Mirum Pharmaceuticals, Inc. (MIRM)
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May 8, 2026, 9:49 AM EDT - Market open
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Earnings Call: Q1 2026

May 6, 2026

Operator

Good afternoon, and welcome to Mirum Pharmaceuticals' first quarter 2026 earnings conference call. My name is Tracy, 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. If you would like to ask a question during that time, press star one to raise your hand. I would now like to hand the conference over to Andrew McKibben, SVP of Strategic Finance and Investor Relations. Please go ahead.

Andrew McKibben
SVP of Strategic Finance and Investor Relations, Mirum Pharmaceuticals

Thank you, Tracy, and good afternoon, everyone. I'd like to welcome you to Mirum Pharmaceuticals' first quarter 2026 earnings conference call. For our prepared remarks, I'm joined today by our Chief Executive Officer, Chris Peetz, our President and Chief Operating Officer, Peter Radovich, and Eric Bjerkholt, our Chief Financial Officer. Our Chief Medical Officer, Joanne Quan, will be joining us for Q&A. Earlier this afternoon, Mirum issued a press release reporting our first quarter 2026 financial results. Copies of the press release and our SEC filings are available in the Investors section of our website. Before we start, I'd like to remind you that during the course of this conference call, we'll 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 said, I'd like to turn the call over to Chris. Chris?

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks, Andrew. Good afternoon, everyone. We have a number of important updates to cover today. I'd like to start by grounding in the vision we set when we founded Mirum in 2018, building a company focused on bringing forward medicines for overlooked rare diseases. This quarter reflects the progress we've made in turning that vision into a durable, growing business. Our start was based on LIVMARLI. Today we are a broader rare disease company with 3 approved medicines and a pipeline positioned to deliver multiple new therapies over the next 2 years. These high-impact programs are grouped across 2 focus areas: rare liver disease, where we have built clear leadership, and rare genetic disease, where we are establishing a second growth platform, each with distinct commercial capabilities. Across both, we've built a financially self-sustaining business that can support continued investment in the portfolio.

Our strategy is driving compelling results. Starting with rare liver disease, uptake of LIVMARLI remains strong, driven in part by performance in PFIC, which continues to exceed expectations. Based on that demand and continued performance across all brands, we are raising our full-year revenue guidance to $660 million-$680 million. More importantly, we are now seeing the next phase of our rare liver disease business take shape. Our recent clinical readouts in PSC and hepatitis delta represent important potential expansions for this business, extending beyond our pediatric foundation into larger patient populations with significant unmet need. In PSC, the VISTAS study of volixibat showed a significant improvement in pruritus, reinforcing the potential for volixibat to play an important role for these patients who currently have no approved medicines.

This is a major advance in PSC research and positions volixibat as a potential first approved medicine for patients in the U.S. In hepatitis delta, results from the phase II-B portion of the AZURE-1 study further support the potential for brelovitug in a patient population where treatment options are extremely limited. We look forward to the upcoming late-breaking presentations for both VISTAS and AZURE at EASL later this month. In parallel to this expansion of our rare liver disease business, today we are announcing another step in building out our rare genetic disease business with the addition of zolegorsertib, recently licensed from Incyte. Zolegorsertib is a once-daily oral ALK2 inhibitor in development for fibrodysplasia ossificans progressiva, or FOP, an ultra-rare progressive condition where patients develop bone in soft tissues.

This accumulation of excess bone leads to profound physical immobilization, with most FOP patients becoming wheelchair dependent by early adulthood and severely impacts life expectancy. Based on the strength of zolegorsertib's PROGRESS study conducted by Incyte, an NDA has been accepted with priority review with a PDUFA date of September 26th this year. If approved, we expect to launch by year-end. This is a strong strategic fit aligning with our capabilities in rare genetic disease, where care is concentrated in a small number of specialized centers and requires deep engagement with patients, caregivers, and physicians. Stepping back, we've built a company with multiple commercial growth drivers, a pipeline of meaningful upcoming catalysts, and the financial strength to advance our portfolio independently. This foundation is translating directly into high-impact medicines for patients and into value creation as we deliver on our strategy.

With that, I'll turn the call over to Peter to walk through the commercial portfolio in preparation for these 3 upcoming potential launches. Peter?

