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Chimerix (NASDAQ:CMRX)
Q3 2021 Earnings Call
Nov 04, 2021, 8:30 a.m. ET

Contents:

  • Prepared Remarks
  • Questions and Answers
  • Call Participants

Prepared Remarks:


Operator

Good morning, ladies and gentlemen, and welcome to the Chimerix third quarter 2021 earnings conference call. I would now like to introduce you to your host for today's call, Michelle LaSpaluto, vice president of strategic planning and investor relations at Chimerix. Please proceed.

Michelle LaSpaluto -- Vice President of Strategic Planning and Investor Relations

Thank you. Good morning, everyone, and welcome to the Chimerix third quarter 2021 financial and operating results conference call. This morning, we issued our third quarter financial results press release and a separate release reporting positive top-line results from the ONC201 recurrent H3 K27M-mutant glioma. You can access those press releases in our Investor Relations section of the website.

With me on today's call are president and chief executive officer, Mike Sherman; chief financial and business officer, Mike Andriole; Allen Melemed, our chief medical officer; and Josh Allen, our chief technology officer of Imipridones. Before we begin, I would like to remind you that the statements made on today's call include forward-looking statements within the meaning of the Private Litigation Reform Act of 1995 and are subject to risks and uncertainties, and other factors. These risks and uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. Please refer to our filings with the SEC for a more complete disclosure of these risks and uncertainties.

At this time, I would like to turn the call over to Mike Sherman.

Mike Sherman -- President and Chief Executive Officer

Thanks, Michelle, and good morning, everyone. Thank you for joining us. We're happy to share with you today the positive top-line results from the blinded independent central review, or BICR of ONC201 in the treatment of recurrent H3 K27M-mutant glioma. This is really just a preview of the analysis that will be presented in a couple of weeks at the Society for Neuro-Oncology Annual Meeting in Boston.

You'll recall that we had worked with the FDA to define a cohort of patients that have the potential to form the basis of an NDA filing. These were the first 50 patients that met a very specific set of criteria across three different studies and two expanded access programs. The criteria were designed with two objectives in mind. The first, to define a homogeneous population of patients; and second, to select a group of patients in which tumor response could be assessed objectively with assurance that those responses were the result of ONC201 single-agent treatment alone.

On top of that, perhaps the most stringent response criteria was utilized at the FDA's request, the response assessment in neuro-oncology criteria for high-grade gliomas or RANO-HGG as it's commonly referred to. For those accustomed to resist response criteria, RANO-HGG represents a higher bar requires a tumor reduction of at least 50% in addition to clearing non-imaging hurdles, including stable or improving performance status and stable or declining use of steroids. So when you subject this analysis to a blinded independent central review, you're faced with a laundry list of reasons a response might not be confirmed. As we described in the past, the first 30 patients were evaluated previously with a single reader blinded review.

And the last 20 had been investigator assessed. From those assessments, we had a 22% response rate with a few more patients maturing. This blinded review was a fresh assessment of all 50 patients and included a two-reader assessment with a third reader adjudication when it was required. So you can imagine, we're pleased to report a 20% overall response rate with that criteria.

Allen will expand a little bit more on the approach for this protocol on this fresh assessment, which was really meaning a regulatory standard. It may be worth noting that the response rate in the first 25 patients enrolled for this data set recorded 20% and the second group of 25 also had a 20% response rate. While achieving any RANO-HGG response in this population of patients is not expected, we know the durability of response is also important. And these data are certainly compelling from a durability standpoint.

Responses emerge gradually as tumors tend to shrink over a period of months in response to ONC201. And among responders, the RANO-HGG hurdle of 50% reduction was achieved at a median of 8.3 months. On top of that, the duration of response was an additional 11.2 months. That translates to a median progression-free survival in responders of over 18 months, which is probably a better perspective on durability given the gradual onset of initial response.

And by the way, that's superior to the PFS among responders, we previously reported of just over 15 months. There are several details. We look forward to seeing presented at a plenary session during the upcoming SNO conference, which will build on this data. That includes the disease control rate, which includes patients with shrinking tumors who fell short of the 50% threshold.

