CytomX Therapeutics, Inc.

Good afternoon, everyone. Thank you for standing by. Welcome to the Cytomics Therapeutics first quarter 2026 financial results call. Please be advised that today's conference is being recorded. I would now like to hand the call over to your host for today, Chris Ogden, Cytomics Chief Financial Officer. Please go ahead.

Thank you. Good afternoon, and thank you for joining us. Before we begin, I would like to remind everyone that during this call, we will be making four looking statements. Because forward-looking statements relate to the future, they're subject to inherent uncertainties and risks that are difficult to predict, and many of which are outside of our control. Important risks and uncertainties are set forth in our most recent public filings with the SEC at sec.gov. We undertake no obligation to update any forward-looking statements, whether as a result of new information, future developments, or otherwise. Earlier this afternoon, we issued a press release that includes a summary of our first quarter, 2026, financial results, and highlights recent progress at Cytomix. We encourage everyone to read today's press release and the associated materials, which have been filed with the SEC. Additionally, the press release, recording of this call, and our SEC filings can be found under the investors and news section of our website. With me on the call today is Dr. Sean McCarthy, Citomix's Chief Executive Officer and Chairman. Sean will provide an update on our pipeline and company progress before I cover the financials for the quarter. We will then conclude with a Q&A session. With that, I'm going to turn the call over to Sean.