Peter Radovich
President and COO, Mirum Pharmaceuticals

Thank you, Chris. The first quarter was another period of strong commercial execution, with total net product sales of approximately $160 million. This included LIVMARLI net product sales of $84 million in the U.S. and $30 million internationally, with the bile acid medicines contributing $46 million. Robust adoption in PFIC, particularly in adult patients, continues to be a strong point for LIVMARLI, as education to increase awareness and recognition of genetic cholestasis among adult liver providers continues to be successful. Additionally, we saw stronger than expected performance in Q1 international LIVMARLI sales, as well as continued new patient adds in Alagille worldwide.

The bile acid medicines grew in a manner consistent with their cadence over the last several quarters, highlighted by our rare genetics team continuing to identify undiagnosed patients with CTX. Overall, we expect these dynamics to continue and as a result, are raising our full year 2026 net product sales guidance to $660 million-$680 million. As Chris mentioned, we are also beginning to see the next phase of growth in our rare liver disease business take shape. The recent results from the VISTAS study of volixibat and PSC and the AZURE-1 study of brelovitug and hepatitis delta represent important steps in extending our presence into larger, primarily adult liver settings where patients have limited or no approved treatment options.

These programs build directly on the global commercialization platform we have established for LIVMARLI, CTEXLI, and CHOLBAM, heavily leveraging our existing technologies, people, and infrastructure. We plan to expand our U.S. and international teams starting later this year to reach liver healthcare providers in adult settings, including GIs, liver providers who manage PSC patients and hepatitis delta, as well as other care settings like infectious disease and selected primary care providers where we believe we can increase the number of diagnosed hepatitis delta patients. In the U.S., our current 20-person liver field commercial team reaches about 1,500 healthcare providers with currently focus on pediatric liver providers and some higher volume adult pro-providers. After our planned expansion to approximately 60 U.S. field commercial personnel, we anticipate being able to reach over 4,000 liver healthcare professionals, representing the vast majority of potential prescribers for our rare liver business.

Turning to our rare genetic disease business, we are very excited by the addition of zilurgisertib for the treatment of FOP, where there remains a desperate need for additional treatment options. FOP is a devastating, relentlessly progressive condition in which soft tissues such as muscles, tendons, and ligaments gradually turn into a second skeleton, leading to cumulative loss of mobility, severe disability, and early mortality. FOP is a highly concentrated ultra-rare disease with an estimated prevalence of about 1 per million, which translates to approximately 300 patients in the U.S. and around 900 patients globally. Patients with FOP are largely managed by specialized tertiary centers, with most of these centers also in the patients currently SOTEXELly allowing our rare gene commercial support. We've got data from the real study, secondary endpoint on the basis of validation.

We look forward to the presentation of the progress at upcoming medical. The zilurgisertib had it for priority by the FDA September 2026. Approved, we use zilurgisertib with several countries in 2027. We had it about the initiative, which we a potential system for our rating business. PP $7,200 million. This has been this for medical and capabilities action for support operating from oldest let go. With that error to review results. Here an idea. The song here with continuing in the commercial monitoring through.

Eric Bjerkholt
CFO, Mirum Pharmaceuticals

Disciplined investment behind our pipeline, which remains on track across all programs. Today, I'll walk you through the financials for the quarter, including an overview of the impact of the Bluejay acquisition and the zilurgisertib transaction. The net product sales for the 1st quarter were $160 million compared to net product sales of $112 million in the 1st quarter of last year. Cash, cash equivalents, and investments as of March 31st were $421 million, compared with $391 million at the beginning of the year. In the 1st quarter, the cash contribution margin from our commercial business was in the mid-50s%, and cash flow from operations was about $2 million. 1st quarter financials were significantly impacted by one-time expenses related to the acquisition of Bluejay Therapeutics, which closed in January of this year.

The total net cash outflow related to this acquisition was $253 million, which was offset through net financing proceeds of approximately $260 million. Total operating expense for the quarter ended March 31st was $949 million, which includes $761 million in expense associated with the acquisition of Bluejay, R&D expense of $98 million, SG&A expense of $96 million, and cost of sales of $29 million. Expenses for the quarter included stock-based compensation, intangible amortization, and other non-cash expenses of $64 million, including $35 million of stock-based compensation expense associated with the acquisition of Bluejay. The intangible amortization and other non-cash item expenses are largely reflected in our Chris and Peter mentioned we recently entered into an exclusive license agreement with Incyte.

