Earnings Call Transcript - ALXO Q3 FY2025

Operator

Greetings and welcome to the ALX Oncology Third Quarter 2025 Financial Results Conference call-in webcast. At this time, all participants are in a listen-only mode. A question-and-answer session will follow the formal presentation. If anyone should require operator assistance during the conference, please press star zero on your telephone keypad. Please note this conference is being recorded. I would now like to turn the conference over to your host, Jason Leppman. Please go ahead, sir.

Jason Lettmann, CEO

Thanks, everyone, and welcome to our Q3 2025 results. I appreciate everybody spending some time with us this morning, and I'm looking forward to this update. On slide two here, before we start our presentation of housekeeping, here are our forward-looking statements for your review. So on the next slide, slide three here, here is the agenda and our plan for today. we're going to be providing an update on our key accomplishments in the third quarter of 2025. Most notably, we are very excited to share with you the data set that will be presented at CITSI this weekend from a pre-planned analysis of our ASPEN-06 trial that showed CD47 expression as a key predictive biomarker for increasing durable clinical response with avorpicept in HER2-positive gastric cancer patients. So, our goals for today are most importantly to share these detailed results with you as we believe this data set now clearly validates the role of CD47 in HER2-positive cancers. We will then give you a sense of how this data now impacts our development strategy for Vorpicep going forward. We will also be providing an update on our novel ALX 2004 EGFR-targeted ADC, which is now in the clinic. Today, we are also excited to be joined by Dr. Peter Schmid from BART's Cancer Institute in the UK, who is a key opinion leader in breast cancer and investigator in our avorpisept phase 2 breast cancer study. He will be presenting his views on avorpisept data and its potential within the current treatment paradigm for HER2-positive metastatic breast cancer. Then, our CMO, Barb Kwinke, will provide an update on our novel EGFR-targeted ADC, ALX2004, which is currently dosing patients in our Phase I trial. Now, on Slide 4, in the third quarter, we made significant advances in both the Vorbicept and ALX2004 clinical programs. We, again, are excited to present the full data at CITSI that is demonstrating the potential of CD47 expression as a predictive biomarker and highlight a clear opportunity to now identify patients who are most likely to achieve the greatest benefit from EVO. As Barb will present in detail in her clinical section in this analysis, we saw that patients with high CD47 expression derived the greatest benefit across all key efficacy markers, response rates, duration of response, median PFS, and overall survival from the porpoiseps versus those with low expression. The data is very clear as the magnitude of benefit across many of these metrics was double or even triple those observed in the control arm and also clearly compare very favorably with the large benchmark studies in second-line gastric cancer. Most importantly, these results support the potential to pursue a targeted oncology approach to additional tumor types with EVO, and given the broad overexpression of CD47 in both solid tumors and heme malignancies, it gives us a real opportunity to really focus EVO now as a targeted IO therapy. Our phase two clinical trial of breast cancer, which is designed to pursue a CD47 and HER2 biomarker-driven strategy based on this strong data, is on track to dose its first patient this quarter. And as we've discussed, EVO has the potential to represent the first and only option for metastatic breast cancer patients who overexpress CD47, which we know can lead to worse outcomes and a poor prognosis for these patients. And with our second pipeline product, our novel EGFR-targeted antibody ALX2004, which is a highly differentiated ADC, we presented preclinical data and design of our phase one trial at the triple conference a few weeks ago. So, we're excited to announce today that we are currently enrolling patients in the second dose cohort. They're rapidly clearing the first dose cohort in this phase one trial. Turning to our financials quickly, we reported a total cash balance of $67 million, and that cash is expected to provide us runway into the first quarter of 2027, which positions us to achieve the value-enhancing data milestones for both ALX 2004 and of Orbisept that we have coming next year. Now turning to slide five, it has been very well established