Ultragenyx Pharmaceutical Inc at Barclays Global Healthcare Conference Summary

The following is excerpted from the question-and-answer section of the transcript.

Question: Gena Wang - Barclays - Analyst : <_ALACRA_META_ABSTRACT>So maybe before we dive into the specific questions, maybe very high level overview of Ultragenyx.

Question: Gena Wang - Barclays - Analyst : Great. So I will dive into the setrusumab in osteogenesis imperfecta, that's I think the investor key focus in the past months or years. So now after first interim, now everyone is waiting for the second interim so if I did my math correct, I think based on the clinicaltrials.gov, the last patient completed enrollment is May 1, to update at least in the clinicaltrials.gov. So I assume sometime in the late April or early May, the complete dosing. So 12 months follow-up that will be the second interim. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 11, 2025 / 5:00PM, RARE.OQ - Ultragenyx Pharmaceutical Inc at Barclays Global Healthcare Conference So if I carefully correct, sometime around May, that should have at least the DSMB should know the second interim, whether it hits or not. So maybe walk us through the steps, how would they -- how soon would take DSMB to communicate with you and if it's negative or positive, how -- what will be the next steps you would take?

Question: Gena Wang - Barclays - Analyst : Okay. So maybe the several questions here. First, like I know the senior leadership do not see the blinded events, right? Does any clinical team within the company see the blinded events.

Question: Gena Wang - Barclays - Analyst : Okay. And then is it fair to say if the second interim did not hit, you would know the results quicker since you do not need to do additional analysis. And will you share with like how long it would take for you to share with the investors. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 11, 2025 / 5:00PM, RARE.OQ - Ultragenyx Pharmaceutical Inc at Barclays Global Healthcare Conference

Question: Gena Wang - Barclays - Analyst : Okay. So basically, a few weeks. Right. Okay, good. And then if hit, of course, you will not announce anything, but will you share both Cosmic and Orbit together with us?

Question: Gena Wang - Barclays - Analyst : Okay. So I just want to make sure I understand. So that if it's positive, you only share initially top line Orbit data and then do you need to do some -- like usually, how long does it take to at least clean up some of the data and you'll be able to share the top line, like you hit the stats or a p-value or the magnitude...

Question: Gena Wang - Barclays - Analyst : Okay. Okay. So basically a similar time line.

Question: Gena Wang - Barclays - Analyst : Okay. So now going back to your stats assumption. I think if I look at the earlier statements, the baseline AFR is about 0.72 and you power 80% to detect 50% benefit. And by the way, I did have some investor pushback or why you're powering like compared to your Angelman program, your powering assumption is much higher 90% and the magnitude benefit also is higher here why the powering was a little bit weaker compared to the Angelman. So there was some pushback. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 11, 2025 / 5:00PM, RARE.OQ - Ultragenyx Pharmaceutical Inc at Barclays Global Healthcare Conference Would that be -- for me, the first question is, so far, patient, do you see, at least from the baseline perspective, is that consistent with your powering assumption? And then what makes you feel confident this powering assumption will be sufficient. You'll be able to -- with current study that will be sufficiently powered.

Question: Gena Wang - Barclays - Analyst : Regarding the 67% reduction, right, that's the median and then now the study is a mean. What was the mean reduction for that Phase II study?

Question: Gena Wang - Barclays - Analyst : Okay. Good. And I do have investors basically proposing why giving yourself unnecessary volatility putting first interim, second interim, why not just go through the final, given you have a very high probability hitting the stats for the final. So maybe thoughts there. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 11, 2025 / 5:00PM, RARE.OQ - Ultragenyx Pharmaceutical Inc at Barclays Global Healthcare Conference

Question: Gena Wang - Barclays - Analyst : Okay. And then another question is that if you miss second interim and what will make you feel confident and you will hit a final and then the magnitude could be more than 50%.

Question: Gena Wang - Barclays - Analyst : Do you know the patient on baseline bisphosphonate, any rough idea what percentage of patients were on baseline bisphosphonate they had to win off.

Question: Gena Wang - Barclays - Analyst : So was that the majority of the patients were you talking about like 70% patient or --

Question: Gena Wang - Barclays - Analyst : Okay. So like 80%, 90%. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 11, 2025 / 5:00PM, RARE.OQ - Ultragenyx Pharmaceutical Inc at Barclays Global Healthcare Conference

Question: Gena Wang - Barclays - Analyst : I see. Okay. Okay. I think that's helpful to minimize the placebo noise there and also the fracture rate could increase for the placebo, right? Okay. Great. And Cosmic study, what is the assumption for the bisphosphonate arm the fracture rate?

Question: Gena Wang - Barclays - Analyst : Okay. Very helpful. So maybe we switch gear on the Angelman program. So maybe I started with the primary endpoint. In the past, we saw different endpoint, right? I think for the first time, we saw the Bayley-4 full cognition raw score in the past always the GSV score. So normalized the scores. So maybe tell us the differences between these two? And then what are the total raw score for the cognitive measurement?

Question: Gena Wang - Barclays - Analyst : So if I do a quick calculation, the total store could be 162, correct. Okay. And then when we look at the differences, you did show the natural history study. I think it was natural history two. When I look at the patient population, actually relatively small so maybe like I think in natural history to only 16 patients, we did see the raw scores of 1.2 and a standard deviation 9.5. So how confident you are with now the enrollment with the Phase III studies, you think that, that could be replicated?

Question: Gena Wang - Barclays - Analyst : I'll be good. So when we look back the GSV scores, when you're including Cohort 4 to 7 and A and B, we did see like there's a meaningful decline regarding the pool data, 6.7. We went back Cohort 4 to 7, that was 9.5 score roughly. And so which means A and B may be only 5-point something scores maybe what could be the reason leading to that differences regarding the cohort A and B.

Question: Gena Wang - Barclays - Analyst : Right.

Question: Gena Wang - Barclays - Analyst : Okay. Very good. And then for the enrollment, you already dosed the first patient last December. Any thoughts how is the enrollment ongoing? And do you try to involve as many as possible before Ionis start the Angelman.

Question: Gena Wang - Barclays - Analyst : Okay. Good. What is your internal plan, like estimate regarding the timing to complete enrollment?

Question: Gena Wang - Barclays - Analyst : Any quick update regarding the oral Phase II/III study?

Question: Gena Wang - Barclays - Analyst : Okay. Good. We have less than two minutes maybe quickly high-level update regarding the MPS IIIA, GSDIa and Wilson.

Question: Gena Wang - Barclays - Analyst : Wilson.

Question: Gena Wang - Barclays - Analyst : Great. Well, thank you very much. We look forward to the data update later this year.