CytomX Therapeutics Q2 2025 Earnings Report

CytomX Therapeutics EPS Results

• Actual EPS: N/A
• Consensus EPS: -$0.05
• Beat/Miss: N/A
• One Year Ago EPS: N/A

CytomX Therapeutics Revenue Results

• Actual Revenue: N/A
• Expected Revenue: $19.10 million
• Beat/Miss: N/A
• YoY Revenue Growth: N/A

CytomX Therapeutics Announcement Details

• Quarter: Q2 2025
• Date: 8/7/2025
• Time: After Market Closes
• Conference Call Date: Thursday, August 7, 2025
• Conference Call Time: 5:00PM ET

CytomX Therapeutics (NASDAQ:CTMX), an oncology-focused biopharmaceutical company, focuses on developing novel conditionally activated biologics localized to the tumor microenvironment. The company utilizes conditional activation platform technology for oncology biologics research and development comprising the validation of targets for antibody-drug conjugates (ADCs), opening therapeutic window for novel T-cell engagers (TCEs) targeting solid tumors, and increasing the therapeutic index for immune modulators, such as cytokines; and PROBODY platform in preclinical research in areas outside of oncology. It also develops CX-904, a T-cell-engaging bispecific antibody targeting the epidermal growth factor receptor (EGFR) on tumor cells and the CD3 receptor on T cells; CX-2051, a conditionally activated ADC for optimizing the therapeutic index for EpCAM-expressing epithelial cancers, including colorectal cancer; and CX-801, an interferon alpha-2b PROBODY cytokine. In addition, the company's development pipeline comprises CX-2029, a conditional activated ADC targeting CD71; and BMS-986288, a PROBODY version of non-fucosylated ipilimumab. It has strategic collaborations with Amgen, Astellas, Bristol Myers Squibb, Regeneron, and Moderna. CytomX Therapeutics, Inc. was founded in 2008 and is headquartered in South San Francisco, California.

CytomX Therapeutics Q2 2025 Earnings Call Transcript

Key Takeaways

• Positive Sentiment: Initial Phase I data for CX-2051 in fifth-line colorectal cancer showed a 28% confirmed overall response rate, 94% disease control and 5.8 months median progression-free survival, with no classic EpCAM toxicities observed.
• Positive Sentiment: Dose expansion cohorts at 7.2, 8.6 and 10 mg/kg are enrolling ~20 patients each, and an updated dataset of ~70 patients is on track for Q1 2026 to inform Phase II dose selection.
• Positive Sentiment: CX-801 masked interferon α-2B program has dosed its first patient in combination with Keytruda in metastatic melanoma, with translational monotherapy data expected in Q4 2025 and combo data in 2026.
• Positive Sentiment: Completed a $100 million follow-on equity offering, ending Q2 2025 with $158.1 million in cash and investments and a runway into 2027 under current plans.
• Neutral Sentiment: Ongoing research collaborations, notably on T-cell engagers with Regeneron and Astellas, could generate near-term milestones, reflecting a capital-efficient partnership strategy.

Presentation

[Operator]

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

[Chris Ogden, CFO at CytomX Therapeutics]

Thank you. Good afternoon, and thank you for joining us. Before we begin, I'd like to remind everyone that during this call, we will be making forward looking statements. Because forward looking statements relate to the future, they are 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.

[Chris Ogden, CFO at CytomX Therapeutics]

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 second quarter twenty twenty five 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. 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 Doctor. 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'll then conclude with a Q and A session. With that, I'll now turn the call over to Sean.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Thanks, Chris, and good afternoon, everyone. We're thrilled to be here today to review our progress for the second quarter, highlighted by the exciting clinical data we announced in May for CX-two thousand and fifty one, our Probody antibody drug conjugate targeting EpCAM, which we view as having significant potential in colorectal cancer and potentially many other tumor types.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

