Acumen Pharmaceuticals (ABOS) 2026 年第二季法說會：ALTITUDE-AD 數據預計 2026 年底公布

Acumen Pharmaceuticals (NASDAQ: ABOS) 的 2026 年第二季財報電話會議重點放在 sabirnetug 即將公布的 ALTITUDE-AD 二期臨床試驗數據。該公司同時公布擁有 1.102 億美元的現金及有價證券，管理層預計這足以支應目前的營運與臨床活動至 2027 年年初。

重點摘要

• Acumen 仍預計於 2026 年底公布 ALTITUDE-AD 二期臨床試驗的頂線數據（topline results）。
• 頂線數據預計將包含主要療效終點 iADRS、CDR-SB、安全性與 ARIA 發生率，以及體液和影像生物標記。
• 第二季研發費用為 2,780 萬美元，管理費用（G&A）為 470 萬美元。淨虧損總計 3,270 萬美元。
• 截至 2026 年 6 月 30 日，現金及有價證券為 1.102 億美元，預計可提供維持營運至 2027 年年初的資金續航力。
• 在非人類靈長類動物中，ACU401 在前額葉皮質的暴露量比未經修飾的 ACU234 高出高達 40 倍。Acumen 繼續以 2027 年年中提交其主導增強型腦部遞送（EBD）候選藥物的研發新藥申請（IND）為目標。
• 預計於 9 月 16 日舉行線上投資人關係日，在二期數據公布前審視 sabirnetug、EBD 計畫及 Acumen 的投資論點。

關鍵財務數據

業務與營運績效

ALTITUDE-AD 逼近關鍵的二期催化劑節點

ALTITUDE-AD 正在評估 sabirnetug 在 35 mg/kg 及 50 mg/kg 劑量下相較於安慰劑為期 18 個月的療效。這兩個活性劑量均處於先前證實能達到藥效學標的結合的暴露量範圍內。

主要臨床療效終點為 iADRS，這是一項結合認知與功能結果的綜合指標。管理層預計 2026 年底公布的頂線數據也將包含 CDR-SB、不良事件、ARIA 發生率，以及體液和影像生物標記。

Acumen 表示，其一期試驗顯示在給藥三次後即展現對 β-澱粉樣蛋白寡聚體的標的結合與生物標記改變。管理層相信 sabirnetug 能提供具差異化的效益風險特徵，因為它能選擇性結合可溶性 β-澱粉樣蛋白寡聚體，且採用效應功能低於 IgG1 抗體的 IgG2 抗體格式。

增強型腦部遞送產品線取得進展

Acumen 在與 JCR Pharmaceuticals 的合作中，指定 ACU301 和 ACU401 為增強型腦部遞送（EBD）候選藥物。ACU301 結合了 sabirnetug，而 ACU401 則結合了下一代寡聚體選擇性抗體 ACU234。

在非人類靈長類動物中，所有三種測試的 EBD 雙特異性抗體均實現比未經修飾的 ACU234 更高的腦部暴露量。ACU401 在前額葉皮質的暴露量高出達 40 倍，且在深層腦區的暴露量也有所提升，同時保持對可溶性 β-澱粉樣蛋白寡聚體的選擇性，並擁有良好的血液學安全性。

該公司正在繼續推進這兩種候選藥物的工作，但預計將根據最佳的整體表現選擇其中一種推進至臨床開發階段。候選藥物的優化包括轉鐵蛋白受體親和力、單價與雙價格式比較、腦部運輸及潛在貧血風險。

管理層指引

• ALTITUDE-AD 的頂線數據仍預計於 2026 年底公布。
• Acumen 預計目前的現金資源足以支持臨床與營運活動至 2027 年年初。
• 該公司繼續預計於 2027 年年中為其主要 EBD 候選藥物提交研發新藥申請（IND）。
• 管理層正在開展三期臨床準備工作，旨在若二期結果成功時能縮短接續的時間間隔。關於三期設計的最終法規協商工作仍取決於 ALTITUDE-AD 的數據。

