U.S. Markets closed

Immunogen Inc (IMGN) Q1 2019 Earnings Call Transcript

Motley Fool Transcribers, The Motley Fool
Logo of jester cap with thought bubble.

Image source: The Motley Fool.

Immunogen Inc  (NASDAQ: IMGN)
Q1 2019 Earnings Call
May. 03, 2019, 8:00 a.m. ET

Contents:

  • Prepared Remarks
  • Questions and Answers
  • Call Participants

Prepared Remarks:

Operator

Good day, everyone, and welcome to the First Quarter 2019 Conference Call. Today's conference is being recorded. At this time, I would like to turn the conference over to Sarah Kiely, Director of Investor Relations and Corporate Communications. Please go ahead.

Sarah Kiely -- Director of 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 2019 financial results. This press release and a recording of the call can be found under the Investors & Media section of our website at immunogen.com.

On the call today are Mark Enyedy, our President and CEO; and Anna Berkenblit, our Chief Medical Officer. Rich Gregory, our Chief Scientific Officer; and Dave Foster, our Chief Accounting Officer, will join the team for the Q&A session.

During today's call, we will discuss recent progress, review our first quarter financial results and highlight 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 turn the call over to Mark.

Mark Enyedy -- President and Chief Executive Officer

Thanks, Sarah. Good morning, everyone, and thank you for joining us today.

In early March, we announced top line results from the Phase III FORWARD I study of mirvetuximab in platinum-resistant ovarian cancer patients. While we were disappointed that the trial did not meet its primary endpoint, we were encouraged to see a consistent efficacy signal in the pre-specified subset of patients with high folate receptor alpha expression.

Specifically, in comparison to chemotherapy, we observed more than twice the response rate and more durable responses with mirvetuximab in this patient population. In addition, progression free and overall survival were longer in the mirvetuximab treated patients. We believe this consistent efficacy, signal coupled with differentiated safety and tolerability, demonstrate a favorable benefit risk profile for mirvetuximab.

With the benefit of these additional analysis of the data from FORWARD I and input from our clinical and regulatory advisors, we will be meeting with the FDA this quarter to discuss the potential path to registration for mirvetuximab monotherapy in the FR alpha high population. We look forward to updating you on the outcome of those discussions.

Moving to our FORWARD II trial. We have generated promising data with mirvetuximab combination regimens with the goal of expanding our market opportunity from mirvetuximab into earlier lines of therapy. And we'll update you on our progress and upcoming data from this study. In addition, we are evaluating combination approaches as an independent avenue to support a label for mirvetuximab.

Looking beyond mirvetuximab, we are advancing our novel IGN programs, IMGN632 and IMGN779 in hematological malignancies. We continue to enroll patients in expansion cohorts for the Phase I study of IMGN632 in patients with relapsed or refractory AML and BPDCN, and we are nearing completion of accrual for our Phase I study of IMGN779 in AML patients, with data expected from both studies later this year. Separately, we are on track with IND enabling activities for IMGC936, our novel ADAM9-targeting ADC that's being developed in collaboration with MacroGenics with a submission plan for 936 before the end of this year.

Turning to our financial results, which were detailed in the press release we issued this morning. ImmunoGen is in a strong financial position, with approximately $270 million on the balance sheet, providing flexibility for continued investment in our portfolio. The previously announced operational review of the business to extend our cash runway is ongoing and we expect to announce the results of this effort following our engagement with FDA.

Regarding our first quarter financials, we generated $8.6 million in revenue, which included $8.5 million in non-cash royalty revenues related to Kadcyla sales. Our operating expenses for the first quarter were approximately $50 million compared with $57 million for the same quarter in 2018. The decrease was primarily related to lower clinical trial costs in the current period compared to the prior year, when these expenses were driven by accelerating patient accrual in FORWARD I.

As previously noted, we ended the quarter with approximately $270 million in cash and cash equivalents on the balance sheet. We will provide an update on our 2019 financial guidance following the completion of our operational review.

With that, I'll turn the call over to Anna to review our pipeline progress in more detail. Anna?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Thanks, Mark.

