Nov 2, 2018
Executives
Sarah Kiely - Investor Relations and Corporate Communications Mark Enyedy - President and CEO Anna Berkenblit - Chief Medical Officer Dave Johnston - Chief Financial Officer Rich Gregory - Chief Scientific Officer
Analysts
Yige Guo - Guggenheim Partners Jonathan Chang - Leerink Partners Debjit Chattopadhyay - H.C. Wainwright John Newman - Canaccord Andy Hsieh - William Blair Kennen MacKay - RBC Capital Markets Jessica Fye - JPMorgan Boris Peaker - Cowen Joseph Catanzaro - Piper Jaffray
Operator
Good day, and welcome, everyone, to this ImmunoGen Third Quarter 2018 Financial Results Conference Call. Today's call is being recorded.
At this time, for opening remarks and introductions, I would like to turn the call over to Sarah Kiely, Investor Relations and Corporate Communications. Please go ahead.
Sarah Kiely
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 third quarter 2018 operating results.
This press release and the recording of the call can be found under the Investors and Media section of our website at immunogen.com. On the call today are our President and CEO, Mark Enyedy; our Chief Medical Officer, Anna Berkenblit; and our CFO, Dave Johnston.
Rich Gregory, our Chief Scientific Officer, will join the team for the Q&A session. During today's call, we will highlight key recent accomplishments and review third quarter 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.
With that, I'll now turn the call over to Mark.
Mark Enyedy
Thank you, Sarah. Good morning, everyone, and thank you for joining us today.
With the completion of enrollment in our pivotal FORWARD I study, ImmunoGen entered the next stage in our transition to a fully integrated biopharmaceutical company. In particular, during the third quarter, we initiated the activities required to support a BLA filling and launch mirvetuximab to treat patients with platinum-resistant ovarian cancer.
These efforts have included completing the product validation runs for drug substance with drug product anticipated for stability testing before year end, establishing the operational metrics and resources necessary to ensure timely readout on the primary end point of FORWARD I, and moving ahead with prelaunch commercial planning to drive market uptake post approval. In parallel, we continue to execute towards our other strategic objectives.
Beyond the anticipated monotherapy indication, we planned to position mirvetuximab as a preferred partner for combination therapy and ovarian and other cancers. Last month, we presented favorable tolerability and encouraging anti-tumor activity from the FORWARD II expansion cohort of mirvetuximab in combination with Merck’s anti-PD-1 therapy, KEYTRUDA, and platinum-resistant disease at ESMO.
With these latest results in hand, we have now reported data this year of more than 100 patients who have received mirvetuximab in combination with Avastin carboplatin or KEYTRUDA. Our investigator community has expressed a high degree of enthusiasm for these mirvetuximab combinations, and we will use their input and our data to guide the next steps to expand the label from mirvetuximab in multiple treatment settings.
We were also evaluating our novel IGN ADCs, IMGN779 and IMGN632 in patients with hematological malignancies. Data from both of these Phase I programs have been accepted for oral presentations at ASH, next month, and preclinical data from 632 will also be presented during post-recession at the meeting.
Looking beyond our clinical assets, we are making rapid progress with our research portfolio. We have initiated IND-enabling activities for IMGC936, our novel ADAM9-targeting ADC program being developed in collaboration with MacroGenics.
ADAM9 is expressed on a range of solid tumors, including non-small cell lung, triple negative breast, gastric and pancreatic cancers, and we expect this program to be the next product candidate that we advance into the clinic. In addition, we presented preclinical data relating to our epithelial cell adhesion molecule, EpCAM-targeting Probody drug conjugate at the European Antibody Congress in October.
This EpCAM-targeting PDC, integrated CytomX's PROBODY technology, which enables the selection of targets previously thought to be in compatible with ADC development due to high normal tissue expression. We look forward to sharing more details on this program as it advances.
So significant progress with the business over the last quarter, and an exciting moment in ImmunoGen's evolution as we prepare for our pivotal readout in the first half of 2019. With that, I’ll turn the call over to Anna to review our clinical progress in more detail.
Anna?
Anna Berkenblit
Thank you, Mark. In addition to our primary objective of bringing mirvetuximab to market as a single agent therapy for women with platinum-resistant ovarian cancer, we are evaluating mirvetuximab combination regimens in our FORWARD II study to expand the eligible patient population and move mirvetuximab into earlier lines of treatment for ovarian cancer.
