Good morning, ladies and gentlemen, and welcome to Scholar Rock's call to discuss the U.S. approval of ISEMBYLD. At this time, all lines are in a listen-only mode. Following the presentation, we will conduct a question-and-answer session. To ask a question during the session, you will need to press star one one on your telephone. You will then hear an automated message advising that your hand is raised. This call is being recorded today on Monday, September 14, 2026. I would now like to turn the conference over to the Scholar Rock team. Please go ahead.
Good morning. I'm Laura Ekas, Vice President, Investor Relations at Scholar Rock. With me today are David Hallal, Chairman and Chief Executive Officer, Akshay Vaishnaw, President of R&D, Keith Woods, Chief Operating Officer, and Vikas Sinha, Chief Financial Officer. Before we begin, I'd like to remind you that during this call, we will be making various statements about Scholar Rock's expectations, plans, and prospects that constitute forward-looking statements for the purposes of the safe harbor provisions under the Private Securities Litigation Reform Act of 1995. Any forward-looking statements represent our views only as of today and should not be relied upon as representing our views as of any future date. I encourage you to go to the Investors and Media section of our website for our most up-to-date SEC statements and filings. With that, I'd like to turn the call over to David. David?
Thank you, Laura, and good morning. Thank you all for joining us for what is an extraordinary day for the SMA community. On Friday, we reached a defining milestone, the FDA approval of ISEMBYLD, our novel, highly innovative myostatin inhibitor that is now the world's first and only muscle-targeted therapy for children and adults living with SMA. Over the past decade, SMN-targeted therapies have brought needed innovation to the SMA community by improving motor neuron health. Yet significant unmet need remained as treatment for muscle, the principal organ clinically affected by SMA had gone unaddressed. With the FDA approval of ISEMBYLD, we are now ushering in the next phase of innovation in SMA treatment, bringing the first and only therapy designed to directly target muscle to the SMA community and creating new possibilities for patients and families. I would note three important points with respect to this landmark FDA approval.
First, ISEMBYLD is indicated for all patients with SMA two years of age and older who are currently receiving an SMN2-targeted treatment. This broad label enables us to serve a significant population within the SMA community and advances our ambition that any patient who can benefit from ISEMBYLD should have access to ISEMBYLD. Second, the label reflects the compelling clinical benefits that ISEMBYLD can bring to children and adults with SMA. For patients receiving a chronic SMN2-targeted treatment in our global randomized double-blind, placebo-controlled phase III SAPPHIRE study, ISEMBYLD changed the progression of SMA from a loss of motor function to a gain of motor function. Specifically, at the recommended dose of 10 mg per kilogram, ISEMBYLD delivered a robust, clinically meaningful 2.2 point improvement in motor function compared with patients receiving an SMN2-targeted treatment alone, as measured by the gold standard Hammersmith Functional Motor Scale-Expanded.
Akshay will provide much more detail on the ISEMBYLD label and clinical data shortly. Finally, we are thrilled that our U.S. launch of ISEMBYLD is now underway. Our highly experienced U.S. team has worked with urgency on extensive disease education and awareness initiatives that have advanced the understanding of SMA as a disease of both the motor neuron and the muscle. Supported by a broad label, compelling efficacy, and a well-characterized safety profile, we are exceptionally well-positioned for a successful U.S. launch. We are poised to redefine the standard of care for people living with SMA as we begin to serve a steady and consistent number of new patients through the initial phase of the launch and for many years to come. Scholar Rock is operating from a position of strength as we enter a new chapter as a commercial organization.
From a financial perspective, we exited the second quarter with $492 million in cash equivalents, and marketable securities. Also, with access to an additional $150 million from our debt facility, a priority review voucher that we intend to monetize, and revenues that will now commence and grow, we are well positioned to fund our growth initiatives. They include the ISEMBYLD launch in the U.S., our global expansion to reach patients in Europe, Japan, and up to 50 countries around the world, and advance our robust clinical pipeline and innovative platform. With this strong balance sheet, we do not intend to raise cash through an equity offering at this time.
Looking forward, now that our U.S. launch has commenced, our opportunity with ISEMBYLD and SMA alone represents many years of sustainable growth as we begin to serve the estimated 35,000 people with SMA globally who are receiving an SMN- targeted treatment. We are on our way to becoming the next global biotech powerhouse supported by bold science, innovative therapies, fully integrated global capabilities, and exceptional talent. Before I turn the call over to Akshay to further discuss the approval of ISEMBYLD, I want to express my gratitude to the FDA for their constructive and collaborative engagement throughout the review process, which helped bring us to this important moment. With that, I will turn the call over to Akshay. Akshay?
Thank you, David. I am delighted to be sharing news of the ISEMBYLD FDA approval with all of you today. This is a momentous milestone for Scholar Rock. After nearly 30 years of failed efforts across the industry to drug myostatin, today, we are the first company to successfully develop and secure FDA approval for a myostatin inhibitor. With that, let me share details of the comprehensive clinical program that supported the ISEMBYLD approval and the resulting FDA-issued label. SMA is a rare severe neuromuscular disease resulting in irreversible loss of motor neurons and progressive muscle wasting, leading to motor function decline. Patients experience muscle wasting that impacts all aspects of mobility and daily life, including basic functions like breathing, eating, dressing, self-care, and walking. Affected children often require significant support, and for many, independent living in adulthood can be very challenging.