As mentioned, we recently announced top line results from the Phase III FORWARD I study of mirvetuximab soravtansine. While we are disappointed that the study did not meet its primary endpoint, we remain encouraged by the consistent signals of efficacy in the pre-specified high folate receptor alpha subset. Additional analyses we subsequently conducted reinforce the consistency of the efficacy signals we initially observed in the top line results.

From a safety perspective, mirvetuximab is well tolerated with fewer grade 3 or greater adverse events, dose modifications and treatment related discontinuations than chemotherapy. For those patients with high folate receptor alpha expression, we believe these data demonstrate a favorable benefit risk profile in platinum-resistant ovarian cancer, a population that still has a high unmet need, highlighted by recent disappointments from Phase III trials of a checkpoint inhibitor and a novel chemotherapy.

We have shared the FORWARD I data with mirvetuximab-experienced investigators and with additional clinical and regulatory advisors. We continue to hear that physicians want to be able to give mirvetuximab to their folate receptor alpha high ovarian cancer patients with platinum resistant disease who need more effective and well tolerated treatment options.

In other tumor types such as colon cancer and multiple myeloma, we know that patients live longer with the availability of additional effective lines of therapy. Within this context, we look forward to discussing with regulators a path forward for approval of mirvetuximab as a monotherapy. We are planning to submit the data to ESMO and present the data later this year.

Turning now to combinations. The tolerability profile of mirvetuximab, particularly the lack of myelosuppression, lends itself to combinations, which we are advancing in the FORWARD II trial. Our goal remains to establish mirvetuximab as the combination agent of choice in ovarian cancer, supporting use in earlier lines of therapy. In FORWARD II, we are looking at mirvetuximab doublets as well as a triplet combination cohort that is evaluating mirvetuximab plus carboplatin and Avastin in patients with recurrent platinum-sensitive disease. We will present mature data from the Avastin doublet cohort in platinum-resistant ovarian cancer at ASCO. Also at ASCO, Dr. Kristina (ph) will be presenting initial data from her mirvetuximab plus gemcitabine combination trial through the NCCN.

For the ongoing triplet cohort, we are planning to submit initial safety and efficacy data to ESMO. And as Mark noted, we continue to enroll patients in the second FORWARD II Avastin cohort, which evaluates mirvetuximab in platinum agnostic ovarian cancer. This platinum agnostic population includes the growing number of patients who progress after PARP inhibitor maintenance therapy.

Moving to our earlier stage portfolio, our novel IGNs IMGN632 and IMGN779. These are being evaluated for the treatment of hematologic malignancies with a focus on AML and BPDCN. As a reminder, IMGN632 is a CD123-targeting ADC that deploys our most potent IGN payload, while IMGN779 is our CD33 targeting ADC. Patient enrollment continues in our expansion cohorts of the Phase I study of 632 in patients with relapsed or refractory AML and BPDCN, with additional sites being opened in Europe, as well as in the Phase I study of 779 in AML.

We were also pleased to present encouraging preclinical activity in models of non small cell lung gastric and colorectal cancers for our newest candidate, IMGC936 at the AACR Annual Meeting. In total, we presented 11 posters at AACR, showcasing our most recent ADC advancements and further demonstrating continued innovation from our research platform. As Mark noted, we expect to file an IND for IMGC936 before the end of the year. Looking ahead, we plan to present updated IMGN632 data with additional AML and BPDCN patients and establish the recommended Phase II doses scheduled this year. We will initiate combination studies with 632 and establish the recommended Phase II dose for IMGN779.

With that, I'll turn the call back over to Mark.

Mark Enyedy -- President and Chief Executive Officer

Thanks, Anna.

As we move forward in 2019, we remain focused on executing our near-term priorities, which include, first, working with the FDA and EMA to determine a potential avenue to approval for mirvetuximab as monotherapy in platinum resistant ovarian cancer; generating additional combination data to support market expansion and as an independent path to a label in ovarian cancer; continuing to advance our portfolio of next generation ADCs; and finally, completing a review of our operations with the goal of extending our cash position.

I want to remind everyone that while we have disclosed top line results from FORWARD I, we are not in a position to discuss full details of the study today in order to preserve the opportunity to present the data in a future medical meeting.

With that, we'll open the line for questions.

Questions and Answers:

Operator

Thank you. (Operator Instructions) Our first question today comes from John Newman from Canaccord.

