Sean McCarthy
Analyst · Cantor Fitzgerald. Your line is open
Thanks, Chris, and good afternoon, everyone. I'm very pleased to be here with you today to briefly review CytomX productive second quarter. At CytomX, we see a major opportunity to more effectively target therapeutic antibodies into disease tissue generating new classes of differentiated anti-cancer therapies as we have the best-in-class molecules against validated targets or first-in-class molecules against novel targets that we believe only our technology can address. Our innovative approach through antibody localization into diseased tissue is called the Probody platform. Probodies are fully recombinant antibody prodrugs comprised of a therapeutic antibody, a linker, and a mask designed in a way that the antibody can't see its target until the mask is removed. Mask removal is achieved specifically and selectively within cancer tissue by certain disease-associated proteins called proteases. Proteases are molecular scissors which play a key role in cancer cell invasion and metastasis. We take advantage of high-level of protease activity in cancer tissue to clip the mask off Probodies in the tumor allowing the underlying antibody to bind target and elicit its biological effect. Probody therapy takes off a localized target binding in diseased tissue while maintaining potency, reducing side effects, and enabling new targets of mechanisms to be translated into novel product opportunities. We see this as a really big idea backed by decades of antibody and protease biology research, by a deep knowledge of the biology of the tumor microenvironment, by our innovative protein engineering, and our robust intellectual property portfolio. We are the leader in this emerging field of therapeutic antibody localization with four clinical stage programs, strong partnerships, and we're the first to have shared clinical proof-of-concept with this novel approach. We aim to maintain our leadership in this field by aggressive development of our assets and our intellectual property. In the second quarter, our teams continued to make progress in advancing our novel Probody platform and our portfolio of innovative, wholly-owned, and partnered programs. Building on the strong body of clinical data, we have reported to-date including encouraging safety and efficacy profiles from our two lead wholly-owned programs CX-072, and CX-2009. Alongside our continued strong cash position, we're now setting the stage for further advancement of these unique and potentially differentiated assets. On this call, I'd like to provide brief updates on our programs and layout a roadmap for the next steps and future disclosures. Let me start with our most advanced program, the PD-L1 targeting probody, CX-072. Our vision for CX-072 is for this probody to become a differentiated centerpiece of combination anti-cancer therapy by enabling safer, more effective combinations. We've presented Phase I clinical data on CX-072 as monotherapy and in combination with the anti-CTLA-4 antibody, ipilimumab to support this vision. We are enthusiastic to move this program to the next stage in its development. During Q2, we reported updated data at ASCO 2019 from our ongoing monotherapy dose-expansion cohorts, studying CX-072 in multiple tumor types at the dose of 10 milligrams per kilogram. Data represented in poster form and also reviewed as part of a next-generation immunotherapy discussion session, lead by Dr. David Page of the Providence Cancer Center. Consistent with our previously presented Phase I dose-escalation data, these data continue to show a favorable safety profile for CX-072 when compared to conventional anti-PD-1 and PD-L1 antibodies. The efficacy profile of CX-072 also continued to mature, with robust evidence of anti-cancer activity being seen in patients with triple-negative breast cancer, anal squamous cell carcinoma, cutaneous squamous cell carcinoma, and on differentiated pleomorphic sarcoma. We expect to complete these initial expansion cohorts and decide our next steps for monotherapy CX-072 in the second half of 2019. To date, our monotherapy data for CX-072 supports the idea that it could become a safer foundation for combination therapy. The first such combination we set out to study in-depth in the clinic is CX-072 plus ipilimumab. We believe the combination of ipilimumab with other anti-PD agents continues to hold much promise, as recently demonstrated by the positive readout in the combination arm of BMS CheckMate 227 trial in lunch cancer. However, it's well accepted that the full potential of this IO/IO combination is limited by the profound toxicity of these mechanisms when used together. And it's important to note that BMS was limited to 1 mg/kg of ipi every six