that CD47 is widely overexpressed across almost every type of cancer. And it is also clear that CD47 overexpression matters, as it is clearly a negative biomarker for patients. So when you look at research in CD47 over the last decade plus, it is a very strong foundation that CD47 is clearly a negative prognostic biomarker. And what you can see here is a meta-analysis of 38 cohorts across 17 publications, which includes over 7,000 patients. And there really is no question that CD47 is clearly associated with shorter survival and worse outcomes. And you can see on the right the wide range of tumor types where this has been established. Now, turning to slide 6, and as a reminder that during our Q2 call just a few months ago in August, we presented the top-line data which support that CD47 overexpression is a clear predictive biomarker for response with avorbicept in HER2-positive gastric patients. In this analysis, patients with both confirmed HER2 positivity and CD47 high expression had a dramatic response to Vorbicept as compared to those in the control group who did not have EVO. And as you can see here on the IPT population, we saw a strong response of a 41% ORR in the EVO arm versus 27% ORR in the control arm. And if you look at the data now in patients that clearly have CD47 high expression, there's a magnitude of benefit for those patients where we had an ORR of 65% in the treatment arm versus 26% in control with a nominal p-value of less than 0.05. Now, as you can see on slide seven, and what we're very excited to share with you now and at SITCY later today, this strong ORR benefit with Avorpisept in combination with TRP and CD47 high patients was also reflected and translated well to DOR, DFS, as well as survival, as it's clear that patients who overexpress CD47 and retain HER2 expression is driving the effect here. This is very important, as this clearly validates EVO's dual mechanism of action. And again, this is a second-line-plus gastric population, which has historically been a very tough cancer to treat. So in addition to the ORR benefit, which had a delta of almost 40% versus control, the median duration of response here for those patients is over two years, which is more than triple the control. The median PFS was over 18 months in the Evorpercept arm versus just seven months in control with an impressive hazard ratio of 0.39. And then we were also pleased to see these gains further translate to a benefit to overall survival where we saw a median OS of 17 months with EVO versus about 10 months in control and also a strong hazard ratio of 0.63. Barb will walk through this data in more detail, and the full data set will be shared at CITSE here soon. What is clear is that this data shows the potential for a Vorbicep to drive a really substantial benefit for these patients with high CD47 expression. On the next slide, this just shows the focus set of milestones that we're driving to now. In summary, we're laser-focused on these two programs. first, driving Evorpisept into acid breast, which is our study investigating patients post and HER2, and again, focused on CD47 high and understanding the impact of that biomarker. We continue to execute well against the milestones that we've communicated in the past and are anticipating first patient end Q4 of 2025, with interim data expected Q3-2026. ALX 2004 also remains on track and continues to proceed very well. We dosed our first patient in August of 2025, and we continue to expect initial safety data, first half of 2026. Turning to the next slide, and in summary, before I hand the call over to Barb, we had a strong quarter, both in terms of execution, continued tight discipline around our capital, and are excited about the key value catalyst for ALX in 2026. And as you can see here on slide nine, this is a snapshot of our current clinical pipeline. As we have communicated previously, we are pursuing a focused development strategy for EVO in combination with anticancer antibodies, given the consistent proof of concept that we have seen in various clinical studies with different monoclonal antibodies. And this data here today further builds on that. In addition to our HER2-positive breast cancer program with a CD47 biomarker-driven approach, AOX 2004, again, our EGFR-targeted ADC, continues to progress well. And we are also very excited about our partner program with Sanofi Sarqueza and multiple myeloma, which is now in dose optimization phase. So next, we'll turn this over to Barb, who will take over and provide more details on the avorpicep CD47 biomarker data presentation coming here at CITSI. Barb? Thank you, Jason.