John Newman -- Canaccord -- Analyst

Hey guys, good morning. Thanks very much for taking my question. Well, Mark and Anna, just curious in terms of the interactions that you plan to have with the European regulators. I just wonder if you would expect that the approach and considerations there will be similar to the FDA or -- just wondered if perhaps there would be any differences in the way that they might think about things going forward. Thanks.

Mark Enyedy -- President and Chief Executive Officer

Yeah. So those agencies have somewhat different approaches to assessing circumstances like we find ourselves in. And so the FDA has a very clear avenue related to, in our case, Subpart E approvals for biologics for considering -- for accelerated approvals based on surrogate endpoints. And while there is a similar provision called conditional marketing authorization for the EMA, the approach to the agencies differs to some degree. And so the implications for us, as it relates to that, is one of timing. And so we are engaging with Europe, but the timeline there will be longer than our engagement with FDA. Beyond that, they also tend to look at the data differently and surrogate endpoints can differ. The approach to even full approval can differ. So for example, FDA is perfectly happy with progression free survival as an endpoint for full approval, in Europe, beyond PFS, they often look for patient reported outcomes, for example, to support a PFS finding. And so, while, as I said, the general approach, the broad framework, are analogous, the details do become important.

John Newman -- Canaccord -- Analyst

Okay. Great. Thanks. And then maybe just one question for Anna. Obviously, I know that you can't discuss details on the data at this time. But just wondered if you could give us a sense, just broadly speaking, where the survival events sort of fell out in the initial report. Just curious if you would say that there were a meaningful number of survival events at that time. Obviously, we will get the full data at a later time point. Thanks.

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Right. So, as a reminder, overall survival in platinum resistant ovarian cancer is somewhere between 11 and 14 months. That really highlights the dire situation that these patients are in. You may recall that we completed enrollment in the trial last year in the March-April timeframe, and the data cut that we used for the primary analysis was in January of this year, so approximately nine months in between. So you can imagine, especially with the very brisk enrollment toward the end, that there are many patients who have not yet really had the opportunity to potentially live past that median endpoint, if you will, the median time for overall survival. That being said, we enrolled patients over a 15 month period, and so -- what I would say is the hazard ratio that we reported in the press release, with a hazard ratio of 0.62 and a p-value of 0.033, was based on a reasonable number of events. However, the data were immature, and we continue to follow patients for overall survival, which is a key secondary endpoint.

John Newman -- Canaccord -- Analyst

Great. Thanks very much, guys.

Operator

Moving on, our next question comes from Andy Hsieh from William Blair.

Andy Hsieh -- William Blair -- Analyst

Thanks for taking my questions. I'm just wondering from a timing of various scenario perspective, I'm just wondering if you can kind of lay out, let's say, in the event of a positive FDA meeting, when, how long would it take for the application to go in. I realize that you have fast track designation, so that means you can kind of start parts of that and get the ball start rolling. And in the negative event, how soon can you start the second Phase III study?

Mark Enyedy -- President and Chief Executive Officer

Yeah. So, in the event of a positive FDA meeting, we would expect to be able to file the BLA before the end of the year. In terms of initiating a confirmatory study, some of that's going to depend on the dialogue that we have with the agency and what their perspective is vis-a-vis both the initial application and then what their requirements are for full approval. And so it's a little bit hard to time that, Andy, at this point. I think that should await the outcome of the discussion that we have with them.

Andy Hsieh -- William Blair -- Analyst

Okay. Yeah, that was fair enough. I understand. And I guess based on your discussions with various experts -- regulatory experts, clinical experts, maybe on a high level, what are some aspects these experts like and what are some aspects that cause maybe some hesitation in terms of recommending going forward? Just curious if we can kind of talk, at a very high level, about those.

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Sure. The outside consultants that we have engaged with, Andy, include clinical drug development experts and regulatory experts. And I'll start with the things that we consistently hear are that they are impressed with the consistency of the efficacy signals that we see in the high subset, the high FR alpha subset, coupled with the favorable tolerability and differentiated safety profile. So when you package those together, there is a favorable benefit/risk we believe in this high FR alpha subset. As a reminder, we went head to head against active chemotherapy that physicians know how to use. And even with that, we had fewer discontinuations due to drug related adverse events. And also as a reminder, we didn't get this efficacy signal based on adding to another agent so that there is a toxicity price to pay. So really from a benefit/risk perspective, it's clear that the high subgroup does have a favorable benefit/risk. Where the conversation then goes, though, is how to interpret the data from the Phase III trial, given that we did not meet the primary endpoint. And so, given, the context in which we generated these data in platinum resistant patients who need more effective and well tolerated therapies, we are looking forward to discuss the data with the regulators to discuss a path forward.

