Good afternoon, and welcome to Ultragenyx' First Quarter 2026 Financial Results Conference Call. At this time, all participants are on a listen-only mode. At the end of the prepared remarks, you will have an opportunity to ask questions during the Q&A portion of the call. It is now my pleasure to introduce your host, Joshua Higa, Vice President of Investor Relations. Thank you. We have issued a press release detailing our financial results, which you can find on our website at ultragenyx.com. Joining me on this call are Emil Kakkis, Chief Executive Officer and President, Erik Harris, Chief Commercial Officer, Howard Horn, Chief Financial Officer, and Eric Crombez, Chief Medical Officer. I'd like to remind everyone that during today's call, we will be making forward-looking statements. These statements are subject to certain risks and uncertainties. Our actual results may differ materially. Please refer to the risk factors discussed in our latest SEC filings. I'll now turn the call over to Emil. Thanks, Josh. Good afternoon, everyone. We are now in our 16th year since our founding. This year is expected to be transformative with growing revenue and multiple new drug approvals. We are on track to well exceed $700 million in revenue from our global commercial business with a consistent track record of double-digit annual revenue growth. We have a PDUFA date for two gene therapies that would bring first-ever treatments to patients and families with no other disease-modifying options. Also, we will unblind our phase III Aspire study evaluating GTX-102 in patients with Angelman syndrome in the second half of this year. We continue to execute global clinical trials across the largest late-stage pipeline in rare diseases. We are also manufacturing our gene therapy products in our new facility in Bedford, Massachusetts. I'll start with GTX-102 for Angelman syndrome. The first patients enrolled in the phase III Aspire study have reached their day 338 visit and have transitioned to open- label extension study. The rest of the patients will be completing the blinded portion of the study in the next few months and crossing over to open label extension. With the Aurora study, we are expanding GTX-102 treatment to other ages and genetic types of Angelman syndrome, and enrollment in that study continues to go well. We prefer to develop the first-ever treatments for diseases that have not had significant breakthroughs in the past, and so do not typically work in disease areas where there are other competitor programs at similar stages of development. In the case of Angelman syndrome, we made an exception given the size indication and the excellent work GeneTx had done with the scientist Scott Dindot to develop a potent ASO that worked in a large animal model rather than just mice, which often do not predict human biology. The preclinical research Scott conducted in his lab at Texas A&M is a tour de force of molecular genetics. He was able to identify and target a separate and distinct region of the Angelman's message transcript that has led to more efficient transcript knockdown and greater potency in the clinic. This list of superior science has led us to study Angelman syndrome. Later in the call, Dr. Crombez will walk through the longer-term efficacy, durability, and safety data from the phase I-II study in his section. I want to highlight now that we have 66 patients on therapy for an average of three years and with the longest approaching five years, with continuing and improving benefits across multiple domains and with a favorable safety profile. Based on this longer-term data, we believe GTX-102 can deliver clinically meaningful treatment effects and can be safely administered in chronic dosing. What we see in the phase I/II data, we believe GTX-102 is making an important difference in the lives of these patients and their families. Shifting now to our global commercial efforts. Our commercial business continues to deliver. We're now generating revenue in more than 35 countries, a result of strategically investing in high-quality teams who can efficiently navigate the complex approval and reimbursement processes around the world. This reflects a disciplined country-by-country execution our teams deliver every quarter. This base business is not only generating meaningful and growing revenue, it is the engine that will power our next phase of growth. Our teams currently commercializing DOJOLVI and MEPSEVII are poised to add DTX401 and UX111 to their responsibilities as we look forward to approvals for these two products later this year. Our established global commercial business is bringing first-ever treatments to patients who need them, paving the path to profitability in 2027. I'll now turn the call over to our Chief Commercial Officer, Erik Harris, who will provide details on his team's efforts in the first quarter. Thank you, good afternoon, everyone. As Emil mentioned, the underlying business remains strong, and we are well-positioned to capitalize on the potential upcoming launches. Howard will share details, but we remain fully confident in our 2026 revenue guidance. Throughout the first quarter, the commercial and field teams have continued to meet the growing demand for our products across the globe. I'll start with CRYSVITA and want to put the first quarter revenue in the right context. The revenue in North America, Latin America, and Turkey was consistent with our expectations in the ordering patterns we have seen in prior years. This is a business we know well. We see continued strength in the underlying demand across all of our regions, including in markets like Brazil, where bulk orders by the Ministry of Health can result in quarter-to-quarter variability. In Latin America, approximately 30 patients began commercial therapy in the first quarter. Bringing the total number of patients on CRYSVITA to more than 950 in the region. We remain fully confident in the fundamentals and strength of the business along with our partner KKC in North America, our ability to continue to find and treat patients with XLH and TIO. Shifting now to DOJOLVI, where the trend of our steady growth continues six years post-approval. In the first quarter, our North American team generated more than 30 start forms, far exceeding their target for the quarter. In North America, we now have more than 675 patients on reimbursed therapy, and in Europe there are approximately 300 being treated through named patient or early access programs. The next stage of growth is likely to come from Japan, where DOJOLVI was granted conditional approval