ImmunoGen, Inc. (IMGN) CEO Mark Enyedy on Q4 2019 Results - Earnings Call Transcriptby SA Transcripts, https://seekingalpha.com/author/sa-transcripts
ImmunoGen, Inc. (NASDAQ:IMGN) Q4 2019 Results Earnings Conference Call February 14, 2020 8:00 AM ET
Courtney O’Konek - Senior Director of Corporate Communications & IR
Mark Enyedy - President, CEO, Interim Principal Financial Officer
Anna Berkenblit - Senior VP & Chief Medical Officer
Theresa Wingrove - SVP of Regulatory Affairs & Quality
Dave Foster - Chief Accounting Officer
Conference Call Participants
John Newman - Canaccord
Biren Amin - Jefferies
Andy Hsieh - William Blair
Boris Peaker - Cowen
Jessica Fye - JPMorgan
David Ruch - SVB Leerink
Kennen MacKay - RBC Capital Markets
Good morning, and welcome to ImmunoGen’s Fourth Quarter and Full Year 2019 Financial and Operating Results Conference Call. Today's conference is being recorded.
At this time, I would like to turn the call over to Courtney O’Konek, Senior Director of Corporate Communications and Investor Relations. Please go ahead.
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 and fourth quarter and full year 2019 financial results. This press release and web stream 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; and Anna Berkenblit, our Chief Medical Officer. Theresa Wingrove, our Senior Vice President of Regulatory Affairs and Quality; and Dave Foster, our Chief Accounting Officer, will also join us for Q&A.
During today's call, we will review key accomplishments for the business over the last 12 months, our financial results and upcoming milestones. 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.
Thanks, Courtney. Good morning, everyone, and thank you for joining us today. In our comments this morning, Anna and I will recap our progress over the last 12 months and then highlight the milestones we anticipate for a productive year ahead.
2019 was a challenging year for us. As we reported in March, the Phase III study for our lead program, mirvetuximab, did not meet the primary endpoint. Since then, we have restructured the business to reduce our cost, prioritized our portfolio to focus on our most promising programs and worked closely with FDA to define an accelerated path to approval for mirvetuximab in ovarian cancer. With the benefit of these steps, we've emerged with strong prospects for ImmunoGen as we move into 2020.
In particular, looking at the business today, the data we’ve generated from the Phase III study of mirvetuximab give us a clear view of which patients benefit most from mirvetuximab and how best to identify those patients. This, in turn, gives us confidence that our next studies with mirvetuximab will produce positive outcomes.
To this end, we have aligned with FDA that a single-arm study in women with folate receptor alpha high platinum-resistant ovarian cancer who have been previously treated with Avastin could support accelerated approval. We called this study SORAYA and expect to enroll the first patient this quarter, with top line data anticipated in mid-2021, followed by a BLA submission in the second half of 2021 and a potential approval in 2022. Beyond the first approval, we have ongoing studies to expand the potential indications for mirvetuximab with additional data this year.
Our portfolio also includes three additional programs targeting a range of tumor types in both hematological malignancies and solid tumors, each with important milestones this year, which I'll cover in a moment.
From a financial perspective, we ended 2019 with just over $175 million in cash on the balance sheet. We recently completed an upsized follow-on offering that generated roughly $98 million in net proceeds. We will provide detailed guidance later in the call. So suffice it to say that this cash position will allow us to advance our portfolio through material inflection points, including the initial approval of mirvetuximab.
With this combination of assets and an experienced management team, we are well positioned to execute on our strategy and generate significant value, both short and long term.
As a reminder, we have set three strategic priorities for the business. First, obtain an initial approval for mirvetuximab as monotherapy in platinum-resistant ovarian cancer and then look to expand into earlier lines of therapy.
Next, accelerate our early-stage portfolio with an emphasis on our program in hematological malignancies. And finally, expand our reach, gain access to complementary capabilities and strengthen our financials through partnering.
