CytomX Therapeutics Q2 2026 Earnings Report

CytomX Therapeutics EPS Results

• Actual EPS: -$0.09
• Consensus EPS: -$0.08
• Beat/Miss: Missed by -$0.01
• One Year Ago EPS: N/A

CytomX Therapeutics Revenue Results

• Actual Revenue: $1.42 million
• Expected Revenue: $12.39 million
• Beat/Miss: Missed by -$10.97 million
• YoY Revenue Growth: N/A

CytomX Therapeutics Announcement Details

• Quarter: Q2 2026
• Date: 8/6/2026
• Time: After Market Closes
• Conference Call Date: Thursday, August 6, 2026
• Conference Call Time: 5:00PM ET

CytomX Therapeutics (NASDAQ:CTMX) (NASDAQ: CTMX) is a clinical-stage biopharmaceutical company focused on developing cancer therapies designed to selectively activate in the tumor microenvironment. The company’s Probody therapeutic platform uses molecular masking technology intended to limit antibody activity in healthy tissue and enable activation by proteases that are more prevalent in tumors.

CytomX’s pipeline includes investigational therapies spanning several modalities, including Probody drug conjugates, T-cell engagers and cytokine-based treatments. Its programs have included CX-2051, a CEACAM5-directed Probody drug conjugate; CX-904, a conditionally active T-cell engager targeting EGFR; and CX-801, an investigational tumor-targeted interferon-based therapy. These candidates are being studied for potential use in solid tumors, although the company does not currently market an approved product.

Founded in 2008 and headquartered in South San Francisco, California, CytomX has advanced its programs through internal research and collaborations with pharmaceutical companies, including Astellas Pharma and Bristol Myers Squibb. The company’s therapies are intended for development and potential commercialization in international oncology markets, subject to clinical and regulatory approval. CytomX has been led by President and Chief Executive Officer Sean McCarthy, Ph.D., a co-founder of the company.

CytomX Therapeutics Q2 2026 Earnings Call Transcript

Key Takeaways

• Positive Sentiment: Varseta-M dose-optimization enrollment is complete, with a 113-patient Phase I study ongoing; CytomX expects to report broader monotherapy data, including initial progression-free and overall-survival information, by year-end 2026 and start a potential registrational study in the first half of 2027.
• Positive Sentiment: The company is expanding Varseta-M into earlier-line colorectal cancer through bevacizumab and 5-FU/leucovorin combinations, with initial combination data expected in the first half of 2027 and a goal of replacing irinotecan in second-line treatment.
• Positive Sentiment: CytomX is broadening Varseta-M into gastric/GEJ, pancreatic, and biliary tract cancers through new Phase I expansion cohorts, potentially positioning the drug as a pan-gastrointestinal ADC.
• Positive Sentiment: CytomX received a $37 million Regeneron payment in July for two additional collaboration targets, taking pro forma cash to approximately $367 million; management projects cash runway into at least the second half of 2028.
• Negative Sentiment: Diarrhea remains a key development risk for Varseta-M, particularly if Grade 3 rates trend toward the high end of the company’s 10%–20% risk-benefit range, which could affect its movement into earlier treatment lines despite reported improvement with loperamide and budesonide prophylaxis.

Presentation

[Operator]

Good afternoon, everyone. Thank you for standing by. Welcome to the CytomX Therapeutics Second Quarter 2026 Financial Results Call. Please be advised that today's call is being recorded. I would now like to hand the call over to your host for today, Chris Ogden, CytomX Chief Financial Officer. Please go ahead.

[Chris Ogden, CFO at CytomX Therapeutics]

Thank you. Good afternoon. Thank you for joining us. Before we begin, I would like to remind everyone that during this call, we'll be making forward-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.

[Chris Ogden, CFO at CytomX Therapeutics]

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.

[Chris Ogden, CFO at CytomX Therapeutics]

Earlier this afternoon, we issued a press release that includes a summary of our second quarter 2026 financial results and highlights recent progress at CytomX. We encourage everyone to read today's press release and the associated materials which have been filed with the SEC.