last year. We look forward to the full approval and launch of the product this quarter. I'll close with EVKEEZA, which is another example of our experienced team's ability to successfully commercialize rare disease products. In our region outside of the United States, we are seeing exceptional growth from this program as our international commercial teams navigate the country-by-country reimbursement process and respond to requests for early access from patients and their physicians. In total, there are approximately 370 patients across 18 countries who are receiving EVKEEZA. We expect this will continue to be an important and growing contributor to our revenue base. Beyond the individual product performance, I want to step back and highlight what I believe is the true strength of this business, the scale and reach of our global commercial infrastructure. That depth of market presence across rare disease markets that require significant expertise, patient-finding capability, and reimbursement navigation is a genuine advantage. It is what enables us to efficiently bring first-ever treatments to rare disease patients. Critically, this infrastructure and experienced team are what give me confidence as we look toward the rest of the year. My team is preparing for two new product launches, DTX401 with a PDUFA date of August 23, 2026, and UX111 with a PDUFA date of September 19, 2026. The launch readiness work is well underway across both programs, We are building on the infrastructure and expertise we have already established. With that, I'll turn the call to Howard to share more details on our financial results and guidance. Thank you, Erik, and good afternoon, everyone. I'll focus on our first quarter financial results and guidance for the year. Starting with revenue. Total revenue for the first quarter of 2026 was $136 million. CRYSVITA contributed $93 million, including $39 million from North America, $46 million from Latin America and Turkey, and $8 million from Europe, which were consistent with the anticipated quarterly timing and trends Erik just mentioned. DOJOLVI contributed $18 million, consistent with our expectation for steady demand growth. EVKEEZA also contributed $18 million, representing 64% growth over the first quarter of 2025 as demand continues to build following launches in our territories outside of the United States. Lastly, MEPSEVII contributed $7 million as we continue to treat patients in this ultra-rare indication. Total operating expenses for the quarter were $305 million, which included cost of sales of $30 million and combined R&D and SG&A expenses of $275 million. Total operating expenses included $30 million of non-cash stock-based compensation and $30 million of expenses related to the restructuring announced last quarter. For the quarter, net loss was $185 million or $1.84 per share. As of March 31, we had $534 million in cash equivalents and marketable securities. Net cash used in operations for the quarter was $197 million. Recall, in the first quarter of the year, we typically use more operating cash than in each of the subsequent three quarters because it includes items like the payment of annual bonuses. In addition, the first quarter of 2026 included $38 million in payments related to UX143 manufacturing activities as well as $5 million related to severance and other payments from our recent reduction in force. Net cash used in operations is expected to decrease in the remaining quarters of this year as we continue on our pathway to profitability in 2027. Shifting now to guidance for 2026. We are reaffirming the revenue guidance we provided in February. Total revenue in 2026 is expected to be between $730 million and $760 million, which represents 8%-13% growth over 2025 and excludes potential revenue from new product launches. CRYSVITA revenue is expected to be between $500 million and $520 million, which includes all regions and all forms of CRYSVITA revenue to Ultragenyx. This range reflects growing underlying global demand, partially offset by expected timing of ordering patterns in Brazil that we anticipate will normalize in 2027. The DOJOLVI revenue is expected to be between $100 million and $110 million. We are also reaffirming the R&D and SG&A guidance we provided on our last call. Specifically, we expect 2026 combined R&D and SG&A expenses to be flat to down low single digits versus 2025. We also continue to expect 2027 combined R&D and SG&A expenses to decrease at least 15% in 2027 versus 2025. With that, I'll turn the call to our Chief Medical Officer, Eric Crombez. Thank you, Howard. Good afternoon, everyone. As Emil mentioned in the opening, I'll focus on the clinically meaningful phase I/II data that we have generated with GTX-102, our antisense oligonucleotide for the treatment of Angelman syndrome. This data is from our phase I/II open label single-arm studies, which inform the design of the phase III double-blind, sham-controlled Aspire study. Given the differences in study design, these phase I/II results are not necessarily predictive of phase III outcomes. In our press release earlier today, we highlighted that a total of 74 patients have been treated with GTX-102 as part of our phase I/II program. This is one of our largest phase I/II studies we have conducted and was designed to inform the dose, dose regimen, and endpoints for our phase III studies. There are now 66 patients in long-term extension study, with patients generally receiving the 14-milligram quarterly intrathecal maintenance dose. These patients have now been on continuous therapy for an average of three years, and some patients are now in their fifth year of treatment. These patients continue to demonstrate improvement across multiple developmental domains, with no new cases of transient lower extremity weakness. We took a cut of this data in March of this year to be able to highlight the long-term safety and efficacy of GTX-102 in a forthcoming manuscript. I wanted to share a high-level summary today. Starting with the Bayley-4 cognitive raw score, there are 53 patients in the phase I/II study with a Bayley-4 cognitive raw score at month 12. At this time point, they were approaching a mean change from baseline of 10 points, exceeding the meaningful score difference of six points. With longer-term follow-up, we see continuing and improving benefits in cognition. Turning to the Multi-Domain Responder Index, or MDRI, that uses clinically meaningful score differences consistent with FDA guidance, as opposed to statistically driven changes, to determine a positive or negative response across