We have made significant progress with each of these priorities and expect continued momentum as we head into 2020, with a number of important milestones this year. These include for mirvetuximab, opening the SORAYA Trial in the first quarter, continuing to enroll patients in our confirmatory Phase III MIRASOL Trial and presenting data from our platinum-agnostic and platinum-sensitive combination studies.
For our program in hematological malignancies, we continue to advance IMGN632 in the clinic and expect to present monotherapy data in BPDCN and MRD+ AML, along with combination data in AML at ASH later this year.
For our preclinical programs, we expect to file an IND for IMGC936, our novel ADAM9-targeting ADC, during the first half of the year; and to advance IMGN151, our next-generation FRα targeting ADC, into preclinical development. So an exciting year ahead.
Turning to our financials. The details are covered in the press release issued this morning, so just a few summary results. For the full year 2019, we generated $82.3 million in revenue, comprised of $47.4 million of non-cash royalty revenues and $34.8 million from license and milestone fees, of which $15.2 million in related cash will be received in 2020.
Operating expenses were $174.4 million, comprised of $114.5 million in R&D expenses compared to $174.5 million in 2018. This $60 million decrease was driven by lower expenses resulting from the restructuring of the business at the end of the second quarter of 2019 and the closing of our manufacturing facility at the end of 2018, lower external manufacturing cost due to the activity to support commercial validation of mirvetuximab in the prior year and decreased clinical trial expenses driven by lower activity in the FORWARD I Phase III clinical trial.
G&A expenses were $38.5 million compared to $36.7 million in 2018 primarily due to higher allocation of facility-related expenses for excess laboratory and office space resulting from the restructuring. In addition, we incurred a $21.4 million restructuring charge in 2019.
We ended the year with $176.2 million in cash on the balance sheet. As I mentioned earlier, we strengthened our cash position with an upsized follow-on offering, which added approximately $98 million in net proceeds to our balance sheet.
In terms of financial guidance for 2020, we expect revenues to be between $60 million and $65 million, our operating expenses to be between $165 million and $170 million and our cash at year-end to be between $170 million and $175 million.
We expect that our current cash, inclusive of the proceeds of the follow-on offering and anticipated cash receipts from partners, will fund our operations into the second half of 2022.
With that, I'll turn the call over to Anna to review our pipeline progress in more detail. Anna?
Thanks, Mark. First, I'll review SORAYA and MIRASOL, and we'll then provide details on our presentations at ASH.
SORAYA and MIRASOL. As part of a productive dialogue last year, FDA advised us the new single-arm trial in patients with platinum-resistant ovarian cancer could support accelerated approval for mirvetuximab, provided that overall response rate and duration of response surpassed those of the best available therapy at the time of regulatory action.
As part of this guidance, FDA advised that the relevant benchmark for currently available therapy is a 12% overall response rate. Based on this feedback, we will begin enrolling patients in SORAYA this quarter.
SORAYA is a pivotal single-arm trial evaluating mirvetuximab monotherapy in approximately 110 women with platinum-resistant ovarian, primary peritoneal or fallopian tube cancer that is FRα high as measured by PS2+ scoring, who have been previously treated with bevacizumab.
We have reviewed the data generated from our previous trials with mirvetuximab, including a pooled post hoc analysis of our Phase III FORWARD I trial using a PS2+ rescoring method to assess tumor samples for FRα expression, along with patients from Phase I and have identified 70 patients whom we believe would have met the key eligibility criteria for SORAYA. Each has platinum-resistant ovarian cancer with FRα high expression and received 1 to 3 prior lines of therapy, including prior bevacizumab.
Based on an analysis of these 70 patients, the overall response rate was 31.4% with a median duration of response of 7.8 months. We believe that these data compare favorably to the response rates seen with single-agent chemotherapy in platinum-resistant ovarian cancer, which was 11.8% in the AURELIA trial and 12.2% in the CORAIL trial, both of which included patients naive to and previously treated with bevacizumab.
As Mark mentioned, we expect to report top line data from SORAYA in mid-2021. And if positive, submit an application for accelerated approval of mirvetuximab based on these data during the second half of 2021.
