Hello, and thank you for joining us. Welcome to Acumen Pharmaceuticals Q2 2024 conference call and webcast. All participants are currently in listen-only mode. After the presentation, we will have a question-and-answer session. I will now hand the call over to Alex Braun, Head of Investor Relations. Please continue.

Thank you, operator. Good morning and welcome to the Acumen conference call to discuss our business update and financial results for the quarter ended June 30, 2024. With me today are Dan O’Connell, our CEO; and Matt Zuga, our CFO and Chief Business Officer. Dan and Matt have some prepared remarks, and then we'll open the call for questions. Joining for the Q&A session, we also have Dr. Jim Doherty, our President and Chief Development Officer, and Dr. Eric Siemers, our Chief Medical Officer. Before we begin, we encourage listeners to go to the Investor's section of the Acumen website to find our press release issued this morning that we'll discuss today. Please note that during today's conference call, we may make forward-looking statements within the meaning of the federal securities laws, including statements concerning our financial outlook and expected business plans. These statements are subject to risks and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. Please see slide two of our corporate presentation, our press release issued this morning and our most recent annual and quarterly reports filed with the SEC for important risk factors that could cause our actual results to differ materially from those expressed or implied in the forward-looking statements. We undertake no obligation to update or revise the information provided on this call or in the accompanying presentation as a result of new information or future results or developments. And with that, I'll turn the call over to Dan.

Thanks, Alex. Good morning, everyone, and thanks for joining us today. We've made significant progress in the first half of 2024 as we continue to execute our clinical plans for sabirnetug, our next-generation amyloid beta oligomers targeted antibody for the treatment of early Alzheimer's disease. ALTITUDE-AD, our Phase 2 study designed to evaluate the clinical efficacy and safety of sabirnetug in patients with MCI or mild dementia due to AD, is actively enrolling. ALTITUDE-AD is a randomized double-blind placebo-controlled pre-arm study with approximately 180 participants per treatment arm for a total of 540 participants. ALTITUDE currently has more than 50 sites active across North America, the UK, and the EU, with the first subject dose in May 2024. At present, enrollment in ALTITUDE is progressing faster than our original projections, which is highly encouraging. We attribute this to sabirnetug’s distinct profile based on its mechanism of action and positive feedback and interest from investigators supported by our strong Phase 1 data. Additionally, our team has built highly productive working relationships with quality trial sites in all three regions. These combined factors have translated into an encouraging enrollment rate and underpin the growing interest in novel treatment options for early AD and the differentiated treatment potential of sabirnetug. In July, we also announced we had dosed our first subject in a Phase 1 study of subcutaneous sabirnetug. The study will compare the pharmacokinetics between intravenous and subcutaneous administrations of sabirnetug in healthy volunteers. We view this work stream as an important extension of sabirnetug's product profile, which aims to offer flexibility and convenience in dosing for patients and caregivers. We anticipate the top line results from this study will be available in the first quarter of 2025. Once we have the PK bioavailability results in hand, we will be best positioned to discuss next steps and clinical plans for subcutaneous sabirnetug. Turning now to continued learnings from our clinical experience with sabirnetug. The Acumen team recently presented further data analysis from the INTERCEPT-AD trial at the Alzheimer's Association International Conference or AAIC. Our team presented posters at this major Alzheimer's medical conference detailing patient interviews, biomarker data supportive of sabirnetug's mechanism of action, and Acumen's ultra-sensitive method of measuring small amounts of sabirnetug in cerebrospinal fluid. The takeaways from our patient interviews underscore the importance of incorporating the patient voice into trial design and humanizing the unmet need in Alzheimer's disease. As expected, nearly all patients reported difficulty with memory and cognition, difficulty with getting lost, difficulty with communication, and changes in mood were also commonly reported. Almost 90% of patients would like a treatment to slow the progression of disease or keep it from getting worse, as well as maintain the ability to recognize loved ones. We also received strong interest in the synaptic biomarker changes observed in our Phase 1 study; both pre and post-synaptic cerebrospinal fluid proteins, VAMP2 and neurogranin showed significant reduction towards normalization, which is consistent with sabirnetug's ability to inhibit amyloid beta oligomers' synaptic binding. These posters can be found on the Investor section of our website, if you haven't already had a chance to review them. As usual, there was a great deal of interesting information shared at AAIC, including a number of topics relevant to our sabirnetug program. These topics included the continued development of fluid biomarkers, like pTau217, as diagnostics for tracking the progression of Alzheimer's, further data on the important role that soluble amyloid beta species play in the pathophysiology of AD, and extended safety and efficacy data on chronic dosing with anti-amyloid monoclonal antibody therapies. We believe the increased acceptance of the toxicity and persistence of soluble amyloid beta species, such as oligomers, will help move the field towards next-generation antibodies such as sabirnetug, and the confidence of fluid biomarker breakthroughs will support expanded future access to novel treatments in AD. Finally, we are planning to host a virtual R&D day on October 2. We intend for this event to provide a deep dive into the scientific rationale of supporting sabirnetug's mechanism of action, our Phase 1 clinical results, and Phase 2 clinical plans for sabirnetug. We will communicate the registration details and agenda closer to the event. We remain committed to delivering on our strategic priority to efficiently and thoughtfully advance the current development of sabirnetug and are encouraged by the direction that the Alzheimer's field is headed with new data and an updated understanding of the disease that is in line with our science. I look forward to updating you as we work towards Phase 2 data that we believe will provide a significant value inflection for the program and demonstrate sabirnetug's true potential as a next-gen treatment with a highly compelling benefits-risk profile. And with that, I'll turn the call over to Matt for the financials. Thank you.

