You may now begin your call.
Thank you. A press release was issued earlier today with our first quarter 2026 financial results and business update. This can be found on our website, along with the presentation for today's webcast. Before we begin on slide 2, I'd like to remind you that forward-looking statements may be presented during this call. These may include statements about our future expectations, clinical developments, regulatory timelines, the potential success of our product candidates, financial projections, and upcoming milestones. Actual results may differ materially from those indicated by these statements. argenx is not under any obligation to update statements regarding the future or to conform those statements in relation to actual results unless required by law. I'm very excited to be joined on the call today by Karen Massey, our new Chief Executive Officer.
Today is her first official day on the job, marking a very important milestone in the story of argenx. We're also joined by Karl Gubitz, Chief Financial Officer, and Sandrine Piret-Gérard, Chief Commercialization Officer. I will now turn the call over to Karen.
Thanks, Beth. Welcome, everyone. I'll begin on slide 3. I want to start by saying what a privilege it is to step into the CEO role at this point in argenx journey. I joined the company 3 years ago for the culture, the science, and the opportunity to help build a different kind of immunology innovation company alongside an exceptional team, one that scales innovation through collaboration, delivers meaningful impact for patients, and creates lasting value for all stakeholders. I'm excited to carry forward Vision 2030, our roadmap for growth and value creation at a moment when we have so much opportunity across the near, medium, and long term. Near term, we see continued growth with Vyvgart across both MG and CIDP.
While we see the typical effect of seasonality, the underlying demand trends remain very strong and continue to point to a business that is both growing and expanding. I'm particularly encouraged by our new patient demand. Q1 was amongst our highest quarters ever. Our leadership in neuromuscular was on display at AAN last month, where consistently strong efficacy and safety data reinforced why physicians should treat broadly and earlier with VYVGART in both MG and CIDP. Importantly, that growing confidence amongst neurologists positions VYVGART well for the next phase of growth, with potential expansions into seronegative, ocular, and pediatric MG populations based on the strength of ADAPT-SERON, OCULUS, and JUNIOR. When I consider the growth over the medium term, we see strong runway of launches ahead, reflecting the scale of our ambition and the depth of opportunity across our pipeline.
We're advancing into rheumatology with readouts in autoimmune myositis and Sjögren's. We expect the first readout and potential launch of our second medicine, empasiprubart, in MMN. Lastly, we're investing in our future. We're building a pipeline of novel biology relevant in diseases of high unmet need, positioning us to sustain long-term growth and reach thousands more patients. Slide 4. Our strategy is ambitious. It's one we know how to execute. Vision 2030 is built on a proven immunology innovation model that has already delivered a strong foundation. Today, we have five clinical-stage molecules that follow our model, first-in-class against a novel immune target and collectively addressing more than 15 distinct diseases. Empasiprubart is positioned to be the second medicine we bring to patients. Like VYVGART, we built this molecule very intentionally to target C2, leveraging novel biology insights from leading experts in complement biology.
Through empasiprubart's development, we've also unraveled critical insights into MMN biology that position us to fully transform the treatment paradigm. The phase III readout is expected in 4Q, bringing us closer to launching our second medicine. In MMN, we see a familiar opportunity, build and lead the category, much as we did with VYVGART in MG, transforming the entire disease space. In CIDP, we have the same ambition. We continue to grow our market share with VYVGART and are generating extensive real-world insights as patient experience increases. Now, by advancing a second targeted approach with empasiprubart, we will deepen our understanding of the underlying biology, helping us learn which patients benefit most from which treatment and positioning us to secure leadership in CIDP. Slide 5. Across VYVGART and empasiprubart, we're solidifying our leadership in neuromuscular diseases and amongst these physician and patient communities.
One of the most critical therapeutic area expansions for argenx is into rheumatology, and this starts with an important phase III readout of autoimmune myositis in the third quarter. This is a disease with significant unmet need, defined by progressive muscle weakness that makes basic daily activities really challenging, if not impossible. There are no approved treatments in necrotizing myositis and in dermatomyositis, where serious symptoms can emerge in the muscle, in the skin, and in other organ systems. The complexity of the disease means more innovation is needed. VYVGART has the potential to be the first truly targeted therapy in this indication, targeting autoantibodies against proteins that are highly expressed in the muscle.
In the case of positive data, we plan to take an approach similar to what we've done with MG and CIDP because the autoimmune myositis opportunity has similar attributes, overlapping physician community, long-established conventional treatment patterns, and our goal is to transform patient outcomes and become the number 1 prescribed biology. Slide 6. We've significantly broadened the number of clinical candidates across our pipeline in the last 12 months. You can expect to see this cadence continue. adimanebart is in phase III in CMS. ARGX-121 is in phase II development in IgAN with more indications to follow. Our long-term FDRA portfolio is taking shape with ARGX-213 ready for phase III and ARGX-124 to follow. To expand our pipeline at a cadence that will sustain our long-term trajectory, we need to deliberately expand the ecosystem from which we source novel biology.
We'll double down on collaborations and licensing agreements with academic institutions and biopharma companies alongside acquisitions and strategic investments, giving us the flexibility to engage in whatever form accelerates innovation into our pipeline. The establishment of our China entity supports this strategy, building on the clinical and commercial strengths of our partnership with Zai Lab and embedding us into the local ecosystem to effectively access emerging innovation, accelerate evidence generation as part of our pipeline and product strategy, and ultimately expand our impact in this region. As I step into this new role, I'm reminded of our purpose as a company, our patients. When we launched VYVGART 5 years ago, we made a commitment to continue raising the standard of care for people living with myasthenia gravis. Today, with 17 consecutive quarters of growth, we continue to see that commitment translate into real-world impact in MG, in CIDP, and in ITP.