Despite progress over the last decade with SMN-targeted treatments, SMA remains a devastating disease for too many children, adults, and their families. The motor unit has two key components, motor neuron and muscle. Given that motor function depends not only on neuronal signaling but also on muscle responsiveness, approaches that target muscle from the start have been urgently needed. With that, let me share details of the comprehensive clinical program that supported the ISEMBYLD approval and the resulting FDA-issued label. We developed a rigorous program to study apitegromab, now known as ISEMBYLD, in children and adults living with SMA. This program includes our global randomized double-blind, placebo-controlled phase III SAPPHIRE study. In the positive SAPPHIRE study, we definitively demonstrated that in SMA patients on chronic background SMN2-targeted treatment, ISEMBYLD showed a gain in motor function, while placebo was associated with a loss in motor function.
The SAPPHIRE study also demonstrated that ISEMBYLD had a well-characterized safety profile. Turning now to the label, ISEMBYLD is indicated for the treatment of SMA in adults and children over two years who are currently receiving an SMN2-targeted treatment. The recommended dose is 10 mg per kilogram IV, administered every four weeks. At this dose, ISEMBYLD led to a robust, clinically meaningful improvement in motor function. Specifically, compared to patients on an SMN2-targeted treatment alone, ISEMBYLD demonstrated a 2.2-point improvement at one year with a nominal P value of 0.0121, as measured by the gold standard Hammersmith Functional Motor Scale-Expanded. Importantly, 34.2% of patients receiving ISEMBYLD showed a 3-point or greater increase in the Hammersmith scale compared to 13.5% of patients on placebo at one year. ISEMBYLD-treated patients were more than twice as likely as placebo-treated patients to demonstrate a clinically meaningful improvement, 34.2% versus 13.5%.
Indeed, they are almost three times as likely as placebo-treated patients to reach this level of motor function improvement. To support the long-term safety, tolerability, and clinical benefit of ISEMBYLD, a total of 246 SMA patients have been studied in our clinical program, and we have over 900 patient-years of data. The safety and tolerability of ISEMBYLD in children and adults with SMA is highlighted in this table. Underscoring that safety profile, a total of 99% of patients from the phase II TOPAZ study and the phase III SAPPHIRE study entered the ONYX long-term extension study, and 93% of those participants currently remain in the study, some for more than seven years. Taken together, these data demonstrate that ISEMBYLD, the first and only muscle-targeted therapy for SMA, can deliver compelling benefits for children and adults with this disease.
The FDA approval of ISEMBYLD is an enormous milestone for the SMA community and for Scholar Rock. Before I hand the call over to Keith, I too want to take a moment to thank the patients, the families, and the clinical colleagues around the world whose support and commitment enabled ISEMBYLD to be developed. I would also like to recognize the Scholar Rock team, and in particular, my R&D colleagues and manufacturing colleagues who pursued a bold scientific vision with unwavering focus and determination, accomplishing something that has eluded the field for decades. My sincere congratulations to our team. At this point, I will turn the call over to Keith to discuss our U.S. launch. Keith?
Thanks, Akshay. I am very pleased to report that we commenced the launch of ISEMBYLD immediately upon Friday's approval.
We are thrilled to be serving the SMA community with this innovative, first-ever muscle-targeted therapy and now defining a new standard of care for patients living with SMA. As I've shared with you in the past, the vast majority of patients continue to experience persistent and progressive muscle atrophy that limits both function and independence despite receiving an SMN-targeted treatment. To this end, neurologists recognize that the future of treatment for patients with SMA is an approach that targets both the motor neuron and the muscle. Now, with the FDA approval of ISEMBYLD, we are ushering in the next phase of innovation where neurologists can do just that. For patients receiving chronic SMN2-targeted treatment, as demonstrated in the phase III SAPPHIRE trial, ISEMBYLD can change the progression of SMA from a loss of motor function to a gain of motor function, bringing life-transforming benefits to patients.
Our Scholar Rock team is now executing on what we know well and what we do well. Our exceptionally talented and experienced field team is ready to deliver ISEMBYLD. Over these past months, the team has been hard at work building and deepening relationships with the SMA community. Specifically, we continue to engage across the approximately 140 SMA treatment centers, 2,600 prescribing physicians, and their multidisciplinary care teams throughout the U.S. Now that ISEMBYLD is approved, we can execute on our plans, highlighting the compelling clinical benefits that ISEMBYLD can bring to the estimated 6,600 patients with SMA in the United States who are receiving an SMN2-targeted treatment. In terms of the launch, we expect a steady and consistent pace of ISEMBYLD patient starts as we work to serve a gradually increasing number of children and adults living with SMA.
As we begin the launch of ISEMBYLD, establishing a seamless, high-touch experience for patients and caregivers is a top priority. We have now launched our world-class patient support program, Scholar Rock Supports. The goal of this program is to provide robust, dedicated, long-term support for each and every patient and family throughout the ISEMBYLD treatment journey. Our Scholar Rock Supports program offers personalized, comprehensive services to patients and caregivers, including disease and treatment education, insurance navigation, infusion day logistics, caregiver support, and financial assistance for eligible patients. We expect that approximately 50% of ISEMBYLD patients will be insured by government payers and the remainder to be covered by commercial payers, and we are working collaboratively with them to establish broad and reliable access to ISEMBYLD with coverage that is consistent with our label. I would now like to provide information regarding the price of ISEMBYLD.