Barbara Klencke, Analyst — Other

I will start by describing avorpicep's mechanism of action. CD47 is broadly overexpressed on cancer cells as a means of evading the immune detection, and it does so by sending a don't eat me signal. Avorpicep is a fusion protein, and it's designed to block that signal. Avorpicep's FC region is engineered to be inactive, and since it's particularly effective when given in combination with an anticancer antibody, such as receptin, the active FC domain on the anticancer antibody can then trigger very effective phagocytosis, which otherwise would have been suppressed by the CD47 signal. Slide 12 shows that the avoriceps approach to blocking CD47 is different from the conventional approach pursued by other CD47 targeted agents. While CD47 is overexpressed in cancer cells, it is also expressed in healthy cells, such as red blood cells. The conventional approach to block CD47 with an antibody that also binds to macrophages through an active FC has caused significant toxicities in some patients, and thus this approach has largely failed. In contrast, the avorficep approach using an inactive FC spares normal health, and our safety database in more than 750 avorficep-treated patients confirms the safety of this approach. Slide 13 shows the design of the Aspen 06 gastric study that Jason has introduced earlier. We enrolled 127 second-line or third-line HER2-positive gastric cancer patients, all of whom had received prior HER2-directed therapy. Patients were randomized to avorapicep, trastuzumab, ramicerumab, and paclitaxel, or the TRP alone. The primary endpoint was objective response. Importantly, because there can be loss of HER2 expression following prior HER2-directed therapy, we wanted to look beyond the HER2 status as diagnosed on archival tissue. Based on the known mechanism of action for avorpicep, our drug is not going to work as effectively if HER2 is not overexpressed on the cancer cell surface. To this end, ctDNA was obtained at baseline in all patients, and in addition, 48 patients underwent a biopsy, either at study entry or at some point following their prior HER2-directed therapy. In total, 95 patients, or 75% of the enrolled population, were confirmed as having retained HER2 positivity by either the ctDNA or on fresh biopsy. 90 of these 95 patients were valuable for CD47 expression in tumor cells using either archival tissue or, where available, a fresh biopsy sample. High CD47 expression based on a cut point of IHC3 plus staining in at least 10% of the tumor cells was present in 48% of these 90 patients. The expanded results of the pre-planned exploratory analyses of efficacy by CD47 expression level in patients who retained HER2 positivity is the focus of the data that I will review with you today. Slide 14 shows the objective response rate in key subsets. As we've previously reported, in the 95 patients who retained HER2 positivity, we see a robust response rate of 48.9% for the avorapicep CRP arm versus 25% in the control arm. And in the subgroup by CD47 expression level, avorapicep produced a response rate of 65% compared to 26% in the control arm amongst patients with the high CD47 expression levels. The response rate in the control arm was consistent across CD47 expression levels and lower than that in the avorapicep arm in both the CD47 and CD47 in the CD47 high and CD47 low groups. Moving to slide 15, I'm now displaying the duration of response in these same subgroups. Again, we see the potential of CD47 expression as a powerful predictive biomarker for a Vorpicep benefit. The duration of response in all HER2-positive patients, irrespective of CD47 expression, was 15.7 months for a Vorpicep plus TRP, compared to 9.1 months for responders in the control arm. In the CD47 high group, the duration of response was three times longer for patients in the avorapacet trastuzumab RP arm compared to the control, the median duration of response of 25.5 months versus 8.4 months. In the CD47 low group, avorapacet TRP had a median duration of response of 11.2 months compared to 12 months for TRP. In slide 16, we're now showing the progression-free survival in patients with confirmed HER2 positivity and high CD47 expression. The hazard ratio is 0.39, with a median TFS of 18.4 months for the avorapiceptratutumab RP arm, which is more than double the 7-month scene in the TRP alone arm, again suggesting the potential for CD47 expression