This is what gives me confidence in the opportunity ahead. We're deeply committed to our purpose. We're disciplined in our execution, and we'll be flexible in how we source innovation. With that, I'll turn the call over to Carl to walk through our financial performance and outlook.
Thank you, Karen. Slide 7. Product net sales for the first quarter were $1.3 billion, representing 63% year-over-year growth. By region, we generated $1.1 billion in the U.S., $67 million in Japan, $112 million in the rest of the world, and $12 million in product supply to Zai Lab in China. The 1% quarter-over-quarter growth reflects the impact of Q1 seasonality in the U.S. and is aligned with our expectations. Credit adjustment and net progress consistent per quarter. Next slide, Slide 8. Total expenses this quarter were 9% as decreased 6% compared quarter of last. In development expenses injector in 2027, continued development of efgartigimod across several indications, and advancing our pipeline assets. These strategic investments will deliver long-term growth through innovation in providing transformational outcomes to patients.
SG&A decreased 17% quarter-over-quarter, reflecting higher discretionary expenses in the 4th quarter of last year. We delivered an operating profit of $394 million in the 1st quarter, an operating margin of 30%, representing 183% year-over-year growth. With revenue growth exceeding operating expense growth, we are on a clear path of continued margin expansion, demonstrating the operating leverage we are building as VYVGART scales and we advance our pipeline. Tax for the quarter is in line with expectations at 14% of profit before tax. We ended the quarter with a cash balance of $4.9 billion, including cash equivalents, and current financial assets, an increase of more than $400 million from the beginning of the year. This strong financial position gives us significant flexibility as we deploy capital to fuel long-term growth.
Our capital allocation priorities are clear: maximizing the VYVGART commercial opportunity, advancing our pipeline, strengthening our supply chain, and pursuing business development opportunities to source the novel biology that will fuel our long-term growth. With our profitability profile, we are investing from a position of strength to deliver on Vision 2030. I will now turn the call over to Sandrine, who will provide details on the commercial front.
Thank you, Karl. I'll begin on slide 9. Over the past several months, I have spent a lot of time with our field teams and meeting with physicians and patients. What stood out to me is how argenx translated differentiated science into execution in the market. From securing access to building physician confidence in VYVGART in MG, CIDP, as well as in ITP in Japan, and to delivering wide growth patient support designed to help patients start and stay on therapy. This level of disciplined execution and building trust among our core stakeholders will be critical as we approach several important growth catalysts. Today, I'll focus on what is driving our performance and where we see the most meaningful opportunities to build from here under Vision 2030. Slide 10. We continue to deliver on our long-term growth strategy in 2026 with strong momentum across all indications and all regions.
Our fundamentals are incredibly strong. Now 4 years into MG and 2 years into CIDP launch, we see no signs of demand slowing. In the first quarter, new patient starts were amongst the highest since launch, and we continue to have an expanding prescriber base, reflecting increasing confidence in Vyvgart. We now have over 5,000 neurologists prescribing Vyvgart in the U.S. Since launching in CIDP, we have effectively doubled our prescriber base, and each incremental addition meaningfully expands the numbers of patients we can reach. We are also seeing a change in prescribing behavior. Across both MG and CIDP, we are seeing a clear shift toward earlier use of Vyvgart as physicians gain confidence with what it can offer patients. In the U.S., our market research now shows that 4 out of 5 HCPs prefer to start with Vyvgart as the first targeted biologic in gMG.
New patient demand continues to build across both indications, driving consistent quarter-over-quarter patient growth. The pre-filled syringe has materially changed the demand of VYVGART. By giving patients and physicians more flexibility, it continues to drive earlier adoption across MG and CIDP, with 68% of PFS patients being new to VYVGART since launch. Slide 11. VYVGART is the number-one prescribed biologic in gMG, a market that continues to grow. We still believe the biggest opportunity is ahead of us, particularly given that nearly 80% of MG patients were not yet on a biologic. We know the VYVGART profile is resonating with physicians in this population. More than 70% of patients starting VYVGART today come directly from oral therapies. This continues to be the focus of our strategy to extend our leadership by reaching patients earlier in their treatment journey and expanding our reach to broader MG populations.
The data we presented at AAN served as an important driver of this strategy, and we were excited by the positive response from neurologists. Vyvgart is delivering fast, deep, and sustained efficacy and safety across MG patients. This supports our ambition for Vyvgart to be the targeted treatment of choice, simplifying decision-making for the HCP and underscoring Vyvgart's growth potential. I want to share one patient story that underscores why this matters. Pam first presented with blurred vision and muscle weakness around her eye. Her ocular symptoms were not taken seriously, and she was unable to access appropriate treatment. As her disease progressed, she ultimately generalized, suffered a serious fall, and was hospitalized. When Pam later started Vyvgart, the impact was meaningful, helping her regain both mobility and independence. Her experience is a powerful reminder that ocular MG is not a mild disease.
It can be profoundly debilitating and disrupt independence in ways that are often underestimated. Our positive ocular MG data, which demonstrated consistent improvements in both ptosis and double vision, bring us closer to extending innovation for these patients. We are now three days away from our PDUFA date for seronegative, we are limited in what we can say at this point. A potential approval represents a meaningful opportunity to reach patients without detectable acetylcholine receptor antibodies, up to 11,000 additional patients in the U.S. Many of them have been left out of studies or lacked access to targeted innovation, this commitment is what drives us every day. Slide 12. Turning to CIDP, we continue to see consistently strong patient adds quarter-over-quarter, with nearly 80% of new starts coming from direct switches from IVIG.
