Good morning. My name is Rob, and I will be your conference operator today. I would like to welcome everyone to the call. At this time, all lines have been placed on mute to prevent any background noise. After the speaker’s remarks, there will be a question-and-answer session. Thank you, I'd now like to introduce; Beth DelGiacco, Vice President, Corporate Communications and Investor Relations. You may now begin your conference.

Thank you. A press release was issued earlier today with our First Quarter 2025 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 development, regulatory time lines, 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 these statements in relation to actual results unless required by law. I'm joined on the call today by Tim Van Hauwermeiren, Chief Executive Officer; Karl Gubitz, Chief Financial Officer; and Karen Massey, Chief Operating Officer. I'll now turn the call over to Tim.

Thank you, Beth, and welcome everyone. I'll begin on slide number three. At argenx, we are building our company for the long run. Our strategic decision-making paired with an agile approach, has positioned us to deliver sustained growth in a dynamic and evolving market landscape. It's with this same long-term focus that we introduced an ambitious Vision 2030 to reach 50,000 patients across 10 labeled indications and advance five Phase III assets. This quarter, we continue to execute against a bold innovation agenda, keeping us firmly on track to realize this vision. . We successfully launched the pre-filled syringe in the U.S. and Germany to reach more patients with VYVGART. We are advancing 10 registrational and 10 proof-of-concept studies across our pipeline, and we remain on track to progress 4 INDs in the clinic this year with ARGX-109 and ARGX-213, now in Phase I studies. Slide 4. Our focus on execution continues to yield results. Let's begin with our commercial business, where underlying growth is exactly where we expected to be. Consistent with last year, first quarter results reflected typical seasonality following an exceptional fourth quarter. Karen will share more details on launch dynamics later in the call with big picture, key physician and patient metrics across both gMG and CIDP continue to be strong. Looking at the full year ahead, we remain confident in our ability to drive consistent growth. First, we were thrilled to receive an optimal label in the United States with the recent FDA approval of VYVGART Hytrulo pre-filled syringe for self-injection. This comes at the perfect time to maintain our growth momentum and broaden our patient reach in gMG and CIDP. We are excited with the opportunity ahead for CIDP and have just launched our patient activation campaign. This will be critical to empower CIDP…

Thank you, Tim. The first quarter 2025 financial results are detailed in this morning's press release. Total operating income in the first quarter totaled $807 million. This reflects $790 million in product net sales and $17 million in our operating income. The product net sales of $790 million represents 99% growth compared to a corresponding prior year quarter. The product net sales breakdown by region to $681 million in the U.S., $32 million in Japan, $57 million in the rest of the world and $20 million of product supply to Zai Lab in China. On a quarter-over-quarter basis comparing Q1 2025 with Q4 2024, the growth is 7%, with the U.S. growing at 5%. We saw strong underlying demand in both gMG and CIDP with growth in net sales impacted by two factors. First, typical Q1 seasonality with reverification of benefits for patients and second Medicare redesign took effect on January 1 which accelerated the evolution of our channel mix to Part D. This had an impact on gross to net for the quarter. We expect PFS self-injection to further drive a shift to Part D, though, over time, the impact on revenues from increased gross to net will be offset by patient volume growth. Specifically our ability to reach new patient populations with PFS for self-injection. In Japan and the rest of the world, the quarter-over-quarter growth continues to be in the high teens. Next slide. Cost of sales is $81 million in Q1. This reflects a gross margin of 90%, which is in line with previous quarters. Total operating expenses in Q1 2025, $668 million, a quarter-over-quarter growth of 2%. The increase is explained by a $12 million increase in R&D, offset by a decrease of $10 million in SG&A. This results in operating profit for Q1 of $139 million. The quarterly net financial income is $36 million. We benefit in the quarter from unrealized exchange gains of $27 million on our non-U.S. denominated cash balances. The effective tax rate for Q1 2025 is 16%. After tax, the profit for the quarter is $169 million. Our cash balance represented by cash, cash equivalents and current financial assets is $3.6 billion at quarter end, an increase of $238 million from Q4 2024, driven primarily by cash flow from operations. Our previously issued guidance on total R&D and SG&A for the year remains unchanged. I will now hand it over to Karen.