five different developmental domains. In the phase I/II dataset, we now have MDRI data at month 12, 24, and 36 that evaluates response across cognition, communication, behavior, sleep, and gross motor. When comparing response to baseline, the P value across all three time points is less than 0.0001. Not only is this a very powerful statistical assessment of five different measures, it is consistent with doctors' and families' broader view of neurologic diseases like Angelman. It is the intersection of all of these developmental changes that reflect how individual patients truly respond to a treatment in a holistic way. In the 48-week Aspire phase III study, we have primary statistical alpha split between the Bayley-4 cognitive raw score and the MDRI. This is not a hierarchical evaluation, meaning that both of these endpoints will be tested in parallel. If the Bayley cognition hits less than 0.04, or if MDRI hits less than 0.01, we will have a statistically successful phase III study. We also took a look at expressive communication on our phase I/II study assessed by the Bayley-4. Similar to cognition, we saw meaningful improvements in expressive communication that continued and improved in longer-term follow-up. Based on the totality of data generated in our phase I/II program, I remain confident that the developmental progress and continued learning of new skills in these patients supports the meaningful benefit of using this ASO to provide UBE3A from the paternal allele. I'm looking forward to seeing the results from our phase III studies and the potential to replicate these results in larger controlled studies. I'll now turn the call back to Emil to provide a reminder of our catalysts for 2026 and some closing remarks. Thank you, Eric. I'll close with a few of the catalysts we have later this year. A full list can be seen in the corporate deck posted to our website. Starting with DTX401 for the treatment of glycogen storage disease type 1a, we continue to work well with the FDA and look forward to our PDUFA action date of August 23rd. The FDA has also informed us an ad com is not planned. Next, for UX111 for the treatment of Sanfilippo syndrome, the BLA that was resubmitted early this year is being reviewed with a PDUFA action date of September 19th. Lastly, GTX-102 for the treatment of Angelman syndrome, is on track for readout top-line phase III data in the Aspire study in the second half of the year. Ultragenyx has been one of the most productive companies in rare disease in the industry and taking drugs from early research to approved therapies for patients who have no other options. We've done it across multiple modalities, multiple therapeutic areas, and we look forward to bringing the next set of first-ever treatments to the patients' needs. The surge in late-stage programs in the last two years has challenged us like it would anyone. The benefit is once we turn the corner of these programs into approved products, we have the potential for a significant acceleration in our growth that will be a special moment in the history of Ultragenyx. With that, let's move on to your questions. Operator, please provide the Q&A instructions. Thank you. At this time, we'll be conducting a question-and-answer session. If you'd like to ask a question, please press star one on your telephone keypad. Confirmation tone will indicate your line is in the question queue. You may press star two if you'd like to remove your question from the queue. As a reminder, we ask that you please limit to one question and one follow-up. For participants using speaker equipment, it may be necessary to pick up your handset before pressing the star keys. One moment, please, while we poll for questions. Our first question comes from Tazeen Ahmad with Bank of America. Your line is now live. Hey, guys. This is Daniel on for Tazeen. Thank you for taking our question. I was just wondering if you could comment on the new update for Angelman. Like, what level of consistency are you seeing for patients improving on the Bayley-4 and the MDRI? You know, how we should think about variability between the two endpoints for the phase III? Thank you. I'll touch on it. Maybe Eric can add some more. I think the Bayley that we're conducting is being done with primarily with an outside firm that's coming and doing the test at the site. This is, we're running a very high-quality operation in terms of how we'll measure the test to help reduce variability. I think the consistency is something we can't comment on at this point in a phase III study, but we can talk about what, how it's looked in phase II. I think it should be expected to be similar to what we've seen before. I think the MDRI has been a very robust and consistent measure just in its nature because of its multiple domains that we've seen strong results, and I think Eric just talked about them. Eric, what do you think about the Bayley-4 consistency? Yeah. I think, you know, looking at the results from phase I, II, and very much applied to how we designed phase III, the most important thing we did was include patients with full deletions. This means they're expressing no UBE3A and gives you a very consistent patient population, driving those consistent results we saw in phase II and what we think will be replicated there. Then again, as a reminder, bringing patients with other mutations that add variability into our second phase III study, Aurora. Yeah, that's a very good point, Eric. Yeah. Consistent genotype will definitely help us get consistency, particularly consistency in what the placebo or the untreated or the sham will do because without treatment, patients with Angelman do not gain on the Bayley-4 significantly. Let's move on to the next question. Our next question comes from Joseph Schwartz with Leerink Partners. Your line is now live. Great. Thanks very much. A couple questions on GTX-102. In Aspire, are you stratifying randomization or pre-specifying subgroups by any baseline factors? It seems like in rare pediatric trials, even modest imbalances in baseline severity could be important, and there's some literature in Angelman that this could influence variability. I'm just wondering how confident you are that Aspire is protected against any potential baseline imbalances. Well, thank you. I'll let Eric answer specifically. In general, for all of our programs, we are very aware of the salt skewing issue on the randomization, so we will always, for primary endpoints, we'll stratify our primary endpoint, do our best we can. However, nothing is perfect. What are we doing for