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Immunogen Inc (IMGN)
Q1Â 2020 Earnings Call
May 1, 2020, 8:00 a.m. ET
Contents:
- Prepared Remarks
- Questions and Answers
- Call Participants
Prepared Remarks:
Operator
Good morning and welcome to ImmunoGen's First Quarter 2020 Financial and Operating Results 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. Please go ahead.
Courtney O'Konek -- Senior Director of Corporate Communications and Investor Relations
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 first quarter 2020 financial results. This press release and a web stream of this call can be found under the Investor and 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. 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 three 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.
Mark Enyedy -- President and Chief Executive Officer
Thanks, Courtney. Good morning, everyone, and thank you for joining us today. During the first quarter, we moved forward with our registration studies for mirvetuximab and advanced our portfolio of earlier-stage programs, while adapting to meet the evolving challenges of COVID-19. Despite the potential hurdles of operating remotely, we opened SORAYA and expanded our activated sites for MIRASOL during the quarter, and expect to maintain the timelines for topline results for both studies. In parallel, we are pleased to have data from our Avastin expansion cohort in platinum-agnostic ovarian cancer selected for a virtual oral presentation at ASCO in late May, and as Anna will describe in more detail in a moment, our preclinical programs remain on track for key milestones this quarter. Finally, building on the momentum generated at the close of 2019, we strengthened our balance sheet with an upsized and oversubscribed follow-on offering in January, which raised approximately $98 million in net proceeds.
In terms of our ongoing response to the pandemic, with the benefit of early indications of COVID-19's impact here in Boston, we implemented business continuity plans in the first half of March. These plans have allowed us to operate our core functions effectively in a virtual working environment and rapidly adapt in response to new developments.
Focusing on our key development programs, I want to share with you our experience to date on three parameters; drug supply, regulatory interactions, and clinical trial execution. From a supply chain perspective, we entered the year with ample drug product and have more than enough inventory on hand to complete all of our ongoing mirvetuximab monotherapy and combination trials, IMGN632 expansion studies, and the upcoming Phase 1 trial for IMGC936. Furthermore, our partners at Almac have taken prospective measures to ensure that our currently activated sites have sufficient safety stock of drug to weather any potential disruptions and transport. Finally, we have no planned production runs during the first three quarters of the year and the manufacturing slots we've reserved for the fourth quarter and beyond remain in place.
From a regulatory perspective, we've received timely reviews of our submissions to FDA, EMA, and the national competent authorities covering our CTAs. With regard to clinical execution, while it's still early days, we have yet to encounter significant issues with our studies. In order to mitigate risk going forward, we've incorporated recent regulatory guidance that enable study start-up and ongoing patient accrual during the pandemic, while ensuring sufficient oversight of patient safety and data integrity. These efforts have included innovative approaches such as remote monitoring, patient transportation services, virtual clinic visits, and digital engagement with investigative site personnel. The key area of focus for us is site activation, where we do see individual clinics experiencing staffing constraints, limited availability of PPE and testing, and other institutional adjustments, such as the timing of IRB meetings. In the aggregate, these challenges have not resulted in a material impact to our expected timelines. We continue to monitor trial progress on a global scale and maintain close contact with our CROs, sites, and IRBs to ensure enrollment, activation, and data collection to keep pace in accordance with good clinical practice; so, active and effective engagement in a complex and evolving environment.
I'll now turn to our financials, the details of which are covered in the press release issued this morning. For the first quarter of 2020, we generated $13.3 million in revenue, nearly all of which came from non-cash royalty revenues. Operating expenses were approximately $37 million, comprised of $27.4 million in R&D expenses compared with $38.9 million for the first quarter of 2019. This $11.5 million decrease was driven by lower expenses, resulting from the restructuring of the business at the end of the second quarter of 2019, partially offset by greater clinical trial costs related to advancing our MIRASOL, SORAYA, and IMGN632 combination studies. G&A expenses were $8.9 million compared to $10.8 million in the first quarter of 2019, primarily due to lower personnel expenses resulting from the restructuring, partially offset by higher allocation of facility-related expenses for excess laboratory and office space. In addition, we incurred an $800,000 restructuring charge in the quarter.
As I mentioned earlier, we strengthened our cash position with an upsize follow-on offering that was completed in January, which added approximately $98 million in net proceeds to our balance sheet. With the addition of this raise, we ended the first quarter with $247.3 million in cash.
Our 2020 financial guidance remains unchanged. We continue to expect revenues to be between $60 million and $65 million, 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 and anticipated cash receipts from partners will fund operations into the second half of 2022.
With that, I'll turn the call over to Anna to review progress with our programs in more detail. Anna?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Thanks, Mark. I'll start by reiterating that all of our clinical studies essentially remain on track in large part due to the high unmet need across our patient populations and due to our rapid pivot to a more flexible approach to clinical trial execution, consistent with recent regulatory guidance. Wherever possible, we have converted to a remote model that allows us to continue activating sites for SORAYA, MIRASOL, and our IMGN632 program, enrolling patients across all studies and monitoring our clinical trials.
