A clinical-stage **Seagen** (a company known for pioneering antibody-drug conjugates or ADCs, now part of Pfizer) developing next-generation cancer therapies.

Like a clinical-stage **Amgen** (a large biotechnology company) but singularly focused on creating targeted cancer treatments using antibody-drug conjugates.

• XMT-2056: This is an investigational HER2-targeting antibody-drug conjugate (ADC) designed to activate STING, co-developed with GSK for various HER2-expressing solid tumors.
• MRSN-003: This is an investigational B7-H4 targeting ADC in early clinical development for ovarian cancer, endometrial cancer, and other B7-H4 expressing tumors.
• MRSN-004: This is an investigational NaPi2b-targeting ADC in preclinical development, designed for the treatment of platinum-resistant ovarian cancer.

Mersana Therapeutics (MRSN) is a clinical-stage biopharmaceutical company focused on discovering and developing novel antibody-drug conjugates (ADCs) for cancer. As a company in the research and development phase, it does not currently have any commercialized products that it sells to individuals or healthcare providers.

Mersana's business model relies on potential future collaboration and licensing agreements with other pharmaceutical companies for the late-stage development and commercialization of its drug candidates or technology platform. These partners would represent its "major customers."

Historically, Mersana Therapeutics had a significant strategic collaboration agreement with GlaxoSmithKline (GSK) (NYSE: GSK; LSE: GSK). This collaboration involved the development of ADCs utilizing Mersana's Dolaflexin platform and represented a major source of revenue from a partner. However, GlaxoSmithKline terminated this collaboration agreement, effective March 2023.

As of recent information, Mersana Therapeutics does not currently have other publicly disclosed major active collaboration agreements that represent significant ongoing "customer" relationships generating substantial revenue. The company is primarily focused on advancing its wholly-owned pipeline candidates through clinical development.

• Lonza Group AG (LONN)

Martin Huber, MD President and Chief Executive Officer

Marty Huber was named President and CEO of Mersana in 2023 and has been a member of Mersana's Board of Directors since 2020. Prior to his CEO role at Mersana, he served as President, Head of R&D, and Chief Medical Officer at Xilio Therapeutics, Inc. Before Xilio, he was Chief Medical Officer at TESARO, Inc., and after TESARO's acquisition by GlaxoSmithKline plc, he served as Senior Vice President, Clinical. His earlier experience includes oncology clinical development, drug safety, and pharmacovigilance roles at Merck Research Laboratories, Schering-Plough, Hoffmann-La Roche, and Rhone-Poulenc Rorer.

Brian C. DeSchuytner Senior Vice President, Chief Operating Officer and Chief Financial Officer

Brian DeSchuytner joined Mersana in June 2019, became Chief Financial Officer in October 2021, and was named Senior Vice President, Chief Operating Officer and CFO in September 2023. Before Mersana, he served as Vice President, ZEJULA Commercial at TESARO, Inc. From 2009 to 2017, he held progressively senior roles at Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda, including Vice President, Global Marketing and Global Brand Head, where he led the global launch of ixazomib.

Mohan Bala, PhD Senior Vice President, Chief Development Officer

Mohan Bala joined Mersana in October 2021. Prior to Mersana, he was Chief Operating Officer at Constellation Pharmaceuticals and VP, Development Program Lead at TESARO. He also held senior leadership positions at Sanofi, GlaxoSmithKline, and Centocor.

Alejandra Carvajal Senior Vice President, Chief Legal Officer

Alejandra Carvajal joined Mersana in April 2021. Previously, she served as Chief Legal Officer and General Counsel of Momenta Pharmaceuticals, Inc., where she oversaw legal operations through a business restructuring and the company's successful acquisition by Johnson & Johnson.

Timothy B. Lowinger, PhD Senior Vice President, Chief Science and Technology Officer

Timothy Lowinger joined Mersana as Chief Scientific Officer in February 2008 and was appointed Chief Science and Technology Officer in August 2019. He has led all of Mersana's discovery efforts and is a co-inventor of the company's innovative ADC platforms and product candidates. Before joining Mersana, he accumulated nearly 15 years of international scientific leadership and drug discovery experience in the pharmaceutical industry.