When establishing the price for ISEMBYLD, we considered several key factors, including the rarity of SMA, the severity of SMA, and the compelling clinical benefits of ISEMBYLD. First is the extreme rarity of SMA. As I mentioned earlier, there are only an estimated 6,600 patients in the United States who are receiving an SMN2-targeted treatment. Second is the severity of SMA, which is a devastating and progressive disease, and despite the use of chronic SMN-targeted treatments, over time, patients can plateau and decline, leading to ongoing motor function loss. Lastly is the compelling clinical benefits that ISEMBYLD brings to patients. As demonstrated in the positive phase III SAPPHIRE study, ISEMBYLD changed the progression of SMA from a loss of motor function to a gain of motor function, specifically compared to patients on an SMN2-targeted treatment alone.
ISEMBYLD demonstrated a greater than 2-point improvement in motor function at one year and were nearly three times as likely to reach a 3-point or greater increase in motor function. Based on the rarity and the severity of SMA and the compelling clinical benefits of ISEMBYLD, we expect the annual net cost in the U.S. for a typical patient to be approximately $310,000. This typical patient annual net cost takes into account the weight-based dosing in the ISEMBYLD label and the typical patient age and weight based on demographic data from Cure SMA, the single largest U.S. SMA registry. This typical annual net cost also takes into account expected compliance and mandatory government discounts. Of course, this annual net cost will vary based on the individual's weight and specific insurance coverage. The Wholesale Acquisition Cost or WAC of a single-use 150 mg 3 ml vial is $11,659.
While our team is in the field with healthcare providers, Scholar Rock Supports is enrolling initial patients and caregivers. I would like to provide an update on the commercial availability of ISEMBYLD. Vials have been on site at our third-party provider and are now being packaged and labeled. ISEMBYLD will be available for infusion within days. Patients can receive their ISEMBYLD infusions at centers of excellence, freestanding infusion centers, or in the patient's home through our home infusion network of more than 10,000 affiliated nurses nationwide. ISEMBYLD will be available through our specialty distributor and through our expanded specialty pharmacy network that is specifically designed to provide optionality for patients, caregivers, providers, and payers. Importantly, patients can access ISEMBYLD through that same specialty pharmacy where they currently receive their SMN2-targeted treatment.
In closing, we are very excited to be launching ISEMBYLD across the United States as we now begin to serve one patient, one caregiver, and one family at a time. It is our ambition that every patient who can benefit from ISEMBYLD should have access to ISEMBYLD. With that, I will turn it over to Vikas to provide a financial update.
Thank you, Keith. We are very proud of Friday's landmark approval of ISEMBYLD, and we are pleased that the U.S. launch is now underway. From a financial and operating perspective, we are in a very strong position. We exited June 2026 with $492 million in cash equivalents, and marketable securities. Looking forward, we have multiple non-dilutive options available to us to continue to strengthen our balance sheet. First, with this approval, we now have an additional $150 million available to us under our debt facility. Second, we are very pleased to have received a priority review voucher from the FDA, which we intend to monetize. Third, as a commercial-stage company, we will begin to recognize revenue from ISEMBYLD sales in the United States.
We are well-positioned to fund our ISEMBYLD launch in the U.S., our global expansion to reach patients in Europe, Japan, and up to 50 countries around the world, and advance our robust clinical pipeline and innovative platform. With this strong balance sheet, we do not intend to raise cash through an equity offering at this time. I would like to now provide additional details on the financials related to the U.S. launch of ISEMBYLD. As it relates to cost of goods, the current cost of inventory manufactured prior to FDA approval has already been expensed. For a period of time, cost of goods sold will primarily reflect expenses related to packaging, labeling, and other overhead costs. We then expect costs to ramp up to a steady state over time beyond 2027. Turning to the inventory at distributors.
While the first quarter of sales will reflect some level of inventory in the channel, we plan to keep levels at a minimum. We continue to operate with a tight financial plan, and our prioritized investments remain focused on our ISEMBYLD launch in the U.S., launch readiness in Europe and Japan, strengthening our supply chain to support our expanding pipeline and our anticipated growing global commercial demand for ISEMBYLD over time, and advancing our highly innovative clinical programs. With that, I would like to turn the call back to David. David?
Thanks, Vikas. Friday's FDA approval of ISEMBYLD, the world's first and only muscle-targeted therapy for children and adults with SMA, is a defining moment for the SMA community. This achievement reflects years of rigorous science, disciplined execution, and the perseverance of a Scholar Rock team that never lost sight of the patients and families we aim to serve. I would like to express my gratitude to our team, our clinical investigators, and our patient advocacy partners, including Cure SMA. Most importantly, I would like to thank the 246 patients and their families who participated in our SMA clinical trials. Their trust, dedication, and determination made this milestone possible and continue to inspire our team as we begin to serve the SMA community with this important first-in-class muscle-targeted therapy. We are incredibly proud of this milestone, but this is not the finish line. It is only the beginning.
As we now enter the next phase of innovation for the SMA community, we do so with a bold ambition to redefine what is possible for people living with SMA around the world, beginning today with children and adults in the United States. With that, we will now open the line for questions. Operator?
Thank you. Ladies and gentlemen, to ask a question at this time, you will need to press star one one on your telephone and wait for your name to be announced. Please stand by while we compile the Q&A roster. Our first question coming from the line of Eric Schmidt with Cantor Fitzgerald. Your line is now open.
Thank you, and good morning, guys. Congrats on the landmark approval and the broad ISEMBYLD label. Maybe for Keith, can you provide a little bit more detail on some of the assumptions behind the average age, weight, compliance, and discounts that direct you to that $310,000 per year price point. Then a follow-up, in terms of the ISEMBYLD label, obviously the safety looks clean overall, but I am hoping the team might address the language regarding fracture risk. Where is that coming from? Thank you.
