Mersana Therapeutics, Inc.

Good afternoon and welcome to Marsana Therapeutics' second quarter 2022 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 Jason Fredette, Senior Vice President, Investor Relations and Corporate Communications. Please proceed.

Good afternoon, everyone. Before we begin, please note that this call will contain forward-looking statements within the meaning of federal securities laws. These statements may include, but are not limited to, those relating to the company's business strategy, platform potential, clinical trial or preclinical study initiations, execution and data releases, regulatory plans and objectives, commercial opportunities, collaborations, and potential associated payments, operating expenses, and cash runways. Each of these forward-looking statements are 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 with the Securities and Exchange Commission on May 9, 2022, and in subsequent SEC filings. Our filings are available at sec.gov and on our website, mursana.com. except as required by law, we assume no obligation to update forward-looking statements publicly, even if new information becomes available in the future. With that, let me turn the call over to Anna Protopappas, our President and Chief Executive Officer.

Hello, everyone, and welcome to our conference call. Joining me today with prepared remarks are our Chief Medical Officer, Arvind Yang, and our Chief Financial Officer, Brian Descheidner. I'm also joined by a set of other members of management who will be available to answer your questions. At Mursana, we aspire to be the leader in the ADC space. And in recent months, we have made significant advances towards this vision as we approach enrollment completion in Uplift, our potential registration trial, initiated patient screening in UpNext, our potential confirmatory trial, cleared our IND with the FDA for XMT1660, cleared our IND for XMT2056, and announced that the FDA has granted orphan drug designation for this candidate in gastric cancer. And finally, as we just announced, we entered into yet another exciting strategic partnership that provides significant non-diluted capital to extend our cash runway while also allowing us to retain longer-term strategic and financial upside potential. Let me begin with this most recent accomplishment. We are excited to share the news after market today that we have entered into a global collaboration providing GSK with an exclusive option to co-develop and commercialize XMT2056, which is our first immunosynth in ADC. 2056 targets a novel epitope of HER2 and is designed to activate the innate immune system through sting signaling in both tumor resident immune cells and in tumor cells. There are several financial and strategic aspects that make this deal particularly noteworthy. First and foremost, from a financial perspective, this is a very meaningful deal for an early-stage ADC asset. We believe its magnitude serves as a recognition of our differentiated immunosymptom platform, the strengths of our preclinical data, and the transformational potential of XMP 2056. Secondly, the upfront option purchase fee of $100 million extends our runway into the first half of 2024, well beyond important inflection points. Thirdly, assuming GSK opts in, they will fund a majority of the development costs for 2056 And the deal is structured so that our cash contribution would generally be offset by development milestones and other features, all while retaining participation in the potential longer-term value of this exciting program. Brian will share some additional information on the financials in just a few minutes. We believe GSK would be an ideal partner for XMT 2056. given our shared vision for the potential of this program, their wealth of global development and commercial capabilities, and their deep experience in ADC, the I.O. space, and the STING pathway. And finally, from a strategic perspective, we view this agreement as a strong endorsement of the potential of our immunosymptom platform in XMT 2056. When coupled with the research collaboration that we formed with Janssen earlier this year, leveraging a dollar symptom platform, we believe it also reaffirms that Mursana is increasingly being viewed as a partner of choice during this momentous period in the broader ADC space. Now let's touch on the progress we have made recently in executing against our plan to position UPRI as a foundational medicine in ovarian cancer, which remains our top priority. We continue to be pleased by the pace of enrollment in Uplift, our single arm registration trial in platinum resistant ovarian cancer, and are on track to announce enrollment completion around the end of the third quarter. This would position us for a top line readout and potential BLA in this indication in 2023. Up next is our phase three clinical trial of upper immunotherapy maintenance in NAPI to be high recurrent platinum sensitive ovarian cancer. We are pleased to report that we recently initiated patient screening in this trial. And then there's upgrade, our phase one to umbrella combination trial in early-line platinum-sensitive patients. Dose escalation is underway, the first arm of the trial, which is looking at the combination of UPRI with carboplatin. These three ongoing clinical trials have the potential to demonstrate UPRI's efficacy and confirm its safety and tolerability while also generating data across a broad range of ovarian cancer settings. And beyond UPRI, We're actively diversifying our clinical pipeline in a thoughtful and strategic manner with XMT 1660 and XMT 2056, both of which recently cleared INDs. Arvind will share more information on these efforts in just a moment. In summary, this has been another very productive period for MERSANA. We made substantial progress in our uplink clinical trials and our position for the top-line data readout and potential BLA filing next year. We are advancing to exciting and highly differentiated molecules with XMT1660 and XMT2056, and we are substantially strengthening our balance sheet through the partnership with GSK. We look forward to continuing this momentum in the second half of the year as we approach what we anticipate to be a transformative 2023. With that, I will ask our Chief Medical Officer, Arvind Yang, to delve more deeply into our clinical progress and plans.