Mersana Therapeutics Q1 2023 Earnings Call Transcript

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May 9, 2023

There are 13 speakers on the call.

Operator

Good morning, and welcome to Mersano Therapeutics First Quarter 2023 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. Please note, this event is being recorded. I would now like to turn the call over to Jason Ferdette, Senior Vice President, Investor Relations and Corporate Communications.

Operator

Please proceed.

Speaker 1

Good morning, everyone. Before we begin, please note that this call will contain forward looking statements within the meaning of federal securities laws. These statements include, but are not limited to, those Related to the therapeutic potential of our product candidates and the potential of our platforms, business strategy, Clinical trial design, execution and data releases, regulatory plans and objectives, commercial opportunities, collaborations and potential associated payments, Operating expenses and cash runway. 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 our annual report on Form 10 ks filed with the Securities and Exchange Commission on February 28, 2023 and in subsequent SEC filings.

Speaker 1

Our filings are available at sec.gov and on our website, mersana.com. Except as required by law, we assume no obligation to update forward looking statements So with that, let me turn the call over to Anna Protopapas, our President and Chief Executive Officer.

Speaker 2

Thank you, Jason, and hello, everyone. Welcome to our conference call. Joining me today with prepared remarks are Mersana's Chief Medical Officer, Arvind Yang and Chief Financial Officer, Brian De Scheitner. We also have other members of management here who will be available to answer your questions. 2023 is shaping up to be a potentially transformational year for VERSADA.

Speaker 2

We are on the verge of a top line data readout for a first in class ADC, Apri, while we also execute on a comprehensive Clinical development plans for this candidate with the potential to address significant unmet medical needs for patients suffering from ovarian We are advancing our own pipeline and are also collaborating with several other organizations utilizing our 3 proprietary ADC platforms. And thanks in a large part to the successes we've had on the business development front, We are doing all of this on a strong financial footing. We are pursuing our objectives during a historic period for ADCs, As evidenced by numerous new collaborations, additional approvals, exciting new data presentations And one of the largest biotech acquisitions to date. In platinum resistant ovarian cancer specifically, Rubituximab just recently reaffirmed the single arm accelerated approval pathway. And from a commercial perspective, The early uptake of testing and treatment for this product has demonstrated both the high unmet medical need in platinum resistant ovarian cancer And the willingness of treating physicians to appraise a targeted approach to therapy.

Speaker 2

And so we're in the midst of a very exciting period. Thanks to a decade of hard work by the team here at Mersana, The innovative approach that we have taken to ATC platform development and our advanced stage of clinical development with Apri, We believe we're well positioned to add to the momentum in the field. We are putting a heavy emphasis on our strategy We established our 3 years of foundational medicine in ovarian cancer as we advance 3 ongoing clinical trials Let's seek to address areas of high unmet medical need. The first is Uplift, our single arm registration trial in platinum resistant ovarian cancer as evidenced by our rapid enrollment of approximately 270 patients in this And recent product uptake in the platinum resistance space, the unmet medical need for these late stage patients is very Up next is our Phase III clinical trial of UPREIT as a monotherapy maintenance treatment In recurrent platinum sensitive ovarian cancer, this trial is designed to serve as a post approval confirmatory trial of Aprix in the U. S.

Speaker 2

Significantly increase our potential market opportunity by supporting expansion into earlier lines of therapy and support potential approvals outside the event. And then there is UPGRADE A, Our Phase I combination trial of Aprene with carboplatin in platinum sensitive ovarian cancer. We hope this data will inform our path to earlier lines of treatment. With top line data from Uplift Planned for mid year after the upcoming oncology conferences in June and a potential DNA submission around the end of this year, We have begun to prepare for potential commercialization. For instance, we have formed a small core team And we're working diligently to ensure we can hit the ground running with NaPi2B testing.

Speaker 2

Beyond our pre, we continue to make progress in our Phase 1 trial of XMT 1660, our B7H4 $4 symptom product candidate and are working to address the clinical hold the FDA recently placed on our Phase I clinical trial of XMP-two thousand and fifty six. To further discuss our clinical plans and progress, I'll turn the call over to Arvind. Thank you, Anna.

