BioAtla, Inc.

that can cause actual results to differ materially and are described in the filings made with the SEC, including the most recent quarterly report on Form 10-Q. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of today, May 11, 2023, 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 first quarter 2023 BioAtlas earnings call. Before I provide an update on our first quarter progress, I would like to reiterate a few key points made on our last quarter call in March. As a reminder, BioAtlas is the inventor and leader in the development of novel therapies using a proprietary conditionally active biologics CABs platform with improved selectivity for attacking tumor cells while avoiding healthy cells to address urgent unmet needs in oncology in order to improve patients' lives. We made significant progress last year across our multiple ongoing phase two trials for our two latest stage first-in-class CAB-ADC product candidates, BA3011 and BA3021, targeting solid tumor types with high unmet medical needs. As we are now a little over one full quarter into 2023, we continue our positive trajectory and are on track to achieve our recently guided milestones. We remain focused on further advancing the development of our innovative clinical programs, leveraging the broad applicability of our CAB technology across several clinical stage antibody types, including CAB-AXL and CAB-WAR2 ADCs, targeted CAB-CTLA-4, an immuno-oncology naked antibody, and our first dual-cap bispecific EPCAM CD3 T-cell engager. Additional details related to what I'm going to provide are available on our website as part of our updated company presentation that may be helpful to you. We have shared promising clinical responses to date that are so far meeting and in several cases exceeding our interim study targeted responses. Last quarter, I shared our strategic shift from providing incremental data updates on small sample sizes to releasing more mature data sets across our programs. As a reminder, our goal is to provide sufficient data to allow us to set study parameters that maximize the company's likelihood of success for our Phase II potentially registrational studies. Additionally, last quarter I discussed the rationale for including the more frequent dose-intensive regimens. A summary of these current dose regimens can be found in our updated corporate presentation on our website. Based on our exposure response analyses, as well as our UPS-related FDA interactions, we aim to maximize the differentiated benefit-risk profile of our CAB ADCs in our Phase II Part I trials for potential further improvement in antitumor activity while having similar or even improved safety profiles. We continue to be excited about our lead asset, BA3011, for multiple indications. Previously, we shared the encouraging partial interim data on our BA3011 Phase 2 Part 1 sarcoma study and our BA3011 Phase 2 Part 1 non-small cell lung cancer study. Let's now move to our clinical, operational, and financial updates for the first quarter of 2023. First, I will reiterate our BA3011 phase 2 sarcoma study and our overall sarcoma strategy. We are advancing BA3011 in ongoing sarcoma phase 2 studies, including a potentially registrational study in UPS. As a recap of the unmet need in UPS, it is one of the largest and most aggressive sarcoma subtypes with high reoccurrence rates, representing nearly 15% of all soft tissue sarcomas. Without specific treatments approved for UPS, there is a significant commercial opportunity as a standalone indication. We have shown strong execution and promising results with continued anti-tumor activity, lack of disease progression, and a differentiated safety profile of BA3011 in UPS to date. Additionally, we have observed an overall objective response rate, or ORR, of 50%. medium progression, free survival, or PFS of over 11 months, and a duration of response exceeding eight months. Based on these results, together with the continued differentiated safety profile and encouraging feedback from the FDA around the study design, last year we initiated part two of the potentially registrational portion of the trial. The first 40 patients with a TMPS greater than or equal to 50% are being randomized one-to-one between the 3Q4W or 2Q3W dosing regimens. Following this, we plan to enroll an additional 40 patients at the selected dose to complete the study. Overall, the primary efficacy endpoint ORR will be based on approximately 60 patients treated at the selected dosing regimen. UPS represents a solid early indication for BioAtla as we plan for the transition into a commercial stage company. In addition to UPS, we continue to enroll in the Lyomyosarcoma cohort using the 3Q4W dosing regimen and are on track with anticipated data readout in the second half of this year. With regards to the safety profile across sarcoma subtypes, BA3011 continues to be generally well tolerated with a Phase II safety profile across all doses consistent with the profile we observed in Phase I. We also see real value in potentially expanding our sarcoma