, which includes both virologic response and ALT normalization. HDV RNA measures the degree of viral suppression, while ALT reflects ongoing liver inflammation. Both are important. Although viral suppression generally leads to reductions in inflammation, a virologic response alone does not necessarily mean that liver inflammation has resolved. Liver inflammation is the key driver for progression to fibrosis, cirrhosis, and liver cancer. In this setting, ALT is the most practical and widely accepted biomarker for assessing inflammatory activity within the liver. Now turning to the phase III results. The phase III portion of AZURE-1 enrolled 153 patients globally, randomized approximately two-to-two-to-one to receive brelovitug 300 mg once weekly, self-administered by subcutaneous injection at home.
Brelovitug 900 mg once every four weeks, administered in clinic by subcutaneous injection with an additional loading dose at week two, or third arm was delayed treatment starting with a crossover at week 24, to the 300 mg once weekly regimen. We enrolled a broad patient population with meaningful disease burden.
There was no upper limit on ALT for study participation, and at baseline, we had 18% who had ALT above 5 x the upper limit of normal. 41% had cirrhosis, and 20% had clinically significant portal hypertension. I am very pleased to say that at week 24, brelovitug met the primary endpoint. I am going to focus on the results for the 300 mg once weekly dose, but the numbers are highly significant for both arms. For the 300 mg dose arm, 56% achieved the combined endpoint compared to zero in the delayed treatment arm with a highly significant P value.
Virologic response was achieved in 86% compared to zero in the delayed treatment arm. HDV RNA below the limit of quantification with our assay, this is 10 IU/mL, was achieved in 25% compared with zero in the delayed treatment. This includes 17% who were at target not detected. ALT normalization was achieved in 63% of patients compared to zero in the delayed treatment arm. Brelovitug was well-tolerated with a safety profile consistent with the previously reported AZURE-1 phase II-B results. There were no treatment-related serious or Grade three adverse events or discontinuations and low rates of flu-like symptoms. Now turning over to the 48-week data from the phase II-B portion of AZURE-1. As a reminder, the phase II-B portion included the first 53 patients enrolled in the study. At EASL earlier this year, we presented the full week 24 results.
Here we provide an update out to week 48, which showed continued deepening of viral suppression and increasing rates of ALT normalization with ongoing treatment. A highlight is the proportion achieving HDV RNA below the lower limit of quantification, which again is 10 IU/mL. Remember, the average HDV RNA levels for these patients at baseline was around a 500,000 . So, dropping these to less than 10 is a significant reduction. Finally, we also expect to present two-year data from our original phase II study showing continued improvements in ALT and HDV RNA in the cirrhotic patients at an upcoming medical conference. Overall, these results reinforce the compelling profile for brelovitug as a well-tolerated, convenient, single-agent potential therapy for patients with hepatitis delta, including those with advanced disease. With that, I will turn it over to Peter.
Thanks, Nancy. Hepatitis delta is a natural extension of our rare disease commercialization strategy. Bringing life-changing medicines to underserved and underdiagnosed patients is where Mirum excels, and brelovitug fits that profile. Let me start with the opportunity. We believe there are approximately 15,000 patients with hepatitis delta in the United States. who are diagnosed, insured, and under care today. Over the course of 2026, Mirum has supported several hepatitis delta disease awareness initiatives and engaged with hepatitis B providers from a broad array of clinical settings to better understand the delta diagnosis paradigm and disease burden. Through our disease state conversations, it is clear to us that delta testing in the United States. has been extremely low and that most of the burden exists in non-academic community settings. Thus, we believe the true U.S. prevalence is considerably larger, with the significant majority of patients undiagnosed today.
Given our confidence in brelovitug's robust single-agent profile shared today by Nancy, we are updating our peak sales guidance to at least $1 billion. We believe one of the strengths of the Mirum model is the efficiency of our commercial organization. Today, our rare liver team supports LIVMARLI in pediatric and adult liver care settings. Over time, we expect to leverage this capability utilizing the same team to support three commercial medicines, LIVMARLI, volixibat, and brelovitug. Turning briefly to Atebrioz. Atebrioz is a once-daily oral ALK2 inhibitor designed to target the disease-driving pathway at the center of FOP biology. As Chris mentioned, we received FDA approval late last week, and our rare genetic medicines team is ready to go. We are excited about the label and believe it can facilitate broad access for FOP patients aged 12 and over.
