ImmunoGen Inc. (IMGN) Q4 2020 Earnings Call Transcript

ImmunoGen Inc. (NASDAQ: IMGN) Q4 2020 earnings call dated Feb. 12, 2021

Corporate 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

Susan Altschuller — Senior Vice President and Chief Financial Officer

Analysts:

John Newman — Canaccord Genuity — Analyst

Yige Guo — Guggenheim Securities — Analyst

Boris Peaker — Cowen and Company — Analyst

Andy T. Hsieh — William Blair & Company — Analyst

Kennen MacKay — RBC Capital Markets — Analyst

Luke Brennan — J.P. Morgan — Analyst

Biren Amin — Jefferies & Company — Analyst

Jonathan Chang — SVB Leerink — Analyst

Swayampakula Ramakanth — H.C. Wainwright & Co. — Analyst

Presentation:

Operator

Good morning and welcome to ImmunoGen’s Fourth Quarter and Full-Year 2020 Financial and Operating Results Conference Call. Today’s conference is being recorded.

At this time, I would like to turn the call over to Courtney O’Konek, Senior Director of Corporate Communications and Investor Relations. Please go ahead.

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 fourth quarter and full-year 2020 financial results. This press release and a recording 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; Anna Berkenblit, our Chief Medical Officer; and Susan Altschuller, our Chief Financial Officer.

During today’s call, we will review key accomplishments for the business over the last 12 months, our financial results and highlight upcoming anticipated events. During the discussion, we will use forward-looking statements and our actual results may differ materially from such statements. Descriptions of the risks and uncertainties associated with an investment in ImmunoGen are included in our SEC filings.

And with that, I’ll turn the call over to Mark.

Mark Enyedy — President and Chief Executive Officer

Thanks, Courtney, and good morning, everyone, and thank you for joining us today. Despite the challenges of the pandemic, 2020 was a transformative year for ImmunoGen, as we adjusted to new ways of working, advanced our portfolio, strengthened our management team and balance sheet and positioned the business for two potential product launches next year.

Just to expand on a few of these points beginning with our lead program, mirvetuximab, in ovarian cancer. As a reminder, our goals for this program are to obtain initial approval as monotherapy in patients with platinum-resistant disease in 2022 and to expand into earlier lines of therapy with an emphasis on combination regimens. We made significant progress towards each of these objectives over the last year. With our monotherapy program, we expect to deliver top line results in the third quarter and to submit the BLA by the end of this year to support accelerated approval in 2022. For our combination studies, we presented impressive data at both ASCO and ESMO last year, demonstrating that mirvetuximab has the potential to serve as the combination agent of choice in both platinum-sensitive and platinum-resistant ovarian cancer. Anna will cover these results in more detail later in the call. With the benefit of the data generated thus far, we believe there is a potential to obtain Compendia Listings for combination use of mirvetuximab in close proximity to our initial monotherapy approval.

Turning to our second pivotal program, IMGN632, which is our CD123-targeting ADC. We were pleased to receive Breakthrough Therapy designation in relapsed-refractory BPDCN in the fourth quarter and to align with FDA on a path to support potential full approval in patients with BPDCN. Updated data presented at ASH 2020 demonstrated the encouraging anti-tumor activity and favorable safety profile we’ve seen with 632 in the clinic and increase our confidence in its potential to become the best-in-class treatment option for patients with BPDCN.

In addition to our late-stage portfolio, our pipeline includes two additional innovative ADCs. In November, we enrolled the first patient in the Phase 1 dose escalation study of IMGC936, which we are co-developing with MacroGenics. 936 is a first-in-class ADC directed to ADAM9, which is a novel target expressed on a wide range of solid tumors. In tandem, we advanced our next-generation anti-FR alpha ADC, IMGN151, into preclinical development. 151 integrates innovation into each of the three components of the ADC, which should allow us to address patient populations with lower levels of FR alpha expression, including tumor types outside of ovarian cancer.

A key element of our strategy is partnering, where we made notable progress in 2020 with our agreement with Huadong Medicine to develop and commercialize mirvetuximab in Greater China. This collaboration is off to a strong start with Huadong recently receiving acceptance of an IND application for mirvetuximab in China from the NMPA.