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Mersana Therapeutics (MRSN) is focusing on several key drivers to generate future revenue growth over the next 2-3 years, primarily centered on its antibody-drug conjugate (ADC) pipeline and strategic partnerships.

1. Increased Collaboration Revenue from Existing and New Partnerships: Mersana has demonstrated growing revenue from its existing collaborations. For instance, collaboration revenue increased to $12.6 million in Q3 2024 from $7.7 million in Q3 2023, primarily due to enhanced contributions from agreements with Johnson & Johnson and Merck KGaA. In Q2 2025, collaboration revenue was $3.1 million, up from $2.3 million in Q2 2024, linked to increased revenue from Johnson & Johnson and Merck KGaA, and a significant $15 million development milestone achieved in July 2025 under its agreement with GSK for XMT-2056. Future milestone payments from these existing collaborations, which are not included in current cash runway guidance, represent a potential source of revenue growth. Mersana also continues to explore additional partnering opportunities for its proprietary ADC platforms.

2. Successful Clinical Development and Potential Commercialization of Emi-Le (XMT-1660) in Breast Cancer: Emi-Le, Mersana's lead Dolasynthen ADC candidate targeting B7-H4, is the primary focus following a strategic restructuring and reprioritization. The company is advancing Emi-Le's Phase 1 clinical trial, with initial clinical data having been anticipated by the end of 2024 and initial expansion data expected in the second half of 2025. Promising preliminary objective response rates have been observed in heavily pretreated triple-negative breast cancer (TNBC) patients, indicating its potential in an area of high unmet medical need. Successful progression through clinical trials, regulatory approval, and eventual commercialization of Emi-Le would be a significant driver of product revenue.

3. Advancement and Potential Monetization of XMT-2056 through Partnership: XMT-2056, an Immunosynthen ADC targeting a novel HER2 epitope, is currently in Phase 1 dose escalation with initial pharmacodynamic data planned for 2025. GSK holds an exclusive global license option to co-develop and commercialize XMT-2056. Positive clinical data from the ongoing trial could lead to GSK exercising its option, triggering additional payments and potential future royalties, or Mersana pursuing other partnering arrangements for this candidate, thereby generating revenue.

Share Issuance

• In June 2020, Mersana Therapeutics completed a public offering of 9,200,000 shares of common stock at $19.00 per share, generating gross proceeds of approximately $174.8 million.
• The company executed a 1-for-25 reverse stock split in July 2025 to increase its per-share market price and maintain Nasdaq listing compliance, which reduced outstanding shares from approximately 124.8 million to 5.0 million.
• Mersana's financing activities over the years, as indicated by "Issuance (Purchase) of Equity Shares" on its cash flow statements, show issuances of $230.73 million in 2024, $45.56 million in 2023, $153.29 million in 2022, $95.09 million in 2021, and $6.32 million in 2020.

Inbound Investments

• In 2022, Mersana entered into collaboration agreements that collectively provided $170 million in upfront payments.
• These collaborations included a $30 million upfront payment from Merck KGaA for an Immunosynthen research collaboration and license agreement for two targets, and a $100 million upfront option purchase fee from GlaxoSmithKline plc (GSK) for the co-development and commercialization of XMT-2056.
• Additionally, a Dolasynthen research collaboration with Janssen Biotech, Inc. for three targets provided a $40 million upfront payment.
• In July 2025, Mersana achieved a $15 million development milestone payment from its agreement with GSK for XMT-2056.

Capital Expenditures

• Mersana's capital expenditures were -$473K in 2024, -$648K in 2023, -$2.20 million in 2022, -$2.17 million in 2021, and -$132K in 2020.
• The primary focus of capital allocation in this area is on funding clinical trials, preclinical activities, and research to advance its antibody-drug conjugate (ADC) pipeline.