As neurologists gain real-world experience and digest emerging data, they are becoming more thoughtful about when to introduce a targeted therapy like VYVGART and are increasingly considering earlier use. Physicians are citing VYVGART's functional outcomes as a key differentiator, particularly our grip strength data. When CIDP patients were followed from ADHERE to the open-label extension, mean grip strength continued to improve with weekly treatment up to 96 weeks. One neurologist shared that it is rare to see patients regain function after deterioration, which makes an observed recovery in grip strength especially compelling. We remain focused on understanding how best to serve the broader CIDP population and how we can shape the market for earlier use of VYVGART. We are steadily expanding within our initial 12,000 patient addressable market and are seeing our strategies work increasingly beyond it.
At AAN, we presented the post-hoc analysis of the ADHERE study showing 87.5% response among treatment-naïve patients, which continues to support this effort. As we look ahead, we're focusing on repeating what has already proven successful. The commercialization playbook we built in MG and CIDP is repeatable, combining a patient-first access strategy, deep prescriber engagement, and disciplined execution. This positions us well as VYVGART expands into new indications and as future medicines, including empasiprubart, move closer to launch. With that, I will now turn the call back over to Karen.
Thank you, Sandrine. Slide 13. Putting patients first is how we define success at argenx. I'm incredibly proud of what this team has accomplished, and I'm energized by what lies ahead. I'm grateful for the trust of our patients, our partners, and our shareholders as we continue this journey together. Thank you. With that, operator, we'll open the call up to questions.
Your first question comes from Anupam Rama from Guggenheim Securities. Your line is open.
Good morning, everyone. Thank you for taking my questions. First, congratulations to Karen on the CFO confirmation. Really, really good. Perhaps 2 questions from me. Would love to hear, Karen, would love to hear your perspective on the outlook of argenx as you see it. Once you are fully settled in the role, do you anticipate or should we think about any sort of changes to the company's strategic direction? That's one. The second one is more around VYVGART. You do have 2 significant label expansion opportunities ahead of you. You probably will have the broadest label for MG across, you know, various subsets. How does this change the growth outlook as we head into second half? How do you expect this differentiation to play out from a competition standpoint? Thank you.
Yeah, thank you for the questions and for the congratulations.
Apologies. We are just having a technical difficulty. We'll be right back with you.
Kevin said no, there's nothing.
We have the speakers back with us now. Apologies for that.
Okay. Thank you very much. Can you hear me now? Okay.
Yes. Great.
I'm gonna do very well. Well, thank you, sorry, we're having some technical issues here. A great first day as CEO. Indeed, I appreciate the congratulations on the new role. I'm really excited to be taking on this role at this time for the company. We're in such a position of strength with a really strong quarter and strong momentum, there's so much opportunity and momentum ahead. In terms of the question around strategic priorities, as I step into the role, my priorities are very clear. I mean, I was very much involved with Vision 2030, there won't be a change in that strategy. For us, Vision 2030 is not just an aspiration, but it's a growth strategy.
When you look at what we've laid out for that strategy, by the end of the decade, we want to have 2.5 times patients on VYVGART. We want to have 3 times more indications approved and 5 molecules in late-stage development. Those 5 molecules in late-stage development really set us up for the next decade of growth. There's no change to the strategy, and I'm incredibly optimistic about our future. In terms of your second question on label expansions, we've laid out a strategy in MG for continued growth by bringing continued innovation to the market. We have our PDUFA date for seronegative in 3 days.
Beyond that, we have ocular MG that we'll be filing quickly, and we're also looking at an expansion into the pediatric population in the future. As you say, with this, we should in MG have the potential to have the broadest label and be able to reach the broadest set of patients. We see this as a huge differentiator in the market. What we're already seeing today is that physicians are choosing VYVGART four out of five times for their early line patients as their first biologic. We see really strong momentum already, and that growth strategy of expanding our label should continue that momentum through this year but also into the future. Thanks for your questions.
Your next question comes line of Tazeen Ahmad from Bank of America. Your line is open.
Okay, great. Good morning. Thanks for taking my question. Karen, there's a big second half of the year upcoming for the company with several data readouts. I did want to focus my question on myositis in particular. Can you clarify your view of the likelihood for success for each of the 3 subtypes that you're studying? You know, in particular, do you feel like any one is more likely to work than the others? I think some people recently have interpreted comments you've made to indicate that you might be less bullish on DM. Thanks.
Thank you so much, Tazeen, and appreciate the pipeline question early on in the earnings call. Yeah, as you said, the second half of the year is exciting. Myositis is our entry into rheumatology. We should remember this is a first-in-class opportunity, this is a wide space opportunity. We have a very thoughtfully designed trial that really lets us explore and understand across 3 different subtypes. Each of those subtypes is grounded in a very strong biology rationale, and you'll recall that we had phase II data in these same 3 subtypes, and we did move forward into phase III. What we see as a win is a positive study, meaning statistical significance on the primary endpoint.
More broadly, I think what's important in myositis is that there's significant unmet need across myositis broadly. We've been talking about IMNM quite a bit recently because we've had some learnings around IMNM. Specifically, as we've been learning about IMNM, leading up to the readout and looking into the data in more detail, what you see is that because IMNM, those patients have no treatments available, it is severely underdiagnosed and undertreated. We see that the TAM opportunity in IMNM is bigger than we previously thought. It's around 20,000 patients. That's more similar in size to a CIDP opportunity and with similar dosing. That's why we've been focused on IMNM. Of course, the other subtypes, for example, DM, also have significant unmet need and with limited treatment options.
