With Andrew McKibben, Senior Vice President of Mirum Pharmaceuticals. Mirum is a biopharmaceutical company developing and commercializing therapies for the treatment of rare diseases. The company currently commercializes three small molecule drug products: LIVMARLI, CHOLBAM, and CTEXLI as therapies for rare diseases. At the back of robust first half 2025 revenue gains compared to 2024, management raised their revenue guidance to a range of $490 million - $510 million for 2025. The company also has two candidates in mid-stage clinical studies that will start reading out in mid-2026. To talk about the growth in 2025 and beyond, let's get started with Andrew. Good morning, Andrew. Glad to see you here, and thanks for accepting our invitation and talking to our audience today. Andrew, for starters, could you please describe the corporate mandate of Mirum and also a brief description of the three commercial drugs that you have? Yeah, sure, and thanks for having me. Very happy to be here. Just as a disclaimer, we'll be making forward-looking statements, so please refer to our risk factors and our SEC filings. To your question, Mirum was founded in late 2018 as a rare disease company around LIVMARLI and volixibat. Fast-forwarding to today, we have three approved commercial medicines. We're on track for $490 million- $510 million in revenues this year, and the business is operating cash flow positive. We've got a strong balance sheet and a pipeline that we're really excited about with three potentially pivotal readouts between now and the first half of 2027. We're really in a strong place to grow, continue to grow, and grow the company, and we feel like we're well positioned to do that. For the three medicines, just to answer that part of the question, LIVMARLI is approved in two indications: Alagille syndrome and PFIC. These are both settings of cholestasis in primarily pediatrics, but what we're seeing in PFIC is that that kind of is actually a little bit more prevalent in the adult population than we thought. CTEXLI is approved for CTX. We got that approval earlier this year. It had previously been used as standard of care in the setting, but this approval grants us seven years of orphan exclusivity and allows us to do more to promote and support patient finding. Then CHOLBAM is approved for bile acid synthesis disorders, which is kind of a basket of indications where you have patients who are not able to synthesize cholic acid effectively. You're actually kind of replacing what they can produce. To talk about LIVMARLI, around which the company was put together, it has been a major driver of revenue growth, especially in the first half of 2025. As you said, the PFIC, or the progressive familial intrahepatic cholestasis indication, has been a major label expansion, which you received in mid-2024. How has that market been growing? Also, how is this new label expansion helping to identify patients, especially in the pediatric population? Yeah, it's been interesting. You know, LIVMARLI was not the first IBAT approved in PFIC, and I'd say our expectations were kind of fairly modest going into the launch in this setting. We have a very strong clinical profile. I think LIVMARLI is differentiated on that front in terms of the benefits that we see in pruritus, growth, bilirubin improvements. We think that we thought that would play well. What we found since we've been out there and promoting, one is that hypothesis that the differentiated clinical profile and matter is true. We do see some preference for the brand in that sense. What's surprised us is that we have found diagnosed patients that just have been IBAT naive. There was more PFIC out there to capture than we thought. Crucially, there's also a perception that we observed amongst more of the adult hepatologists that PFIC is an infant-onset condition. In reality, it's an umbrella of different genetic mutations that fall under the umbrella of PFIC, but some of those show up later in life. We've been pretty successful driving awareness in the adult settings of the fact that some of this idiopathic undiagnosed cholestasis might actually be PFIC. We sponsor a genetic test that helps facilitate the process and have seen some results come from there too. Overall growth is in winning new incident patients, picking up patients that just hadn't had an IBAT yet, and then finding new patients. PFIC is turning out to be larger than we thought. Fantastic. Outside of LIVMARLI, are there any other factors that potentially are showing up as a positive surprise for you guys in terms of the revenue growth in 2025? Can we expect any of that to show up again in 2026 and beyond? Yeah, the other factor that kind of led to our guidance raise, beyond some of the PFIC performance, was the performance of the international business. That continues to be strong. Our partner in Japan, Takeda, recently received approval for both Alagille and PFIC, and they're starting to launch. Overall, that's been across our partners in Japan, our distributor partners, and our core business in Europe. It's been going quite well. That's been a pleasant surprise too. The company is also trying to expand the label of LIVMARLI, especially trying to look at the additional settings of cholestatic pruritus by conducting this EXPAND trial. What's the market that you're going after if we get that label expansion with a successful EXPAND trial? Yeah, so it's an interesting kind of basket study. We've seen a lot of interest from prescribing physicians for using an IBAT in other settings of cholestasis where you basically have an underlying driver, but the kind of characteristic elevation of certain bile acids and resulting pruritus. The kind of case experience that we've seen to date has been really positive, and there's clearly demand. We have kind of a line of sight here to at least 500 pediatric patients in the