風險與關注焦點

• Acumen 尚未公開 ALTITUDE-AD 兩個活性劑量組的詳細統計考驗力（statistical powering）或分析假設。管理層表示這兩個劑量都有可能展現出療效。
• 投資論點很大程度上仍取決於 2026 年底公布的二期數據，包含臨床療效、安全性、ARIA 發生率及生物標記發現。
• ACU301 與 ACU401 之間的抉擇尚未最終確定，初始臨床研究設計也仍在討論中。
• 管理層尚未決定 EBD 計畫是要從健康志願者開始，還是直接進入患者試驗，儘管其目標是在可行範圍內儘快推進至患者試驗。
• 數位分身（digital twin）分析以及像 MTBR-tau243 這樣更新的生物標記仍屬於探索性質，初期可能利用儲存的樣本進行回顧性評估。

分析師問答亮點

• ALTITUDE-AD 數據公布：管理層證實，頂線數據應包含 iADRS、CDR-SB、體液與影像生物標記以及安全性指標，而不僅僅是主要終點。
• 三期試驗準備情況：Acumen 正積極進行 CMC（製造與管制）、合作夥伴討論及試驗中心相關規劃，但關於三期設計的最終法規對談仍取決於二期結果。公司希望積極的數據能支持開展單一關鍵三期試驗。
• 安全性差異化：管理層強調 sabirnetug 的寡聚體選擇性與 IgG2 格式是降低免疫活化與實現差異化 ARIA 特徵的潛在原因，但仍需視 ALTITUDE-AD 的結果而定。
• 生物標記：p-tau217 已用於患者篩選，並將作為結果指標進行評估。儲存的血漿樣本可能有助於日後分析 MTBR-tau243 及其他新興的血液生物標記。
• 數位分身：與 Unlearn.AI 的合作被用作探索性終點，以評估其在患者篩選中的潛在應用，並在未來分析中作為預後共變數。
• 聯合療法策略：管理層將聯合治療視為阿茲海默症潛在的長期發展方向，並將在推進其 β-澱粉樣蛋白寡聚體產品組合的同時，評估結合針對 Tau 蛋白或抗發炎療法的機會。

完整財報電話會議紀錄

完整財報電話會議逐字稿

管理層陳述

Operator

Good day, and welcome to the Acumen Pharmaceuticals Second Quarter 2026 Conference Call and Webcast. [Operator Instructions] Please note this call is being recorded.

I would like to turn the call over to Alex Braun, Head of Investor Relations. Please go ahead.

Alex Braun

Thanks, Michelle. Good morning, and welcome to the Acumen conference call to discuss our business update and financial results for the quarter ended June 30, 2026. With me today are Dan O'Connell, our Chief Executive Officer, and Matt Zuga, our CFO and Chief Business Officer. They will have brief 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 Investors 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. You will see Slide 2 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.

So with that, I'll turn the call over to Dan.

Daniel O'Connell

Great. Thanks, Alex. Good morning, everyone, and thanks for joining us today. During the second quarter, our focus remained on disciplined execution as we advanced sabirnetug towards the highly anticipated topline readout from our Phase II ALTITUDE-AD trial, which we continue to expect late this year. We believe this will be an important efficacy readout in the Alzheimer's field. ALTITUDE-AD remains a critical test of our central scientific thesis that selectively targeting synaptotoxic amyloid-beta oligomers may offer a differentiated approach to treating Alzheimer's disease. A substantial body of evidence supports this hypothesis, and we are excited by the opportunity to evaluate that thesis in a well-powered, randomized Phase II study with clinically meaningful endpoints.