With product launch in October, we expect revenue to begin in the first quarter of 2027. This launch leverages the Mirum rare genetics team already in place supporting CTEXLI and CHOLBAM, as the physicians who care for FOP patients are concentrated in many of the same specialized centers. Most importantly, we are both grateful and enthusiastic about the opportunity to bring another high-impact medicine to a rare disease patient population in desperate need of treatment options. With that, I will turn it back to Chris. Chris?
A reminder to unmute yourself locally.
Maybe we will have Eric wrap up.
Yes. Chris seems to be muted, so I will read the last section before we open it up for Q&A. Thanks, Peter. Today's updates are exciting for both patients and Mirum. I am proud that we have built an industry-leading team in rare disease to deliver moments like this with a new approved therapy for FOP patients and strong phase III results in hepatitis delta, and our strategy is positioned for continued growth. Today, fewer than 5% of rare diseases have an approved treatment, and even where treatments exist, significant unmet need remains. The upcoming launch of Atebrioz is an immediate opportunity to put our business model to work to help patients with FOP. For hepatitis delta, these are the first pivotal phase III results from the AZURE program.
The Week 24 results reinforce our excitement about what brelovitug can mean for patients with hepatitis delta as a highly active, well-tolerated potential medicine for a deadly disease. Looking ahead, we expect top-line data from AZURE-4, a second phase III study with a similar design to AZURE-1, in the fourth quarter, which keeps us on track for a BLA submission in the first half of next year. Once again, thank you to the patients and investigators who participated in AZURE-1, and a huge thank you to the Mirum team, who are working relentlessly to bring these important medicines forward. With that, operator, please open the line for questions.
We will now begin the question and answer session. Please limit yourself to one question and one follow-up. If you would like to ask a question, please press star 1 to raise your hand. To withdraw your question, please press star 1 again. We ask that you pick up your handset when asking a question to allow for optimum sound quality. If you are muted locally, please remember to unmute your device. Please stand by while we compile the Q&A roster. Your first question comes from the line from Yigal Nochomovitz from Citigroup. Your line is open. Please proceed with your question.
Hi. Great. Thank you very much, and congratulations on both the approval as well as the data this morning. I was just curious if you could speak a little bit with regard to the read-through to AZURE-4. Obviously, the endpoint there is a little bit more stringent. Could you just comment on how you see that playing out, given the results in AZURE-1 with obviously very strong 86% virologic response, although a lower TND rate of 17% at Week 24? Then just related to that, in terms of the filing, what is the latest commentary from the FDA with respect to needing both AZURE-1 and AZURE-4? Is there a pathway where, if it is just AZURE-1 for whatever reason, you would still be in good position to file? Thank you.
Yeah, thanks for the question.
Yeah, thank you.
A couple of quick comments, and I will pass it over to Nancy Shulman to speak about the difference in study design into AZURE-4. The one thing I would say is overall, we are aligned with FDA on the AZURE-1 and four being part of the filing, and AZURE-4 is just around the corner. We expect to be bringing those results in the fourth quarter, and on track for that first half BLA submission. Nancy, get into some of the details on AZURE-4.
Yeah. Thanks, Chris. The endpoints are quite similar. AZURE-4 is a 24-week endpoint for the brelovitug. It is the comparison. We are comparing 24 weeks to 12 weeks. As we see here, the control arm doesn't really improve from 12- 24.
Okay. Thank you.
Thanks for the question.
Your next question comes from the line of Ryan Deschner from Raymond James. Your line is open. Please go ahead.
Good morning, and congratulations on the strong readout. Are you seeing continued improvement in ALT and ALT normalization at time points later than the 48 weeks in the phase II-B portion of AZURE-1? And I have a follow-up.
