CytomX Therapeutics, Inc.

Good day, ladies and gentlemen, and welcome to this Atomic Therapeutics third quarter 2019 financial results conference call. At this time, all participants are in a listen-only mode. As a reminder, this call may be recorded. I would now like to introduce your host for today's conference, Christopher Keenan, Vice President of Investor Relations. Chris, you may begin.

Thank you, Thea. Good afternoon, and thank you for joining us. Earlier today, we issued a press release that includes a summary of our recent progress and third quarter 2019 financial results. This press release and a recording of this call can 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, Sitomx Newly Appointed Chief Development Officer, Dr. Amy Peterson, and Sitomx Vice President of Finance, Robin Nifsent. 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 10-Q filed today. We undertake no obligation to update any forward-looking statements, whether as a result of new information, future developments, or otherwise. Thank you, Chris, and good afternoon, everyone, and thanks very much for joining us.

It's a pleasure to be here to provide an update on our progress during the third quarter. I'll begin with an overview and some recent highlights, and then I'll turn the call over to Amy to review our recent clinical advances in our CX072 program. I'll then review progress with our partner programs before turning the call over to Robin for the third quarter financial update. I'll then come back and provide some closing comments that open up the call for questions. So let me start by first introducing a new voice on today's call. Recently we announced the appointment of Dr. Amy Peterson to the new role of Chief Development Officer at Cytomix. Amy brings over 20 years of experience in oncology clinical practice and drug development, having held multiple senior roles, including Chief Medical Officer of Immuno-Oncology at Beijing, where she created and led what is today recognized as a globally relevant oncology development organization. Prior to that, Amy was Vice President of Clinical Development at Medivation, where she was responsible for developing Xtandi and Talzena in breast cancer. Amy also held a variety of leadership roles at Genentech, where she worked primarily on early stage oncology assets targeting multiple major pathways. Here at Cytomix, Amy is charged with oversight of a multidisciplinary team focused on advancing Cytomix clinical development activities and driving value creation and differentiated patient outcomes across the Cytomix portfolio. We are delighted to have Amy joining our team at this important time in our evolution. Here at Cytomix, we see a major opportunity to more effectively target therapeutic antibodies into diseased tissue, generating new classes of differentiated anticancer therapies. Our innovative approach to antibody localization into diseased tissue is called the ProBody platform. ProBodies are fully recombinant antibody prodrugs comprised of a therapeutic antibody and a mask designed to block the binding of the antibody to its target until the mask is removed. Thank you so much for joining us. and we are the first to have shown clinical proof of concept for this novel approach. Our many accomplishments in recent years have brought us to an important inflection point as we transition from a research-focused platform company into an integrated R&D organization with multiple emerging product candidates. We had a productive third quarter marked by the continued advancement of our broad portfolio of wholly owned and partnered programs. These include our wholly owned anti-PDL1 ProBody CX072, are wholly owned anti-CD166 pro-body drug conjugate CX2009, the anti-CTLA4 pro-body BMS986249 being developed in partnership with Bristol-Myers, and the CD71 pro-body drug conjugate CX2029 being developed by Cytomix in partnership with AbbVie. Let's begin with our lead clinical asset, CX072. CX072 is a probody therapeutic directed against the validated immuno-oncology target PD-L1. Our vision for CX072 is for this probody to become a differentiated foundation for combination anticancer therapies by making them safer and more effective. We have shown previously that CX072 is active as a monotherapy in multiple tumor types, and that the probody has the activity to be expected from a checkpoint inhibitor, providing the first clinical proof of concept for our unique platform. Regarding our CX072 monotherapy program, patient enrollment is now complete in the Part D expansion cohorts, studying CX072 at the dose of 10 mg per gig in multiple tumor types. Our most recent data presentation from these expansions at ASCO 2019 continued to demonstrate that CX072 functions as a checkpoint inhibitor with an encouraging efficacy and safety profile. Clinical activity was seen in multiple tumor types, including triple negative breast cancer, anal squamous cell carcinoma, and cutaneous squamous cell carcinoma. Previously presented clinical pharmacokinetic and biopsy data has shown that CX072 behaves as designed, remaining stable in circulation and demonstrating intratumoral activation at levels achieving target saturation. Taken together, these findings provide a very strong foundation for potential clinical differentiation from other PD inhibitors and for combination of CX072 with other anti-capsa agents. Thank you very much. Thank you very much. Yet it's well established that a dose response exists for ipilimumab's anti-cancer activity. In recent years, experimental regimens testing the combination of PD inhibition plus CTLA-4 inhibition have used lower and lower doses of the anti-CTLA-4 agent due to poor tolerability, some even lower, in fact, than the already low dose of 1 mg per kg every three weeks. Take, for example, the two studies by BMS, Checkmate 227 and Checkmate 9LA. Both of these studies evaluated chemotherapy versus the combination of ipi plus nevo either alone or in combination with chemotherapy in patients with previously untreated non-small cell lung cancer. Of particular note, in both of these studies, the dose of ipilimumab was one mg per kg, but instead of being administered every three weeks, it was now administered only every six weeks. AstraZeneca has also reported some recent success in non-small cell lung cancer, namely in their Poseidon trial. demonstrating superiority of the combination of tremolumab, their CTLA-4 inhibitor, when given in combination with dervalumab, their PD-L1 inhibitor, and chemotherapy versus chemotherapy alone. Notably, the dose of CTLA-4 in this study was fixed at 75 milligrams, or again, the equivalent of one mg per kick. So each of these studies represent a significant down-dosing, in fact, as much as six-fold, from the dose and schedule of the CTLA-4 inhibitor when administered as a monotherapy. Thank you very much. also offers additional potential proof of concept for our platform technology, whilst also laying a foundation for the advancement of this combination into other indications and hopefully into other potential registration studies. We look forward to providing initial data from this program in 2020. Moving on now to our second wholly-owned drug candidate, CX2009. This is a pro-body drug conjugate targeting a unique tumor antigen called CD166. conjugated to the microtubule inhibitor DM4. CD166 is the most advanced of our novel targets and is well poised to help us better understand our ability to target the untargetable. CD166 is an effective internalizer of antibodies that is expressed at high levels on most solid tumors, but is also present on most normal tissues. Having completed dose escalation and presented encouraging Phase I data earlier this year at AACR, We are currently in the dose refinement stage and anticipate announcing next steps with this program towards the end of 2019. I would now like to turn the call over to Amy to give some additional background and context on our newly launched PACE-2 study of CX072.