May 10, 2021
Operator
Good morning, and welcome to the ImmunoGen's First Quarter of 2021 Financial and Operating Results Conference Call. Today's conference is being recorded.
At this time, I'd like to turn the call over to Courtney O'Konek, Senior Director of Corporate Communications and Investor Relations. Ma'am, please go ahead.
Courtney O'Konek
Good morning, and thank you for joining today's call. Earlier today, we issued a press release that includes a summary of our recent progress in first quarter 2021 financial results.
This press release and a recording of this call can be found under the Investors & Media section of our website at immunogen.com. With me today are Mark Enyedy, our President and CEO; Anna Berkenblit, our Chief Medical Officer; and Susan Altschuller, our CFO.
During today's call, we will review key accomplishments for the business over the last three months, our financial results and anticipated upcoming events. During the discussion, we will use forward-looking statements, and our actual results may differ materially from such statements.
Descriptions of the risks and uncertainties associated with an investment in ImmunoGen are included in our SEC filings. And with that, I'll turn the call over to Mark.
Mark Enyedy
Thanks, Courtney. Good morning, everyone, and thank you for joining us today.
I'll begin with our lead program, mirvetuximab. We recently completed enrollment in SORAYA, which is our pivotal single-arm study in platinum-resistant disease, which has shifted the anticipated timing of top line data from the third into the fourth quarter of this year and the projected submission of the BLA into the first quarter of 2022.
We've also experienced some COVID-related impact on accrual for our confirmatory MIRASOL trial and correspondingly now expect the readout on the primary endpoint to move from the second to the third quarter of 2022. And I will provide some more color around the updated timelines in a moment.
Importantly, with positive results from these studies, we continue to anticipate potential accelerated approval of mirvetuximab in 2022 and full approval in 2023. Beyond platinum-resistant ovarian cancer, we submitted a protocol for a single-arm study of mirvetuximab monotherapy in recurrent platinum-sensitive disease and anticipate initiating patient enrollment for this cohort in the second half of this year.
This study further expands our approach to displacing single-agent chemotherapy in later lines of treatment in ovarian cancer. Turning to mirvetuximab in combinations.
We were pleased to learn that mature data from our Phase 1b FORWARD II doublet of mirvetuximab plus avastin in patients with platinum-agnostic disease were accepted for an oral presentation at ASCO this year. In addition, a 70-patient IST led by Dr.
Rebecca Arend at UAB is now under way, evaluating mirvetuximab in combination with carboplatin in the neoadjuvant setting. Finally, we're supporting a randomized study comparing mirvetuximab combined with carboplatin to standard-of-care in patients with recurrent platinum-sensitive disease in a large IST led by Philip Harter in the AGO in Germany with patient enrollment expected to start in the second half of this year.
We continue to advance our second pivotal program, IMGN632 in CD123 positive hematologic malignancies. Having established a path to full approval in BPDCN, we are progressing our Phase I expansion cohort in frontline patients and expect to generate top line data in the first half of 2022 with potential approval next year.
We are also advancing 632 in combination studies with azacitidine and venetoclax in relapsed and refractory in frontline AML patients and look forward to presenting data from these combinations at ASH in December. Moving to our earlier-stage pipeline.
We presented preclinical data at AACR for our first-in-class ADAM9 targeting ADC, IMGC936, which we are codeveloping with MacroGenics. We also continued IND-enabling activities for our next-generation folate receptor alpha targeting ADC, IMGN151 and expect to submit an application by year-end.
2021 and 2022 are critical years in ImmunoGen's evolution as we prepare to bring two products to the market and further our innovative portfolio of transformative ADCs for solid tumors and hematologic malignancies. We look forward to keeping you apprised of our progress as we generate clinical data and prepare for commercialization.
And with that, I'll turn the call over to Anna to provide some additional color on our clinical programs. Anna?
Anna Berkenblit
Thanks Mark. I'll start with SORAYA.
While we have recently fully enrolled the study, accrual was more variable relative to our prior experience due to a combination of factors, including COVID-19 as well as screening activity in some trials tapering in recent weeks as they anticipated imminent completion of enrollment. These factors contributed to a roughly six-week delay, which, as Mark mentioned, has shifted the timing for reporting top line data for SORAYA into the fourth quarter.
