Biogen Inc (BIIB) — Q1 2026 Earnings Call Transcript

Well, thank you, and good morning, and welcome to Biogen's First Quarter 2026 Earnings Call. During this call, we will make forward-looking statements, which involve risks and uncertainties that may cause actual results to differ materially from our forward-looking statements. We provide a comprehensive list of risk factors in our SEC filings, which we encourage you to review. Our earnings release and other documents related to our results as well as reconciliations between GAAP and non-GAAP results discussed on this call can be found in the Investors section of biogen.com. We've also posted the slides to our website that will be used during the call. On today's call, I'm joined by our President and Chief Executive Officer, Chris Viehbacher; Dr. Priya Singhal, Head of Development; and Robin Kramer, our Chief Financial Officer; Alicia Alaimo, President of North America, will also be joining for the Q&A section of the call. We'll make some opening comments and move to the Q&A section and to allow us to get through as many questions as possible, we kindly ask that you limit yourself to one question. And I'll now hand the call over to Chris.

Thank you, Tim. Good morning, everyone. So we've had a very strong start to the year. And I was thinking about where we have been as a company in 2023, we had just completed four years of declining revenue and profit. And since then, we've been able to pretty much stabilize the business. And that's really been a huge amount of work by all of our teams. And the interesting thing about this business is it's not enough to just trim some cost, and we did have to cut some excess cost. But one of the things that we have really been doing is going through every single line of the P&L and thinking about are we investing for growth? Because you do have to invest in this business. You cannot save your way to prosperity. And so there's been a lot of really careful thought about how do we invest for growth, be it in research and development or in commercial. And as Robin has talked about in the past, we actually have shifted a lot of costs. Ninety percent of our commercial costs were really behind the MS portfolio in 2023. And by shifting that to our growth products, I think one of the things you see here on the first slide is that the growth products are now generating $850 million in the first quarter, and that's up 12%. And the 12% is actually even a little bit of an understatement because SPINRAZA declined slightly. Now SPINRAZA declined mostly because of the timing of shipments and there was a one-off event last year on VAT in Europe somewhere. But remember, timing of shipments is a big thing at Biogen. Out of the 15,000 patients on SPINRAZA that we treat every year, about 9,000 are ex-U.S. And in a lot of countries, we only ship once or twice a year into those countries. So it tends to be lumpy by nature. What is good news is the new high-dose SPINRAZA. As you've seen, this has now been approved in the U.S., and we already have patients on the new dosage regimen. But it has already been approved in Japan. It was the first country to approve the high dose. And then Europe, and we're getting a lot of positive feedback from those countries where it's been launched. Not only is this going to be significant in terms of competitiveness in a highly competitive area, but we're also seeing some anecdotal reports of switch-backs. In this market, whenever you have one of these devastating diseases, efficacy is really paramount. And I think the high dose really should help us have an edge on the efficacy front in this market. So we're very happy to see the growth products growing like that. We look to our major opportunity with LEQEMBI and as you know, over the past few years since launch, a lot has been done to try to improve the care pathway, make it easier for both physicians and patients. And the IQLIK is really fundamental to that. Last year, we had the approval for the maintenance indication — and you'll see numbers where we have significant numbers of patients who are continuing on after the first 18-month regimen to remove the plaques and going on to maintenance. We have a PDUFA date of May 24 for the induction subcutaneous. And again, we see this as an opportunity to facilitate the care pathway, improve patient convenience and improve our competitive profile versus gantenerumab. So that's the business, the Biogen business is doing well. And now on top of that, we are the proposed the Apellis acquisition. We haven't yet closed, so we're limited in what we can say. But obviously, this expands our commercial growth portfolio. There are two marketed products. And I'll just remind everybody that this is one molecule. It has three indications, and it has two brands. And as I talked to a number of investors on SYFOVRE, there is this focus on ophthalmology. And what I think a lot of people forget is that geographic atrophy is really an autoimmune disease. And it is caused by the formation of lesions as a result of aberrant immune activity. And what we're really trying to do with geographic atrophy is to prevent the growth of these lesions. So when people start talking about visual acuity, that's probably going to be very difficult because the eye tends to adjust around these lesions. And what really is the goal of treatment is to prevent progression of the disease, which could potentially lead to blindness. And so I think there's a lot that we need to do in terms of thinking about how we really position this drug and where the benefit is. Empaveli is an enormous benefit to us. We have greater conviction every day on felzartamab, and we look forward to seeing the first data and hopefully those data will realize our aspirations for this product. But if you went back six, seven years ago, nobody was interested in nephrology. And now really with the advent of the FDA acceptance of proteinuria as a biomarker, a lot of companies have come into this space. IgA nephropathy is obviously the biggest market in this area, and so as we think about recruiting for felzartamab and our prelaunch activities, you're finding that you've got a lot of companies out there that are recruiting in nephrology. I mean, Vertex, Vera, just to name a few, for example — and so within the nephrology area and with the addition of the Apellis team, we have a whole team ready to go in nephrology, and we'll be present in the nephrology offices, building those relationships, going to congresses now with a marketed product, not a future product. And so we believe both in the growth of Empaveli, but what that can do for a whole nephrology franchise at Biogen, and we're pretty excited about that, I have to say. And I think all the conversations that we've been having with the Apellis team leading up to a potential integration, I think there's — first of all, there's an incredible talent in the Apellis team. But I think it's also fair to say that within Biogen, I think we can probably bring more resources to really support those teams. And I don't see a big inflection in SYFOVRE, for example, but I do think there is an opportunity for growing product there. And I think, as I say, Empaveli within a broader nephrology franchise, that could be a game changer for Biogen in the future. So as we look at this, we do expect the acquisition to be accretive in 2027. And when you look out over the next few years, this materially increases Biogen's EPS outlook. And if I turn to the next chart here — now don't get your micrometers out here and try to measure these arrows here, this is meant to be illustrative of where we think this is going. If we just take what Wall Street thinks Biogen is going to do, I can't say that we would be happy with that, but that's what's out there in the public domain. It's roughly flat through 2030. Now when you look at what Apellis can do is this allows Biogen to start growing now is our belief. And then the pipeline starts to read out. We've got a lot of data readouts already starting this year and consecutively over the years. And as one investor told me said, I get this: before we had a pipeline coming on a flat business. Now I see a pipeline coming on a growing business. And I think that's the fundamental difference in what the Apellis acquisition does for us. And we're still going to continue to do business development. In all of this, we just acquired the China rights for felzartamab; that's an important market for IgA nephropathy, but China is a big important market for us. And Biogen has been relatively small in China. China is the world's second-biggest pharmaceutical market and so felzartamab and acquiring these rights not only just to acquire the worldwide rights for felzartamab, but also really to build our business in China. So again, we continue to invest in growth, but I think a lot of the investments, a lot of the work that we have done over the last two, three years is now coming to fruition. And at least this is the vision. Now we are very conscious of the fact that business ten percent is strategy, execution. And so we need to now execute as a team to bring all of this, but at least this is the aspiration that we have for our company. With that — let's talk about that pipeline, and I'll pass it to Priya.