Angelman? Yeah. Specifically for Aspire, we stratify both by age and cognitive raw score. That being our primary endpoint, we wanna make sure we have consistent balance there. Okay. We noticed that you haven't narrowed the timing for Aspire top-line data yet. Do you have any sense when, during second half of 2026 you might report the data? Is late third quarter a good assumption since you finished enrollment in late July last year? It's fun, isn't it? Keeping you in the dark about exactly when it's happening. Yes. I think, you probably can guess based on the timing of things. The question is that when you close out an international study, a lot of endpoints, you do wanna do it carefully. We're not being precise on that only because we wanna give ourselves time to get everything straight before we do unblinding. We've said the second half, but you can tell by when last patient in was, you know, roughly when the trial should have the last patient out. The timing it takes to finish up a study with sham, there's EEGs, there's a lot of things in there that will take a little time. We, you know, given a phase III program, wanna take the time to make sure we're being a little nonspecific now, but it's all on track. Thank you. Our next question comes from Maury Raycroft with Jefferies. Your line is now live. Hi, thanks for taking my questions, and congrats on the progress. The phase I/ II longer-term commentary is helpful. Just clarifying, could we see the detailed phase I/ II data ahead of the phase III top line? It seems like you're seeing a clearer stat sig signal on MDRI in the phase I/ II. Based on the point improvement you mentioned for cognition, I'm wondering if you're seeing a stat sig p-value for cognition versus the natural history study data set. I think we've commented on the primary endpoint natural history comparison before in our powering analyses. I think we've said that we would be well powered. I think that's already sort of analysis. The MDRI is just extremely powerful method. I think it's the way forward for neurologic diseases. Your question you asked, will you see the detailed data? Probably not. I think we haven't set which science meeting the data will come out yet. I would assume it'd be later in the year. We have often presented things at the FAST Conference, we haven't set at this point a plan for the phase II data. It's not necessarily ahead of phase III at this point. We wanted to put out a little bit of data now just to give people confidence about what's going on and just give you a sense of the magnitude and outcome and the fact that we're confident about how the drug looks and that it continues to show good safety and the kind of cognitive benefit and MDRI benefit that gives us confidence in the design and what we're conducting in phase III. Got it. That's helpful. Maybe one other question. Just wondering if prior to the database lock and stats plan, do you have to have any discussions with FDA on magnitude of improvement on the primary endpoints, or is it just showing a statistical benefit? Is that sufficient? Yeah. There's no regulatory step between us and unblinding at this point. We're all agreed. There is no defined required minimally change for the Bayley. I think that is something that we don't need in the design. It's a continuous variable. However, we will always have what is known as a critically, you know, clinically important change of five points. We'll always look at data that way. The powering of the primary endpoint for Bayley cognition is based on a continuous analysis, which is really the appropriate thing to do. If you look at the numbers we just told you, 10, that is, you know, almost twice the minimally important difference already. I think we're at a pretty good place. Got it. Thanks for taking my questions. Our next question comes from Anupam Rama with JPMorgan. Your line is now live. Hey, guys. This is Joy on for Anupam. Thanks for taking our question. Maybe just one on the two upcoming gene therapy launches, DTX401 and UX111 in the back half of the year. Could you just discuss where you are in terms of commercial manufacturing and product scale-up and just your overall readiness from a CMC launch perspective? Thanks so much. Good question. I think we've been manufacturing actually since last year. For DTX401, the drug subs and drug product are both made at the plant in Bedford. For UX111, we have a contract manufacturer that's making drug substance in Ohio, and we're finishing the fill finish in our Bedford plant. We've been running runs last year and this year, and that's part of our expenses that we're spending money on is actually building inventory, and that's been going well. We're building inventory and feel like we should be in a reasonable position at the time of launch at this point. I think we're ready. I think the launch teams have been working on their work. I think the two PDUFA dates are quite close to each other, but the doctors we're going to are actually the same doctors. There's certain synergy that will happen by having the same. Most of the centers will be doing both products. Some may do one or the other. The quality treatment centers are getting set up, contracts in place. I think the synergy with having two of them will be real, and we're excited about the possibility. Of course, we still need to get approval, but at this point, from both manufacturing and commercial standpoint, we're set up and moving forward and excited about the prospects of launching two gene therapy products. Great. Thank you. Our next question is from Ellie Merle with Barclays Bank. Your line is now live. Hey, guys. Thanks so much for taking the question. Just can you give us any more color on how we should think about the timelines for getting data from the Aurora study? If the data are positive in the phase III Aspire trial, how are you thinking about what your base case will be for the ages in a potential Angelman label and if this will include adults? Thanks so much. Thank you. Aurora is how we're going to expand the label to other genotypes and ages. The main Aspire study is four to 17, all deletion. We have a younger group, the older group, and the other genotypes involved in Aurora. The study is still continuing to enroll and enrolling well, but it's also an international study, and we'll continue to collect data. We'll have some data at that time. We haven't really said through anything about how we'd approach our filing launch at this point in time. We're going to wait and see what the data look like and put together our plans. The study with Aurora, though, is still