U.S. Frankly, it's probably larger than that, but based on the work that we've done, that feels like a very tangible population that we'd be able to capture. We're running a study in this setting. It's basically a study of exclusion. If you don't have Alagille, PFIC, PSC, PBC, but you have the kind of symptoms and kind of characteristics of cholestasis, you qualify. That study has both a pediatric element, which is the primary analysis. There's also a cohort of adult patients as well. That study is in a lot of interest and enrolling well. Expect to complete enrollment in that next year. It's a 20-week endpoint, so it points to data roughly in the first half of 2027. Perfect. In terms of future growth, let's talk through your clinical pipeline. As you're progressing with the VISTAS study with volixibat as a treatment for PSC, what is the indication itself, and what's the size of this market? Yeah, we think in PSC, we're quite excited about it. We just announced that we completed enrollment in the study on Monday. That puts us squarely on track for a top-line readout in Q2 of next year. Of the two opportunities we're looking at with volixibat, PSC we expect to come first. It's 30,000 or more patients in the U.S. The majority of these patients have itch, so it would be on label. We're pursuing an endpoint in the setting of improvement in cholestatic pruritus. The beauty of this approach, and I think what differentiates our PSC program, is that this is pruritus as an outcome. This is an endpoint that confers full approval, which has been the historical challenge in this setting: how do you find a path to approval with a surrogate and in a fallen outcome study? This is an outcome. It's kind of an elegant way to bring a therapy to this patient population and address a very high unmet need that, when you talk to the patient community, is a real significant burden that I think is underappreciated. When we look at that overall population and the opportunity, about 20,000 patients or so, so 2/3 have active itch. When you think about anchoring pricing, we have benchmarks with the PPARs out there. Pretty easy to see this being quite a substantial opportunity for us. Is the standard of care PPAR or are there other drugs for this? Nothing is approved. Okay. It has been a challenge in PSC for a long time. I think the patient community is really looking for something. You do see the typical off-label therapies used that you see across these cholestatic settings, but nothing has been shown to really move the needle for these patients. Regarding the VISTAS study, as you said, we should be expecting data in the second quarter of next year. As investors get ready for that event, what would you consider as positive data? That'll make us think about getting to the next stage, whether it's phase III or even to get in front of the FDA and look for an approval. Yeah, I mean, we've structured this study to support registration. The endpoint, the statistical analysis plan, the study size has all been discussed with the FDA. Our intent would be to file with this data set. In terms of what is the bar here, nothing's approved, but when you kind of look at the universe of pruritus studies, typically what you want to see is beating placebo by a point. You'd like to see, in general, a 2-point absolute improvement from the baseline on a 0-10 scale. The data that we've seen to date with IBATs in both PSC and PBC suggests that we should be above that threshold. That's kind of the floor for approval typically is how we think about it roughly. Since you just talked about PBC, volixibat is also being evaluated for primary biliary cholangitis. In the VANTAGE study, I know you recently announced some positive data from that trial and you expect enrollment to complete in 2026. If you can help us understand how the study is designed, what were the recent data updates that you provided, and how should we think about the program itself? Yeah, so, in this very similar design to the PSC study, about a 28-week endpoint measuring pruritus, PSC and PBC are evaluating the same dose. We did have a very nice interim data readout where we saw a very rapid and deep response on pruritus, so over a 2-point improvement versus placebo, close to a 4-point absolute improvement. Also saw benefits in fatigue, which is another kind of paired with pruritus, the two major burdens for both PSC and PBC patients. Really like how our profile is shaping up from the interim data, which was what we shared at EASL a couple of months ago, that kind of 28-week data set from those 30 patients in the interim. We're now doing the confirmatory portion. It's about 200 patients. It's not clearly not sized for power. We had a lot of zeros in our P-value at the interim. This is really more about meeting the requirements from a safety database perspective, which is why it's larger and taking a little bit more time to enroll. Enrollment's progressing quite well. We're really excited about it and looking forward to getting to see the full profile. Regarding this indication, I believe there is some competition there. How do you position volixibat in the competitive environment? Yeah, so kind of two aspects to it. I mean, I think the first is understanding there's lines of care in PBC, and most of the approvals to date have been in the second-line setting of patients who do not achieve, you know, full control of their kind of biochemical markers on generic UDCA. That's where you see the PPARs approved. Our approach is we are agnostic to line of therapy. You know, you see pruritus across the board in the first-line setting where patients are on UDCA, but that does nothing for pruritus. In the second-line setting where you have patients who are going to be increasingly on PPARs, I think the PPAR benefit on pruritus is, you know, it's there, but not optimal. A portion of patients do have a nice