Andy Hsieh -- William Blair -- Analyst

I see. Okay. That's super helpful. Thank you very much for taking my questions.

Operator

Moving on, we'll hear from Kennan MacKay from RBC Capital Markets.

Kennan MacKay -- RBC Capital Markets -- Analyst

Hi, this is Kennan. Thanks for taking the question. Anna, can you help us maybe understand the additional efficacy analyses that you've mentioned? Are these things like time to second progression? Or what should we be thinking about here? You'd mentioned those were encouraging. And then secondly, it's very clear that you're taking an approach in the EMA aiming for conditional approval. To be clear, in the US, are you taking the same approach with the FDA, aiming for accelerated approval or is full approval potentially on the table? And is this something that has to be sort of declared ahead at the end of Phase III meeting when you discuss a path forward to sort of set the agenda for the meeting? Thanks.

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Yeah. So, in terms of the additional efficacy analyses, Kennan, the top line data that we reported March 1st were really the key efficacy analyses that were pre-specified in the statistical analysis plan. However, there were many other efficacy analyses that were pre-specified in the statistical analysis plan, and so we have now gotten those data as well. Specifically around PFS 2 or progression free survival 2, which is similar to what you were describing, we were also looking at CA 125 responses, also looking at patient reported outcome data, also looking at pre-specified subgroup analyses within the ITT and the high FR alpha subset, so looking at one to two versus three priors, looking at additional patient subsets. And, again, the data are consistent. So, this is why we believe that the data initially presented with the top line data are really indicative of a consistent efficacy signal in the high FR alpha subgroup. Turning to your question around accelerated approval and conditional marketing authorization, we believe that both of those are the reasonable path forward for discussion with the regulators in the US and Europe, respectively.

Kennan MacKay -- RBC Capital Markets -- Analyst

Thanks for answering the questions.

Operator

Our next question is from Michael Schmidt from Guggenheim.

Michael Schmidt -- Guggenheim -- Analyst

Hey guys, good morning. Thanks for taking my questions. Maybe just a follow-up on the -- just a comment just now on the additional analyses. It was interesting the comments you made around OS, and I was just wondering if you would be doing another OS data analysis before heading to the FDA and/or whether some of that will be included in the ESMO presentation. And then I had a follow-up as well.

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

So we are continuing to follow patients for overall survival, and they've been consented for that type of follow-up and we are doing that.

Michael Schmidt -- Guggenheim -- Analyst

So you will have more mature OS data for your FDA meetings?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

We will be providing a data package to FDA that will facilitate the most productive discussion regarding a potential path forward.

Michael Schmidt -- Guggenheim -- Analyst

Okay. Very helpful. Thanks. And then just looking at some of the other data presentations that are coming up, you mentioned ASCO and then potentially ESMO. Could you just give us some more details with respect to what expectations are for those updates in terms of patient numbers, for example, and interpretation of those data?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Sure. So at ASCO, we will present mature data from our initial mirvetuximab plus bevacizumab or Avastin cohort. You may recall that last year at ASCO, we presented data on 54 patients from a trial that was -- from the trial that was still enrolling. Now we have complete data from 66 patients. They all have platinum resistant disease, and so we will be presenting mature safety and efficacy data from that entire cohort. Turning to ESMO, we are in the midst of finalizing abstracts for submission, both for FORWARD I and for the triplet. The triplet is carboplatin plus mirvetuximab plus Avastin, and we completed enrollment in that cohort at the end of December last year. So this triplet -- at ESMO, if our abstract is accepted, this will be the first data for the triplet showing safety, and at this point we have mature enough response rate data that we'll be able to share that. But remember, these patients treated with triplet therapy do extremely well with a long progression free survival. And so we will not have mature data for any time to event endpoint such as PFS or even duration of response.