more enrollment to do. Great. Thanks. Our next question comes from Yaron Werber with TD Securities. Your line is now live. Hi, everyone. This is Steven on for Yaron. Thanks for taking my question, and really appreciate the color on Angelman. You mentioned the 14 mig was generally the maintenance dose being used. Can you give us some color on, you know, whether there might be more than one dose being used, why that might be happening, and whether there could be more than one maintenance dose in the label? Secondly, in terms of profitability projections, given that PRVs are selling for, you know, substantially over $100 million at this point, any color on what you're modeling in terms of PRV monetization and whether we can expect that full year 2027 profitability to be sustainable? Thanks. Okay. Well, I'll touch on the dose at high level. I don't know if Eric has anything more to add. I'll let Howard deal with the PRVs and profitability question. The vast majority of patients are 14, and from the main trial, the protocol actually in Aspire brings them to 14 in terms of how it's done. There are some patients that certainly been on drug for longer periods of time in various regimens. I don't know if there's anything else to add. I think it's a very high fraction around 14. Yeah. That is what we expect to label on. We expect, you know, a maintenance dose of 14 milligrams every three months. You know, once we get into commercialized setting, we have our DMP, we can explore, you know, potentially different dosing. You know, maybe some patients would benefit from every two months, some could benefit from a higher dose there too. Our plan is to, you know, prior to, you know, after discussions with the FDA, with a 14-milligram maintenance dose. That's really the main source of what's you're gonna see. Howard? With regard to the PRV, you know, we watch this with interest to see how they've been selling. As part of our plans, we have two PRVs we plan to monetize, one for UX111 and one for DTX401. You know, I think we've stated in the past that we've baked it into our model at a little over $100 million each, so anything above that would be upside. Of course, there's also an opportunity for a PRV with GTX-102, which would also be upside to our model. That's how we're thinking about monetization. I think you'd also asked the question about sustainability of profitability post 2027. You know, our plan is to not just hang out at the razor's edge, but to continue to grow profitability. Depending on the launches we have and their success, we'll figure out how much we can reinvest back into the pipeline versus drop to the bottom line. That'll be a fun conversation to have in due course. Sounds like it. Thanks very much. Our next question comes from Salveen Richter with Goldman Sachs. Good afternoon. Thanks for taking my question. Ahead of the phase III Angelman's data in the second half, can you speak to the path forward in the event that MDRI hits, but Bayley-4 doesn't? Thank you. I think as Eric noted today in the script is that we still consider that a positive study. That is we have essentially two ways to succeed, that Bayley cog can succeed, and the MDRI is provides maybe a more robust option. We negotiate this position with the FDA, I think while their tendency is to stick with single primary endpoints as their approach, we think the MDRI is actually a smarter and better way to go for neurodegenerative diseases. This is an opportunity to move in that direction. Our expectation is, as Eric had said, that a missed Bayley-4 but a positive MDRI is still a demonstration of efficacy in the program. Obviously, that would assume that, let's say, Bayley cognition just missed and then MDRI hit. You know, that would be a one potential scenario. We would not expect, for example, Bayley cognition to go negative and then have an MDRI positive and have that work out. The question really be, could Bayley miss for some reason, and MDRI provides an insurance policy and support for efficacy in the product that's broader than just cognition. We feel like there's ways, it's two ways to win for the program. We're actually expecting both to hit. As you know, we can always miss in our best intentions in a randomized controlled trial. I think the combination of both gives us a higher chance of being positive regardless of what happens in the patients. Thanks. Let's move on to the next question. Our next question is from Kristen Klooster with Cantor Fitzgerald. Your line is now live. Hi, good afternoon. For this latest Angelman cut that you looked at for the phase I/II data, can you tell us how the one-year plus data is stacking for cohorts A and B relative to what you saw across different measures for cohorts four and Z, and whether that's further strengthened your position of the dosing regimen and techniques you took forward in phase III? Okay. Yeah. We've shown the cohort A and B before. I think the cohort A and B is continuing to behave. I would say is that, remember, that's the most of the patients. C and D is relatively few patients. It's really mostly A and B. I think what we're talking about is cohort A and B extending now through the full year, and that's the data we're talking about. It's really driven off of A and B. That A and B is, we think, is pretty comparable to what you're seeing in the phase III because the A and B was in all the international sites. That included the seven or eight countries that were also doing studies, including a high overlap with the sites that we're actually using. I think that the A and B cohort, which is the primary driver of the data we heard about today, is very replicable with regard to what we're doing in phase III, both from the sites, countries, and patient type. I think it is a good model. I think the data are, should be in line with what we expect in phase III. Thanks. Let's move on to the next question. Our next question comes from Maxwell Skor with Morgan Stanley. Your line is now live. Hello, this is Selena on for Max. On Angelman, could you describe the contribution of caregiver input to Bayley-4 cognition in the phase I/II and how that changes over time with the longer follow-up data? Thank you. Well, thank you for that very technical detailed question. I'm not sure everyone knew about caregiver input. Just to be clear, in the raw scores that we're using for the Bayley-4, the FDA does not want us to include caregiver input. All right? All the analysis has to be done by the psychologist tester, we are not including any caregiver input in the Bayley-4 primary endpoint per FDA request. Now, out