On May 9, 2022 Mersana Therapeutics, Inc. (NASDAQ: MRSN), a clinical-stage biopharmaceutical company focused on discovering and developing a pipeline of antibody-drug conjugates (ADCs) targeting cancers in areas of high unmet medical need, reported financial results for the first quarter ended March 31, 2022 (Press release, Mersana Therapeutics, MAY 9, 2022, View Source [SID1234613940]).

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"We believe that UpRi holds the potential to transform the treatment paradigm for patients with ovarian cancer. Our development strategy is designed to advance UpRi from platinum-resistant ovarian cancer with our potential UPLIFT data readout in 2023 into earlier lines of treatment with our UP-NEXT and UPGRADE trials," said Anna Protopapas, President and Chief Executive Officer of Mersana Therapeutics. "With a strengthened balance sheet and preparations to move XMT-1660 and XMT-2056 into the clinic in the near term, we look forward to delivering clinical data across all three of our platforms and building a leading ADC company."

Strategic Goals, Recent Developments and Anticipated Milestones

Build UpRi, a Dolaflexin ADC targeting NaPi2b, into a Foundational Medicine in Ovarian Cancer:
Presented Analysis Supporting UPLIFT Trial Dose: An analysis from nearly 100 patients in the expansion cohort of the Phase 1 Upifitamab Rilsodotin (UpRi) clinical trial based on a June 10, 2021 data cut was presented at the 2022 Society of Gynecologic Oncology (SGO) Annual Meeting on Women’s Cancer. This analysis supported the decision to select 36mg/m2 as the dose for UPLIFT, given the observed efficacy in both the evaluable and intent to treat populations, fewer adverse events (AEs) including Grade 3 or higher AEs, longer duration of treatment, and fewer discontinuations relative to the higher dose group.
Expecting to Complete Enrollment in UPLIFT Registration Trial in 3Q 2022: UPLIFT is enrolling up to 180 patients with platinum-resistant ovarian cancer, including approximately 100 patients with high NaPi2b expression. The trial’s primary endpoint will evaluate efficacy in the NaPi2b high population.
Advancing Toward Initiation of Patient Screening in UP-NEXT Trial in 2Q 2022: UP-NEXT is a Phase 3 clinical trial of UpRi as monotherapy maintenance following treatment with platinum doublets in recurrent platinum-sensitive ovarian cancer. This trial has the potential to serve as a post-approval confirmatory trial, supporting the expansion of UpRi into earlier lines of therapy.
Enrolling UPGRADE Combination Trial: UPGRADE, the company’s Phase 1/2 umbrella trial of UpRi in combination with other agents, is currently dose escalating UpRi in combination with carboplatin. Mersana expects to disclose interim data from this cohort in Q4 2022, with a primary focus on safety and tolerability. UPGRADE is intended to inform the further development of UpRi in combination with other therapies used in platinum-sensitive ovarian cancer.
Build Out Pipeline of Highly Impactful Cancer Medicines
Planning to Initiate Phase 1 Clinical Trial of XMT-1660 in Mid-2022: XMT-1660 is a B7-H4-directed Dolasynthen ADC with a precise and target-optimized drug-to-antibody ratio (DAR) of 6 and Mersana’s clinically validated DolaLock microtubule inhibitor payload with controlled bystander effect. In April, the company presented preclinical data at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting demonstrating that a single dose of XMT-1660 had anti-tumor activity in xenograft models of both triple-negative breast cancer and estrogen receptor positive breast cancer. The data presented also demonstrated that higher B7-H4 expression was associated with greater anti-tumor activity of XMT-1660, consistent with its targeted effect. In its Phase 1 clinical trial, the company expects to investigate XMT-1660 in B7-H4-expressing tumors such as breast, endometrial and ovarian cancers.
Planning to Initiate Phase 1 Clinical Trial of XMT-2056 in Mid-2022: XMT-2056, the company’s first Immunosynthen STING agonist ADC, targets a novel epitope of HER2 and is designed to offer a differentiated and complementary therapeutic approach to existing and emerging solid tumor treatments. In April, the company presented preclinical data at the AACR (Free AACR Whitepaper) Annual Meeting demonstrating that XMT-2056 had robust anti-tumor activity as a monotherapy in both high and low HER-2 expressing models. The data showed XMT-2056’s complementary mechanism of action also resulted in increased efficacy across a number of models in combination with trastuzumab, pertuzumab, anti-PD-1 and trastuzumab deruxtecan. In its Phase 1 clinical trial, the company expects to investigate XMT-2056 in HER2-expressing tumors such as breast, gastric and non-small-cell lung cancers.
Maintaining Pipeline Prioritization Discipline: Based on the lower prevalence of the NaPi2b biomarker in non-small cell lung cancer, the increasingly competitive nature of this indication and the company’s commitment to remain financially disciplined, Mersana has decided to discontinue the development of XMT-1592. Additionally, the company has decided to defer certain investments in its preclinical pipeline, including two of its earlier-stage candidates, XMT-2068 and XMT-2175.
Build Mersana with Strategic Partners:
Announced New Collaboration with Janssen: In February, the company announced a research collaboration and license agreement with Janssen Biotech, Inc. to discover novel ADCs for up to three targets by leveraging Mersana’s Dolasynthen platform and ADC expertise and Janssen’s antibodies. As part of the agreement, Mersana received a $40.0 million upfront payment and has the potential to receive more than $1.0 billion in total milestone payments and mid-single-digit to low-double-digit percentage royalties on future net sales.
First Quarter 2022 Financial Results

Net cash used in operating activities in the first quarter of 2022 was $8.0 million. Cash and cash equivalents as of March 31, 2022, were $230.1 million, compared to $177.9 million in cash and cash equivalents as of December 31, 2021. This increase reflects the receipt of the $40.0 million upfront payment from Janssen and proceeds from the sale of Mersana common stock through its at-the-market (ATM) equity offering program, partially offset by operating spend. The company expects that its available funds will be sufficient to support its operating plan commitments well into the second half of 2023.
Research and development (R&D) expenses for the first quarter of 2022 were $35.8 million, compared to $27.4 million for the same period in 2021. Included in first quarter 2022 R&D expenses was $2.9 million in non-cash stock-based compensation. The year-over-year increase in R&D expenses was primarily related to greater headcount, preparations for the clinical advancement of XMT-1660 and XMT-2056, and increased UpRi manufacturing and clinical costs.
General and administrative (G&A) expenses for the first quarter of 2022 were $12.8 million, compared to $7.2 million during the same period in 2021. Included in first quarter 2022 G&A expenses was $2.6 million in non-cash stock-based compensation. The year-over-year increase in G&A expenses was primarily related to an increase in consulting and professional fees, and increased headcount.
Net loss for the first quarter of 2022 was $47.3 million, or $0.59 per share, compared to a net loss of $34.7 million, or $0.50 per share, for the same period in 2021.
Conference Call Reminder
Mersana will host a conference call today at 8:00 a.m. ET to discuss its financial results for the first quarter of 2022 and business updates. To access the call, please dial 877-303-9226 (domestic) or 409-981-0870 (international) and provide the Conference ID 4289737. A live webcast of the presentation will be available on the Investors & Media section of the Mersana website at www.mersana.com, and a replay of the webcast will be available in the same location following the conference call for at least 90 days.