Michael Schmidt -- Guggenheim -- Analyst

Okay. Very helpful. Thank you.

Operator

And we'll go next to from Biren Amin from Jefferies.

Biren Amin -- Jefferies -- Analyst

Hi guys, thanks for taking my questions. Just on this FDA meeting, Mark, when would you provide, I guess, an update from that meeting? Would it be after you receive the FDA minutes?

Mark Enyedy -- President and Chief Executive Officer

I think that would be the most prudent course. I think if the dialogue and the meeting is unequivocal and unambiguous, then that would provide an opportunity for us to communicate. I think to the extent that there are more complex, nuanced conversations that would probably benefit from minuting, then we might wait to have the benefit of the written communication from the agency.

Biren Amin -- Jefferies -- Analyst

Got it. And then I think through the course of this conference call, you've communicated that your external advisors view the data as consistent. But would they view the data as clinically relevant as it relates to PFS and OS in the FR high patients?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Yes. The reason I say that, Biren is, in platinum resistant ovarian cancer, the median overall survival is somewhere between 11 and 14 months, and really no monotherapy has ever demonstrated an overall survival benefit in this patient population with such high unmet need. We do continue to follow our patients for overall survival. And while that is important and I would argue that's the gold standard, other characteristics are equally as important, including progression free survival, response rate and patient reported outcomes. Ultimately, we want patients to feel better and live longer. And so far, all of the efficacy parameters that we've looked at suggest that in our minds, mirvetuximab will be an important addition to the armamentarium for these patients who have limited options with poor outcomes currently.

Biren Amin -- Jefferies -- Analyst

All right. And then I guess from our view, we haven't seen the full data, and I guess we won't until ESMO. So I guess with the FDA meeting and -- where you provide the full data, would you characterize if there is any baseline imbalances in the FR high patients across the arms?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Given the analyses that we've looked at in the ITT population and a pre-specified high FR alpha subset, we do not see any glaring imbalances that could confound interpretation of the data.

Biren Amin -- Jefferies -- Analyst

Great. Thank you.

Operator

Our next question comes from Jonathan Chang from SVB Leerink.

David Ruch -- SVB Leerink -- Analyst

Hi guys, this is David on for Jonathan. Thanks for taking my questions. Just wanted to get kind of a general opinion on this without going too deep into the data. But now that you've had a chance to look at the FORWARD I data a little bit further, how are you thinking about folate receptor alpha as a prognostic factor? And can you give any guidance on how your thinking has changed on that?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

So, there are some retrospective data in the literature suggesting that folate receptor alpha is a poor prognostic factor, and we remain interested in assessing that. I would say that the data from our Phase III trial are quite important in that regard. As a reminder, we enrolled patients with medium and high FR alpha expression. We did not enroll patients with lower or negative FR alpha expression, and so I think our dataset will be important to help folks start to understand FR alpha as a prognostic factor. But I'd say there's more work to be done there. The important point, though, is that FR alpha is a predictive factor for benefit from mirvetuximab.

David Ruch -- SVB Leerink -- Analyst

Great. And just wanted to ask, again, if you could give any potential path forward following discussions with regulators? If you could just tell us a little bit about how you're thinking about the folate-receptor alpha high group and kind of what that looks like?

Mark Enyedy -- President and Chief Executive Officer

So, I think the question is, if the FDA is receptive to this data package, then our expectation would be to file a BLA before the end of this year. If they're receptive, given the unmet need here, I think we could reasonably expect, under the circumstances, to obtain priority review for that application. And so the approval would follow in a six to eight month time frame after the filing. So does that answer your question?

David Ruch -- SVB Leerink -- Analyst

Yeah. That's helpful. And then just one more from me. Now, if you could just clarify for the combination studies, both the Avastin combo and the triplet, do those have the same mitigation strategies for adverse events as the monotherapy, for example, the eye drops?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Yes. Yes, they do. And I should also mention, we do have an ongoing second mirvetuximab plus Avastin cohort that is currently enrolling as well. And I should also mention that after FORWARD I closed end we announced the data, enrollment in that combination has actually picked up a bit.

David Ruch -- SVB Leerink -- Analyst

Great. Thanks so much, and I appreciate the follow-up.

Operator

Boris Peaker from Cowen has our next question.

