Good day, everyone, and welcome to today's BioAtla First Quarter 2025 Earnings Call. At this time, all participants are in a listen-only mode. Later you will have the opportunity to ask questions during the question-and-answer session. It is now my pleasure to turn the conference over to Mr. Bruce Mackle of LifeSci Advisors. Please go ahead, sir.

Thank you, Operator, and good afternoon, everyone. With me today on the phone from BioAtla are Dr. Jay Short, Chairman, CEO, and Cofounder; and Richard Waldron, Chief Financial Officer. Following today's call, Dr. Eric Sievers, Chief Medical Officer; and Sheri Lydick, Chief Commercial Officer, will join Jay and Rick in a short Q&A. Earlier this afternoon, BioAtla released financial results and a business update for the first quarter ended March 31, 2025. A copy of the press release and corporate presentation are available on the company's website. Before we begin, I'd like to remind everyone that statements made during this conference call will include forward-looking statements, including but not limited to, statements regarding BioAtla's business plans and prospects, and whether its clinical trials will support registration, plans to form collaborations and other strategic partnerships for selected assets, results, conduct, progress and timing of its research and development programs and clinical trials, expectations with respect to enrollment and dosing in its clinical trials, plans and expectations regarding future data updates, clinical trials, regulatory meetings and regulatory submissions, the potential regulatory approval path for its product candidates and expectations about the sufficiency of its cash and cash equivalents to fund operations and expected R&D expenses. These statements are subject to various risks, assumptions and uncertainties that can cause actual results to differ materially and are described in the filings made with the SEC, including the most recent annual report on Form 10-K and subsequent quarterly reports on Form 10-Q. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of today, May 06, 2025, and BioAtla disclaims any obligation to update such statements to reflect future information, events or circumstances, except as required by law. With that, I'd like to turn the call over to Dr. Jay Short. Jay?

Thank you, Bruce, and thanks to everyone for joining us for our first quarter 2025 BioAtla earnings call. Details related to what we will share today are available in today's press release and our updated company presentation, both of which are available on our website. Also, the posters, which were recently presented at the 2025 AACR annual meeting are available on our website. Just a few short weeks ago, I provided updates on our conditionally active biologic or CAB platform clinical programs that we are advancing internally at BioAtla, as well as the clinical programs we are currently advancing toward corporate partnerships. All of these CAB-based programs are designed to increase both the potency and safety of our therapeutic candidates targeting solid tumors in areas of high unmet medical need. Today, I will begin with our Phase one dose escalation study evaluating the dual conditionally binding EpCAM and CD3 T cell engager. As a brief update to our call in March, the study is progressing well and the maximally tolerated dose has not yet been reached. We continue to observe multiple patients achieving tumor reduction and tolerating the therapy over many months without progression. Further, all three patients in the 100 microgram treatment dose cohort have cleared the dose limiting toxicity period. We have also dosed the first three patients at the treatment dose of 300 micrograms and we remain on track for our dose escalation clinical data readout in mid-2025. We also anticipate a data readout for the cohort expansion portion of the study in the first half of 2026. We continue to believe that our dual EpCAM CAB CD3 bispecific T cell engager has the potential to be at the forefront of a novel approach to harnessing the body's immune system to target and destroy cancer cells and has the potential to treat a wide range of metastatic tumors, including cancers of the colon, lung, breast, pancreas and prostate among others. Next on to our CAB-AXL-ADC Mec-V. Mec-V continues to demonstrate exceptional overall survival at the 1.8 mg/kg Q2W dosing regimen with a 2-year landmark survival of 59% in mKRAS non-small cell lung cancer patients. This is particularly compelling given the previous studies among patients treated with standard of care agents have reported a 2-year landmark survival of only less than 20%. We continue to observe a high correlation of AXL and mKRAS expression and the study follow-up is ongoing. Of particular note, we recently observed a similar exceptional overall survival using Mec-V across several subtypes of soft tissue sarcoma including leiomyosarcoma, undifferentiated pleomorphic sarcoma and liposarcoma with a 1-year landmark survival of 73%. Observing exceptional overall survival in two different heavily pretreated solid tumor types strengthens our conviction that Mec-V is fundamentally improving the natural history of the disease, enabling patients to live considerably longer regardless of the subsequent treatment they receive. We remain focused on positioning this asset for a future pivotal trial with Phase 2 data readout in the first half of 2026. Transitioning to the Phase 2 clinical programs that are planned for advancement through corporate partnerships, we remain committed to aligning with a partner that can maximize the value of these assets, and we are very encouraged by our active discussions with multiple potential collaborators. First, regarding our CAB-ROR2-ADC, Oz-V, we continue to observe a compelling signal in patients with metastatic HPV positive head and neck cancer. This group of patients represents a significant and growing segment of the head and neck cancer population with high unmet need. This large patient population is currently poorly served by agents that inhibit EGFR as well as other standard of care agents. More specifically, other studies using standard of care agents have reported ORR of only 0% to 3.4% among HPV positive head and neck cancer patients. As of the March 24 data cutoff, 11 treatment refractory HPV positive head and neck patients who had three prior lines of therapy treated with the 1.8 mg/kg Q2W dosing regimen showed a remarkable 100% disease control rate, a 45% overall response rate with 27% confirmed to date. We continue to collect data on duration of response, median progression free survival and median overall survival, all of which are ongoing and we plan to share these data at an upcoming medical meeting. So far, we have received timely responses from the FDA and are now utilizing our Fast Track Designation for additional discussions with the FDA regarding treatment refractory metastatic HPV positive squamous cell carcinoma of the head and neck. We believe our extended experience with Q2W dosing of Oz-V also has the potential to satisfy Project Optimus requirements, and we plan to share our results with the FDA to seek confirmation regarding our proposed recommended Phase III treatment regimen. Moving now to our CAB-CTLA-4 antibody, evalstotug. Partnering discussions are ongoing and we continue to believe that evalstotug has the potential to be best-in-class with a differentiated clinical profile relative to other CTLA-4 antibodies. To date, we have observed a 67% overall response rate and a 92% disease control rate in 12 evaluable patients with metastatic cutaneous melanoma. These results are notable given that 10 of 12 patients had received prior PD1 adjuvant or neo adjuvant treatment. We look forward to sharing additional data updates at a medical meeting later this year. With respect to our ongoing clinical communications, I am pleased to report our progress with the medical and scientific communities as acknowledged with ongoing abstract acceptances at prestigious conferences, including the American Society of Clinical Oncology, the American Association of Cancer Research and the Asthma Gastrointestinal Cancers Congress. Additionally, we are invited to give a presentation at the upcoming PEGS conference around our dual CAB EpCAM and CAB CD3 bispecific T cell engager. With that, I would now like to turn the call over to Rick to review the first quarter 2025 financials. Rick?