As a reminder, FORWARD II is our Phase Ib2 study of mirvetuximab in combination with Avastin or KEYTRUDA, in patients with folate receptor alpha positive platinum-resistant ovarian cancer. As part of FORWARD II, we are also enrolling a triplet combination cohort of mirvetuximab plus carboplatin and Avastin in patients with recurrent platinum-sensitive ovarian cancer.
We're making excellent progress with the triplet cohort and expect to complete enrollment of this cohort by the end of the year with initial data in mid-2019. Earlier this year, at ASCO, we reported data demonstrating encouraging activity from the expansion cohort evaluating mirvetuximab in combination with Avastin in over 50 patients with folate receptor alpha positive platinum resistant ovarian cancer.
Based on these promising results, we are planning to initiate a new expansion cohort in the FORWARD II study to evaluate mirvetuximab plus Avastin further in patients with recurrent ovarian cancer. We expect to open this cohort in the first quarter of 2019.
Most recently, at ESMO this October, we presented initial safety data and encouraging preliminary anti-tumor activity from the FORWARD II expansion cohort assessing mirvetuximab in combination with KEYTRUDA. The goal of this evaluation is to prolong the clinical benefit of the ADC in later-line patients through contaminant activation of the immune system.
Checkpoint inhibitors haven't done much in ovarian cancer as monotherapy with response rates around 10% to 15%, but for those patients who do respond, the response can be quite durable. So the idea here is to harness emerged like response and see if the addition of KEYTRUDA as anything to the durability of the clinical response.
Initial activity findings showed that 83% of patients experienced tumor shrinkage of target lesions in response to treatment with mirvetuximab and KEYTRUDA with more robust reductions observed in patients with medium or high folate receptor alpha expressions. The initial anti-tumor activity recorded is consistent with the broader mirvetuximab monotherapy experience in heavily pretreated platinum-resistant ovarian cancer patients, and encouraging when considering outcomes reported for other KEYTRUDA based combinations evaluated to date in platinum-resistant ovarian cancer.
Notably, the confirmed overall response rate in this heavily pretreated population of platinum-resistant ovarian cancer in FORWARD II compared favorably to that observed for other KEYTRUDA combinations in less heavily pretreated platinum-resistant patients where published response rates have been below 20%. There was also a suggestion that in patients with a response to mirvetuximab plus KEYTRUDA, the duration of response maybe longer with the combination than what would be expected with mirvetuximab alone in this heavily pretreated population.
The mirvetuximab plus KEYTRUDA combination continues to demonstrate favorable tolerability consistent with the known safety profiles of each agent. As this cohort continues to mature, we will use data from it to guide further development of this novel combination as part of our broader strategy to establish mirvetuximab as the preferred combination therapy in ovarian cancer.
We look forward to sharing updated data from this cohort when the data armature. In addition to FORWARD II, we will remain on track for the topline readout from our Phase III FORWARD I registration trial of mirvetuximab as a single agent for platinum-resistant ovarian cancer in the first half of 2019.
As a reminder, the primary endpoint in FORWARD I is progression-free survival in the entire study population, which includes patients with both folate receptor alpha medium and high expression, as well as in the subset of patients with high folate receptor alpha expression. Based on the encouraging and consistent safety and activity profiles observed in clinical studies to date, we believe that mirvetuximab has the potential to displace chemotherapy as a single-agent treatment in the platinum-resistant setting and also to combine well with multiple agents facilitating label expansion in additional treatment setting.
Turning now to our him-focused ADCs, at ASH, next month, we will have two oral presentations, one from our Phase I dose finding study of IMGN779 targeting CD33 in patients with acute myeloid leukemia, or AML, and the second one with initial data from our Phase I dose finding study of IMGN632 targeting CD123 positive AML and blastic plasmacytoid dendritic cell neoplasm, or BPDCN. IMGN779 and IMGN632 are the first clinical assets from our new IGN pipeline.
As a reminder, our IGNs are novel class of DNA-acting payloads that we are developing. We've demonstrated preclinically that they are as active in terms of killing tumor cells as other DNA-acting agents that crosslink, for example, PBDs.
But because the IGNs alkylate or damage one strand of DNA, it is easier for normal cell to repair this damage. And therefore there is a potential for a better therapeutic window, the ability to repeat dose and to dose higher.