Boris Peaker -- Cowen -- Analyst

Great. Thanks. So, just probing further on the FORWARD I dataset. I mean, we've talked a lot about the folate-receptor high patients. You haven't disclosed obviously a lot of data on the folate receptor, the medium expressers, but my calculations suggest that they had a positive hazard ratio. Can you comment on that? Why was there a positive hazard ratio for that subgroup? What could have caused that relative to the control used by physicians?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

So, as a reminder, when we designed the trial, we did so with a relative paucity of data. But all of the data that we had suggested two things: one, the higher the folate receptor alpha expression, the deeper and more durable the tumor shrinkage; and two, the mediums, they looked like they were benefiting at least as well as chemotherapy, and we felt that from the safety profile of mirvetuximab, there could be a real advantage in terms of no hair loss, less neuropathy and less myelosuppression. So we felt, again, when we designed the study, that it was likely that the mediums would do at least as well as the chemotherapy. As you note from your calculations, Boris, the efficacy really seems to be in the high FR alpha subgroup, and so we have a path forward to select the patients who are most likely to benefit from mirvetuximab and exclude those who might not. And we do look forward to submitting, to presenting the full dataset so everyone can see the data for themselves at a major medical meeting.

Boris Peaker -- Cowen -- Analyst

Gotcha. Can you think of any kind of an example? I'm just curious if you've done an analysis where the FDA has accepted a subgroup of a study as a basis for approval when there is a clear strong efficacy signal from that subgroup.

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

So what distinguishes our study is that this was a pre-specified subgroup. This was not a post hoc analysis. However, the study did not meet the primary endpoint based on how we designed it, and this is why we look forward to engaging FDA with a path forward for approval.

Boris Peaker -- Cowen -- Analyst

Okay. And just lastly on 632. I'm just curious if you could comment on how many relapsed refractory AML patients and separately how many BPDCN patients have you enrolled to date.

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

I can't comment on the exact number. But since ASH, we have continued to enroll both AML and BPDCN patients, and we look forward to sharing data at ASH at the end of this year if our abstract is accepted after we submit it.

Boris Peaker -- Cowen -- Analyst

Great. Thank you very much for taking my questions.

Operator

(Operator Instructions) Our next question comes from Jessica Fye from JPMorgan.

Jessica Fye -- JPMorgan -- Analyst

Great. Good morning, guys. Thanks for taking my questions. Just following up on the last question, I thought it was interesting. Is there a precedent you can think of where there was a pre-specified subgroup that represented the basis for approval? And then on 632, can you help us think more specifically about when you might be able to select the go-forward dose? Trying to understand if that's something that we could hear, say, prior to ASH to the extent that's moving along nicely or if we should just expect to kind of hear that update when we see the next data update.

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Yeah. So regarding regulatory precedents, I do believe there was one for pemetrexed, where they were able to get approval in a pre-specified subset despite a negative outcome. I'm not able to share the details, but I would point you in that direction as a regulatory precedent. Regarding 632, could you repeat the question? Sorry.

Jessica Fye -- JPMorgan -- Analyst

Yeah. It was just the potential for us to hear about selection of the go-forward dose kind of as a data point for progress prior to actually seeing the next data update, which -- best guess would be like December.

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

I don't think we can commit to a timeline, but we are planning to start combination work with 632 this year.

Jessica Fye -- JPMorgan -- Analyst

Okay. Thank you.

Operator

Our next question comes from Debjit Chattopadhyay from H.C. Wainwright.

Debjit Chattopadhyay -- H.C. Wainwright -- Analyst

Hey, good morning. So was the PRO collected in all patients prospectively? The reason I ask is, because Mark had mentioned you need to -- at least historically in the EMA, combination of a PRO plus PFS would be acceptable.

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Yes, Debjit. We had a pre-specified key secondary endpoint that was based on PRO. We used the same tool and subscale that was used in the AURELIA study. There is a JCO article from 2014 by (inaudible) where they present the PRO data from the AURELIA study, showing that when you add bevacizumab to chemotherapy and compare it with chemotherapy, there is an improvement of greater than 15% in -- sorry, greater than 15 points in the six-question subset of abdominal and GI symptoms, so in other words, the six key questions that are really focused on symptoms from cancer, patients who got bevacizumab and chemo did better, they felt better than chemotherapy. So we applied the same PRO analysis to our dataset, and we look forward to sharing those data at a future medical meeting.