Moving to MIRASOL. You may recall, following the results of our Phase III FORWARD I study, we conducted exploratory analyses to assess the factors that may have contributed to a negative statistical outcome in FORWARD I.
We identified what we believe to be the key factors, and designed MIRASOL accordingly to improve the probability of technical success, including reverting to the original PS2+ scoring method to select those patients most likely to benefit from mirvetuximab.
MIRASOL will enroll approximately 430 patients with folate receptor alpha high platinum-resistant ovarian cancer, who have been treated with up to three prior regimens. Patients will be randomized 1 to 1 to receive mirvetuximab or an investigator's choice of chemotherapy, paclitaxel, pegylated liposomal doxorubicin or topotecan. The primary endpoint is PFS by investigator and the secondary endpoints are overall response rate, overall survival and patient-reported outcomes.
If we receive accelerated approval for mirvetuximab based on the results of SORAYA, we expect that MIRASOL would serve as a confirmatory trial to support full approval of mirvetuximab. We look forward to continuing enrollment in MIRASOL this year and expect to report top line data in the first half of 2022.
In parallel, we continue to advance our combination cohorts with mirvetuximab as we look to move this drug into earlier lines of therapy. We anticipate presenting updated data from our Phase Ib FORWARD II platinum-agnostic doublet cohort, evaluating mirvetuximab in combination with Avastin at ASCO this year; and updated data from our platinum-sensitive triplet cohort evaluating mirvetuximab in combination with carboplatin and Avastin in the fall.
Lastly, we plan to initiate in mid-2020, an additional study in platinum-sensitive disease, evaluating mirvetuximab in combination with carboplatin. This will be an investigator-sponsored trial in over 100 patients, randomizing them to either the mirvetuximab-carboplatin combination or an investigator's choice carboplatin-based regimen.
I'll now briefly review our progress with our early-stage portfolio. At ASH, we presented updated safety and efficacy findings from the dose escalation and expansion of our Phase I study of IMGN632 in patients with relapsed or refractory AML and BPDCN.
IMGN632 is a CD123 targeted ADC that deploys our most potent IGN payload. And the updated findings demonstrated anti-leukemia activity across all those dose levels tested, along with a well-tolerated safety profile and activity at doses up to and including 0.09 milligrams per kilogram per cycle.
We have selected a recommended dosing schedule for Phase II. And believe that the antitumor activity, favorable tolerability and the convenience of a short infusion reinforce the ongoing expansion of IMGN632 monotherapy in BPDCN, AML and ALL.
Additionally, we initiated our IMGN632 combination trials with azacitidine and venetoclax in relapsed and frontline AML as well as IMGN632 as a monotherapy in minimal residual disease-positive AML patients. And look forward to continue engaging enrollment in 2020 and sharing data at ASH.
With that, I'll turn the call back over to Mark for some closing remarks.
Thanks, Anna. Just a few thoughts before we open the call for Q&A. After a challenging year, we've emerged with strong prospects for the business with important near-term catalysts for our lead program, our earlier-stage portfolio accelerating, a strong cash position to advance our portfolio to material inflection points and an experienced management team to deliver on the business. We look forward to an exciting and productive next 12 months.
And with that, we'll open the call for questions.
Thank you. [Operator Instructions] Our first question comes from John Newman of Canaccord. Your line is now open.
Hey. Good morning, guys. Thanks for taking the question. So a question for Anna and Mark. Just curious if you could give us a rough sense as to the number of patients for the FORWARD II platinum-agnostic doublet that we might see midyear? And wondering if any of the patients within that group would have received prior Avastin therapy? Thanks.
So the - yes, sorry. So the cohort is 60 patients, and yes, a number of those patients will have received prior Avastin. I can't say right at the top of my head how many that is.
Okay. Great. And then just a quick question on SORAYA. I'm assuming that, given in the U.S., getting reimbursement for more than one line of Avastin has been a little bit challenging until recently. I'm wondering if the patients in SORAYA will have just one prior line of therapy with Avastin or if you might have a few patients that would have more than one?