Yeah. Just to put a couple things in context, and I'll let Nancy speak again to the data. Here, we're providing the phase III update. That's a 24-week endpoint. The long-term follow-up from the phase II-B at Week 48.
And we have additional analyses out to two years planned from the phase II-A, so painting a nice picture overall, but I'll let Nancy speak to some of the trends that we're seeing.
The short answer to your question is yes, we do see continued reductions in ALT even when they're below the upper limit of normal.
Got it. Thank you. Can you attribute the lack of mean reversion on the primary endpoint or ALT normalization particular to in this readout compared to the phase II-B portion of AZURE-1?
Yeah, that's a great question. Remember, there's approximately 20 patients in each of the brelovitug arms in the 2b. Remember, these are point estimates, and they have confidence intervals around them. If you look at the confidence intervals, they still overlap. We think they're not really different.
Got it. Thank you very much.
Thanks for the question.
Your next question comes from the line of Josh Schimmer from Cantor Fitzgerald. Your line is open. Please go ahead.
Hey, thanks for taking the question. Congrats on the results. I guess considering the community setting for HBV patients, how might that impact your overall commercial strategy, if at all? Maybe you can elaborate on some of the efforts you are planning to undertake to continue to identify new HBV patients. Thank you.
Yeah, thanks for the question. Pretty active on this front. I will let Peter share what we have been up to.
Yeah, thanks for the question, Josh. Indeed, many of the HBV patients and therefore delta patients are not in gastroenterology hepatology. Many of them are in infectious disease or even primary care settings and select areas, often in urban areas where immigrant populations reside. We do actually have a team out in the field now doing disease state awareness, scientific exchange. Ten or so folks out there now interacting with those people, raising awareness of the disease and testing paradigms and hopefully eventually new therapies.
And can-
Was there a follow-up, Josh?
It seems that that analyst has dropped, so I will allow them to rejoin the queue in case there is a follow-up. We will move on to the next question, which is from James Condulis from Stifel. Your line is open. Please go ahead.
Hey, thanks for taking my question, and congrats on all the updates. Just a quick one. As it relates to efficacy and what you think matters most to docs in the real world, just curious, is it the composite virologic response, certain measures of virologic response? Just curious what you hear from docs, and then on that point as it relates to the commercial opportunity and the new estimate, can you just expand on what is driving that? Thanks so much.
Thanks for the question.
Yeah, great question.
Ask Nancy and Rob to comment on the first portion and pass over to Peter for the commercial comment.
Yeah. To answer your question, I am an infectious disease person. Rob is a hepatologist, so he can opine as well. Both ALT and HDV RNA responses are important. One of the things that I will say is that there has been no actual data that shows the predictability of the degree of suppression and how that relates to clinical outcomes. If you get to, say, 100 IU/mL or you get to LOQ or you get to TND, there has been no data in hepatitis delta suggesting that one predicts better outcomes than the other. We know that in hepatitis B, actually ALT normalization predicts endpoints such as liver cancer and progression to decompensation more so than the degree of suppression, particularly TND versus other. I think both of them are important, especially in therapies that are going to require longer term.
Yeah, I agree 100% with Nancy. I think seeing profound viral suppression and ALT normalization in tandem are important. We know that it is liver inflammation and liver cell injury which drives fibrosis and the complications of hepatitis delta. So the biochemical responses we are seeing are very encouraging. I will also say we are seeing reductions in liver stiffness, which seem to increase over time which portend well for prognosis of these patients and looking forward to presenting these data at an upcoming conference.
James, on the commercial aspect of the peak revenue update of your question, yeah, the primary driver of that is this robust single-agent activity data that Nancy reviewed today. I feel really good about the profile and continued confidence as the primary driver of that. Also would note that recent entrant in the U.S. of Hepcludex pricing at about $285,000 WAC per patient per year came in a bit above the price levels we had assumed in the prior forecast we had communicated at the time of the Bluej ay transaction.
Makes sense. Thanks so much.
Thanks for the question.
Your next question comes from the line of Brian Skorney from Baird. Your line is open. Please go ahead.