[Chris Ogden, CFO at CytomX Therapeutics]

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, CytomX'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'll turn the call over to Sean.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Thanks, Chris. Good afternoon, everyone. We're pleased to be here today to provide an update on our second quarter developments and what continues to be a highly productive year for CytomX. Our major focus continues to be Varseta-M, our first-in-class EpCAM targeting antibody drug conjugate, which to our knowledge is the only EpCAM-directed ADC in clinical development.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We are aggressively developing Varseta-M in metastatic colorectal cancer, which I will refer to as CRC. The unmet need in CRC is very high and, in fact, projected to grow due to increased incidence in younger patients on a global basis. We view Varseta-M as a highly innovative drug candidate for the treatment of CRC and potentially the best-in-class ADC based on our clinical data reported to date.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

The Varseta-M development program is broadening rapidly, and we see significant value creation potential across our key priorities, which include, first, advancing Varseta-M toward a registrational study and potential approval as a monotherapy in late-line CRC. Second, developing Varseta-M in combinations to expand into earlier-line CRC with the vision to ultimately replace chemotherapy.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Third, exploring Varseta-M as a pan-tumor therapy across multiple EpCAM-expressing cancers. In terms of our operational progress this quarter, I'll start with Varseta-M monotherapy development in late-line CRC. We have enrolled 113 patients into the overall Varseta-M phase I monotherapy study across dose escalation, expansion, and optimization.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Enrollment in dose optimization was completed in April, with a total of 40 patients enrolled across the 8.6 and 10 mg per kg doses utilizing adjusted ideal body weight dosing.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We remain on track to report by the end of 2026 a phase I data update for Varseta-M across the entire ongoing phase I trial, with a key focus on the data that underpins monotherapy dose selection and the go-forward development strategy for our first registrational study that we aim to initiate in the first half of 2027. We continue to see monotherapy registrational strategies in either the third or fourth line, depending upon emerging data, as compelling opportunities.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We look forward to communicating our strategy later this year. In addition to monotherapy development, we are aggressively advancing Varseta-M in combinations to enable earlier-line CRC therapy. We have made significant progress this quarter. The first combination we're exploring in an ongoing phase I cohort is with bevacizumab, a foundational component of current standard of care in CRC across early and late lines of treatment.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We are exploring Q2-week and Q4-week schedules to align with the clinical schedule of bevacizumab. We continue to enroll late-line patients. We expect to focus on earlier-line patients once we have selected a go-forward dose and schedule. We anticipate reporting initial clinical data in the first half of 2027.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Our second combination study that we plan to initiate in Q4 will be a new phase I/II trial initially evaluating escalating doses of Varseta-M in combination with bevacizumab, 5-fluorouracil, and leucovorin in 2nd-line CRC patients.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

This study is central to our goal of replacing irinotecan with Varseta-M in earlier-line CRC. I'd like to emphasize here that our work to date with Varseta-M has been conducted entirely in late-line unselected CRC patients.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We've made terrific progress. We view Varseta-M as a treatment for all patients with late-line CRC, including patients with liver mets, KRAS mutations, and other clinically meaningful characteristics that in other settings are used to differentiate patients and their treatment options. We think this pan-CRC potential makes Varseta-M stand out from other treatment options.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We look forward to building on our promising start by bringing Varseta-M forward as a potential frontline treatment option, ultimately replacing chemotherapy. Now, moving to the development of Varseta-M outside of CRC. We're very excited today to announce that we are initiating phase I expansion cohorts in additional gastrointestinal cancers.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Initially, we are expanding into gastric and gastroesophageal junction cancer, pancreatic ductal adenocarcinoma, and biliary tract cancer. These are all EpCAM-positive tumor types. In each case, we see significant unmet need that Varseta-M could potentially address.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We prioritize these tumor types based on a number of criteria, including their known responsiveness to topoisomerase I inhibition and our own Varseta-M preclinical data. We believe these indications could offer compelling regulatory opportunities. Our initial plan is to enroll approximately 20 patients per tumor type to assess Varseta-M's antitumor activity and safety before assessing next steps and potential later-phase development options.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

As a reminder, in colorectal cancer, we are enrolling an unselected patient population due to the uniformly high expression of EpCAM in this cancer type. For our newly selected GI expansion indications, we think patient selection is advisable in certain cases in order to enrich the patient population while we continue to learn about the relationship between target level and antitumor activity. For pancreatic and biliary tract cancer, we expect to screen patients for EpCAM expression.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

