Sean McCarthy
Analyst · Barclays. The floor is yours
Thank you, Chris, and good afternoon, everyone. Thanks for joining us for an update on recent progress at CytomX. Our mission at CytomX is to destroy cancer differently, and we're focused on leveraging our Probody platform to deliver differentiated medicines for people with cancer. CytomX's clinical achievements and learnings to date continue to highlight the broad applicability and scientific depth of our platform. Probody therapeutics are designed to achieve conditional activation of biologic therapies in tumor tissue, and we now have clinical experience with this important approach in more than 500 patients, many of whom have significantly benefited. Importantly, we have shown the potential of the platform to improve the therapeutic window across multiple biologic modalities including checkpoint inhibitors, antibody drug conjugates, T cell bispecifics and cytokines. These achievements are the result of our deep scientific expertise in biologic masking and in mapping the protease tumor microenvironment. Our continuous learning in the field of conditional activation is central to our conviction that our platform and pipeline has the potential to deliver breakthrough medicines for cancer patients. Conditional activation of biologics is an area of cancer R&D that is increasingly recognized in the industry as an important new frontier. Localization of cancer therapy via conditional activation offers immense promise and CytomX is at the forefront of this field. Innovation takes time and persistence and along the company building journey. To make the biggest difference, we must from time to time, take bold, decisive action and prioritize the opportunities most likely to deliver meaningful impact to patients. Last quarter, we made the difficult decision to restructure the company in order to focus our internal resources on our wholly-owned next-generation pipeline and on our partner programs. As a result, CytomX remains strong, it's funded into 2025 and is well positioned for the future. Our current pipeline spans from preclinical Phase 2 across multiple modalities and is addressing many important areas of unmet needed oncology. I'd now like to briefly review our lead programs. I'd like to start with our wholly-owned next-generation pipeline candidates, CX-2051 and CX-801. Now for these programs, we have selected previously validated targets EpCAM and interferon alpha-2B, respectively, that have historically been limited in their potential due to systemic toxicities. In the molecular design of CX-2051 and CX-801, we have incorporated our platform expertise and clinical learnings to optimize predictive therapeutic index in order to potentially broaden the clinical utility of these promising targets through conditional activation. Focusing now on CX-2051. EpCAM has been regarded as a high potential oncology target for decades and has been clinically validated by others. However, efforts to generate systemic anti-EpCAM therapeutics have to date not been successful due to toxicities in epithelial tissues. At the World ADC Conference during Q3, we were pleased to unveil CX-2051 as our newest conditionally activated ADC. 2051 is tailored to optimize the therapeutic index for EpCAM-expressing epithelial cancers by matching the target with payload mechanism of action and with tumor sensitivity. We selected cathodes in a topoisomerase 1 inhibitor as the payload for this program based on the well-characterized profile of this class and the strong clinical activity observed with TOPO-1-inhibiting ADCs, including, for example, the recent groundbreaking breast cancer data for N HER2. At World ADC, our data presented for 2051 demonstrated a wide predictive therapeutic index and strong preclinical activity and tolerability in multiple preclinical models, including in colorectal cancer. The expression profile of EpCAM and the tumor sensitivity profile of the camptothecin payload provide an exciting clinical path forward for this program, and we anticipate filing an IND for this novel ADC in the second half of 2023. Turning now to CX-801, our conditionally-activated interferon alpha-2b, the lead program within our broad efforts in the cytokine field. At SITC later this week, we will share preclinical data for CX-801, highlighting its potential to improve therapeutic window versus unmasked interferon. Interferon alpha-2b is an approved immunotherapeutic that has demonstrated clinical activity in multiple cancer types and we believe provides a potentially superior approach to activating antitumor immune responses to IL-2, IL-12 and IL-15. Interferon alpha stimulates antigen-presenting cells to activate cytotoxic T cells and combines effectively with checkpoint inhibition, offering tremendous potential to unlock checkpoint refractory and/or resistant cancers. However, the powerful anticancer activity of interferon alpha has thus been difficult to harness due to its systemic toxicity. For CX-801, the data to be presented at SITC show a wide therapeutic index with an enhanced tolerability profile versus unmasked