Hey, good morning, guys. Congrats on two positive wins over the weekend. Just two quick ones from me. Just in terms of the 300 mg dose itself, can you just relay what the minimal volume that dose fits into and thoughts on a single auto-injector? Just on competitive labeling, ultimately, bulevirtide has a box warning about severe hepatitis flares upon cessation of therapy. Maybe in the current dynamic, it's kind of a good thing to have on label as it emphasizes compliance. But just thinking of a competitive landscape, is the assumption that all of these would have on-label warnings about hepatitis flares on stopping therapy, or is there any data to indicate that you would potentially get around that somehow?
Hey, Brian. Thanks for the question. I think from the starting point, it's probably too early to speak to label on this and making some of those comparisons. But I'll pass it over to Nancy to talk a little bit about administration of the 300 and the overall profile.
Yeah. Thanks, Chris. The volume of the 300 mg is 2 mL, and it doesn't require reconstitution. The answer is, we are working towards an auto-injector or prefilled syringe, and I can hand it over to Peter.
Sure. Yeah, Brian. The presentation at launch, as Nancy mentioned, liquid in vial, no reconstitution required, but we are working on an auto-injector that we hope to introduce in the life cycle.
Great. Thank you. Gotcha.
Just kind of putting this all together for the profile for brelovitug, that simple once-weekly administration with a single injection really is a convenient option for patients, especially when you put it in the context of not needing to have a cut-off for baseline ALT or liver stiffness or some of the things that are top of mind for care of these patients. Yeah, thanks for the question. We can move on to the next one, operator.
Thank you so much. Your follow-up question is from Kalpit Patel from Wolfe Research. Your line is open. Please go ahead.
Yeah. Hey, good morning, and thanks for taking the question. So in your phase II and phase III studies, you allowed patients with ALT greater than 5 x the upper limit of normal, whereas it looks like Vir is excluding them. Did those patients respond differently on any of the efficacy endpoints, either things like ALT normalization or TND or any virologic measures? If you exclude that subgroup, does the efficacy get better on any of those?
That's a great question. The actual statistical comparisons between those who have a higher ALT at baseline versus those who don't, the subgroups are not large enough to show statistical significance. There's a trend, though, that if they're higher at baseline, it takes a little longer to get there.
Okay. Got it. If I can squeeze in a quick follow-up here, where do you guys see the ultimate differentiation against Vir's combo? Would you consider adding a second mechanism over time to drive perhaps deeper viral suppression and potentially exceed their TND rates?
I think overall, just the profile for brelovitug looks very compelling here. It's very well-tolerated, minimal adverse events from the flu-like symptoms and injection site reactions, and drives over time a deepening of response with a simple, fully human monoclonal antibody. We think it's going to be a very competitive profile at launch.
Thank you for your question. Your next question comes from the line of Joseph Thome from TD Cowen. Your line is open. Please go ahead.
Hi there. Good morning. Congrats on the update, and thank you for taking my questions. Maybe one on the data. Obviously, seeing good overall responses, but is there anything in a patient's profile, maybe in the patients that did have a larger response that is predictive there, either in terms of disease progression or anything like that would predict a non-response at this point? Second, on the commercial finding patients, when you mentioned the community setting, can you talk a little bit about are these patients actively seen by physicians? Or how much of a lift is it going to be to market the drug and kind of get patients to their doctors for a diagnosis? Thank you very much.
Thanks for the question, and split this one up between Nancy and Peter.
Yeah. Thanks for the question. As far as your question on non-response, we actually didn't have anybody that didn't have a response, and those who were not responders at week 24 are declining and actually responding, hitting that two-log threshold at a subsequent time point. It's hard to do baseline predictors when everybody responds.
Yeah, Joseph, your question on the patient finding side, it's actually pretty tractable. These patients are being managed for their hepatitis B. We can see both in medical claims and pharmacy claims. They're on NUCs, obviously, where they're being managed and target those physicians. I think the key point we're trying to make is they're just not in academic settings by and large, right? So, you think about large hepatology, liver transplant settings, that's not where the vast majority of the burden is. But it is a tractable group, largely concentrated in the major urban areas in the United States. and something that we don't think will take a substantial investment and that we can largely leverage a lot of what we have here at Mirum already.