And a few patients were indeed close. When you look at that disease control rate, roughly double the size of the response rate. We'll also report other forms of clinical benefit, which, as you might expect, were largely concentrated in those patients who achieved a RANO response or disease control. The presentation will also contain results of RANO low-grade glioma assessment referred to as RANO-LGG, which are quite consistent with RANO-HGG, further confirming the robustness of these findings.

The presentation will also include both PFS and OS analyses. A regulatory strategy has been to remain closely engaged with the FDA, and we will share this data with them as we continue our efforts on the ongoing clinical pharmacology studies and safety package covering a broader population of treated patients beyond the 50 in this analysis and CMC work. We don't see any of this as high-risk per se, but it is work that's necessary to advance to an NDA. Lately, there's been a series of complete response letters from the FDA on several other companies' NDAS and some of those CRLs are related to deficiencies in these areas, and we intend not to repeat those situations.

At the FDA's request, we're also gathering natural disease history data, which we expect to support the notion that the data we're seeing in this patient cohort is truly differentiated. At this point, my apologies to Dr. Melemed, as I probably already stolen the punch line of the data highlights, but I think he can provide some important context for these results. So let me turn it over to Allen.

Allen Melemed -- Chief Medical Officer

Thanks, Mike. It is indeed important to understand this patient population and the context for this treatment. First, all of the patients were in the current setting, which means that everyone's tumors had grown on one or more lines of that we received. All patients have received progression therapy.

In addition, the vast majority, almost 90% of patients also received temozolomide. Keep in mind that as H3 K27M gliomas are usually MGMT unmethylated, one would expect temozolomide to be less effective. The fact that so many patients had received temozolomide speaks to the fact that more options are needed for these patients. A second important point that Mike alluded to was the strict inclusion criteria agreed upon with FDA.

This was to ensure that any response we've seen were truly related to ONC201 as a single agent and not an artifact of radiation or another therapy. The study required at least a 90-day [Inaudible] from prior radiation, 23 days of temozolomide, 42 days for antibiotics, which most typically would be Avastin, and 28 days for other therapy. And it's hard to predict our response is that typically the initiation of treatment early in the course of disease. And you can imagine these restrictions and delays may not be the optimal disease setting for this treatment.

One I predict improved outcomes was the early use of ONC201, which is where we intend to focus our future development. These data are exciting, particularly in the light of the disease setting, we intend not to see RANO responses, and options are limited. This is based on accurate market research we performed during and prior to acquiring this pipeline of Imipridones, where key opinion leaders told us that a drug was providing a 20% response rate by RANO-HGG with at least 6 months durability would be clinically meaningful in this specific patient population. In this cohort, we're seeing durability of response roughly double this, which does not include the gradual onset to tumor response with a median onset of eight months.

Just to reiterate what Mike had said previously, the response and response determination was determined by a blinded independent central review. This review was performed with two independent readers with a third reader to adjudicate. This rigor is required for the purposes of regulatory filings. Regarding safety, the announcement was limited for this presentation, but you note there was one serious adverse event of pulmonary embolism, which is attributed as pause related to ONC201 by the investigator.

Our safety team assessed SAE as unlikely related in ONC201. Based on prior safety reviews, ONC201 has been found generally well tolerated during extended period of administration. The most commonly reported adverse events were nausea, vomiting, fatigue, and decreased lymphocyte counts. We're continuing to collect and assess the ongoing safety of over 200 patients as part of a package that we will plan to discuss with FDA.

We look forward to the complete presentation of this data in a couple of weeks at the SNO conference on the 20th of this month. The plenary session will also include additional supporting data, including evidence of disease control, clinical benefits, including changes by performance status, reduction in corticosteroids, RANO-LGG response as well as progression-free survival, and overall survival. These additional data in the context of the landscape of this disease found out the story of a drug that presents a potentially promising therapy for patients with this stable disease. The FDA has already granted ONC201 fast track designation for the treatment of adult recurrent H3 K27 mutant high-grade glioma, rare pediatric disease designation for the treatment of H3 K27 mutant glioma, and orphan drug designation for the treatment of glioblastoma and the treatment for malignant glioma.

With this overview and exciting clinical results, I'll now turn the call over to Mike Andriole for review of the financials. Mike?

Mike Andriole -- Chief Financial Officer

Thanks, Allen, and good morning, everyone. As Michelle mentioned in her introductory remarks, earlier today, we issued a press release containing our financial results for the third quarter of 2021. Starting with our balance sheet. We remain well capitalized and ended the third quarter with approximately $125 million in capital to fund operations.