IVIG is the only treatment option available there. DM is a little bit more heterogeneous, but we still think that there's plenty of room for multiple mechanisms of action, and we think that Vyvgart has a good value proposition in DM. We're looking forward to the data readout in Q3.
Your next question comes to line of Derek Archila from Wells Fargo. Your line is open.
Hey, good morning, let me add Mike McGrath, Karen, to, you know, stepping into the CEO role. Just two quick questions. First, just on 2Q 2026 VYVGART step-up, like in the last two years, we kinda see that move from 1Q growth to 2Q growth, and we see kind of a nice magnitude of step-up. I guess, can you characterize what we should expect this year? Then just a follow-up to Tazeen's question on myositis. My understanding is that it's not powered for the individual subtypes, but will you give any qualitative information on how the subtypes performed in the phase III? Thanks.
Thanks, Derek. Yeah, let me hand it over first to Karl so that he can give you some comments on the momentum that we have heading into Q2. Then maybe Beth, you can comment on the primary endpoint and communications.
Thank you, Derek. Nice to hear from you. Every quarter has its different dynamics, of course. I think we need to focus on the underlying dynamics, which, as Karen already said, and as we said earlier in the prepared remarks, which are very strong at the moment. Our full-year expectations are unchanged, and you can look at the shape of the curve, which will be consistent with prior years. Thank you for the question, Derek.
Hi, Derek. I'm just on the question about what we're gonna share on the myositis readout. I think at this point, you know the style in which we communicate. Our plan is, of course, to give the outcome of the primary endpoint. The primary endpoint of the study is the mean TIS score, and that is taken at week 52. We also understand the importance of contextualizing that subtype performance. How we do that and what that looks like will still, you know, still to be seen. I think it's important to remember that because this is a new therapeutic space that we're entering, we will need to preserve some of that data for an upcoming medical meeting so that we can inform and generate enthusiasm among the rheumatology community.
Very helpful. Thank you.
Your next question comes to the line of James Gordon of Barclays. Your line is open.
Hello. James Gordon from Barclays. Thanks for taking the questions. Had a question on competition in MG. I've had some questions from investors about competitors in the U.S., such as Amgen, who've been talking about UPLIZNA, CD19. They're talking about strong uptake in both bio naive and switch patients, even without step-throughs. Are you seeing UPLIZNA being used much in MG, and is it displacing or in any patients that could use VYVGART? I think that's the Amgen has said they're taking it into a CIDP trial. Could that be a threat in addition to potentially C1s coming along? From the competitive point of view with Regeneron, they've got cemdisiran, also hitting C5, also as a potential MG approval later this year in Q4.
Do you think that could impact, VYVGART at all in MG?
Thanks for the question, James. There's a lot in there. I'm actually gonna hand it over to Sandrine. She's been spending a lot of time out in the field with customers and at AAN, and I think has probably recent experience to talk from.
Thank you. Thank you, Karen. Thank you, James. Indeed, competition has come. We have put MG on the map, there are more and more players in there, and we see that as a good sign. It means there is a lot of potential in that market, but also more option and innovation for patients, which drives the size of the biologic market, which benefit all of us, and especially Vyvgart as four other fine providers really prefer Vyvgart as the first biologic. Now going to your question specifically on some more recent entrants. What is interesting to see is that most of the recent launches are really positioned towards the later lines, more for refractory patients and after Vyvgart.
We see some use. Not really directly competing with us because what we are trying to do is to go in earlier lines because we know that 80% of the MG market is still not in the hands of biologics, and this is where we see a really big opportunity, and that's our strategy. Some use indeed, but more in later lines and refractory. You also mentioned a recent competitor in CIDP. I mean, CIDP, as you know, we have been in the field for now two years. We have another product in development, empasiprubart, in development. What we believe that CIDP is a progressive disease, but very heterogeneous, and there is space for multiple mechanisms of action.
With the current profile of VYVGART, we believe we have a very strong value proposition between the PFS, the efficacy, the safety, recent group strong data where we showed sustained efficacy up to 96 weeks. Then we just presented the data at AAN on earlier use where we do the post-hoc analysis. I don't know if you saw that one, where we showed that naive patients had a 87.5% clinical efficacy. We are really trying to extend here the overall market for VYVGART, and this is very great for CIDP patients. Now for the C5 question, I think Karen wanted to say something, so I'll hand it over back to Karen.
Oh, thank you, Sandrine. I think that's great, and I think you're exactly on point. As we see new competitors coming into the market, C5s and others, they're mostly being used in the refractory space. Thanks for the question.
Your next question comes from line of Alex Thompson from Stifel. Your line is open.
Hey, great. Thanks for taking our questions, and again, congrats to Karen here. I was wondering sort of to talk at a high level about your appetite for later stage, you know, business development than what you've done historically and maybe in the context of that, you know, how you're thinking about your Fortay equity investment. Thank you.
Thanks for the question. Maybe to take a step back, we talked about our ambition earlier with Vision 2030, over the long term, we wanna become a leader in immunology. What that means is that we're focused very much on building our pipeline. In the past, we've been focused on building our pipeline through partnerships with academic institutions. You all know our Immunology Innovation Program, where we've sourced novel biology that can provide transformative outcomes for patients through those partnerships with academic institutions. As we've been developing a stronger cash balance and financial strength, what that allows us to do is broaden our lens a little bit and also look for other opportunities to source novel biology, that where we can provide transformative outcomes.