The net effect has also moved our planned submission of the BLA into the first quarter of 2022. Despite MIRASOL having had an earlier start, COVID-19 has also affected site activation and patient accrual in this trial.
While we initially expected top line data in the latter part of the first half of 2022, we now expect top line data in the third quarter of 2022 with the submission of the supplemental BLA for full approval planned by the end of 2022. Completing the SORAYA and MIRASOL studies are the highest priority for the business, and we look forward to the opportunity to offer a new therapeutic option to patients living with ovarian cancer.
With the continued uptake of PARP inhibitors as maintenance in the frontline and recurrent platinum-sensitive setting, there is an increasing population of ovarian cancer patients for whom a non-platinum based regimen is needed. The initial data we have for mirvetuximab monotherapy in heavily pretreated platinum-sensitive patients are encouraging, and we have, therefore, submitted a protocol to the FDA for a single-arm trial in this population.
Operational activities are under way to enable initiation of the study in the second half of this year. To expand into earlier lines of ovarian cancer treatment, we are pursuing combination studies with carboplatin.
An investigator-sponsored trial in the neoadjuvant setting is now under way at the University of Alabama with Dr. Rebecca Arend.
This is our first opportunity to assess mirvetuximab in the upfront setting. Importantly, this trial will support our goal of incorporating folate receptor alpha testing at diagnosis as part of standard-of-care.
In addition to this trial, we are also supporting a randomized study comparing mirvetuximab in combination with carboplatin to standard-of-care in recurrent platinum-sensitive disease with Dr. Phillip Harter in Germany.
This trial is slated to start in the second half of the year. In addition to starting these new trials in combination with carboplatin, we are pleased to have mature data from our mirvetuximab plus avastin cohort in recurrent ovarian cancer regardless of platinum status selected for a virtual oral presentation at ASCO in June.
Dr. Dave O'Malley from the Ohio State University will present mature safety and efficacy data from our Phase 1b FORWARD II cohort of mirvetuximab plus avastin, which we believe will bring us a step closer to achieving our goal of establishing mirvetuximab as the combination agent of choice in ovarian cancer and supporting its use in earlier lines of therapy.
In addition, two posters from our collaborators were accepted for presentation at ASCO. Data from an expansion cohort from the city of HOPE trial evaluating mirvetuximab in combination with gemcitabine in patients with folate receptor alpha positive platinum-resistant ovarian cancer and a trial in progress poster from Dana Farber, evaluating mirvetuximab in combination with pembrolizumab in patients with advanced or recurrent microsatellite stable endometrial cancer.
Moving to IMGC936, our ADAM9 targeted ADC. Our partners at MacroGenics identified ADAM9, a known member of the matrix metalloproteinase disintegrate family as an attractive target for ADC development, because it is overexpressed in multiple solid tumors but minimally expressed in normal tissue and anti-ADAM9 antibodies are efficiently internalized and degraded by tumor cell lines.
At AACR in April, we presented data on ADAM9 expression in solid tumors and evaluated the activity of IMGC936 in clinically relevant patient-derived xenograft or PDX models with ADAM9 expression similar to that observed in human solid tumors. IMGC936 demonstrated compelling activity against a broad panel of PDX models, including non-small cell lung, triple-negative breast, gastric and pancreatic cancers.
We are actively enrolling patients with solid tumors known to express ADAM9 in a Phase I dose escalation study and collecting tumor tissue for retrospective ADAM9 expression assessment by immunohistochemistry. We're excited about the potential of this program, and we look forward to presenting data at a major medical meeting likely in early 2022.
With that, I'll turn the call over to Susan to cover our financials. Susan?
Susan Altschuller
Thanks Anna. For the first quarter of 2021, we generated $15.7 million in revenue, nearly all of which came from noncash royalty revenues.
Operating expenses were $44.6 million, comprised of $34.4 million of research and development expenses compared with $27.4 million for the first quarter of 2020. This increase was due to greater year-over-year clinical development costs related to advancing our SORAYA, MIRASOL and IMGC936 studies and greater external manufacturing costs.
G&A expenses were $10.2 million compared to $8.9 million for the first quarter of 2020, primarily due to increased professional fees and personnel costs. We ended the first quarter with $283.1 million in cash.