We are adequately funded to achieve our upcoming milestones, and we expect a possible addition of nondilutive funding from a potential BARDA procurement contract will further strengthen our balance sheet. That said, we continue to be judicious with capital allocation across the portfolio. Cash burn was approximately $15 million for the quarter, up slightly from approximately $13 million in the second quarter of 2021. Turning to our statement of operations.

The company reported a net loss of $18.6 million or $0.21 per basic and diluted share for the third quarter of 2021, compared with a net loss of $11.4 million or $0.18 per basic and diluted share for the third quarter of 2020. Revenues for the third quarter of 2021 were $0.1 million, compared to $1.6 million for the same period of 2020. Research and development expenses increased to $13.8 million for the third quarter of 2021, compared to 10 million for the same period in 2020. The main driver of this increase is the incremental personnel and clinical expenses to support the addition of ONC201 to the pipeline.

General and administrative expenses increased to $4.9 million for the third quarter of 2021, compared to $3.2 million for the same period in 2020. Loss from operations was $18.6 million from the third quarter of 2021, compared to a loss from operations of $11.6 million for the same period in 2020. In accordance with the terms of the merger agreement between Chimerix and Oncoceutics, the achievement of the 20% overall response rate for ONC201 via BICR will result in a success milestone payment of $20 million to the former Oncoceutics shareholders to be paid prior to year-end. With that overview, I'll now turn the call over to Mike for closing remarks.

Mike?

Mike Sherman -- President and Chief Executive Officer

Thanks, Mike. Let me touch on our other programs before we open it up for Q&A. We're continuing progress with our Phase 3 clinical trial of DSTAT in newly diagnosed AML patients. To date, the enrollment of this study has proceeded more slowly than expected due to hospital staffing shortages, particularly nurses related to COVID-19.

For that reason, we expanded the number of sites included and are in the process of activating sites outside the U.S. to supplement enrollment. We expect to complete enrollment of the first 80 evaluable patients to take place in the second half of next year. With the approval this summer of Tembexa as a medical countermeasure for smallpox, we were pleased to see the FDA follow that up with a publication highlighting the risk-benefit of this drug in this indication.

It was a very thorough piece of work in which they highlighted the breadth of potential use across age groups, the simple short oral administration, the flexibility of having both tablet and suspension formulations, and the attractive resistance profile. They also summarize rationale for the potential combination of Tembexa with the existing approved countermeasure as an even more potent therapeutic option. Of course, the support within the U.S., particularly at BARDA, has always been high, but publications like this may be helpful as we reach out to other geographies for potential stockpiling. In the meantime, we can confirm our fill/finish and packaging processes have advanced such that we're positioned to be able to ship into the U.S.

stockpile immediately following execution of a procurement agreement, and then we stand ready to respond quickly to the expected RFP. At the annual BARDA industry days event on Wednesday, BARDA spoke of the relationship with Chimerix and success of having a second antiviral approved, and the importance of having more than one drug in the case of an outbreak. In addition, yesterday, we participated in the World Health Organization Advisory Committee on variola virus research, giving an update on Tembexa. Let me wrap up my comments by expressing our most sincere thank you to the clinical collaborators and their patients who participated in our clinical trials with the hope of improving not only their own outcomes, but also the outcomes of future patients.

I know companies make this comment somewhat reflectively. But when you personally witness the sacrifices, particularly the hospital staff have made during the pandemic, you can't help but be humbled by their energy and support. With that, operator, we'll now open the line for any questions.

Questions & Answers:


Operator

Thank you, sir. [Operator Instructions] Our first question comes from Maury Raycroft of Jefferies. Your line is open.

Maury Raycroft -- Jefferies -- Analyst

Hi. Good morning and congrats on the update today. Thanks for taking my question. To start, I'm wondering if you can talk more about the data set and provide any specifics on whether there were new responses or deterioration from the prior data set?

Mike Sherman -- President and Chief Executive Officer

Well, yeah. So you -- yeah, you can imagine, given that this is a sort of top-line summary and we need to refrain from getting into the detail that will be presented at SNO based on our agreements with them, I will say that just in terms of the assessments that have happened previously and where we sat -- the 22% response rate is essentially where we were going into this fresh blinded assessment with a couple -- I guess, there were a few patients that were still maturing. One, looks like with declining tumor volume had the potential to achieve that. And I'm not sure the outcome of specific patients in that regard.