Thank you, Chris. This was a very strong quarter for Biogen from a development standpoint, with meaningful progress across both our marketed products and our late-stage pipeline. Starting on the left-hand side of the slide, you can see the continued progress in supporting our marketed portfolio. First, the U.S. approval of high-dose SPINRAZA represents a meaningful advancement for people living with SMA and reinforces Biogen's leadership in the category. Additionally, in Alzheimer's disease, new real-world data for LEQEMBI show strong treatment persistence with nearly 80% of patients remaining on therapy at 18 months and almost 70% at two years. We believe that these data underscore the importance that patients and HCPs attribute to ongoing treatment of this progressive disease, extending beyond just amyloid plaque reduction. Turning to the right-hand side, we presented important new data that reinforce the potential of our late-stage high-conviction pipeline. New data from Salanersen demonstrate durable benefit over one year in children previously treated with gene therapy, highlighting the potential for high efficacy with one yearly dosing. Importantly, the first patient has now been dosed in the pivotal STELLA-1 study evaluating Salanersen in treatment-naive symptomatic infants. At the same time, we continue to build confidence in Litifilimab, where we presented positive Phase II data from the ongoing Phase II/III AMITA study in SLE. All of this progress reinforces our confidence in our late-stage pipeline. And as you can see from this slide, we don't expect to wait long for that potential impact. This year marks the start of a multiyear registrational data flow that includes multiple programs and extends through the end of the decade. We believe these data, as you also heard from Chris, will continue to strengthen our growth outlook. And importantly, as previously reflected, we have several data-related inflection points in 2026. We, as you know, have a PDUFA date coming up for our LEQEMBI IQLIK initiation next month. We also have readouts from our pre-proof-of-concept pipeline, where we continue to pioneer and address key scientific questions that could benefit patients. Our registrational readout cycle begins later this year. And over the next 18 months, we expect to see SLE and CLE data from all the Phase III studies of Litifilimab as well as readouts from the first Phase III study of FELZARTAMAB in AMR and the Phase III study for ZOREVUNERSEN in Dravet syndrome. I believe this is a very exciting time for the Biogen pipeline. I would now like to turn the call over to Robin for an update on our financial performance.