Thanks very much, Eric. We will go to Keith first, and then Akshay will address the other item in the label regarding fractures. Keith?
Yeah. Thanks, David. Eric, thanks for the question. I guess the first thing that I want to acknowledge is we're very gratified that the agency, the FDA, recognized the important benefit that ISEMBYLD can bring to all adults and children two years of age and older with SMA, and that's reflected in this very broad label. As I mentioned in the prepared remarks, anytime we go to price a drug, we always consider the extreme rarity and the severity, along with the compelling clinical benefit that ISEMBYLD demonstrated in our phase III SAPPHIRE study. I want to first remind you that the wholesale acquisition cost of a vial of ISEMBYLD is $11,659.
Now, as we took a look at the single largest SMA database that exists in the United States, the Cure SMA registry, we found that a typical patient is expected to weigh in the 35 kg-45 kg range and would be infused with approximately three vials every four weeks. We've also assumed that a compliance rate of 85%-90%. Being dosed every four weeks, you could have where patients will miss one to maybe two doses per year. In addition, we factored in the mandatory government discounts. I mentioned before that the payer mix is roughly 50% commercial and 50% government pay, but we also have patients that will be treated in 340B facilities.
When you factor in all of these things, compliance and the mandatory discounts, the typical patient weight of 35 kg-45 kg, we're going to be at a net annual cost for a typical patient to be $310,000. But I do want to close with reminding you that this price is going to vary on a patient-by-patient basis based on that patient's weight and their insurance coverage. Thanks.
Great. Thanks, Keith. Akshay?
Yeah. Appreciate the question on the safety, Eric. So a couple of things. First of all, we are very proud of our well-characterized safety profile for apitegromab, based on several facts. 99% of patients from the phase II and phase III rolled into the ONYX long-term safety extension study. 93% of them are still on that study today, some out over seven years. All of that has generated 900 patient years of safety data, which leads to the conclusion that the drug is well-tolerated. As for the specifics of the fracture question, the literature rates for annualized incidence rates for fracture in this patient population range from 4% -1 4%. Indeed, the cumulative lifetime prevalence is up to 40%. So our numbers are well within the annual incidence rate, in actual fact.
I think we have to be mindful of the potential for the tyranny of small numbers here, with twice as many patients being on apitegromab in the phase III as on placebo. Obviously that can skew the amount of safety information you collect for both those groups. Just to illustrate the issue, no patients from the placebo arm who rolled onto active in the ONYX safety expansion study had a fracture at year one, versus if we look back at the SAPPHIRE phase III study, eight patients on active had a fracture at year one. So the fact that placebo patients going onto active drug, apitegromab at one year having none, shows you how these numbers can wobble around. Most important to me as a drug developer, I would say when patients did have a fracture, number one, events were all classified as not related.
So from their practice, the investigators appreciate background issues like osteoporosis and falls that were associated with the fracture events. They have seen them before many times. And B, all patients on study who had a fracture stayed on drug and the fractures resolved. Now I think that says something very important as well. Finally, I will close by saying that not a single patient was withdrawn from drug after a fracture or came off study, and that is across the entirety of the clinical development program and the expanded access use program. So I think that is saying something very important as well, and we are very comfortable with the go-ahead safety profile. Thank you.
Thank you. Our next question in queue coming from the line of Michael Yee with UBS. Your line is now open.
Great. Thank you. Congrats on the approval. It's been a long time coming, and it's been a great journey. Two questions. One, just on thinking about the commercial launch. I know that you said you want to keep inventory low and some things like that, but can you just talk about what type of metrics, what type of data points you will provide, and what type of leading indicators you can be able to talk about over the first one or two quarters? How we should be thinking about numbers of patients you think you can go after? I would think there's some bolus or other factors, but maybe you could talk about that over the next one, two, three quarters. Then just one detailed question about the fractures. Appreciate the comments you mentioned, but the label talks about specifically proximal type impact in mouse models.
Just wanted to understand whether the fractures that you saw in the clinical data sets were proximal or distal. That might be helpful, too. Thank you.
Thanks. Thanks very much, Mike. We're going to go to Keith on the launch dynamics and metrics, and then back to Akshay on the proximity. Keith?
Yeah. Thanks, David. Mike, thanks for the question. As we've had additional time to prepare for this launch, we've really built one of the best in the industry rare disease teams, in several different aspects. Whether it's the team that's out in the field or whether it's the business analytics team that's here in-house, I can tell you that, internally, we already have scorecards that are ready to go, and we have a number of metrics that we will be looking at here internally. At this time, here we are on day three, we haven't really made a decision on what type of metrics that we will commit to on earnings calls. Obviously, you know that we'll be reporting revenue, which will be the true north.
Might not be the true north in quarter one, because as you've heard me discuss before, when a patient gets prescribed a brand-new therapy in rare disease, that usually leads to prior authorization and many times followed by a denial. The revenue in quarter one, I just want to say, will have consistent and steady growth. Over time, we'll determine what other metrics that we will be bringing out. But obviously, covered lives and how well we're doing on getting policies that are developed, which are in the public domain anyway, I think will be a major factor, as well as how well our coverage is doing for our team, to where these 6,600 patients in the U.S. are currently being treated.
Thanks very much, Keith. Akshay?