But I do know that relative to that analysis, I believe we lost one -- I'm sorry, we lost two and gained one relative to the prior assessments of both the single reader blinded review and the investigator assessments. And what we had noted previously is there were a couple that were quite close to this 50% threshold that we knew could be subject to redifferences. In fact, when we see the -- and you'll see this in the waterfall plot when it's ultimately presented, there are actually a few patients that are quite close to the 50% threshold that just below it, that would be included in the disease control rate or shrinking disease. It's worth noting that those patients in that middle ground between zero and a 50% reduction, several of those patients were extended stable disease also had accompanying forms of other clinical benefits.

So you know those patients are benefiting. They're going home from their scans with shrinking tumors. And so it will be important, obviously, to see the context of all of those patients, both those achieving responses in those with extended stable disease.

Maury Raycroft -- Jefferies -- Analyst

Got it. OK. That's helpful. And when thinking about the new analysis on 201 in the total data set, I guess, how does that impact your view on expectations for the bar for success and for regulatory approval? If you can talk more about that.

Mike Sherman -- President and Chief Executive Officer

Yeah. And I'll let -- I'll make a brief comment and then let Allen chime in. We've -- when asked that question previously, we've always said, look, if the response rate dips down into the mid-teens, obviously, this becomes more challenging. That having been said, drugs for indications of this nature have been approved with mid-teens kind of response rate.

So hitting that threshold of 20% with this very robust sort of regulatory standard independent read is meaningful. It's meaningful for a couple of reasons. It was unprompted feedback from KOLs as we entered into this -- as we've done market research, suggest that 20% threshold was meaningful. Allen highlighted the six-month durability, which we will kind of blow that out of the park with this durability observed here, more than double that, not even counting the time that it took while the tumors were shrinking.

And I think the other important acknowledgment is the lower end of the confidence interval, given even a small data set of 50, you can put it at 10%. And so you can essentially rule out single-digit response rates where you would expect in this population, either zero or very low single-digit responses to any other therapy. The FDA has agreed that this is a patient population where current standard of care is palliated to. I probably said more than I planned to, Allen, but I don't know if you have anything, Allen or Josh, to add to that.

Allen Melemed -- Chief Medical Officer

The only thing I'll add is I do think it's really important to look at the context of what's available, and there's really not a lot of available therapies, and the therapies that are there really don't have a lot of responses. That is something that Mike has said, FDAs already acknowledged that palliation is an appropriate standard. So when you look at the whole package, you need to have responses that are durable with the safety package that is safe for patients. And I think this has a promising package.

Josh Allen -- Chief Technology Officer, Imipridones

Yeah. The only thing I'll add is the points that Mike and Allen both hit there were part of our conversations with FDA, just a reminder that the sample size of 50 was proposed to FDA in our discussions based on the expectation of continued observation of the 20% response rate, which, as Mike pointed to, provides you a lower bound 95% confidence interval of 10%. And in the context of that tallied up of available therapy that FDA acknowledged. And Allen just reminded you of -- all within part of the plan.

So this data is very much in line with our expectations that went into the selection of the sample size with our regulatory conversations.

Maury Raycroft -- Jefferies -- Analyst

Got it. It's all hope for perspective and congrats again and I'll hop back into the queue.

Operator

Thank you. And next, we have Joseph Thome of Cowen and Company. Your line is open.

Joseph Thome -- Cowen and Company -- Analyst

Hi, there. Good morning. Congrats and thank you for taking our questions. Maybe just the first one now that this data set is all set.

Can you kind of outline the cadence of interactions with the FDA that you expect likely probably to guess over the next few quarters here? And then second, just on the SAE. I know you indicated your internal team thought that it might not be related. Is there anything that you can share in terms of patient background or reason why you don't agree with the assessment of those additions? Thanks.

Mike Sherman -- President and Chief Executive Officer

Allen, maybe -- reverse order, do you want to address the SAE.

Allen Melemed -- Chief Medical Officer

I can take that. Yeah. So this SAE was seeing potentially related by the investigator. And this was initially evaluated by Oncoceutics as unlikely unrelated.