In return for worldwide rights to the zilurgisertib, Incyte received an upfront payment of $60 million and is eligible to receive additional development and regulatory milestone payments, including $25 million upon U.S. FDA approval for FOP, ownership of a rare pediatric disease priority review voucher, if awarded, as well as sales-based milestones and tiered royalties on worldwide net sales in the mid to high single-digit % range. As we've discussed previously, we expect R&D expense to step up in 2026 as we invest behind brelovitug ahead of the anticipated BLA submission next year. For example, R&D expense in the 1st quarter included $21 million related to the development of brelovitug. Importantly, this expense expected increase is fully funded. We are continuing to scale the business with discipline, balancing investment in growth with a strong balance sheet and financial independence.

This approach positions us to advance our pipeline and execute on upcoming milestones without compromising our long-term financial strength. I'll now turn the call back to Chris for closing remarks.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks, Eric. Mirum's in a strong position after a very busy first of the year. What is most encouraging about the quarter is not just the number of positive updates, but how clearly they fit together. We continue to grow our commercial medicines. We're expanding our rare liver business into larger indications. We've added what we believe is a transformational medicine to our rare genetic business. Importantly, this is all coming together within a high-impact scalable business model. We're excited about the progress ahead as we approach multiple pivotal readouts, potential regulatory submissions, and potential new product launches. I'd also like to thank the entire Mirum team for all the hard work in getting us where we are today. Your dedication brings new treatment options to patients around the world. With that, operator, please open the call for questions.

Operator

We will now begin the question-and-answer session. If you would like to ask a question, please press star 1 to raise your hand. To withdraw your question, 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 now while we compile the Q&A roster. Your first question comes from the line of Gavin Clark-Gartner with Evercore ISI. Your line is open. Please go ahead.

Yesha Patel
Analyst, Evercore ISI

Hi, this is Yesha Patel on for Gavin. I just had one on FOP. Wondering your current view on the number of diagnosed FOP patients in the U.S. based on claims, patient advocacy, and provider research. How many of those patients will immediately be treatable at launch? I have one follow-up on LIVMARLI.

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah, thanks for the questions. You know, we point towards the approximately 300 identified patients in the U.S., coming from a patient advocacy group, IFOPA. In terms of addressable patients, you know, probably the main feature there is the NDA application Incyte filed is for age 12 and over. That'd be the main piece to consider, which would be the majority of the relevant patients.

Yesha Patel
Analyst, Evercore ISI

In terms of LIVMARLI, specifically on the guidance raise, wondering what's kind of driving the bulk of that increase. Is it due to the ex-U.S. expansion or kind of the continued PFIC ramp? Within PFIC, is the contribution still skewing towards those older patients?

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah. Thanks for the question. I mean, certainly LIVMARLI U.S. PFIC was the biggest driver, and continue to see both pediatric and adult patients come to treatment. I think the, you know, the older adolescents and adults really is the major driver, although we're still, we think, still in early innings. We've made good progress educating adult providers on genetic testing, but probably still the minority of them are actually doing that. I think there's probably more adult patients to find out there could potentially benefit from LIVMARLI. Just on the international piece, you know, in Q1, historically, we've seen a bit more seasonality and a little bit of a softer number in Q1, and that just wasn't as much of a factor this year.

Somewhat also in part of not only additional countries performing, but also PFIC starting to show up in that international number.

Yesha Patel
Analyst, Evercore ISI

Thank you.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the questions.

Operator

Your next call comes from the line of Josh Schimmer with Cantor. Your line is open.

Josh Schimmer
Analyst, Cantor Fitzgerald

Great.

Operator

Please go ahead.

Josh Schimmer
Analyst, Cantor Fitzgerald

Great. Thanks so much for taking the questions. Also on the zilurgisertib, how are you thinking about its differentiation versus maybe some of the other programs in development, garetosmab, if I'm pronouncing that right? SOHONOS, that's number 1. Number 2, are you planning to explore the program in other ossification indications, disorders? Number 3, I think I heard you say peak sales for the asset of $200 million. Is that global or U.S.? Thank you.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks, Josh, for the questions. Yeah, just to clarify the, that peak 200+ is a global number for us. In, in terms of, kind of positioning here, you know, the programs that you covered there, those are the ones that we're tracking. SOHONOS being approved.