as a powerful predictive biomarker for avorpicep benefit. Slide 17 shows a similar pattern of longer survival observed in the HER2 positive CD47 high avorpicep arm. Median overall survival was 17 months compared to 9.9 months for the control arm with a hazard ratio of 0.63. All of these data being presented at the CISTI conference this week are based on mature follow-ups. The median follow-up for survival, for example, was 25 months. Slide 18 shows some of the various cut points that we examined for CD47 expression based on the range and strength of IHC testing. As shown here, we looked at medium or high-intensity staining, defined as IHC 2-plus and 3-plus, in at least 10% and in at least 25% of tumor cells, and we also looked at high-intensity staining, or IHC 3-plus, in tumor samples with 5% or more, or 10% or more of cancer cells expressing that high-intensity staining. The prevalence of CD47 high across these ranges from 40% to nearly 60% of HER2-positive patients, depending on the cut point. The key takeaway from this slide is that we see consistent improvements in response rates, PFS, and OS in the avorpus set treatment arm, irrespective of the cut point for CD47 expression. On slide 19, I'm showing a cross-trial comparison of our Evorpus efficacy data in patients with retained HER2 positivity and high CD47 expression relative to benchmark trial data in HER2 positive gastric cancer. With the usual cross-trial comparison caveats in mind, Evorpus data directionally compares very favorably to recent INHER2 data from the DESTINY gastric O4 study in the second line setting. In that trial of nearly 500 patients published earlier this year in the New England Journal of Medicine, those patients required confirmation of HER2 status by fresh biopsy following a trastuzumab-containing regimen, and they randomized these patients to INHER2 or to RP as a control arm. As effective as a HER2 was in the second-line setting in that trial, our second and third-line of ORFACET data generated in patients with high CD47 expression, a known negative prognostic biomarker, appear much better. Turning our attention now from gastric cancer to HER2-positive breast cancer, slide 20 introduces a phase 1b2 trial in HER2-positive breast cancer patients conducted by JAS that evaluated the safety and efficacy of Avorpis Episani Datinab in patients who progressed on prior HER2-directed therapy. These patients were heavily pre-treated with a median of six prior lines of therapy. In nine patients confirmed to retain HER2 status by central assessment, the response rate was 56%. The median duration of response for that group ranged from 5.5 months to nearly 26 months, with the median not reached and the median PFS being 7.4 months. These data compare favorably to benchmark data, including, for example, the SILFIA trial, a predominantly second- and third-line HER2-positive breast cancer trial, which produced a response rate of 22% per margid 2 at Tuximab. Moving to slide 21, we've now demonstrated in these two studies the potential of the Vorpicep to engage the innate immune response, validating the mechanism of action of the Vorpicep given in combination with anti-cancer-directed antibodies in both HER2-positive breast cancer and in HER2- positive gastric cancer. This gives a strong conviction of the Vorpicep's potential and its path forward in the HER2-positive breast cancer setting, which we'll talk about next. Slide 22 describes briefly the opportunity that we see for avorpoceps in breast cancer, which now has a high probability of success, having been de-risked by the HER2-positive data set in two different HER2-positive settings. A CD47 HER2-positive biomarker-driven approach with avorpoceps enables a highly targeted strategy, potentially addressing the high-unmet medical need in the evolving breast cancer landscape, which includes patients who have now progressed on in HER2. It is now my distinct pleasure to introduce Dr. Peter Schmidt, a professor of cancer medicine and center lead at the Center of Experimental Cancer Medicine at Farts Cancer Institute. He's a well-known global lead investigator on multiple ongoing phase three trials in metastatic and localized breast cancer. Just two examples of trials with immunotherapy agents, he's a global lead investigator on the Pembrolizumab Keynote 522 study and the Atezolizumab Impassion 130 study. With that, I turn this over to you, Peter.