Thank you, Jay. Research and development or R&D expenses were $12.4 million for the quarter ended March 31, 2025, compared to $18.9 million for the same quarter in 2024. The decrease of $6.5 million was primarily due to lower clinical development expenses in 2025 for our Phase 2 trials for mecbotamab vedotin, ozuriftamab vedotin and evalstotug as we complete trials for certain indications. These decreases were partially offset by a $0.5 million charge related to our workforce reduction announced in March 2025. We expect our R&D expenses to continue to decrease for the remainder of 2025 due to our recent restructuring and as we complete Phase 2 trials for several indications and focus our ongoing development on our prioritized programs. General and administrative or G&A expenses were $5.3 million for the quarter ended March 31, 2025, compared to $5.6 million for the same quarter in 2024. The $0.3 million decrease was primarily due to lower stock-based compensation and lower D&O insurance premiums offset by a $100,000 charge related to our workforce reduction announced in March 2025. Net loss for the quarter ended March 31, 2025, was $15.3 million compared to a net loss of $23.2 million for the same quarter in 2024. Net cash used in operating activities for the quarter ended March 31, 2025, was $16.3 million compared to net cash used in operating activities of $30.8 million for the same period in 2024. Cash used for the quarter ended March 31, 2025 was $16.7 million. Cash and cash equivalents as of March 31, 2025, were $32.4 million compared to $49 million as of December 31, 2024. We expect that the significant cost reductions to be subsequently realized from our realignment of resources and focus on our two internal priority programs will provide the company with sufficient runway to fund operations and achieve key clinical readouts in the first half of 2026, excluding any funds from potential new partnerships. Now back to Jay.

Thank you, Rick. I'm encouraged with the progress across our CAB platform, particularly with our Phase 1 dose escalation study evaluating our dual conditionally binding EpCAM and CD3 bispecific T cell engager. I'm also encouraged with the maturing Phase 2 data sets, including the exceptional overall survival among patients treated with Mec-V as well as the compelling antitumor activity demonstrated with Oz-V and HPV positive head and neck cancer. These assets continue to be differentiated in some of the most challenging solid tumor types and have the potential to make a meaningful impact for patients suffering from these debilitating cancers. With that, we will turn it back to the operator to take your questions.