Finally, through a combination of business development and activity under our ATM facility, we added more than $140 million to our balance sheet in the fourth quarter.

On the strength of our performance in 2020, we are excited about the year ahead with several important milestones. As I mentioned earlier in the call, for mirvetuximab, we expect to report top line data for SORAYA in the third quarter, followed by a submission by the end of the year. We also anticipate sharing final data from the FORWARD II doublet cohort evaluating mirvetuximab in combination with bevacizumab in recurrent ovarian cancer at ASCO in June.

For IMGN632, we expect to complete enrollment and share top line data for our pivotal frontline cohort in the Phase 1/2 BPDCN study in 12 to 18 months. We also plan to report data from our combination regimens evaluating IMGN632 with azacitidine and/or venetoclax in patients with relapsed-refractory and frontline AML at ASH.

For IMGC936, we will continue to enroll patients in the Phase 1 dose escalation study and anticipate initial data late this year or early next. And for IMGN151, we plan to submit the IND by year-end. So with a full calendar of important events, we look forward to a productive 2021.

With that, I’ll turn the call over to Anna to provide some additional color on our clinical programs. Anna?

Anna Berkenblit — Senior Vice President, Chief Medical Officer

Thanks, Mark. We have covered the ongoing progress and upcoming milestones for our mirvetuximab monotherapy program. So I’ll direct my comments this morning to our combination studies. Starting with the mirvetuximab plus bevacizumab combination, we presented initial efficacy and safety data of the doublets from our Phase 1b FORWARD II study in platinum agnostic, recurrent ovarian cancer in an oral session at ASCO 2020. We are particularly encouraged by the overall response rate of 64% observed in patients with high FR alpha expression regardless of platinum status, and look forward to the continued evaluation of mirvetuximab with bevacizumab in this growing population of recurrent ovarian cancer patients for whom a non-platinum-based regimen would be appropriate. As Mark mentioned, we plan to present mature data from this study at ASCO this year.

We also presented final data from our FORWARD II triplet cohort evaluating mirvetuximab in combination with carboplatin and bevacizumab at ESMO 2020. In this cohort of patients with medium or high levels of folate receptor alpha, we observed a confirmed overall response rate of 83% with a median duration of response of 10.9 months and the median progression-free survival of 12.8 months. These efficacy data are noteworthy as the population enrolled is more heavily pre-treated with a greater percent of patients having had more than one prior lines of therapy, as well as more prior targeted therapies, including bevacizumab and PARP inhibitors than in previously published triplet trials in recurrent platinum-sensitive ovarian cancer.

Going forward, we will be supporting two investigator-sponsored trials to generate additional data for the mirvetuximab plus carboplatin doublet this year. A randomized Phase 2 study of about 140 patients in recurrent platinum-sensitive ovarian cancer and 70 patient neo-adjuvant study. Having generated a wealth of data demonstrating encouraging efficacy and favorable tolerability, mirvetuximab continues to show promise in combination. In addition to the potential for Compendia Listings contemporaneous with mirvetuximab’s initial approval, we are working to define a formal path to label expansion for mirvetuximab.

Moving to IMGN632. Having received Breakthrough Designation and alignment on a path to full approval in BPDCN with FDA, we are enrolling up to 20 patients in the pivotal frontline cohort of the Phase 1/2 study of IMGN632 in BPDCN and expect to complete enrollment and generate top line data in 12 to 18 months. Notably, we have previously enrolled three patients who meet the frontline eligibility criteria and have observed clinical complete responses in all three of these patients. While we are unable to count these patients towards our prospective cohort of 20 patients, these data are encouraging.

At ASH, in December last year, we presented updated safety and efficacy findings from the Phase 1/2 study of IMGN632 in patients with relapsed-refractory BPDCN. These data demonstrated an overall response rate of 29% in all relapsed-refractory patients. This activity demonstrates the potential for IMGN632, particularly in patients who received prior intensive therapy, including those who received prior tagraxofusp-erzs. Importantly, IMGN632 has a favorable safety profile without capillary leak syndrome, drug-related discontinuations or drug-related death, and with a 0% 30-day mortality rate. Accordingly, it is well tolerated as a brief outpatient infusion once every three weeks without need for hospitalization for initial administration. Taken together, the safety, efficacy and convenience of IMGN632 to reinforce the potential of this CD123-targeting ADC as a best-in-class treatment option for BPDCN patients.