Thank you, Karl. Slide 9. Our patient-centric approach to innovation continues to deliver real-world results as we have now successfully brought a first-in-class medicine to patients across multiple markets executing launches across 3 indications, 3 product presentations in over 30 countries in less than 4 years. With this launch cadence, we have maintained steady momentum and delivered 13 quarters of growth. This is a remarkable achievement, and I'm incredibly proud of the entire argenx team for the focus, dedication and the collaboration that has made it possible. We continue to drive meaningful impact with VYVGART, expanding our reach to new patients and prescribers in both CIDP and gMG as well as ITP in Japan. With the recent approval of our pre-filled syringe which further enhances patient access and convenience, we expect that momentum to continue. Today, I'll walk you through the dynamics behind our performance this quarter and how we're positioned to continue to drive sustained long-term growth and delivering lasting outcomes for patients. Slide 10. We're continuing to deliver on our long-term growth strategy with 99% year-over-year revenue growth for the quarter and steady growth delivered across every region and indication. After an incredibly strong fourth quarter, we faced typical first quarter seasonality in the U.S., which similar to last year, is primarily due to benefit reverification. This quarter also marked the first industry-wide impact of Medicare Part D reform, which is accelerating the evolution of our channel mix towards Part D. As Karl outlined, due to this dynamic, we saw an impact on our gross to net over the quarter. Looking beyond these technical impacts in the U.S., we saw a strong quarter, and we continue to deliver consistent growth. I am very pleased with our performance in new patient starts, in new prescribers and in high patient…

Thank you, Karen. We have an incredibly strong foundation to deliver significant growth this year and beyond, which puts us perfectly on track to achieve our Vision 2030. We have the benefit of a strong financial position to continue investing in our commercial business and early innovation. With multiple expansion opportunities ahead, we plan to sustain our growth trajectory in MG and CIDP. Additionally, we have a steady cadence of several milestones across the robust pipeline, which will further contribute to patient growth and support our leadership in autoimmunity. Execution has always been a key strength of our company, and therefore, we entered the remainder of the year confident in our ability to deliver value to our patients and shareholders whose long-term support has been critical to our success. We will now open the call for questions.

[Operator Instructions] Your first question comes from the line of Tazeen Ahmad from Bank of America.

I wanted to ask a more broad one on the profile of the gMG patients at this stage of the launch that are starting with VYVGART therapy. So can you just tell me what portion of the curve you're on in terms of onboarding the patients that are there -- that are not currently receiving therapy? And then also, are you noticing any changes in discontinuation rates and any impact from competing products so far?

Thanks for the question, Tazeen. Appreciate it. And as you say, I mean, where I come from with 13 quarters into the launch for MG, and I'm really proud of the fact that we've continued to deliver growth quarter-over-quarter despite of a very high last -- in Q4. And I think what that indicates is that we're still early in the launch curve for MG. What we see in terms of the patient profile to your specific question, we still see about 60% of patients coming to VYVGART from orals. So it shows that we're still moving into earlier lines of treatment, which is exactly the strategy that we're pursuing as we expand the market. And what we're seeing is the market for biologics is growing and VYVGART is leading that growth. We maintain the #1 market share amongst biologics in MG. So we're expanding our leadership and pre-filled syringe and the launch of pre-filled syringe is only going to accelerate this as we continue in the launch. So I would say we're at the early phase or early stages of the launch curve at this point. Thanks for the question.

Your next question comes from the line of James Gordon from JPMorgan.

Hello. James Gordon, JPMorgan. Hello, can you hear me? This is James. Can you hear me?

Yes, we can hear you James.

Hello, you can hear me, okay?

Yes, James, we can hear you.

We're experiencing some technical difficulties with that line. We're going to move on to the next question from Alex from -- sorry, Alex Thompson from Stifel.

Congrats on the quarter. I guess as we think about the PFS launch now with 3 VYVGART forms in the market, can you talk about how we should think about net price over time?

Yes. Thanks. Happy to talk about the PFS launch. Maybe I'll just start by saying that we're really pleased with the label that we received as part of the approval and I want to share a huge congratulations to the team. We did get the optimal label. And what we're seeing already is positive feedback from the PFS launch from both prescribers and from patients saying that it's a game changer. So we think that this will be an expansion opportunity and that it will drive growth -- continued growth for VYVGART through the year. So maybe, Karl, you want to comment on the gross to net.