Your example, that you're calling out of Fortay is one example of that, where we made a strategic investment, in something that we see as novel biology and, similar to, what you also saw with Tensegrity earlier this year, where we're investing in options, in novel biology. You can expect to see more of this from us as we continue to build our pipeline and continue to leverage our balance sheet. We wanna invest in our internal innovation pipeline, and source novel biology from wherever we can find it. Thanks for the question.
Your next question comes the line of Rajan Sharma from Goldman Sachs. Your line is open.
Hi. Thanks for taking my question. Maybe just on the topic of competition, we saw that J&J are running a head-to-head trial of Imaavy versus VYVGART in myasthenia gravis, which could read out next year. I was just wondering if you could provide your perspectives on the trial design and expectations here. To what extent is that a risk to VYVGART or not conscious of the different formulation? Then a very quick follow-up for Karl. Heard your comments on operating leverage. Should we expect to see this incrementally quarter on quarter as well as on an annual basis? Thank you.
Thank you. I'll take your question on competition, and then I'll hand over to Karl for the question on operating leverage. I think Sandrine said it best. We put MG on the map and many competitors are following us, especially as the first in class FcRn. I think what you see is that we set the standard for efficacy in terms of MSC in MG and have the strongest safety profile, and we have all of these innovations. We started with IV, we launched subcutaneous, and then we most recently brought PFS to market. In fact, PFS is driving the majority of our growth at the moment.
When you think about that, I think the question to ask about some of these studies and these other competitors is what problem are they trying to solve? I think what we're really focused on is how do we bring more value to more patients where there is unmet need. For us, that's focusing on PFS, which is unmatched, as well as focusing on that strategy we were talking about earlier, which is broadening the population through seronegative, through ocular, and in the future through pediatrics. With that being said on competition, maybe, Karl, you can talk about our operating margin.
Thank you. Thank you, Rajan, for the question. I wanna start off by reminding, we are on an innovation mission. The patient is your North Star. We have a unique opportunity now to invest in innovation and set the company up for the long run, to build a long-term sustainable company. That is the capital allocation priorities of the company. That said, yes, you are right. The very successful launch allows us to build a P&L where we already have a very good margin structure. Our gross margin is around 90%. Our operating margin is around 30%. We added $400 million of cash this quarter, getting us to $4.9 billion.
Yeah, you can expect going forward to see margin expansion, every quarter, year-over-year, and we're gonna continue to build on that. That, of course, is not the objective at the moment, but I think we can do both. Thank you for the question.
Your next question comes from Allison Bratzel from Piper Sandler. Your line is open.
Good morning. This is Ashley on for Allison Bratzel. Congrats on the quarter and all the progress. Just for us, just curious to learn more about the go and no-go decision on the phase II VARVARA trial in delayed graft function, which is expected mid-year. What specific clinical or biomarker signals are you looking to see to justify advancing clinical development? Just more broadly speaking, how are you viewing the commercial opportunity in delayed graft function? Thank you.
Hi. Thanks for the question on DGF. As I said earlier, it's great to hear these questions on our pipeline. DGF is an important indication for us for our second molecule, empasiprubart, and we're able to pursue DGF as an indication because of empasiprubart being a C2, so involved in both the classic and the lectin pathways in complement. That's a differentiator for us. In terms of the study, it is a phase II study, so think about it as an exploratory study. What we wanted to do was see the readout of the data for longer term.
We're following the data out to 52 weeks because in this patient population and what we hear from both patients as well as healthcare systems and providers is what they care about is the long-term outcomes. As soon as we have that data, we'll be able to analyze it, and we'll have a go/no-go decision for phase III. Thanks for the question.
Your next question comes from the line of Danielle Brill from Truist Securities. Your line is open.
Hey, guys. This is Alex on for Daniel. Thanks for taking our question, and congrats on the quarter. Another question on myositis. On the placebo response, just curious if you could talk a little bit about what factors are known to drive the placebo response, and do you expect any difference in the three subgroups? Then alternatively, on the steroid taper, just curious what effects of the steroid tapering you're anticipating in the placebo response. Also, do you have any thoughts on why Roivant steroid tapering did not yield any decrease in the overall TIS endpoint in its placebo arm in its DM trial? Thanks so much.
Yeah. Thanks for the question. Let me take them one by one. First, when you think about placebo response, across immunology, you see this pretty consistently. You know, we've seen it in MG, in CIDP, you see it in Sjögren's studies, and similar in myositis. I think this is a pretty common phenomenon. When you're developing in immunology, like we are, you start to get sort of good learnings around how to make sure you're minimizing that placebo response in the trial. That can include things like training the sites to make sure that they understand how best to use the tools and the measures for the primary endpoint, and that type of thing. In this case, as you said, it's TIS.
I don't think there's anything special across the different subtypes or in myositis there. In terms of the steroid taper, we think this is actually a benefit of the design of our study, because what we've been able to do is build it in late enough in the trial, so that you have a systemic steroid tapering, which should actually unmask any placebo response and help us to show a clear benefit on active disease. We see that the way that we've designed it is very elegant, and it should actually help us to uncover the benefit of VYVGART. In terms of Roivant, I would encourage you to ask them. I'm not sure about the details on their steroid taper. Thanks for the question.
Your next question comes to the line of Yaron Werber from TD Cowen. Your line is open.