Thanks, Dan. As a reminder, our second quarter 2024 financial results are available in the press release we issued this morning, and in our 10-Q, we will file later today. As of June 30, we had approximately $281 million in cash and marketable securities on our balance sheet and continue to expect the cash runway to last into the first half of 2027. R&D expenses were $19.5 million in the second quarter. The increase over the prior year was primarily due to the increased spending to support the ALTITUDE-AD trial. G&A expenses were $4.8 million in the quarter, with the increase over the prior year primarily the result of increased headcount. This led to a loss from operations of $24.4 million in the quarter. I'm very pleased with our clinical execution thus far in 2024. We are well resourced to support our Phase 2 study and to develop a subcutaneous formulation of sabirnetug, and are committed to delivering on the opportunity ahead of us for the benefit of patients, caregivers, and shareholders. And with that, we can open the call for Q&A.

Thank you. Our first question comes from Tom Shrader with BTIG. Your line is open.

Good morning. Thanks for taking the question and the updates. I have a question on the Phase 2 trial and what patients you are getting. What is enrollment like in the U.S. with two approved products? Is it tricky or are patients highly compelled by the potential for less ARIA? And I would expect enrollment in Europe, as people are very enthusiastic, but are you going to limit or are you going to require some number of U.S. patients? Thank you.

Hi Tom. Yeah, thanks. That’s a great question. As I mentioned earlier in the prepared remarks, we are encouraged by the enrollment rate and to date it has exceeded our expectations from our original forecast. I think this is a consequence of the unmet need in this population, as well as the Phase 1 data that really underpin the differentiation of sabirnetug. Lastly, the study design itself, the feedback from sites and investigators has been very favorable in that the study incorporates two active doses versus placebo and then an open label extension. So, in terms of choice and participation, we're seeing a lot of demand to participate in the ALTITUDE-AD study. We do anticipate a split between North America and Europe. I haven't preset those numbers, but I think we'll have patients covering each of the territories or regions that I mentioned earlier.

Okay. All right. Thank you.

Maybe I’ll just add a little bit to that. Yeah, the rate at which we're seeing patients really exceeds our projections and expectations, which is great. You might ask yourself why that might be. As Dan mentioned, it's probably multifactorial, but I think partly it's the strength of our Phase 1 data that was done in patients. We've seen a lot of biomarker changes that are really encouraging for the drug. Secondly, what we've heard from the sites is that they do like the protocol design. It's a Phase 2 study, but really it's like a small Phase 3 study, with an open label extension in the sites like that. We started the study in the U.S. and that's where currently we have most of our patients, but now we're adding sites. We've already added sites in Canada, the UK, and then Europe. So we'll be enrolling more patients in those other geographies.

Okay. Great. Thank you.

Thank you. Please stand by for our next question. Our next question comes from the line of Jason Zemansky with Bank of America. Your line is open.

Hi. Good morning. This is Cameron Bozdog on for Jason. Congrats on the quarter and thanks for taking our question. So in thinking about the anti-Abeta commercial landscape, what do you think have been the major challenges or gating factors? Is it educating physicians, engaging with patients, or has it been an issue of infrastructure, payer access, reimbursement? And then appreciating it's early, but do you see opportunities for sabirnetug to potentially differentiate itself, or is it more that the broader market needs to finish undergoing maturation itself? Thank you.