Our Phase II results have the potential to substantially expand on our Phase I results, which included demonstration of A-beta oligomer t arget engagement and biomarker changes that we're seeing as early as 3 months of treatment, as we previously reported. We continue to be encouraged with the engagement of patients, caregivers, investigators, and study sites participating in ALTITUDE-AD, as well as in its 12-month open-label extension study. Their commitment has been instrumental in bringing us to this important inflection point. I believe the strong relationships the Acumen team holds with study sites and investigators is particularly supported by Acumen's patient-centric approach.

At AAIC last month in London, we presented patient experience data collected from participants and study partners prior to treatment in ALTITUDE-AD. Results illustrate the diverse ways individuals with early Alzheimer's disease experience, respond to, and cope with cognitive and functional changes, underscoring the importance of capturing patient experience directly to better understand the meaningful benefit at this stage of disease. As we previously described, ALTITUDE-AD was designed to detect a statistically significant difference on its primary clinical efficacy endpoint, iADRS, after 18 months of treatment with sabirnetug compared with placebo. We expect the topline dataset to include results from the primary endpoint, key secondary measures such as the CDR-SB, safety assessments including adverse events and ARIA rates, as well as important fluid and imaging biomarkers.

The study is evaluating two dose levels, 35 mg/kg and 50 mg/kg, compared with placebo. Both these dose levels are within the exposure range previously shown to achieve pharmacodynamic target engagement. While we remain focused on execution and preparation for the readout, enthusiasm across the organization continues to build as we approach this landmark catalyst. We believe that sabirnetug has the potential to demonstrate a differentiated benefit-to-risk profile given its unique product attributes as an anti-A-beta oligomer IgG2 monoclonal. We look forward to sharing the results later this year.

In the second quarter, we announced the nomination of two enhanced brain delivery candidates for the treatment of Alzheimer's disease, representing the only program combining a validated blood-brain barrier penetrating technology with an anti-A-beta oligomer-selective therapeutic antibody. Building on robust preclinical data from both in vitro and in vivo studies, we exercised our options with JCR Pharmaceuticals and will advance two candidates, ACU301 and ACU401. ACU301 is a bispecific antibody incorporating sabirnetug, and ACU401 incorporates a novel next-generation A-beta oligomer-selective antibody with differentiated properties. This is known as ACU234. We view our EBD program as expanding the optionality in our pipeline and will continue to evaluate both candidates in the lead-up to support a filing of an IND. Confirming our mouse data in non-human primates is a pivotal step in this work.

At last month's AAIC conference, we presented data showing that after intravenous dosing, all three EBD bispecific antibodies achieve greater brain exposure than unmodified ACU234 alone. ACU401, in particular, achieved up to a 40-fold greater frontal cortex exposure in non-human primates and significant increase in exposures in deep brain regions. The degree of brain penetration observed in cynomolgus monkeys, combined with preserved soluble A-beta oligomer selectivity and a clean hematological profile, exceeded our expectations and gives us confidence in the differentiated potential of our EBD program's approach. We continue to anticipate an IND filing for our lead EBD candidate in mid-2027.

Coming up, I'd like to flag for investors an anticipated virtual Investor Relations Day to be held on September 16. Please mark your calendars to view live or as a recording, as we hope this will be a helpful review for the Acumen investment thesis prior to ALTITUDE-ADPhase II data readout. The advance of sabirnetug and our next-generation blood-brain barrier EBD candidates underscores the strength of both our scientific platform and our ability to execute, positioning us well for a significant, eventful remainder of 2026. I look forward to updating you on our program and on our Phase II results for sabirnetug late this year.

And with that, I'll turn the call over to Matt.

Matt Zuga

Thank you, Dan. As a reminder, our second quarter of 2026 financial results are available in the press release we issued this morning, and in our 10-Q we will file later today. We ended the second quarter with $110.2 million in cash and marketable securities on our balance sheet, which is expected to support our current clinical and operational activities into early 2027. R&D expenses were $27.8 million in the second quarter. The decrease over the prior year was primarily due to reductions in manufacturing and materials costs as well as CRO costs as we get into the final leg of our clinical trial.