Also at ASH, our collaborators at MD Anderson Cancer Center presented preclinical data in relapsed-refractory AML that further support the combination of IMGN632 with azacitidine and venetoclax. In AML cell lines and patient-derived xenograft models, the triplet has demonstrated synergistic cell death with the potential to overcome resistance to VEN/AZA and superior anti-leukemia activity over both VEN/AZA as a doublet and IMGN632 monotherapy. These data further support the addition of a CD123-targeted ADC with a novel DNA damaging payload to standard of care in AML.

Our Phase 1b/2 802 study is designed to determine the safety, tolerability and preliminary anti-leukemia activity of IMGN632 when administered in combination with azacitidine and/or venetoclax to patients with relapsed and frontline CD123 positive AML. The study is in the dose escalation phase and enrolling relapsed and refractory patients to determine the recommended Phase 2 dose of IMGN632 in combination. We continue to observe encouraging initial anti-leukemia activity and a well-tolerated safety profile without dose limiting toxicity observed in the triplet. We look forward to the continued evaluation of the IMGN632 triplet and anticipate sharing data from this study at ASH once we have identified a recommended Phase 2 dose and schedule for the combination for further study. We also continue to evaluate IMGN632 as monotherapy in minimal residual disease positive AML.

With that, I’ll turn the call over to Susan to cover our financials. Susan?

Susan Altschuller — Senior Vice President and Chief Financial Officer

Thanks, Anna. Starting with our results for the full-year 2020. We generated $132.3 million in revenue, $68.5 million of which came from non-cash royalty revenues. The remainder coming from license and milestone fees, which include recognition of $60.5 million from the upfront fee previously received under the collaboration with Jazz.

Operating expenses were $154.7 million comprised of $114.6 million of R&D expenses, compared with $114.5 million in 2019.

G&A expenses were $38.6 million, compared to $38.5 million in 2019. In addition, we incurred a $1.5 million restructuring charge comprised substantially of retention costs.

We ended 2020 with $293.9 million in cash on the balance sheet. Subsequent to year-end, in January, we sold an additional 4.5 million shares of common stock through our ATM facility, generating additional gross proceeds of approximately $35 million.

Turning to our financial guidance for 2021. We expect revenues to be between $65 million and $75 million. Operating expenses between $200 million and $210 million and cash and cash equivalents at year-end to be between $140 million and $150 million. This provides us with sufficient runway to fund operations into the second half of 2022. I’ll point out that revenue guidance includes the assumption that a portion of the $40 million upfront license fee from Huadong Medicine will be recognized in 2021 as the upfront fee will be amortized over time as clinical supply requirements are delivered. In addition, ImmunoGen expects its non-cash royalty revenues to reduce starting in the second half of this year based on the terms of prior royalty transactions for Kadcyla.

With that, I will turn the call over to Mark for closing comments. Mark?

Mark Enyedy — President and Chief Executive Officer

Thanks, Susan. So, after a transformative 2020, we entered this year with significant momentum and strong prospects for the business. With an important near-term pivotal readout for our lead program, a second pivotal program with data in 12 months to 18 months, our earlier stage portfolio accelerating and a strong cash position to carry us past our first approval, we have the right strategy, team and resources in place to generate value in the near- and long-term as we transition to a fully integrated oncology company and bring our first two products to market in 2022.

With that, we’ll open the call for questions.

Questions and Answers:

 

Operator

Thank you. [Operator Instructions] And our first question comes from John Newman from Canaccord. Your line is open.

John Newman — Canaccord Genuity — Analyst

Hi, guys. Good morning. Thanks for taking my question. Just two quick questions here. The first one, for the FORWARD I study for mirvetuximab, I believe you had previously over-enrolled that study a bit. Obviously, I know that things are difficult and different in the COVID environment. But I’m just curious if to — whether you would be open to some additional patient enrollment for SORAYA if the demand is there. Thanks.