weeks in the 227-study compared to the full label dose of 3 mg/kg every three weeks. Our previously reported Phase I data has shown that CX-072 is generally well-tolerated with full dose ipilimumab. Moreover, we have reported deep and durable responses for this combination in advanced-stage patients. This Phase I work also established the maximum tolerated dose of the combination as 10 mg/kg of CX-072 and 3 mg/kg of ipilimumab. We are now in the process of initiating the next phase of development of this combination and will be providing additional details in the near future. Turning now to our second wholly owned program, CX-2009, a potentially first-in-class probody drug conjugate targeting CD166, a unique and broadly expressed tumor antigen. Because Probody therapeutics are designed to minimize binding of the drug to normal tissues, we believe we're in a unique position to address a new class of targets with attractive molecular features that were previously thought undruggable because of high expression on normal tissues. CD166 is an example of this kind of target. CD166 is highly and homogeneously expressed in multiple solid tumor types and might be considered an attractive target for a conventional antibody-drug conjugate, were it not for the fact that it's also present on most normal epithelial tissues. We think it's a promising target for a probody drug conjugate, however, since probodies allow us to more selectively target tumor tissue. CX-2009 is a CD166 targeting probody drug conjugate conjugated to the microtubule inhibitor DM4. During Q2, we presented updated data from the Phase 1 dose escalation trial of CX-2009 monotherapy at AACR. The focus of this trial was to get a first look at the safety and preliminary efficacy of this novel drug candidate in patients with select cancer types. Among patients who received greater than or equal to 4mg/kg of CX-2009, 38% achieved tumor shrinkage and 74% achieved stable disease or better at the time of their first on-treatment scan. Demonstrated anti-cancer activity included seven unconfirmed partial responses in breast cancer, ovarian cancer, and head and neck cancer. CX-2009 was generally well-tolerated. Despite the widespread expression of CD166 on normal tissues, no evidence of obvious on-target toxicity was observed, demonstrating the potential of Probody masking to address novel, first-in-class targets. We see this data as an encouraging start to the development of CX-2009 and we're currently working to refine the dose of this agent as we advance towards the initiation of Phase 2 studies potentially by the end of 2019. I'll now turn to our BMS and AbbVie partner programs. The lead program for our broad alliance with BMS is BMS-986249. This is an anti-CTLA4 Probody based on ipilimumab. This program is in a Phase 1/2 clinical study being run by BMS, evaluating the agent as monotherapy and in combination with Opdivo, nivolumab in advanced solid tumors. Based on progress with this initial clinical study, BMS is preparing to initiate a randomized Phase 2 clinical trial, comparing BMS-986249 plus Opdivo to ipilimumab plus Opdivo in patients with solid tumors. Upon the start of this study, CytomX will be entitled to a $10 million milestone payment. Naturally, we're pleased with this progress and we anticipate this study will be initiated in the second half of 2019. As a reminder, our alliance with BMS also extends to ongoing research on additional Probodies and BMS retains the right to select several additional targets for future research. The lead program from our alliance with AbbVie is CX-2029, a first-in-class Probody drug conjugate targeting CD71. CD71 is widely expressed on normal tissues and therefore is considered to be an undruggable target for conventional antibody-drug conjugate technology. During Q2, this program continued to enroll patients in the initial dose-escalation phase of the study, which is being run by CytomX. CX-2029 is, of course, a PDC conjugated to the payload MMAE under license from Seattle Genetics. CytomX has a responsibility to advance this program through initial cohorts expansion in select tumor types whereupon, if successful, the program will transition to AbbVie for registrational studies and ultimate commercialization. CytomX retains a certain profit split and co-commercialization rights for this asset. In parallel with the co-development of CX-2029, we have an ongoing discovery alliance with AbbVie focused on the discovery and development of additional Probody drug conjugates. Under this agreement, AbbVie recently selected a second target for advancement into pre-clinical studies triggering a $10 million payment to CytomX. I'll now turn the call over to Robin for a brief review of financial highlights from Q2.