G&A expenses were $4.7 million in the second quarter, roughly flat for the same period in the prior year. This led to a loss from operations of $32.6 million and a net loss of $32.7 million in the second quarter. We are confident in our scientific innovation and strong track record of execution as we work toward our Phase II ALTITUDE-AD readout later this year and advance our EBD program. We remain dedicated to building value with our portfolio of A-beta oligomer-targeted antibodies for Alzheimer's patients, caregivers, and stakeholders.

And with that, you can open the call for Q&A. Operator?

Operator

[Operator Instructions] Our first question comes from Paul Matteis with Stifel.

分析師問答

Matthew Ryan Tan

This is Matthew on for Paul. I guess another company doing an oligomer-specific approach read out some blinded data recently. Maybe can you talk about like what are the differences between their approach versus yours and trial design, and how much can we, you know, kind of read through on their clean safety to your upcoming data?

Daniel O'Connell

Hey, Matthew, thanks for the question. Yes, we saw the announcement of the blinded interim assessment, but this is really early-stage data. So there's not too much we can conclude from that reporting or that announcement. And we'll be interested to see how that study reads out sometime early next year. We reported Phase I results in 2023, which, to our view, established a really robust clinical target engagement of A-beta oligomers. And with just 3 doses in that Phase I study, we're seeing effects on both fluid and imaging biomarkers that sort of exceeded our expectations and underpin our confidence in why in a large study, in an efficacy-based study such as ALTITUDE-AD, sabirnetug is positioned for success.

Matthew Ryan Tan

Okay. And maybe a quick follow-up. In the selection of your EBD candidates, what were the parameters that you sought to optimize? And where do you think your second molecule might be better than the bispecific sabirnetug?

Daniel O'Connell

Thanks. I can quickly comment. I mean, I think for our EBD program, we envision from a product profile standpoint, subcutaneous administration as a convenient form for delivery, as well as preserving the oligomer selectivity, potentially enhancing that selectivity, and an efficient transport across the blood-brain barrier using the transferrin carrier technology as partnered with JCR. So I think we're looking at safety, efficacy, and broader exposure in a format that would lend itself to convenient sub-Q dosing. So both of the candidates have, at least so far, demonstrated all of those attributes, and some of that data has been presented at meetings, and we'll continue to report on findings in that program as we march towards an IND filing on a lead sometime in mid-'27.

James Doherty

Matthew, this is Jim. Maybe I can add a little bit to what Dan has been saying. Of course, when you see the candidates that we announced, those represent the sort of culmination of a process. And we had a really robust collaboration with JCR. And what it allowed us to do is really look at a bunch of different parameters for optimizing for the right fit to match the carrier and the cargo to come up with the final product. And so we looked at a number of things. We looked at affinity for TfR. We looked at valency, monovalent versus divalent. We looked at a bunch of parameters around the potential risk for anemia and things like that. And so it really represents the culmination of a whole campaign to optimize for what we think is the best fit to deliver these oligomer-targeting antibodies into the CNS.

Operator

Our next question comes from Jason Zemansky with Bank of America.

Jason Zemansky

You described ALTITUDE, I guess, as designed to detect a stat-sig difference in iADRS, but with two active doses, can you clarify the framework and whether each dose is independently powered against placebo? If only one succeeds, under what circumstances would constitute a statistically robust positive study? And then a quick follow-up, please.

Daniel O'Connell

Thanks, Jason. Good question. As we have not specifically provided details on the powering and the analysis. I think, I don't know that we can go into greater detail on that this morning. Yes, we do have both doses, both of which have demonstrated target engagement. We think both of these doses could emerge as efficacious doses, and we'll be looking forward to providing more information as we get closer to the data readout later this year.

Jason Zemansky

Got it. And then maybe without getting too much into the efficacy bar, can you speak to the work you're doing now to minimize the interval between the Phase II results and the initiation of a Phase III? Any regulatory engagements, CMC, partner discussions, site planning? Which activities are sort of gated until the data?