benefit, but conversely, a portion don't. An IBAT can be a candidate in either setting, the primary opportunity being in that first-line population where you've got about 2/3 of the patients actually. Our study has no criteria for that. We actually have some patients who are on PPARs in the interim data set who presented with moderate to severe pruritus. Effectively, a broader setting and dosing on top of whatever the patient's taking for those doses. The other interesting program that you have is the one with the 3379 being evaluated in another rare indication, which is Fragile X syndrome. What is Fragile X syndrome and how big of a market opportunity do you have over there? Is there any competition at all in that space? Yeah, we're another indication we're very excited about. This is also a larger rare setting. Around 25,000 patients in the U.S., if you're looking at just the male segment, about a comparable proportion in Europe. Fragile X is a genetic mutation that is one of the leading causes of autism spectrum disorder. Effectively, what happens with this mutation is the levels of cyclic AMP in your neurons are depressed, which puts your neurons in a hyperactive state, which then prevents you from forming synapses that are crucial to just normal learning, memory, cognition. That excited state also kind of confers some behavioral aspects of the disease too that can be challenging. PDE4D, this mechanism, we're excited about it because this directly inhibits the conversion of cyclic AMP. It helps raise those levels back to normal in the brain. What you've seen in the preclinical data and what we've seen in the proof of concept work that was done by our competitor is that it's doing exactly what you'd expect. You see improvements in cognition preclinically. You see improvements in synaptic formation. That effect is sticky. Even when you stop dosing, those synapses that you formed stick around. That's what got us excited about 3379, which is differentiated from Shionogi's compound, also a PDE4D inhibitor, in that it's more brain penetrant. We can get more PDE4D inhibition where we want it with less drug, which ultimately, that's the hypothesis we'll be testing in our phase II, but has the potential to be differentiated on safety, efficacy, or both. Interestingly, we should be seeing Shionogi's data in later this year. That's our expectation. They have not, I don't think they've guided to timing, but that's our guess. For us, doing the experiment, understanding what we have is crucial. We're not waiting to see competitor data. I don't think we'll learn enough from that readout to really inform at that time enough of what we want to do. I think it's important for us to understand what we have and what we're working with. In terms of the clinical program there, when do you plan to start this dose-ranging study? Beyond that, I'm imagining the data should be available in a year or a year and a half from then. How large of a phase III program do you need to do for this? We'll see on how large the phase III needs to be. Our phase II will be starting later this year, Q4. There's, I think, some delineation of age that needs to be explored. If you get into, you can make a case for treating in younger patients, but brain development matters. Looking at those patients separately is important. When you're younger, your brain is still forming and there could be some benefit to treating earlier. When you're treating an adult and the brain is largely kind of set, it's different. That's in part why we have, in our phase II, we're looking at 16 and older in the main component of the study, three doses, 52 patients per arm, placebo arm. We have an open label study in patients younger than 16 to kind of understand if there's any difference in response just based on age. As we go to a phase III, I think depending on the phase II results and what we see from Shionogi, that will kind of dictate the design. It's a bit too early to say there. In terms of other catalysts, whether it's commercial or clinical, what should we expect towards, let's say, over the next 6- 12 months? I'd say on the commercial side, continued execution. All three medicines are growing and growing well, and we expect that to continue. On the clinical side, we are starting the phase II in Fragile X this year, and I think have a lot to look forward to as we get into 2026, starting with PSC. The enrollment completion milestones that year for both the EXPAND PBC and then the subsequent data. Everything is on track, and we're pushing these forward as quickly as we can and very excited to get on the other end of these data readouts. Perfect. Lastly, your balance sheet is certainly strong and, you know, you have a growing revenue base at this point. What are your thoughts about growing the portfolio on the clinical side? If you so decide to do some in-licensing, you know, what areas or what therapeutic areas would you be looking at? We'll stay in rare. Generally, I'd say it's always an active effort. We don't have to do anything. We really like what we have in the company, which is a nice place to be in when you're looking because you have the luxury of being able to be disciplined. We work very hard to be disciplined. We've got the company in a great financial position. We are self-sustaining. We don't intend to compromise that. When we look for stuff in the rare space, we have to be able to add value to it. It's got to be a very clear story and fit with our current capabilities. There are some obvious synergies that we can build on. There needs to be data that we can believe in. We're not going too early. Fragile X is a good example of kind of that profile. I'd say it's got to be transactable and that's not always easy. Hitting all four of those criteria is a challenge, but we're actively looking. Thank you, Andrew. Thanks for your time and good luck. Appreciate it.