We're also making great progress with our second current clinical program, CX-eight zero one, that I'll come to a little later. I'll focus initially today on CX-two thousand and fifty one and our work in colorectal cancer, which I'll refer to you from here on as CRC. CRC remains one of the biggest unmet needs in oncology with approximately one point nine million patients diagnosed per year on a global basis. This disease burden is expected to increase considerably over the next couple of decades to more than three million and is currently the second leading cause of death by cancer worldwide. Despite many advances across many other cancer types in recent years, CRC has seen little impact from innovation over this period of time, resulting in current five year survival rates in metastatic CRC of about thirteen percent.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

New treatments like antibody drug conjugates are urgently needed to treat this cancer. In other solid tumor types, ADCs such as Enhertu, Trodelvy, and Elihir have made a big difference for patients, but ADCs have yet to break through in CRC, representing a major scientific, clinical, and commercial opportunity. At CytomX, we have intentionally designed CX-two 51 to address this opportunity, building on years of experience in how to optimally leverage our Probody technology for the maximum benefit of cancer patients. Let me recap the key design elements of CX-two 51. ETCAM is a very highly expressed target in CRC, making it very attractive for an ADC.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

The payload on CX-two 51 is a topoisomerase one inhibitor, which is ideally matched to CRC, where the topoisomerase inhibitor, orinotecan, has been a core component of the standard of care for many years. And thirdly, critically, CX-two thousand and fifty one uses CytomX Probody Masking Technology to limit binding in normal tissues, something that has thwarted previous attempts to drug EpCAM. Our initial experience with CX-two thousand and fifty one in the clinic announced in May is very encouraging. We have focused on Phase I clinical evaluation exclusively in CRC with the goal of delivering clear clinical proof of concept in this high area of unmet need. I'd like to briefly recap the CX-two thousand and fifty one initial phase one data from May.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

For context, CX-two thousand and fifty one has initially been studied in a fifth line CRC patient population, where approved standard of care therapies are typically associated with one percent to two percent response rates and progression free survival of only two to three months. In comparison to these benchmarks, CX-two thousand fifty one has demonstrated robust clinical activity with a twenty eight percent confirmed overall response rate, ninety four percent disease control, and five point eight months of preliminary progression free survival in the first 18 efficacy evaluable patients at relevant dose levels. We're also encouraged to have observed clinical activity, including confirmed objective responses across a relatively wide range of doses. Our initial data has also validated expression is abundant in late line CRC with every evaluable patient having high target levels. This is important because it suggests that CX-two thousand and fifty one may broadly address CRC and may not require patient selection, potentially a significant commercial advantage.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Furthermore, our CX-two thousand and fifty one masking strategy has succeeded in avoiding classic EpCAM toxicities such as pancreatitis that have impeded the successful development of drugs against this target previously. In terms of next steps, we have initiated dose expansions at doses of seven point two, eight point six, and ten milligrams per kilogram administered every three weeks, and we are targeting enrollment of approximately 20 patients at each dose level. Enrollment is going well, and we remain on track for an updated dataset from a total of about 70 patients in Q1 twenty twenty six. Our goals for the dose expansions are to more fully characterize the dose response of CX-two thousand and fifty one, both in terms of clinical activity and safety, with a goal to inform dose selection for phase two. In terms of safety, the most common adverse events in the interim phase one data were diarrhea, nausea, vomiting, and anemia.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