footprint over time to include other sarcoma subtypes. Ultimately, we believe VA3011 has the potential to treat over 25,000 sarcoma patients per year and generate up to $2 billion in revenue worldwide in this area of high unmet need. Regarding our VA3011 Phase II study in axopositive multi-refractory non-small cell lung cancer, we continue to be enthusiastic about the data we presented earlier this year with the Q2W dosing regimen. Currently, the competitive landscape is scant for treatment options in patients who progress on immune checkpoint inhibitors, particularly in the second line and beyond settings. These patients have suboptimal overall ORRs of approximately 10% to 20% and PFS rates of four months. As a reminder, part one of a phase two study in non-small cell lung cancer is ongoing in axial positive patients who have previously experienced failure of either PD-1, PD-L1, EGFR, or ALK inhibitors. So far in the study, we have reported preliminary efficacy with an ORR of 44% as monotherapy in a PD-1 failure population that have seen, on average, three prior lines of therapy. This response rate is highly competitive and exceeded our targeted response for moving forward to the Phase II potentially registrational part of the study. We continue to believe BA3011 will be highly commercially relevant with a response well above those observed in a multi-refractory patient population, particularly in view of treating patients in earlier lines in Phase 2, Part 2. In addition, Part 1 of the Phase 2 study continues to enroll using the more frequent dose-intensive regimen with anticipated data readout for all dosing regimens on track for the second half of this year. We remain on track to submit a meeting request to the FDA for the potentially registrational BA3011 Phase II Part II non-small cell lung cancer study design in the first half of this year, with feedback anticipated in the second half of this year, allowing us to initiate the Phase II Part II study in non-small cell lung cancer in the second half of this year, maintaining our overall timeline for development of the non-small cell lung cancer indications. As we have previously mentioned, approximately 35% of patients in this second line plus indication of non-small cell lung cancer express axel. We estimate annually that there are over 100,000 axel-positive addressable patients worldwide with the potential to add approximately $2.5 billion to $3 billion in worldwide revenue at peak. Considering only the sarcoma non-small cell lung cancer indications, we continue to believe that BA3011 has the potential to become a significant commercial asset for Biolatla. Of even greater importance is that BA3011 has the potential to be the best-in-class treatment for a significant number of patients who fail multiple lines of therapy, thus filling a significant unmet medical need. To round out our CAB ADC BA3011 program, we are supporting an ongoing multicenter investigator-initiated or IIT Phase II clinical trial in patients with platinum-resistant ovarian cancer. The trial is on track, and we anticipate interim data consisting of 10 patients in the second half of this year. Now turning to our second lead CAB ADC product candidate, BA3021, a CAB or two ADC. Currently, BA3021 is the subject of Phase II trials and the treatment of four indications. As a reminder, no other company has a therapy in the clinic targeting ROR2, so we have the potential to have a first-in-class treatment for solid tumors. We conducted a similar exposure response analysis of ROR2-positive tumors to inform the more frequent dose-intensity regimen in our Phase II ROR2-positive non-small-cell lung cancer study. Based on this analysis, which utilizes a similar strategy to our UPS Phase 2 Part 2 BA3011 study I mentioned earlier, we are continuing to enroll patients in the more frequent dose-intensity regimen of 3Q4W as planned with interim data readout on track for the second half of this year. Regarding the melanoma Phase 2 trial in patients who have previously experienced failure of PD-1 therapy, Following an additional complete response in an evaluable patient identified using our IHC assay, we are screening patients with the validated liquid biopsy. Although we haven't enrolled additional patients to date, we have successfully identified more two positive tumors using the liquid biopsy assay, which is now allowing us to enroll more two positive patients. We anticipate an increased enrollment in the second half of this year. In addition, our Phase II head and neck study is ongoing in patients who have previously experienced failure of PD-1 therapy alone or in combination with Platinum therapy. Last quarter, we announced achievement of first patient in for this study. Since last quarter, we continue to enroll patients and the observed ROR2 positivity rate is high, over 50%, and in line with our expectations. To round out our CAB ADC BA3021 program, We are also supporting the Phase II IIT study with BA3021 in patients with platinum-resistant ovarian cancer. The trial is on track and we anticipate