Daniel O'Connell

Thanks, Jason. Well, you can imagine there are elements of everything that you mentioned that are ongoing now, with the exception perhaps of regulatory interactions in terms of establishing the Phase III design and so forth. But there's a lot of activity and anticipation to minimizing the white space. And we're hopeful for a successful readout in ALTITUDE-ADthat really will help facilitate and accelerate our ability to move sabirnetug into a single pivotal Phase III.

Operator

Our next question comes from Pete Stavropoulos with Cantor.

Samantha Schaeffer

Hi, this is Samantha on the line for Pete. My first question is there are biomarker data that suggests certain tau fragments like p-tau217 can be used as a marker for amyloid pathology, while markers like MTBR-tau243 identifies tau tangle pathology in Alzheimer's disease. I know that you've incorporated and will look at p-tau217 in the ALTITUDE-ADstudy, but can you talk about tau243? Do you plan to look at it in ALTITUDE, and how could you incorporate it into a Phase III? Can it be leveraged to help or expedite patient selection?

Daniel O'Connell

Thanks, Samantha. Go ahead, Eric.

Eric Siemers

Yes, so this is Eric Siemers. Maybe I can take that one. So, yes, the biomarker world in Alzheimer's is moving really quickly, especially with regard to blood-based biomarkers. As I think you probably know we use p-tau217 as part of our screening procedure actually for enrolling people into ALTITUDE, but it'll also be an outcome measure that we'll look at after we're unblinded at the end of the study.

MTBR is relatively newer, and so it really wasn't being discussed at the time we designed ALTITUDE. But one of the things that we have talked about is that, we have, a large number of patients and a lot of actually plasma samples that will be stored. And so we have the opportunity to look at things like MTBR, new biomarkers that, especially the blood-based biomarkers, that become interesting after we actually complete the study.

So yes, MTBR is one of the things we talk about, but I think it's not just that. Any other new blood-based biomarker that may look interesting, we'll have the opportunity to look at.

James Doherty

And Samantha, this is Jim. Maybe just to add a little bit onto what Eric is saying. I think he's totally right. It's really an exciting time in the field for looking at these fluid-based biomarkers. And the reason for that is it really provides a lot of information about patients. And so I think what we're seeing is people are beginning to measure these multiple markers in a lot of different studies, looking at a lot of different things. It potentially gives you the opportunity to look at where a person is in their progression with disease. It has the ultimate potential, I think, to start identifying patients who might be better candidates than others.

I think we're too early days for those kinds of applications, but I do think that's where the field is going. And so what we'll do exactly as Eric is saying, is as we go along, we'll continue to monitor all this. We'll use these tools as we can in our trials, and we have the opportunity to go back and measure some of these things, even in a post hoc fashion. So I think this is going to continue to be an important part of Alzheimer's trials moving forward.

Samantha Schaeffer

Awesome. And just one quick follow-up. In July, there was an announcement of a collaboration with Unlearn utilizing digital twins. Can you help us understand what this tool is and how it's incorporated into the Phase II, and how can you possibly leverage it for Phase III?

James Doherty

Yes, absolutely. This is Jim again. I'm happy to take that one. As you say, we have partnered with a company called Unlearn.AI to use these digital twins. And we see it again as another tool, another emerging tool that potentially provides some value. Essentially, these are almost individualized digital models relying on the data from thousands and thousands of patients who have been studied for the progression of their disease in clinical trials and in other formats. And so at this point, there's a tremendous amount of data about how disease progresses over time. And of course, it's incredibly complex and differentiated patient to patient. But what these tools do is allow for using baseline data to predict how their individual course of disease will progress over time.