Turning to mirvetuximab, recall that late last year, we worked closely with FDA to define an accelerated pathway for approval of mirvetuximab via SORAYA, our pivotal single-arm study evaluating mirvetuximab monotherapy in approximately 110 women with platinum-resistant ovarian cancer, whose tumors are folate receptor alpha high as measured by PS2+ scoring and who have previously received Avastin. SORAYA could support accelerated approval for mirvetuximab provided that the overall response rate and duration of response surpassed those of the best available therapy at the time of regulatory action. As a reminder, the relevant overall response rate benchmark for currently available therapy is 12%, whereas for mirvetuximab, in 70 patients who were previously enrolled in our program and would have met the key eligibility criteria for SORAYA, we have demonstrated a 31.4% response rate.
I'm pleased to share SORAYA opened on time in the first quarter and we remain on track, expecting topline data in mid-2021, a BLA submission in the second half of 2021, and a potential approval in 2022.
In parallel, we continued to enroll patients and opened additional sites in MIRASOL, our confirmatory Phase 3 study, which began in December. Recall that 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 one-to-one to receive mirvetuximab or an investigator's choice of chemotherapy, namely paclitaxel, pegylated liposomal doxorubicin or topotecan. The primary endpoint is progression-free survival and the secondary endpoints are overall response rate, overall survival, and patient-reported outcomes. MIRASOL remains on track and we expect to report topline data for this study in the first half of 2022.
Regarding our mirvetuximab combination studies, we are pursuing doublet and triplet cohorts with carboplatin and bevacizumab in order to expand into earlier lines of treatment and provide longer duration of treatment. We continue to follow patients enrolled in both combinations and we look forward to presenting data from both studies later this year. At the upcoming virtual ASCO meeting on Friday, May 29, Dr. Lucy Gilbert will give an oral presentation of our initial efficacy and safety data from the FORWARD II platinum-agnostic doublet, evaluating mirvetuximab in combination with bevacizumab in 60 patients. These data will build on the encouraging MIRV, BEV data we previously generated in a separate platinum-resistant cohort and presented at ASCO last year, where we showed durable activity overall, and in particular, the efficacy measures observed for the AURELIA-matched subset with an overall response rate of 56% and a median progression-free survival of 9.9 months, which are compelling when considering outcomes reported for bevacizumab plus chemotherapy.
We also expect to present updated data with longer follow-ups from the platinum-sensitive triplet cohort, evaluating mirvetuximab in combination with carboplatin and bevacizumab in the fall. Lastly, we are delighted to support a new investigator-sponsored trial, evaluating mirvetuximab in combination with carboplatin. This is a randomized Phase 2 trial of over 100 patients, comparing mirvetuximab plus carboplatin, followed by mirvetuximab maintenance to standard platinum-based therapy followed by standard of care maintenance in recurrent platinum-sensitive disease.
Looking to our early stage portfolio, we have progressed three additional programs targeting a range of tumor types in both hematological malignancies and solid tumors. For IMGN632 monotherapy, we continued patient enrollment in Phase 1 expansion cohorts with a focus on BPDCN and minimal residual disease positive AML, following frontline induction therapy. We are also advancing IMGN632 combination studies with azacitidine, with venetoclax and as a triplet in relapsed-refractory AML patients and look forward to presenting data from each of these studies before the end of the year.
We have further progressed IND-enabling activities for IMGC936, our novel ADAM9-targeting ADC in co-development with MacroGenics. We anticipate the IND for 936 will be filed this quarter. Finally, we are advancing IMGN151, our next-generation ADC designed to more fully address the unmet needs of lower expressing folate receptor alpha tumor types. 151 incorporates several key design innovations, including a biparatopic antibody that recognizes two epitopes on FR alpha to enhance binding, a protease-cleavable linker with enhanced stability and longer half-life, and a next-generation maytansinoid, DM21, which along with the linker provides improved bystander killing. In preclinical models, IMGN151 shows improved activity in low and medium FR alpha-expressing tumors. We look forward to sharing the full preclinical data for 151 at the virtual AACR meeting in June.
With that, I'll turn the call back over to Mark.
Mark Enyedy -- President and Chief Executive Officer
Thanks, Anna. Just a few closing remarks before we open the call for questions. As we look to the year ahead, COVID-19 has no doubt created uncertainty and instability. I am, however, encouraged by the strength of our business and the determination of our people to continue moving forward to deliver more good days for patients with cancer. To that end, we've implemented contingency plans and a concerted effort to manage risk and position the business for success in a volatile environment. Our balance sheet is strong, providing us with cash runway well into 2022, and we will continue to execute on our strategic priorities. We have a number of important milestones in 2020, and I look forward to updating you on our progress throughout the remainder of the year.
With that, we'll open the call for questions. Operator?
Questions and Answers:
Operator
Thank you. [Operator Instructions] Our first question comes from John Newman with Canaccord. Your line is now open.
John Newman -- Canaccord Genuity -- Analyst
Hey guys, good morning. Thanks very much for taking my question, and I hope everybody is safe and sound out there in Boston.
Mark Enyedy -- President and Chief Executive Officer
Same to you.