Thank you, Priya. I'd like to start with key highlights from our strong first quarter 2026 results. Total revenue was $2.5 billion, up 2% year-over-year with GAAP diluted EPS of $2.15, up 31% year-over-year and non-GAAP diluted EPS of $3.57, up 18% year-over-year. We're pleased to see our growth products continue to perform well generating $851 million of revenue, up 12% year-over-year. Our growth products, which includes VUMERITY, generated more revenue in the first quarter of 2026 than our remaining MS products. We also maintained our cost discipline while supporting our late-stage pipeline development and product launches with approximately $1.1 billion of non-GAAP core operating expenses in the first quarter of 2026. As a result, we generated $594 million of free cash flow in the quarter, allowing us to further support the business and invest in future growth, including the expected Apellis transaction, which we believe represents a capital allocation opportunity that will further bolster both our top-line and bottom-line growth prospects in therapeutic areas aligned to our immunology and rare disease strategy. I'll speak more about the transaction in a few moments. I'll now turn to our revenue performance for the quarter, starting with our growth products. LEQEMBI market revenue was $168 million for the first quarter of 2026, up 74% year-over-year. We saw a continuation of sequential market growth in key markets, including the U.S., Japan and China. In China, we saw strong uptake with Q1 reflecting continued demand growth and sequential revenue benefited from completing the drawdown of inventory in Q4 2025. LEQEMBI remains the market leader by total patient share in the U.S., Japan and China, and we look forward to next month's U.S. PDUFA date for IQLIK initiation. SKYCLARYS saw sequential global patient demand growth with first quarter 2026 global revenue of $151 million, representing 22% growth year-over-year. For SKYCLARYS, U.S. revenue was impacted by the inventory dynamics we discussed on the Q4 2025 call with moderate growth in demand. Outside the U.S., we continue to see demand growth as we continue our SKYCLARYS launch. SKYCLARYS is now available in 35 countries and we continue to expect SKYCLARYS growth to come from ex-U.S. as we advance the launch. Now turning to the highlights of our key P&L items for the quarter. Non-GAAP R&D expense in Q1 2026 was $480 million, with the increase year-over-year reflecting investments in our Phase III clinical programs including felzartamab and Litifilimab and the phasing of spend within the year. Non-GAAP SG&A expense in Q1 2026 was $600 million with the increase year-over-year reflecting planned prelaunch activities supporting lupus and nephrology, direct-to-consumer advertising for VUMERITY and ZURZUVAE and due to phasing of spend within the year. First quarter 2026 GAAP and non-GAAP effective tax rates were 15.4% and 15.3%, respectively. The year-over-year decrease was due to favorable impacts from a foreign tax settlement and vesting of certain share-based awards, partly offset by the increase in U.S. taxation on foreign earnings in 2026 under the one big beautiful bill approach. And as we previously announced, we recorded approximately $34 million of acquired IP R&D in the first quarter of 2026, related primarily to our AltiGen and Alloy transaction, resulting in an approximately $0.20 per share impact to GAAP and non-GAAP EPS. As a reminder, in the first quarter of 2025, we recorded $165 million of acquired IP R&D associated with the upfront payment to Therapeutics as part of our collaboration for ZOREVUNERSEN for the treatment of Dravet syndrome in all the territories outside the U.S., Canada and Mexico, resulting in approximately $0.95 per share impact to GAAP and non-GAAP EPS. This strong commercial execution, coupled with disciplined financial management drove continued robust free cash flow performance. We generated $594 million of free cash flow in the first quarter of 2026 and exited the quarter with $4.7 billion of cash and marketable securities and $1.5 billion of net debt. With the Apellis transaction expected to close in the second quarter of 2026, we plan to fund the transaction with $3.6 billion of cash from the balance sheet and $2 billion from bank borrowings. Given our expected strong cash flow generation, we expect to repay the $2 billion in new borrowings by the end of 2027. Given the dynamic policy environment, we have updated the slide we first provided you this time last year. We continue to believe the structure of our U.S. manufacturing footprint, supply chain and overall business model position us to be potentially more resilient to macroeconomic factors and policy uncertainty. Currently, based on potential tariffs as announced to date, we do not expect to see a material impact to our business in 2026. This information does not reflect the impact of the pending acquisition of Apellis. Turning now to guidance. Our overall belief in the strength of the underlying business is as strong as when we guided in February. We also continue to believe it's important to make investments for growth. In addition to the roughly $0.20 EPS impact from the acquired IPR&D charges we incurred in Q1, we also expect to incur $145 million or an $0.80 EPS impact of acquired IPR&D charges in the second quarter. Specifically, the TJ Bio transaction for felzartamab rights in China, which further enhances our nephrology franchise and gives us worldwide rights to felzartamab is expected to comprise $0.55 of the EPS impact. As Priya noted, we also achieved the first patient dosed in STELLA-1, our pivotal Phase III Salanersen study, triggering a milestone in the second quarter, which results in approximately $0.25 of EPS impact. Turning to some key considerations for this updated guidance. You can see that our expected business outlook and underlying assumptions, including our revenue outlook remained consistent with our prior guidance. As I mentioned earlier, we expect roughly $600 million of contract manufacturing revenue this year to be phased as roughly two-thirds coming in the first half of the year. We expect Q2 core operating expenses to be roughly consistent with Q1. It remains our objective to be disciplined on costs as we continue to invest including supporting the programs that we've been bringing into our pipeline through business development. Please be sure to review this slide and our press release for other important full-year 2026 guidance assumptions. And finally, a few points on the expected impacts from the Apellis transaction. The transaction is not yet closed, so we won't provide consolidated guidance today. That said, we do plan to provide 2026 guidance inclusive of Apellis when we report second quarter results following the transaction's close. We can say today that we believe we will be getting two best-in-class commercialized medicines that enhance our growth portfolio. We believe Syfovre and Empaveli will contribute meaningfully to our top-line growth in the near and long term. We expect approximately $120 million to $130 million of impact to our non-GAAP and other income expense line in 2026 driven largely by financing and foregone interest income. We expect that our strong combined cash flow generation will provide us with the opportunity to delever by the end of 2027 and that the transaction will be accretive to non-GAAP EPS in 2027. We believe this transaction represents an attractive use of capital that will further bolster both our top-line and bottom-line growth prospects in therapeutic areas aligned to our immunology and rare disease strategy. With that, I would like to pass the call back to Tim to open us up for questions.