Thanks, Chris, and good afternoon, everyone. We're very pleased to be here today to provide an update on our first quarter developments and guidance for what's continuing to be a transformational year for cytomics. 2026 is also a very exciting start, driven by our excellent clinical progress with Varsetta-M in late-line colorectal cancer. Varsetta-M is a first-in-class EPCAM-targeting antibody drug conjugate, or ADC, that was uniquely designed and enabled by our proprietary pro-body therapeutic masking platform. Varsetta-M is the only EPCAM-directed ADC in clinical development, to our knowledge, affording us a strong lead and a powerful competitive advantage. EPCAM is one of the most abundant solid tumor surface antigens, and Cytomix's breakthrough in unlocking EPCAM as an ADC target positions Varsetta M as a company building asset over the near and long term. We see multiple layers of value creation potential for Cytomix through the advancement of Varsetta M. In colorectal cancer, which I'll now refer to as CRC, our goal is for Varsetta to become a core component of the standard of care, including in early aligned therapy. Metastatic CRC remains one of the largest areas of unmet need in oncology today, which really underscores the urgency we feel at Cytomix to progress Varsetta M towards the market as rapidly as possible. Commercially, in the late line setting alone, this represents a multi-billion dollar market. In addition to the very substantial opportunity in CRC, we also plan to capitalize on our leadership in EPCAM targeting by developing Varsetta M in other cancers and ultimately as a pan-tumor therapy. Varsetta has the long-term potential to positively impact the lives of so many people with cancer, and we are focused on executing with urgency to rapidly progress this potential therapy to regulatory approval. Cytomix has made a very strong start in the clinic with Varsetta M. In our most recent phase one data update in March this year, we shared updated efficacy data in late line metastatic CRC showing a confirmed overall response rate between 20 and 32% and approximately seven months of median progression-free survival. These data position Varsetta as a potentially transformative step forward in the treatment of metastatic CRC, where currently available therapies offer overall response rates only in the low single digits and just a few months of PFS. Varsetta M is working exactly as designed, and it's unlocking the true potential of Epcam for the first time. With Varsetta, Cytomix is bringing the power of the ADC class to colorectal cancer. I want to really underscore here that we've achieved something very significant with our ProBody platform technology. In our view, and based on our preclinical data and efforts of others over many years, we believe we can say with confidence that a conventional, unmasked ADC targeting Epcam would have no chance of achieving dose levels that deliver meaningful anti-cancer activity due to severe on-target toxicities. In contrast with Varsetta M, we have achieved remarkable anti-cancer activity in one of the hardest to treat cancer types. We firmly believe we have done the hardest experiment first by focusing initially in CRC and that the best is yet to come. In terms of key near-term objectives for Varsetta M, we are currently in dose optimization with the goal of advancing into a registrational study in late-line CRC in the first half of 2027. Today we're very pleased to share that we have completed enrollment in the ongoing dose optimization cohorts with 40 total patients now enrolled across the 8.6 and 10 milligram per kilogram doses, taking total enrollment across the phase one study to 113 patients. We remain well on track for an update before the end of this year as we work towards prioritizing one of these two doses of this highly active drug candidate for our first pivotal study. In evaluating the potential registrational study dose, we're focused on optimizing the risk benefit of Varsetta M, building on the significant learnings in the dose escalation, expansion, and optimization phases. Regarding Varsetta M safety, we have been highly encouraged by the preliminary results we shared in March from dose optimization that show that updated patient management strategies have the potential to substantially reduce the rate of high-grade diarrhea we saw earlier in Phase I development. This is the principal adverse event of interest with Varsetta, and it's something we feel confident we can get an increasingly well-developed understanding of as we move forward through the optimization cohorts and beyond. Typically, patients respond very well to management, And our overall discontinuation rates are low, accounting for the impressive progression pre-survival data we have shared to date. In terms of our next clinical communication, we expect to provide an overall phase one data update, including safety and efficacy from the monotherapy dose optimization in the second half of this year. We expect these data, along with FDA interactions in 2026, to inform Varsetta-M monotherapy dose selection and the first registrational study design. Our primary goal with Varsetta M is initially to develop in the late line where we see this drug candidate as highly differentiated and, frankly, as offering a highly impactful new option for CRC patients. Over time, our vision for Varsetta in CRC is to replace systemic Irinotecan in the treatment paradigm and potentially to displace chemotherapy entirely. Accordingly, and in parallel to its development as a monotherapy in CRC, we are aggressively advancing Varsetta M into combination studies to enable earlier line utilization. Strategically, we see an enormous opportunity for Varsetta in early line CRC. To access this opportunity, we have initiated a combination with Bevacizumab as a first step to moving Varsetta into earlier line therapy. Anti-VEGF antibodies, including bevacizumab, are extensively utilized in early and late-line CRC treatment, so this will be a foundational combination. Parsetta M doses assessed in combination with bevacizumab will include both every two weeks and every four weeks schedules to align dosing with the approved five mg per kg every two weeks schedule, standardly used in the clinic today. We expect initial clinical data for this combination by the first half of 2027. We're also accelerating plans to study Varsetta in combination with chemotherapy, and we plan to begin a Phase I-II chemotherapy combination study in the second half of 2026, evaluating Varsetta in combination with Bevacizumab, bifluorouracil, and leucovorin with the potential to advance into the first and second lines. In addition to our work in colorectal cancer, we are on track to begin phase one expansion cohorts in additional EPCAM expressing indications in the second half of 2026. We look forward to providing an update on the initial non-CRC indications later this year with the goal of generating clinical data supporting Varsetta's ultimate pan-tumor potential. Turning now to CX801. our masked interferon alpha 2B program, which is currently in phase one development for advanced checkpoint refractory melanoma. Our vision here is for CX801 to become a new centerpiece for combination cancer immunotherapy as we harness and redirect the power of this cytokine to reprogram and activate anti-tumor immunity. We initially see CX801 as well-positioned to address the higher need in PD-1 refractory melanoma, where response rates to approved standard of care remain in the single-digit percentages with limited treatment options available or in clinical development. Interferon alpha-2b is a potent cytokine that has validated clinical activity in melanoma and other cancers, And our initial translational data from phase one suggests that CX801's mechanism of action is working as designed in the tumor microenvironment. Importantly, our data shared at CITC in 2025 are highly supportive of our strategy for combining with the checkpoint inhibitor Keytruda. Our ongoing CS801 phase 1 monotherapy dose escalation study has advanced to the fourth dose level, which exceeds the approved clinical dose of unmasked interferon alpha 2B. CS801 has been well tolerated to date, suggesting that our masking strategy is broadening the therapeutic window as designed. Combination dose escalation with Keytruda is also progressing very well and is now actively enrolling in the third dose level. Overall, we view CX801 as very well positioned to address a significant unmet need in advanced melanoma, and we look forward to sharing initial clinical data by the end of this year. With that, I'll now transition back to Chris.