Thank you. We'll take our first question from Jeet Mukherjee with BTIG. Your line is open.

Great. Thanks for taking the question. I was wondering, will the poster presentation for the ROR2 program at ASCO contain an updated data cut? And for the EpCAM update in July, will we have data from the 300 microgram dose as well as the 900 microgram dose? Thanks.

Eric, why don't you answer the first question?

So the first question, are you inquiring about the Oz-V the ROR2-ADC asset? Yes. So we do have an updated data cut. We include any additional safety data from every other week dosing regimen of 1.8 mg/kg. And then we also will have some additional update on long term outcomes. And then you had a second question about EpCAM. And I think there, I would anticipate around the 25 to 30 patient update from our dose escalation data set, and that will occur mid this year.

And I don't think we have insight at the 900 microgram level at this point as we get closer. So it just depends on timing of patients.

Got it. Okay. And if I could just ask a follow-up, just any thoughts on a pivotal design for the AXL program and options for accelerated approval that might be there? Thanks.

Yes, we can talk a little bit about the AXL program. I think the key finding there is a remarkable overall survival. And I think that's nicely illustrated on Slide 26 of our corporate deck, where, with all the caveats, we're looking cross trial comparison. You can see that the now 8 patients with an extended overall survival of 18 months or more. And it's really a striking difference compared to the standard of care, which is docetaxel. So I think that the pivotal trial would likely be in second- and third-line patients with mutated KRAS non-small cell lung cancer randomized one to one against docetaxel. We've seen that approach employed by many sponsors, and we've received FDA guidance to that effect. They're supportive of that randomization.

I think from an accelerated approval standpoint, we think the ROR2 asset in head and neck cancer and second line plus probably does have that opportunity in HPV positive patients. So that's kind of exciting, and we certainly got some interesting discussions going on the potential partnering front because of that potential acceleration.

We'll move next to Reni Benjamin with Citizens JMP. Your line is open.

Hey, guys. Thanks for taking the questions. I guess also starting off with maybe the EpCAM program, can you provide some color regarding the types of tumor regressions that you're seeing? Jay, I think in your prepared remarks, you mentioned you're seeing tumor regressions as well as patients being on therapy for months. Can you give us a range maybe of how long these patients have been on therapy and any toxicities of note that have been seen to date? Then I have a follow-up.

This is great for Eric.

Yes. So I'm going to answer this question with an attention that midyear will be provided a more fulsome update in the medical congress. There have been two individuals, both with colorectal adenocarcinoma, that have had a remarkably extended progression free interval, one for more than a year and another for about 8 months and ongoing. We have three patients that have double-digit tumor reductions. But I want to be clear that we haven't yet observed a formal resist response. And the maximally tolerated dose has not been reached. We continue dose escalation. We anticipate that the biologically optimal dose might be 200 micrograms or more. And then you also asked about safety. And I've been pleased by what we're seeing to date. I think our stepwise dosing approach that's consistent with how other marketed T cell engagers are given is working. So I think that the safety issues are really non-concerning, and we continue to dose escalate. We have a lot of enthusiastic enrollers.

Great. And then just regarding Mec-V, I guess I'm kind of curious as to how we should be thinking about these landmark survival curves that you have and the readouts that you're reading, especially as it compares to not just maybe the standard of care, but also as you guys probably look at other drugs in development, the competitive landscape as it's kind of evolving. Could you maybe give us a sense as to how you're viewing this data in regards to that?

Well, I think it's very exciting. We're seeing the reason we're talking about landmark survival is because we haven't hit the median survival yet. We're still above the yeah. We're still above 50% and extending. So, I think, the cross-traffic impairment on slide 26 that really emphasized especially when you consider that our data have patients have three prior lines of therapy whereas the other comparators have they're in second line basically and were performing very well there. And I think in addition, I really while we're not while we're focused more on lung, I think the Sarcoma overall survival data was quite interesting. Here's another independent indication, different set of potential therapies downstream, and yet we're seeing pretty, and a really exceptional overall survival there, positive indications. And really this I'm just reminded everyone. This is where the drugs fail, especially in non-small cell lung cancer is in this overall surviving quadrant. And, this is great.