For gastric and gastroesophageal junction cancer, like CRC, we expect to enroll an unselected patient population given the high percentage of patients expected to have EpCAM-expressing tumors. Overall, we believe the successful execution of these expansion cohorts could further position Varseta-M as a pan GI ADC, providing additional development opportunities across multiple lines of therapy.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

To summarize, we are very pleased with the continued progress with Varseta-M, as this really exciting program deepens and broadens toward our first registrational study to earlier lines of therapy and into other GI cancers. We look forward to providing a further update by the end of the year. Now turning to CX-801, our masked interferon alfa-2b program being evaluated in checkpoint refractory melanoma.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We see CX-801 as a new and exciting opportunity to reprogram the immune responsiveness of solid tumors, and we continue to be pleased with the progress of the ongoing phase I study, both as monotherapy and in combination with KEYTRUDA. Starting with monotherapy, we've reached the fourth dose in dose escalation, and to date, CX-801 monotherapy has been generally well-tolerated, including at dose levels exceeding those achieved with commercially available unmasked interferon alfa-2b.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Initial biomarker data for CX-801 monotherapy presented previously have reinforced our mechanism of action hypothesis for CX-801 in combination with KEYTRUDA. We continue to make solid progress in the phase I combination study and have now successfully cleared the third dose level and enrollment is ongoing. We look forward to sharing initial clinical data from the phase I study in melanoma in the first half of 2027.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Before I turn the call to Chris to walk through financials, I'd like to highlight our continued additional progress across the organization. During Q2, we announced a major expansion of our collaboration with Regeneron, focused on next-generation masked bispecific immunotherapies. This is the result of our continued strong scientific momentum and represents validation of CytomX's expertise in conditional activation, masking technologies, and protease biology.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We've also been very pleased recently to have strengthened the organization through key additions to the Board and Executive Team as we prepare CytomX for the coming phase of growth and development. In May, we were delighted to welcome Mamata Gokhale as our Senior Vice President of Regulatory Affairs. Earlier this week, we announced the appointment of Alejandra Carvajal as our new Chief Legal Officer.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Additionally, as we approach late-phase development for Varseta-M in CRC, we are thrilled to have welcomed Dr. Charles Fuchs to our board of directors. Charlie's a highly accomplished oncology leader, most recently serving as Chief Medical Officer of Tubulis.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Prior to that, he led Global Oncology Development at Roche/Genentech after transitioning to industry from a long and distinguished career in academia as a global leader in gastrointestinal cancer. Welcome, everyone to the CytomX team. With that, I'll now transition the call over to Chris.

[Chris Ogden, CFO at CytomX Therapeutics]

Thank you, Sean. As Sean highlighted, we are making important progress across the increasingly broad Varseta-M development plan, with capital allocated to unlocking multiple layers of value creation over the near and long term.

[Chris Ogden, CFO at CytomX Therapeutics]

With our current balance sheet, we project cash runway to at least the second half of 2028, which positions us to advance Varseta into its first potential registrational study, pursue combination development to bring Varseta-M into earlier line CRC, and invest in the broader potential of Varseta in multiple EpCAM expressing indications.

[Chris Ogden, CFO at CytomX Therapeutics]

With that, I'm going to walk through our second quarter financial results. As of June 30th, 2026, we ended the quarter with $330.3 million in cash equivalents, and investments versus $346.7 million in cash as of March 31st, 2026.

[Chris Ogden, CFO at CytomX Therapeutics]

The cash balance as of June 30th, 2026, does not include the additional $37 million payment received from Regeneron in July, following the selection of two additional targets under the expanded collaboration.

[Chris Ogden, CFO at CytomX Therapeutics]

Looking at revenue and operating expenses for the quarter. Total revenue was $1.4 million, compared to $18.7 million in the second quarter of 2025. The decrease in revenue was primarily attributed to the conclusion of the BMS collaboration in 2025 and for the Astellas collaboration in the first half of 2026.