Thanks, Robin. Can we go to our first question, please?

Congrats on the quarter. As we look towards the upcoming BIIB080 data, I'm curious to your latest views on what kinds of signals you'd be looking for there to move forward? And how much would that be impacted by your expected potential to further improve the administration form there?

Priya?

Thanks, Brian. Just stepping back, BIIB080 is an antisense oligonucleotide. It addresses tau and aims to reduce tau — and we've seen that in prior trials, an extracellular approach using an antibody has really not worked. And so that's where the ASO approach is differentiated. We believe it could target both intracellular and extracellular tau. We did see tau reduction in our Phase Ib, which was a small trial, which is very encouraging, which prompted us to get to a proof-of-concept study. And that is what the CELIA readout will tell us. Because this is a pioneering effort and what we're looking to see is whether reduction of tau leads to and translates into a clinical benefit, specifically on cognition. But as we do that, we're exploring several dosing regimens, several treatment frequencies. So we'll be looking at the totality of data. We're expecting the data sometime midyear and I think our goal would be to look at the data and then communicate it and present it at upcoming forums. So that's the plan.

And on the dosing regimen?

Yes. On the dosing regimen, I'd like to say that really, the trial enrolled very quickly from an enrollment perspective. We recognize that if this actually translates into a medicine we would be considering other options. So we are looking at other options of delivery. These are in preclinical and research and we recently acquired Alcyone as you know, and that gives us another potential avenue to explore if and as we continue with implicit delivery.

So as we think about your other catalysts for 2026, just wanted to ask on LITIFILIMAB actually in the filing strategy. Would you guys consider filing for SLE right away if both Phase IIIs were positive later this year? Or would you wait to file after the other to file one or two NDAs? And then if just on SLE study hits that big, but the other one was trending, would you still file in that SLE?

Thank you, Andrew. We are excited about the potential for Litifilimab. We have two Phase III trials in SLE. We expect them to read out this year, we accelerated the second trial and we are really doing well on our CLE trial. We expect that to read out early next year. Now with regards to the filing strategy, we don't usually comment on it, but I'd like to say that we think that this would be a package as of now, and we'll communicate more as these studies read out. Secondly, whether if we saw one positive trial and one negative trial, I think, again, we'd be looking at the totality of data, but there is precedence for that with the other product in the field. So we don't think that, by itself, that would be a showstopper. We remain very encouraged and we are very pleased with the breakthrough designation that Litifilimab got for CLE earlier this year. And we also just presented data from a second Phase II that was positive in CLE. So we continue to be optimistic.

Chris, you mentioned you're still looking at BD opportunities even post Apellis. Maybe just help us with how maybe you rank external innovation versus investments and internal R&D and SG&A, obviously, post the Apellis you need to make investments to get the growth profile going?

Yes. So I think — thanks, Geoff. We feel, as we have said in the past, I think we're feeling very good about our late-stage pipeline — lupus, I think, could be quite a significant franchise for us because in addition to Litifilimab, we also have a partnership with UCB on dapirolizumab, and we will be taking the marketing lead in the U.S. and Japan on that product. And of course, we have some other assets in early-stage development coming along for lupus. The whole nephrology franchise, I think, is going to be quite significant for us as well. And then obviously, we have Apellis. So as we look at BD, I would say, really that most of what we're going to be focusing on is early-stage development and research because that part of the pipeline is quite thin. We have strengthened that with a few collaborations, particularly in immunology with Banca and Dara for instance, last year and the partnership with Citi and there's some other ones in there. So we're looking at really building the next generation of growth. I think if we execute well and we can bring everything and the pipeline does come through, this should be a company that can grow well into the 2030s. And what we need to really be thinking about is what comes after that. So that's where, as I say, the early-stage research stage pre-IND and perhaps Phase I is where the focus is going to be. I think on M&A, we would probably be more opportunistic. I don't think there's any particular need at that point to do that. But I guess we'll keep an eye on it, but we're not going to be doing the aggressive search. So over the last two, three years, I mean, we have had a very systematic search and felt that we wanted to do M&A. I would say with the Apellis transaction and with the pipeline, we don't see the same need to be as proactive on that front.