Thanks, John. So SORAYA is being enrolled in the U.S. as well as in Europe. And historically, typically, patients really only get one line of Avastin, if they do have access to it at all. And remember, this is patients with platinum-resistant disease with 1 to 3 priors.
So the only data that I'm aware of really showing that Avastin - after Avastin works is from the MITO/MANGO study, where it was shown that after frontline treatment with an Avastin containing regimen, you still got benefit the recurrent platinum-sensitive setting with another Avastin regimen. So we anticipate that very few patients will have had more than one prior line of Avastin.
Okay, great. Thank you very much.
Thank you. And our next question comes from Biren Amin of Jefferies. Your line is now open.
Hey. Hi, guys. Thanks for taking my questions. Anna, on the FORWARD II trial with the triplet, can you just maybe give us what the next steps are? I think in 2019, you presented some data there in about 41 patients, saw pretty strong response rates and DOR. How much additional data do you need to see before you move the triplet forward into a pivotal study?
Yeah. So we will be presenting longer-term data from the triplet likely at ESMO this year, where we should have mature PFS data. You may recall that the benchmark for other triplets, so carbo-gem-bev and carbo-pac-bev, there, the median PFS is somewhere around 12 to 14 months. Carbo-doxil-bev also read out at ESMO last year or the year before, also looking similarly.
So those are the benchmarks. And so we'll see how our triplet stacks up in terms of PFS as well as safety and tolerability and then we'll take it from there. Any potential registration option for that triplet would be a large, long trial. So we'll be examining the data quite closely.
Okay. And then on IMGC936 of the ADAM9 ADC, you had presented, I think, last year, at AACR, some preclinical data? And given you're moving this program into IND, are you going to be stratifying based on ADAM line expression? And I guess, what tumor types are you looking at in the Phase I tail?
Yeah. So we will be assessing ADAM9 levels, and we will be poised to have a companion diagnostic down the road if needed for patient selection. So early on, we'll be gathering data.
The 4 tumor types we're initially going to target include pancreatic, gastric, lung and triple-negative breast cancer. There are some other solid tumors that also express ADAM9, but these are the 4 that we're going after first in the Phase I study. And based on what we see in dose escalation, we can then certainly do some expansion cohorts.
Great. Thank you.
Thank you. And our next question comes from Andy Hsieh from William Blair. Your line is now open.
Great. Thanks for taking my question. So, one for Mark. I think the company has been restructuring for the past 2 or 3 quarters. Just wondering if the accelerated approval pathway that was clarified in December changed the course of that?
Yeah. So thanks for the question, Andy. The - we took the largest part of the restructuring took place in Q2 and early Q3. And we were targeting a headcount number, and there were folks that were transitioning over the back half of the year. And we sort of got to, what I'll call, a nadir in terms of headcount.
And with the benefit of the FDA guidance around SORAYA, we've actually begun to add a very modest number of heads as we go forward. And so you'll see from the guidance that we gave, our operating expenses for in 2020 are going to be in the same range as they were for 2019 on an aggregate basis.
And so what that reflects are sort of a leveling of the headcount with, as I said, some modest additions, particularly in the clinical and regulatory group from where we thought we were going to be. And then a significant ramp in external expenses versus, say, where we were in Q3 of 2019, reflecting the concurrent execution around both SORAYA and MIRASOL. And then ultimately, bringing online 936 later in the year.
Okay. Excellent. So in terms of - from a, I guess, FDA dialogue perspective, I was very intrigued by the randomized investigator-sponsored doublet. Just curious about kind of potentially adding that high-quality data in the regulatory packages. I just wanted to know if there's any sort of mechanism by which you can include investigator-sponsored trial in a regulatory package?
Hi. This is Theresa. Yes, there are certain opportunities to include ISTs. The data has to be robustly collected, but FDA would consider that data. This is a combination trial, though, however, so it could not be used to support the evaluation of efficacy for monotherapy.
Okay. Got it. And lastly, I think for Anna. So I guess, immunotherapy hasn't really been used in that, but Roche is running a Phase III trial that may readout this year. So just curious if in Phase Ib monotherapy, combination or FORWARD I, do you guys look at any IO treated population and how they did with mirv?