John Newman -- Canaccord Genuity -- Analyst
First question I -- thank you. First question I've got on SORAYA and MIRASOL, definitely sounds like you've taken some steps to ensure that those studies proceed smoothly, but just wondered if you could talk about perhaps any flexibility that you've been able to build into the protocol. For example, are you able to allow any flexibility regarding the exact dosing date for an infusion? Maybe perhaps could you take any of the CT scans at alternate centers? And then on FORWARD II at ASCO, just curious if some of the patients that we would see data on would have previously received Avastin. Thanks.
Mark Enyedy -- President and Chief Executive Officer
Anna?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Thanks, John. So, regarding SORAYA and MIRASOL and the flexibility that we are employing as we're getting both of these studies fully up and running, we have taken measures as we can consistent with the regulatory guidances that have been put out both here and across the pond. Specifically, things that we have started to implement includes where possible allowing patients to consent remotely for the initial pre-screening for folate receptor alpha. You may recall patients need to have their tumor tissue sent for FR alpha and so they don't need to necessarily come into the sites to have the conversation and sign the paperwork for the inform -- consent form. That can be done remotely along with the site policies and procedures and the IRBs. So, I think that's a step that will allow us to keep up the momentum. We have always had some flexibility regarding the windows for dosing dates and CT scans really to allow for things like holidays or scheduling shift by a few days. More than that, we have not [Technical Issues] into the protocol. We really do need to make data integrity of the trial. That being said, if protocol deviations occur, they will be documented appropriately. Certainly for CT scans, they could be done at other local more easily accessible and lower risk sites. So, those are the things that we are building in and we're monitoring closely for that.
Pivoting toward your second question regarding Forward II and the data to be expected at ASCO, this is a cohort of 60 new patients, all of whom are receiving mirvetuximab and bevacizumab. Certainly some of them have received prior bevacizumab, but that was not a requirement for enrollment in the platinum-agnostic cohort.
John Newman -- Canaccord Genuity -- Analyst
Okay, great. Thank you.
Operator
Thank you. Our next question comes from Debjit Chattopadhyay with HC Wainwright. Your line is now open.
Earl DeSouza -- HC Wainwright & Co. -- Analyst
Hi, good morning. Hope everyone is healthy and safe. This is -- or this is Earl DeSouza in for Debjit. Can you hear me?
Mark Enyedy -- President and Chief Executive Officer
Yes. If you could speak up just a little bit, your voice is a little faint.
Earl DeSouza -- HC Wainwright & Co. -- Analyst
Got it. Can you hear me now?
Mark Enyedy -- President and Chief Executive Officer
Perfect.
Earl DeSouza -- HC Wainwright & Co. -- Analyst
Okay. So a couple of questions on upfront. As you explore the opportunity in platinum-agnostic cohorts, are you observing any marked changes in folate receptor alpha expression compared to later line patients, so, basically ones who have PARPs, BEV, taxanes-altered expression? And the second question that we have, will you continue to use the PS2 assay or would you consider an H-score for the new program? Thank you.
Mark Enyedy -- President and Chief Executive Officer
Yeah. So I'll give this a shot and then Anna, if you have any additional color, please jump in. So, the level of folate receptor alpha expression has been markedly uniform over lines of therapy irrespective of prior treatment. So what we have seen, we now have screened well over 2,000 samples in the program, is that about 40% of ovarian cancer patients express folate receptor alpha at high levels measured by the PS2+ assay, another 20% at medium levels, another 20% at low levels, and then the remaining 20% with negligible levels of expression. And as I say, that is true whether you're talking about earlier line patients, late-line patients, and it doesn't vary in terms of prior therapy; so, very consistent across the board. And for purposes of the screening for the program on a go-forward basis, we will be using the PS2+ scoring method to identify patients.
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
So, if I may add a little color. So the tumor tissue for our trials is based on archival tissue. And so, additional data that we have showing the stability of folate receptor alpha over time in lines of therapy come from other groups that have reported retrospective data as well as our biopsy cohort that showed greater than 70% concordance between archival tissue and fresh biopsies. So we do believe FR alpha expression is stable over time.
Regarding the PS2+ methodology versus the H-score, what I would say, I totally agree that -- with Mark that we are moving forward with the PS2+ methodology, but please understand that the pathologists score based on the percent of cells positive and the level of intensity. So the way they go about scoring is quite similar to the H-score. We have just validated the PS2+ cut off of at least 75% of sales, having at least 2+ staining intensity by IHC for inclusion in our trials moving forward.
Analyst
Thank you so much, guys.
Operator
Thank you. Our next question comes from Kennen MacKay with RBC Capital Markets. Your line is now open.
Kennen MacKay -- RBC Capital Markets -- Analyst
Hi, thanks so much for taking the question, and congrats on the operational progress despite this global pandemic here.
Mark Enyedy -- President and Chief Executive Officer
Thanks.
Kennen MacKay -- RBC Capital Markets -- Analyst
Looking forward to hearing quite a bit more on 151 at the now virtual AACR conference, but was hoping maybe you could talk a little bit more about the importance of the epitopes here on the folate receptor as well as the protease-cleavable linker and really how that stability and release differs from mirvetuximab, especially as it relates to potential early release of payload before actually binding and being brought into the cancer cells to deliver the payload. Thanks so much and congrats again.