It's a model, and I think there have to be lots of questions about how robust the models are, what you can say about them, what you can't say about them, but potentially, they have the opportunity to do things like allow you to refine your patient selection. They have the opportunity to do things like be used as a prognostic covariate in analyses following trials. And I think there are a number of potential applications, but honestly, the only way to really evaluate how much value these things have is to begin to get in there and work with it yourself. And so that's effectively what we're doing.

We're using this at this point as an exploratory endpoint. We're trying to understand how these tools might be useful to us in the future. And I think, as I was saying, there are several potential ways they can be used. So that's what our evaluation will be to understand which ones are the best ways to apply this technology for Acumen.

Operator

Our next question comes from Thomas Shrader with BTIG.

Thomas Shrader

A little background or next steps on the EBD franchise. Do you anticipate you would take both candidates into humans? Do you have to start with healthy volunteers? And any sense of how many patients or people you would need to get a read on anemia?

Daniel O'Connell

Thanks, Tom. Jim, why don't you take that one as well?

James Doherty

Yes, happy to. Some great questions, Tom. These are things that the team is actively working on at this point. To the first question, we have identified and nominated two candidates, ACU401 and ACU301. We're doing work on both molecules, and it really is intended to identify which one offers what we think is the best overall profile. So what we would intend to do is move into clinical development with one molecule, and that'll be the one that we think offers the best of possible profiles.

As far as additional work that we're doing, there's a tremendous amount of work on CMC and on tox study preparation in preparation for our plan to file an IND in mid-2027. And, I think we're still working on study design. There's a lot of active discussion around it. We've got a lot of experience from the INTERCEPT-AD study with sabirnetug that is going to help us identify what's exactly the best trial design to use. I think what I could say at this point is it's really going to come down to what's the most efficient design. We are going to try to get as much information as we can as we did in the INTERCEPT-AD study, but we also wanted to move this exciting program forward as quickly as we can. So more details later on what those design choices are going to turn out to be. But I can tell you there's a lot of active discussion right now with the program team trying to land what is going to be the most efficient design.

Thomas Shrader

And are you going to start in healthy volunteers or are you not saying?

James Doherty

So, that's one of the things that we're going to see. I think the goal is to transition to patients as quickly as we think is practical because you get a lot of valuable information from patients, as in INTERCEPT-AD. But I think, exactly when that would be is honestly one of the things that we're still talking about. So, yes, I just, we haven't really made a final decision yet.

Thomas Shrader

And one quick one for Dan. Do you expect to go radio silent at some point? And any guidance about when?

Daniel O'Connell

So, Tom, we continue to be convinced we'll have the topline results for ALTITUDE-AD late '26, consistent with our guiding for some time now. We have mentioned, as I mentioned on the call, we'll have an Investor Relations Day, September 16. And that'll be a forward-looking public-facing discussion. We anticipate participating in some of the early fall activities. So we'll be visible and accessible at some point as we get closer to the end of the year. In the fourth quarter, I think we will probably have to shut down some of our public-facing engagement in anticipation of results. But the timing and specific dates for that, can't comment on.

Operator

Our next question comes from Geoff Meacham with Citi.

Geoffrey Meacham

I have two quick ones. The first, I know the focus on oligomers obviously differentiates you from Kisunla and Leqembi, but how would you set expectations on safety and tolerability and the differences there? I guess, particularly as we get more real-world experience with these two agents in the industry commercially.

Second question, I want to get your view of the recent competitor tau data when you kind of think about the post-ALTITUDE-ADdata. Is there a way to fast track perhaps a combo proof of concept if you think that's a viable strategy?

Daniel O'Connell

Thanks, Geoff. Good questions. I think in terms of safety, tolerability, and sabirnetug, as we described, ALTITUDE-ADwith two active doses is intended to demonstrate a clinical efficacy signal and a risk-benefit profile, both inclusive of the clinical efficacy relative to safety that is differentiated from existing treatments. So we're hopeful and enthusiastic about that possibility. And really just the magnitude of the study, the duration of exposure, we think it's a well-designed study to underpin and validate the oligomer hypothesis as we've positioned it. So that's sort of our expectations for sabirnetug and ALTITUDE.