interferon without limiting its potent antitumor effects. Importantly, these data also highlights CX-801's preferential activity in the tumor microenvironment as well as the potential for synergistic effects when combined with checkpoint inhibition. We believe CX-801 has the potential to become a unique centerpiece of combination therapy for a wide range of tumor types, and we aim to rapidly advance this potentially best-in-class program towards clinical evaluation with an IND filing targeted for the second half of 2023. Moving on now to our clinical stage pipeline. We continue to work intensively with our partners to advance multiple Probody therapeutic programs. Our work with Bristol-Myers Squibb is making important progress, including with BMS-986249, the Probody version of ipilimumab. At ESMO in September, BMS presented promising updated Phase 1 data from an ongoing Phase 1/2 study in patients with advanced cancers. We are particularly encouraged by the safety profile and clinical activity reported from the Phase 1 study to date. Both as monotherapy and in combination with nivolumab, 249 appears to be tolerated at higher doses than standard ipilimumab clinical dosing. Clinical activity was demonstrated in multiple tumor types, including melanoma, and a particularly encouraging case study of a response in microsatellite stable colorectal cancer. CTLA-4 continues to be an important target and a foundational immuno-oncology strategy, but CTLA-4 blockade has a narrow therapeutic window. The ESMO 2022 update provides continued evidence for the Probody platform, enabling higher and potentially more efficacious doses of anti-CTLA-4 therapy. BMS continues to evaluate 249 in a randomized Phase 2 study in combination with nivo versus ipi plus nivo in patients with advanced melanoma. The combination is also being studied in advanced hepatocellular carcinoma, castration-resistant prostate cancer and in triple-negative breast cancer. During Q3, BMS also highlighted our collaborative work on CTLA-4 in the SITC webinar series in a presentation titled Building on the Legacy of Ipilimumab. This presentation focused on the company's portfolio of next-generation anti-CTLA-4 antibodies to which the Probody strategy is a core focus. BMS also continues to study the nonfucosylated CTLA-4 targeting Probody BMS-986288 in Phase 1 both as monotherapy and also in combination with nivo in patients with advanced solid tumors. This strategy is aimed at enhancing the clinical benefit of ipilimumab through superior APC-mediated T-cell priming. BMS will be presenting a poster at SITC this week, focused on the non-mass version of 288, BMS-986218, and this poster will include preclinical data for 288, the Probody, which continues to advance in the clinic. We continue to be excited to be playing such an important role in BMS next-generation CTLA-4 efforts, and we look forward to future clinical updates on these programs over time. Moving on to CX-2029, our CD71 or transferrin receptor directed ADC, partnered with AbbVie. CD71 has long been recognized as an attractive target for cancer therapy because of its efficiency as an internalizing transporter and because it's highly expressed in many solid and hematologic tumors. However, this target has previously been undruggable due to its expression on many normal tissues. CX-2029 is a conditionally-activated Probody ADC targeted to CD71 that has demonstrated favorable tolerability and encouraging antitumor activity in Phase 1 and subsequently has advanced into a multi-cohort Phase 2 expansion study. Enrollment into the CX-2029 expansion phase is now complete in all three solid tumor types. A data update for the squamous lung cohort is expected in the fourth quarter of 2022. Additionally, data from the esophageal gastroesophageal junction cancer cohort continue to mature. We anticipate dialogue with our partner, AbbVie, as to the next steps for this program. Thus far on the call, we have discussed the application of our versatile technology to three biologic modalities, ADCs, cytokines and checkpoint inhibitors. I would now like to move to our fourth modality, T-cell engaging bispecific antibodies. Localization of the powerful activity of T cell engagers is a key goal in cancer R&D, and we believe our platform is very well suited to address this challenge. In September in Cancer Research, we published preclinical data demonstrating that a conditionally active bispecific EGFR-CD3 Probody could expand the safety window while maintaining anticancer activity of this potent target combination. This work has led to the clinical candidate, CX-904, and we are now well underway with Phase 1 dose escalation for this program with the goal of assessing safety and selecting a go-forward dose for subsequent expansions in EGFR positive tumor types. CX-904 is partnered with Amgen in a global co-development collaboration, and we believe this T cell engager has broad potential across many cancers, and we look forward to providing future updates. Let me now turn the call over to Chris to provide you with a financial overview for the quarter.