Speaker 3

Let's begin by discussing Aptlyft. Platinum resistant ovarian cancer remains an area of significant unmet medical need. Patients at this most advanced stage of are heavily pretreated and have a very poor prognosis. For most patients, treatment options are limited to single agent chemotherapy, which has consistently demonstrated an objective response rate of approximately 12% in previous trials. We're seeking to fill this significant gap Following the release of data from Mirasol and based on mirvetuximab's label, It is worth noting several key differences in our trial populations.

Speaker 3

In Uplift, we enrolled an all commerce population and retrospectively are determining NaPi2b positive status as compared to Mirasol, which preselected for folate receptor alpha positive patients. We believe that at least a majority of ovarian cancer patients have NaPi2b positive expression. In fact, The large SNAP B2B data set that has been presented to date assessing roughly 400 unique tissue samples suggests that 59% of ovarian cancer patients are NaPi2b positive. In contrast, available data suggests that only a minority We also enrolled patients in Uplift Who have received 1 to 4 prior lines of therapy compared to both Soraya and Mirasol, which enrolled patients who had received 1 to 3 prior lines. We believe the differences observed between psoriasis and Mirasol serve as a reminder how ORR can be influenced by the type and level of patient pretreatment.

Speaker 3

We also enrolled patients with Grade 2 underlying neuropathy in Uplift, while these patients were excluded from both Suraya and Mirasol. Our broad inclusion criteria were based largely on the encouraging data from our dose expansion cohort. Uplift's primary endpoint is the investigator assessed objective response rate or ORR in the NaPi2b positive population. The primary endpoint will aim to exclude the 12% objective response rate for single agent chemotherapy from the 95% confidence interval. In addition to ORR, we expect the FDA to evaluate duration of response or DOR along with safety and tolerability in the overall context of the Uplift data.

Speaker 3

In addition to Uplift, we are continuing to enroll patients in our Phase 3 UP NEXT trial. There is a substantial need For new ovarian cancer maintenance treatments as many patients have already exhausted available maintenance options by the time they have recurrent disease. And with the recent label restrictions related to PARP inhibitors, this need is only getting larger. UPNEXT is enrolling 350 patients. These patients must be nappy to be positive and they must have achieved stable disease or better in response to their prior induction chemotherapy.

Speaker 3

In recognition of the lack of standard of care and the recurrent maintenance, the trial is randomizing patients 2 to 1 to receive UPRE or placebo. Our primary endpoint for the trial is progression free survival or PFS by blinded independent central review. Our 3rd ongoing UPREIT trial, UPREIT A, is evaluating UPREIT in combination with carboplatinum. Historically, the combination of carboplatinum and paclitaxel has served as the standard of care in earlier lines of ovarian cancer treatment. However, distinct tolerability challenges, including high rates of severe neutropenia, peripheral neuropathy and alopecia Have limited the ability to dose this combination beyond 6 cycles.

Speaker 3

In upgrade A, patients receive UprE in combination with carboplatinum for up 6 cycles as an induction treatment and UPREASE then continued as a monthly maintenance monotherapy. We believe the differentiated tolerability profile we observed for UPREIT in our monotherapy dose expansion trial without toxicities commonly seen with other ADC platforms We position it well for use in combinations. We were pleased to complete dose escalation in upgrade A and move into dose expansion in the Q1. And we're looking forward to sharing initial interim data in the second half of this year. Before delving into our other clinical stage Cytotoxic ADC, XMT-sixteen sixty.

Speaker 3

Let's touch on XMT-two thousand and fifty six, which is our HER2 directed immunosympan STING agonist In March, we voluntarily suspended our Phase 1 trial of this product candidate following a Grade 5 serious adverse event or SAE that was deemed to be related to XMT-two thousand and fifty six. The FDA then placed the trial on clinical hold. The SAE occurred in the 2nd patient enrolled at the initial dose level in the dose escalation portion of the trial and it was obviously quite unfortunate and unexpected. In recent weeks, we've received plasma PK and cytokine data for the 2 patients who are dosed in the trial prior to the clinical hold and we're continuing to analyze these data. We're evaluating next steps for the program and we'll prepare our response to the FDA's clinical hold letter.