Debjit Chattopadhyay -- H.C. Wainwright -- Analyst

So, Anna, just to clarify. The enrollment criteria, how closely, from an exclusion perspective, patients at risk for abdominal bleeding events -- was that, similar to the AURELIA, from an exclusion perspective?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Our trial looked at monotherapy mirvetuximab versus monotherapy chemotherapy. So the exclusion criteria for Avastin were not really relevant for our trial, Debjit. So patients who are at risk for abdominal perforation or bleeding based on their tumor really should not get on Avastin containing regimen. So for our trial, we had no specifications around that. And in fact, we -- Avastin is approved with chemotherapy in one to two priors, but as you point out, it's not appropriate for everyone, so patients do need more options.

Debjit Chattopadhyay -- H.C. Wainwright -- Analyst

Great. And then from your discussions with your investigators, how are the defining clinically relevant benefit? Is it greater than two months or one and a half to two months is plenty in this indication, especially if it -- there is a trend toward increased overall survival, even though it may not be stat safe (ph) given that the study was not followed forward?

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

Yeah. So, our view is that it's the totality of the data, exactly, where it's PFS, overall response rate, overall survival, who is really benefiting, how long are they benefiting, how do they feel, and what price are they paying from a side effect perspective, right?

Debjit Chattopadhyay -- H.C. Wainwright -- Analyst

So just one last follow-up. So in case -- just playing a devil's advocate, in case there is a pushback on the BLA filing, would you consider proceeding with another single agent study? Or would you pivot to a combination with Avastin or the triplet given that you're seeing uniform benefits in one to two versus three, as you mentioned in your prepared remarks and during the questions? Thank you so much.

Mark Enyedy -- President and Chief Executive Officer

Yeah, I think it's going to depend on what the regulators have to say about the existing dataset. We were able, in this study, to identify a pre-specified subset of patients with FR alpha high, and if the FDA don't think those data -- the totality of those data are compelling, then I think that drives us down one path. If, on the other hand, their view is, it looks good but we want to see more patients, that gives us a different set of considerations. And so that's -- I think it will depend on what they have to say. What we can say at this point is we are moving forward with the combination studies. We're encouraged by those data, and we will continue that work.

Debjit Chattopadhyay -- H.C. Wainwright -- Analyst

Thank you so much, and good luck.

Mark Enyedy -- President and Chief Executive Officer

Thank you.

Operator

(Operator Instructions) And it appears there are no further questions at this time. Speakers, I'll turn the conference back to you.

Mark Enyedy -- President and Chief Executive Officer

Great, thank you. We very much appreciate your time and look forward to keeping you up-to-date on our progress, including the outcome of our regulatory discussions this quarter and to seeing you all at ASCO. Thanks.

Operator

And it does conclude our conference today. Thank you for your participation. You may now disconnect.

Duration: 41 minutes

Call participants:

Sarah Kiely -- Director of Investor Relations

Mark Enyedy -- President and Chief Executive Officer

Anna Berkenblit -- Senior Vice President & Chief Medical Officer

John Newman -- Canaccord -- Analyst

Andy Hsieh -- William Blair -- Analyst

Kennan MacKay -- RBC Capital Markets -- Analyst

Michael Schmidt -- Guggenheim -- Analyst

Biren Amin -- Jefferies -- Analyst

David Ruch -- SVB Leerink -- Analyst

Boris Peaker -- Cowen -- Analyst

Jessica Fye -- JPMorgan -- Analyst

Debjit Chattopadhyay -- H.C. Wainwright -- Analyst

More IMGN analysis

Transcript powered by AlphaStreet

This article is a transcript of this conference call produced for The Motley Fool. While we strive for our Foolish Best, there may be errors, omissions, or inaccuracies in this transcript. As with all our articles, The Motley Fool does not assume any responsibility for your use of this content, and we strongly encourage you to do your own research, including listening to the call yourself and reading the company's SEC filings. Please see our Terms and Conditions for additional details, including our Obligatory Capitalized Disclaimers of Liability.

More From The Motley Fool

Motley Fool Transcribers has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.