of I'm forgetting the number. Is it 20 or 30 items or something? There's, like, a couple items where caregiver input, two or three, that can have an effect. When we look at raw scores with or without caregiver input, we don't think for Bayley-4 cognition there's significant issue. If you're doing the expressive Bayley, there's actually a lot more caregiver input potential. It might have more effect on the, I'm sorry, expressive communication than on cognition. It's only a couple, two or three things we haven't seen have an impact, but we are doing it without caregiver input in the phase III trial. Emil and Eric, I think the question was maybe more around the phase I/II data that we've talked about, if we were able to look at that without the caregiver input, and I don't think that's how the phase I/II was run. Yes, that's correct. For phase I, II, we did use caregiver input, and it was, you know, part of the conversation designing phase III that the FDA made that request. We actually performed the test both ways in phase III, but the primary endpoint does not use caregiver input. Right. That's important to eliminate bias, and that's true for both your actively treated and your control group. It's a reasonable request. We can analyze without those items. They will not have a meaningful impact. That's what I said, that if we drop them out, they do not impact it. Because there's only a couple items out of a very large number where it might be impacting, right? Okay. The situation is there's two or three items. If the caregiver says that they think they're developing, but the doctor doesn't see it, the psychiatrist don't see it, they could score a point or two. We're saying if you drop those out, it's still, it's fine in cognition. Our point would be that what we see in phase I/ II is, would be consistent with or without caregiver input, right? Does that answer the question, Josh? We're good? All right. Boy, we're getting deep on COAs. Let's go on to the next question. Our next question is from Jack Allen with Baird. Your line is now live. Taking the questions, congrats on the progress. I wanted to ask about what your expectations are as it relates to the sham performance in the Aspire study. I know there is a limited data set from Angelman, are there any other surrogate neurodevelopmental indications that you've looked at as it relates to sham performance? My other follow-up was on the profitability. Any comments you can make as it relates to what you need as it relates to success from the gene therapy programs in Angelman that's baked in for assumptions for profitability. Do you account for those in the profitability guidance, or is it just the current base business? Well, I'll let Howard deal with the profitability question, but let me deal with the sham performance. Well, obviously we would not expect sham to have an effect. We haven't looked at all possible studies, but certainly in our own, in Angelman, in the control studies we've seen, we haven't seen much change. I would say to you that when you're talking about the performance of development, these kids are not gonna have a placebo effect exactly, right? They're not thinking, 'Hey, I'm getting a treatment. I should be better.' They're not gonna think this way. They're not, they're not developmentally changing. By not having caregiver input, which is maybe why the FDA doesn't want it allows there to be a more objective assessment of what's happening. We're really saying, could they get better on their own without anything happening? What we're saying is that the deletion patients just don't. We're pretty comfortable the sham forms will not be important. I don't know that there's other developmental disorders that are comparable, maybe Rett syndrome or other types like that. At this point, we don't feel that the sham should be any different from a natural history, and the deletion patients are pretty stable in terms of their Bayley cognition scoring. They do not change much, and we're talking about less than one point a year. Whether it's a randomized trial or even natural history. At this point, we're comfortable with it, but I understand your point right now where we seem comfortable with it, and we have adequate power. Even if there was a higher background signal, we should have adequate power to overcome that with the treatment effect we expect. Jack, regarding profitability and launch success assumptions, right now what we've said for top line is that we assume continued double-digit growth from our current products, plus contribution from upcoming launches, which could include UX111, DTX401, GTX-102. We haven't said much more than that, maybe what I can say is that it certainly doesn't require all of them to be successful for us to get to profitability. We have different levers we can pull to make sure we can live up to our promise of 2027 path to profitability. Great. Thanks so much for the color. Our next question comes from Ben Burnett with Wells Fargo. Your line is now live. Great. Thanks very much. I wanted to ask about the GTX-102 program, and great to hear about the long-term long-term data. I think you mentioned there were 66 patients in the long-term extension. Could you comment on sort of the reasons for discontinuations? Then I have a follow-up. Sure. Yeah, we can do that. It's actually been a little here, a little there, but it's mostly often in the beginning. Maybe you can comment on that, Eric, for them. Yeah. Very consistently, it was all due to burden of study participation. I mean, we do need to remember that some of these patients live very far away from treatment sites, and it does become a burden for these families. That was across the board the reason for those discontinuations, study burden. It sometimes happened kind of early, too, because some people realized they just couldn't do it. Yeah. It wasn't safety related. Okay. Thank you. The other question I just want to ask is just around CRYSVITA. Appreciate kind of the commentary you gave on the call just around some of the variability around sort of ordering patterns. I guess the question is sort of what visibility do you have kind of going forward through the next couple of months and sort of what gives you sort of the confidence in kind of the yearly guidance number for CRYSVITA? I'll let Eric comment a little bit because Erik's very close to the team at carrying on what's going on. One other element of this is that every year we're gonna have one other factor, which is the way the royalty is in the first part of the year, it's a little bit lower, then it crosses the threshold