Yeah. Mike, so in terms of the animal data, the non-clinical profile, obviously those are very exaggerated doses and the proximal fractures you mentioned. In the clinical situation, the program, there are distal fractures. In fact, the range of fractures seen in the program is completely within the range that practitioners see day to day in their practice with these patients who, as I said, 40% cumulative lifetime incidence of fractures, which is very sad for these patients. But of course, they have all these background concomitant factors like poor nutrition, osteoporosis, falls. Hopefully, as the standards of care continue to improve, those will diminish. But the fractures were distal, so not related to the preclinical profile.
Yeah, Mike, and we saw your note from yesterday, and in fact, as you indicated as a question, in SAPPHIRE, the three femur fractures were all distal.
Beautiful. Thank you.
Thanks.
Thank you. As a reminder, in order to accommodate all participants in the queue, please limit your question to only one question per person. Our next question in the queue coming from the line of Srikripa from Truist Securities. Your line is now open.
Hey, guys. Thank you so much for taking my question, and congratulations on the approval. I echo Mike, it's a long time coming, but great journey. I do just want to go back to the launch trajectory. When we think about it, what are the gating factors that we should be looking at? In terms of payer coverage and formularies, how quickly do you expect top commercial health plans and the state Medicaid programs to establish formal policies? Are you expecting any kind of prior auth hurdles at all? Thank you.
Thanks very much, Srikripa, and it's been great to be on this journey with you. As I think Keith and I have noted, with nearly all patients with SMA claiming that their number one need is more motor function and more muscle strength, and three-quarters of neurologists indicating that the optimal way to treat patients with SMA is by both addressing motor neuron health as well as the muscle, the principal organ clinically affected in the disease. We certainly are expecting some nice demand features in the launch. I think you adequately and appropriately focus a bit on the reimbursement and access side, which I think Keith has great confidence in over time, but those dynamics initially at launch are worth him walking through. I'll hand it over to Keith to comment on that. Keith?
Yeah. Thanks, David. Srikripa, I guess the first thing is I agree with David, and I think we've shared that in the extra time that we've had and been able to be out there, it does seem like the demand to utilize apitegromab has grown from a physician and patient perspective. I think I just saw a survey that came out last week that showed of 15 neurologists that were surveyed, that 62% of them believe 62% of their current patients are good candidates for apitegromab. And three-quarters of those physicians said that they could see themselves prescribing it within the first three to six months. I do think that the demand is going to be there.
With that being said, our market access team has already been meeting with not only the commercial payers but also government payers and working with Medicaid, so that we could discuss what a potential policy could look like. And our goal is to have these policies that will be in line with the label. As you know, we've got a very broad label here, so look forward to the ongoing discussions with the various payers, both private and public. With that being said, it typically takes a period of time for policies to get drafted and ultimately published. So what I do expect in this first six months, that we will be without a J-code. The good news is the timing of our approval. We're now only going to sit quarter four of this year and quarter one of next year with an unspecified J-code.
But with Scholar Rock Supports, we will be able to work through that period with an unspecified J-code. But it will take time to get these policies up and in place. I think the last thing I'll say is, I've given you this statistic before, but in the last launch that I participated in, even six months post-launch, the average time from prescription to actual infusion was still slightly over 60 days. And that's where I'm going to ask that we be a little bit patient here in these first couple of quarters as the policies get published, as the J-code comes on board, as hospital formularies put apitegromab on formulary, and then you'll see that time shorten from prescription to infusion. Ideally, we'll get that down into the 10 day-1 4 day period.
Thank you. Our next question in queue coming from the line of Cory Kasimov with Evercore ISI. Your line is now open.
Hey, good morning, guys. Thank you for taking the question. Let me add my congrats on this approval. My question, I want to go back to the safety front and kind of follow up here by asking, did the FDA require any sort of post-marketing requirements or commitments specifically on whether it's bone or reproductive safety, or is it sufficient that you kind of ongoing submit data from your ongoing open-label extension ONYX study on that front? Thank you.
Yeah, great question, Cory. Akshay?
Yeah, and the answer is relatively straightforward. So there are no post-marketing safety commitments with respect to the fractures on the reproductive side that you mentioned. And there'll be standard safety updates that obviously we'll be providing to the FDA.
Thank you. Our next question in queue coming from the line of Geoff Meacham with Citigroup. Your line is now open.
Hey, guys. Good morning. Congrats on the approval. This is Jarwei on for Geoff. Maybe just a quick question on the number of patients and percentage of them. Can you give us a sense of what percentage of eligible patients reside at centers that are ready to prescribe and infuse ISEMBYLD immediately versus ones at centers that maybe require a little bit more work and reach from your FTEs? Then maybe thinking about preparation, how are you preparing for demand if initial uptake exceeds expectations? Just given you mentioned you guys plan on keeping inventory in the channels as low as possible. Thank you.
Thanks, Jarwei. As I think Keith and I have been noting for some time, a little bit of the extra time has been really helpful for Keith's team, which has really been able to work very closely with the SMA community, the centers of excellence, the KOLs, also reach even deeper into the SMA community to understand care pathways and such. Keith can comment on all of those questions. Keith?
Yeah, thanks a lot. I guess the first thing that I want to call out here that's a definite advantage for us in a rare disease launch is that these patients are known because as our label states, they are already on an SMN2-targeted therapy. It's not about us being out there having to find the patients and have them diagnosed. They are already known.