interim data consisting of 10 patients in the second half of this year. Now I'd like to talk briefly about our Phase I-II trial for our CAB CTLA-4 antibody, BA3071. As a reminder, the Phase I-II trial is being conducted in tumors known to be responsive to CTLA-4 treatment, and we will evaluate safety and tolerability of BA3071 in monotherapy and in combination with nivolumab. The trial is progressing as planned. Last quarter, I shared that the DLT observation period was cleared for the fourth cohort at a dose of 210 mg, or 3 mg per kg, in combination with 3 mg per kg of nivolumab. No DLTs were reported. As part of today's update, we are treating patients in the fifth cohort at 350 mg or 5 mg per kg as a monotherapy or in combination with 3 mg per kg of nivolumab and are on track for a Phase I beta readout in the second half of this year. We also remain on track for the initiation of our BA303 Phase 2 study to commence in the second half of this year. Finally, on to our potentially first-in-class dual-CAB bispecific T-cell engager antibody, CAB-FCAM-CAB-CD3, or BA3182. In the first quarter, we received FDA clearance of our IND for the treatment of advanced adenocarcinoma. We anticipate first patient in for the phase one study in the current quarter with the complete phase one data readout anticipated next year. Similar to our other three clinical stage CAB product candidates, this antibody holds much promise in view of the in vivo preclinical studies demonstrating an over 100-fold improvement in the therapeutic index relative to the non-CAB variants due to the combined selectivity of the dual CAB design. Several of the most common subtypes of adenocarcinoma that have tremendous unmet need that we can potentially address include colon, lung, breast, pancreas, and prostate. BioATLA also continues to progress several candidates through IMD-enabling studies, including CAB-by specifics and next-generation ADC antibodies. And we still anticipate IMD submissions for additional candidates potentially in 2023 and through 2024. With respect to important ongoing communications, the company has nine accepted recent and upcoming poster presentations since March, including at the Asthma Sarcoma and Rare Cancers Congress, the European Lung Cancer Congress, AACR, and ASCO, the latter of which will include an online publication of the abstract related to exposure response analyses of BA3011. Additional asterisks have been submitted for several upcoming meetings, and these will be updated as they are accepted. With that, I would now like to turn the call over to Rick to review the first quarter of 2023 financials. Rick? Thank you, Jay.

As of March 31, 2023, we had $192.7 million in cash and cash equivalents compared to $215.5 million as of December 31, 2022. We expect current cash and cash equivalents will be sufficient to fund planned operations including all ongoing CAB product development programs into 2025. As a reminder, we control all CAB product market rights in the U.S., Europe, and Japan. Our business strategy includes advancing commercial preparations in key global markets while exploring opportunities to extend our cash runway by generating upfront cash through the selective licensing of product rights in certain territories or collaborations with other biopharmaceutical companies that could also provide to us development milestones and royalties upon regulatory approval and commercialization. and create additional value for stockholders. For the first quarter ended March 31, 2023, we reported a net loss of $27.5 million compared to a net loss of $24.3 million in the same period of 2022. Research and development expenses were $21.7 million for the first quarter ended March 31, 2023, compared to $16.9 million for the same period in 2022. The increase of $4.8 million was primarily driven by our preclinical and clinical product development efforts. We expect our R&D expenses to remain variable from quarter to quarter and generally increase as we continue to invest in R&D activities to advance our product candidates and our clinical programs. General and administrative expenses were $7.2 million for the first quarter ended March 31, 2023, compared to $7.4 million for the same period in 2022. The $0.2 million change was attributable to a decrease in various expenses for the 2023 period. We expect our G&A expenses to moderately increase to support development of our product candidates, advance our intellectual property portfolio, support focused pre-commercialization activities for our product candidate BA3011, and satisfy requirements as a public company. Net cash used in operating activities for the three months ended March 31, 2023 was $22.7 million compared to net cash used in operating activities of $25.1 million for the same period in 2022. The decrease in net cash used in operating activities for the first three months of 2023 is primarily due to an increase in accounts payable and accrued expenses in the 2023 period compared to a decrease in accounts payable in the same period in 2022. And now, back to Jay.