Great. Thanks so much, and congrats, Karen, again. A couple of sort of interrelated questions. One, can you just give us a little bit of a sense? We're kind of thinking that CIDP is around 40% of sales right now, maybe kind of 37%. I don't know if we're in the right ballpark. Secondly, for the seronegative study, it was a very wide study with a P value of 0.1 across all patients, which you hit successfully. It looks like it was driven by the MuSK and LRP4 positive patients. In the seronegatives, technically the endpoint wasn't met, but because it came together literally at the end, there was a benefit throughout the period.
Just trying to get your conviction that you can get a broad approval and not just in the autoantibody positive. Thank you.
Yeah. Thanks for the questions. I'm gonna hand it over to Karl Gubitz to talk about CIDP and how the mix of business is evolving. I'll turn over to Sandrine Piret-Gérard to talk about seronegative. I wanna just make a point that's really important though, related to the specific question you asked. We're 3 days from our PDUFA date, we have to be very careful in how we talk about this. We're gonna keep the discussion very general. What I want Sandrine Piret-Gérard to talk about is, in general, how you see the seronegative opportunity in the case of approval with, so that we don't go into those details. Maybe we can talk about CIDP first.
Yaron, thank you for the question. Both CIDP and MG are continued to be growth drivers for us. Of course, CIDP is mainly in the U.S. now, but also in Japan and Germany. Other markets we still have to launch. In terms of a percentage breakdown, I don't wanna get into that, but I will say that MG is still the majority of our revenues and of course the majority of our patients, but both still have a lot of growth in them. Thank you for the question. I'm handing over to Sandrine.
Thank you for the question on seronegative. Like Karen said, I will stay very general because we are only three days away from the PDUFA date. If approved in seronegative, as you mentioned, there is a pool of patients which we assess at 11,000 patients that would cover potentially these three subtypes. As we are only three days away from PDUFA date, we are obviously ready to launch. The good news is that we already embedded into MG. There is a big overlap of the prescriber base with more than 80% of the target we already visited that are actually that we cover seronegative patients. We don't need to add any field force.
The prescribers know extremely well, VYVGART, and they trusted their experience of VYVGART and its efficacy that is deemed fast and sustained. We had a good presentation at AAN with lots of questions, so it shows that there is an interest really, and that physicians and providers are really waiting for that. I won't be able to go more into the details, but we should hear in the next few days.
Thank you.
Your next question comes from the line of Thomas Smith of Leerink Partners. Your line is open.
Hey, guys. Good morning. Thanks for taking our questions. Let me add my congrats to Karen on stepping into the CEO role here. It sounds like the VYVGART auto-injector continues to advance, and you're guiding the launch in 2027. Can you just provide an update on where you are with this formulation? What are the outstanding gating factors for bringing this to market, and how are you thinking about potential uptake in this form versus the prefilled syringe? Then if I could, just a clinical follow-up on efgartigimod in Graves' disease. We saw the phase III design that you recently posted on ClinicalTrials.gov. I was wondering if you could comment on some of the design considerations for this multi-part study.
How are the patients being handled between part A and part B, and how are the background ATDs being managed? Maybe just higher level, like what are your expectations with respect to the primary endpoint registrational path? Thank you so much.
Hi. Let me start with the auto-injector question. We're moving into manufacturing stage at the moment, as you say, to get ready for auto-injector launch in 2027. The key on gating factors are really just moving through those different gates of making sure that we're ready for production and approval. In terms of the opportunity that we see with auto-injector, what we saw with prefilled syringe is that it opened up a significantly larger patient population. Actually, we said earlier, prefilled syringe is driving the majority of the growth for us today. With auto-injector, I don't think it'll be as much of a step forward as prefilled syringe. You'll recall that in the U.S., prefilled syringe moved us out of healthcare administration into at-home administration.
The auto-injector will be a step forward in terms of patient convenience and ease. I think that's an important consideration for how we compete in MG. In terms of Graves' disease, ClinicalTrials.gov covers all of the details that we want to disclose publicly. I'm gonna hand over to Beth to talk about some of the additional details.
Yeah. We designed the Graves' study taking into account, of course, precedent studies, and that was aligned with, you know, what the regulators wanted. It's actually going to be 2 studies. You're gonna see some kind of similar attributes of this study, where we're actually dosing on top of antithyroid drugs. We're looking at patients at the end of the study who are euthyroid off antithyroids. You're going to see kind of a tapering off that. You know, I think beyond that, we'll get into more details at a later date. You know, we're really excited about kicking this off. We're focused on, you know, moving enrollment along as quickly as possible. Yeah, more to come at a later date.
Your next question comes to the line of Akash Tewari from Jefferies. Your line is open.
Hey. Thanks so much for the questions. Karen, congrats on the new role. Very well deserved. Just on your phase III myositis trial design, will the FDA allow you to file on pool data, or does each subset need to be statistically significant for broad approval? Additionally, can you go over the rationale of your ADAPT Forward trials that look at VYVGART and EMPA in combination in gMG? What type of signal would you want to see to move that forward in larger studies? Thank you.
Thanks for the question. In terms of myositis, the label that we get, that will be a review decision, and we'll have to see how the data unfolds and let the data speak in each of the subtypes. We look forward to that data in Q3. I'm glad you asked about ADAPT Forward because it's a key part of our combination strategy that I think we're uniquely positioned as argenx to pursue in MG and also in some other of our indications like CIDP. ADAPT Forward is a platform study, and what we're looking at is can we dramatically increase the efficacy and outcomes for patients in MG.
What we're looking at is VYVGART as the backbone of therapy and then looking at different combinations, for example, empasiprubart on top of VYVGART, and can we increase the number of patients reaching MG-ADL? Over time, It's a platform trial, so we will be adding different arms to the trial to explore different combinations of that we have in our pipeline, so that we can explore which we would want to move forward in phase III. Thanks for the question.