Your next question comes from the line of Gavin Clark-Gartner from Evercore ISI. Your line is open. Please go ahead.
Hey, this is Yesha on for Gavin. We were just wondering how you're thinking about filing in terms of dose. Is the base case both doses, or are you planning to move forward with one? Thank you.
Yeah, thanks for the question. I believe the go-forward dose, but keep in mind that we're still waiting for confirmation of that and the AZURE-4 results in Q4. But all on track for first half submission.
Your next question comes from the line.
Your next question comes from the line of Jessica Fye from JPMorgan. Your line is open. Please go ahead.
Hey, guys. Good morning. Thanks for taking my question. I was curious, when you talk about the billion-dollar peak for brelovitug, can that be achieved within the existing diagnosed patient population? If not, how much patient identification and diagnosis would you see being needed to get there? Thank you.
Thanks, Jess. We believe it can be achieved in the existing diagnosed population. I think you can get a lot of the way there just in the U.S. Of course, there's a substantial international opportunity that we'd leverage our international team to launch this product as well. I think there will also be a lot more interest in testing in the future and even now that there's an FDA-approved medicine. So I think we'll see the overall number of diagnosed patients increase, but for our revenue guidance, that's really an upside for us.
Great. Thank you.
Your next question comes from the line of Mike Ulz from Morgan Stanley. Your line is open. Please go ahead.
Good morning. It's Avi Novick on the line for Mike. Thank you for taking our questions. I guess, appreciating that the phase II-B data on cirrhotic patients you'll be stating for a medical conference, maybe could you speak to the phase III population overall and how cirrhotic versus non-cirrhotic patients responded? On a related note, I guess at what point in disease progression are most patients currently being diagnosed today? Are they generally more advanced and have cirrhosis, or are they perhaps earlier on? Lastly, appreciating a 24-week study is not enough time to collect outcomes data. In your longer-term extensions, are you maybe looking at whether cirrhosis can be prevented or reversed potentially in your longer-term studies? Thanks.
Thanks for the questions. The first question, is there any difference in response between cirrhotics and non-cirrhotics? The answer to that question is no, there's no apparent difference between the two. I think the second question was about when are people diagnosed. In general, patients with HDV, because of the speed of progression, they tend to be more advanced upon presentation, at least currently, than patients like with hepatitis B. Historically, in these studies, the rate of cirrhosis usually is between 30% and 50%. If that gives any idea. The last question about, are we studying clinical outcomes? The answer to that question is yes. The AZURE studies will look at 96 weeks of treatment, then subsequently we'll have the option to roll over to an open label extension for an additional up three years of treatment.
There, we will look at the rates of disease progression over the course of five years then compare those to a historic control.
Your next question comes from the line of Lisa Walter from RBC Capital Markets. Your line is open. Please go ahead.
Oh, good morning, and thanks for taking our question and for the presentation this morning. Maybe from a modeling point of view, should we assume patients will be under treatment with brelovitug lifelong, or is there the possibility that some patients could stop treatment after being maintained with the viral load below the lower limit of quantification for some time, similar to what's going on in hepatitis B? Any color here would be helpful. Thanks so much.
Yeah, thanks for the question. We are assuming this is chronic therapy and so the protocols are being conducted as well.
Your next question comes from the line of Jon Wolleben from Citizens. Your line is open. Please go ahead.
Thanks for taking the question and congrats on the data. Wondering how you are thinking about long-term follow-up in the phase III population, given the similar phase II-B 48-week response rates. You guys said they seem to be overlapping. How important is it for docs to see continued benefit over time for chronic use? Do you think these 24 weeks' data is enough to warrant adoption early on?
Hey, Jon. Thanks for the question. I think what we are seeing here over time is really encouraging for what prescribers hopefully would be able to expect once this gets out in broader use. They see continued improvement across all measures over time. Maybe pass it over to Nancy to reiterate what we are seeing at week 48 and even two-year time points.