Going back to BIIB080. You guys had downsized the study from 700 patients. I think you ultimately had targeted or ultimately about 400 patients and why is the cut expenses to get a signal. Can you just remind us, given the context of wanting to be thoughtful about expenses. What type of trend it would make sense for you to push forward, but on the other hand, when you come out with the data, if you don't think there's a really strong trend that you'd be pretty clear about that and would therefore signal to Street that we don't plan to invest there. Maybe just add some color to that, Chris, or Priya, help us understand in terms of the disclosure and how we should be thoughtful about it.

Thanks, Mike. I think just stepping back, yes, we had designed the original CELIA trial with a larger N and I think it was our Phase Ib trial readout that gave us the confidence to redo the power for that study and redesign that trial. And so we feel quite confident that the trial is adequately set up to give us an answer on really testing this very important hypothesis because we already saw the tau reduction in Phase Ib and now we're looking for the transition of tau reduction to clinical efficacy. Just as a reminder, the primary endpoint of the trial is CDR-Sum of Boxes, which, as you know, is a validated endpoint, but we are looking at a few different doses and two treatment paradigms, quarterly as well as six monthly. So we'll be, again, looking at the totality of that to see if we can isolate a signal of clinical efficacy. And I think we'll be very disciplined in how we look at that. The way we've really changed that over several years now is that we think about our go/no-go criteria well ahead of data readouts and this data readout is expected midyear. So you can expect that we'll be looking at that data very carefully, but with really being very disciplined about what the next step is, because that is what this proof of concept is designed for, if and how we get to Phase III.

I think one of the interesting here is that, again, there's just no precedent here, right? And designing the study, I think, it would be fair to say, we basically looked at what we did with amyloid trials, right? We've got the 18-month follow-up. We're looking at a similar population because that's the only thing we know. So we're going to be discovering an awful lot in this study. Certainly, you want to see the right reduction in tau and tau PET results will be important. And then obviously, can you see some movement on cognition. That would be important to be able to advance. Does that have to be statistically significant? Does that have to be a certain percentage. I think that's where the totality of information is going to be while we feel relatively confident in being able to reduce the tau, nobody knows how long you have to reduce the tau for to get a benefit on cognition. And when you think about the progression of plaque, that is a longer onset and tau is a shorter onset. So we don't really know exactly who the right patient population is going to be. That might be the same as amyloid might be different. And that's why we've said from the outset, this is a pioneering study. And we and the whole medical academic community are going to learn from that. The bar doesn't necessarily have to be that high. But I think we do have to see some signs that give us — obviously, hope that this would have a clinical benefit.

On LEQEMBI, could you update us on the adoption and use of blood-based biomarkers and whether you're seeing patients who completed to some less switch to LEQEMBI maintenance?

Maybe Alicia, you would like to take that one?

Sure. Blood-based biomarkers have been growing almost at the same clip as what we've been seeing in the past over 2023, which we know they've had really rapid adoption. However, they haven't typically been used for confirmation solely. But what we are seeing, there is a PCP pilot that is going on right now, as you know, with Biogen and Eisai, and we do have early indicators that from that pilot, we're seeing a higher usage now of blood-based biomarkers in the PCPs than what we do in places that do not have that pilot running. So we're showing that once we educate, they are doing it more and more. Also more importantly, recently, CMS did add that blood-based biomarkers can be used as a confirmation when you go into their database, so when you go and use the drug, you can actually get it reimbursed. I know last year, that was a big question that physicians had and now that has also been put into place. So I believe, moving forward, we are going to see that blood-based biomarkers will be used more and more for confirmation than they are today. The adoption will be a little bit slow, but awareness is extremely high. So I do think the more that they use it, test and try it, the more they'll be used for confirmation. When you move towards something — the question that you asked about alternative therapy in this first quarter of the year is when you'll expect to see the tranche of patients that started on alternative therapy that are now hitting their 18-month mark. And so quarter one is when you will see the patients now typically stopping the product and for us to start getting the feedback. I can say that physicians are asking what do we do with some patients. And if you look at market research, patients in general, who are in either of the products want to stay on product, there is a fear of coming off and having a decline in their cognition. And we do have several accounts that are looking at how do they switch them to LEQEMBI, as you know, we cannot provide detailed data on that because we don't have data, but we do have physicians that are looking at, can we switch them to maintenance or to subcutaneous maintenance of LEQEMBI.

So high-level question on SYFOVRE. If you can talk to it. I know the transaction hasn't closed. But can you comment at a high level on evolving competitive dynamics, particularly with other agents that are in development that are focused in terms of their primary outcome measures on visual acuity as opposed to lesion burden. So help us just understand how are you thinking about where SYFOVRE is going to fit in this evolving landscape. And ultimately, what kind of data you can point to regarding the product regarding its impact on visual acuity.

