CytomX Therapeutics, Inc.

Good day, ladies and gentlemen, and welcome to the Sotomix Therapeutics Second Quarter 2019 Financials Conference Call. At this time, all participants are in listen-only mode. Later, we'll conduct a question-and-answer session, and instructions will follow at that time. If anyone should require assistance during the conference, please press star then zero on your touch-tone telephone. As a reminder, this call may be recorded. I would now like to introduce your host for today's conference call, Mr. Christopher Keenan, Vice President of Investment Relations. Chris, you may begin.

Thank you, Valerie. Thank you. Good afternoon and thank you for joining us. Earlier today, we issued a press release that includes a summary of our recent progress and second quarter 2019 financial results. This press release and a recording of this call could be found under the Investors in News section of our website at sitomx.com. With me today are Sitomx President, Chief Executive Officer and Chairman, Dr. Sean McCarthy, and Sitomx Vice President of Finance, Robin Nifsund. During today's 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, including our Form 10Q filed today. We undertake no obligation to update any forward-looking statements, whether as a result of new information, future developments, or otherwise. A webcast of this call will be available on the Investor Relations page at cytomX website at cytomX.com. I would now like to turn the call over to Sean.

Thanks, Chris, and good afternoon, everyone. I'm very pleased to be here with you today to briefly review cytomX's productive second quarter. At cytomX, we see a major opportunity to more effectively target therapeutic antibodies into diseased tissue, generating new classes of differentiated anti-cancer therapies as these are best-in-class molecules against validated targets Thank you for joining us. 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 levels 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 Therapeutics offer localized target binding in disease tissue while maintaining potency, reducing side effects, and enabling new targets and 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 our 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 shown clinical proof of concept for 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 continue 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, CX072 and CX2009, 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 lay out a roadmap for next steps and future disclosures. Let me start with our most advanced program, the PD-L1 targeting probody CX072. Our vision for CX072 is for this probody to become a differentiated centerpiece of combination anticancer therapy by enabling safer, more effective combinations. We have presented phase one clinical data on CX072 as monotherapy and in combination with the anti-CTLA-4 antibody, ipilimumab, to support this vision. and 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 CX072 in multiple tumor types at the dose of 10 milligrams per kilogram. Data were presented in poster form and also reviewed as part of a next-generation immunotherapy discussion session led by Dr. David Page of the Providence Cancer Center. Consistent with our previously presented Phase 1 dose escalation data, these data continue to show a favorable safety profile for CX072 when compared to conventional anti-PD-1 and PD-L1 antibodies. The efficacy profile of CX072 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 undifferentiated pleomorphic sarcoma. We expect to complete these initial expansion cohorts and decide our next steps for monotherapy CX072 in the second half of 2019. To date, our monotherapy data for CX072 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 CX072 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 lung 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 per gig of IPI every 6 weeks in the 227 study compared to the full labeled dose of 3 mg per gig every 3 weeks. Our previously reported Phase I data has shown that CX072 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 one work also established the maximum tolerated dose of the combination as 10 mg per kg of CX072 and 3 mg per 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, CX2009, 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 drugs 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. CX2009 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 CX2009 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 4 mgs per gig of CX2009 were 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. CX2009 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 these data as an encouraging start to the development of CX2009, and we're currently working to refine the dose of this agent as we advance towards the initiation of Phase II 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-CTLA-4 probody based on ipilimumab. This program is in a Phase I-II 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 II 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 CX2029, 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 cytomix. CX2029 is of course a PDC conjugated to the payload MMAE under license from Seattle Genetics. CytomX has responsibility to advance this program through initial cohort expansion in select tumor types whereupon, if successful, the program will transition to AbbVie for registrational studies and ultimate commercialization. CytomX retains certain profit split and co-commercialization rights for this asset. In parallel with the co-development of CX2029, we have an ongoing discovery alliance with AbbVie focused on the discovery and development of additional pro-body drug conjugates. Under this agreement, AbbVie recently selected a second target for advancement into preclinical studies, triggering a $10 billion payment to Cytomix. I'll now turn the call over to Robin for a brief review of financial highlights from Q2.