So you're right, Andy, that checkpoint inhibitors have not really moved the needle in ovarian cancer. And I think the large Phase III that you're referring to is the IMAGINE study. In terms of us - yes, and that's in the frontline setting, incorporating atezolizumab.
In terms of us, looking at our data set, looking at patients who've had prior checkpoint inhibitors, honestly, there hasn't been enough of them given sort of when we enrolled FORWARD I. So I can't really speak to it.
But I will say, given the modest activity, like single-digit response rates for checkpoint inhibitors by themselves, and given the lack of any potential cross resistance, I don't think prior checkpoint inhibitor therapy would impact mirv activity.
Got it. Great, that’s really helpful. Thank you very much.
Thank you. And our next question comes from Boris Peaker of Cowen. Your line is now open.
Great. A couple of questions. So first, on the combo trials, I'm just curious, what's the regulatory strategy in general? Is the goal to select the best combo and move that forward? Or do you anticipate to advance several different combinations somehow in parallel?
Yeah. So the first step with the combinations is to ensure, at the time we have regulatory action on the monotherapy around a positive outcome from SORAYA, that we would have sufficient publications to support a compendia listing for the combinations. And so that's our initial goal. So that - to the extent there is discretionary use by physicians, that they can obtain reimbursement for that use.
Yes, longer term, the - our goal is to have an expanded label, particularly to embrace platinum-sensitive patients. And so evaluating these combinations and also in the segment of what we're calling platinum-agnostic patients, trying to define a path forward there.
So the opportunities here are, one, looking at doublet with carbo and comparing that to investigator's choice. And that's what Hoarder [ph] is doing for us with the AGO in Germany with this large IST. I think that would be a good guide for us. The data that we will have at ASCO in June with this platinum-agnostic cohort equally provides us with a strong signal in terms of where we might go with the program.
And as Anna mentioned earlier, on the - as we think about the triplet, some of those studies get to be very, very large. And I think we would likely look to cooperative groups to help with any of those broader studies.
So what I would say is stay tuned. We've gathered a lot of data. The key points to date are, first, that we can combine full doses of mirvetuximab with full doses of everything we've tried at this point without generating new safety signals. So the drug is well tolerated in combination.
The efficacy benchmarks that we've hit with mirvetuximab have exceeded the comparable. So if you look at our Avastin combination data relative to what was reported, and really, we compare very favorably there. The triplet compared favorably to - and these are high benchmarks, too. I mean some of the studies with triplets are in the low 80s. And when we look at apples-to-apples, we've got to a 90% response rate in those patients.
So we're encouraged. And I think the question will be, what can we do on our own, what could we rely on the cooperative groups? And along the way, ensuring that to the extent that physicians are encouraged by the early data and want to use the drug, that they can obtain reimbursement here in the U.S.
Got you. My second question is on 632. Just curious what indications do you see as having the shortest path to approval?
Yes. BPDCN, so we reported data on a small cohort of 9 patients at ASH, and we had 3 responders in that group, all of which or all of whom had previously received ELZONRIS. And so the goal for us is to collect sufficient data in this relapsed BPDCN population to see whether we can create a dossier sufficient to approach FDA for a breakthrough therapy designation in this patient population. And as part of that discussion, define how many additional patients they would like to see in order to support an accelerated approval for that indication.
And so you may remember that I think the number of patients supporting the Alzheimer's approval was around 50, between 50 and 60. And so those numbers could be reasonably modest. And what we've done with 632 is go to Europe and open sites, and the investigator and patient response there has been quite encouraging from an accrual standpoint.
You may remember that Stemline did not go to Europe with that drug. And so we've been able to take advantage of that from a patient accrual perspective, which I think will allow us to accumulate the data we need to go have the conversations with the FDA.
Got you. Maybe just the last question on IMGN151, how does that differ from rituximab?
Yes. So we have a new linker and payload for that program, and then we've also done some antibody engineering to improve the PK. And so we will have data at AACR in April, where we can talk in more detail about the improvements that are reflected or embodied in that molecule.