Yes. Thank you, Alex. PFS will, of course, be pharmacy benefit and the gross to net will have a different dynamic in the pharmacy benefit versus the medical benefit due to the 20% manufacturers have to pay for patients in the catastrophic phase. Therefore, the net price per patient for PFS, patients will be lower than for patients in the medical benefit, which will largely be IV and VYVGART Hytrulo. At the moment, we will maintain the 225,000 for an MG patients and the 450,000 for CIDP patients, but over time, that will evolve, and we're going to give you updates later on.

Do you want to also just answer discontinuation question from the last.

Yes, Tazeen, sorry. I think you asked about discontinuation as well. And so just to come back to that, we're not seeing any shift in discontinuation. In fact, we see the consistent discontinuation rates, and I would say given that it's a maintenance therapy and chronic treatment, it's quite strong, and you can see that the patients are definitely appreciating staying in MSE and the adverse event profile. So no shift in discontinuation rates for MG.

Your next question comes from the line of Vikram Purohit from Morgan Stanley.

Ours is on CIDP. If you could just help us understand in a bit more detail. The cadence of new patient starts, where you ended 1Q with in terms of patients on therapy and how you might expect that to trend throughout the course of the year?

Yes. Thanks for the question on the CIDP launch. So we're really excited about where we are with the CIDP launch. What we've seen is continued momentum since the beginning of launch and through Q1, the execution continues to be strong. When you look at the underlying fundamentals, to your question, what we see is continued new patient adds quarter-over-quarter. We also continue to see new prescriber growth quarter-over-quarter, which is a really important measure to demonstrate that we're reaching more prescribers and therefore, reaching more patients. . And the other really important feedback that we have from this quarter is the consistent patient story that we're hearing about the transformational impact that VYVGART is having on their CIDP. So I mean, patients are at the center of our launch and are the key to the CIDP launch. We launched our DTC campaign in Q2 and what we're seeing is that more and more patients are initiating the request to switch with their prescribers and in the majority of cases, their neurologists are granting that switch request. And what that shows us is that neurologists believe in the profile of VYVGART for CIDP. So all of the underlying launch metrics for CIDP continue to be very strong.

Your next question comes from the line of Rajan Sharma from Goldman Sachs.

Just to -- just follow up on the Q1 effects. You mentioned that there were 3 factors that you kind of talked to as being headwinds to revenue growth for the quarter. So that was a reverification and then the Medicare redesign impact. Could I just push a little bit on relative magnitude of each of those and which was the larger impact in Q1?

So Rajan, thank you for question. Let me talk about the gross-to-net impact. In prior quarters, we've seen a gradual increase quarter-over-quarter of Part D. At the close of Q4 2024, it was a minority, a small portion of patients. At the last earnings call, we discussed that in 2025, we have a launch of PFS self-injections, patients under the pharmacy benefit, which is Medicare Part D, will grow. And as that mix evolves between medical and pharmacy, the gross-to-net will increase. What we've seen now in Q1 is with a Medicare redesign is an acceleration of patients choosing to receive Hytrulo at home even before PFS. This underscores the need we will be filling with PFS self-injection that it will expand the market. So in terms of the magnitude of a gross-to-net, we can't get into more detail now. We will provide probably more detail at the end of Q2, but you did see an increase in gross-to-net. But the majority of impact you're referring to is to do a seasonality relating to the reverification of benefits. That is an industry benefit -- industry impact which you always see. Maybe, Karen, do you want to talk about that?

Yes. Thanks, Karl, I think that's really clear. And I think that's important to note. What we saw in Q1 is similar to what we saw in Q1 last year and the normal industry dynamics of seasonality related to benefit reverification and impacting the volume. But remember, VYVGART is a growth story. We saw growth in Q1. We had the PFS approval in Q1 and what we expect to see is continued growth and continued cadence of growth through the remainder of the year as we continue to launch PFS for both MG and CIDP.

Your next question comes from the line of James Gordon from JPMorgan.

The question was most favored nations has come into focus again, and there were some concerns around different list prices with VYVGART in different places. So can you remind me how VYVGART list price varies between the U.S., EU and Japan. And also, have you already set the PFS price outside the U.S.? So how the list price varies there? And if I could also just ask a follow-up question. So as it has been discussed, some impact this quarter from patients shifting to Part D and that comes in with a catastrophic discount from the company. But looking to Q2 and the rest of the year, are you seeing significant further incremental headwinds from this Part D shift and then holding net price that we need to be wary of when we're thinking about Q2 and the rest of the year? Or is one way of thinking about it looking at the phasing we saw last year in 2024, where Q1 was a bit softer sequentially within Q2 saw quite acceleration because you didn't have the recertification headwind. And then you've got PFS coming in and you've got more CIDP coming in. So should we look at last year's phasing for a bit of a guide for what this year's phasing looks like?