Thanks, David. So just stepping back, I mean I think SYFOVRE is indicated for geographic atrophy. This is a very highly prevalent irreversible and progressive disease that leads to blindness. I think the median time point is about six, six and a half years. And the gold standard for assessing efficacy has been lesion growth. And I think that is where SYFOVRE has very compelling data, 42% statistically significant reduction in lesion growth at the time of launch. But subsequently, Apellis has also presented five-year long-term data that shows that you can actually slow down progression by about 1.5 years. That's obviously really meaningful in that time frame of six years. I totally agree that there is competitive dynamics here. I think with either way, the other product that's on the market targets C5, which is upstream of C3, which is the target for SYFOVRE. And we haven't really seen that long-term data as of now from those competitors. But moving into what's on the horizon from a competitive landscape, I think we are seeing more targeting of C5 again. That's one. The other is that with Annexon, we haven't seen that the Phase II data were very persuasive. And actually, it did not impact geographic atrophy lesion growth, which we believe is the standard, gold standard. And Chris mentioned the lesion growth is really important; eventually the best corrected visual acuity would be impacted. But at the outset, that's not really the goal because the eye adjusts to peripheral vision, and that's an important aspect to keep in mind. And when we saw the data from Annexon, this was obviously a very important aspect of our diligence; we saw that actually the BCVA for placebo really went down, and therefore the drug arm looked good, but I think it remains to be seen. With regards to Regeneron, I know that's competition as well, also targeting C5 and it's systemic, and it's a combination. So we believe Syfovre because it's targeted to the eye, it really enables that tissue delivery, which we believe is really important. And Regeneron, the proof of concept still has to come. So we'll wait for that. But we do know that Soliris actually with a very similar mechanism of action failed in Phase II in GA. So I think a lot to watch out for, but we feel really that the IFB data are compelling, and it's going to be a very huge effort for us from an educational, medical, scientific leadership perspective to make the case on why it's important to treat now.

Yes. And I think from a commercial point of view, the fact that SYFOVRE has five-year data creates sort of a data moat here. This is a progressive, slowly progressive disease. And people want to have confidence in the safety and how this also develops over time. So I think it's going to take quite a long time for any competitor actually to generate the same level of data that is going to be necessary for the confidence of physicians and patients.

Great. And congrats on a great quarter. A couple of other just quick hits on SYFOVRE if I may. As it relates to just thinking about spending on that franchise over the next few years, how are you at least qualitatively right now thinking about synergies and leveraging existing capabilities with also the reality that GA may still be a pretty promotionally sensitive market that could require things like DTC. And then maybe just any quick thoughts on the prefilled syringe, your level of optimism there and how meaningful that could be?

So Alicia, you have a lot of work in this space.

Yes, I'll take that question. Thank you. First, I can say that we've met several of the leaders over at Apellis, and I want to say that I'm very impressed with that team and with the leadership that they actually have. Many of those individuals have had the ophthalmology background for quite a long time and know the space very well. So I will say they've done a very good job and a tremendous job, especially with the vasculitis cases that came up early on in handling that, and I think they're doing a very nice job today. When we look at this market and see the opportunities that it has, it is a very large market. It's 1.5 million patients, as you know, only 20% are treated. And there is a really significant unmet need for this patient population. And this launch has sustained growth in injections and in patient growth. And so we believe there is a very large number of patients who are untreated. There's around 500,000 that currently sit in these targeted physician offices that this team currently calls on for GA. And in our experience, when you have a product that slows progression, activating the patients and creating urgency with these HCPs is critically important. And therefore, we know moving forward, we will need thoughtful education, very strong messaging and an explanation as to why there is a strong value to slowing this progression. With that being said and knowing that we obviously do not — we have not closed the deal yet. We know that activating these patients will be critical in this space because when you go in and ask for something, you typically get it. So we do know we will be spending money on DTC and TV ads, as you know, they did run TV ads for two quarters, and they did stop those TV ads. I think that would be something that we'd be looking at once we close the deal because educating these patients will be critically important. We'll also be looking at the messaging for how they're able to handle this in the office. We have no idea up into the space, how much time have they had to spend on vasculitis versus actually being able to compete hand-in-hand in these offices. And thirdly, I think that they are going to benefit greatly from our patient services and also from this machine that we've had the luxury of building over the last seven years. If you really take a step back and look at Biogen, especially in North America, we've launched seven products over the last seven years in completely different spaces, which means we've created this dynamic engine that has been able to support the launches across all of the therapeutic areas that we now have. Therefore, we believe, going to your question, we will find synergies and a lot of the headquarters capabilities that we will bring to them that maybe they have not been able to invest in. We're also going to look at where they currently spend money that maybe we could reallocate to some of these other areas that we believe will drive the growth. And we're going to be able to do a great analytics in understanding which tactics they're using now they think are working and which ones we might be able to tweak moving forward. I also have an understanding that they might have a wish list of things they'd like to do, maybe they haven't done so far for the launch. And so we are going to be looking at all of that with them, and believe with Apellis and with Biogen, both of them together will be much stronger than either one of them alone. And so I know my teams are very excited about welcoming them into North America. And we're looking at giving specialist support for SYFOVRE a lot of support, so they feel like they have everything they need to succeed in this space.