The second thing that I would say is the 6,600 patients that are on an SMN2-targeted therapy around the U.S., they really are predominantly in those either 140 centers or they're consulted by somebody at those SMA expert centers. But the 2,600 neurologists that currently prescribe for them is the group that we are actively covering. I do feel good about the coverage that we're going to have in a timely manner because we have been establishing not just these relationships, but as David alluded to, it's even on a patient-by-patient basis on how they want us to participate. Enrolling that patient in Scholar Rock Supports will allow us to help with a number of different things, but that would also include infusion logistics. Okay? Your second question is, what if we get over-demand into the system?
I've got to tell you that I've got, I think, the best U.S. General Manager in the business in Rebecca McLeod. Rebecca also led the world-class VYVGART launch with me at argenx for myasthenia gravis. As you know, our demand had increased greatly there. Now she's only even more experienced after having done this with CIDP and subQ. The team has already built contingency and backup plans in the event that we do have this demand. We will be able to cover it at Scholar Rock Supports, and we will be able to cover it at our external hub. I really like the contingency plans that we've built, and I hope that we get to put them into action.
Thank you. Our next question in queue coming from the line of Tess Romero with JPMorgan. Your line is now open.
Hi, David and team. Congratulations to you and the entire team at Scholar Rock and to patients and their families. Just to double-click here on a prior question. As you think about ramp, is there a specific target or target you can tell us you would like to achieve, hopefully on new patient starts, payer coverage as you move ahead that may help guide us on how you're thinking about the trajectory here? I have a quick follow-up.
Okay. Thanks, Tess. Keith?
I guess first of all, we were not getting granular on numbers on what patient trajectory is and what we expect in the numbers. Obviously, this is something that, as I mentioned before, we will be monitoring on a daily basis, whether they come in through our Scholar Rock Supports programs or if they come in through one of the specialty pharmacies that are in our network. We will be receiving real-time data on this. I do see in the future, Tess, where we would be able to provide you percent of covered lives at some point. Ultimately, I expect, like you see with most rare diseases, that we're going to get that number up into the mid to high 80s of percent of covered lives.
If I look at the SMN2-targeted therapies right now, as you've heard me say before, it almost always requires a prior auth. When prescribed, 50% of them are denied. Out of those that are denied, they go through the appeal process, and you almost get 90%. It's about 87.5% of patients that get prescribed an SMN2-targeted therapy wind up being able to receive it. We see that we will be able to get into a similar range over time.
Tess, before your follow-up, I would just add that as I think both Keith and I noted earlier, we have great confidence in a steady and consistent addition of new patients quarter- on- quarter, year-on-year for many years to come, starting here in the U.S. and eventually launching in Europe, Japan, and up to 50 countries around the world. We think that it is that opportunity over the long run that we see positioning Scholar Rock for sustainable growth for many years to come. We think demand will front-run access, for sure. We're a little less concerned about ramp and much more confident in where we're heading in a very steady and consistent way, quarter-on-quarter, year-on-year for many years to come. Your follow-up question?
Great. Anything about your market research work that you would flag in terms of who you expect will be the earliest adopters? Thank you.
Yeah, it's a great question. That's the benefit of having such a broad label is one could see both from a patient and family perspective as well as a physician and healthcare team perspective, a variety of different approaches. Some may want those patients that have plateaued and are beginning to decline. Others may want earlier is better before muscle atrophy sets in, and one could really look to make sure that they get in front of any plateau or decline. I think we've seen in surveys a number of physicians, Keith, who indicate that all patients on an ongoing chronic SMN2 therapy are appropriate for treatment. They would want to be discussing the first and only muscle-targeted treatment now approved by the FDA with all of their patients. So I think it, very much like the label, it provides a lot of optionality for who's first.
But I think more importantly, we have great confidence that essentially anybody within label who can benefit from ISEMBYLD should have access to ISEMBYLD. I think Keith has established, along with Rebecca, a sensational team prepared to do just that.
Yeah, the only thing that I would add is that obviously we have the ONYX patients that are on our extension trial as well as our EAP patients. These will be the first patients that we'll be enrolling into the Scholar Rock Supports program, and that we will then be transitioning them over to commercial drug. What I do find is sites, physicians that have had experience with apitegromab, either through the clinical trial or through EAP, they are already the ones that have additional patients in mind that they would like to add to the drug. As we move forward with all of the other additional sites, we've got some that have patients that they have already identified and are ready to prescribe.
Then I think we have others that it's going to be a situation where probably the toughest patient that we will get will be their first one. Because I feel confident that after they have their first patient on apitegromab, and they get to, instead of reading the primary endpoint and secondary endpoints from a study, they're hearing from the patient, their real-world experience, and their quality of life and what's taking place in their life because of being able to now be on the first and only muscle-targeted therapy. I think that's what's going to help influence and expand. The last thing I'll say is, look, this is one of the tightest patient communities that I've ever worked in. So I think the word is going to spread amongst the patients as it has already. So I think that will help be a driver for us.
Great. Congratulations again.
Thanks, Tess.
Thank you. Our next question in queue, coming from the line of Evan Seigerman with BMO Capital Markets. Your line is now open.
Hi, guys. Thank you so much for taking my question, and congrats on the approval. With FDA approval in hand, what are the gating factors for a potential European approval? Do you expect that the inspections that were done for this facility should suffice whatever the European regulators need and their processes? Thank you.
Excellent question. Akshay?