Great. Thank you very much for taking my questions.
Thank you. [Operator Instructions] And the next question comes from Jessica Fye of JPMorgan. Your line is now open.
Hey, guys. Good morning. Thanks for taking my questions. If you have SORAYA data in mid '21 and file that in the back half of '21, what are the potential implications to that review if MIRASOL fails to meet at some point while that BLA is under review with the FDA?
Well, so SORAYA is based on a surrogate endpoint. I think if - I think we would be challenged, candidly, if the - given the accelerated approval based on overall response and DOR as a surrogate. If we then came out with data in MIRASOL that showed no statistically significant difference on a full approval endpoint, I think that would be a challenging circumstance for the agency.
And just thinking about the time lines here, I think clinicaltrials.gov is pointing to June of 2022 for MIRASOL, so yeah, first half, but conceivably could readout after that decision.
Is it possible that, that the time lines kind of play out that way, where you get the accelerated approval in MIRASOL readsout after FDA has kind of made a call on the SORAYA time line?
Yeah. I think that's probably the more likely scenario here. And I get there in the following way, so we previously have drafted substantial segments of the BLA for mirvetuximab, and those things are not going to change as it relates to preclinical and so on.
So essentially, what we're looking for is a clinical component to the BLA. So our view is that we can move very quickly from the readout of the top line data to the submission for - supported by SORAYA. We've got priority review for this.
And we have contractors initiating [ph] to state approval...
Yeah, sorry. Thank you. And so my sense is that the FDA, particularly in these patient populations where there is significant unmet need and that was one point of very clear alignment between us and the agency around these platinum-resistant patients previously treated with Avastin.
So our expectation is they're going to move quite quickly on this application. And so we're saying 2022 because that is a reasonable time line for them to act on this application. But in cases where they have - where data are good and the need is high, they've acted in a shorter time frame, in 3 or 4 months in some cases. And so we'll see. But I do think that the likely scenario is regulatory action on SORAYA, followed by a readout of MIRASOL.
Okay. Got it. And when we think about the 70 patient kind of group who look like they would meet the enrollment criteria for SORAYA. I'm just trying to think about - are you going to present that analysis, so we can kind of take a look at it and see more nuance around the number of priors and background therapies those folks have had?
I'm wondering if those patients might - given kind of the mix of trials that came from, might end up being a little bit sicker on the margins than the ones who are going to end up being enrolled in SORAYA?
So we don't have any plans to formally present additional details on those 70 patients, Jess. We did a lot of spadework looking through our program to really understand who the patients are who've already been treated with mirvetuximab to give us confidence that SORAYA will have a high probability of technical success.
So at a very high level, these are all patients with platinum-resistant ovarian cancer. They've all had 1 to 3 prior lines of therapy. They're all FRα high by PS2+. And they've all had bevacizumab at some point prior to receiving mirvetuximab.
The vast majority of them came from the Phase III trial, and about - somewhere around 14 or 15 of them came from the Phase I trial. So we've looked throughout, and we're confident that we will be able to replicate these data in terms of ruling out a 12% response rate.
The one very minor nuance that may be informative for you is that when we enrolled - when we designed FORWARD I, we excluded primary platinum-refractory patients. And there, those were patients who progressed within 4 weeks of platinum - of their last dose of their first-line platinum. Subsequently talking with key opinion leaders, they have suggested that the primary platinum-refractory disease should really be those patients who progress within 3 months of the prior platinum.
So we are not enrolling those patients in FORWARD I, nor - sorry, we're not enrolling them in SORAYA and MIRASOL moving forward. In the randomized trial setting, that would have a similar impact probably on both arms, not so much on SORAYA, but the benchmarking we've done for SORAYA takes that into consideration as well.
Got it. Thank you.
Thank you. And our next question comes from Jonathan Chang of SVB Leerink. Your line is now open.
Hi, guys. This is David Ruch on for Jonathan. Thanks for taking our questions. You guys have mentioned in the past, the neoadjuvant opportunity for mirv plus chemo, and it seems like a setting where KOLs will be receptive to using an ADC. Could you just elaborate a little bit on how you're thinking about potential combinations and design of these studies down the road?