Congrats on all the progress. So would love to understand high-dose SPINRAZA helps with switching and persistence as a new offering, do you think it can stabilize the franchise or even grow at this point? Would love to understand how you're thinking about it.

You want to take that from North America, Alicia?

Is the question specifically about SPINRAZA or SPINRAZA high dose?

High dose?

High dose. Okay. Well, first of all, I'll say that I'm sitting in the same boardroom I was sitting in when we had a patient advocacy group, and I pitched to a couple of executive committee members that we had feedback from patients that they wanted more. And you fast forward to today, we all of a sudden have SPINRAZA HD. So first and foremost, I will say this is one area of the business which I have never seen in my career where this patient community is smart, they are savvy. They know exactly what comes out, when it's coming out, and they will make those requests prior to any approval in the market. So when you look at what has happened, SPINRAZA HD has been out less than a month. I will tell you that 20% of my patient base already have start forms in to go and get SPINRAZA the high dose. We also have patients that are switching from competitors and patients that are adding on to Zolgensma. So for the U.S. organization specifically, I do believe that high dose, which we've had a pretty stable business so far with SPINRAZA, and my team has done an excellent job with SPINRAZA 12 mg, but we do believe high dose now has a new opportunity for us, and we are seeing great interest in high dose from not just patients but also physicians. And so we're off to a great start. Hundreds of start forms have been submitted and I think that this is going to be very positive as we transition from SPINRAZA high dose and hopefully one day Salanersen.

Maybe, Chris, I can cover ex-U.S. similarly, we had the approval ex-U.S. in Europe, and we're seeing similar traction, particularly in Germany with roughly 20% of the patients converting over to high dose. So off to a really strong launch in Europe as well.

I think when you think about high dose, you think about also the being able to potentially replace the intrathecal injection coming along. And then obviously, Salanersen, I think, Priya, can say we've had our first patient dosed in the Phase III study here. I think this is a franchise that is going to be durable and can grow over time as we introduce these things that make it easier. Now I talk to physicians around the world when I go visit our affiliates. And every time they talk about someone who has switched off SPINRAZA, there's always a tone of regret in their voice. It generally is because of intrathecal fatigue, but they have the regret because they know that in their view that this is the most efficacious drug. And I think the HD now gives them even more reason to defend the efficacy — and I think, again, with the device we hope can eliminate some of the intrathecal fatigue. And certainly, by the time we get Salanersen, that's expected to be a once-yearly intrathecal and that should also help with the administration. But these are — it's amazing to hear the emotion of physicians. These are children who are now going to school who would have died years before. And this is just one of those amazing medicines that Biogen has come up with that has had such an impact on health care for, particularly in the pediatric population.

Congrats on all the progress. I'd love to drill down a little more on the strength we saw with SKYCLARYS. Can you walk me through some of the drivers of this? I know it's been a lumpy product. But is this traction something we should really start to think through later in the year? And kind of what are some of the drivers there?

Don't you start with the U.S., and then we can talk about ex-U.S.?

Yes. So for SKYCLARYS, which you saw for the quarter is with the $72 million year-over-year, it was a 4% growth quarter-over-quarter, it was down. And it was down because the inventory was built at the end of Q4 last year. And then fast forward to Q1, if you look at the amount of buying weeks, Q1 has two fewer buying weeks than the prior quarter. If you look at patient demand, our patient demand was right on par — it's just we had a little bit of lumpiness with the inventory. Now the second thing, though, just to remind everyone is where the U.S. is at launch, is we are now at the launch phase where we are going out, we are using our patient-finding, our next-best-action in the field where our reps every week receive a list of all the different offices they can go visit because we believe the patient is there, and then they go on the hunt. With that being said, now the majority of our patients are coming from doctors who will only ever write one prescription ever for Friedreich's ataxia. These patients tend to be slower progressors and they're much older than what we had predicted when we first launched the product. And so it will take more time as we find them. But the good news is that we are finding them and they are going on product, but it does take time from finding the patient to when they finally put in their script.

In ex-U.S., actually, our revenue in the quarter exceeded the U.S. for the first time from SKYCLARYS as we continue to execute on the launch there in Europe and starting in Latin America. So we do see from a demand perspective, demand increasing ex-U.S. and expect that to continue as we continue the launches. And as I mentioned earlier, it's already available in 35 countries.