Our financial guidance for 2021 remains unchanged. We expect revenues to be between $65 million and $75 million, operating expenses to be between $200 million and $210 million and cash and cash equivalents at year-end to be between $140 million and $150 million.
We expect our current cash to fund operations into the second half of 2022. We look forward to what is ahead of us.
And with that, I'll open the call to questions.
Operator
[Operator Instructions] Your first question comes from John Newman of Cannacord. Your line is now open.
John Newman
Thanks for all the updates and thanks for taking my question. So Mark, I just wondered now that the top line data for SORAYA looks like it will surface in the fourth quarter of '21, might that allow you to give us a little bit more detail regarding the durability of responses when you present the top line data?
Thanks.
Mark Enyedy
Yes. And I'll ask Anna to comment any further, but the answer is yes.
Anna Berkenblit
Yes, that's exactly right, John. Given the pace of enrollment over the entire course of the study, including the last few months, we anticipate that we'll have not only top line ORR data for the primary endpoint, but we will also have a reasonable estimate of duration of response.
John Newman
And then I had just one follow-up question sort of on a different topic. So there's been a lot of activity recently with the FDA regarding accelerated approval.
Our understanding is that the agency actually views studies - companies that have studies already running at the time of accelerated approval that would be confirmatory as a significant positive. I just wondered if you could comment on your thoughts there.
It seems like if you've already got your confirmatory study up and running, the agency is more comfortable. Just curious as to how you think about that.
Thanks.
Mark Enyedy
Yes. Maybe just at a high level, I mean, that's, in fact, the regulatory guidance.
So when you talk to the FDA about an accelerated approval study, the first thing they say to you is, great, but we want to make sure you've completed enrollment in your confirmatory study at the time of regulatory action. So that's formal guidance that they provide every applicant.
So what happens in practice is that not everybody achieves that objective. We expect to be right in that place.
And then you saw the ODAC on some of the accelerated approvals, which Anna had the opportunity to sit through. And I think we were very pleased with the overall disposition of the ODAC relative to some of these so-called hanging approvals, so.
Operator
Your next question comes from Mr. Michael Schmidt of Guggenheim.
Sir, your line is now open.
Michael Schmidt
Thanks for taking my questions. I had a question on both ongoing studies, SORAYA and MIRASOL.
And perhaps related to your comments about the increased use of PARP inhibitors in recent years, just wondering how you think mirvetuximab might perform in a more heavily pretreated patient population with PARP inhibitors specifically?
Anna Berkenblit
Sure, Michael. So, PARPs are being incorporated into frontline maintenance for recurrent platinum sensitive maintenance therapy.
And we've absolutely seen, with each trial that we have enrolled over the past six years, an increasing percentage of patients receiving a prior PARP. And what I can tell you is we've looked across each study, and mirvetuximab really has nice activity regardless if prior PARP used it or not.
And that makes sense given that biologically, there is no reason to expect any kind of cross-resistance between our tubulin-directed payload and a PARP inhibitor which impairs the ability to repair DNA damage.
Michael Schmidt
Makes sense. And then a question on your new single-arm study in recurrent platinum sensitive patients.
Just wondering if you could help us maybe outline just sort of the size of the study potential timelines and also the size of the commercial opportunity perhaps relative to the SORAYA patient population.
Anna Berkenblit
Yes. So, we've designed this study of single agent mirvetuximab in patients with recurrent later-line platinum sensitive disease to really address an increasing platinum-sensitive disease to really address an increasing unmet need with a larger population of patients who technically are still platinum-sensitive by that rather arbitrary definition of recurring greater than six months after the last dose the platinum, but we know they're at high risk for allergic reactions or they're their bone marrow may be a little bit tired and they need other well-tolerated active therapies.
So from our Phase I study way back, we had a handful of patients - well, more than that actually - we had patients enrolled in a couple of our cohorts, the biopsy cohort and then the cohort with three to four prior lines of therapy who indeed had platinum-sensitive disease. And we - when we look at those patients, the activity of mirvetuximab looks quite nice.
And so, that has supported the study that we have just - we've just submitted the protocol to FDA. If you can think of it basically as a two-stage design study.
And so once we are ready to open the study, we'll share more details.