Your next question comes to the line of Shawn Lyman from Morgan Stanley. Your line is open
Good morning, Karen and Karl and team. Hope everyone's well. Two questions. The first one is your recent data presented at AAN for VYVGART and treatment in CIDP patients. How do you see that evolving? You know, do you see, you know, VYVGART potentially moving up into the front line? You know, I think there's a lot of focus on just the cost of drug, but, you know, considering you've got just a short injection with VYVGART versus all the palaver that goes on with IG administration, just to give your view there. Second question is just on the IMNM opportunity, and I think, Karen, you mentioned a CIDP-like opportunity. Just, you know, give us a bit more color on the accessibility of that patient base.
You know, are they readily diagnosed? You know, what do you have to do there to get into that market? Thank you.
Yeah, thanks for the question. I'm gonna hand over to Sandrine to talk about the CIDP data. She was at AAN, and then I'll come back to the question on IMNM.
Great question, indeed in my preparatory remark I mentioned that post hoc analysis because I think it's data that we have never presented before, showing that VYVGART can indeed have an impact, a sustainable impact and fast impact and efficacy on naive patients, truly naive patients. A few analysts picked that up, I think this is going to expand the possibilities for VYVGART. If you look at our label, in the U.S. we actually could be used first line, there is actually theoretically no barriers to using. In, in practice, we see two barriers for broader usage in first line. The first one is indeed getting physician comfortable using it, when patients are doing okay.
That is very important to come with convincing data like the one in the post hoc analysis, but also data like we are showing with the grip strength, where we show really very good efficacy on a sustained basis at 96 weeks. The second barrier we are seeing is indeed payers, and you mentioned that in your question. Having data like the one we had in the post hoc analysis allows us to go back to payers and have a discussion because ultimately this is better for patients. We believe this kind of data will help us move the needle step by step into broadening the market in first line for Vyvgart. I'll hand it back to Karen for your other question.
Thank you, Sandrine. In relation to your question on IMNM being a CIDP-like opportunity, the way that we see it is we size the addressable market as around 20,000 patients, but when you first look at the treated population of IMNM in claims data, it looks more like it's around 6,000-7,000 patients. We think that those are quite easily accessible because there is no treatment options available at the moment. Beyond that, what we will need to invest in in the case of positive data is really disease state education to increase awareness and increase diagnosis of this patient population.
What the opportunity that we have is that IMNM is frequently treated by neurologists, and there's quite a lot of overlap with those neurologists with our MG and our CIDP prescribers. We see the opportunity to build this market in the same way that we've built the CIDP market, we've built the MG market, and I think we'll see, assuming positive data, the same outcome in IMNM. Thanks for your question.
Before we go to the next question, I would just like to ask participants if they could please stick to one question per person so we can take as many questions as time permits. Thank you. Your next question, it comes from the line of Gavin Clark-Gartner of Evercore. Your line is open.
Hi, this is Yixion for Gavin. Thanks for taking our question, congrats on the strong quarter. Question about the next generation ARGX-213, we saw it's become phase I ready. Wondering, can you share more details on the timeline and how you are thinking about indication selection? Also for the phase III, will it be a non-inferiority study head-to-head against VYVGART, or it's gonna be a standalone placebo-controlled study? Thank you.
Yeah. Thanks for the question. The strategy that we're laying out for FcRn is to continue our leadership for decades to come. As you mentioned, we have ARGX-213, which moves dosing to every four weeks, and we also have ARGX-124, another next generation asset in the FcRn space, as well as our program focused on developing an oral FcRn. We have a portfolio of options here for how we'll continue to build the FcRn space, explore the FcRn biology, and deliver value to patients. We aren't public on our clinical development plan for ARGX-213 yet, but it is phase III-ready, and we'll be moving quickly. We see a few different opportunities.
One is to advance patient outcomes in the indications we already have approval for with a more convenient ARGX-213 being a more convenient option. We have the opportunity to expand the indications that we have FcRn approval in. Continuing to expand the boundaries, if you will, of FcRn biology. We're really excited about our full FcRn portfolio, and we think that it'll be able to deliver growth for many years to come. Thanks for the question.
Your next question comes from line of Samantha Semenkow from Citi. Your line is open. Samantha, your line is open. Your next question comes to line of Jakoeb Michiels from KBC Securities. Your line is open.
Hi there, thanks for taking my question. I have one maybe further down the line on the oral FcRn and your collaboration with UNP. Maybe if you can share a bit more on how that's evolving. A follow-up on that, you know, we see other disease areas.
That if you introduce an oral, that could expand the market. I'm keen to hear your view on the potential impact of an oral FcRn on the overall biologics market in MG and CIDP. Could this lead to further market expansion, or do you see it more as a tool to prevent the competition from taking existing share?
Yeah, thanks for the question on the oral. Our partnership with UNP is progressing incredibly well. They're great partners. We're partnering with them on a number of targets and FcRn being the first one. Exactly as you said, our strategy here is that we believe an oral FcRn can expand the market. You can imagine there are patients earlier in disease that would prefer to have an oral option rather than an injectable, even if it is a PFS that we have with Vyvgart.
The strategy here, across all of our indications, and as I mentioned on the prior question, even potentially in new indications, is that we'll be able to bring more convenient options to patients that continue to deliver the same efficacy and safety standard that we've seen with VYVGART. Thanks for the question.
Your next question comes from the line of Victor Floc’h from BNP Paribas. Your line is open.