Anna Berkenblit — Senior Vice President, Chief Medical Officer

Thanks, John. So, we over-enrolled FORWARD I by about 10%, which is really the upper limit that’s considered acceptable when you’re thinking about study design. You want to enroll the patients to answer the question that you set out to answer. It turned out that was FORWARD I enrollment at the end was very brisk. And so, it worked out to patients’ benefit because there were patients who met all the eligibility criteria, had consented and thankfully, we were able to accommodate that 10% more than we had originally designed the study for. I wouldn’t be surprised if the same occurs with SORAYA and MIRASOL.

John Newman — Canaccord Genuity — Analyst

Great. Thank you. The second question I have, regarding Compendia Listing — potential Compendia Listing for mirvetuximab combination therapy. Just curious, how soon after mirvetuximab approval as a monotherapy might you be able to file for that Compendia Listing? Thanks.

Mark Enyedy — President and Chief Executive Officer

Yeah. Almost immediately, John. So, what’s required is two peer-reviewed publications. And so, the expectation is to get the results of — on the two cohorts that we run so far with mirvetuximab into journals and then use that as the basis for the submission. But the expectation is to move very quickly following the initial approval to work with the Compendia to have those studies included in their treatment guidelines.

John Newman — Canaccord Genuity — Analyst

Okay, great. Thank you very much.

Operator

Thank you. Our next question comes from Michael Schmidt from Guggenheim Securities. Your line is open.

Yige Guo — Guggenheim Securities — Analyst

Hi. Good morning. This is Yige on for Michael. Congrats on the progress. And thanks for taking our questions. Our first question is on mirvetuximab, maybe can you provide any color on the MIRV, Avastin combo mature data to be presented at ASCO? And since there isn’t a no standard of care treatment for platinum agnostic ovarian cancer, how should we think of the efficacy bar in this population to inform the next step?

Anna Berkenblit — Senior Vice President, Chief Medical Officer

Yeah. So, as a reminder, last year, Lucy Gilbert in ASCO presented data for the platinum agnostic cohort of mirvetuximab plus Avastin. And in the FR alpha high populations confirmed overall response rate was 64% in patients with platinum-resistant disease so that subset the response rate with 59% and in the platinum-sensitive recurrent subset, it was in the high-60s. Both of these numbers — response rates compare favorably to what you would see the standard of care in these populations. So, for Avastin plus chemotherapy, the confirmed response rate is 27%, 28%. So the mirvetuximab plus Avastin data look quite nice relative to that platinum-resistant disease.

Turning to recurrent platinum-sensitive disease, with platinum-based doublets, with just one prior line of therapy, you typically get a response rate in the low-50s. And so, our response rate in the 60s is quite nice when you think about the fact that we’re not exposing patients again to platinum-based therapy. So, I think this will give us really some nice options to consider as we think about the formal label expansion, and in the meantime, as you heard from Mark, we’ll be solidifying the approach for Compendia Listing.

Yige Guo — Guggenheim Securities — Analyst

Got it. Thanks, Anna. And then the next question, 632. You said you enroll up to 20 frontline patients to clear bar of 10% CR or CRI. Can you maybe elaborate a little on the potential scenario that you don’t need to enroll all 20 patients to meet the primary endpoint? Or in other words, what would be the minimum number of patients you need in this cohort?

Anna Berkenblit — Senior Vice President, Chief Medical Officer

Sure. I would point you to Alzheimer’s as a relevant regulatory precedent. When you look at their label, you will see that they received full approval based on their CR, CRC rate in 13 frontline BPDCN patients.

Yige Guo — Guggenheim Securities — Analyst

Got it. That’s helpful. That’s all for our questions. Thank you very much.

Operator

Thank you. Our next question comes from Boris Peaker from Cowen. Your line is open.

Boris Peaker — Cowen and Company — Analyst

Good morning. My first question just wanted to ask for mirvetuximab. Can you talk about the manufacturing, specifically where is it manufactured and which companies are involved? And what other steps are required to doing manufacturing, whether it’s assay validation or any kind of studies prior to submitting the BLA?

Mark Enyedy — President and Chief Executive Officer

Sure. So, you all recall the three components to an ADC together with the conjugation step to bring each of those components together. So the antibody is produced by Boehringer Ingelheim, the linker is produced at SAFC, Sigma-Aldrich and the payload is produced by [Indecipherable] and then we use BFT for the conjugation steps. So, we’re in good shape in terms of validation for mirvetuximab. We have all of the relevant assays in place. And so, we should be in good shape in terms of — at the time that we’re ready for inspection following a BLA submission for this facility.

