Mersana Therapeutics, Inc.

Good morning, and welcome to Mursana Therapeutics' third quarter 2021 conference call and webcast. Currently, all participants are in listen-only mode. There will be a question and answer session at the end of this call. I would now like to turn the call over to Sarah Carmody, Executive Director, Investor Relations and Corporate Communications. Please proceed.

Good morning. Welcome to Mursano's third quarter 2021 conference call. Earlier today, we issued a press release reviewing our third quarter financial results and business updates, which will be covered on this call. A replay of today's call will also be available on the investors and media section of our website. After our prepared remarks, we will open the call for Q&A. Before we begin, I'd like to mention that our call will contain forward-looking statements within the meaning of federal securities laws, including with respect to the company's business strategy and the design, progression, and timing of its clinical or preclinical studies, and the release of data from those studies, the ability of the single-arm uplift cohort to enable registration, the development and potential of our pipeline of innovative ADC candidates, the commercial opportunity of our product candidates, expectations regarding future clinical trial results, including with respect to the timing of the commencement and future disclosures, and the sufficiency of the company's cash on hand and funds available through its debt financing agreement with Oxford Finance and Silicon Valley Bank. Each of these forward-looking statements is subject to risks and uncertainties that could cause actual results to differ materially from those projected in such statements. These risks and uncertainties are discussed in the company's quarterly report on Form 10Q, filed on August 6, 2021, and subsequent filings, which are available at www.sec.gov and on our website at www.mursana.com. Except as required by law, the company assumes no obligation to update these forward-looking statements publicly, even if new information becomes available in the future. With that, I'll turn the call over to Anna Protopappas, Mursana's President and Chief Executive Officer.