Okay. Thank you, James. I think you asked three questions. So let me take them one by one. First one is on most favored nations. We have been very disciplined and aim to keep a less price in all our markets within a narrow band. For example, we have the launch of VYVGART in Germany, where less price was set very close to the U.S. list price. Prices evolve, of course, over time due to foreign exchange, labor expansion and so forth. But that said, we have done a good job in keeping the list prices in all our priority markets in a narrow band. On your second question, the PFS pricing have been set in all our priority markets. So I think that's done. Your third question, I think, in terms of Q2, I think it goes back to what Karen has said that PFS is an expansion strategy, which will create -- which will give us more prescribers and more patients. But yes, gross to net will also increase quarter-over-quarter as the product mix between medical and pharmacy changes.

Yes. And I'm just going to add, in terms of the rebound effect that you mentioned, I wouldn't think about it like that, would zoom out. And what you can see when you look quarter-over-quarter since the beginning of the launch of VYVGART. When you take a line through it, it's relatively consistent growth quarter-over-quarter. So we don't look at the ups and downs each quarter, but rather I'd encourage you to take that line through it and look at the long-term trajectory. And we're confident that, that consistent growth will continue over the long term.

Your next question comes from the line of Derek Archila from Wells Fargo.

Just wanted to see, given the ADAPT-NXT publication and the data set there, are you assuming increasing number of treatment cycles in MG patients as part of your growth calculation to offset the Part D exposure?

Thanks, Derek. Thanks for the question. If you look at the material consumption between ADAPT-NXT or cyclical dosing, actually, net-net, you end up using the same amount of material. So we do not believe this is going to materially impact the dosing of VYVGART. I think what is really important about ADAPT-NXT is that now we have taken the individualization to the end. Now each patient can dose the drug the way it should be dosed from cyclical to continuous dosing. So now we can offer the full spectrum. We are very proud of the data at AAN I think we showed impressive efficacy data from ADAPT-NXT with a 56% MSE, spick-and-span safety profile and real nice continuation over 126 weeks of use. Thank you for your question.

Your next question comes from the line of Yaron Werber from TD Cowen.

Maybe, Karen, just a question for you on CIDP. Is there any chance you can give us a little bit of a sense how many patients did you have during the quarter or finished during the quarter? And then sort of related to that, at AAN, there was a publication, right, that looked at safety in CIDP and you had just over 1,300. I think it was 1,316, real world patients on VYVGART at that point. Can you triangulate that maybe to again your commercial patient numbers on CIDP?

Yes. Thank you for the question. We're not updating that number at this moment. What we'll do in the style of what we've done for other launches is update the number as we hit different milestones. But what I would say, again, just zooming out is we have had consistent patient adds quarter-over-quarter and consistent prescriber growth in CIDP. We've also seen consistency in where the patients are coming from. And what I mean by that is 85% to 90% of the patients continue to be switched from IVIG or subcutaneous IG to VYVGART. And that's exactly in line with where we thought we would be at this moment in launch and with the 12,000 in Japan. So we think we have a long way to go in terms of our growth. We're just at the start of the growth trajectory with the CIDP launch. And certainly, PFS will be a strong driver of that continued expansion as we continue to launch PFS through the year.

Your next question comes from the line of Victor Floch from BNP Paribas.

Great. So I was just -- I mean, obviously, there's been a lot of focus on the price implication of the PFS ramp-up as at the Part D product. But at the same time, I think it would be helpful if you could share with us your expectation in terms of incremental volume attached to the PFS opportunity. I mean I think you've notably said that you were basically not following a conversion strategy. So I mean you're looking to add patients. So I mean, I think we tend to look at the pain right now. We tend to look at the implication on the price. But I mean, what are your expectations in terms of volume growth tied to the PFS? And my follow-up is very much close to the first one. It's about the seronegative Phase III trial. I mean a lot of -- I mean, investors have been pointing pretty light news flow over the -- for the next part of the year. I mean there is the Phase III in seronegative and maybe for some of them is seen as a given. But I mean, it would be nice if you could share your views on the opportunity in terms of incremental volume and potentially sales there because, obviously, it's not nothing to grow the addressable opportunity from 80% to 100% of patients, even though I agree that I mean it's fair to say that the risk is pretty low. But yes, any comment on the volume would be super helpful.