Peter Schmid, Analyst — Other

Thank you, Bob. The treatment options for patients with metastatic to positive breast cancer are currently undergoing, I would almost say, a dramatic change. We obviously have seen a very active drug moving initially into second and third-line treatment with Drostuzumab-Tiroxicon, but everyone is aware of the data that's now placing TDXD increasingly in the first-line setting, and I think that's where the drug will ultimately end up. That is fantastic from a patient perspective. We have a very powerful new first-line treatment option, but the challenge that comes out of this is there is no standard of care for patients who have been treated with trastuzumab durexacab. The sequence we had previously, that patients would get a treatment called TPH, first line with trastuzumab durexacab, and second line TDXD, and a third line of options, has just been turned upside down. So at the moment, there's a number of options we can choose from, but none of those options have actually been specifically approved and tested in patients with prior TDXD therapy. So the options we have to choose from is tucatinib, trastuzumab, in combination with capcitabin. Td1 is still an option. Some investigators, some clinicians may give chemotherapy and trastuzumab. Her2 TKIs play a smaller role and are increasingly less and less being used. But of course, we also hope that we have other her2-tigrant therapies. So there is a significant unmet need for patients with her2-positive breast cancer who have progressed on or after TDXD. And I can see that it will percept as a possibly exciting role to play. It has demonstrated activity in patients post-trastuzumab-deruchstagab in combination with other HER2 targeted agents. Now, if you look at what we would hope to see in such a situation, our challenge is to bring in new agents that can overcome the resistance to TDXD. The need for agents in the HER2-positive breast cancer space at this point is to define novel agents, ideally bring a different mechanistic approach to target HER2. And we can see for the Volpercept that it has a different mode of action by killing cells via enhanced ADCP versus the classic payload-based ADCs or other drugs we are currently using. The second thing we want to achieve is not to have a drug that obviously has demonstrated activity post-HER2-directed treatment after ADCs and after monoclonal antibodies. And the elephant in the room here is always trastuzumab. Now, we've seen from the data in the gastric study, but also in some of the HER2-pre-treated breast cancer studies, that Volpercept has shown activity post-trastuzumab in gastric cancer, and following up to four more lines of patients with HER2-positive breast cancer prior HER2 treatment. We would like to have a treatment that can supplement and enhance the current standard of care rather than replace the backbone treatment. And again, if you look at the way how Evolpercept works, it is really designed to work statistically alongside the key therapies, the key backbone, obviously, for HER2-target therapy is just Sousamal-positive antibodies. We are keen to have a drug that's safe and safer than ADCs. We had to learn over the years that ADCs have quite substantial possible toxicity, which is obviously driven by a payload as it is ultimately tied with chemotherapy. And the safety profile of Evolpacept is very different to what we know and seems to be much more favorable compared to some of the ADCs. Finally, having immune therapy agents that can really drive what we see sometimes in HER2-positive breast cancer, this long tail we, as clinicians often go on about, that is what ultimately patients need to have a long-term benefit in survival. And we feel that there's an immune component to that. We know already that there's a small percentage of patients who have very, very long survival on HER2-target therapy. But enhancing that immune effect by giving a CD47-targeted drug can possibly increase the tail for patients, that is at least my hope. If you look at CD47 as a selection strategy, and again, I think that is really important for this program, is that we're not going into this blindfolded. We actually have a very powerful biomarker, and as you have seen from the gastric data. It's a very clearly better signal for this concept in patients with high CD4-47 expression. Now, as you can see, there's a number of breast cancer studies that have looked into this, and I'm not going to go into each of those trials and the scoring methods in too much detail. The bottom line is about 1,000 patients, and they're relatively consistently showing a CD47 a high expression rate of around 50%, so 54% is the average if we go through those trials. And that's a substantial proportion of patients and actually allows us to drive that program forward without having a target group that is ultimately too small to select for clinical trials. Now, a couple of preclinical data I think are really interesting. Now, preclinical data, you may say it's a little bit nerdy, but I think it's really helpful for us to understand the biology. So if you look at this slide on the left side, you see the CD47 expression in HER2 positive breast cancer cells compared to HER2 negative cells. Green means low expression, red means high expression, this black or blue color is moderate expression. And it's very obvious to see that we have a higher percentage of CD47 expression in HER2 high disease. If you move to the right side of the slide, again, probably even more important for what we're aiming for. This compares the CD47 expression in primary disease on the right side and in recurrent disease, so pretreated disease on the left side. And again, it's very obvious that we have more positivity, CD47 positivity in tumors, and therefore in patients who have prior HER2 treatment and have recurrent HER2 positive breast cancer. And this is exactly the target population we're aiming for. If you then look at emerging data, and again, cell line-based data for cell lines that have been treated with trastuzumazeruxicam, And as I said earlier, this is the new standard of pair in the first-line setting. So our prediction for the future is all patients will have TDXD pretreatment. And we have to focus on patients who are persistent to TDXD. As you can see here in orange, these are cells that have been TDXD pretreated. In purple, DM1, and then in white is ultimately controlled. And it shows the percentage or the number of CD47-positive cells. And as you can see very, I think, impressively, is that we have a markedly higher expression of CD47 in cell lines that were prior exposed to trastuzumab-deruxtican, and that is the target group we're aiming for. So the target population is very clearly a substantial population of patients who have to cause breast cancer. The population is probably even bigger in patients who have prior CD47 pre-treatment. But it also may be one of the ways these tumor cells evade the ADC treatment effect, and therefore may be a really fantastic opportunity