Thank you, Sarah. Good morning and welcome to our third quarter 2021 Corporate and Financial Update Call. Joining me today with prepared remarks are Arvind Yang, our Chief Medical Officer, Tim Loinger, the Chief Science and Technology Officer, and Brian Descheidner, our Chief Financial Officer. I'm also joined by the rest of the executive team who will be available for your questions, including our newest members, Tushar Misra, our Chief Manufacturing Officer, who joined us in August, and Mohan Bala, who joined us in October to take on the newly created role of Senior VP Strategic Product Planning and Program Leadership. We continue to make significant progress towards our vision of building UPRI into a foundational medicine in ovarian cancer and advancing a diverse pipeline addressing areas of high unmet medical need. As 2021 comes to a close, let's take a step back and consider what Mursana plans to achieve over the course of next year. We expect Uplift, our single arm registration study, to be fully enrolled. We expect up next our first phase three study to be initiated and enrolling. We expect upgrade to be charting the path for upbringing combinations, and we expect to have two additional assets in the clinic, XMT1660 and XMT2056. Of note, with three innovative platforms, Dolaflexin, Dolasynthin, and Immunosynthin, a strategy for NADC innovation is supported by efficient product engines creating value now and in the future. Let me start by describing our progress in building Upray into a foundational medicine for patients in ovarian cancer. In September, we disclosed further data from almost 100 patients with ovarian cancer enrolled in the expansion cohort of the Upray Phase 1 study. This data gave us confidence in the design of Uplift our ongoing single arm registration study in platinum-resistant ovarian cancer. Specifically, we believe the robust and consistent activity seen in heavily pretreated patients, the ability to further enrich outcomes for NAPI to be high, representing about two-thirds of all patients, as well as the differentiated tolerability profile without the severe neutropenia, neuropathy, or ocular toxicity seen with other ADCs will translate into both a successful uplift registration study and a robust commercial launch. In addition to uplift, we intend to expand the opportunity for UPRI to address a broader ovarian cancer population through our up next and upgrade studies. UP-NEXT is a phase three study of UPRI monotherapy maintenance, and we believe has the potential to establish UPRI as the preferred agent for maintenance therapy in happy to be high patients in the platinum sensitive ovarian cancer setting. It's worth spending a minute going into more detail on why we believe UP-NEXT will enable a substantial additional commercial opportunity for UPRI. PARP inhibitors were approved in the U.S. as ovarian cancer maintenance agents in 2017. The three PARP inhibitors approved now have combined revenues in this setting of about $1 billion in the U.S. and about $2 billion worldwide. And yet, despite the substantial revenue figures, PARP inhibitor use is limited to only a portion of the ovarian cancer population. As Arvind will explain, with UPnext, we have the potential to address the substantial unmet needs in maintenance beyond those addressable by PARP inhibitors. Shifting gears to UPGRADE, a study evaluating the combination of UPRI with platinum followed by continuation of UPRI. This is a setting even earlier in disease than UPLIFT or UPnext. This study has the potential to generate proof-of-concept data that could lead to establishing an improved standard of care in platinum-sensitive disease. Platinum and pacotaxel, a tubulin inhibitor, is the standard of care in platinum-sensitive disease, but carries substantial toxicities and, as a result, has limited treatment duration. Replacing pacotaxel with aprine, has the potential for improved efficacy, tolerability, and treatment duration. We're following a well-proven and common theme in oncology where replacing chemotherapy with a targeted agent has led to positive impact on efficacy, tolerability, and duration of treatment with the goal of translating those improvements into greater clinical benefit and ultimately improve survival. Moving into platinum combinations by replacing pacotaxel could unlock opportunities much larger than those available to PARP inhibitors because PARP inhibitors cannot be feasibly combined with chemotherapy. Together, we believe Uplift, Upnext, and Upgrade provide the roadmap for establishing Uprete as a foundational therapy in ovarian cancer, addressing significant unmet needs. Now let me turn to UPRI in non-small cell lung adenocarcinoma. We have completed enrollment and the evaluation of UPRI in lung adenocarcinoma. We observed modest single agent activity, including confirmed objective responses, but the data did not meet our internal minimum threshold of 20% overall response rate for advancement in this continually evolving and competitive indication. For this reason, we have decided to deprioritize further clinical evaluation of OPRI in this indication. The safety profile of OPRI in lung adenocarcinoma was generally consistent with the favorable profile observed with OPRI at the 36 milligrams per meter square dose level selected for further advancement in ovarian cancer. With the completion of the evaluation of the lung adenocarcinoma cohort, We now have administered UPRI to almost 200 patients. The safety profile has remained generally consistent without the severe neutropenia, peripheral neuropathy, or ocular toxicity seen with other ADC platforms. We believe this data further support our uplift design around expanded efforts with Upnext and Upgrade to build UPRI into a foundational therapy in ovarian cancer. We are committed to deploying our capital in an efficient manner in order to advance our pipeline rapidly in the places where it has the most substantial impact on patients with unmet needs. We think focusing our resources on the broad development of apri and ovarian cancer is the right thing to do for all stakeholders. This brings me to our pipeline beyond apri. Where I will start with XMD1592 are dolazid and ADC targeting NAPI2B. Based on the observations of greater efficacy in preclinical models of lung cancer, we are continuing dose exploration to determine the recommended phase 2 dose and plan for this to continue into 2022. XMT1660 are DOLA-symptom B7H4-targeted ATC, and XMT2056 are HER2-targeted immunosynthetic agonist ATC, are advancing through IND-enabling studies. Our goal for both programs is to initiate clinical studies in early 2022. Just recently, Tim Loinger, our Chief Science and Technology Officer, presented exciting preclinical data supporting the robust efficacy, tolerability, and differentiation of XMT 2056. And Tim will provide a summary of this compelling data in a few moments. Lastly, on the corporate front, we have worked to strengthen the company's foundation through enhanced future capital flexibility and the expansion of our executive leadership team. In late October, we increased our access to capital and hence our strategic flexibility by partnering with Oxford and Silicon Valley Bank to enter into a new credit facility for up to $100 million. We have also continued to expand our executive leadership team with several key appointments, including bringing on Tushar Maestra as chief manufacturing officer upon Michael Kaufman's retirement and through the addition of Mohan Bala to the role of senior vice president of strategic product planning and program leadership. Both Tushar and Mohan have extensive experience in their respective fields, and we're excited they will be working with us to advance UPRI towards commercialization and to build our maturing pipeline of innovative ADCs with the potential to address unmet medical needs across multiple different tumors. To summarize, the past quarter has seen meaningful progress on the clinical development of UPRI as well as the pipeline, which could soon include two more clinical stage product candidates with the potential to address large unmet needs for cancer patients. With that, I will turn the call over to Arvind to further discuss the broad opportunity for UPRI with Uplift, Upnext, and Upgrade.