Mark Enyedy -- President and Chief Executive Officer
Thanks. Anna?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah, sure. So, as you heard, 151 is our next-generation folate receptor alpha-targeted ADC and one of the key innovations that we have incorporated is that it is a biparatopic. So, that means that it binds two epitopes on folate receptor alpha. So that basically gives the antibody-drug conjugate more opportunities to bind FR alpha and therefore more opportunities to internalize. So we have preclinical data showing that this approach is quite effective, particularly for patients' tumors with lower levels of FR alpha expression. So that is a key innovation in 151.
The protease-cleavable linker also has some very attractive features in terms of improved stability. And then the payload itself is next-generation maytansinoid that is a bit more hydrophobic allowing for better bystander killing, again with the intent to really address the remaining unmet need in FR alpha positive tumors specifically that are positive, but at lower medium levels of expression. So that's what I can share now and the abstract will be released middle of May, I think May 15, and then the poster will be in mid-June at the next tranche of virtual AACR meeting.
Kennen MacKay -- RBC Capital Markets -- Analyst
And Anna, maybe just to elaborate on that, so does this enable potentially two antibodies to bind to the same receptor or is there some level of competitive inhibition despite being biparatopic like that?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
No, it wouldn't be competitive inhibition, Kennen, rather, you could have one ADC construct bind in two different locations or you could have two ADCs bind also in two different locations. So, there wouldn't be really competitive inhibition because both molecules are active, and the more binding there is, the more internalization. So more binding is better for internalization.
Kennen MacKay -- RBC Capital Markets -- Analyst
Got you. Thank you.
Operator
Thank you. Our next question comes from Andy Hsieh with William Blair. Your line is now open.
Andy T. Hsieh -- William Blair & Company -- Analyst
Great. Thanks for taking my question and hopefully the ImmunoGen team is staying safe and well. Kind of following up on Kennen's question, with a bivalent binding, I'm just wondering with this logic, do you expect potentially a cleaner safety profile? I'm just kind of thinking about the logic here having an and logic probably select for a smaller population of cell receptors to target. Is that a right way to think about that?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
So we've really designed 151 to address patients with lower levels of FR alpha expression on their tumors, retaining all the desirable features of ADCs in terms of targeting tumor tissue and sparing normal tissue. So, with that in mind, we're certainly in the process of doing the required safety studies that will be needed when we file the IND. Mirvetuximab itself has a very nice safety profile. The features of it that are unique in terms of the ocular really are not target-related, but rather payload-related in terms of any of these tubulin-directed payloads can cause the ocular. So I think there is a potential for the safety profile to be improved, but I think it's just early days, and once we have the non-clinical -- the tox data and then once we have clinical data, we'll really be able to stack it up, but really our focus is on creating another safe, well-tolerated ADC that can target a broader population with lower levels of FR alpha expression.
Andy T. Hsieh -- William Blair & Company -- Analyst
Okay, that makes sense. And in terms of the IST that you outlined, 100 patients targeting, I guess, in combination with carboplatin, just for the maintenance phase, is there a step duration or the treatment duration is pretty flexible? And kind of related to that, so for patients who discontinue in the "induction phase", could they continue again in the maintenance phase for that trial?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
So, this is an investigator-sponsored trial, led by Philipp Harter in Germany and it is in recurrent platinum-sensitive disease. So these patients we know are not going to be cured and when maintenance is given in this setting, it's generally given until progression. And so, for both arms of the trial, maintenance will be given really according to standard of care practice, so as long as patients are benefiting overall from the therapy. So there will be no difference across the arms in terms of duration of maintenance therapy, be it either mirvetuximab on an experimental basis or whatever standard of care maintenance option the physician chooses.
And I'm blanking, sorry, Andy on the second part of your question -- oh, if they stop in the induction phase. So...
Andy T. Hsieh -- William Blair & Company -- Analyst
Right.
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Typically, when you have recurrent platinum-sensitive disease, you -- assuming you have a healthy enough bone marrow and you don't have hypersensitivity reactions, you generally get between four cycles and eight cycles of carboplatin. So, as long as the patient has gotten a significant number of doublet cycles, then they can move on to mirvetuximab. And again, the treatment in both arms is going to be -- or the way physicians manage the carboplatin-based doublet is going to be the same across both arms and will be consistent with really how they just take care of patients as standard of care.
Andy T. Hsieh -- William Blair & Company -- Analyst
Great. Yeah, that's very interesting trial. And lastly, if you don't mind, I think you provided a lot of commentary regarding COVID-19 and contingency plans, so much appreciated. So, in terms of the assay development with partner, Ventana, obviously, a lot of the diagnostic companies are repurposing and kind of refocusing their corporate strategy, just wondering about the latest dialog with them in terms of kind of pushing through regulatory preparation.
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
We're on track with Ventana. They've done all the work to validate the assay. So that we've got it up and running in SORAYA and MIRASOL and we have very frequent meetings with them to plan ahead for the regulatory requirements and for commercialization. So, that remains on track.