Speaker 1

to target this clinically.

Peter Schmid, Analyst — Other

Now, the clinical trial that is ongoing, the ASCO trial you're very much aware of, is in my opinion, it serves one key focus. So as a clinician, I've asked that question before, I'm keen to see this move forward into a phase three as quickly as possible because we know it works, we know what the target population is, and we know there's a huge need post-TDXD. But what we don't know exactly is how to do the statistics for a phase three trial by having the exact response rate at PFS and other endpoints, which we obviously need to do to size up and design the Phase III trial properly. So this trial, therefore, is a non-randomized Phase II trial in patients with HER2-positive metastatic breast cancer, with measurable disease, with prior treatment with chastuzumab and are then offered treatment with in combination with chastuzumab and patients of a physician's choice chemotherapy. Very pragmatic design. This is the real world out there, but what we want to learn from this trial is really how the response rates are in patients who were CTDNA positive were too, but also what the duration of response TFS, overall survivalist, and in patients with CD47 high, but also CD47 low tumors to get further confirmation from the biomarker data. We have already obtained from gastric cancer, which ultimately allows us to fine tune the phase redesign going forward. Thanks, everyone. I would

Barbara Klencke, Analyst — Other

like to pass back to Barb, please. Thank you, Peter. Well, let me wrap up this section with a brief breakdown of the addressable patient numbers in the core markets. As you can see, there are roughly 48,000 breast cancer patients in the second plus line setting who are HER2 positive. Of that, we believe that at least 60 to 80 percent of these patients will retain HER2 positivity following prior therapy. Of that group, 50 to 70 percent will have high CD47 expression. As Peter highlighted, there are a number of publications to support that CD47 overexpression in HER2-positive breast cancer patients will be upregulated post-IN-HER2 treatment. We believe that this represents approximately 20,000 addressable patients who are both HER2-positive and CD47-high. If you boil this down and use conventional estimates on pricing, you get to roughly a $2 to $4 billion market opportunity, again, just in patients that are CD47 high and HER2 positive, representing a significant opportunity for a vorpicep. On slide 31, I now want to provide a quick update on ALX 2004, our EGFR antibody Drug Conjugate Program. As shown on slide 32, our company's first ADC, the ALX 2004 molecule, was a result of rigorous internal drug design process. Our goal was to create a best and potentially first-in-class drug designed to maximize the therapeutic window and to overcome the historic toxicity challenges that others have encountered in targeting EGFR with an ADC. With ALX 2004, we have optimized all three components to do this, including the payload, the linker, empty antibody to create a truly novel molecule against a very well-validated target. ALX 2004 uses metuzumab-derived EGFR antibody selected to minimize skin toxicity and to maximize the therapeutic window. Its binding epitope is distinct from the U.S. FDA-approved EGFR antibodies, such as ceteximab and panetumamab. Additionally, ALX 2004 has a proprietary linker payload and TOEFL-1 inhibitor payload engineered to offer improved linker stability for on-target delivery of payload and enhanced bystander effect. At the recently concluded triple meeting in Boston in October, we presented preclinical data highlighting these elements in greater detail. Moving to slide 33, here are the preclinical data highlights. Both in vitro and in vivo animal models support impressive dose-dependent activity and a differentiated safety profile. Importantly, non-human primate toxicology studies did not demonstrate EGFR-related skin toxicities at clinically relevant doses,

Operator

and there was no evidence of payload-related ILD in the animals.

Barbara Klencke, Analyst — Other

This overall profile supports our conviction that this molecule could potentially demonstrate efficacy with a manageable safety profile in patients. Slide 34 shows a snapshot of the efficacy data from our in vivo models. ALX 2004 showed regression and tumor suppression across a panel of xenograft models, representing a broad spectrum of cancer types and EGFR expression levels. Notably, ALX 2004 was effective in models harboring KRAS, BRAF, and P53 mutations. ALX 2004 shows excellent tumor suppression activity at doses as low as one milligram per kilogram, given either once or once weekly times three, leading to complete tumor eradication in several of the models. These results confirm the broad applicability of ALX 2004 in targeting EGFR-positive cancers. Slide 35 shows the key findings from our six-week repeat dose with six-week recovery period in the GLP non-human primate tox study. All findings were minimal to moderate and fully recoverable. Thus, these data support the design of the ALS 2004 study and the likely safety margin for clinical use. Slide 36 highlights our clinical development plan. We are targeting EGFR-expressing tumor types, namely lung, colon, head and neck, and esophageal squamous cell carcinoma in this dose escalation and dose expansion trial. We dosed our first patient in August, and we have completed our first dose cohort at 1 mg per kg without any DLT. We are currently dosing patients in our second dose cohort at 2 mg per kg. We are on track to provide initial safety data from the Phase Ia portion of the study in the first half of 2026. Our goal in this Phase Ia, Phase Ib trial is to identify the dose that optimizes safety and activity in tumor types, which we believe have the highest potential for success. These data will then set up the program well to advance into a future registration study. With that, I turn the call back over to Jason.

Jason Lettmann, CEO

Thanks, Barb, and thanks again to Dr. Schmidt for sharing his perspectives on the program as a KOL in the field. Again, Q3 was a strong quarter, both in terms of execution and new data. What we're most excited about now is driving a targeted IO breakthrough in a first-in-class drug with Evo, as well as our very encouraged by AOX 2004's fast start in the clinic and building momentum. In sum, our CD47 blocker has been successful, where no other has, both in terms of its manageable toxicity profile, as well as activity, as we've now demonstrated efficacy in a randomized study, and we've identified an actionable and predictive biomarker for response to EVO in our gastric cancer study. This further reinforces the benefit we have seen in terms of DOR, PFS, and OS, and again, this biomarker is on mechanism. Going forward, we're developing a CD47 biomarker, and therefore, it is really of no surprise to see that CD47 overexpression shows such a strong impact on our data. So, what this allows us to use is CD47 to select for patients in both current and future trials with the goal of replicating the results we have seen here with gastric cancer and demonstrating the same significant and transformational benefit for patients in our HER2 positive breast study. Again, there are no approved therapies for patients overexpressing CD47 and no options in late development to address this known path of evasion, but we remain focused on delivering for them. In 2004, there are also no approved EGFR-targeted ABCs, and although clearly a validated target, there remains a substantial unmet need for these patients as well. ALX 2004 is off to a very strong start in the clinic, and we believe also has the Potential to the redefined standard of care across a range of EGFR expressing cancers So with that, I'll open up the floor Q&A again. Thank you for the time this morning

Operator

Thank you. We will now be conducting a question and answer session if you would like to ask a question Please press star 1 on your telephone keypad a confirmation tone will indicate your line is in the question queue You may press star 2 if you would like to remove your question from the queue for participants using speaker equipment It may be necessary to pick up your handset before pressing the star keys. And again, that is star one if you would like to ask a question. And our first question will come from Lee Watzek with Cantor Fitzgerald.