Boris Peaker — Cowen and Company — Analyst

Great. And my last question is on 632 in BPDCN. I’m just curious kind of what your take is on how to compete with Elzonris commercially if approved.

Mark Enyedy — President and Chief Executive Officer

Yeah. We would continue to — I think on the basis of the key parameters of pharmaceutical commercialization. So, those are efficacy, safety, patient convenience. And think that based on the data we generated today we’re going to compare quite favorably, particularly as it relates to safety and convenience looking at their label versus the data that we’ve generated to date, all the relevant parameters there you think tilt in our favor based on the data we’ve generated to date.

If you look at Elzonris, a patient is required to be admitted into hospital for at least five days to initiate therapy, treatment with 632, the [Indecipherable] outpatient infusion. So, on all those parameters, the emerging profile we see and we think will compare quite favorably. And that would be the basis for competition.

Boris Peaker — Cowen and Company — Analyst

Great. Thank you for taking my questions.

Operator

Thank you. Our next question comes from Andy Hsieh from William Blair. Your line is open.

Andy T. Hsieh — William Blair & Company — Analyst

Oh, great. Thanks for taking my questions and very much look forward to a very eventful 2021. So, I just have a couple of questions for Anna in terms of kind of framing expectations for ASCO. So, first off, would this be the same 60 — roughly 60 patient population with longer follow-up at ASCO this year [Phonetic]?

Anna Berkenblit — Senior Vice President, Chief Medical Officer

Yes, Andy. So, I probably should have mentioned that when the previous question was asked. Yes, it’s the same number of patients. And what you will see in addition to ORR data, which we shared last year, you will now see duration of response data and PFS data now that we’ve been following patients for a longer period of time. We remain quite encouraged about the potential with the combination.

Andy T. Hsieh — William Blair & Company — Analyst

Great. Great. And do you mind reminding me, so I believe there were about 40% of the patients who had previous Avastin. Did you see a higher efficacy activity in Avastin-naive patients among the 60 enrolled?

Anna Berkenblit — Senior Vice President, Chief Medical Officer

When we look at that, Andy, it was kind of hard to tease apart because Avastin use was also correlated with the number of priors. So, given the small data set, you couldn’t take them apart.

Andy T. Hsieh — William Blair & Company — Analyst

I see. Okay. That’s — yeah, that makes sense. And then for the two ISTs, I didn’t really catch that. So did you say that the 145 patients and then 70 patients as you — did you say those are progressing well and could have data soon?

Anna Berkenblit — Senior Vice President, Chief Medical Officer

So these two ISTs are for mirvetuximab plus carboplatin. We have very encouraging data from our Phase 1 dose escalation study for the doublet. It looks basically like the mirv, carbo doublet performance like you would expect for a platinum-based triplet without the bevacizumab. So, on the basis of those encouraging preliminary data, two investigators came to us with ideas for further exploration of this mirv, carbo doublet. The first is Dr. Harter in Germany. We’re working with the AGL and they’re doing a randomized Phase 2 MIRV plus carbo, mirvetuximab continue to held back at maintenance driven [Phonetic] standard platinum-based therapy with or without maintenance in recurrent platinum-sensitive setting. And that study is getting up and running.

Similarly, Rebecca Arndt [Phonetic] at Ohio State came to us with the neoadjuvant concept that’s being run in several sectors in the US here, and this is really the first opportunity for us to get mirvetuximab into the frontline setting. And so, that’s a 70 patients really a feasibility study with some translational and correlative science built in and that also is getting up and running. I think I can’t speak for the investigators regarding when data will be available.

Andy T. Hsieh — William Blair & Company — Analyst

Okay. Got it. That’s helpful. Thank you very much.

Operator

Thank you. Our next question comes from Kennen MacKay from RBC Capital Markets. Your line is open.

Kennen MacKay — RBC Capital Markets — Analyst

Hi. Congrats on the progress in 2020 and thanks for taking the question. I guess, first I would…

Mark Enyedy — President and Chief Executive Officer

Hi, Kennen.

Kennen MacKay — RBC Capital Markets — Analyst

What to understand how are you thinking about sort of a commercial build ahead of anticipated BLA filing in sort of the back half of the year if you’ll be returning to sort of the pre-hiring strategy utilized previously, or again just how you’re thinking about that?