Yes. Thanks for the question. I'll take the first one, and I think Tim will take the second. So I would say, we're confident about PFS driving significant volume growth both for MG and CIDP. I would say we got the optimal label, and I would like to say huge congratulations to the team. I mean when you look at 20 to 30 second injection time, no specific monitoring or training requirements, these are all features, but the benefit that we see and that we hear from patients are that they are completely free from the office. We hear that they're excited. You heard in the script that patients are describing this as a game changer in terms of managing their MG and CIDP. So as you said, this is a market expansion opportunity for us. What we're seeing in the early data is that 50% of the PFS prescription new to VYVGART patients. So they're not converted rather they're overall new to VYVGART, and that's exactly in line with this market expansion strategy. So if you zoom out, what we're looking to do in both MG and CIDP is bringing new innovation and patient-centric innovation to the market and we're seeing this exactly in PFS, and that's what's going to drive the long-term growth trajectory for both of those indications. And then maybe further seronegative and the news flow, Tim, do you want to take that?

Yeah. I think Victor, you're right, calling out the news flow for this year, which I think is strong with 1 Phase III readouts and 3 Phase II readouts this company is in a strong position from a news flow point of view. So the Phase III readout in seronegative myasthenia, the Phase II in lupus nephritis for efgartigimod, the Phase II in delayed graft function for empa and then the Phase II proof-of-concept in CMS for 119. Specifically on seronegative MG, I think we are very excited about the opportunity in front of us. You have to think about 15% of the overall MG patient population, which falls in the seronegative basket. We do know from Japan that we have seronegatives on label that VYVGART is offering the same benefit risk profile to seronegative patients as it does to the acetylcholine receptor antibody patients. So very strong performance. Now it's all about the design of the experiments. We have been learning and triangulating with the FDA on the endpoint for this clinical trial. We think it's a solid clinical trial, and we feel very strong about the opportunity in front of us. Let me end by calling out our excitement about ocular MG, which I think is equally in size and unmet medical needs. So opportunity would be equal in ocular MG as in seronegative MG.

[Operator Instructions] Your next question comes from the line of Tom Smith from Leerink Partners.

This is Nat Charoensook on for Tom Smith. So following the approval of pre-filled syringe, what's your expectation on the split among uses of the 3 product presentations of VYVGART including VYVGART subcu, Hytrulo and pre-filled syringe in MG and CIDP? And similarly, how do you expect the payer mix to evolve following the...

Thanks for the question. So what we're seeing already with the launch of Hytrulo, is it the majority of growth in patients -- in new patients for MG and CIDP is coming from Hytrulo. That was even with the butterfly execution, and we expect that will continue and even accelerate with pre-filled syringe. Again, we're hearing from the market that people are really excited and that it really is a game changer having pre-filled syringe for self-injection available for patients. So we think that will be a growing portion of the market. Karl, do you want to take the question around the payer mix. I mean, I know we've shared in the past that 50-50 commercial Medicare, and I don't think we expect that to change significantly.

Yes. No. I mean, I think that is what it is today, and I'm not expecting changes. We'll keep give you updated if it does.

Your next question comes from the line of Akash Tewari from Jefferies.

This is Amy on for Akash. So one, is your fill finish and better considered substantially transformative? And if needed, how quickly could you move that into the U.S. And then just a theoretical question on MFN. What mitigation measures could you potentially employ? Could you price your PFS differently ex U.S. It's a different product code? And would you consider pulling some of the other formulations?

Thanks, Amy, for two questions. The first one, in terms of substantial transformation, I would use the drug substance manufacturing as your guide here and the drug substance manufacturing, of course, is taking place on U.S. territory. Secondly, Karl already explained that I think we're in a strong position from an MFN point of view because we have shown the discipline in the way we have been maintaining -- setting and maintaining price in a narrow band globally in our key markets. So let's stay away from speculation. But I think we have strong cards to navigate whatever the future will bring us on these 2 fronts.

Your next question comes from the line of Charles Pitman-King from Barclays.