We believe these programs have strong potential in a range of hematologic malignancies, and the FDA recently granted orphan drug status to IMGN632 for the treatment of AML, we are encouraged by what we have seen thus far with IMIGN779 and IMGN632, and look forward to updating you at ASH next month. Now, I’ll turn the call over to Dave, to review our financials.
Dave Johnston
Thanks, Anna. Our financial results were detailed in this morning's press release, so I’ll review just the highlights.
We ended the third quarter with approximately $303 million in cash and cash equivalents, which we expect to fund our operations at least a year beyond the top line FORWARD I readout, which is expected in the first half of 2019. Revenues for the third quarter were approximately $11 million, which were largely noncash related to the Kadcyla royalty.
Operating expenses in the third quarter were $56.5 million, which included approximately $47 million in R&D expenses that were driven by mirvetuximab clinical trial costs in pre-commercial activities. We have updated our cash and revenue guidance as a result of licensing revenue that we now expect in 2019.
We now expect revenues to be between $50 and $55 million, and cash and cash equivalents at year end to be between $250 million and $255 million. This change has no impact on our projected cash runway.
Guidance remains unchanged for 2018 operating expenses, which we expect to be between $215 million and $220 million. We continue to operate with financial discipline focusing our resources on our top strategic objective, which is advancing mirvetuximab FORWARD towards the market.
So with that, let me now hand the call back over to Mark.
Mark Enyedy
Thanks Dave. It's been an exciting and productive year so far at ImmunoGen.
We have a number of upcoming milestones and activities in the fourth quarter and heading into 2019. ImmunoGen today is well positioned to execute on its strategic priorities and we look forward to providing additional updates on our clinical programs and commercial planning activities in the coming month.
With that, we'll open the line for questions.
Operator
Thank you. [Operator Instructions] We will now take our first question from Michael Schmidt of Guggenheim Partners.
Please go ahead.
Yige Guo
Yige Guo
Anna Berkenblit
So regarding dose response, as we mentioned in the abstract, we had 12 patients over four dose escalation cohorts, and we had four with an objective response. Since then, the study has continued to dose escalate and we will present all of the safety efficacy and PK data that we have at ASH in an oral presentation.
So we're quite encouraged with the data that we have thus far. Regarding your broader question about development strategy for both compounds, at this point, we are quite encouraged about both 779 and 632.
Our primary goal in the near-term is to identify the dose and schedule for each of these compounds in terms of monotherapy, and then consider combination strategies. AML has a high unmet need both in the initial settings and then in the relapsed and refractory setting.
And so we are thinking quite carefully with our partner at Jazz around how to develop both of these compounds in AML, and when we have identified the dosing schedule for monotherapy, and have initial safety data for combinations, we will be able to nail down a combination strategy and monotherapy strategy for both of these in AML.
Operator
[Operator Instructions] We will now take our next question from Jonathan Chang of Leerink Partners. Please go ahead.
Jonathan Chang
Good morning. Thanks for taking my questions.
First question, can you help set investor expectations with regards to how much more data we could see in the ASH presentations versus what was disclosed in the abstracts for both 779 and 632?
Anna Berkenblit
Sure. So both of these abstracts were submitted to ASH around the end of July this year, and these are based on two ongoing dose escalation studies.
These are three plus three studies. And each cycle, you need to get through one -- the first cycle to assess each cohort for safety from a dose limiting toxicity perspective.
So, IMGN779, the cycles are essentially four weeks, because we are dosing on a weekly schedule and then every other week schedule, and for IMGN632, the cycles are on a queue three week schedule. Both studies are still open and enrolling.
So therefore, you can kind of figure out that we will have additional patient data at ASH for both of these compounds.
Jonathan Chang
Great, thanks. And just as a follow-up to the ASH presentation.
How are you thinking about the CD123 competitive landscape with data from other early stage CD122 programs expected at ASH? What will you guys will be looking for in the competitor datasets?
Anna Berkenblit
Right. So the competitors are basically in a couple of different camps, the buy specifics and the car keys.
And right now we are the only ADC that I am aware of, targeting CD123, actively in the clinic. And so, from my perspective, each of these strategies has potential strengths and weaknesses, the buy specifics, they have demonstrated some anti-tumor activity.