Speaker 3

We will provide an update on our plans once they've been solidified. Now let's turn to XMT 1660, Our Dolasynthen product candidate targeting B7H4. We see B7H4 as a particularly compelling target, Given its high expression in a variety of tumors and its limited expression in healthy tissue, XFT-sixteen sixty is equipped with a precise target optimized drug to antibody ratio of 6 and our dolaloc payload with controlled bystander effect. I'm happy to report that we are making good progress in the dose escalation portion of our multicenter Phase 1 trial, which is enrolling patients with breast, endometrial and ovarian cancers and remain firmly on track to complete this portion of the trial later this year. With that, let's turn the call over to our Chief Financial Officer, Brian DeSteitner for an update on our financials.

Speaker 3

Brian?

Speaker 4

Thank you, Arvind. We are approaching our upcoming top line data readout in a strong financial position. Beyond the $170,000,000 upfront payments we received from collaborations over the past year, we're beginning to see the downstream benefit of those transactions in the form of initial Discovery milestone revenues. We ended the Q1 with approximately $274,000,000 in cash, cash equivalents and marketable securities, and we also have a line of credit available to us. We expect our available funds to support our operating plan commitments into the second half of twenty twenty four, while past several potential milestones of significance.

Speaker 4

It should also be noted that our cash runway guidance does not assume Any potential milestone payments from our current collaborations or proceeds that we may realize from future collaborations. Now for a brief recap of our P and L for the Q1. Net cash used in operating activities was approximately $29,000,000 for the Q1 of 20 Collaboration revenue for the Q1 of 2023 was $7,800,000 compared to $2,000,000 for the same period in 2022. The year over year increase was primarily related to our collaboration agreements with Merck KGaA and Assata. Research and development expenses for the Q1 of 2023 were $47,300,000 compared to $35,800,000 for the same period in 2022.

Speaker 4

Non cash R and D related stock based compensation expense for the Q1 of 2023 was $3,300,000 The year over year increase in R and D expenses was primarily related to higher manufacturing and clinical costs related to Opry and an increase in headcount. General and administrative expenses for the Q1 of 2023 were $18,300,000 compared to $12,800,000 during the same period in 2022. Non cash G and A related stock based compensation expense for the Q1 of 2023 was $3,100,000 The year over year increase in G and A expenses was primarily related to increases in medical affairs and pre commercial activities at headcount. Mersada's net loss for the Q1 of 2023 was $56,200,000 compared to a net loss of $47,300,000 for the same period in 2022. Now I'll turn the call back over to Anna for a few closing remarks.

Speaker 2

Thanks, Brian and our friend. In summary, 2023 is lining up to be a transformative year to Mersana, and we're excited by all that lies ahead. We expect to report top line data for Uplift midyear following the major oncology conferences in June With a potential BLA submission plan for around the end of the year, we plan to significantly advance enrollment In our confirmatory trial up next, we will also advance the dose expansion portion of upgrade A and expect to report initial interim data from this trial in the second half of the year. Our team will continue to work to evaluate next steps related to our development of XMT 2056. And finally, We plan to complete the dose escalation portion of our Phase I trial of XMT-sixteen sixty this year.

Speaker 2

We look forward to keeping you updated on all our progress. Now let's open the call to your questions. Operator, would you please provide the instructions?

Operator

Thank you. We will now begin the question and answer session.

Speaker 5

Maybe just one on ASCO. Heading into ASCO, we saw that you have a presentation there on expression of Folate receptor alpha and also NaPi2b. So Can you shed some light on what that presentation entail and what should we be looking for there? And then I have a follow-up. Thank you.

Speaker 3

This is Arvind. I can address that question. So we look forward to sharing information at ASCO and it's a data set that comes from our expansion cohort Of our UPRE study, the Phase 1 study and really the purpose of it is to evaluate NaPi2b expression and O8 receptor alpha expression, recognizing that in other datasets external to the one that we're presenting, we've described how NaPi2b is approximately 59% based on 400 tumor samples relative to what we've seen from the FDA review of on rivituximab where 29% was the positivity for folate receptor alpha.