Just a question on kind of Part B, Part D movements. If you could just give us a little bit more insight on what the actual price differential is between a Part B and Part D patient over 1Q. I think that would be very helpful. And then just kind of following on from that, thinking about the kind of future split of patients, I mean, I think you kind of highlighted PFS is expected to become an increasing proportion going forward. But given you've already been seeing these Part B patients move to Part D in the $2,000 co-pay related to the redesign, like how do you expect IV to grow from here? Or should we expect -- like what's the future split of the 3 administrations?

I mean, at a high level, the difference between the net price for a Part B and Part D would be the 20% incremental rebate which we have to pay and the Part D to CMS patients who are on catastrophic. So that's at a high level difference between the two. In terms of the presentations going forward, remember, we said that in the U.S., we think IV will always continue to be important for the U.S. market. Think of a buy and bill customers, physician preference and so forth. But over time, from where we are today and today, we already have a minority, but we already have Part D patients over time, but mix will increase and you're going to see a greater proportion of the patients in Part D.

Your next question comes from the line of Myles Minter from William Blair.

Just on VYVGART Hytrulo use in CIDP, I think you mentioned 85% to 90% of those patients were switch patients. Can you just comment on the incidence of CIDP disease worsening when you make that switch? Just wondering if you have any real-world data. I think someone has presented it at AAN.

Yes. Thanks, Myles, for the question. So -- and I referred to the great conversation we had with Dr. Karam in the panel conversation during AAN. The first thing you need to know in CIDP is that whatever switch you consider to do, be it from steroids to immunoglobulins or vice versa or the VYVGART, there's always an expectation and the possibility that the patient will relapse. So this is a fact you also see that in the IVIg, subcu IG switch studies. I think the symptom worsening, which we have seen in the context of the MG trial is perfectly in line with those historical studies. And in the real world, that it's a relatively small phenomenon, we see low single digits reporting on CIDP worsening. So the vast majority of our physicians are doing it the right way. It seems like switching to VYVGART 1 week after the last dose of IVIg is a recipe for success, but we're trying to document that in our Phase IV and switch study where we really try to collect evidence on how to switch best. So it is a non-phenomenon in CIDP, and it looks like we are navigating that quite well.

Your next question comes from the line of Suzanne van Voorthuizen from Kempen.

This is Suzanne. Could you please elaborate a bit more on how you look at empa relative to VYVGART in CIDP given the pivotal trial for empa is different than what you did for VYVGART. Can you share how are you thinking about the positioning of each product and comment how the commercial opportunity looks like for each molecule in this indication, perhaps relative to each other?

Thanks, Suzanne. Thanks for being with us and thanks for the great questions. So CIDP is a heterogeneous disease. I think the ADHERE trial, which was the biggest and the highest quality trial ever done in the CIDP space is clearly demonstrating that pathogenic IgGs drive disease at least in about 70%, 75% of the patients. The question is then why do the other patients not respond. There is a suspicion that complement is in play through pathogenic IgM antibodies. And we have pretty strong translational data in hand for EMPA in CIDP. Now we do not want to niche EMPA into kind of refractory setting only we really want to give this great molecule, the fullest chance of success in the CIDP setting. So that's why we have designed the clinical trial, you all see and let the data speak, I think this is a significant market, a significant opportunity which can harbor multiple innovative molecules to optimally address the patient needs. So let the data speak now. Thank you for the question.

Your next question comes from the line of Yatin Suneja from Guggenheim.

Question is on the gMG side. Could you just talk about the relative penetration in the targeted patient population you have achieved. Also, I think in the past, you have said that at least in myasthenia gravis, you are consistently seeing $40 million to $50 million worth of quarter-over-quarter growth. Is that the same -- is that what you are seeing now? And how should we think about the growth just purely in the gMG? And any impact or some competition, whether it's the CD90 or anything else that you might be seeing or complement?

Yes. Thanks for the question. Always appreciate being able to talk about MG growth, 13 quarters into launch and the fact that we're still delivering that consistent cadence of quarter-over-quarter growth. And to your question, I would say it is -- we are seeing consistent penetration into the earlier line. I mentioned that before. More than 60% of our patients are coming from earlier lines. And what we're seeing as part of that is that the share of the market treated by biologics is growing substantially, and VYVGART is leading growth. We have the #1 market share. We're growing that #1 market share in all of our major markets. I would say, at the early stages in terms of penetration, we updated the TAM to 60,000. You'll recall last year, and with that, I think you can see that we're on the -- in the early stages of the growth curve for MG, even though we're 13 quarters into the launch. And what we can -- what you can expect and what we expect is consistent and continued growth in whether you look at new patient starts, at prescriber growth, all the metrics that you mentioned, which is revenue growth when you take a line through it since launch I think we've been delivering that consistent growth on average since launch, and we expect that to continue. Tim, did you have something to add?