They also have cytokine-release syndrome as a potential concern. So, I think the safety profile of those as they dose-escalated going to be important.
The CAR-Ts also, while that can be quite effective, they do require a patient to be healthy enough to receive the CAR-T, and be able to -- be stable enough to get the CAR-T. And so I don’t think that each of these strategies is going to be appropriate for all AML patients.
The potential advantage of well tolerated anti-body drug conjugate like the ones that we’re developing is that, once the patient is stabilized, it could be given as an outpatient in the clinic, once every three or four weeks, and that could really have an advantage from a patient tolerability perspective. So it's clear, at least, for – well, for those targets, CD33 and CD123, they're validated targets, and I think there’s a variety of strategies to address the unmet needs.
Jonathan Chang
Right. Thank you.
And just one more if I may, for mirvetuximab. Can you talk about your thoughts on how much the FORWARD II KEYTRUDA combination data could evolve with longer follow-up?
Thank you.
Anna Berkenblit
So, the question is really around durability of our thoughts. And in terms of how much the data could evolve with longer follow-up it's really about the tail, the curve.
And so I think, it's going to take us several more months, so into 2019, before we have a sense of whether or not the patients with confirmed responses have durable responses, and also for patients with stable disease who don’t technically meet the criteria for confirmed response by resist, also stay on study drug much longer than would have been expected with single-agent chemotherapy or even with mirvetuximab monotherapy. So, I think, in 2019, we’ll be able to make some decisions about further steps for that combination.
Operator
We will now take our next question from Debjit Chattopadhyay of H.C. Wainwright.
Please go ahead.
Debjit Chattopadhyay
Hey, good morning, and thank you for taking the questions. Just to confirm, you did mention in the prepared remarks on new study with mirvetuximab plus Avastin and recurrent ovarian cancer.
Should we understand that this is specifically focused on platinum sensitive patients?
Anna Berkenblit
So the next cohort combining mirvetuximab with Avastin will be in previously treated patients. The initial cohort showed very nice activity and safety in patients who meet our classical platinum-resistant criteria.
However, we know that the ovarian cancer landscape is evolving with addition of PARPs as maintenance, which is prolonging the platinum-free interval by sort of tagging along at the end the PARP. And while there are potential cross resistance mechanisms, it's going to make it difficult down the road to exactly pin down who is a platinum-resistant patient.
And therefore, our next cohort will really focus on bit of a broader population of patients who have already seen platinum who very well likely will have seen apart and are appropriate for an Avastin-based combination regimen that does not contain a platinum. So the criteria will be looser, if you will, than our initial cohort.
And therefore, we hope that the data that we generate from the second cohort will be generalizable to the future ovarian cancer population's needs.
Debjit Chattopadhyay
Thank you. And then, as you start thinking about the KEYTRUDA combination cohort, and assuming that you see durability of response on -- north of the 8 months kind of threshold, when do you start to -- and maybe you started thinking about platinum sensitive patients, because obviously, these patients are probably less speed up.
So from immune landscape kind of perspective, these patients are probably going to do better off. So from a positioning perspective, when you start thinking about platinum sensitive patients, when you reach out to the agency with the material data, and how do you position the KEYTRUDA combo?
Is it in later lines of therapy? Or do you move this upfront?
Thank you so much.
Anna Berkenblit
Thank you, Debjit. Yes, I think, what you're referring to is there is a though that immunotherapy, particularly, in ovarian cancer could work better in earlier lines of therapy when patients have more of an intact immune system and are a little bit less beat up from prior lines of cytotoxic chemotherapy.
So there is definitely interest in moving up checkpoint inhibitors into earlier lines of therapy in ovarian cancer. And certainly, there are many trials ongoing now that will read out in the coming years.
So I think, there's a couple of strategies that we could take. The initial proof of concept data if you will, that we're generating in later line patients with mirvetuximab plus pembrolizumab, if it continues to hold up to be really the best combination regimen with a checkpoint inhibitor in platinum-resistance disease, we will proceed with potential further development opportunities there.
Moving up into the platinum sensitive space, I think, would require a triplet, actually, of carboplatin plus mirvetuximab plus pembrolizumab. Certainly, in lung cancer, that type of strategy has been quite successful with pembrolizumab of carboplatin and pemetrexed as well as other triplets of two sided toxics plus checkpoint inhibitor.
