Biogen Inc at Stifel Virtual CNS Forum Summary

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

Question: Paul Matteis - Stifel - Analyst : Yes. Okay. Great. Well, we're going to try to take time and go through each of the assets you mentioned and a couple of the key questions. But maybe one more forward-looking question for you just in terms of the whole where is Biogen going? And I guess it wouldn't be a Biogen panel without the token business development. We super cool like anti-LINGO-2 program. And it feels like Chris now talks a lot more about rare disease and immunology as key areas. So just as it relates to CNS specifically, is this an area you think you'll continue to build out and take on risk in? Or is it an area where you feel like your portfolio is full and you're trying to continue to shift elsewhere?

Question: Paul Matteis - Stifel - Analyst : Yes. Okay. Fair enough. As it relates to taking on risk, what gave you and your team conviction about executing the Stoke deal before Phase 3?

Question: Paul Matteis - Stifel - Analyst : Yes. So I mean, this is a tremendously interesting program. And just as it relates to epilepsy more broadly being kind of going through like it's not a shift because I don't think it's ever going to be broadly like this, but like a subtle shift towards precision medicine. We felt like one of the key questions with this program, and obviously, given the mode of administration, this would be a big commercial swing factor to the upside, right, if this is successful, is the cognition piece. And I was curious how you think about this question and whether you think this question is relevant. But if you were developing a drug for cognitive impairment in schizophrenia, right, you'd be pursuing a population that is not acutely psychotic, right, because the FDA wants you to decouple cognitive benefit and benefit on psychosis. As it relates to the Stoke asset, do you look at that data and think this impact on cognition is independent of seizure reduction? And I guess as you think about getting like a label for this and a claim for this and marketing this, like does that matter? Like how should we think about that?

Question: Paul Matteis - Stifel - Analyst : Yes. Okay. Great. All right. Let's maybe just do hits around the whole pipeline. So on lecanemab subcu, can you remind us of just the general time lines there? And as it relates to subcu initiation, how has the program evolved over time as it relates to doing more dose work? And what would you say the target product profile is, specifically as it relates to ARIA and whether you can get to a lower rate of ARIA?

Question: Paul Matteis - Stifel - Analyst : Yes. Okay. That makes sense, Priya. Chris, I've always appreciated his candor about this launch because I think he's not -- he hasn't tried to oversimplify it, right? I mean I think he's been pretty open that this has just been such a complicated launch and like there's so many factors that play in. And I guess now where we are with lecanemab, how would you rank order the impediments to uptake? I would assume -- you tell me if I'm wrong, but I would assume subcu maintenance might have an incremental impact on uptake just because you have to be on the drug for so long. For subcu initiation, like how much of a game changer is that? Or is it still more about everything else, seeing a neurologist, the MRIs, et cetera?

Question: Paul Matteis - Stifel - Analyst : How would you think about the probability of success for a credible blood-based biomarker coming to the market in the next one to two years?

Question: Paul Matteis - Stifel - Analyst : What should we be looking at -- do you want to just help people what should we be looking out for?

Question: Paul Matteis - Stifel - Analyst : Yes. Yes. Okay. Very interesting. Let's talk about the tau program. And I think the natural question -- and you guys have some data to address this, but the natural question for me for any of these intrathecally administered products, be it antisense oligonucleotides, RNA, gene therapy is, are you getting enough target engagement across the key areas of the brain? And I think it's like complicated, but I think as we've tried to bridge from the early successes in spinal muscular atrophy to other diseases, right, like the success rate has been very mixed. And again, it's nuanced, but one of those -- if -- one of the reasons, I think, is biodistribution. And so to that point, can you just review for everybody the target engagement data you've generated and your level of conviction that you are reducing tau levels in the brain areas that matter in Alzheimer's?

Question: Paul Matteis - Stifel - Analyst : Can I clarify something with you? Have any of the antibodies that have failed shown an effect on tau PET to your knowledge?