Speaker 5

Great. And maybe just one on Uplift top line. Heading into Uplift top line later this year, later mid year, Outside of overall response rate and duration of response, are there any additional efficacy measures that we could get at the top of the top line?

Speaker 2

So I think as we've said, the top line will be midyear after the June oncology conferences and we will be showing overall response rate in the primary endpoint as well as the secondary endpoint,

Speaker 5

Thanks, Anna. Thank you.

Operator

Thank you. And our next question today comes from Jonathan Chang with CB Securities, please go ahead.

Speaker 6

Good morning. Thanks for taking my questions. First question, On the recent Mirasol results, how does that impact your thinking on the UPRE opportunity and strategy?

Speaker 2

We remain very excited about the Apria opportunity, Jonathan. As you know, and this is Evident from what we've seen from ImmunoGen, this is an area of high unmet medical need. There's a desperate

Speaker 6

need by physicians and patients for

Speaker 2

new agents, and we Spread lead by physicians and patients for new agents and we remain very excited about Apri. We've shown robust efficacy And a differentiated tolerability profile in the expansion cohort. And of course, as Arvind just alluded to, We have an agent that has a very significantly different prevalence and the overlap between Folate High And NaPi-2b high is quite limited. So there's a desperate need for new agents for these patients and we hope UPREIT will fill that

Speaker 6

Got it. Thank you. And second question, when could we see initial data from the B7

Speaker 2

What we've guided to and I think as we mentioned on the call is that we expect to complete dose By the end of this year, our dose escalation is proceeding as planned. And at that point, I think we have not yet guided to data disclosures. But we're very excited about the program. We think this is a great target for an ADC and for our platform. So we'll make that decision on data disclosure as we approach completion of the doses donation.

Speaker 6

Got it. Thanks for taking my questions.

Operator

Thank you. And our next question today comes from Collyn Cusi with Baird. Please go ahead.

Speaker 7

Hi, good morning and thanks for taking our questions. On the Uplift readout that's coming up in mid year, Would you expect to also report data in the overall patient population? And do you have any expectations on what you'd need to show in the NaPi2b Low patient population to get a broad label?

Speaker 3

Sure. Thanks, Colleen. So, we do expect to share data not only in the NaPi2b positive Population, which is our primary endpoint, but the overall population is a key secondary endpoint. So response rate in the key secondary endpoint Could also support a broader indication. This alludes to actually your second question in relationship to what would you need to see in the low population.

Speaker 3

So keeping in mind that the benchmark for approval for both of these populations in discussion with FDA really is Single agent chemotherapy response rates of 12%. Now that being said, the response rate in the overall population, We would imagine could not be completely driven by the NaPi2b positive population in order to generate that overall population response rate.

Speaker 7

Got it. That's helpful. Thank you. And then on the upgrade data later this year, are you able to say Roughly how many patients you'd expect and how much follow-up you'd expect to have?

Speaker 3

So, We had announced last year that we had completed our with that we had approximately 12 patients Within the dose escalation portion. And then in the Q1 of this year, we had indicated that we had completed dose escalation And initiated the expansion phase. So you can approximate in relationship to how many patients we would have within dose escalation. And a determination will be made just in relationship to how many patients would then be available for presentation in the second half This year. That also gives you some sense of the follow-up that would be available for those patients.

Speaker 7

Got it. That's helpful. Thank you. And then just last follow-up on the upgrade study that's reading out later. So would The focus there be mainly on safety or can you kind of help us set a bar for efficacy in that readout?

Speaker 3

Sure. So the primary focus absolutely is safety. It's a Phase 1 study and it is really driven off the premise that UPREIT provides a differentiated profile, with non overlapping toxicities affording it a great opportunity to combine with standard of care Platinum, for instance. In addition to that, obviously being able to continue the UPREIT portion of it after completion of the 6 cycles of combination, into the monotherapy. So safety will be the primary focus of this presentation, recognizing that the Follow-up to get into the maintenance may not be sufficient at that time point.

Speaker 3

We will plan to present also efficacy for the available information, But it's in the context, obviously, of recognizing safety as the primary focus.

Speaker 7

Great. Thanks for taking our questions.