Andy T. Hsieh -- William Blair & Company -- Analyst
Okay. Awesome. Well, thank you very much. Take care. And thanks for answering all my questions.
Mark Enyedy -- President and Chief Executive Officer
Sure.
Operator
Thank you. And our next question comes from John Newman with Canaccord. Your line is now open.
John Newman -- Canaccord Genuity -- Analyst
Hey, guys, thanks for taking additional question. Just wondering, if you could comment a bit about the competitive landscape for folate receptor alpha-targeted therapies. Obviously, you've had a lot of experience here. You have your own second-generation molecule in development. We've seen a number of other companies in the past that have faced pretty significant challenges. I think there's been some recent data that have surfaced, but just wondering if you could give us a sense as to how you envision things here. Obviously, you're quite late in development, but just curious as to how you think about the rest of the field. Thanks.
Mark Enyedy -- President and Chief Executive Officer
Yeah, I mean, just more broadly on the competitive situation and then I'll ask Anna to talk about some of the earlier-stage programs, but what we see in the first instance is the potential of the launch of mirvetuximab in 2022 into a relatively open field, and what I mean by that is, apart from the advances with the PARP inhibitors, which are predominantly focused in the frontline in recurrent platinum-sensitive setting, there is limited activity in terms of competitive programs in platinum-resistant disease. There's a number of trials ongoing, so I don't mean to diminish that, but in terms of near-term approvals, we think that mirvetuximab, with the benefit of the SORAYA outcome, will be the first new approval in platinum-resistant as initial therapy in some time. So we're comfortable in terms of where our competitive positioning lies with our initial program, and as we think about label expansion, what we see is mirvetuximab being complementary to the newer developments in recurrent platinum-sensitive disease. And so, our expectation is that given our ability to combine with other products as demonstrated by the data we've generated to-date and you'll see more of that at ASCO next -- actually later this month, we think we're in a very strong competitive position.
And then, as we think about some of these earlier-stage programs, Anna will give you some more detail as we've looked at, for example, the program from Sutro and also the work that Mersana is doing with NaPi2b. As you say, we're a lot further along in those programs. And our view is that those agents ultimately ought to be compared to what we're doing with 151 as we go forward, but let me let Anna to talk to you a little bit more about what we're seeing from the earlier-stage programs.
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah. Thanks, Mark. So, yeah I think the Sutro's FR alpha-targeted ADC is probably the most relevant at this point and Mersana has some data on their NaPi2b. There's also a couple of earlier FR alpha ADCs, Azaya has a naked antibody for elotuzumab that they hooked up to eribulin and [Indecipherable] has one in preclinical development. But focusing on Sutro, since they just shared some data at AACR, the four points that we're really looking at are dosing schedule, number one; safety, number two; efficacy, number 3; and patient selection, number 4. So, from a dosing schedule perspective, it seems that based on the safety profile they're seeing with some significant grade 3 and 4 neutropenia, they are trying to figure out what their optimal or the recommended Phase 2 dosing schedule is. They're exploring several different dose levels and not clear of Q3 or Q4 week is going to be the dosing schedule.
From a safety profile perspective, the neutropenia that they're seeing, while it hasn't resulted in any, febrile neutropenia could really pose a problem for longer-term plans in terms of combined ability. Mirvetuximab doesn't have any grade 3 or greater neutropenia as a monotherapy and that's one of the key features of mirvetuximab that has allowed us to combine full dose mirvetuximab with full dose of everything that we have combined with.
In terms of other safety features, mirvetuximab, we have low-grade manageable ocular adverse events and I would just note that when we did our initial IND-enabling GLP tox studies, we did not see any ocular adverse events in the snow monkeys. So, not clear to me how predictive that negative is for them.
So, moving to efficacy, they certainly have shown some CA 125 drops in patients and they have one partial response I believe in around 20 patients. And for a Phase 1 dose escalation program, this is pretty consistent with what we had seen previously. And it's early signs that there is some activity, but I would just point out that CA 125 responses by themselves really are not sufficient for regulatory approval. And I would also point out that as they're thinking about patient selection, we've done a lot of work on patient selection to figure out which patients benefit most from mirvetuximab, and being able to have a sufficient data set with a sufficient number of responses to guide that is going to be really important and certainly they've showed some stable disease, but it's really not clear what their tumor shrinkage is and how much antitumor activity they're seeing other than what they've demonstrated with their CA 125 responses [Indecipherable]. Early days for Sutro, certainly, we were there, and we're going to continue to follow their developments.
I would say that our next-generation FR alpha-targeted agent, IMGN151 with the biparatopic targeting of FR alpha, really is going to be something for us to think about as we benchmark sort of the next-generation of FR alpha compound.
And then pivoting to Mersana, earlier this year, they've presented data in under-40 patients again. They have seen some activity with some partial responses. They are having -- they're selecting patients or figuring out their patient selection strategy as well. They are taking an approach with a high DAR and that could have some potential issues if the further [Phonetic] hypothesis really continues to show evidence that if you have a very, very potent -- lots and lots payloads, you may have trouble penetrating tumors. So, stay tuned, and we're excited about mirvetuximab. We're in Phase 3. We've got two trials set up now, so that we hopefully will get accelerated approval, followed by confirmatory trial, and we have a nice data that we'll share at ASCO for MIRV plus BEV that should support compendia listing.