[Chris Ogden, CFO at CytomX Therapeutics]

Operating expenses for the second quarter were $25.2 million, compared to $19.9 million in the second quarter of 2025. R&D expenses were $17.6 million during the second quarter, representing an increase of $4.3 million versus the second quarter of 2025, primarily due to manufacturing activities for Varseta-M, as well as increased personnel-related costs and general research and development expenses.

[Chris Ogden, CFO at CytomX Therapeutics]

General and administrative expenses increased by $1 million during the three months ending June 30th, 2026 to $7.6 million, compared to $6.6 million for the corresponding period in 2025. Increased G&A expenses were primarily driven by higher consulting spend.

[Chris Ogden, CFO at CytomX Therapeutics]

We move through the second half of 2026, we will continue to be disciplined in capital allocation with a focus on progressing Varseta-M towards its first registrational study and accelerating investments to unlock the broader potential in the program. With that, I'll turn the call back to Sean for closing remarks.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Thanks, Chris. Thanks, everyone, for joining us today. We continue to be highly encouraged by the progress we're making with Varseta-M and the breadth of opportunities in front of us. CytomX is working diligently to execute toward multiple layers of value creation for Varseta-M, simultaneously advancing toward a potential registrational program in CRC, expanding into earlier line settings, and further evaluating additional EpCAM-expressing gastrointestinal cancers.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We also remain focused on advancing CX-801 and generating clinical data in patients with advanced melanoma to inform the next phase of development for this program. We look forward to providing additional updates by the end of this year as these programs continue to advance. Before I conclude today's call, I want to sincerely thank and recognize the patients who participate in our studies, their families and caregivers, our clinical investigators, and our highly dedicated team at CytomX.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

With that, operator, let's go ahead and open up the call for Q&A.

[Operator]

Thank you. At this time, we will conduct a question and answer session. Our first question comes from the line of Michael Schmidt with Guggenheim. Please go ahead.

[Michael Schmidt, Analyst at Guggenheim]

Hey, guys. Thanks for taking my questions. Congrats on the progress. I had a question on these new studies. In these GI cancer expansion cohorts, could you just comment a bit about how you're approaching dose selection here and to what degree you can implement learnings from the colorectal cancer experience?

[Michael Schmidt, Analyst at Guggenheim]

Similarly, in the bevacizumab combination study in colorectal, maybe talk about how you're approaching dose selection for this combination and are you implementing the same GI prophylaxis into these cohorts that you're doing in the monotherapy dose optimization cohorts? Thanks so much.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Hi, Michael. Thanks for the great questions. First of all, we're obviously very excited to be moving into these additional GI indications with Varseta-M. As you know, the target is expressed not only in these other indications, but also in many other solid tumors, this is really just the beginning of the expansion of the program across multiple cancers, over time, beyond CRC.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

In terms of dose selection, obviously, these will be initially monotherapy cohorts, the dose selection we're not commenting on just yet, but is informed absolutely by the escalation, expansion, and optimization work that we've done in colorectal cancer over the last year or two. In terms of the bev combination in CRC, as we've reported previously, we are exploring Q2-week and Q4-week doses with schedules to align with the Q2-week bevacizumab schedule.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

The doses that we've started out there, it's obviously a dose-finding study to evaluate multiple doses of Varseta-M with bev over time, we didn't need to go all the way back to the beginning in dose escalation. We believe we started at meaningful doses of Varseta-M, and we're excited to see the data as it emerges.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We're on track, as we just commented, to present initial data in the first half of next year. To your last question on prophylaxis, yes, we are indeed utilizing the same loperamide budesonide prophylaxis strategy in the bev combo study.

[Michael Schmidt, Analyst at Guggenheim]

Thank you.

[Operator]

Thank you. Our next question comes from the line of Edward Tenthoff with Piper Sandler. Please go ahead.

[Edward Tenthoff, Analyst at Piper Sandler]

Great. Thank you very much. I really just have to say congratulations on the success across the board from team to clinical to really everything. You guys are just really growing this company nicely. I wanted to pick up on these combo CRC studies, appreciating that the first regulatory push is going to be monotherapy later lines.