Mark Enyedy
Michael, just in terms of the market opportunity, our DRG data tell us that third-line platinum-sensitive patients are about 2,000 patients. Obviously, we're targeting only a subset of those folks but it's an evolving segment of the marketplace.
So, we won't get all 2,000 of those patients and it will depend, to a large degree, on the efficacy that we generate relative to what you see with platinum-based combinations in that setting and the data there are actually a little bit scarce. But based on what we've seen preliminarily, we think monotherapy can compete quite effectively there both in terms of efficacy but equally important tolerability and, to some degree, convenience as well.
Michael Schmidt
And then I know you did speak about a few new investigator-sponsored studies. I was just wondering if you could perhaps speak to evolving thinking about potentially supporting company-sponsored studies in earlier-stage patients.
Mark Enyedy
Sure. So, as Anna mentioned, we're really excited about this neoadjuvant study being conducted by Dr.
Arend led out of UAB for the reasons that she described. One, being in the frontline setting, having access to such - essentially fresh tumor tissue and being able to assess folate receptor alpha levels in those patients.
So, I think we're excited about that. And then, this study we're doing with Philip Harder and the AGO is a randomized controlled study of upwards of 140 patients.
So, we expect to have a pretty strong signal there in terms of direct comparison against the standard of care. And so, we are evaluating company-sponsored effort in that setting and working through the details of the design as we speak.
Operator
Your next question comes from Boris Peaker of Cowen. Sir, your line is open.
Boris Peaker
I just wanted to probe maybe initially in terms of the delay in the SORAYA study how is COVID impacting ovarian cancer. I'm just trying to understand since you aren't relying on new patients’ diagnosis, so shouldn't all the patients for the SORAYA trial already be kind of diagnosed in the system?
Mark Enyedy
Yes. I’ll let Anna give you a little more color.
But to start with, we're working with IQVIA as our CRO. And what they tell us is that in more than 70% of their studies, which include other ovarian cancer studies they saw a decline in accrual rates in the first quarter of this year in comparison to Q4 of last year.
So, there was a COVID impact. Part of what we’ve seen as well is there's some variability.
So, we’re normally - we're accustomed to seeing sort of a direct correlation between the number of sites that we have active in our accruals throughout the study and what we've seen in particular was acute during the early spring with some variability in accrual which we and CRO it should be to COVID.
Boris Peaker
It’s interesting. I guess my second question is on BPDCN.
Remind us again what do you need to show in that study for it to be considered successful?
Anna Berkenblit
Yes. So, the BPDCN frontline cohort to support full approval is enrolling.
And we've aligned with the FDA that it will include up to 20 frontline patients. These are patients who may have had local therapy surgery or radiation that have not had any systemic therapy.
And so the study is designed to rule out a CR/CRC or clinical CR rate of 10%.
Operator
Your next question comes from Andy Hsieh of William Blair. Your line is now open.
Mark Enyedy
Andy, are you there? Operator, I think we’ll probably go to the next question.
Operator
Hello. Andy?
Mark Enyedy
Well, we take the next question.
Operator
All right. Next question comes from Jessica Fye of JPMorgan.
Mark Enyedy
Jess? Operator, can you check the communications here?
Because it seems like we're missing two people already.
Operator
Yes. Just give me a second here, sir.
Hello, Ms. Jessica.
Your line is now open.
Luke Brennan
Hello. Can you guys hear me?
Mark Enyedy
Sounds like that’s Andy.
Luke Brennan
Sorry. Sorry.
This is this is Luke Brennan on for Jess.
Mark Enyedy
Oh, great. Okay.
Hi, Luke. Good.
Luke Brennan
Okay. Thank for the question this morning.
So, with the FDA feedback that you guys expect on the protocol, is the goal for the FDA to sign off on that single-arm trial in later-line platinum sensitive patients as the basis for approval?
Anna Berkenblit
No. So, basically, when we are getting ready to start a study, we submit the protocol to FDA.
There's a 30-day waiting period. And so, there's a good chance actually that we may not hear anything back from FDA.
We, of course are waiting, so that if they do have feedback, we'll have the opportunity to incorporate it before we enroll the first patient in this study.
Luke Brennan
I guess - so, I guess could you guys give a little bit more color on the dynamic between starting both the combo therapy and the monotherapy trials in the same setting?
Anna Berkenblit
So the monotherapy study is in patients with two or more prior lines for platinum. So, with at least two.