The other program being in registration phase. For SOHONOS, you know, the data coming out of the PROGRESS study here for zilurgisertib is a real step forward in terms of the overall activity profile and tolerability and safety profile. We see the clinical data here being a quite meaningful advance on what's currently available in the market, which has quite a few limitations to it. Compared to the pipeline, this is an oral, which we see as a big advantage, and particularly in the setting where you can potentially drive ossifications from injections and some of these other interventions. Having an oral we see as a nice differentiator for the program.

Josh Schimmer
Analyst, Cantor Fitzgerald

Got it. Plans for other ossification disorders?

Chris Peetz
CEO, Mirum Pharmaceuticals

You know, It's still early days in thinking about it. I, you know, at this point wanna stay very focused on getting this launched for FOP. It's certainly something we'll consider as we get further down the road.

Josh Schimmer
Analyst, Cantor Fitzgerald

Okay. Thanks very much.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the questions.

Operator

Your next call comes from the line of John Wolinben with Citizens. Your line is open. Please go ahead.

Jon Wolleben
Analyst, Citizens JMP

Hey. Hey, thanks for taking the question. You know, little unusual having something under review where I haven't seen any of the data for, just wondering what you guys have been privy to to make you comfortable with this acquisition, and then, you know, what would be the form for it to make sense to get this out into the public domain?

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah, thanks for the question, Jon, and fully appreciate the uniqueness of the situation. You know, in our review, This is a conversation that actually has been going on for quite some time, as is typical for a license transaction like this. We've had full access to clinical data, to the regulatory correspondence, and the NDA. We feel quite confident in the profile for zolegorsertib and where they're at in the regulatory process. From the Incyte side, where they've done a fantastic job putting together this program, and saw it, you know, fitting better in a rare disease company like Mirum. You know, the work they've done on it is quite strong. They want to have the data presented first at a medical meeting.

We're hopeful that's happening relatively soon. Once we get that presented, we'll be able to share more on the pivotal data and overall product profile.

Jon Wolleben
Analyst, Citizens JMP

Will you guys be eligible for a pediatric review voucher if approved?

Chris Peetz
CEO, Mirum Pharmaceuticals

We do expect this to be eligible for a voucher. Under the terms of the agreement, Incyte will keep that voucher, and we will launch.

the product. The way operationally this works is Incyte is kind of, given they're mid-stride with the filing and review, they'll complete the primary role through approval, then we'll take over sponsorship at the point of U.S. approval.

Jon Wolleben
Analyst, Citizens JMP

Got it. Okay. Thanks, Chris.

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah. Thanks for the questions.

Operator

Your next question comes from the line of Michael Oles with Morgan Stanley. Your line is open. Please go ahead.

Speaker 18

Hi, this is Rohit on for Mike. Thanks for taking our questions. With the recent pipeline acquisitions, can you talk about how you're thinking about BD moving forward? Also, can you just talk about how you're thinking about pricing in FOP? Thanks.

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah. I can start and I'll hand it over to Peter. You know, I think, as you've seen now from Mirum, kind of over the history of the company, we see a priority in staying active on the BD front. That's how you find unique opportunities that fit and add value to the company. We will continue to work to find good programs to bring into the team. Maybe have Peter kinda touch on any more on that or the second part of the question.

Peter Radovich
President and COO, Mirum Pharmaceuticals

Yeah, I mean, nothing more on the BD strategy on the zolegorsertib. Pricing, obviously we'll make a decision and communicate that, you know, closer to approval. Just, you know, thinking about a U.S., I mean, you can look at the Niemann-Pick C products and other ultra-rare settings like that where you have a strong value proposition and similar ASP is probably get you in the ballpark.

Speaker 18

Thank you.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the question.

Operator

Your next question comes from the line of James Condulis with Stifel. Your line is open. Please go ahead.