Operator

Thank you. Our next question today comes from Kaveri Pullman with BTIG. Please go ahead.

Speaker 8

Yes. Good morning. Thanks for the update and for taking my questions. For the upcoming ASCO data for expression studies, is that specifically for platinum resistant population? Do you expect to see any changes in NaPi-2b expression or the overlap when you move to earlier lines?

Speaker 3

Thanks for the question, Kavari. So, just for context, obviously, we want to share the presentation for ASCO. But as I mentioned earlier, this will be on a data set that comes from our Phase 1 study. And so that included Primarily platinum resistant ovarian cancer patients. There was a proportion of patients that were 4th line plus that could have been platinum sensitive.

Speaker 3

But again, these But to your second point in relationship to the prevalence of NaPi2b, We shared actually a variety of different presentations in the past from tumor banks, from our own internal studies that support There I'll remind folks that 59% was the NaPi2b positivity when looking at 1 of the largest the largest Tumor bank analysis of individual tissue samples of approximately 400 samples.

Speaker 8

That's very helpful. Thank you. And for the UPNEXT study, it's a novel design, but any insight You could provide on addressable patient population, how different it is from the platinum resistant market? And in terms of Benchmarks for PFS, what would you expect out of the placebo arm?

Speaker 2

So maybe Arvind can talk to the placebo arm and the protection benefit here. As for The size of the market, we have not given specific numbers, but we do believe that this trial will bring us to a large Unmet medical need, potentially larger than platinum resistant with a positive UPNEXT trial.

Speaker 3

And maybe just before I jump into the placebo effect, I'll just comment that given the emerging landscape of the PARP inhibitors, With the recent FDA changes, where PARP inhibitors are no longer approved in the Or restricted primarily to the BRCA and the HRD positives. We see that actually as increasing the unmet need in that recurrent platinum maintenance setting, Item sensitive maintenance setting. Correct, just to your second question as far as the activity of placebo, One of the best benchmarks, maybe the NOVA study. So it's a study of a PARP inhibitor in the recurrent platinum sensitive maintenance setting. And there the placebo arm had a performance of PFS of approximately 4.5 months.

Speaker 3

But I do want to provide context to that figure because That was a study performed in an earlier time period where patients may not have received or would not have actually received prior part per bev in that era where the study was conducted. In addition to that, this patient population was less heavily pretreated and That's refractory because they did not include stable disease patients to the prior platinum therapy, in acknowledgment that the PARP inhibitor and platinum Mechanism of action has sufficient similarity that they did not want to include stable disease patients for their study as opposed to in up next When we do include these patients.

Speaker 8

Got it. And maybe the last one on B7 H4 ADC. From the competitive landscape standpoint and from your experience with Apri and 1529, Can you tell us what advantages the single species ADCs provide?

Speaker 2

We didn't hear the second part of your question. You're asking for the differentiation versus other B7 For APCs, Cabari, was that the question?

Speaker 8

Yes. And you have intensive experience with UHPRI and 1529, which was also a single species ADC. So I just wanted to get some sense what advantages these homogeneous The ADC provides.

Speaker 3

Sure. I can start and if the team wants to add to that. So I mean, first off, We're very excited about B7H4. We think it's a good target. Given the competitive landscape, I would argue that others agree with us in relationship Before diving into that, actually, let me just clarify.

Speaker 3

We do actually have extensive knowledge with The Dolaflexin molecule and its differentiated safety profile given that it's the same payload that's utilized in Opry, Again, without the severe neutropenias, the ocular toxicities or the neuropathies. We did evaluate it also In the 1592 program, I just wanted to clarify that that was a dolacinthin molecule with the same payload. Just to clarify, it wasn't 1529. Now with that being said, we are excited about B7H4 because It does differentiate relative to and I'll flag 2 different companies that are also developing B7H4. So Seagen It's developing a B7H molecule, but we have a DARA of a homogeneous DARA of 6 alluding to sort of the point you're raising.

Speaker 3

And we believe that through our preclinical data that the DARA-six did have differential benefit from the standpoint of greater

Speaker 6

efficacy when looking at

Speaker 3

our preclinical models. When looking at our preclinical models, in addition to that, we do expect that from a pillar perspective, it will have that differentiated safety profile relative to The MMAE that the C Gen molecule is being developed at, where they also have a lower DAR of approximately 3.5. So I think that addresses your question just as far as the differentiated profile.