Question: Paul Matteis - Stifel - Analyst : Not to mine either. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 18, 2025 / 2:15PM, BIIB.OQ - Biogen Inc at Stifel Virtual CNS Forum

Question: Paul Matteis - Stifel - Analyst : Yes.

Question: Paul Matteis - Stifel - Analyst : Yes. No, I'm very excited about that program, too. Can you -- maybe some of the other just biological questions that I think come up with tau. I mean one is the right time to intervene or the right window for intervention. So maybe you can comment a little bit on that when we think it plays a role in the disease? And then the second is just tau, if you just read about it on a base biology level, right? I mean it's evolutionarily conserved. It's talked about an important cytoskeletal protein. Like how confident can we be that knocking it down is not going to have some sort of safety down?

Question: Paul Matteis - Stifel - Analyst : Yes.

Question: Paul Matteis - Stifel - Analyst : Yes. Yes. Okay. Great. What are you power for from an effect size perspective? And do you think the effect size for something like this, given the IT administration has to be bigger? How do you think about the clinical hurdle?

Question: Paul Matteis - Stifel - Analyst : Yes. Yes. Okay. Last question here, and it's really just on the oligo brain space in general. Do you have a view on the brain shuttle approaches? I think we've seen -- we've seen these approaches in the brain validated with antibodies, proteins, enzymes. And then in the muscle space, right, also with transferrin, we've seen that oligos are a viable target, you can deliver to the right part of the cell. And I know there's interest with this tau target specifically with brain shuttle approaches, which, again, super early, higher risk, but could be IV. Is this something that Biogen has on its radar?

Question: Paul Matteis - Stifel - Analyst : Yes. Okay. Okay. All right. Let's talk about lupus a bit. So -- and then we can maybe talk about felza and IgAN and the transplant space as well. But just as it relates to lupus, it's interesting, right, because I feel like Biogen's stock doesn't get much credit for dapi or litifilimab. And I think the things that hold investors back, one is that in the dapi Phase III, right, the study was positive, but the p-value was close, right? So there's a question on how much margin is there for the next study? Can we be confident in the replicability of it? And then just the second question more broadly is that it's weird. On the one hand, lupus feels like it's this big unmet need. On the other hand, it feels like it's a competitive space, right? I mean there's a lot of stuff in development. And I think it's hard for people to kind of figure out where different assets fit in. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 18, 2025 / 2:15PM, BIIB.OQ - Biogen Inc at Stifel Virtual CNS Forum So I realize that there's multiple questions there, but it would be great to kind of get your snapshot on both the clinical risk side and then just the positioning side as well for your two assets.

Question: Paul Matteis - Stifel - Analyst : Yes. Okay. Great. We only have a couple of minutes left. So I just want to try to cover felza and anything else to close. But just as it relates to the H bio deal, there's data in IgAN, there's work going on in AMR and PMN. I think, again, like we think about what holds investors back from ascribing value of these assets. I think people have a hard time understanding like in what area is this the best drug, right? Or like which indication is the flagship indication? How would you answer the question about where you're most excited for this? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 18, 2025 / 2:15PM, BIIB.OQ - Biogen Inc at Stifel Virtual CNS Forum

Question: Paul Matteis - Stifel - Analyst : Is that the counterpoint to when investors, I think, make a table of these drugs and they just compare a percent change in proteinuria, like this doesn't rank at the top of the list. So is it more about the dosing holiday that got you comfortable with that or got you excited about this in (inaudible)

Question: Paul Matteis - Stifel - Analyst : Yes. Yes. Okay. I am just looking at a couple of questions that came in because we only have a minute left. One asking for -- we'll see what we get Priya, but a comment on anything Sage, right? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 18, 2025 / 2:15PM, BIIB.OQ - Biogen Inc at Stifel Virtual CNS Forum And then just any updates on development work with SPINRAZA and then we can close.

Question: Paul Matteis - Stifel - Analyst : Great. All right. Well, we're 1 minute over. I want to be respectful of your time.

Question: Paul Matteis - Stifel - Analyst : Thank you, Priya. This was an awesome discussion. I think we covered a lot of interesting stuff. So I appreciate you joining us.