James Condulis
Analyst, Stifel

Hey, thanks for taking my question, and congrats on the order. You know, maybe one follow-up on HDV. I think, you know, where I've we've heard a couple questions is maybe in the 900 mg monthly arm, specifically as it relates to, you know, the TND virologic response is maybe a little bit of an outlier relative to, like, some of your prior data and other, you know, the rest of your sort of dataset. Just, like, curious your perspectives here and, you know, as you think about the commercial opportunity here. For docs in the real world, what do you think is kind of the most important measure as it relates to, you know, evaluating efficacy for these different drugs?

Is it that, you know, TND virologic response, other measures of virologic response, the composite? You know, just curious your perspective there. Thanks.

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah. Thanks for the question. I'll maybe make a couple comments then have Joanne speak to some of the data that we're seeing out of the AZURE-1 Phase II-B portion. I think in terms of what we're, you know, focused on and what we think is most relevant for ultimate use and driving adoption here is that composite of virologic response and ALT normalization. Those two factors are really what's pointed to in the FDA guidance and shows that you're not only addressing the viral load, but you're also addressing the liver inflammation that is part of the disease. Seeing both of those move means you're kind of going after both components of both of the considerations for both the infection and the liver.

Maybe I'll ask Joanne to touch on the data we've seen to date.

Joanne Quan
Chief Medical Officer, Mirum Pharmaceuticals

Yeah. You know, Chris was talking about the composites, you know, all very true. When we look at the, you know, curves in terms of the virologic response, we do see declines in everyone. You know, when you structure the endpoint, if you don't meet a certain point by week 24, then you're either on one side of the line or the other. We do see decreases in all of the patients. There's certainly no evidence of lack of response or resistance or anything like that. Really, you know, partly it's an artifact of time. We do see deepening response with continued treatment. You know, and again, this is a fairly small, numerically fairly small group.

We'll have a lot more information with the full AZURE-1 and AZURE-4 phase III datasets to make, you know, to make a final call on that.

James Condulis
Analyst, Stifel

Makes sense. Thank you.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the question, James.

Operator

Your next question comes from the line of Brian Skorney with Baird. Your line is open. Please go ahead.

Brian Skorney
Analyst, Baird

Hey, good afternoon, guys. Thanks for taking my question, and great quarter. I guess I'd love to also ask a question on FOP too. It seems like you're doubling down on making hits in your corporate nemesis. I'm just wondering if you could kind of give your broad thoughts on where you think SOHONOS's profile leaves an opportunity for another entrant and compare and contrast how zilurgisertib might address these. The timeline would put us right around mid-cycle review with the FDA right now. I'm just wondering if you could say if that has already happened or is still pending.

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah. Thanks for the question. On the review, yes, that has happened, and I'd just say things are tracking as expected. Maybe I'll ask Peter to comment on a little bit more on positioning.

Peter Radovich
President and COO, Mirum Pharmaceuticals

Yeah. I think, certainly the feedback we've heard from, you know, stakeholders, patients, caregivers, physicians, others, available therapy in the market today, you know, there's a lot to be desired, you know, in terms of both efficacy and safety. Yeah, you know, we'll obviously be able to get into more details once we have the PROGRESS data presented at an upcoming medical conference. You know, from what we've seen in our review, there's a more conservative profile, really exciting about, you know, what it can mean for these patients, both efficacy-wise as well as a convenient oral and well-tolerated regimen.

Brian Skorney
Analyst, Baird

Great. Thank you.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the questions.

Operator

Your next question comes from the line of Lisa Walter with RBC Capital. Your line is open. Please go ahead.

Lisa Walter
Analyst, RBC Capital Markets

Oh, great. Thanks so much for taking our question. Maybe just some more details you can share on the opportunity for FOP. Are there any overlap with your current call points? Did you disclose the deal terms with Incyte? Maybe just one more. You know, given the recent positive results in HDV and PSC, wondering if this has impacted your thinking on when Mirum could become a profitable company. Thanks so much for taking our questions.

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah. Maybe I'll ask Peter to kinda speak to the FOP points and then have Eric kinda give some financial forward-looking views.

Peter Radovich
President and COO, Mirum Pharmaceuticals

Yeah. Great over-overlap with our existing team, our rare genetics team that's focused on CTEXLI, CHOLBAM. We mentioned that, you know, the majority, the significant majority of the FOP, patients are cared for in settings, centers that also prescribe CTEXLI and CHOLBAM. Different prescribers most of the time. Some overlap in medical genetics. FOP has, you know, the biggest prescriber there will be endocrinologists. That's a new kind of position target. The center overlap for the is really high with our existing, rare genetics business. Excited about adding this product to that team.