Speaker 8

Yes, that's very helpful. And yes, I meant 92 instead of 29. Sorry about that.

Speaker 3

No problem.

Operator

And our next question today comes from Ashik Mahbharat with Citi. Please go ahead.

Speaker 9

Hi, team. Thanks for taking my questions. I know you made some comments related to building out the commercial infrastructure in the past quarter. Can you comment at all on the size and the reach of the sales force for Upray you're building out? And maybe any general commentary on how much of an educational uplift You think there needs to be with the NaPi2b biomarker testing in the sort of real world setting?

Speaker 2

So our commercial efforts are very much focused on pre launch activities. We're some ways away from really defining The exact size and details of the sales force. So let me focus on what we are doing now. We have a very small but And Paxful Medical Affairs Group that is really working with investigators to increase the awareness of the importance of NaPi to be as a biomarker and to educate on UPREIT as a potential therapy In ovarian cancer, we have really a handful of people with deep ovarian cancer commercial expertise That are really preparing the market plans and ensuring that our diagnostic is available on day 1. So that is the effort.

Speaker 2

A very small group of people has, I believe, been very impactful in ensuring all the work is done For us to be ready with positive data with a BLA and then our potentially an upcoming approval To be able to build out that effort.

Speaker 9

Got it. That's really helpful. I can ask one more also on the commercial plan. I think in the past you've alluded to your plan to partner Apri in Europe and in other regions globally. And I'm just wondering if you can remind us why that's I think ImmunoGen made some commentary last week related to the idea that the European market is actually pretty concentrated around A limited number of centers, which cover maybe covers the majority of the market.

Speaker 9

So I'm wondering why you if you think are thinking about the European In a similar or very different way given you're planning to partner.

Speaker 2

Yes. Our thoughts are really based on Extensive experience across the biotech industry, really investing in an infrastructure in Europe, Although eventually might be might pay off, it's a significant investment. And as you're aware, Getting reimbursement in Europe always takes time. So, by the time that European infrastructure becomes cash flow positive takes a lot longer to get there than in the U. S.

Speaker 2

And I think that's what's driving our thinking, which of course will be refined As we get top line data, we'll be further refined. But I think history will say that Small biotech companies that expand to both the U. S. And Europe can would require significant investment before that Commercial infrastructure can really begin to be cash flow positive.

Speaker 9

Got it. Thanks for taking my questions.

Operator

Thank you. And our next question today comes from Boris Peaker with Cowen. Please go ahead.

Speaker 5

Great. Thanks for

Speaker 10

With the FDA, what the agency may be looking for in terms of duration of response?

Speaker 3

Thanks for the question, Boris. So In discussions with FDA, we've aligned that response rates is the primary endpoint for evaluation of efficacy and That's 12% based upon the multiple Phase 3 studies that we've described in the past. Duration of response certainly will be It will be in the context again of the overall efficacy and safety profile, that it will be taken into context.

Speaker 10

Great. And maybe in terms of baseline characteristic, you mentioned that you allowed baseline grade 2, I guess, lower neuropathy in the Uplift trial, While these patients were excluded from SORAYA and Mirasol, just curious, can you comment what fraction of these platinum refractory patients have this baseline neuropathy?

Speaker 3

I don't have the numbers specifically for the expansion data available in reference to that. But based on what I just described earlier is that We do expect a fair proportion of patients to have some degree of neuropathy that could obviously be impacted if they were to receive Further therapy that could cause neuropathy whereby with Upright, we have not seen the severe neuropathies.

Speaker 10

Great. Thank you very much for taking my questions.

Operator

Thank you. And our next question comes from Asthika Goonewardeneck with Truist. Please go ahead.

Speaker 11

Hi, guys. Good morning. Thanks for taking the questions. So The MIRRORSOL study, the ORR surprised us positively getting to the 40% plus range. And I guess one could attribute that To being at the site recruiting a more homogeneous population than the Phase 1s and can see a less sicker patient population than psoriasis.