Yeah. Reni, maybe I'll just add a few points to that. Really looking at slide 26 and, the mutated KRAS non-small space is certainly changing with Revolution Medicine and others. But we also know that Sotorasib and their efforts to confirm clinical benefit were not successful. They had a non-evaluable trial for confirmation of clinical benefit. And really, overall survival is the bottom line here. We have to do that. So we have an antibody drug conjugate approach for these mutated KRAS patients that express AXL at a very high rate. And so I think it's interesting. Our approach is orthogonal to the new KRAS inhibitors that we're hearing about. I'm thrilled for patients that they have these options. But I think in the second line setting, our data are really standing quite strongly. And obviously they need to be confirmed in a prospective randomized trial.

Got it. Two other maybe just quick ones for me. One, you're talking about partnerships and discussions are ongoing. What does the ideal deal kind of look like for you guys? And number two, I think that you had mentioned that during the workforce cutting and trying to save your cash, you're going to focus on two internal programs. And I'm counting three, the EpCAM, and Oz-V. Can you just help clarify for me which are the two that you'll be focusing on moving forward?

The headcount reduction was implemented to align with the number of programs we are advancing internally. We are excited about ROR2, but we cannot pursue all four programs even though they are showing strong data. Initially, we selected two programs for partnering: ROR2 and CTLA4. This does not mean we are disregarding potential partnerships for Mec-V or the actual asset, and we are currently in discussions. We are focused on our internal programs versus external ones. Regarding the ideal partnership, I envision more than one, with at least one maintaining significant value in North America. The other should generate substantial cash value through upfront payments and near-term milestones. This combination will empower us to drive a Phase 3 either independently or with a partner. We are already having discussions that could lead to securing both types of partnerships. While we initially thought we could close two partnerships last year and ended up guiding one, we successfully closed the smaller of the two. We believe we are in a strong position to advance additional partnerships and are optimistic as we manage our cash runway to ensure we can make it into next year with some essential readouts and milestones along the way, potentially adding further opportunities.

Perfect. Thanks for taking the questions.

We'll move next to Arthur He with H.C. Wainwright. Your line is open.

Hey, good afternoon, Jay and T. Congrats on the progress. Just a couple of quick question on the EpCAM program. So we are looking at the middle year readouts from the dose escalation part. I'm sure we probably get the data from the 300 microgram cohort. So how about the D cohort with the 300 microgram? That's question one. And the question two is, when we had the readout for the dose escalation part, are you guys going to declare the expansion cohort dose level?

I would say we're I don't think we'll be declaring it at that point, but, we'll allow our data to teach us that, because I think so far I've encouraged where we're headed. And we're going to stick to this midyear, readout, no matter where we are in that dose escalation, we're willing to get some visibility to the data. But will there be added to this and also maybe comment on the d cohort as well? Sure.

And so Arthur, you had two questions, and we'll do everything we can to include data from the D cohort that you see listed on slide 19. We reopen that because we have such interest in the program from investigators and patients. And we wanted to also explore that two-step dosing regimen, as well as the one step. So we'll try to provide us fulsome of an update as we can at the Medical Congress. And you asked the question about would we declare the dose for the expansion cohort. I would imagine that we would. But at this time, we haven't defined that dose yet. And so as Jay said, I'll just echo, we're letting the data really teach us about this drug, where we want to take it next, how we want to deliver it and whether we want to stick to this weekly dosing regimen or move to every other dosing regimen, that's another possibility as well. So lots of optionality built into our protocol.

Got you. That's very helpful. And the another question is regarding the CRS control regimen. So could you tell us what's the regimen you guys are using to control the CRS in the study?

Sure. The approach that we're using is a pretty standard approach, and I want to emphasize the importance of step dosing, to give a relatively low dose and then subsequently a higher dose. We see that with marketed products, in particular, the marketed product for small cell lung cancer. The second is to really use industry standard approaches for CRS prevention. So patients are hospitalized. We follow them very closely. We do employ a tocilizumab prophylaxis strategy. And we really try to keep steroid use as modest as possible because steroids can affect T cell function as you know. And as you see on Slide 19, we've marched through the A, the B1, B2 all the way up through C1 up to C5 where we're dosing and then the D cohort as well. So, we continue to dose escalate. And I've been really pleased by what we're seeing and look forward to speaking to more data at an upcoming medical meeting.

Awesome. Thank you very much for the attention and color.

And it does appear that there are no further questions at this time. I would now like to turn it back to Jay Short for any additional or closing remarks.

Thank you for your attendance, and we look forward to communicating again very shortly again. So, take care.

Operator Closing Remarks.