In the expansion phase, we're paying particular attention to management of diarrhea using prophylactic medications, and we'll continue to iterate and refine our AE management strategies to best position CX-two thousand and fifty one for phase two and beyond. In parallel to enrolling the expansion cohorts, we are in the process of developing our Phase II strategy in late line CRC and planning for potential initiation during the 2026. While detailed next steps will of course be data dependent, our current view is that the next study would likely evaluate CX-two thousand and fifty one monotherapy in fourth line CRC based on the high unmet need, the potential speed to market, and the multibillion dollar market opportunity we see in this treatment setting. Looking ahead to the longer term, CX-two thousand and fifty one is also anticipated to have potential in earlier lines of CRC therapy and ultimately may be positioned, we believe, to replace irinotecan as a foundational component of CRC treatment. In support of this strategy, we anticipate starting combination studies in CRC in 2026.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Now turning to CX-eight zero one, our masked interferon alpha-2B program that we're developing in combination with the PD-one inhibitor Keytruda. Interferon alpha is a powerful immune system modulator with known anticancer activity across multiple tumor types, including renal cancer, bladder cancer, and melanoma. But it's fallen out of clinical use in oncology due to its poor tolerability. We designed CX-eight zero one to really clamp down on the undesired broad systemic activity of interferon and localized activity to the tumor microenvironment. In May 2025, during Q2, we dosed the first patient in the combination arm of our Phase I study with Keytruda.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

This study is focused in metastatic melanoma, and we're targeting initial data for the combination in 2026. In the fourth quarter of this year, we anticipate providing a first look at translational data for monotherapy CX-eight zero one impaired tumor biopsies and specifically how it's modulating the tumor microenvironment, including potential upregulation of interferon stimulated genes like PD L1. Positive early results here would provide evidence that the mechanism of action is working as designed, underpinning our rationale for the KEYTRUDA combination and supporting our vision of turning cold tumors hot with this novel immunotherapy. We look forward to providing this initial CX-eight zero one translational update in Q4 this year. With that, let me turn the call over to Chris for updates on our finances.

[Chris Ogden, CFO at CytomX Therapeutics]

Thank you, Sean. Echoing Sean's earlier comments, the second quarter was important as we presented initial CX-two 51 phase one data that informed clear next steps for the program. From a capital formation standpoint, we are pleased to have completed a $100,000,000 follow on offering with a top tier group of shareholders, further underscoring CX2051's potential. Following the execution of the financing, CytomX is in a strong financial position with projected cash runway to the 2027.

[Chris Ogden, CFO at CytomX Therapeutics]

Of note, our cash guidance does not assume any additional milestones from existing collaborations or any new business development. Outside of CX-two thousand fifty one, we will continue to employ a focused capital allocation approach, including for CX-eight zero one, where we are aiming to deliver initial proof of concept in combination with Keytruda in melanoma. In terms of our research collaborations, we continue to view partnering as a capital efficient way to extend the reach of our technology and drive increased long term value. A key current focus in our collaborations is T cell engagers, where, for example, we have momentum with partners Regeneron and Astellas, and have the potential to earn milestones over the next one to two years. With that, I'm going walk through our second quarter financial results.

[Chris Ogden, CFO at CytomX Therapeutics]

As of 06/30/2025, we ended the quarter with $158,100,000 in cash, cash equivalents and investments versus $79,900,000 in cash at the end of the 2025. Total revenue was $18,700,000 compared to $25,100,000 in the 2024. The lower revenue was driven by the completion of our performance obligations in the BMS and Amgen collaborations, as well as decreased activity with Moderna. Operating expenses for the second quarter were $19,900,000 compared to $33,600,000 in the 2024. R and D expenses were $13,300,000 during the second quarter, representing a decrease of $11,900,000 versus the 2024.

[Chris Ogden, CFO at CytomX Therapeutics]