John Newman -- Canaccord Genuity -- Analyst
And so if I might ask one additional quick question, given what we know about targeting folate receptor alpha across multiple tumor types, is there a possibility that at some point in time, the 151 molecule could be tested perhaps in something like lung cancer or would you probably stick to...
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Absolutely. Lung cancer, triple-negative breast cancer, endometrial cancer, you bet, John.
John Newman -- Canaccord Genuity -- Analyst
Yeah. Okay, super. Thank you.
Operator
Thank you. [Operator Instructions] Our first -- our next question comes from Boris Peaker with Cowen. Your line is now open.
Mark Enyedy -- President and Chief Executive Officer
Boris?
Operator
If your line is muted, please unmute. And our next question comes from Biren Amin with Jefferies. Your line is now open.
Biren Amin -- Jefferies & Company, Inc. -- Analyst
Yeah. Hey guys, thanks for taking the question. I hope you guys are doing well.
Mark Enyedy -- President and Chief Executive Officer
Thanks.
Biren Amin -- Jefferies & Company, Inc. -- Analyst
On MIRV, I wanted to ask on the triplet in platinum-sensitive with BEV and carboplatin, I think you had data last year at ESMO. Just wanted to see when we can expect an update from that trial and what are your thoughts on moving forward in the setting, given the IST also with the doublet now as well?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah. So we're planning to submit an abstract to ESMO with updated data for the triplet. You may recall, last year was the first reveal of the data and we had response rate data, but we didn't have sufficient follow-up for duration and so now we do and we will share that data at ESMO. So then, thinking about future plans, I would say once we're able to share the data with the MIRV-BEV doublet from the platinum-agnostic cohort at ASCO, it will be clear that we do have several options to move forward in earlier lines of therapy with longer durations both in MIRV-BEV combination and the triplet. So, I think that's where I'll leave it at this point. I don't know Mark, if you want to add anything.
Mark Enyedy -- President and Chief Executive Officer
No, I think you've covered it nicely. Thanks.
Biren Amin -- Jefferies & Company, Inc. -- Analyst
All right. And then maybe a second question on IMGC936. I think you're planning on filing an IND in the second quarter -- later this quarter. So is the plan to start the Phase 1 later this year and you're using a different payload, I think you're using DM21 versus DM4, so, given your comments earlier on sino model not a good predictor for ocular tox, how do you think about ocular tox with that payload? And then, I guess, for the Phase 1, would you look at using a diagnostic, an ADAM9 diagnostic, given you've got certain solid tumors where it's highly expressed like panc, gastric, and colorectal? And are those the tumors that you're going after in the Phase 1?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah. So, for IMGC936, which targets ADAM9, we are using DM21 and I think it's again early days. Certainly we have learned a lot in the mirvetuximab program in terms of optimizing management of corneal keratopathy should it occur. So, I think we'll be able to get ahead of it if it does occur, but right now we have no data that suggests that it will or won't occur, but if it does, we're prepared.
And then moving toward patient selection, ADAM9 is expressed. It's a member of the matrix metalloproteinase family and it's expressed on a wide variety of tumors, as you mentioned, and spared relatively on normal cells and we do anticipate that potentially we may need to select patients based on 936 expression. And so, we are well positioned to do that should we need to when we do plan to incorporate the appropriate activities in the Phase 1 trial to gather data to support efforts for patient selection if we need it. And early on, we'll be targeting four tumor types in the Phase 1 trial. As you mentioned, we'll be going after gastric, pancreatic, triple-negative breast, and lung, and then we'll see. We'll follow the science and we'll go after the tumor types where we're really demonstrating nice activity and a good safety profile.
Biren Amin -- Jefferies & Company, Inc. -- Analyst
Great, thank you.
Mark Enyedy -- President and Chief Executive Officer
Sure.
Operator
Thank you. Our next question comes from Jonathan Chang with SVB Leerink. Your line is now open.
David Ruch -- SVB Leerink -- Analyst
Hey guys, this is David Ruch on for Jonathan. Thanks for taking our questions. Just with regard to the ASCO patient population, how much detail can we expect on the population in terms of prior therapy? I know someone previously had asked about prior Avastin, but what do you expect in terms of prior PARPs?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah. So, we will share demographic data from this population. Not surprisingly, over time, as you look back at all of the cohorts we have enrolled, the percent of patients who have a prior PARP is increasing. So, we'll share the data this -- this is a platinum-agnostic cohort, so we'll share details around the percent of patients who are considered platinum-resistant versus platinum-sensitive and give a sense of how platinum-sensitive they are. We'll share percent of patients with prior BEV, with prior PARP, certainly prior taxanes. So, you'll get a good feel of the population.