So, at this point, our focus is on completing enrollment in the ongoing triplet of carboplatin, mirvetuximab and Avastin. And I think, it will be a good problem for us to have to have two very active triplets in the platinum-sensitive space.
We're not there yet. But that is one potential outcome if our mirvetuximab plus pembrolizumab data continue to be encouraging from a durability perspective.
Operator
We will now take our next question from John Newman of Canaccord. Please go ahead.
John Newman
Just had two questions. So, Anna, in the new Avastin cohort, would there be any different criteria regarding prior exposure to Avastin?
I can recall you may have had a few patients in the original Avastin cohorts that have been dosed previously. And the second question is on 779.
Just curious if, at this point, you are satisfied with the dose range and you’ll look to maybe narrow down the dose if you take forward? Or do you think that there is still some additional room to go on the dose escalation there?
Thanks.
Anna Berkenblit
Yes. So the first question about higher Avastin.
In the cohort that we -- in the dataset that we presented at ASCO this past year, we did have patients who had prior Avastin and we had patients who were Avastin naive. And it doesn't really look like prior Avastin matters.
Certainly, in the platinum-sensitive setting, the MITO/MaNGO study that was presented showed that prior Avastin doesn’t limit the impact of a subsequent Avastin containing regimen. So, philosophically, we are moving forward with that strategy allowing patients with prior Avastin to enroll in our upcoming new mirvetuximab plus Avastin cohort, because we believe that patients will continue to get benefit with retreatment with Avastin.
Moving to your second question about 779, and whether or not we’re satisfied with the dose range, what I can tell you is 779 is still in dose escalation. We are looking at the Q2 week schedule and the weekly schedule and we'll share the data that we have at ASH, and then we'll be in a position to discuss next step.
Operator
We will now take our next question is from Andy Hsieh of William Blair. Please go ahead.
Q – Andy Hsieh
Thanks for taking my question. And -- I guess the first question is for Dave.
Since you guys are talking about commercial preparation, maybe provide us with a framework in terms of what you're doing and in the event of a positive readout in the first half of next year, what is the commercial ramp going to look like?
Mark Enyedy
Yes. Maybe I can tackle that, Andy.
This is Mark from an operational perspective, and then Dave can talk about the spending part of it. So, right now we're focused on a couple of key activities.
The first of which is ensuring that we can secure a drug supply and so we have completed the drug substance runs. The drug product runs are nearing completion.
We'll put that drug upon stability and that will position us well for a second half 2019 BLA filing. So, we have the requisite data there.
In addition to that, operationally, we're gearing up for -- coming to the final event. And so, the process-wise, we've got operational metrics that are out to the sites in terms of data collection, cleaning and validation and all of that is on track.
And then finally, it's around the commercial planning. Right now, it's looking at go-to-market models, it's looking at physician targets and segmentation and matching that back against our go-to-market model, all with a view that with the benefit of a positive readout in the first half of 2019 we would hire in a Chief Commercial Officer and then begin recruiting our sales management and then that would be followed by the sales force in some period of time pre-launch, so that we're ready to go when we've got an approval.
So operationally, right now we're not -- we're not adding heads, but we are engaged with outside support around some of these key commercial questions and then talk to -- ask Dave to kind of comment on what that would look like from an expense perspective.
Dave Johnston
Thanks, Mark. Yes, as Mark highlighted, there is some activity going on right now, pre Phase 3 readout it's -- in terms of the financial scale relatively modest.
I think that our plan is to -- once we have positive Phase 3 readout, that's when we would really start to see the ramp up of both activities. And then along with that, you will see an increase in spending.
Now, it's important to understand that in the cash runway projection that we provided that's already been contemplated for the second half of 2019. So, it wouldn't be incremental to what we've already said.
So, in terms of the quarter-on-quarter spend, you'll see it -- I think fairly consistent with next couple of quarters and then in the second half of 2019, you'll see a ramp up toward our commercialization launch.
Andy Hsieh
Maybe the second question is for Anna. In the 779 abstract that was released yesterday, there were some adverse events.
I'm just wondering if these are treating related or basically just very common baseline patient characteristics in AML, in particular, I'm looking at 22% bacteremia and in pneumonia 20%.
Anna Berkenblit
Yes. So, Andy, these are patients with relapsed/refractory AML who've been through some very tough chemotherapy regimens and their immune system is quite compromised because of their underlying AML and -- AML patients, the way they die is they die of infection or bleeding because they don't have an immune system and they don't have platelets.