So, two to three prior lines of platinum therapy. And that really is a population that again is still technically platinum-sensitive but needs something else.
We are also planning to allow patients who had one prior line of platinum-based therapy but who had a hypersensitivity reaction that would make them inappropriate for further platinum. So that is a setting, again, we think we'll be increasing in frequency just because there are more patients with later line platinum-sensitive disease.
Our carboplatin combinations, one is the neoadjuvant setting, so that's upfront. And so those are patients who have not had any therapy before.
We're very excited about that, because that will be our first opportunity to study mirvetuximab in untreated patients. And then the randomized Phase II study, the IST that Mark mentioned being done in Germany, that's going to be a randomized study of mirvetuximab plus carboplatin versus standard, basically platinum-based doublets with standard-of-care maintenance therapy as appropriate for each patient.
Operator
Your next question comes from Andy Hsieh of William Blair. Sir, your line is now open.
Andy Hsieh
Thanks for taking my question. Sorry about the technical difficulty, and congratulations on the SORAYA enrollment completion.
I have two questions regarding kind of the label expansion opportunities. It might be a little bit early to answer this question, but the new kind of platinum-agnostic study that you're proposing, do you foresee MIRASOL potentially serving as a confirmatory trial for that opportunity?
And also, Mark, I'm just wondering if you can educate us on the compendia listing process. I'm just curious of how much interaction that you might have back and forth kind of relative to the regular FDA review process.
Anna Berkenblit
Yes. So I'll start.
So the new study that we are getting ready to start later this year of mirv monotherapy in recurrent platinum-sensitive disease, it's not exactly platinum-agnostic, Andy. These are patients who technically are still platinum-sensitive, having recurred greater than six months than the last dose of platinum.
Again, these patients need other non-platinum based options. So that study is slated to get going later this year.
I think it's unlikely that MIRASOL would serve as a confirmatory study for that. MIRASOL will likely read out prior to us completing the study that we're planning to start later this year Moving to compendia listing.
Typically, you need two separate studies to support compendia listing. And I think the best example for us right now is our combination data with mirvetuximab plus bevacizumab.
You may recall, we have one cohort specifically in platinum-resistant disease that was presented at ASCO a couple of years ago now, twice. And then we have our second cohort in platinum agnostic, so a broader population of patients with recurrent ovarian cancer.
That is another cohort, 60 patients. And again, we anticipate that the safety and efficacy data from those two separate cohorts will support compendia listing.
It may very well be the case that with mirvetuximab plus carboplatin based on the data we're planning to generate for that doublet, we could also gain compendia listing in advance of a formal label expansion from a registration trial.
Andy Hsieh
And then last question, Anna, I'm just curious about your thoughts on investigators learning curve and using MERV in the context of a clinical trial. So specifically, I'm just wondering if you expect to see some sort of safety or efficacy benefit from clinical sites that had participated in FORWARD I and are concurrently recruiting patients for SORAYA and MIRASOL?
Anna Berkenblit
Yes. So we have a wealth of data from the FORWARD I study, Andy, and it gives me a lot of comfort.
Because you may recall with FORWARD I, we went from 10 or 15 Phase I sites to over 100 sites for the Phase III study. And the safety profile of mirvetuximab in FORWARD I in 243 patients who were dosed with mirvetuximab looked quite good.
For me, the bellwether there is that only one of those 243 patients discontinued due to blurred vision, and that tells you that new sites, new investigators were very well informed and educated. We really did focus on that in FORWARD I, like we are in SORAYA and MIRASOL to manage patients appropriately on mirvetuximab, and I would expect no different in the SORAYA and MIRASOL studies.
I will say, you're absolutely right. We picked the best sites from FORWARD I to be included in SORAYA, and I think that was a really important strategy for us, both in terms of getting accrual completed and ensuring that we have optimal data integrity.
Operator
Your next question comes from Swayampakula Ramakanth from H.C. Wainwright.
Your line is now open.
Swayampakula Ramakanth
This is RK from H.C. Wainwright.
A couple of quick questions. Mark, as you embark the regulatory strategy with the two studies, SORAYA for accelerated approval and MIRASOL for full approval, you're also trying to evergreen mirvetuximab with various combination regimens being tested in the FORWARD program.