Eric Bjerkholt
CFO, Mirum Pharmaceuticals

Yeah. Then on the financials, we did disclose the upfront license fee was $16 million, then the next milestone would be $25 million upon FDA approval. There's some other commercial milestones, also a royalty in a low to mid-to-high single-digit range. We expect after launch that this product will be accretive very, very quickly. Your question was also about path to profitability, and I think that's much more driven by brelovitug and volixibat, as well as our current commercial business. As we've said, we're spending a lot on R&D this year for both of those products. Profitability will be, you know, pushed out probably till 2028 on the GAAP basis.

Chris Peetz
CEO, Mirum Pharmaceuticals

Would reiterate that, you know, expect to be operating cash flow positive next year.

Eric Bjerkholt
CFO, Mirum Pharmaceuticals

Yes.

Operator

Your next question comes from the line of Jessica Fye with J.P. Morgan. Your line is open. Please go ahead.

Jessica Fye
Analyst, JPMorgan

Hey, guys. Good afternoon. Thanks for taking my question. Can you estimate the contribution to 1st quarter LIVMARLI sales from Alagille syndrome versus PFIC? Another one, FOP, just thinking about that market, what do you see as the penetration for palovarotene? Would you envision the ALK2 being used in combination with that drug? Thanks.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the questions. I mean, just briefly on LIVMARLI, you know, we typically aren't breaking out by indication, but what we can say is that PFIC is They're both growing, but PFIC is the bigger growth driver. Maybe pass the FOP question over to Peter.

Peter Radovich
President and COO, Mirum Pharmaceuticals

Yeah. When we look at the, you know, the U.S., the market where this medicine's available, CHOLBAM, it's probably a minority of diagnosed patients that are currently receiving it. We can see from pharmacy claims data, and that kinda, you know, matches what we've heard in physician and caregiver interviews. It, you know, it can be tried, but it can often be difficult to tolerate and stay on.

Jessica Fye
Analyst, JPMorgan

Thank you.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the question.

Operator

Your next question comes from the line of Mani Foroohar with Leerink Partners. Your line is open. Please go ahead.

Speaker 17

Hey, guys. You have Ryan on for Mani. Thanks for taking our question, and congrats on the quarter. Maybe just circling back to FOP, what's the latest thinking here on an OUS filing and when you guys would expect to launch there? Then just going back to the peak sales of $200 million, we're just wondering, is that in the 12-plus age group that you guys would get approved in the upcoming? How should we think about upcoming data for the younger age groups that are being tested? Thanks.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the questions, Ryan. On OUS strategy, actually, a European filing is upcoming, so we could actually still have that in this quarter. Incyte is still driving those activities. You know, again, their team's doing a great job. In terms of the overall, you know, peak estimate, that $200 million-plus, that's the full brand in FOP over life cycles, the way we look at it. The younger age patients, you know, we do expect that the label would launch with the 12 and older. There are 2 other cohorts in the study that are ongoing that would support potentially taking that age lower over the near term, frankly. Those are ongoing enrolling now, they're not too far out.

Ryan Deschner
Analyst, Raymond James

Awesome. Thanks.

Chris Peetz
CEO, Mirum Pharmaceuticals

Great. Thanks for the questions.

Operator

Your next question comes from the line of Ryan Deschner with Raymond James. Your line is open. Please go ahead.

Ryan Deschner
Analyst, Raymond James

Thanks, thanks for the question. A couple from me. You know, what's your strategy for identifying FOP patients in the U.S. and abroad and addressing the relatively high misdiagnosis rate for FOP? Do you anticipate any early line of sight into a substantial group of patients from Incyte's prior clinical studies or maybe a compassionate use program or something like that in FOP? I have a follow-up. Thanks.

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah. Thanks for the question, Ryan. Yeah. The, you know, I think the FOP patients often have a longer diagnostic odyssey than they should. You know, there are patients who get diagnosed at birth, but often the I think the literature says the average age of diagnosis is seven years, and so obviously people have waited longer than that. I think that's improved with availability of genetic testing. You know, that's, I think, an opportunity to continue to raise awareness, just like all of our rare genetic diseases, to try to shorten that diagnostic odyssey as much as we can. We do think in the U.S., though, most of the, you know, a pretty substantial majority of the patients are identified with FOP.