General and administrative expenses also decreased by $1,800,000 during the three months ending 06/30/2025, to $6,600,000 compared to $8,400,000 for the corresponding period in 2024, driven by lower personnel costs and lower legal and patent expenses. Overall, we will continue to maintain a disciplined data driven capital allocation approach in order to advance the most promising opportunities in our pipeline. With that, I'll turn the call back to Sean for closing remarks.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Thanks, Chris, and thanks everyone for joining us today. CytomX made tremendous progress during Q2, and we look forward to the second half as we set our sights on 2026 and in particular, next steps for the CX-two 51 program. With EpCAM, we believe we have unlocked a new approach to the treatment of late stage CRC, leveraging our proprietary platform technology and prior experience with masked ADCs. We view CX-two 51 as a first in class and highly differentiated asset with broad scope for value creation.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Based on the interim Phase I dose escalation results disclosed to date, we see a clear path forward to develop CX-two 51 in late line CRC, and we plan to execute against this opportunity as our top near term priority. We're excited to see phase one results in 2026 together with our next steps for the program. Regarding CX-eight zero one, we're executing a similarly focused strategy to CX-two thousand and fifty one in melanoma in order to generate proof of concept for the Keytruda combination. Positive data here would reestablish interferon as a potential new centerpiece of combination immunotherapy with broad potential across many immunologically cold tumors or for patients who become refractory to checkpoint inhibition. We look forward to advancing CX-eight zero one towards this vision.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Before I wrap up today's call, I want to sincerely thank and honor the patients who join our studies, their families, our clinical investigators, and our dedicated team here at CytomX. Your collective contributions are responsible for our advancements, and we're grateful for your help in getting us to where we are today. With that, operator, please go ahead and open up the call for Q and A.

[Operator]

Thank you. Our first question comes from the line of Edward Tinhoff with Piper Sandler. Your line is open.

[Edward Tenthoff, MD & Senior Research Analyst at Piper Sandler Companies]

Thank you very much, and congrats on all the progress this year. So my question has to do with the potential to move into earlier lines of colorectal therapy. What's going into those decisions and, how do you envision sort of announcing those trials? Thanks.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Yeah, hi Ted, thanks for the question. So as I mentioned, first of all, first and foremost, we're super focused on executing towards the late line opportunity. We see a terrific opportunity there to move really quickly in fourth line. Coming into the earlier lines obviously will be a key focus for us over time to really broaden the opportunity. That will require combination studies to assess the doses that we ultimately select for the Phase II for the monotherapy in the context of certain combinations to come into into third line and then of course into second line where the vision would be to replace irinotecan.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

So one clear opportunity there in terms of combinations given the extent of its use in treatment of CRC is to evaluate the combination with bevacizumab. And that's something that we're looking at carefully and we will be doing. I'm pretty sure in the future we need to obviously round out the Phase one study select our doses.

[Edward Tenthoff, MD & Senior Research Analyst at Piper Sandler Companies]

Excellent. That makes a lot of sense. Really helpful. Looking forward to it.

[Operator]

Thank you.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

You bet. As are we.

[Operator]

Please stand by for our next question. Our next question comes from the line of Nabil Nassar with Jefferies. Your line is open.

[Nabeel Nissar, Senior Associate at CytomX Therapeutics]

Hi, team. This is Nabil on for Roger. Thanks for the updates. Quick question regarding the rationale for value creation of EpCAM beyond CRC. Are we approaching this with partnerships, and what is the strategy?

[Nabeel Nissar, Senior Associate at CytomX Therapeutics]

Are we looking for a particular TAM, or is there a particular tumor indication that would fit better with your technology? Thank you.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Yeah, thanks for the question. It's a terrific opportunity to broaden the 2,051 development program outside of CRC. We do, of course, currently have our hands rather full with the scope and scale of the opportunity in colorectal alone. But just to restate, EpCAM is expressed in most solid tumors and in many of them at high levels. So for example, lung, pancreatic, gastric, endometrial, breast cancer.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

So there's an enormous opportunity here now that we have initial proof of concept in colorectal. So it is the kind of drug or the kind of profile of drug that over time could very well benefit from a partnership. We'll get there when the time is right. As I've said many times on these calls, we'll do the right deal or right deals at the right time. But that could certainly make sense in the future for value creation.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

But again, right now, over the next few months, I think it's important for us to be laser focused on really building value initially through the CRC opportunity.

[Nabeel Nissar, Senior Associate at CytomX Therapeutics]

Got it. Thank you.

[Operator]

Please stand by for our next question. Our next question comes from the line of Matt Biegler with OpCo. Your line is open.

[Matthew Biegler, Executive Director at Oppenheimer & Co. Inc.]