Yeah. We have had an excellent dialogue throughout the MAA review with the CHMP, up to including the recent advice that we should withdraw. We will be refiling promptly, we believe, with the second fill-finish facility. They are well aware of that. They are very supportive of that. We are just working out the timelines around that. In fact, as soon as we get the green light, we are ready to refile. We feel like we are in a great spot, and everything done with the second fill-finish facility in terms of inspection, et cetera, by the FDA will support the ultimate CHMP approval.
While we have not necessarily provided guidance on when we are resubmitting and when we would expect or how long we would expect the review, largely with the alternative vialer to take, what we have indicated to you is the European regulators have gotten back from high holiday season. They will be getting back together. We should be learning in the coming period of time, a little bit more about that timeline, and then we will certainly update you all on those timelines.
Thank you. Our next question in queue coming from the line of Ali Bratzel with Piper Sandler. Your line is now open.
Hey, good morning, and a big congrats from me as well. Just a follow-up question to some of the prior discussion. Could you characterize awareness of apitegromab among patients and caregivers? Just to what extent do you expect prescribing will be patient-driven, by patients seeking out treatment versus prescriber-driven? Then just one quick follow-up on fractures. Do you expect that fracture warning language to affect patient selection or treatment discussions in patients with low bone density, prior fractures, or contractures? Thank you.
Yeah. Keith, we certainly know this is an incredibly important day for the SMA community, and we as a company have been engaging with patients and families for quite some time. We know how engaged they are and how active they are in their care plans with their physicians. I'll have Keith comment specifically on your question. Keith?
Yeah. Ali, since we do know that these patients are already on an SMN2-targeted therapy, their awareness in the community is quite high. The fact that this exists already, I would tell you that patient awareness is probably at one of the higher levels that I've seen in a rare disease launch. I also think that physicians are aware of the product, and very soon that it is now going to be available. I think last year when you had two CRLs for this community in SMA back-to-back, two days in a row, it even made that drive and desire for this more, and it certainly felt like that over the last 12 months.
As far as will the decision be driven by the patient or by the physician, look, at the end of the day, the physician is always the one that is in charge of prescribing for the patient. But let's not lose the importance that in this industry, we know that when a patient goes in and asks for a medication, it is the majority of the time, provided that the safety profile is compelling. There is less hesitation from a physician to be able to utilize that.
We do have a program that is called Life Takes Muscle, that we have had patients that have been enrolling in this program for now better than a year. We are able to make them aware that the product is now approved. So we are going to look at this from all sides, direct to patients, and obviously our work with the healthcare professionals.
Yeah. Ali, I will just comment on the second part of your question. As Akshay, I think, laid out in a lot of detail, the fact that 99% of all study participants rolled into our long-term extension ONYX study, 93% remain actively receiving apitegromab in that study, some for now more than seven years. Not a single patient in all of our clinical trial or early access experience has ever discontinued due to fractures. The fact that the incidence rate was well within that has been recorded in the literature between 4% and 14%, that there is no increase in fractures with more exposure to apitegromab. I think as Akshay laid out very nicely, even in the label where the placebo rate was 2%, those patients then rolled into ONYX, those placebo patients.
In their first year of receiving apitegromab, there were zero patients and zero incidents of fractures, which also sort of highlight, as he noted, sort of sometimes the law of small numbers. Look, I am glad it is in the label. I think everybody should have the awareness, and we are aligned with that. But I think that this is an experienced medical community and patient community that will be able to understand the compelling clinical benefits of ISEMBYLD, and as Akshay noted, the well-characterized safety profile over a seven-year, eight-year development program. So we are really looking forward and are happy we are out there now to bring apitegromab or ISEMBYLD to the broader SMA community.
I would just add there is no contraindication in hope. There is no expectation of any kind of bone scan to stop treatment.
Thank you. Our next question in the queue coming from the line of Gary Nachman with Canaccord Genuity. Your line is now open.
Great. Good morning, and my congrats as well on the approval and broad label. Within the patient support program, how much co-pay support will you be providing, especially until the reimbursement improves? How do you think that will impact the growth to net for the first few quarters of the launch on a relative basis when thinking about the $310,000 average annual net cost? That is first. Then secondly, just describe a bit more, Keith, just how the infusion network is set up, how robust it is, and if you think the monthly infusions could be a hurdle for certain patient groups, any of the patient groups whether it is by age or geography or ambulatory status. That will be important. Thanks.
Yeah. Thanks very much, Gary. I will hand it over to Keith, but I think when Keith was kind of as he noted, the typical patient at that price really was using understanding weight-based dosing, leveraging the largest database of its size, but also thinking about what percentage of infusions will be delivered to patients in a given year, and obviously with a 50% payer mix of government payers, understanding that there are some mandatory government discounts. I think that was all reflected in there, and Keith, I think you even assume that of any underinsured or uninsured patients in the patient assistance program. I do not think anything is off. I think that was really within the framework of what Keith had shared earlier. Keith, do you want to comment a bit on the infusion network?
Yeah. First of all, just on the first topic, I think that David has nailed that, and I really do not expect a GTN to be impacted by the outstanding assistance programs that we are going to be able to offer eligible patients through Scholar Rock Supports. It is going to be different types of programs that are eligible for them. It will be based on that individual's need on which of the programs that they can take us up on it. As far as the infusion network, look, I think that this is not only going to be driven by patient preference, but also by the facility's preference. I can tell you that in real-world practice, I have heard where they have a desire, our EAP, for example.
