BioAtla, Inc.

Greetings and welcome to the BioATLA fourth quarter and full year 2023 earnings call. At this time, all participants are in a listen-only mode. A brief 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. As a reminder, this conference is being recorded. It's now my pleasure to introduce your host, Bruce Mackel with LifeSci Advisors. Thank you, Mr. Mackle. You may begin.

Thank you, Operator, and good afternoon, everyone. With me today on the phone from BioAtla are Dr. Jay Short, Chairman, CEO, and Co-Founder, and Richard Waldron, Chief Financial Officer. Following today's call, Dr. Eric Sievers, Chief Medical Officer, and Sherry Leidig, Chief Commercial Officer, will join Jay and Rick for a short Q&A. Earlier this afternoon, BioAtla released financial results and a business update for the fourth quarter and full year ended December 31, 2023. 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 BioAtlas 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, 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, March 26, 2024, 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 Jay Short. Jay?

Thank you, Bruce, and thanks to everyone for joining us for our fourth quarter full year 2023 BioAtla earnings call. BioAtma is the inventor and leader in the development of novel therapies using a proprietary, conditionally active biologics or CABs platform with improved selectivity for attacking tumor cells while avoiding healthy cells, thereby addressing critical and met needs in oncology to improve patients' lives. We made considerable progress in 2023 across all of our ongoing clinical programs, including the Phase II trials for our first-in-class CAB, ADC, product candidates BA3011 and BA3021, targeting multiple solid tumor types. Our CAB C24 IO antibody and our first dual-CAB bispecific EPCAM CD3 T-cell engager. We continue the positive trajectory into 2024, focused on further advancing our prioritized CAB programs generating datasets that potentially enable us to move into one or more registrational trials in the second half of the year. We believe that these near-term inflection points also support the formation of one or more strategic collaborations with major pharmaceutical partners this year, which can accelerate the development of selected assets and maximize their market opportunities. Additional details related to what I'm going to provide are available in today's press release and our updated company presentation, both of which are available on our website. I will now review our latest updates, beginning with our CAB-CTLA-4 antibody, DA-3071, which is applicable in areas of high unmet need across multiple solid tumor indications, both for refractory and for first-line patients, and represents a sizable commercial opportunity. We are pleased to report that our phase two data at 350 milligrams flat dose continues to mirror our phase one dose escalation data in terms of low incidence and severity of immune-related adverse events. In addition, I'm happy to report that we have cleared a higher dose of 700 milligrams with tocilizumab for the first two cycles and are now evaluating the unprecedented one gram dose level. This is important since previous studies demonstrated improved overall survival in metastatic cancers including melanoma with higher levels of CTLA-4 inhibition. As a result, we are now enrolling patients at 700 milligrams in first-line melanoma patients and in a significant targeted first-line non-small cell lung cancer population in combination with PD-1 for readouts later this year. These data are also anticipated to position the company for one or more potentially registrational trials and first-line indications in the second half of this year. In addition, as part of our evaluation of safety and tolerability of BA3071, we are completing the Phase II expansion in treatment refractory melanoma and carcinoma with an initial data readout of approximately 20 patients in second quarter. As already noted, the safety and efficacy data from the phase one study demonstrating both a confirmed partial response and a confirmed complete response for two out of six patients is encouraging using the 350 milligram dose. And now we are enrolling the remaining patients at the 700 milligram dose. With our evolving clinical data, we believe DA3071 has the potential to be best-in-class CTLA-4 that holds the promise to be used as often as a PD-1 inhibitor, and potentially expand the indications where combined immune checkpoint inhibition can be effective. In addition, the emerging safety profile suggests that BA3071 with PD-1 immune modulation may be suitable for further combining with CAB ADC therapies that target Axel and or War II to achieve synergistic durable tumor control. Now turning to our CAB War II ADC asset, BA3021. For our ongoing Phase II trials in treatment refractory Ward II agnostic patient populations, we previously reported encouraging responses in the Phase II melanoma and squamous cell carcinoma, the head and neck studies. As part of today's update, we now have both 28 melanoma patients and 12 head and neck patients dosed using the 1.8 milligram per kilogram Q2W regimen. and 20 head and neck patients dosed