And then secondly, ahead of the IND for 151, just wanted to sort of understand your perspective on the unmet need that antibody is addressing versus MIRV or other prior full-targeted ADCs or small molecules? Thanks.

Mark Enyedy — President and Chief Executive Officer

Sure. I’ll start with the commercial planning then hand it over to Anna start [Phonetic] fill on 151. So, this is a relatively concentrated market, Kennen, when you think about physician targets and referral patterns and the like. And so, we think that the commercial — the investment required to support a robust launch will be well within our ability to finance and manage. And so, our efforts at this point are concentrated more on market research understanding, physician-patient segmentation, where these patients are, payer mix, those kinds of issues. And once we have the benefit of the survey or readout, we would move in earnest in terms of recruiting a sales force, sales management and the like. In parallel with that, we, of course, are developing a distribution plan. Again, working with some outside support to define how we will approach distribution. Again, with the goal of lining up vendors that we could move forward to definitive agreements with post the SORAYA readout.

So, as we think about spend for this year, we will see some expenditures in the earlier part of the year as we work through some of these planning exercises. And then the significant expenditure with the benefit of a positive readout and certainly ramping heavily in the fourth quarter of this year in anticipation of the filing and approval in 2022.

So, let me just pause and ask me any follow-up there, and if not, I’ll turn it over to Anna.

Kennen MacKay — RBC Capital Markets — Analyst

No, that’s really helpful. I appreciate that color. Thank you.

Anna Berkenblit — Senior Vice President, Chief Medical Officer

So turning to IMGN151, which is our next-generation Vidaza [Phonetic] topic FR alpha-targeted ADC, we’ve really designed it to address a broader population of FR alpha positive tumors. And we’ve done that by targeting two separate epitopes on folate receptor alpha, which allows greater internalization events and greater cell killing. We also have a stable linker peptide combination that allows for even greater stability in the circulation than with mirvetuximab. And the payload itself, DM21, is a bit more hydrophobic. So once the ADC is internalized, you get even more bystander killing, which can help with some of the heterogeneity of FR alpha expression. So, with that in mind, we anticipate that IMGN151 can address the broader population of patient [Technical Issues] alpha positive tumors, so not just the 40% whom we know benefit from mirvetuximab but with FR alpha high expression, but also the 40% additional FR alpha positive tumors with lower, medium expression because we know about 80% FR alpha — ovarian cancers half FR alpha expression. That should really double the population for ovarian cancer.

And then moving to other tumor types, endometrial cancer, triple-negative breast cancer and lung cancer. It’s a little premature to say what the appropriate cut off will be for those indications for patient selection, but we’re confident given the preclinical data we’ve generated thus far that potential for IMGN151 is much broader than that of mirvetuximab.

Kennen MacKay — RBC Capital Markets — Analyst

Got it. Thank you.

Operator

Thank you. Our next question comes from Jessica Fye from J.P. Morgan. Your line is open.

Luke Brennan — J.P. Morgan — Analyst

Good morning. This is Luke on for Jess. Thanks for taking our questions. I guess to start. Can you give us an idea of what sort of level of detail we can expect between the top line readout for SORAYA in 3Q versus data coming later this year?

Anna Berkenblit — Senior Vice President, Chief Medical Officer

A little a little hard to say right now, Luke, because we are able to pretty accurately assess when we’ll have sufficient data for confirmed overall response rate by investigator, which is our primary endpoint. Duration of response, as you know, needs to mature over time and the better patients are doing on mirvetuximab in SORAYA, the longer the median duration of response will be. And so, when we have material data we will share it.

Luke Brennan — J.P. Morgan — Analyst

Okay. And then also, is there any additional color you guys can give us on the Huadong licensing fee? Should we expect that to be amortized sort of over the entire year, longer than that, shorter than that? When can we see those revenues totally recognized?

Susan Altschuller — Senior Vice President and Chief Financial Officer

Yes. As we mentioned in our filing, the $40 million Huadong upfront license fee will be recognized over time as clinical supply requirements are delivered. So, our 2021 revenue guidance includes an estimated amount of the fee that will be amortized based on the current supply plan. Our estimate would be that potentially up to half of the fee could be recognized in 2021. But again, it’s dependent on the supply plan, which will continue to be refined as Huadong determined its regulatory strategy.