So, this is actually quite common in AML patients. And in dose escalation Phase 1, first, in human trial in relapsed/refractory AML, there is pretty well known underlying rate of adverse events that are disease-related and not drug-related.
And so, one of the things that we have done to make sure we are protecting patient safety and assessing the profile of our drug is to choose our centers quite wisely. So, investigators that we're working with, on both of our AML compounds are experienced AML investigators, who take care of a lot of AML patients on trial and off trial and they're really best positioned to work with us to help us understand when we are seeing adverse events if they are drug related or disease related.
And at this point, as we had said in the abstract, no dose limiting toxicities had been observed on either schedule for 779 thus far.
Operator
We will now take our next question from Kennen MacKay of RBC Capital Markets. Please go ahead.
Kennen MacKay
Thanks for taking the question and congrats on the execution, maybe for David just quick complement. I think that was one of the most concise, but still comprehensive financial reporting if I've ever heard on an earnings call.
[Multiple speakers] A real follow-up for Anna here, revisiting some of the data that we thought ASCO and ASMO from FORWARD II respective mirve plus, Avastin and mirve plus pembro cohort, it's sort of hard to definitively say that there is additive or synergistic benefit at least on the overall response rate level in FR alpha positive patients. On the call and at these events you brought up durability really being a focus here for additive synergistic unit.
Wondering if you could maybe elaborate a little bit on as to any rationale for why sort of anti-tumor benefit would be seen on duration versus magnitude of tumor shrinkage. And then if there are any sort of IO combination correlates out there or biomarkers, we should be looking to or even sort of biologic rationale that supports this type of synergistic duration benefit, but not necessarily in terms of magnitude of tumor cells.
Anna Berkenblit
Okay. So let me answer your question for each combination separately because the biology, I think is quite different.
Let me start with Avastin. So we already knew that with standard single-agent chemotherapy, you get a pretty modest response rate -- 10% to 20%.
And then if you add Avastin into it, you increase the response rate you increase duration of response and progression-free survival. So Avastin really helps when you're combining with pretty mediocre chemotherapy.
With mirvetuximab, we're already starting at baseline without a much higher response rate and so I think from an immediate anti-tumor shrinkage perspective, we're already focused on the medium to high patients who seem to have the deeper tumor shrinkage. And then I think Avastin maybe adding durability to that in terms of the integrity of the vasculature allowing for deeper tumor penetration into the tumor.
So I think that may be underlying the mechanism that we're seeing for enhanced benefit. So I think we're pleased with the data that we've seen combining mirvetuximab with Avastin, both from an efficacy perspective and also a tolerability perspective.
Because with mirvetuximab patients don't lose their hair and the neuropathy appears to be not as profound as with paclitaxel. So let me pivot now to the checkpoint inhibitor combination.
So I think what we've seen across tumor types with checkpoint inhibitors is that there is a tail. There is a tail on the curve and I think lung cancer is probably the best tumor type for us to learn from.
So when checkpoint inhibitors are given as monotherapy or in combination with chemotherapy in a variety of lung cancer settings. There is always a tail and it's really frustrating for lung cancer physicians when they start treating a patient because they can't yet predict which patients are going to have that durable benefit from the addition of a checkpoint inhibitor.
So I think the same can be said for ovarian cancer, where checkpoint inhibitors are just beginning to be utilized in clinical trials, and I would argue, have not achieved proof of concept yet. So I think we're watching the field closely.
So that if a biomarker does emerge for patient selection that really is robust enough, we'll be in a position to incorporate that, PDL-1 a selection is sort of helpful, but it's a pretty complicated field and I don't think that's the be all end all answer. So, all I can say is we've incorporated tumor biopsies in our Keytruda combination.
So that -- hopefully we will be able to interrogate the tumors. If it turns out that there is a marker, that's helpful.
We're just not aware of one right now that's really going to identify those patients who are going to be those with the most durable benefit.
Kennen MacKay
That's it. Thanks Anna.
Appreciate the explanation there, and looking forward to seeing some of the additional tumor biopsy test.
Operator
We will now take our next question from Jessica Fye of JPMorgan. Please go ahead.
Unknown Analyst
Hi, this is Yuka on the call for Jessica. Thank you for taking our questions.