Speaker 11

You guys have already hit a very high bar with ORR in your Phase 1 expansion work. So would it be unreasonable to expect your ORR to look

Speaker 2

Well, thanks for the question. We saw robust activity in the expansion cohort, particularly with the 36 milligram per meter squared. But I think The differences in overall response rate between Mirasol and Psoraya do serve as a reminder that the Type and level of patient pretreatment can influence impact. And again, as Arvind mentioned on the call, We do have a population that is more heavily pretreated than psoriasis and definitely Even more heavily pretreated than Mirasol. So I think, we'll have to wait and see, the results midyear.

Speaker 2

But we will configure based on the robust activity we saw in the expansion cohort.

Speaker 11

Great. Thanks, guys. And then maybe just a quick 2 quick questions. Do you plan to report the upgrade A data at a medical meeting or would that be more geared towards the investment community? And then on the diagnostic test, Our KOL checks suggested that there were some bottlenecks faced With the diagnostic test for motuximab, with one of the centers in particular Take a little bit of a while to turn the test around.

Speaker 11

What have you learned from that from your competitive experience and what are you doing to kind of Make sure that you don't answer the same issues. Thanks.

Speaker 2

On the diagnostic, we're working with our diagnostic partner We ensure that the test is available on day 1 and that we appropriately prepare in terms of Supply of reagents to ensure there is no disruption in availability of the test. And what was the other question? Was there a second question?

Speaker 3

Yes, I can address the first question. Just as far as upgrade A, we've indicated that we'll share the

Speaker 6

data in

Speaker 3

the We haven't expressed sort of what type of forum that will be in and we'll disclose at the appropriate time.

Operator

Question today comes from David Nierengarten with Wedbush Securities. Please go ahead.

Speaker 12

Hey, maybe as a follow-up on the Diagnostic or the testing question is just if you had any particularly updated thoughts on how Physicians would, when presented with a patient in an earlier lines or I guess in any line setting, You'll react to the patients, should they test with folate first? Are they going to do both tests, do you think? Kind of how And treat appropriately, kind of how do you see that evolving with positive Mirasol results? Thanks.

Speaker 2

We are very encouraged by the testing that is taking place with falling positive patients. And we believe that what will happen once both agents are in the market is that when a patient is diagnosed with ovarian cancer, They will undergo a set of tests that will include both folate and NaPi2b and that is the desired We have a very clear sort of state of affairs in the future, and I think the uptake we've seen on the following test It's encouraging that that will be the case.

Speaker 12

Got it.

Speaker 2

And David, we are definitely working to make sure that our test is available on day 1 after launch For anyone at any stage who wants to take the test at any stage of their disease.

Speaker 12

Yes. Great. Thank you.

Operator

Our next question is a follow-up from Collyn Cusick with Baird. Please go ahead.

Speaker 7

Hi, good morning again. Thanks for taking the follow-up. Just one more. So on the Uplift readout and kind of understanding that the Patient pretreatment is going to impact the ORR. Can you remind us how many patients in the dose expansion were 4th line or later?

Speaker 7

Would you expect that proportion of patients to be similar or different in the OPLIFT study?

Speaker 3

Thanks for the question, Colleen. So approximately 33 Percent of the patients in the expansion portion of the Phase 1 study for UPRI was fourth line or later. Obviously, we'll disclose the broader demographics at the top line per se. But for context, we Enrolled in the U. S.

Speaker 3

As well as in the EU for the Uplift study globally in relation to the Uplift study, but We would expect practice tenants to be relatively similar in the platinum resistant space.

Speaker 2

Puneet, I would add one other point. The fact that we have enrolled so robustly in Uplift, I think, might give us an opportunity to look at High pretreatment impacts overall response in subgroup analysis, and really help us better understand, the profile

Speaker 7

Great. Thank you.

Operator

And ladies and gentlemen, this concludes our question and answer session. I'd like to turn the conference back over to Anna Frohnopappas for any closing remarks.

Speaker 2

Thank you, operator, and thanks to all those who listened in Sharing several poster presentations at ASCO next month and presenting at the Jefferies Healthcare Conference a few days later.

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