Thanks, Cameron. I think you've listed out the multifactorial sort of issues that are inhibiting or at least metering out the ramp and the growth and expansion of these treatments, these first couple of approved products. We think that it's interesting now with Lilly coming into the marketplace. The infrastructure will continue to be built out. That awareness around the possibility of seeking treatment will continue to draw more awareness in patients into this new treatment paradigm. There are also, I think one of the points we made from the AAIC meeting is that the anticipation of fluid biomarkers, blood-based diagnostics is likely to impact the growth and expansion of this field. So it is multifactorial. I think there's been good progress made and there'll continue to be the infrastructure rolled out. In terms of sabirnetug and its differentiation, we absolutely have high conviction that its mechanism is differentiated. And yet, as a consequence of that, it has the promise of differentiating either or both on efficacy and safety. And that's really our single focus, is to offer early AD patients an improved treatment option in terms of benefit to risk profile. So I think that addresses most of your questions. I don’t know, Jim or Eric, if you have any follow-on comments.

Thank you. Please stand by for our next question. Our next question comes from the line of Paul Matias with Stifel. Your line is open.

Hey, this is Mark on for Paul. Thanks for taking our questions. So we were curious, what does the path forward look like for the subcutaneous formulation for sabirnetug? And then, would that be assessed in parallel to the intravenous formulation? If the Phase 1 were successful, and then separately on that. What dose could you pursue? And would that enable robust plaque target engagement, or would that be more of like an oligomer dose? And then, if you could provide any additional details for the ALTITUDE-AD interim analysis, that would be great as well. Thank you.

Sure, I want to direct that one to Jim as our lead on development efforts.

Sure, happy to take it, Dan. Mark, the answer to your question is that the first step really for the subcutaneous development program is to understand the bioavailability of a subcu version. So that's the goal of the first study here in healthy volunteers, is to really align the PK from the subcu administration with the Halozyme formulation with what we're learning from the IV studies from Intercept and ongoing work with ALTITUDE-AD. I think beyond that, we have a number of options on how to proceed. I think from the point of view of dosing, the targeting of the dosing is intended to hit the same range that we're targeting with the IV formulation. And the purpose of that, of course, is based on our target engagement data from Phase 1. We've got high confidence that we are targeting a range that's having an effect dose-dependently on soluble oligomer in the brain, and also, as we've demonstrated from Intercept, some evidence for plaque reduction as well. And I think we see these as both effects of sabirnetug. We're focused around the hypothesis that the reduction of soluble oligomers is going to be beneficial to synaptic function and to overall cognitive function in AD. And I think there's no reason to think that would be different for the subcutaneous formulation. So that's sort of where we stand at this point. Our efforts are to complete the ongoing Phase 1 subcutaneous study by the end of the year. And then we'll based on a data-driven analysis, move forward with next steps.

Thank you.

Thank you. Please stand by for our next question. Our next question comes from the line of Pete Stavropoulos with Cantor Fitzgerald. Your line is open.

Hi, this is Samantha on the line for Pete. Thanks for taking our question. So the ALTITUDE-AD study is enrolling patients with early AD. Considering the outcomes from other Abeta antibodies in the subpopulations that showed greater clinical benefits, such as those with low tau versus high tau, how are you thinking about the patient population you would like to ideally enroll? Are you looking to have patients with a higher proportion? With specific baseline characteristics like sensoloid levels, plaque or tau to perhaps increase the likelihood of seeing efficacy signals? Thanks so much.

Thanks, Samantha. Eric, do you want to take that one?

Yeah, sure. So, yeah, great question. We're targeting actually the same patient population that we used for the Phase 1 study, which is patients with MCI and mild dementia, which is frequently being called early symptomatic Alzheimer’s disease now. As you point out, people who have less tau based on other antibodies may have a better response to those results carefully. What we've done in our trial is that people can enter the trial based on either a PET scan, an amyloid PET scan or CSF. For the PET scans in particular, we are using a visual read, which is what's used in practice right now, but by doing that, you tend to get people with a little bit lower levels of tau, who are relatively a little bit earlier in the disease. And so we feel pretty confident that we've targeted the right population here. So there are obviously people who have amyloid and they have Alzheimer's disease, but they are relatively early in the course of it, both based on symptoms and based on PET scans or CSF.