David Ruch -- SVB Leerink -- Analyst
Great, thank you. And if the ASCO data are promising or encouraging, what does the regulatory path forward look like in the platinum-agnostic setting and what studies would you point to as benchmarks for efficacy in this patient population?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah. So, certainly from a regulatory perspective, the most conservative approach could be for us say a randomized trial from MIRV-BEV versus MIRV-chemo and the benchmark for MIRV-chemo is a pretty underwhelming 27% response rate and median PFS of 6.7 months, specifically in platinum-resistant disease. I think going into a broader population that includes platinum-sensitive patients would require dialog with FDA and certainly, the recent approvals in ovarian cancer in patients who've had a number of lines of prior therapy regardless of their platinum sensitivity suggests that we could have productive conversations with FDA in that regard.
In terms of the benchmark for non-platinum doublets in platinum-sensitive disease, there really aren't a lot, but the one that I've been starting to look at from a European perspective is trabectedin or yondelis. It was approved in combination with Doxil, having beaten single agent Doxil in platinum-sensitive patients. That was a subset from the Phase 3 trial and so it wasn't sufficient for approval in the US, but for our purposes, from an efficacy benchmarking perspective, the MIRV-BEV combination is quite encouraging.
So, I think certainly there is more work for us to do longer in terms of figuring out which of the regulatory options is most favorable for us. And in the short-term, we've now generated data in two separate cohorts from the MIRV-BEV combination that we believe are robust enough and sufficient to support compendia listing that should be available right around the time that we get our initial MIRV monotherapy approval, so that physicians in the US will have the option to use either MIRV monotherapy or MRIV plus BEV in their patients with platinum-resistant disease.
David Ruch -- SVB Leerink -- Analyst
Got it, thanks. And then just one more clarification, with regards to 632, you mentioned an update later this year, is that still expected to be ASH?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yes.
David Ruch -- SVB Leerink -- Analyst
And could you give some color on the -- OK, great. And then any color on your expectations for durability, duration of response data and what kind of -- what's the patient population that you would be most -- highlighting the most as far as something for next steps regulatory wise?
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah. So IMGN632 is our CD123-targeted ADC with our potent IGN payload and we are developing it as a monotherapy for blastic plasmacytoid dendritic cell neoplasm and also as a monotherapy for AML patients with minimal residual disease after frontline induction therapy. We are also developing it in combination with azacitidine, with venetoclax, and as a triplet. And those are currently in dose escalation and moving along. So, we would anticipate sharing all the data we have from this program at ASH and our -- we continue to remain focused on gathering sufficient data in BPDCN, where there is a high unmet need to allow us to engage in the -- with the regulatory authorities on a path for approval there, while we are continuing to progress it also in monotherapy for MRD-positive disease and in combination.
David Ruch -- SVB Leerink -- Analyst
Got it. Thank you so much.
Operator
Thank you. Our next question comes from Michael Schmidt with Guggenheim. Your line is now open.
Michael Schmidt -- Guggenheim Securities -- Analyst
Hey guys, thanks for taking my questions. Just maybe a high-level question around 151. I guess, how do you balance, I guess, investment into mirvetuximab longer term as well as 151? I mean, do you see 151 eventually replacing mirvetuximab? Or is there -- are there alternative indications or patient populations where you could see both -- 151 succeeding and both drugs, I guess, maintain relevance so to speak?
Mark Enyedy -- President and Chief Executive Officer
Yeah. So priority one, Michael, is to get mirvetuximab approved. Given the data that we've generated, the focus of that molecule should be on patients with high levels of expression. And we got a pretty robust program today in terms of securing the initial approval based on SORAYA expanding to full approval and then adding combinations to expand the patient populations into earlier lines of therapy. And so, we expect that program to roll out and those data to unfold over the next -- securing an approval -- initial approval in 2022, the readout of MIRASOL in the first half and then moving to full approval and then having the combination data come online. But again, all focused on patients with FR alpha high levels of expression.
And so, as we think about 151, the goal there was to engineer something that could address lower levels of expression, both to address a broader segment of ovarian cancer, but also as was pointed out to one of the earlier questions, to move into additional tumor types, endometrial, triple-negative lung, etc. And so, I think our -- the initial focus for 151 will be in those segments of the market not addressable by mirvetuximab. And then as time goes by, we can look at potential complementarity or ultimately whether the data tell us that cannibalization is what's going to happen here, but I think we're very long way away from that and the potential opportunity for 151 is sufficiently distinct at this point to allow us to develop them in non-overlapping indications.
Michael Schmidt -- Guggenheim Securities -- Analyst
Got it, thanks. And then just on 151, maybe just -- if you could just comment a bit more on the choice of the payload. I think I heard you say the payload is a maytansinoid derivative. So maybe just talk about the choice of that as opposed to, for example, using one of your [Indecipherable]?
