Release Date: August 13, 2024
For the complete transcript of the earnings call, please refer to the full earnings call transcript.
Positive Points
- Mersana Therapeutics Inc (MRSN, Financial) advanced dose escalation in Phase 1 clinical trials for both XMT 1660 and XMT 2056.
- The company made significant progress in collaborations, earning an $8 million milestone payment from Johnson & Johnson.
- Operating expenses were reduced significantly, contributing to a decrease in net cash used in operating activities from $61.8 million to $21.8 million year-over-year.
- The company ended the second quarter with $162.7 million in cash, cash equivalents, and marketable securities, providing a cash runway into 2026.
- Research and development expenses declined significantly, reflecting the company's portfolio reprioritization and operational efficiency improvements.
Negative Points
- Collaboration revenue decreased from $10.7 million in Q2 2023 to $2.3 million in Q2 2024, primarily due to reduced collaboration revenue from Johnson & Johnson and Merck KGA.
- General and administrative expenses, although reduced, still amounted to $10.5 million for the quarter.
- The company reported a net loss of $24.3 million for Q2 2024, although this was an improvement from the $54.3 million net loss in Q2 2023.
- Uncertainty remains regarding the maximum tolerated dose (MTD) for XMT 1660, as it has not yet been established.
- The company is still in the process of optimizing dosing schedules for XMT 1660, which could delay further clinical development.
Q & A Highlights
Q: Can you provide a qualitative measure of how patients are doing in the trial? Have you observed more or deepening responses since your last update? And are you happy with the level of grade three events you're seeing?
A: We are not giving specific details on the 1660 clinical data at this time. However, we are at 80 milligrams per meter squared, which is much higher than previous doses. While we are not discussing specifics of grade three events, we are comfortable with our ability to escalate to this dose range. Detailed information will be included in our second half data disclosure. β Martin Huber, President, Chief Executive Officer, Director.
Q: Can you discuss the progress on the biomarker front and what biomarker data we could see in the second half disclosure? Also, when and how do you plan to disclose the initial 1660 clinical data?
A: We are enrolling all comers within selected patient populations and capturing tissue for retrospective analysis of B7-H4 expression. Our initial data disclosure will provide insights into whether a biomarker will be necessary for patient selection going forward. As for the data disclosure, it could be a company event or a medical congress, but we haven't defined that yet. β Martin Huber, President, Chief Executive Officer, Director and Jason Fredette, Senior Vice President, Investor Relations.
Q: Have you already committed to the expansion portion of the 1660 study? What do you need to see before initiating the expansion?
A: The expansion cohorts are built into the existing protocol. We need to identify at least one recommended Phase two dose before moving forward into the expansion. As we have not yet defined a maximum tolerated dose (MTD), we are not ready to declare a recommended Phase two dose at this time. β Martin Huber, President, Chief Executive Officer, Director.
Q: How important do you think dosing frequency could be as a potential differentiator for 1660? And where are you in the process of figuring out the optimal exposure?
A: Our molecule has an extended half-life, allowing us to explore longer dosing schedules, which could be an advantage. We are also exploring more frequent dosing regimens to optimize efficacy and safety. We are generating data on both schedules and will include this in our second half presentation to determine the appropriate schedule. β Jason Fredette, Senior Vice President, Investor Relations.
Q: Have you observed a dose response in the every four-week dosing cohort so far? And what magnitude of increase in dose exposure might be expected with a more frequent dosing schedule?
A: We are not sharing further details on exposure-response relationships at this time. We have seen responses at doses lower than 80 milligrams, but it is premature to discuss exposure-response relationships. This will be part of the second half data disclosure. β Martin Huber, President, Chief Executive Officer, Director.
Q: How are you prioritizing enrollment towards dose escalation versus collecting more data at any given backfill cohort?
A: The protocol allows for significant flexibility in patient numbers at a given dose and tumor type. We are focusing on triple-negative breast cancer (TNBC) due to its high unmet medical need and the prevalence of B7-H4. We aim to explore the activity of our ADC in a post-topo environment, and this will be part of our second half data disclosure. β Jason Fredette, Senior Vice President, Investor Relations.
Q: Can we expect biomarker data from all patients enrolled in escalation backfill? Will it be a meaningful dataset to determine an ORR in the biomarker-positive subgroup?
A: While we aim to provide a directional answer on biomarker performance, it would be presumptuous to say we will have 100% of the data. The confidence intervals around any point estimate will be relatively wide, but we should have sufficient patients to get a directional answer on biomarker performance. β Jason Fredette, Senior Vice President, Investor Relations.
Q: Do you need to reach an MTD to declare a recommended Phase two dose and move into expansion? Is the exploration of more frequent dosing driven by observations in the clinic?
A: In a perfect world, we would define a formal MTD before picking a recommended Phase two dose. However, we may not need a formal MTD if we understand where dose-limiting toxicity becomes apparent. The exploration of more frequent dosing is driven by the need to understand whether dose-limiting toxicity is C-max or AUC related. β Jason Fredette, Senior Vice President, Investor Relations.
Q: Would you be conducting expansion cohorts with multiple frequencies running in parallel? And would recruiting 30-40 patients in each cohort at different dose levels meet FDA's requirements?
A: It is possible to take two different dose schedules forward. Most people are doing some form of randomization for dose in the current environment. Ultimately, you need data justifying the therapeutic index of your dose versus an alternative dose. This will be part of our thinking when we discuss our expansion into registration plans. β Martin Huber, President, Chief Executive Officer, Director.
Q: Can you talk about your confidence in the differential activity of 1660 in topoisomerase-experienced and resistant patients?
A: There are several hypotheses suggesting our payload might not be subject to the same resistance mechanisms as topoisomerase ADCs. Our payload is not acting on topoisomerase or DNA and is not a PGP pump substrate, which theoretically supports differential activity. β Jason Fredette, Senior Vice President, Investor Relations.
For the complete transcript of the earnings call, please refer to the full earnings call transcript.