Hi, thanks very much for taking my question. Maybe just a quick follow-up on ARGX-213, and I mean, I was looking at the initiation of the Graves' disease phase III. I was just wondering, how should we think in terms of additional VYVGART phase III studies in new indication moving forward? Basically, should we assume that the Graves' disease program will be VYVGART's final phase III for new indication, and that any promising signal from the ongoing proof of concept studies will instead be pursued with the ARGX-213 due to IP consideration? Any comment on the lifecycle management there would be helpful. Maybe if I can just squeeze 1 on the CIDP. You've mentioned that the penetration of the biologics in the MG was around 20%.
Can you share the same metrics for CIDP, and can you discuss like the drivers that you have to further like penetrate the market there? Thanks so much.
Yeah, let me take the first question, and I'll hand over the question on CIDP to Sandrine. For Graves' disease, it's, we're pursuing Graves' as an indication for VYVGART. I wouldn't assume that future indications that we name are all going to two, one, three or one, two, four or any of our future pipeline. We still see that we have a lot of runway with VYVGART and a strong development program with VYVGART. We continue to invest, and we'll continue to grow VYVGART. In parallel, we'll be developing two, one, three, one, two, four, and the oral as well. As I mentioned earlier, we see those molecules as a real expansion opportunity for FcRn.
Let me hand it over to Sandrine to talk about the CIDP opportunity and market growth opportunity.
Yes, I like that you picked that up on the 80% in MG, you know, being still among orals, where there is a huge market opportunity. We see something similar with CIDP. The total number of diagnosed patients for CIDP in the U.S. is 42,000 patients, and 24,000 of these patients are treated. That means the remaining are not right now. They have been diagnosed, but they're not treated. Out of the 24,000 patients, 12,000 of them are on IVIG but are not optimally treated, and these are the ones we have been focusing on when we started launching, because these are the ones that have a reason to switch to something better, and that's why we feel that Vyvgart is the answer.
The other 12,000 that are treated and feel optimally treated with IVIG could also potentially switch to VYVGART because could benefit from efficacy like the Greek string data where we showed strong efficacy. If you have to compare the 80-20 split of MG with what we see here in CIDP, I would say out of the 42,000, only 24,000 are treated. The others are not. There is room there. 12,000 feel optimally treated, but there is an opportunity for us to expand the market beyond what we already see today. Still a big potential beyond what we have focused on until now.
Great. Thank you, Sandrine.
Your next question comes from the line of Myles Minter from William Blair. Your line is open.
Hi, team. This is John on for Miles. Thanks so much for squeezing us in here. Wondering if you could talk a little about how you're viewing the evolving CIDP complement development landscape, especially as some of the early C1s inhibitor data has been suggestive of potentially best-in-class profile there. As a follow-up, maybe if you could just talk a little bit about your views on knocking down both the lectin and classical pathway with C2 versus just knocking down the classical pathway.
Yeah, thanks for the question on empasiprubart. It's, it's exciting to be bringing our second medicine, potentially to market, with our readout, our first phase III readout at the end of this year. Certainly from my perspective, on the competitive data, I see this as a real confidence booster for why we're pursuing empasiprubart in CIDP. It demonstrates that there in CIDP, IgM is part of the driver of the disease and complement is at play. That reinforces why we think empasiprubart could have best-in-class potential in CIDP. I think from a company perspective, argenx is very well-positioned in CIDP. You know, there hasn't been innovation in CIDP in 30 years. The first innovation was VYVGART, and now, as we develop that market, we also in parallel are developing empasiprubart.
I think what you'll see is that we have the opportunity between VYVGART and empasiprubart to really shape that market and transform the market, and I think it'll look very different in the future from where it looks today, as we really raise expectations of patients of what they can get from their medicine. We're excited for that. In terms of the classic and the lectin pathway, the reason we chose C2 was very specific, and one of the reasons for that is because there are indications where the lectin pathway plays an important role. I was talking about DGF earlier.
We think that it gives us better pipeline in a product opportunity by targeting C2 to be able to get that, the efficacy benefit there, but also the safety benefit of leaving the alternate pathway intact. Thanks for the question.
Your next question comes from Samantha Semenkow from Citi. Your line is open.
Hey, good morning. Thanks for taking the question. Apologies for the technical difficulties. Just wanted to follow up on a couple of the previous questions on combination strategy for both CIDP and MG. You know, how do you think about the market involving? It seems combo therapies is growing theme within I&I. As you start to see some of that data in the platform trials that you talked about, Karen, how do you see the market evolving there and your opportunity to continue being a leader in both indications? Thanks very much.
Yeah, thanks for the question. We had some technical difficulties earlier today as well, no problem. In terms of our combination strategy, as you see, as you said, you can see that this is emerging in I&I in a way that it's similar to how it did in oncology as well. We're at the forefront of that and we're driving innovation, and I think we're very clear on what we want to achieve. You know, the value proposition for combination therapy has to be that it substantially raises efficacy outcomes for patients. I think that's the bar that we need to see in combination therapy, and you have to be able to deliver that efficacy benefit without a safety trade-off.
That's what we'll be looking for in the platform studies with the different approaches, the different combinations that we'll be testing. As I said earlier, the reason we did a combo platform study is that that will allow us to test these quite quickly. When we see a signal, we'll be able to move quickly into phase III with the goal that we always have as a company of elevating outcomes for patients. Thanks for the question.
That's all the time we have all the questions we have time for. I'd like to hand the call back over to Karen Massey for closing remarks.
Thank you, everyone, for the questions and the great discussion. We'll see you next quarter.
That does conclude our conference for today. Thank you for participating. You may now all disconnect.