You're absolutely right. A neoadjuvant trial is a high priority for our investigator-sponsored trial strategy. And all I can say is we're having active discussions, and we're really excited to be in a position to have the discussions and get a trial up and going with our investigators.
All right. Great. And to clarify, that would be an IST or...
Okay. Okay, great. Thank you. And next for me, now that the FORWARD I data are a little bit more mature, have you considered presenting any type of retrospective biomarker analysis that maybe looks at the longitudinal expression of foliate receptor alpha in these patients over time?
So that would require serial biopsies, which were not mandated as part of the protocol, so patients who were enrolled primarily based on archival tumor tissue from their initial diagnosis. If, for whatever reason, archival tissue was not available, they could have had a fresh biopsy, but we were not subjecting these patients to sequential biopsies during their participation in the Phase III trial. So unfortunately, we would not have the data available that you're requesting.
Okay. Okay. Do you think that this might be something you do in SORAYA? Would you have pre and post-study biopsies or...
So we did have a biomarker expansion cohort in our Phase I that we presented at SGO several years ago now. And really, it was that study that showed that there was reasonable concordance between archival tissue and fresh tissue. And then we did biopsies after 2 cycles.
I should note that there were a bunch of patients who had such tumor shrinkage on that arm that they couldn't actually get a biopsy after 2 cycles, so we had to over enroll the cohort. That cohort also allowed for biopsies at progression, and you can imagine that that's a pretty hard conversation for an investigator to have with a patient saying, I'm sorry, the drug is no longer working, we'd like to subject you to a biopsy to see what's going on. At that point, patients typically prefer to engage in conversations around what's next from a treatment perspective.
All right. Thank you very much.
Thank you. And our next question comes from Kennen MacKay of RBC Capital Markets. Your line is now open.
Hi. Thanks for taking the question. Just wondering in BPDCN, if you could help us understand sort of where the efficacy bar is behind ELZONRIS? And if that is sort of the area of highest unmet medical need? Or as you're looking at potentially going through a breakthrough designation process here or a potential regulatory trial design, if you could go potentially in front of that or does it have be behind? Thank you.
Yeah. So as Mark mentioned, ELZONRIS was approved based on somewhere around 50 or 60 patients worth of data for BPDCN, a larger safety database. But the responses in the label for ELZONRIS in the relapsed setting are - I think it was 2 out of 13 patients. Certainly, if you look at their New England Journal article, they had additional partial responses, but those were not considered by FDA. And then if you look in the frontline setting, Alzheimers' response rate was certainly higher.
So we think there is a high unmet need for patients who've already had ELZONRIS. And I think the 3 out of 9 responders that we've had, certainly, from a proof-of-concept perspective, while small numbers, is quite encouraging.
We're also hearing that not every patient is appropriate for ELZONRIS. Certainly, if you look at the label with the potential for capillary leak, there patients with low albumin are not appropriate for ELZONRIS. And patients with cardiovascular or renal comorbidities who perhaps couldn't handle the cardiovascular challenge that capillary leak would pose for them.
That might be another area where we might be able to demonstrate both activity as well as safety that could be supportive of going upfront in frontline BPDCN patients who have not been previously treated with ELZONRIS.
And at this point, our heads are down. We're enrolling patients. We're gathering the data so that we have an informative data set with which to engage the regulators.
Interesting. Thank you. And then could we see an update from an expansion of that at EHA? Or would that be ASH later this year?
I would suspect that ASH would have a bigger data set with longer duration, which will be important.
Okay. Thank you very much.
Thank you. And ladies and gentlemen, this does conclude our question-and-answer session. I would now like to turn the call back over to Mark Enyedy for any closing remarks.
Great. Thanks, Sonia. Very much appreciate the participation and good questions today, and we look forward to keeping you updated on our progress throughout the remainder of the year. Thanks very much.
Ladies and gentlemen, this concludes today's conference call. Thank you for participating. You may now disconnect.