Daniel Brander, Analyst — Cantor Fitzgerald

Good morning ALX team, this is Daniel Brander on for Lee. This is an exciting update and we're curious to hear your thoughts on how to correlate the CD47 positivity that you showed on slide 30 with the CD47 the kind of CD47 expression cutoffs that you showed in the gastric data on slide 18. What would you say is CD47 high in this context, and how should we think about the patient population that would be matching that in your trial?

Harish Shantharam, CFO

Thanks, Daniel. Appreciate the question. So, 30, just thinking about what we saw in breast or what we've observed in the literature versus gastric? Is that the question? Yeah, basically, yeah. Okay. Yeah. Well, yeah, it's a great question. I think it's one we've looked into. I think what we're really fortunate to have is a strong scientific basis behind CD47. And so what we see is really promising concordance across the two indications. So if you look at gastric, it was roughly 50-50 in terms of the CD47 high group. And I think then if you turn to the benchmarks, and again, this is where the strength of the science comes in, we see we have five different publications looking at the question of CD47 and specifically HER2-positive cancer. And, again, what we see is strong concordance there, too. And if you add those numbers up, it's roughly half, again. So five different studies supporting that, you know, around 50% of the patients will be CD47 high. And, interestingly, those different publications use different clones, different methodologies, et cetera. And so, yeah, I think that that's what gives us such conviction that this is, you know, translatable not only to breast, but frankly, a broad range of tumor types.

Daniel Brander, Analyst — Cantor Fitzgerald

And if I may, can I ask a follow-up question?

Speaker 9

Yeah, sure.

Daniel Brander, Analyst — Cantor Fitzgerald

How should we think about your companion diagnostic development? Are you doing that yourself in health? Are you using the same kind of Evorpercept construct, or are you using an independent antibody? Can you shed any light on that?

Harish Shantharam, CFO

Yeah, sure. I mean, I'll take it at a high level and then maybe ask Barb to weigh in on the path to a CDX. You know, we've done the testing with a partner for the gastric study, planned to do the same in breast. And then, of course, you know, as this data builds, and I think as we, you know, continue to understand the right cutoff and how this translates, we'll pursue further work. But, Barb, do you want to add to that?

Barbara Klencke, Analyst — Other

I would just say that the assay is a IHC. It's a research use assay that was applied to the gastric data. Our ongoing or our soon-to-be enrolling trial in breast cancer, the 80-patient single-arm trial, will use the same research-based assay. And then we are working already with partners to think about the operationalization of the process prior to the initiation of a Phase III trial so that we will be ready for a companion diagnostic. but, again, via a partner.

Daniel Brander, Analyst — Cantor Fitzgerald

Thank you so much for your time in answering my questions.

Speaker 9

Great. Thanks, Dana.

Operator

And our next question comes from Roger Song with Jefferies.

Speaker 1

Great. Thanks for taking the question. And very interesting data. Thank you for sharing this. Maybe related to the efficacy in the CD47 high population, do you have any data in your breast cancer trials with JAS and any new data, you can maybe give some comments on the CD47 high versus low. And then in terms of historical breast cancer, do we have any evidence for the CD47 high population, the traditional or the standard of care is performing less than the CD47 low population? Have you done any retrospective study as well? Because I know the benchmark is using the SOFIA or any other CD40, the HER2-chemo combo, but that's in the broad HER2-positive, not the CD47 cutoff.