Yes, Karen. And you can please see that we have broken out of the refractory patient population, right? What it takes to really move first line and lead in the first line is the clean safety profile, which we have demonstrated for the drug. Remember what we said in the prepared remarks, no black box, no need for vaccination, no lapse, no monitoring. That's a very powerful profile to go front line as a biological. And what we see, right, Karen, is that about 60% of the new patients coming on drug comes straight from the orals. And that is where the growth opportunity is in front of us, and we think PFS will continue to fuel that.

Our next question is from the line of Andy Chen from Wolfe Research.

And back to the topic of most-favored nation. So Karl, I understand that you talked about a narrow band. And just wondering if that narrow band is less than the 20% discount that you will have to pay on Part D or is it more than the 20%. Just curious if there's a way for you to push your patients to the Part D to minimize exposure just because Part D price cut is less likely than a Part B price cut if most-favored nation comes to play.

Andy, I think I don't want to talk about percentages, but I think the reference to most-favored nations here on list prices. And I think in list prices we are in the narrow price band. And I think we shouldn't -- I don't want to speculate on way below and it's still in concept phase. So what -- so for now, I think I'll stop there. But maybe, Tim, you want to add something?

Yes, we're not in the business of pushing patients into certain directions. I think what we're trying to offer is the broadest product offering possible to satisfy the needs of the different patient segments. So I think what you guys are seeing in Q1 is a very strong appetite of patients to move into self-administration at home or product administration at home. That's why this acceleration under Medicare Part D is coming. But guys, this is the force you need in order to spectacularly grow your market. So following the patient demand, satisfying the demand is the best way for growth going forward. And I think you basically see a signal here that patients are eagerly awaiting the PFS.

Your next question comes from the line of David Nierengarten from Wedbush Securities.

I have one question which is, are the dynamics as you see patients getting treated with ocular MG currently? Are those dynamics different from generalized MG and how that might affect your commercialization plans and duration of treatment, things like that in that potential expansion?

Yes, David, we don't want to squeeze you, right? I mean your question is valuable to us. Ocular MG, high unmet medical needs, which we overlooked in the beginning when we were approaching the MG market. It's very debilitating to have ocular MG. There's no ability to work on the screen, drive a car, there is a big social stigma associated with the symptoms, et cetera. So, the truth is that today, the toolbox to treat these patients is even more limited. You would typically see that these patients are being treated with mestinon and a high dose of corticosteroids. We know what the detrimental effects are of high-dose corticosteroids. We know what the detrimental effects are of high dose corticosteroids used chronically. And we're really on a campaign of steroid tapering. We have a strategic alliance with Steritas. We think the moment has arrived to actually offer these patients a real alternative with the benefit risk profile of VYVGART. So high unmet need, very limited treatment toolbox and an opportunity to disrupt that treatment paradigm.

Your next question comes from the line of Gavin Clark-Gartner from Evercore ISI.

Apologies, but it's one more net price question. For the pre-filled syringe, what are your current assumptions for the number of payer contracts that will include VBAs moving forward, specifically wondering on the CIDP side. I'm wondering if this could offset the gross-to-net a little bit.

Yes. So maybe just to start before I hand it over to Karl. To take a step back and remind everyone that our strategy with VYVGART is to provide as broader access as possible to patients. And certainly that we don't want them to be choosing between product presentation based on price. We want them to have access and be able to choose the product presentation that fits into their life. So that's the strategy that we're pursuing. And what we've seen, whether it through the MG launch, the CIDP launch and what we expect with the PFS launch is that our market access team, our experts are getting really good access in place quickly for patients. And we expect that will be the same and the agreements will be signed quickly to get that access in place for pre-filled syringe. But Karl, did you have anything else to add on the details.

I mean Karen, I think the only thing I will say is that generally, VBAs are less important in the pharmacy channel than the medical channel. So I think we'll leave it at that, and we -- let's negotiate the contracts during the next few weeks...