Hi, Thanks for the question and for the update. What do you think is the bar for accelerated approval in CRC right now, assuming you do go forward with like a monotherapy fourth line? I think, obviously, like the rule of thumb that the buy side loves to point to is the 30% RR, but we've recently seen an ESMO working group come out advocating as low as 20%, I think like given how poor salvage therapies work in this setting. So I'm just kind of curious if you had any thoughts on that or whether you think ORR is even the most relevant outcome versus PFS or OS or something like that. Thanks.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Yeah. Thanks, Matt. Great question, and of course, an exceedingly difficult one to answer at the moment. But given the activity that we've seen so far and the performance of 2,051 in this area of such enormous unmet medical need, we of course have to be thinking about strategies that could lead to an accelerated approval. We want to get this drug to patients as quickly as we possibly can.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

That said, there are two major considerations as we develop that strategy. One, there's not precedent for accelerated approval in the CRC setting based on ORR, as you know, that would be breaking new ground. More typically, we're looking at a patient population in a clinical setting where we're relying on PFS and of course ultimately OS endpoints. That said, the scope of the unmet need, the nature of the unmet need here is so high and our activity is so encouraging that we are considering it and we will at the right time have discussions with FDA. The second thing, of course, is just the overall regulatory uncertainty at the moment, which none us can ignore.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

But just to reiterate, of course, we're all aligned here in wanting to get this drug to patients by the fastest possible means.

[Matthew Biegler, Executive Director at Oppenheimer & Co. Inc.]

Makes sense. Appreciate it.

[Operator]

Thank you.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

You're welcome.

[Operator]

Please stand by for our next question. Our next question comes from the line of Anupam Rama with JPMorgan. Your line is open.

[Anupam Rama, Executive Director - Biotechnology Equity Research at JP Morgan]

Hey, guys. Thanks so much for taking the question. So on the preliminary eight zero one monotherapy data here in the fourth quarter, what are you looking for that might give you confidence in sort of the combination potential of this product with KEYTRUDA and melanoma? And I guess any thoughts on any risks of overlapping tox that you're going to be monitoring for? Thanks so much.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Yeah. Hey, Annabelle, great question. Happy to talk about eight zero one a little bit more. So first of all, there's actually very good precedent for mechanistically for PD-one, specifically KEYTRUDA and interferon alpha-2b having very powerful combination activity in melanoma. That's been shown by Merck in a somewhat earlier patient setting than we're currently working in.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

But nonetheless, they showed robust activity, but it was limited by significant incidence of grade three adverse events of various kinds, particularly immune adverse events. So we do know that this combination can be very effective in melanoma as a starting point. In terms of progression of our development plan for 08/2001, we're being very deliberate about it. We've escalated through several cohorts already of monotherapy just in a handful of patients to get initial experience with the drug. In that escalation, we've reported previously, we've already exceeded the clinically approved dose and clinically utilized dose of interferon alfa.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

So we've already made progress, which is consistent with masking showing an overall tolerability benefit. Most importantly though, that initial experience with just a few monotherapy patients ungated our ability to start the combination, which we did during Q2, as we just mentioned. And that really is the drug here. So we see the drug ultimately as being eight zero one plus KEYTRUDA, and we're now going to aggressively enroll that arm of the study, and that data will be reported next year. So the safety and efficacy data from the combination will come in 2026.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

In the meantime, with this handful of monotherapy patients that we've treated, we have been studying and will continue to study a series of paired tumor biopsies to interrogate the immune tumor microenvironment to look at how in microenvironment the unmasked interferon is modulating immune cells and also inducing what we would expect it to do, which is to introduce interferon regulated genes, which include PD L1, which really underscores the rationale for the combination with a checkpoint inhibitor like Keytruda. So the data that we're planning to share in Q4 will be from a handful of patients. It will be biopsy data initially. We're not expecting in this initial small number of patients to have any kind of initial ORR assessment is going to be translational data, but very important and hopefully very informative data that shows us that at the molecular level, the drug is behaving as we've designed it.