Mark Enyedy -- President and Chief Executive Officer
Yeah. So, there is a couple of points to make here. One is, we talked a little bit about this, but the stability of the linker, so this is a linker that's made up of three alanine residues and the middle alanine is a D isomer. So that's -- you don't normally find that in nature and so it makes it very resistant to serum proteases and so, from our perspective that gave enhanced stability. In terms of the engineering to the payload, we looked at the IGN. So, one of the things that was a hallmark of the research organization here was to examine multiple payloads, and when we looked at therapeutic index, where we were going with this DM21 payload more broadly. So, we're using it in the 936 program, we used it in the EpCAM program that we licensed to CytomX and also to -- as part of 151. And so, the MedChem exercise here was really built around adjusting the carbon atoms relative to DM4 to improve the hydrophobicity, which gave us better bystander killing. There is also some work that's done in terms of the cleavage in the lysosome to also improve those properties. And so, altogether, we've got a very nice payload and a stable linker attached to it, which we think is going to give us a significant improvement in these lower levels of folate receptor alpha expression.
Michael Schmidt -- Guggenheim Securities -- Analyst
Great. Thank you, Mark, and congrats on the progress and keeping everything up and running.
Mark Enyedy -- President and Chief Executive Officer
Thanks.
Operator
Thank you. Our next question comes from Jessica Fye with JP Morgan. Your line is now open.
Jessica Fye -- JP Morgan Securities -- Analyst
Hey guys, good morning. Thanks for taking my questions. I guess, two -- hey, Mark. Maybe first on 632, when we think about the AML MRD-positive setting, can you lay out what the efficacy bar is in that setting, what you want to see in that data later this year? And then second on the financial side, when you talk about anticipated cash receipts from partners, can you give us a bit of a framework for how to think about the size and timing of those potential payments, for example, how much if any is baked into the 2020 guidance? Thank you.
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah. So...
Mark Enyedy -- President and Chief Executive Officer
Sure. Anna, you want to cover AML, yeah.
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah.
Mark Enyedy -- President and Chief Executive Officer
Okay, good.
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
Yeah. So, Jess, the MRD-positive cohorts, this is taking patients who are in a complete response and so, they have less than 5% blasts in their marrow, but they have minimal residual disease and its detectable by either PCR or flow and we want to basically see conversion from MRD positivity to MRD negativity, because we know really the lower the blast count, the better patients do, and we know that MRD positivity bodes poorly for patients. The recently completed randomized Phase 3 trial of oral azacitidine or CC-486 versus placebo will be a helpful benchmark for us. Now it was slightly different because they took all patients after completion of their initial induction therapy and then randomized them. So they didn't specifically focus on the MRD-positive cohort, they took everybody. And so that is going to be a helpful benchmark for us. But right now, really from a proof of concept perspective is, we would like to see a reasonable percentage of patients convert from MRD-positive to MRD-negative within a few cycles of IMGN632.
I don't think we're ready at this point to say, oh, this is our go-no-go criterion, but I think between understanding the oral azacitidine data and then looking at the percent of patients who'd get to MRD negativity and the tempo of that that should help guide us regarding next steps.
Just as a note of caution, conversion from MRD positivity to MRD negativity in itself does not have a regulatory precedent in AML, but if our data are quite encouraging, obviously, we will engage the regulators on the path forward for registration for this indication.
Mark Enyedy -- President and Chief Executive Officer
Great. So, just on the cash piece, there are really two components built into the partnering elements of it, one of which relates to milestone payments from our legacy partnering deals, whether it's Roche, Novartis, etc., and some of the newer deals. In fact, CytomX, we just earned a milestone there. And so there is an element of that and then there is a separate component related to active partnering discussions. We have inbound interest for a partnership in China. And so, we have assumed in 2020 that we will get our partnering deal done for mirvetuximab in China, and so, both of those components are built into the cash forecast. I guess, what I would say is we don't -- we won't break those elements out separately in part for competitive reasons as we think about negotiating upfront fees with potential partners in China. What I would say is, we've got a pretty strong track record here of completing the deals that we put in scope as a business certainly over the last couple of years. And so, we won't -- we don't put those numbers in unless we have a reasonable degree of confidence that we can affect those deals.
Jessica Fye -- JP Morgan Securities -- Analyst
Great, thank you.
Mark Enyedy -- President and Chief Executive Officer
Sure.
Operator
Thank you. I'm not showing any further questions at this time. I would now like to turn the call back over to Mark Enyedy for closing remarks.
Mark Enyedy -- President and Chief Executive Officer
Great. Well, thank you all for joining us this morning. I hope you and your families are safe and well, and we look forward to emerging from this and continuing to report out our progress, in particular looking very much forward to the ASCO presentation and also the AACR poster. So, thanks very much, and look forward to talking again soon.
Operator
[Operator Closing Remarks]
Duration: 58 minutes
Call participants:
Courtney O'Konek -- Senior Director of Corporate Communications and Investor Relations
Mark Enyedy -- President and Chief Executive Officer
Anna Berkenblit -- Senior Vice President, Chief Medical Officer
John Newman -- Canaccord Genuity -- Analyst
Earl DeSouza -- HC Wainwright & Co. -- Analyst
Analyst
Kennen MacKay -- RBC Capital Markets -- Analyst
Andy T. Hsieh -- William Blair & Company -- Analyst
Biren Amin -- Jefferies & Company, Inc. -- Analyst
David Ruch -- SVB Leerink -- Analyst
Michael Schmidt -- Guggenheim Securities -- Analyst
Jessica Fye -- JP Morgan Securities -- Analyst