and it goes up. Whatever revenue is coming, our percentage goes up as the year goes on, and that's why the quarterly revenue goes up as well. It's just an ordering pattern thing, and there's gonna be this continuous ramp-up of our percent in the royalty stream. It's just gonna reset every year and crawl back up. Erik, what gives you confidence in CRYSVITA going forward in the North American territory? Yeah, no, it's quite simple. We're very confident in the underlying demand that we continue to see with finding patients and patients wanting to get treated across our regions, which is why we reaffirmed our guidance. Consistent with prior years, we expect the same sawtooth pattern that we've seen previously with, you know, lower Q1 and a rebounding Q2 and softer Q3 and a strong Q4. We expect, you know, as we have in previous years, to continue to deliver on our commitment to the street. Yeah. I think the thing that we would see in Q1, though, is like the start forms. What's the start? That's the demand you talked about. Continuations and so forth. Demand is strong in CRYSVITA. It's a great product. People stay on it when they get on it, and they continue to grow it, and we're here to support them and do our own work where we're commercializing. CRYSVITA has continued to grow and do well, and we just have to understand there's always this quarterly plan that's gonna happen almost the same every year. We feel comfortable how the year will go. Okay. Thank you for the color. Our next question comes from Yigal Nochomovitz with Citigroup. Please, your line is now live. Hi. Great. Thanks for taking the question. I was curious about the long-term extension data. You, you mentioned that you've seen the positive improvements in multiple domains and patients are continuing to improve developmentally. I'm just wondering how you assess those metrics with respect to sufficient powering on the endpoint for the Aspire trial for the Bayley-4 cognition. Do those observations in the long-term extension study on development improvement give you confidence that the powering on the Bayley-4 is sufficient for the Aspire trial? What would be the clinically meaningful delta that you'd wanna see on Bayley-4? Yes, Yigal. Thanks for the question. I think Eric just talked about hitting around 10 points, let's say, in the one-year time frame. That's the part of the A and B cohort and the others together that has, you know, gotten to the one-year mark. Some people are at the three-five-year mark. What we're saying is that one year they're hitting a number which is pretty close to what we've been expecting the whole time, and that size shows we're statistically powered. It's well above the MID at one year. We're feeling comfortable at that size. By the way, most people that know that, just that test are shocked at how much change there is because it usually doesn't move at all for most people who are expert, including Kim Goodspeed, who's our physician, who's a developmental specialist. She says you just don't see this thing move. 10 points is a big number. What we're saying and the way Eric put forth is that when you continue to follow these kids over the longer haul, they continue to go up in Bayley cognition. That kind of tells us that the patients are having a sustained benefit of the ASO on their function in their brain, and they're continuing to gain ground. That, to me, is really important. That's what the long term is telling you. I think phase III, of course, is very important for getting file approval. What is the commercial potential of a product? I think the long-term safety, chronic treatment, and continuing to gain ground tells you this is a treatment that has the ability to help kids over long periods of time in the post-market setting. With phase III in hand, being able to get to a commercial setting, I think this gives us more confidence that the potential of the drug to be a long-term benefit for patients with Angelman syndrome. Okay. Thanks. One on UX-111. Since the resubmission, have you had any other requests for information since the acceptance in April or any other inspection requirements, post acceptance of the BLA? Yeah. Well, we're having what I would call routine discussion with the agency. We normally don't discuss the details of those. We've had what I would call routine discussions on the BLA. Those continue. At this point, we feel that business is normal moving forward. We won't really comment in detail about it until something, a decision gets made. Okay. We're excited about the potential of that program. We're planning for a launch, assuming we get approval. Thanks. Our next question comes from Gavin Clark-Gartner with Evercore. Your line is now live. Hello, this is Yi Xiong for Gavin. Thanks for taking our question. Two from us. One is for Angelman MDRI endpoint. Just for clarification for the stat analysis. What is the delta versus the sham control is actually defined? Is the difference in the medium net response between the two arms or the difference in the proportion of the patients that are achieving a net response in at least one domain? Secondly, we have question about 106 in GNE myopathy, which we saw recently got IND clearance. Wondering, what is the key difference between this new molecule versus previous one that looks like also run through the same indication that failed in the phase III? What are some key takeaways we can learn from that history study to inform the current trial design? Thank you. Sure. Thanks. For the MDRI, what we're looking at is net domain improvement. Each patient will have a number of domains that they hit, right? We look at net domain improvement comparing the distribution curve of the treated patients to the distribution curve of the control patients, right? It's a net domain improvement. How many positive wins per patient do you see? We've shown before that we had often two domains or more on average per patient around that, in that range. Those domains can be variable. There can be various combinations. There are some patients that had as many as four or five domains of improvement. We'll look at those distribution curves for the net domains per patient. All right? That's the statistical comparison. For the GNE myopathy, I've been involved with that program from the very beginning. It's a horrible muscle disease. We think maybe around 10,000 patients out there, and we think it's a very chronic and terrible disease. The original molecule of sialic acid replacement didn't work as well because the sialic acid just didn't penetrate. What the new drug is a prodrug, one that