Probably a different story, in, you know, middle and lower income countries. Was there a second question? Hey, did you have a follow-up, Ryan?

Ryan Deschner
Analyst, Raymond James

Just was also wondering if there was anything notable so far in the VISTAS extension in terms of rollover discontinuation rates, pruritus or other patient metrics that might take a little longer to modulate over time.

Chris Peetz
CEO, Mirum Pharmaceuticals

Yeah, I mean, Incyte does have a, you know, this PROGRESS study. You know, it's, you know, it's enrolling well, and I think we'll be able to disclose more about what they've seen from that at the upcoming medical conference. Have certainly seen a lot of physician and patient interest in the program.

Ryan Deschner
Analyst, Raymond James

Okay. Thanks very much.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the questions.

Operator

Your next question comes from the line of Joseph Thome with TD Cowen. Your line is open.

Joseph Thome
Analyst, TD Cowen

Hi there.

Operator

Please-

Joseph Thome
Analyst, TD Cowen

Hi. Hi there. Good afternoon. Thank you for taking my questions. Maybe 1 on FOP. I guess the level of IL-2 inhibition you're seeing with the therapy, I guess, do you think that could be enhanced by garetosmab, Regeneron's activin A drug, or are these largely just gonna be competitive therapeutics in the landscape? Second, when we think about the potential expansion opportunity for LIVMARLI in the basket trial that's gonna be reading out later this year, I guess how should we think about that in your overall projection for LIVMARLI? How much is this basket population? Thank you.

Chris Peetz
CEO, Mirum Pharmaceuticals

If I can make a quick comment on the garetosmab positioning. You know, it's probably best to get into more detail on this after our data is presented, so we can give a better, a more complete picture. We think the profile for zolegorsertib and its clinical positioning is really strong as a convenient oral single agent, and excited about bringing that forward. Maybe if Peter could take the follow-up.

Peter Radovich
President and COO, Mirum Pharmaceuticals

Yeah. No, you know, we've kind of talked about that indication, being about a third of the at least $1 billion peak sales, opportunity for LIVMARLI. You know, still reiterate that. Thank you.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the questions.

Operator

Your next question comes from the line of Charles Wallace with HCW. Your line is open. Please go ahead.

Charles Wallace
Analyst, H.C. Wainwright & Co.

Hi. This is Charles. I'm for RK. Thanks for taking my question. For FOP, another question on that. How many patients from the PROGRESS study, I think there was 63 in that study, do you expect will could come on after launch? Do you expect to have some sort of bridging program?

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks for the question, Charles. You know, given the kind of the nature of the relationship here, we're gonna wait until we have that data presented to give some of the detail on it. Overall, I think it's a really compelling profile, and the feedback has been positive. Just don't wanna get into specifics ahead of having that data presented.

Charles Wallace
Analyst, H.C. Wainwright & Co.

Okay. That's fair. I guess another question for Nate on the Salesforce expansion. You're growing it to 60 in the field. I just wanted to maybe get a little more color on when you expect these the team to be fully on board and also when do you expect them to be fully functional? Thank you.

Peter Radovich
President and COO, Mirum Pharmaceuticals

Yeah. you know, I kind of prepared a comment with starting this year, later this year. I kind of think, you know, early next year we'd be kind of fully on board and that team would, you know, cover both pediatric and adult settings where, you know, not just Alagille, and adult PFIC can be found, but also, you know, PSC and Delta. I think by early next year they'd be active in all those areas. Of course, with the pipeline products, the activity would really start upon potential FDA approval.

Charles Wallace
Analyst, H.C. Wainwright & Co.

Great. Thanks for taking my questions, and congrats on a great quarter.

Chris Peetz
CEO, Mirum Pharmaceuticals

Thanks. Yeah, thanks for the questions.

Operator

There are no further questions at this time. I would now like to turn the call back to Chris Peetz for closing remarks.

Chris Peetz
CEO, Mirum Pharmaceuticals

All right. Well, thank you all for joining us today and for all the support and a great start to 2026. Have a great afternoon.

Operator

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

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