They do give the first couple of infusions typically at their center, and then if a patient chooses to be treated elsewhere, it is coordinated. Approximately 50% of our EAP patients right now are in fact on home infusion. We have been putting our network to the test a bit. As far as from a Scholar Rock point of view, we are agnostic. We are going to help them be treated wherever they would like to receive their infusion. Some people don't want somebody coming in their house, or their insurance might not allow them to have home health care. in that event, if they want, we will help them find an infusion center that is more convenient to their house, whether it is a freestanding infusion center or outpatient at a hospital, whatever is going to work best with them.
At the end of the day, a lot of products are given a lot more frequently than every four weeks IV. For devastating illnesses and severe unmet medical need that exists like it does here with SMA, I really don't think it is that substantial of a burden to basically take 13 hours out of a year to have this product infused.
We definitely think that's been borne out in all of the persistency rates for patients for all these years of the development program with 93% of patients remain on treatment over that period of time.
Thank you. Our next question in queue coming from the line of Ritu Baral with TD Cowen. Your line is now open.
Good morning, guys. Congratulations on a great day for SMA patients. I have a question on the EAP patients that you guys have mentioned a few times. Could you help EAP patients that you have, what their conversion rate may be, whether there is a bridging program or not in place? There was a comment, I want to make sure I understand this. There was a comment on where a patient is treated may be a factor in the launch curve. I wanted to just drill down a little further on the meaning of that. Is that a statement on sort of like the 140 SMA centers and tiering of these centers or experience of the treating clinicians? If you could elaborate what the where means, if you know what I mean.
Yeah. Thanks so much, Ritu. Keith?
Yeah. I would say first on the EAP patients and a conversion rate. Ritu, I do not have privy until approval of actually each of those patients and what their actual insurance coverage is. So right now it would be difficult for me to actually say, "Hey, we expect this level of a conversion rate in the program." These are going to be the first patients that are enrolling into Scholar Rock Supports, and they will be ones that we will be working on converting them just as quick as we possibly can. As far as a bridging program for them, it is not necessary at this point.
The reason being is because we can still keep them on clinical supply instead of commercial supply because we use the clinical supply at EAP, and we are going to allow them to continue to get infused on the EAP program until we have successfully converted them over to commercial. The one thing you mentioned on the launch curve, on where a patient gets treated as to how does that affect our potential launch curve. I would say the biggest impact is going to be when they are going to be getting that first couple of infusions within the hospital. I say that to you because most hospitals do not allow you to do a formulary process prior to a launch. So the formulary process will begin now to make the drug available within the hospital.
In some of these larger teaching institutions, this can be a couple few months delay for when they actually would have the product in-house to be available. That's something that the demand could be there ready to utilize it, but they have to be able to purchase the product at the hospital in that situation. Understood. How many U.S. EAP patients are there? We've never really given that number publicly on the exact number of EAP patients. I will tell you that we're pleased with the EAP program. You know that we stopped enrollment of that on the Friday night before the September 22nd CRL because we thought we were getting approved. We continue to the adherency to product in the EAP has been tremendous and gives us great confidence.
As far as building anything into a model, I think they're going to be spread out through the next quarter or two quarters because we will be going through prior auths, appeal processes, peer to peers, so it'll be staggered as when they come onto actual commercial product.
Got it. Thank you.
Mm-hmm. Thanks, Ritu.
Thank you. Our last questioner in the queue coming from the line of Basma Radwan with Leerink Partners. Your line is now open.
Hi, good morning. Congratulations on the approval. Just to follow up on one prior question. Based on your market research, do you expect any difference in the level of adoption between patients who are on Evrysdi versus patients who are on Spinraza, given that there is increased treatment burden with the monthly injections? Also one follow-up question on the dose. Given that the 10 mg per kg dose is the dose that's being recommended, do you think at some point physician may be able to escalate to 20 mg for the CD patients, or that's not the case right now? That's it. Thank you very much.
Yeah. Thanks, Basma. Why don't we take that second part first, Akshay, just on the dose—
Yeah, no, just very quickly on that. The data very clearly show that 10 mg is the optimal, lowest, safest, effective dose, and there'll be no need to go up to 20 mg.
Great. Keith?
And then I think on the first part, you know from where we stand. We really believe as an organization that a patient, their best opportunity and what we will be making a new standard of care is when you're actively treating the motor neuron and actively treating the muscle. From our point of view, we're really agnostic whether on Evrysdi or Spinraza or quite frankly, high-dose Spinraza. If it's good for them, and then we can help by targeting the muscle directly, that's where we would aim to be. Do I think that it expands the potential marketplace? It's quite possible because at the end of the day, these patients have never been able to directly treat muscle.
I do think that whether they're on Evrysdi or whether they're on nusinersen, I just don't think that that will be the key factor into why they decide whether ISEMBYLD is going to be the right choice for them.
Yeah, and I think, Basma, just make a closing remark on the call. I think that over these last 10 years where the SMN-targeted therapies have brought needed innovation to the SMA community, it's with the understanding of how important SMN protein increase is for motor neuron health. And I think now we're ushering in the next phase of innovation, and I think there's a greater appreciation that the body's natural negative regulator for muscle growth is probably not something that is particularly helpful for patients with SMA. And so now we have the first and only muscle-targeted therapy ever approved by the FDA for patients with SMA.
We are excited that patients can now benefit from both increased SMN protein production as well as safe and effective inhibition of myostatin, which as I noted, is the body's natural negative regulator of muscle growth. We are super excited to be ushering in this next phase of innovation and look forward to keeping everybody apprised as our launch progresses. Thank you very much.
Thank you. Ladies and gentlemen, this concludes today's conference call. Thank you for your participation, and you may now disconnect.