[Anupam Rama, Executive Director - Biotechnology Equity Research at JP Morgan]

Thanks so much for taking our question.

[Operator]

Thank you.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

You bet.

[Operator]

Please stand by for our next question. Our next question comes from the line of Peter Lawson with Barclays. Your line is open.

[Peter Lawson, MD - US Biotech Equity Analyst at Barclays Capital]

Great. Thanks so much. I apologize if this has been asked. I joined late. On the EpCAM ADC, so we've got the phase one update in Q1.

[Peter Lawson, MD - US Biotech Equity Analyst at Barclays Capital]

Kind of just if you could talk through the size of the data set we see and the scope of it, and kind of if we should expect to see durability also biomarker data.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Yeah. Thanks, Peter. Thanks for giving me the opportunity to recap some of our earlier comments on the call. It's very important. So as we said, we're super focused on generating this next dataset for 02/1951.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

We anticipate that in Q1 twenty twenty six, we'll have seventy and maybe a few more patients who have experience with the drug compared to the update, the initial disclosure in May, which was twenty five safety evaluable patients and eighteen efficacy evaluable. So by the time we get to Q1, data set should be quite a bit larger and predominantly across three dose levels seven point two, eight point six and ten mgskg, each of which were doses that we saw clinical activity for in that initial disclosure. By then, yeah, we would expect to have reasonable follow-up on the majority of those patients. And the other element of that update will be integration of that data into our go forward plan for phase two. So that's our current plan, is that the Q1 update will be a rounded out phase one dataset plus our strategy for moving forward into phase two. That's the current Thank you.

[Peter Lawson, MD - US Biotech Equity Analyst at Barclays Capital]

And that phase two, would that have a randomized component to it?

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

I think that's most likely. Yeah, we're still obviously collecting data from the phase one, so no decisions made yet. But we are of the general view that the next study would be randomized to a component or components of current standard of care in the fourth line, where unfortunately for patients today, the bar is very low. So we think that 2051 is very well positioned against those comparators. And we'll also be thinking through in the context of Project Optimus and also, of course, based on the full phase one dataset that we analyzed later this year and into Q1, whether that's one dose of two thousand and fifty one or maybe two, that remains to be decided.

[Peter Lawson, MD - US Biotech Equity Analyst at Barclays Capital]

Great. Thank you so much. Thanks for taking the questions. Thanks for the update.

[Operator]

You're very welcome. Our next question comes from the line of Mitchell Kapoor with H. C. Wainwright. Your line is open.

[Mitchell Kapoor, Director & Senior Biotechnology Analyst at H.C. Wainwright & Co., LLC]

Guys. Thanks for taking the question. You mentioned that there's quite a low bar for 02/1951. That makes a lot of sense. But thinking about what triggers and gono go move into the Phase two and fourth line as a monotherapy, can you just speak to what we should be looking for that would be indicative of a positive outcome that would immediately trigger looking to move into Phase two?

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Yeah. Hey, Mitch, thanks for the question. Well, again, just to recap our experience with the first 18 efficacy evaluable patients where across the three dose levels of seven point two, eight point six, and 10, we saw a confirmed ORR of twenty eight percent. So I think we all agree that that's very exciting and would set up a very clear go forward decision into the fourth line study. Number doesn't, of course, need to be as high as that to go forward.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

I don't think we're going to put a number on it today, but we've got a lot of room to maneuver, we think, with the data that we've already presented with CX-two thousand and fifty one as our data continues to mature.

[Mitchell Kapoor, Director & Senior Biotechnology Analyst at H.C. Wainwright & Co., LLC]

Okay, great. And just one more on CRC combos in earlier lines. Would you potentially advance multiple combinations and have any plans been discussed with the FDA on the combination strategy so far?