And so, what gives you the confidence and comfort to put a lot of resources behind this molecule when some could think it's a big bold step with no approval yet in any indication?
Mark Enyedy
So the first thing is we are looking at a relatively accelerated approval time line for mirvetuximab with the BLA submission in the first quarter of 2022. We have fast track designation for this product, and I think we could reasonably expect priority review, which gives us a relatively short window for review and approval.
Our objective then is to ensure that mirvetuximab can be used as widely as the data warrant. And so, this is why we placed some emphasis on the compendia listings that could be available to us at the time of initial approval.
And so the goal here is really to accelerate the penetration of mirv both within its label and then as physicians decide in their own discretion to use the product consistent with compendia listing that's available to them so that reimbursement would not be a barrier to that. So I don't - we don't view that as a high-risk strategy, particularly in light of the data that we've already generated.
So there's no further work really needed other than generating the actual publications from mirv in combination with avastin. And then when we look at the data that we've generated to-date, and particularly in some of these earlier line patients from some of our Phase I work, the data looked quite compelling in terms of the response rates that we've generated relative to current benchmarks.
And so you may remember from - it's a small end, but our initial carbo data in patients with high levels of expression was an 80% response rate and progression-free survival is 15 months. If you look at our common - our triplets that were published at ESMO, similarly, very high response rates.
And so our goals here are really to lever that. So I mean we have a lot of conviction that this drug should be the combination agent of choice for both avastin and carbo And I think it's our responsibility to accelerate that work, and part of that's just driven by our overall conviction about an initial approval and the availability of this drug in 2022.
Swayampakula Ramakanth
Perfect. Thank you.
On IMGN632, while certainly this drug also could target multiple liquid tumors, your initial focus is on BPDCN followed by AML. So do you - or should we expect following what you're trying to do with broadening the profile of 632 in additional liquid tumors?
What would be your plans on that?
Mark Enyedy
Right. So I mean high level with our portfolio, our ethos in terms of pursuing development is fast-to-market strategies where we can use single-arm studies to support accelerated approval in the case of mirvetuximab.
In the case of 632 and BPDCN, we'll have full approval. But you may recall that we got breakthrough therapy designation for that program in relapsed/refractory and align with FDA around an additional cohort in frontline patients, which we are pursuing as we speak.
But yes, our goal is to - CD123 is expressed across a range of hematologic malignancies. And our principal foray there has been in acute myeloid leukemia.
Initially, as monotherapy, where we saw some interesting activity, but clearly, the benchmark has been set in that disease with the combination of azacitidine and venetoclax. And so, the goal was to integrate 632 into that doublet to create - looking at both doublet and most importantly, I think, a triplet to see whether we can generate response rates and duration of response that would make that regimen competitive.
We're working through that as we speak, and we expect to have data at ASH at the end of the year with the triplet. But yes, that represents a significant potential expansion beyond the BPDCN label.
Operator
Your next question comes from Kennen MacKay of RBC Capital Markets. Your line is now open.
KennenMacKay
Thanks for taking the question. [technical difficulty]
Mark Enyedy
Kennen, you're breaking up substantially. I couldn't - I only make out about every third word.
Kennen MacKay
[technical difficulty]
Mark Enyedy
I did not get that, Kennen, apologies. So maybe we can follow-up off-line.
Sorry, yes. Operator, go to the next question.
Operator
Next question comes from Joe Catanzaro of Piper Sandler. Your line is now open.
Joe Catanzaro
Thanks so much for taking my question. Maybe just one quick one for me to follow-up on the single-arm monotherapy trial in platinum-sensitive patients.
So Anna, you had mentioned that way back in the Phase I experience, you actually had enrolled platinum-sensitive patients. I'm wondering if maybe you could elaborate a little bit more on what exactly you saw in those patients.
And specifically, how it relates to folate receptor expression levels and the various cutoffs that you utilized back in that Phase I trial? Thanks.
Anna Berkenblit
Yes. Sure, Joe.
So as I mentioned, we had the biopsy cohort, which was silent on platinum status. And we also had what we've affectionately called the eye drop cohort in patients with three to four prior lines of therapy regardless of platinum status.
That was back in the day when olaparib got its accelerated approval initially as treatment in patients with three to four prior. So we were sort of following that model.