Harish Shantharam, CFO

Yeah, no, those are both great, great questions, Roger. So, number one, in terms of the high versus low comparisons and the ZANI study, and frankly, broadly, I think those are great questions. So, this data and, you know, the way in which it's rippling through our development plan is relatively new, as you know, Roger. So, I think, you know, we're really excited about what we're seeing. It's incredibly strong in terms of CD47 high and gastric. There's no question it's driving the effect in that study. And so the natural question is, where else is this working? And I think whether it's the study with JAZ or our work with Sanofi or the other studies we have going with anti-cancer antibodies, we're very keen to understand that. So I'd say what we know is we're seeing a 56% overall response rate in patients post in HER2 that have seen a whole lot of HER2-directed therapy. And to your point around the margituximab comparator, it's well north of what you'd expect. And actually, there was recent data at ESMO that supports, again, you know, a relatively low response rate. There was a real-world study that was sub-20% in patients in terms of ORR post and HER2. So to see 56%, it's very strong. And I think, you know, your question on CD47 high versus low is one we're in the process of understanding. And then your second question on just benchmarking the data and what we see, you know, Barb had laid out the comparator with and HER2 in the Destiny Gastric O4 study. Certainly, if we were to line up the rainbow studies, to the best of our knowledge, the control arm is performing at bar with benchmarks across a number of different studies. And to your question, which, again, is a good one, you know, those benchmarks we think are the best they're going to be, right? Because we know CD47 high is a negative prognostic, and we know that those patients should do more poorly. And so, you know, to clear those benchmarks and compare well, and then also be armed with the knowledge that those patients probably, if we were to select from those studies, the CD47 high-only patients, they would do even worse. Certainly, you know, I think builds our conviction.

Speaker 9

Yeah, makes sense. Thank you. Thanks, Roger.

Operator

And as a reminder, if you'd like to ask a question, please press star 1. And we'll go next to Sam Sutsky with LifeSci Capital.

Sam Sutsky, Analyst — LifeSci Capital

Hey, good morning, everyone. Thanks for taking my questions. Just on the interims next year of both the EGFR ADT and the breast cancer program, the abort precept, curious on how many patients you're hoping to have in each other's data sets and then just how you view OWEN as you think about safety on the EGFR side and then just the delta of efficacy on the abort precept side.

Harish Shantharam, CFO

Yeah, both great questions. Thanks, Sam. I'll take 2004. I'll ask Barb to weigh in on the breast front. I think 2004, as you know, targeting EGFR, one of the most well-validated trodden targets in oncology, there's just no question that EGFR is affected. So I think it's led to a natural question from investors and partners, and that's, you know, can you target this target with an ADC when you have a payload involved? And as a reminder, again, I think we're very encouraged by what we see in the primate work. That tends to translate very well, and so far so good, right, to clear one MIG per KIG quickly, I think, is a strong start at already a relatively high dose. and now on to the next cohort, which, again, I think is moving fast, is what you want to see. So as we go into the next year, early next year, in terms of what we'll share, I think it depends, right, which is the reality of a dose escalation study. I think our goal is to answer the safety question as best we can in a phase one and then put up data that will answer that. And again, the study is marching very well here. And I think we feel, you know, we feel real confident that if this continues, of course, we'll be able to share something going into early next year. And then on the breast front, in terms of benchmarks, Barb, do you want to weigh in on that one?

Barbara Klencke, Analyst — Other

Yeah, I think, Sam, thank you. I think you were asking what might our expectations be both for number of patients as well as the bar. The bar I'll start with, there's a lot of data with trastuzumab and chemotherapy, which really is the backbone upon which we add a Vorpicep in our trial. Chemotherapy, trastuzumab, at best, will have about a 20% response rate. Interestingly, there was new data coming out of ESMO looking at the post-NHER2 setting, and response rates continue to drop, not unexpectedly. And as we noted, our trial will enroll all patients post-NHER2, where we do anticipate that CD47 overexpression becomes part of the mechanism of resistance. We attack that directly, and we anticipate having good outcome data in our Vorpicep trial. So I think the benchmark is going to be in the range of 15% response rates. Again, 20% might be the upper bound, but with the combination of the two things, the poor prognostic effect of CD47, as well as the evolving standard of care. And the fact that there really isn't anything that has shown up well post-invirtu really bodes well for us. What do we expect in our bar? I think, you know, doubling that would be nice, 35% to 40%. We certainly in our gastric data that I showed you did in the gastric setting did even better. and we anticipate that, you know, the opportunity is there to do quite well, but I think we would be very happy with a 35% to 40% response rate in our breast trial.

Speaker 9

Okay, thanks.

Operator

And this now concludes our question and answer session. I would like to turn the floor back over to Jason Lippman for closing comments.

Harish Shantharam, CFO

Great. Thanks, everybody. Really, really excited to share this data with you. We've continued good progress across both EVO and 2004, so real positive updates today. And, again, appreciate the engagement and support and look forward to future updates. Thanks so much.

Operator

Ladies and gentlemen, thank you for your participation. This does conclude today's teleconference. You may disconnect your lines and have a wonderful day.