I think that you mentioned the, I think that you're referring to the Biogen BIIB080 program that was reported at AAIC in July. And I think those are interesting data. It looks as though they'll move into a Phase III study for that molecule. And I think it serves as, depending on how you view it, the first clinical validation of a tau-directed approach. Ultimately, I think we take the view that Alzheimer's is a disease that will be more adequately addressed with combination strategies. So we'll continue to evaluate ways to leverage not only our portfolio of A-beta oligomer-directed approaches or treatments with other potentially synergistic combinations whether it be tau or anti-inflammatory approaches, but it just sort of underpins sort of the stage we're at in terms of establishing better treatment options for patients.

We think the future is quite bright for safer, more efficacious, and more robust treatment for the early stages of the disease. And as I'm sure folks on the call are aware, the move into the preclinical population, and hopefully a way to avert or otherwise delay the onset of symptoms. So it is a really robust innovation ecosystem right now in the space, and we think that will continue to accelerate both commercially with products being adopted and grown in the marketplace and then with further research innovations that will continue to build on better options for patients.

Eric Siemers

Yes, and this is Eric. If I could just expand on that a little bit. In terms of safety and tolerability, there's sort of two aspects of that that are differentiated with sabirnetug. So first of all, it's the target. It's very selective for oligomers rather than plaque, and we think that that has some potential benefits in terms of safety. And the other thing that is important to keep in mind, I think, is that this is an, what's called an IgG2 antibody rather than an IgG1 antibody. Without going into too many details, the IgG -- all the other monoclonal antibodies are IgG1s, and they have more what's called effector function.

In other words, they call in your immune system to get rid of things that you don't want there. In the case of these monoclonals, it's typically plaque. And that can lead to problems like ARIA. But for an IgG2, there's less of this effector function, so it's less effect on calling in immune cells. And for our mechanism, targeting oligomers, you really don't need that to happen anyway. So there's two reasons to think that our safety and tolerability could be quite good. One is that we have this differentiated target, oligomers, and the second is that we have an IgG2 antibody with less effector function and less immune system activation. So we're looking forward to seeing the data from ALTITUDE, obviously.

Operator

Our next question comes from Dev Prasad with Lucid Capital Markets.

Dev Prasad

Just a couple of follow-up questions. First is to follow up on the biomarker data question. Will that biomarker data be in the topline release or will it follow later? And the second is, what should we expect from September 16 IR Day? Will it include new EBD data or a preview of ALTITUDE-ADanalysis plan or a venue to select EBD lead candidates?

Daniel O'Connell

Thanks, Dev. So for your first question, the topline results, as I mentioned in the prepared remarks, will include the primary outcome, the iADRS, which is a composite including both cognitive and functional measures involving the ADAS-Cog as well as the ADCS Activities of Daily Living. We'll also have the CDR Sum of Boxes, again, another cognitive functional endpoint familiar to the agency and others in the field. We intentionally will include both fluid and imaging biomarkers as part of those topline results. We really want the ALTITUDE-ADreadout to be a robust readout that really determines sabirnetug's safety and clinical efficacy as part of the study design. So, yes, we do anticipate having both imaging and fluid biomarkers with the topline results late this year.

Alex Braun

And then for IR Day, yes, so I would expect that to be more of a review of the investment thesis of Acumen. So whoever would like to get up to speed on sabirnetug and our EBD program prior to that Phase II data, that would be a good event for, viewers to tune into. So, yes, please keep it on your calendar.

Operator

I'm showing no further questions at this time. I'd like to turn the call back over to Alex Braun for closing remarks.

Alex Braun

Thanks, Michelle, and thanks to everyone for tuning in today. As always, we are at the company for follow-up questions, and I hope everyone has a wonderful day.

Operator

Thank you for your participation. You may now disconnect.