As a result, even though our intent at the time was really not to focus on platinum-sensitive disease, we did enroll enough patients that across those two cohorts with later-line disease. I mean, these were patients with three prior lines of therapy and had a very nice - the FR alpha high patients had a very nice response.
So these are our internal data that we're using to support the design of the single-arm study that is on-track to get open later this year. And we're very pleased with the data that we have from that Phase I experience.
And so again, we're going to have - it's basically a two-stage design. And once the study is up and running, we can sort of talk more about the actual design specifics and timelines.
Operator
Next question comes from Kelly Shi of Jefferies. Your line is now open.
Kelly Shi
I have one question from one of your early phase trials. So the 936, the ADAM-targeting ADC, you recently showed a nice proof-of-concept data at AACR.
I'm wondering, do you think ADAM9 is predictive for the treatment efficacy based on biology? And also, are you going to screen patients after dose escalation phase?
Is there any companion diagnostic development ongoing at ImmunoGen? And also, lastly, what has been learning from previous ADAM-targeting antibodies, if there are any?
Thank you.
Anna Berkenblit
Sure. So ADAM9 is a member of the matrix metalloproteinase and disintegrant family.
And I certainly remember the days that we were targeting MMPs, matrix metalloproteinase, to try to prevent metastasis and invasion. And those mechanistically oriented approaches really didn't turn out so well for cancer patients.
However, ADAM9 is really - we're using it as a ZIP code to target our very potent next-generation maytansinoid toxic payload to tumor cells and to spare normal tissue. So it's really not - I wouldn't think of it as a biological mechanistic rationale, but really more targeting our toxic payload to the tumor cells.
In terms of your next question around screening, we are generating data now in Phase I dose escalation to inform whether or not we will need to select patients for ADAM9 expression or not. As you saw in our AACR poster, ADAM9 is actually reasonably highly expressed across a broad range of tumors.
But we will be poised to select patients by ADAM9 expression and develop a CDX with a cutoff, a validated cutoff if needed. And right now, we're doing all of the spadework to get us to that point if needed.
And then your last question around learnings from prior ADAM9 targeted antibodies, I really can't speak to that because this is a novel target. MacroGenics brought the target and their antibody to us and collaboratively, we've developed this ADC.
So we're really excited. The Phase I dose escalation trial is enrolling, and we look forward to sharing data in early 2022.
Kelly Shi
Thank you very much. It's very information.
I also have another quick question regarding the upcoming ASCO update for the mirv lasting combo in the platinum-agnostic patients. I just wonder what is the estimated ORR and PFS achieved by standard-of-care in this full late receptor alpha high population?
Or in another way, I should ask, what should be the benchmark for this selective patient population? Thank you.
Anna Berkenblit
Yes. So there's two separate populations, if you will: platinum-resistant and recurrent platinum-sensitive.
In unselected patients, platinum-resistant disease I would point you to the AURELIA study that looked at avastin plus chemotherapy, which had a 27% or 28% confirmed response rate and a median PFS of 6.7 months. They did not assess for folate receptor alpha in AURELIA, so I don't know how the upper alpha high patients did.
But what I can tell you is there are studies that have been published, mostly retrospective, looking at FR alpha is potentially a poor prognostic factor. And if you look at our exploratory analyses from FORWARD I at ESMO in 2019, you'll see there may be something to that but certainly not anything that I would use to design a study assuming high FR alpha patients would do worse than the overall population with standard-of-care.
Moving to recurrent platinum-sensitive disease, I would point you to the GOG 213 study and the OCEAN study, looking at patients with one prior line of therapy, and there the response rate is in the mid-50s and the PFS for platinum-based doublets is somewhere between 8.5 and 10.5 months. So keep that in the back of your mind when you see our data from our mature mirv cohort that Dr.
O'Malley will be presenting at an oral presentation at ASCO.
Operator
Now I would like to hand the call over back to our presenters for their final comments. Presenters, please go ahead.
Mark Enyedy
Thank you. Well, we appreciate your time this morning.
We look forward to keeping you apprised of our product and progress in the year. And in particular, seeing you or at least on Zoom anyway for ASCO and the data updates there.
Thanks.
Operator
This concludes today's conference call. Thank you all for joining.
You may now disconnect.