Your next question comes from the line of Samantha Semenkow from Citi.

Another one on CIDP. I'm wondering how has the discontinuation rate in CIDP trended? Are you still seeing physicians giving the majority of patients a 12-week trial? Or has that trended down as they gain more experience with VYVGART in this population?

Yes. Thanks for the question. So in terms of CIDP, we are still seeing that doctors are giving that 12-week trial. And what we've seen as the launch has matured, is that there has been a little bit of an uptick in discontinuation more towards we'd expect based on the ADHERE trial, but there is still a significant gap. And I would say we're below that discontinuation rate. So what we're seeing is patients starting on VYVGART, having a positive experience and staying on VYVGART.

Your next question comes from the line of Leland Gershell from Oppenheimer.

Great. Just 2 from us if we can. Just with respect to the upcoming data from the switch study from IV to VYVGART in CIDP. Just given the dynamics there and the positive launch. Just wondering how critical do you see those data for physicians to effect a switch in their patients. I also want to ask with respect to 119 later this year, we'll see the POC data in CMS. There are a few clinical end points being looked at. Just wondering if you have any threshold in mind when you look at those data for taking that program forward in CMS.

Yes. Thank you for the 2 questions. So the significance of the IVIG switch study is very simple. I think the ADHERE trial was a very ambitious trial, but there is only so much you can answer in one clinical trial. So we addressed that this is an Ig-driven disease, we addressed the magnitude of the effects you can show across the board in CIDP patients, but we did not really study in detail the switch dynamic. Remember, patients had to worsen so they could demonstrate active disease before they came on trial. That is a bit of an artificial experimental setting. The Phase IV trial is now investigating a practical question, how do you really switch in IVIg or SCIg patients to VYVGART, a simple trial design. It's a Phase IV, and it's meant to give some practical handle to treating physicians on how to do the switch. So I think it's an important data point. With regards to 119 molecule, which is very close to my heart, congenital myasthenic syndrome, what we learned about these patients in the natural history study is that they actually look very much like the autoimmune myasthenic patients. There is a very strong fatigability aspect to that disease. Limb-girdle is really affected. So weakness of the shoulders, weakness of the hips. And therefore, we're really testing a menu of endpoints that just testing which ones are really, truly capturing the nature of the disease, the classical ADL and QMG measures are in there. And we know what the clinical thresholds are for clinical relevance. So we will be looking through that lens at our patients, and we will inform you, of course, when we have the data in hand. Thank you for the question.

Your next question comes from the line of Joel Beatty from Baird.

Just kind of a longer term one, I know the PFS rollout is just taking place. But have you started turning your attention a little bit now to firming up time lines and strategy regarding the auto-injector?

Yes. Thanks for the question. I appreciate zooming out and looking over the long term. And yes, our team is consistently working on the -- not just auto-injector but how we can innovate for patients overall. In terms of the auto-injector, we continue with that development plan though latest update we have provided is that we're moving it into being able to understand how to produce it at larger capacity. So everything is on track, and we look forward being able to bring continued innovation to patients in the future.

And your last question today comes from the line of Xian Deng from UBS.

So really, thank you for the comment on European and U.S. have very similar list price. But just wondering, could you give us some color on the sort of difference in terms of the net price, please? I'm sort of asking in relationship to how should we think about the commercial opportunity for PFS in Europe because on one hand, Europe does have this kind of lack of IV infrastructure compared to the U.S. But then on the other hand, probably, we have probably less net price. So how should we think about that, please?

Yes. Thanks for the question. And maybe to start with -- I'll reinforce something that Karl has said. In terms of our ex U.S. expansion, we've taken a very disciplined approach to ensure financial sustainability as we provide access to patients around the world with VYVGART. So I think we're very well positioned in terms of our net price from that perspective. And you're exactly right. We see the PFS opportunity as a big opportunity ex U.S. because of the hospital dynamics that you mentioned. We've already seen the first patient dosed in Germany. What we saw with the Hytrulo butterfly execution is a very fast conversion in Europe, in particular, of patients from IV to the butterfly execution of Hytrulo. And we think that will accelerate with PFS and will certainly help to accelerate and continue our growth in rest of world or outside of the U.S. in the future. So we're really excited about the opportunity for PFS, not just in U.S. but around the globe with launches coming. Thanks for the question.

And this concludes today's conference call. Thank you for your participation. You may now disconnect.