we designed it, that has enhanced hydrophobicity that helps target uptake into muscle and gets released and transported by a sialic acid transporter. It allows it to get taken up into the lysosome and cleared across the lysosomal membrane into the muscle. That improved hydrophobicity mechanism will allow us to, in the animals or in dogs, to deliver large amounts of sialic acid to the cells substantially better than the other molecule, like many fold better. We think the potency is just dramatically better, and that puts us in a better position to actually achieve the replacement therapy that's required. We know from the prior work, and particularly the biopsy work, that these patients have an 85% depletion of sialic acid in their muscle. This drug should take us back to complete replacement, if not above replacement levels of sialic acid. We have greater hope this can be an effective drug for GNE myopathy. It's a program I should point out. It's funded through a venture philanthropy agreement with the patient group and who are very interested in the product moving forward. We were able to do that even under our financial constraints with the fact that they were funding it. They're funding us through the phase II proof of concept, which is allowing this program to move forward at this point in time. Thank you. Our next question comes from Luca Issi with RBC Capital Markets. Your line is now live. Oh, great. Yeah, thanks so much. Thanks for my question. Congrats on the progress. Maybe Emil and Eric, circling back on a couple prior questions. What is your relative level of conviction on Bayley score cognition versus MDRI? It feels to me that during the call, you came across as incrementally more positive on MDRI versus Bayley score cognition. One, would that be fair? Two, if so, can you still amend the protocol to potentially reallocate more alpha to the MDRI versus the Bayley score cognition? Again, any call there, much appreciated. Then maybe super quickly, on OI, I did not see anything in the press release or in prepared remarks. Should we assume that you have discontinued that program? Thanks so much. That we've discontinued OI. Oh, I see. Missed it. The MDRI is a more powerful measure. It has five endpoints in it. They gain power from all those endpoints. It is a very powerful way. We've been promoting it. We used it in our MEPSEVII program. It's just new for regulators. At this point, in our agreement with regulators, we've put 80% of the power into the Bayley-4, which is actually where you need the power because it's a sort of smaller magnitude effect. The MDRI hits very strong statistical significance. You don't really need more alpha assigned MDRI, even if you have higher confidence in it, because it's tremendous amount of power in it. I think what we've done is the appropriate proportion, and we don't really need to shift it more. The OI, we continue to do evaluations and discussion. We put a little bit in the release on this. We'll inform the Street when we have a decision what we're doing. We did not discontinue the program. It continues at the moment until we complete and get answers to key questions and make a determination. Got it. Thanks so much. Our last question comes from Raghuram Selvaraju with H.C. Wainwright. Your line is now live. Hey, thank you for taking our question. This is Ahmed for Ram. Just have a question about the PDUFA dates coming up in the second half of 2026. Can you frame the cadence of the commercial rollout and when to expect a meaningful revenue from both UX111 and DTX401? The second question is on the GTX-102 in Angelman. You mentioned discontinuation rates due to non-safety burden. Are you preparing any way to reduce discontinuation rates in a commercial setting, or do you not foresee that being an issue? Thank you. Sure. Obviously, launch of gene therapy is complicated, the reimbursement part of it and so forth. We're not guiding on any revenue, what the revenue would be for this year, we're certainly planning to move forward on getting the launch together. I'm sure Eric could go through this in great detail. I'll just summarize for you, Eric. That there'll be obviously various policies at launch we'll have to manage, eventually We are talking to payers in appropriate meetings now to help lay pipe for the planning process for that. The reimbursement will be some of the process, we'll have to work through and get patients treated. Our expectation is that there will be some time from PDUFA date to be able to get things going. We're trying to work as hard to get it going within a few weeks and to see who, how we can get it going. We expect to have product available, and it's more a question of getting the commercial process going. I think the team's been working aggressively and getting all the pieces in place it would take, and I've been participating with them on some of the payer meetings that look at what the plan is, what the policies were, and how to navigate the process to get the best outcome for patients. For discontinuation rates, we actually find the discontinuation rate very limited. Actually, it's a really small sample. Usually the treatment effect the patients start seeing is so meaningful that, you know, that's something patient families are looking for their whole lives. We don't expect a big discontinuation rate. As we move forward in it, we will clearly need to manage the accessibility and convenience. This may involve, you know, bringing in a device to help make lumbar punctures easier. We're gonna do our best to make sure this is as burdenless as possible. I would say, too, that a randomized trial or any kind of clinical trial has way more burden than getting something clinically in terms of what you have to do. I think the amount of tests and stuff is a lot, and I think for an aging family, that was probably more of a factor. At this point, based on what we've seen, and we're not expecting discontinuation to be a big deal. We are also gonna do our best to take care of patients before there's an issue and give them the best patient experience we can in terms of a convenience for a treatment that involves an intrathecal delivery of an ASO. Thank you. We have reached the end of the question and answer session. I would now like to turn the call back to Joshua Higa for closing remarks. Thank you. This concludes today's call. If there are any additional questions, please contact us by phone or at ir@ultragenyx.com. Thank you for joining us. This concludes today's conference. You may disconnect your lines at this time, and we thank you for your participation.