[Edward Tenthoff, Analyst at Piper Sandler]

What do you see as the path forward here with combo in earlier line CRC? Maybe you can just sort of lay out when we could expect data and what you see as the potential requirements for future studies there. I appreciate it.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Thanks, Ted. Appreciate the comments. Well, maybe beginning with the bev combination, there's a lot of different reasons that we're doing this work, of course, given how foundational bev is in the treatment of colorectal cancer across multiple lines, early and late.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

The study will open up multiple opportunities. Potentially a 3rd-line study and obviously enable work in the 1st and 2nd line over time in combination with Varseta-M, potentially in combination with chemotherapy.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We do see this bev work that we're doing, as I know others do, as really foundational to broadening the program across multiple lines over time. We're also super excited to be getting the chemo combination going with 5-FU later this year which is, of course, designed to bring Varseta-M initially into the 2nd line to replace irinotecan, where irinotecan FOLFIRI is most commonly used.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

It's not infrequently used in the front line, as you know, but most commonly used in the 2nd line. This irinotecan replacement strategy is really going to be enabled by this first step of the phase I, II study that we'll launch in Q4. Obviously, a little too early to be able to comment on potential registrational paths in those earlier lines, but we do see that these combination studies unlock enormous potential in the coming years.

[Edward Tenthoff, Analyst at Piper Sandler]

Yeah, totally get that. If I may, just one quick one for Chris. With the milestone or the payment from Regeneron in the third quarter, would that be recognized? You didn't recognize that in the second quarter. Would it be recognized fully in revenues in the third quarter? Thanks.

[Chris Ogden, CFO at CytomX Therapeutics]

Yeah. Great question, Ted. First, just to emphasize, we're obviously thrilled to be expanding the collaboration with Regeneron. It's based on a few hard years of work from the research team, and I think just a reflection of the foundational science. The payment, just a reminder, was $37 million for two additional programs.

[Chris Ogden, CFO at CytomX Therapeutics]

That takes our pro forma cash to about $367 million. That $37 million will be recognized as we do the work and make progress with Regeneron. Those obviously are pre-clinical projects, so do take a number of years. I should expect that to play out over a few years at least.

[Edward Tenthoff, Analyst at Piper Sandler]

Great. Thanks, guys.

[Operator]

Thank you. Our next question comes from the line of Anupam Rama with J.P. Morgan. Please go ahead.

[Joy Shao, Analyst at J.P. Morgan]

Hey, guys. This is Joy on for Anupam. Thanks so much for taking our question. I know you've previously said that a 10%-20% grade 3 diarrhea rate would be acceptable for the late-line CRC population. I think there is a fear that if the rate is on the higher end of this range in your next update by year-end 2026, there could be a risk to moving the product upstream. Just how would you respond to this pushback? Thanks so much.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Thanks for the question. An area of the program that we're obviously highly focused on at the moment as we move through our monotherapy dose optimization cohorts, where as we reported in our data update in March, our early experience with the prophylaxis strategy of loperamide and budesonide was very encouraging with the rate of grade 3 diarrhea after the first couple of months of experience having been brought down to 10%.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

A really strong start. The work that we've done and I think that many others have done in looking at when we think about risk-benefit of Varseta-M in the context of grade 3 diarrhea, that 10%-20% number is what we've been discussing and others have been discussing with us.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

At the end of the day, this drug, when you think about the unmet need in not just the late line, but actually even in the earlier lines of CRC treatment, where, for example, even in the second line I don't think we can say that outcomes in the second line are terrific for patients today. It's all going to be about risk benefit.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We know we've got a very active drug here in Varseta-M that targets EpCAM with a topoisomerase I inhibitor and has shown just really impressive activity in a patient population so far, which has been, as we mentioned in our comments, really quite late line. More than half our patients fourth line or later. It's all going to be risk benefit, I think, and this is going to evolve over time.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

I would also say that we will continue to learn more and more over time about the etiology of this adverse event, the etiology of diarrhea, in these patients, time to onset, impact of prophylaxis, time to resolution. This will be an ongoing element of the program that we'll continue, I think, to increasingly understand and manage. We'll just keep doing that work.

[Operator]

Thank you. Our next question comes from the line of Etzer Darout with Barclays. Please go ahead.

[Etzer Darout, Analyst at Barclays]

Great. Thanks for taking the question. Apologize for the background noise. Just a couple of questions for me. First, Sean, are you targeting a certain amount of follow-up time for the CRC late-line update by year-end, given that the study was enrolled in April?