Just one question for you. Following initial forward to Keytruda, mirvetuximab combo data ASMO, what do you think investors can or cannot read into data for FORWARD I?
Anna Berkenblit
So, investors can read into the data from the mirvetuximab plus Keytruda combination, that mirvetuximab is an active monotherapy and heavily pretreated ovarian cancer. And it is entirely consistent with what we have demonstrated in the initial first in human study across three separate ovarian cancer cohorts.
So that's what we can say now. The Phase 3 population in FORWARD I is restricted to platinum-resistant disease with one to three prior lines of therapy.
As a reminder, the mirvetuximab plus Keytruda expansion cohort excluded patients with one prior and focused on two to four prior lines of therapy. In the data set that we presented 37% of the patients had four or greater lines of therapy.
So they wouldn't even be included in our Phase III trial and we know that with additional lines of therapy benefit from any enough next subsequent therapy is less and less. So in summary, the data from our mirvetuximab plus Keytruda confirm the activity of mirvetuximab and it's just too soon to tell whether not pembrolizumab is adding anything.
Operator
Thank you. We will now take our next question from Boris Peaker of Cowen.
Please go ahead.
Boris Peaker
Great, thanks for squeezing me in. For a planning the pivotal combo study, I'm just curious, do you have to wait until this new Avastin combo reads out or would you have enough data from the combo studies you have ongoing right now?
Anna Berkenblit
So for us, when you say the pivotal combo study, are you referring to Keytruda or Avastin or the triplet or just …
Boris Peaker
Whichever you decide to do?
Anna Berkenblit
Okay, all right. So we need more durable data from the Keytruda combination to see whether or not there is a path for accelerated approval in heavily pretreated BRCA wild-type patients, number one.
Number two, we need additional data from our mirvetuximab plus Avastin that -- if it confirms the initial data that we've already generated that could support a registration trial then for platinum-resistant disease or again sort of platinum agnostic disease in previously treated patients for that doublet. But the other piece of data that we will have in 2019 is triplet data from Carboplatin plus mirvetuximab plus Avastin.
And so, we won't be able to start three pivotal trials all at once, but we're going to have the data that we need from these different combinations to help us prioritize them and figure out which will be the next registration trial we proceed with.
Boris Peaker
And lastly on 632, how many BPDCN patients you think we'll see at ASH?
Anna Berkenblit
The trial is open to AML and BPDCN. And we are enrolling AML and BPDCN patients and we look forward to sharing the data at ASH.
Boris Peaker
Okay. We'll see you at ASH.
Thank you.
Operator
We will now take our next question from Joseph Catanzaro of Piper Jaffray. Please go ahead.
Joseph Catanzaro
Hey guys. Thanks for squeezing me in.
Just one quick one from me. I was hoping if you could remind us whether there is any difference in the IGN payloads between 779 and 632 and then along those lines, is there anything in your 779 experience that will allow you to sort of move a bit quicker in dose escalation in reaching MTD for 632.
Thanks.
Richard Gregory
This is Rich Gregory. I'll take the first question and I'll let Anna handle the second one.
So in terms of the payloads mechanism of action they're entirely the same. They're both drugs that bind in the [DNA minor groove] and then chemically modified one strength of the DNA are alkylated.
However, the payload in 632 is about ten-fold more potent, the result of several years more structure related design and we've optimized the payload in terms of its potency in its bystander effect such that it is in our view a next generation or superior payload.
Anna Berkenblit
And then to the question of learnings applied from 779 to 632 to allow us to go faster, that's exactly right. So 779 was the first ADC with this novel class of payloads to enter human testing.
So we were very conservative in our selection of starting dose and in the dose escalation schedule in terms of the increments, based on the very nice safety profile that we see with 779 that enabled us to start at a relatively higher dose. Again, you have to account for the fact that 632 is more potent but, conceptually a relatively higher starting dose for 632 and also on more aggressive dose escalation schema.
So for example from dose level 1 to dose level 2, we actually were able to do a tripling of the dose for 632. So yes, it should enable us to move faster with 632 than with 779.
We're applying all the lessons learned.
Mark Enyedy
Great. I think that's the end of the question.
So I want to thank everybody for their time today and we will look forward to seeing you all at ASH.
Operator
Thank you, this concludes today's call. You may now disconnect.