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Multiple combinations are certainly on the table. We need to be mindful of our resources at this point in time. As I mentioned, the place to start most likely would be the combination with Bev. We have yet to have significant conversations with FDA relating to go forward study design. That will come, of course, as our Phase one data continues to mature.

[Mitchell Kapoor, Director & Senior Biotechnology Analyst at H.C. Wainwright & Co., LLC]

Great. Thank you.

[Operator]

Thank you. Please stand by for our next question. Our next question comes from the line of Mayank Mamtani with B. Riley. Your line is open.

[Analyst]

Hi, this is Jeff from B. Riley for Mayank. Thank you for taking the questions. My first question is, given that CX-twelve fifty one's grade three diarrhea rates exceeded those of other TOP1 inhibitor ADCs, where you explore alternative mitigation strategies, such as the drug specific protease inhibitors or microbial modulation rather than relying solely on rapamide? My second question is, how much median follow-up are you expecting to have as a 1Q update?

[Analyst]

And are you planning to present data at ASCO GI in January 2026? Thank you.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Great. Thanks for the questions. So taking the first one relating to diarrhea. Yes, so as I mentioned on the call, that is one of the AEs that we're most focused on in this phase one study. We've learned a lot about it in the context of the data that we initially disclosed.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Just to recap what we're doing, as we discussed before, In the earlier part of this study, of course, as we wanted to understand the overall AE profile of this drug, we had not implemented any prophylactic measures for management of diarrhea. But we did earlier this year around the March timeframe, around the time that we were beginning to gear up some of these expansion studies. And so we continue to be focused on the use of loperamide as a prophylactic measure. We're going to learn a lot about that as we continue to execute on the expansions. And in terms of the incidence of grade three diarrhea in the study, about twenty percent.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

I want to remind everyone that in the early days of arinotecan development, that number was closer to thirty percent to forty percent. And we do know that TOPO-one inhibitors in the context of ADCs can also induce significant levels of grade three and higher diarrhea. So it's something we need to understand more about, something we need to manage. We're really exploring loperamide as a starting point. Your question on protease inhibitors is an interesting one.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

At this point, that would be very exploratory and we don't really have any evidence right now that protease biology is playing any role in the AE profile. So that may be something for future exploration. But thanks for the question. I think you have two more questions. But in terms of median follow-up, I guess there, what I would say is that, as I mentioned earlier, enrollment of the expansions has gone well.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

We're midway through 2025. So by the time we get to Q2 sorry, Q1 of next year, we'll have a pretty decent follow-up, we think, on the majority of these patients. So I can't give you a number. The study is still in progress. And of course, can't comment on ASCO GI twenty twenty six.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

We will plan to keep all of our options open in terms of where and exactly when we present data as is customary. But thanks for the question.

[Analyst]

Thank you. That's very helpful.

[Operator]

Thank you. Ladies and gentlemen, I'm showing no further questions in the queue. I would now like to turn the call back over to Doctor. Sean McCarthy, Chairman and CEO for closing remarks.

[Sean A. McCarthy, Chairman & CEO at CytomX Therapeutics]

Thanks everyone for joining us today. It's been a pleasure to recap our tremendous progress during 2025. We look forward to providing additional updates as we move through the second half of the year. So enjoy the rest of your day.

[Operator]

Ladies and gentlemen, that concludes today's conference call. Thank you for your participation. You may now disconnect.

Participants

Executives

• Chris Ogden, CFO
• Sean A. McCarthy, Chairman & CEO
• Nabeel Nissar, Senior Associate

Analysts

• Edward Tenthoff, MD & Senior Research Analyst at Piper Sandler Companies
• Matthew Biegler, Executive Director at Oppenheimer & Co. Inc.
• Anupam Rama, Executive Director - Biotechnology Equity Research at JP Morgan
• Peter Lawson, MD - US Biotech Equity Analyst at Barclays Capital
• Mitchell Kapoor, Director & Senior Biotechnology Analyst at H.C. Wainwright & Co., LLC
• Analyst