[Etzer Darout, Analyst at Barclays]

Secondly, curious on the biliary tract and on the pancreatic ductal cancer, if you can comment maybe on your thoughts around expression levels of EpCAM in those two cohorts of patients. Thank you.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Yeah. Hi, Etzer. Thanks for the questions. In terms of follow-up, great question. What we're working towards, in terms of the next update is an update across the entire 113-patient study that will include data from the ongoing 40 patients in dose optimization.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

As we've done in the past, our goal is to communicate data from the optimization cohorts when it is sufficiently mature to have a preliminary estimate of progression-free survival. We think that will be most helpful for investors, and that's, as you know, the approach that we took coming into the last update in March of this year.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Another important update that we'll have by the end of the year will be the first look at overall survival for this drug in CRC, and that will come from the patients in the escalation and expansion phases.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

I think that's going to be an important communication, and of course, that number will be quite foundational in driving our decision-making on what the first registrational, the first pivotal study looks like in the first half of next year. As always, our goal is to communicate data when it's mature enough to be most meaningful for all stakeholders.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Great question on the biliary tract and pancreatic tumor types. EpCAM is expressed at some level in just about all patients, based on work that's in the literature and also prevalent studies that we've done ourselves with our own validated IHC assay.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

EpCAM high patients, depending upon how you define it is about 50%-60%. It's a pretty significant number. The reason that we're planning to select is it's just a starting point for these tumor types.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We think it makes sense to at least start in high EpCAM expressing with high to be defined. We haven't yet disclosed what that cutoff will be. That will come at a later date. We do think it makes sense to start there, not because we really know anything at this point about the relationship between target level and activity of the drug, because of course in CRC, every patient's high, so it didn't really give us that information.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

That's something that we'll learn about over time. I would think over time as well, we'll be interested to learn what Varseta-M can do in tumors, maybe with lower expression, because we're in the early days of learning about EpCAM now as a validated oncology target for the first time.

[Etzer Darout, Analyst at Barclays]

Great. Thanks, Sean. Congrats on the progress.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Thank you.

[Operator]

Thank you. Our next question comes from the line of Roger Song with Jefferies. Please go ahead.

[Nabil Ahmed, Analyst at Jefferies]

Hey, team. Thanks for the update. This is Nabil on for Roger. Thanks for taking our questions. First, just curious, as you get close to the year-end update and the planned registrational starting the first half of next year, what pieces of the puzzle are becoming a little bit more clear?

[Nabil Ahmed, Analyst at Jefferies]

Just curious, have you met with the FDA, and what do we need to resolve before we finalize that registration population, the endpoints? Then I had a follow-up question. Thank you.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Hi, Nabil. Very focused on that question right now, as we move through the back half of 2026, we anticipate multiple interactions with FDA across the program. As I said in my prepared remarks, we continue to see tremendous opportunity in either the fourth line or the third line settings with the drug candidate.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

In terms of what we need to pin down to go in one direction or the other. Obviously, we're looking at what do those patient populations look like? What is the relevant comparator arm in each of those populations?

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

As the data matures over the course of the rest of this year, what would the sizing of those studies need to be to be sufficiently powered to get to the result that we want? That's all in the mix right now. We will make a data-driven decision.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We will take a data-driven recommendation and plan to FDA and move forward with the first pivotal in the first half of next year. Everything remains on track in that regard. I believe you said you had another question.

[Nabil Ahmed, Analyst at Jefferies]

Thanks, Sean. Excited about the pipeline progress and just the platform potential we have here. I know it's early, but how are you approaching prior irinotecan or just prior topo I exposure in those non-CRC cohorts? Thank you.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

As you know, in the late line and really in the patients that we've treated to date across the phase I study, everyone has seen irinotecan over their treatment journey. That is an absolute function of being in the late line, of course.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

In the earlier lines, as I said, our goal is to get initially, over time, into the second line to evaluate the replacement of irinotecan. That is an objective that is very much being facilitated by the phase I/II study we plan to start in Q4 this year to get initial experience of Varseta-M in combination with the regimen components, putting Varseta-M in place of irinotecan.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

That will be a very important experience, and we're excited to get that work going because, I think maybe this is the point that you're alluding to, we're obviously all very excited to see what Varseta-M can do in irinotecan-naive patients.