Luke Brennan — J.P. Morgan — Analyst

All right. Thank you very much.

Operator

Thank you. And our next question comes from Biren Amin from Jefferies. Your line is open.

Biren Amin — Jefferies & Company — Analyst

Yeah. Hi, guys. Thanks for taking my question. So, may be just one more on IMGN151. I think, with this compound, you’re also seeing an increase in conjugate exposure by 40% over MIRV. And I think this has also a higher half life than MIRV. So, Anna, maybe how do you — how are you thinking about the safety profile of 151 as it compares to MIRV, in particular the ocular tox as you file the IND by year-end?

Anna Berkenblit — Senior Vice President, Chief Medical Officer

Yeah. So, Biren, again, it’s a little early to speculate, but the ocular adverse events that are seen with tubulin-directed payloads, so including Abraxane and then ADCs with tubulin-directed payload, including auristatins and maytansinoids. I think it’s reasonable to anticipate that there will be some ocular adverse events with IMGN151 but it’s not clear to me that it’s linked in any regard to half-life specifically. So, I think we’re doing the preclinical data that we need to do to support the IND. And we’ve also really figured out how to optimally manage the ocular efforts and that’s mirvetuximab, so we’ll apply those lessons learned for — when we consider patient study designed in terms of lubricating eye drops and things like that.

Biren Amin — Jefferies & Company — Analyst

And maybe just a follow-up on that. Are you seeing anything in your preclinical animal model studies with 151 as it relates in comparison to MIRV in terms of just toxicity?

Anna Berkenblit — Senior Vice President, Chief Medical Officer

Not at this point.

Biren Amin — Jefferies & Company — Analyst

Great. Thank you.

Operator

Thank you. Our next question comes from Jonathan Chang from SVB Leerink. Your line is open.

Jonathan Chang — SVB Leerink — Analyst

Good morning and thanks for taking my question. Just one from me, given the proximity of the potential SORAYA BLA filing and the MIRASOL data readout, can you talk about the risk, if any, that the regulators may want to see the results of MIRASOL before potentially approving mirvetuximab?

Mark Enyedy — President and Chief Executive Officer

Yeah. We get this question fairly often. The answer is this, if the readout for SORAYA is positive and the data that meet the criteria for accelerated approval, which in this case would mean that the ORR and the DOR surpass that of available therapy. There is no basis for the FDA to delay regulatory action.

Jonathan Chang — SVB Leerink — Analyst

Got it. Thank you.

Mark Enyedy — President and Chief Executive Officer

Great.

Operator

Thank you. Our last question comes from Swayampakula Ramakanth from H.C. Wainwright. Your line is open.

Swayampakula Ramakanth — H.C. Wainwright & Co. — Analyst

Thank you and thank you for taking my question. Most of my questions have been answered, but just have a — trying to understand what your commercialization strategy is in Europe for both MIRA [Phonetic] and 632?

Mark Enyedy — President and Chief Executive Officer

Sure. So, in both cases, again these are highly concentrated markets, meaning the physician targets are limited. And so, the commercial investments are modest and certainly, something that we could undertake with our own financing. So, we are evaluating those markets. We have a little bit of time as it relates to mirvetuximab. We think that the EU will likely require the outcome of MIRASOL as a basis for approval. We’ll talk to them about the SORAYA data, but our expectation is, they probably will want results of a randomized controlled study to support approval. So, we will revisit this over the course of the latter part of this year and into 2020. But again, both of those products could be commercialized by ImmunoGen and we could support a robust launch in the markets in Europe.

Swayampakula Ramakanth — H.C. Wainwright & Co. — Analyst

Thank you, Mark. Thanks for taking my question.

Operator

Thank you. And that does conclude our question-and-answer session for today’s conference. I’d now like to turn the conference back over to Mark Enyedy for any closing remarks.

Mark Enyedy — President and Chief Executive Officer

Great. Well, thank you all for the questions this morning. We’re excited about the year ahead. And we’ll look forward to reporting our progress in subsequent calls and around our major data presentations. Thanks.

Operator

[Operator Closing Remarks]