using the more intense 2Q3W regimen for a total of 32 head and neck patients. We anticipate having two plus scans in the melanoma cohort next month and two plus scans in the head and neck cohort in May, with anticipated top-line data readouts for both during our Q1 earnings call in May. Given the encouraging emerging data sets, we believe BA3021 is well-positioned for a global strategic collaboration to maximize the potential of this CAB-ADC across multiple solid tumor indications. On to our CAB-AXL-ADC BA3011. Our Phase II Potentially Registrational Study for Undifferentiated Pneumorphic Sarcoma, or UPS, is on track to complete enrollment of approximately 20 actual agnostic patients at the 1.8 mg per kg 2q3w regimen next month with encouraging compliance and manageable safety. We anticipate having multiple scans across the patient group potentially enabling a meeting with the FDA to discuss the remaining portion of the potentially registrational study in the second half of this year. We also reported clinically meaningful anti-tumor activity among patients with treatment refractory bone and soft tissue sarcomas, which remain a profound and tractable unmet need for new treatment options. We presented these data from Phase II Part I cohort enrollment as an oral presentation at the Asthma, Sarcoma, and Rare Cancers meeting earlier this month and showed disease control at 12 weeks for 43% of the 87 patients treated with BA3011. monotherapy using the less intense regimen of 1.8 mg per kg Q2W. We believe this represents a promising disease control rate for patients with treatment refractory sarcomas. In the osteosarcoma cohort, we observed two partial responses out of 11 efficacy-available patients. The treatment was well-tolerated and associated with a manageable safety profile with no new safety signals to report. Now regarding our phase two study in non-small cell lung cancer, last quarter we reported multiple durable clinical responses with a differentiated safety profile among a challenging axopositive treatment refractory lung cancer population. Specifically among 15 patients with EGFR wild type tumors who had received prior PD-1 treatment, we observed five partial responses with a medium duration of response of approximately five months using 1.8 milligrams per kilogram, Q2W, every other week dosing. Toxicity was manageable, and few high-grade related treatment emergent AEs were reported. We believe multiple responses in a treatment refractory, axial positive, poor prognostic group such as this one is clinically meaningful and relevant, particularly since these patients have experienced failure of a median of three prior lines of therapy. As part of today's update, we have enrolled 33 target agnostic patients using the more intense 1.8 mg per kg 2Q3W regimen across both squamous and non-squamous patients. We are on track to evaluate clinical benefit in the target agnostic non-small cell lung cancer non-squamous population in the second quarter of this year. Next, onto our potentially first-in-class dual-CAB bispecific T-cell engager antibody, CAB-EPCAM, CAB-CD3, or DA3182. EPCAM is a ubiquitous target expressed from the surface of cancer cells, which requires the use of our CAB technology to achieve optimal selectivity and safety. Our Phase I-II dose escalation study continues to progress and is on track. We anticipate completion of the Phase 1 study with a full data readout anticipated in the second half of this year, with potential initiation of a Phase 2 study also in the second half of this year. If shown to be safe and effective among cancer patients enrolled, our CAB-enabled T-cell engager has the potential to treat patients with a wide range of metastatic tumors, including cancers of colon, lung, breast, pancreas, and prostate, among others. As we have previously discussed, ADCs are a promising treatment modality with broad applicability across multiple tumor types. To further reduce the potential risk associated with neutropenia from off-target toxicity, we developed a novel next-gen carbohydrate linker system with superior serum stability, solubility, and tumor-specific payload release, yielding our first glycoconjugate CAD-Nectin-4 ADC, BA-3361. At the upcoming AACR meeting in April, efficacy data will be presented demonstrating complete tumor regression in xenograft models, including superior efficacy compared to infortimab, the dotin analog, and the patient-derived pancreatic cancer model. We will also present both PK and toxicology data in non-human primates, as well as the influence of our linker technology in specific cancer models. These data indicate that our next-gen CAB Nectin-4 ADC petition is a more effective treatment with reduced toxicity. We plan to submit the IND in April. And finally, I'm pleased to report our progress with the medical and scientific communities and important ongoing communications with numerous publications and presentations, including at conferences such as Asthma, Sarcoma, and Rare Cancers, SITC Spring, and the AACR Annual Meeting in April, which can be found on our website. With that, I would now like to turn the call over to Rick to review the fourth quarter and full year 2023 financials. Rick?