In ex-U.S., we have a little different strategy. So as Alicia said, it's really finding the patients. So as we found the patients, we have put them on drug and they're on early access programs while we negotiate reimbursement. So as we get reimbursement, you'll start to see the revenue suddenly flow through. But it might be lumpy because we can switch potentially several hundred patients all at once from being a zero-revenue patient to a full-revenue patient. We have not only had more patients outside the U.S. on drug in early access, they haven't been fully reimbursed. And that's progressive. And we're now seeing really the rollout and potential reimbursement in Latin America, for example.

Another on BIIB080, what's the potential in other tauopathies. And as a follow-up, what will be the most important biomarker from the upcoming Phase II results in terms of informing next steps beyond Alzheimer's?

Yes. Thank you. This is an area that we are discussing quite deeply. We know the high unmet need in primary tauopathies. And what we've seen in terms of our reduction with BIIB080 at least in our Phase Ib trial was very encouraging. I think we would be looking for tau reduction and we would be looking for other details, I mean, regions of the brain and such, and that would inform our strategy on whether we would continue to think about doing more work in primary tauopathies. But yes, it remains high on our list of evaluations and potential possibilities.

Just one on FELZ for me and AMR. Obviously, you called out the acquisition of the China rights for $100 million and then some pretty significant back-end loaded milestones. So just thinking through what this means for the broader commercial opportunity maybe both, not just in China but also on a global basis and how you're thinking about that relative to consensus.

Yes. Again, I think as you look at kidney disease, a lot of this — there have not been treatments for it. And there's a whole alphabet soup of these things, right? You've got MPGN, you've got AMR, you've got PMN. You've got C3G and I think it takes — it's hard to actually even to come up with sometimes the epidemiology. I can tell you on the MPGN for Empaveli, it's actually not very clear exactly what the actual underlying epidemiology is. So it's hard for, I think, investors to really assess some of these. What we do know, for instance on AMR is we just take that there are about probably 11,000 patients. And if you actually look at the price of IgAN, it certainly if you look at it with the latest Otsuka price in IgAN of about $350,000 a year, you're looking at a total addressable market north of $2 billion, somewhere between $2 billion and $3 billion, in fact. And there hasn't been any treatment there in the past. And certainly, the Phase II data, although small numbers, showed a remarkable 80% resolution of AMR. And then you've got MVI, which is sort of a cousin of AMR, that adds another five to six thousand patients, and we've just initiated a trial in MVI. IgAN is obviously going to be a significant market, particularly in Asia. And I think there's two things where we see competitiveness. When you start looking at any autoimmune disease, you really want to think about where are you in the whole immune cascade. In most cases, if you're treating an autoimmune disease, you're trying to suppress the immune system. You don't really want to do that any more than you have to. And so having something that is close to the actual disease cause, I think, is going to be relevant. And that's where we think CD38 is a huge advantage of really acting on the plasma cells and the NK cells. But the other is really the durability of treatment. In IgAN, we showed in a Phase II that after nine infusions we still had durability of treatment after 18 months. And that says that maybe we're doing something here that looks more disease-modifying than other agents. Priya, you should probably weigh in here since you're much more expert than I am on this.

I think you covered it well, Chris. We're really excited about the first readout of felzartamab. We expect this in 2027. And really, it's — stepping back — it's targeting the CD38-positive plasma cells, which we believe are a key source of the pathogenic autoantibodies, and the readout is really a biopsy readout, which is also very objective. So we're excited about this.

Great. I think we've got time for one last question. Maybe that's the last one, please.

Congrats on the quarter. Can you talk about the real-world treatment persistence of LEQEMBI that was presented at ADPD with regards to — how do you expect the subcutaneous version to further impact treatment persistence?

Thanks, Jay. So overall, there's been a question lingering out there whether after reduction and clearance of plaques, you continue to keep patients on an anti-amyloid therapy, specifically one like LEQEMBI, which has a dual target of the soluble toxic species as well as plaque reduction. We've shown extensive data in prior meetings on the benefits of keeping patients on therapy. This again is a progressive disease. Once neurons die, you cannot recover them. And we've shown that fluid biomarkers actually come back within less than six months, and then although the plaque comes back much slower. So that's one piece. I think the real-world evidence data is compelling because it shows that patients and neurologists actually want to continue to stay on therapy. That, I think, is the powerful reflection of that data. And this continues to be really, really important for us. Now we already have subcutaneous maintenance, which again makes it simpler and offers patients optionality on staying on therapy. But with subcutaneous initiation where we'll get an outcome from the FDA next month, we continue to remain very optimistic about how this could inflect in terms of the patient journey. And then finally, I'll just add a point about our presymptomatic trial of HEAD345, which is still to read out in 2028. And we'll see about that readout. We think it's going to be an important landmark trial in the field. But what becomes important with subcutaneous initiation getting accepted is that there could be an interchangeability, which could be very relevant in the presymptomatic population. So again, we believe that this is going to be a very important inflection point.

Thanks, Priya. Thanks, everybody, for joining the call today. We've got more questions; please reach out to me or investor relations. Thank you.