[Chris Ogden, CFO at CytomX Therapeutics]

I'd also just add, Nabil, that as we gain experience with Varseta in combination with chemotherapy, that could certainly, over time, apply to other indications. As we learn about dosing schedule and how those things can combine. I think the work could, of course, synergize as we learn about new indications and combinations in general.

[Nabil Ahmed, Analyst at Jefferies]

Excellent. Thanks for taking our questions.

[Operator]

Thank you. Our next question comes from the line of Kalpit Patel with Wolfe Research. Please go ahead.

[Guganand Palani, Analyst at Wolfe Research]

Hey, thanks for taking the question. This is Guganand for Kalpit Patel. A few quick ones on our end. The timing of the monotherapy readout is by year-end. Is that mainly so you might be able to accumulate PFS data in addition to ORR?

[Guganand Palani, Analyst at Wolfe Research]

Can we expect the mature PFS data in the update later this year? What's your bar for success or a good outcome on median PFS in your view? Thirdly, on the pivotal study, what are your thoughts on the control arm in the registrational study? Would the FDA require lonsurf/bev as a comparator? Thank you.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Yeah. Hi, great questions. In terms of the monotherapy readout, I think as we discussed a little earlier in the call, our plan is to communicate data when we do indeed have an initial read on PFS for the optimization cohorts that we've been running that we had fully enrolled by the end of April.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We're on track as that data is maturing in real time. I should say here that our baseline assumption for the first registrational study is that the primary endpoint will be overall survival.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

That is, we think, most likely in a late-line colorectal cancer population. PFS and ultimately OS are going to be the most important metrics coming out from the phase I study. For that reason, we do plan to communicate, or we will wait to communicate until we have an initial sense of PFS.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

That's exactly what we did with the escalation and expansion cohorts in March of this year. In terms of the bar for success, I think it connects quite closely to your third question about control arms, of course, and that relates very much to whether we run this first pivotal in the third line or the forth line, both of which, as I've mentioned, we see as very compelling opportunities for building significant value in the company and helping patients.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

In the fourth line, the most likely comparator would be something like fruquintinib or fruquintinib and regorafenib, perhaps physician's choice. Those are all options that we're looking at in the fourth line. I think you're right. I think in the third line, we assume that the comparator there would most likely be bevacizumab plus LONSURF.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Just lastly, in terms of what success looks like, we just continue to point to the benchmarks. The benchmarks in terms of monotherapy treatments in the fourth line, you've got response rates that are very low in the low single digits, 1%-2%, and just a few months of progression-free survival, and five to six months of overall survival.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

With bev LONSURF in the third line, perhaps 4.5months-5.5 Months of PFS, nine to 10 months of OS. We reported, as you may recall, in March in our update across the study progression-free survival at the top two doses, which were now in optimization, 8.6 and 10 MPK. We presented a preliminary PFS of 6.8 months - 7.1 months. Obviously very encouraged by that.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

We'll see how the data continues to shape up, but we think we've got terrific options here whichever way we go.

[Guganand Palani, Analyst at Wolfe Research]

Awesome. Thank you.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

You're welcome.

[Operator]

Thank you. I'm not showing any further questions in the queue. I would now like to turn it back over to Dr. Sean McCarthy, Chairman and CEO, for closing remarks.

[Sean McCarthy, CEO and Chairman at CytomX Therapeutics]

Thanks very much. I'd just like to, again, thank everyone for tuning in today and following our progress. We're very excited about 2026 so far, and we look forward to providing additional updates as we move to the back end of the year. Thank you very much.

[Operator]

Thank you for your participation in today's conference. This does conclude the program. You may now disconnect.

Participants

Executives

• Chris Ogden, CFO
• Sean McCarthy, CEO and Chairman

Analysts

• Michael Schmidt, Analyst at Guggenheim
• Edward Tenthoff, Analyst at Piper Sandler
• Joy Shao, Analyst at J.P. Morgan
• Etzer Darout, Analyst at Barclays
• Nabil Ahmed, Analyst at Jefferies
• Guganand Palani, Analyst at Wolfe Research