Yeah. Again, we see increasing rates of both ALT normalization and HDV RNA suppression with the deepening of the HDV RNA suppression over time, as I presented in the 012b. We also, remember, presented data on our phase II-A, and you see the exact same thing there. So at 24 weeks is better than 40 or 48 weeks, you get better responses than 24 weeks. And again, I am not going to say any kind of data, but we hope to present the two-year data at upcoming conference.
Thanks, guys.
Thanks for the question.
Your next question comes from Swayamp akula Ramakanth from H.C. Wainwright. Your line is open. Please go ahead.
Thank you. This is RK from H.C. Wainwright. Congratulations on the data and the approval. A quick question from me. What evidence do you believe is required before you can call brelovitug differentiated from entry inhibition or combination regimens, especially on TND and off-treatment durability? Also, will you be reporting the HBV background therapy and also the antigen kinetics when you present the full data?
Thanks, RK, for the question. The last component of it, we will work to get these data presented and a publication strategy to get a lot of that detail out over time. In terms of the differentiation, we see it all there. With a single agent that is well-tolerated, simple one injection administration once weekly to drive this kind of response that only deepens over time, we think this meets the treatment objectives for most physicians treating hepatitis delta. So quite excited about what this profile means and how differentiated it will be when we get it out in market.
Thanks. Thank you for taking my question.
Thanks for your question.
Your next question comes from the line of Joe Schwartz from Leerink Partners. Your line is open. Please go ahead.
Hi. Congrats on all the recent progress. Can you talk some more about what specifically were needed to close the gap between the 15,000 diagnosed and 40,000 prevalent HDV patients in the U.S.? How much of this depends on things like guideline changes, reflex testing, EMR prompts, or other factors, and what's the likely timeline for certain drivers? I heard you acknowledge that HDV testing is currently extremely low, but you're raising your peak sales expectation, and you alluded to some initiatives which you've been exploring. I was wondering, what have you learned from these initiatives which points to a higher TAM?
Yeah. Thanks for the question, Joe. I think the points you make, EMR prompts, reflex testing, guideline changes, those are all important. I'll say, though, I think one of the things that strikes me the most from all the conversations we've been having at Mirum with HDV clinicians over the last year in the U.S. as to the reason why the testing is extremely low, is that there's just been no available therapies. The conversation is frequently, "Yeah, we could talk about EMR prompts. We could talk about reflex testing, but why?
Why do I want to give someone a diagnosis for the most deadly form of viral hepatitis if I don't have a therapy to offer them?" My editorial view is, I think certainly with the FDA approval of Hepcludex, we're going to see that change, and hopefully with more approvals coming in the future, we'll see a lot more interest from clinicians for that baseline interest to actually do the testing. In terms of the how, I think that the how is exactly what you described, getting on guidelines, EMR prompts, et cetera. You asked about our peak sales guidance. Our change there was primarily around the confidence in the product profile that from the data that Nancy presented, the robust single-agent activity, that you see improve over time. That's really the primary driver for us increasing that.
Also mentioned in response to our previous question that our assumed price has gone up a little bit from what we communicated at the time of the Blue Jay transaction based on how Hepcludex price landed with the Gilead launch. That any increase in the number of diagnosed patients under management, which is currently about 15,000 in the U.S., that would be upside. That is not baked into our base case thinking.
Helpful. Thank you.
Your next question comes from the line of Ryan Deschner from Raymond James. Pardon me, your line is open. Please go ahead.
Thank you very much. Quick follow-up. What can you tell us about your updated expectations on Atebrioz pricing in particular, given where Regeneron has priced their drugs? Thanks.
Yep. Thanks, Ryan. We communicated with the press release on Friday. We will launch in October. Plan to make a final decision on price with launch. But yeah, just for general guidance, I would expect it to be in the corridor of where Pasatru priced.
Thank you very much.
There are no further questions at this time. I would now like to turn the call back to Chris Peetz, CEO, for closing remarks.
Okay. Well, thanks everyone for joining the call today. Obviously a very exciting moment for Mirum, and more to come in the fourth quarter. Have a great day.
This concludes today's call. Thank you for attending. You may now disconnect.