And maybe just to add to that a little bit, Samantha. I think part of the reason we're investing so much in both imaging and fluid-based biomarkers in the ALTITUDE study, is that the space is still evolving and understanding exactly what the diversity is amongst patient populations. And so I think as Eric's pointing out, we're very intentionally targeting the early Alzheimer's space. But I think as our understanding is, the field grows in this area, Acumen is going to be very well positioned to understand the importance of individual biomarkers and how that's going to relate to the emerging understanding around different patient populations. So we think we're in pretty good shape at this point.

Thanks so much.

Thank you. Please stand by for our next question. Our next question comes from the line of Trung with UBS. Your line is open.

Hi guys. Trung Huynh from UBS. Thanks for taking my questions. Just on the subcutaneous administration, I've got a couple on there. So do you have any details on this? Is it an auto-injector? Can it be done at home or in the hospital? And what's the injection volume that you are using? Just trying to get an idea of the convenience for this product. And then, can you just give us any color on what could be presented in Q1 with this data? In particular, could we see any safety data? Thanks very much.

Thanks for the question. I'll just quickly say that we will have safety data and we'll have bioavailability data. At this point, we're not guiding or disclosing sort of volumes and so forth. I do think that we're trying to establish the bio-equivalence of subcutaneous versus IV dosing in that therapeutic range that we're using in ALTITUDE-AD, and I think we will have looked for a variety of different delivery formats. We have a fairly clear view as to what we want to deliver on in terms of dosing frequency and volumes, but at this point, I'm not prepared to comment. We're fortunate to be partnered up with Halozyme on this program. And it brought to bear a good bit of information and content and been good partners to help us assess how to advance the subcutaneous formulation of sabirnetug.

Yeah, and maybe just to expand on that a little bit, I just want to remind you that this study is in healthy volunteers. It's not in patients. So ARIA really shouldn't be an issue in terms of safety. So the safety is more just injection site reactions and that sort of thing, but we anticipate that that should be quite good.

And just following up, you mentioned a partnership with Halozyme there. Should we expect what the financials are there? Should we expect a pay our way here? I know it's a bit down the line.

Yeah, so it's down the line. I mean, the terms are not disclosed publicly. I think it is a matter of public record though. This is a non-exclusive arrangement with Halozyme.

Thank you. Our next question comes from Ananda Ghosh with HC Wainwright. Your line is open.

Yeah, hi. Congrats on the quarter. I have two questions. The first one is, can pTau217 predict low and high Tau patient population? Now, are there data from the prior clinical trials? And the second question is with the lecanemab data at the AIC showing a long-term benefit due to its specificity for neutralizing protofibrils. What's the read-through for ACU193?

Thanks, Ananda. Eric, you want to address that question?

Yeah, so as far as the pTau217, great question. Intuitively, you would sort of think that, well, this is a form of pTau, so it should correlate with tau PET. As it turns out, it's such a sensitive early marker, it actually tends to correlate with amyloid PET, which is not as sensitive. So what we've actually done in our trial is to use pTau217 as a screening measure for people who go on then to PET or CSF. And what we found is by doing that, we reduced the number of negative PET scans and negative CSF by about 50%. So it seems to be working quite well as a screening procedure, and we actually think that that's something that could play out in clinical practice, that a physician would get some from blood pTau217, and who otherwise would go on to have a negative PET scan. So I think it's a really good biomarker. And I'm sorry, I didn't quite catch your second question.

You know, with the lecanemab long-term study, they are showing that patients have this continued benefit based on their ability to target protofibrils. So what's the read-through with sabirnetug?

Well yeah, so we've followed that very carefully, and there's really interesting data. And I think what the field is learning, and we're learning along with the field, is that if you just look at amyloid based on PET scans, it's a very slow increase once you've reduced the amyloid that's there. But what you also see is that apparently PET scans are not that sensitive, because some of the other pathologies, increases in GFAP, increases in various forms of pTau, those things come back a lot sooner than your PET scan gets worse. And so in our view, that's a good indication that partly because or maybe because lecanemab targets these protofibrils, when you stop treatment with it, the pathology comes back relatively quickly, and you don't pick that up just based on an amyloid PET scan. And we think that's completely consistent with our hypothesis of targeting these soluble oligomers.

Got it, thanks. Very interesting.

Thank you. Ladies and gentlemen, I'm showing no further questions in the queue. I would now like to turn the call back to Alex for closing remarks.

Great. Thanks everyone for joining the call today, and for your interest in the company. Please don't hesitate to reach out to us if you have any follow-up questions, and have a great day!

Ladies and gentlemen, that concludes today's conference call. Thank you for your participation. You may now disconnect.