We did a reevaluation prior to the press release, and we completely agree that this is unlikely unrelated. The patient has multiple comorbidities, including obesity and other health areas that made this event likely unrelated to compound. Patient also was able to continue the therapy afterwards, again, making it unlikely and was unrelated. So there's a lot of factors here that our assessment was unlikely related to ONC201.

Mike Sherman -- President and Chief Executive Officer

I'll come back to the question of the FDA dialogue. We've established a collaborative dialogue with the FDA over the course of the summer and expect that to continue. We will share the full data being presented at SNO with the FDA in the coming weeks. And we also know that the FDA wants to see at least preliminary data from our ongoing natural disease history study.

And we've already have patients identified for that. And so that analysis is underway. This information, along with updates we provide on our clinpharm and CMC work over the next, say, six months, we'll inform their -- both their support to proceed with an NDA and how that should be executed. So including rolling submission versus full submission.

So that obviously impacts the timeline, which is why we've sort of not given more granular guidance on submission time frames. We expect to be in a position to get more specific on that timeline in the first half of next year. Hopefully, that helps.

Joseph Thome -- Cowen and Company -- Analyst

Yep. That is perfect. Thank you very much.

Operator

Thank you. We have Naureen Quibria of Maxim Group. Your line is open.

Naureen Quibria -- Maxim Group -- Analyst

Thanks. Hi, good morning. Congrats on the data. So I guess just starting off first with ONC201.

You've mentioned the natural history data. Do you have a sense of when you have some interim data on that, and you'd be -- it will be available this year with the public?

Mike Sherman -- President and Chief Executive Officer

Yes. I've had questions about that. There's maybe a perception that natural history data takes years to accumulate. And that's -- in this case, it's just not the case.

We've got a protocol underway and engaged to gather that data. We'll gather really two sets of data. Those that are aligned exactly with this 50 patient protocol, where we would expect to be able to confirm kind of zero or extremely low response rate and rare other forms of clinical benefit. And then we'll have a broader data set, which includes patients that maybe didn't meet those criteria for one reason or another, just to more broadly inform the drivers of survival or response in that patient group even outside of our -- that core set.

When I made the comment around the -- being able to provide more insight in the first half of next year, I think that coincides with at least our ability to have the first interim assessments of those analyses.

Allen Melemed -- Chief Medical Officer

And Mike, can I add one minor addition. I think no one believes that or [Inaudible] this population, in general, have a lot of responders. What we need to show is that the specific mutation doesn't have any differences. The mutation is relatively new and identified.

So that is what we have to show. I think when you look at recurrent diffuse midline gliomas, they're typically a lot of responders, but we need to show it with this specific mutation.

Naureen Quibria -- Maxim Group -- Analyst

That's helpful. Thank you And then with regards to the ONC201 study, obviously, this is the registration cohort of 50 patients. With regards to the remaining patients that are in the three other studies as well as the expanded program. When might you share data from the other patients, I'm just curious.

Allen Melemed -- Chief Medical Officer

Yeah. Let me take the first. I think one of the important reasons we did the analysis now, and as Mike had mentioned, we had a very mature data set with a long fall, I think, over a year and a half like 15 months. When you have a duration -- meet and duration response, our time to response at eight months, you need to have a very mature data set to show that you have what the response rate is as well as the durability.

So that is where the cut point was and why we use this for that. We are continuing to evaluate these patients, but I think our primary look will be this in order to discuss with regulators.

Naureen Quibria -- Maxim Group -- Analyst

OK. Great. And just one more from me. I think I sort of missed it.

This is with regards to Tembexa. And I was just curious with regards to new border contracts, so are you aware of any sort of delays across the board happening with new contracts? Do you have any sort of color on that?

Mike Sherman -- President and Chief Executive Officer

Well, we know the contracts group was sort of having it was challenged to kind of keep pace during the course of the summer. And then sort of that was really what had driven the delay in the first place. And really, that has no other drivers that I'm aware of. I can confirm as well that the potential hurdles related to budget negotiations or congressional debates around funding really don't have anything to do with this.

It's really just a logistical step that they need to get through. They've continually assured us of that. And so the best we can do and stand ready to respond to that RFP. We know that they're also -- BARDA is in a position that's actually kind of a different group that administers the contracts.

The BARDA group in particular, is ready to move very quickly once the RFP is enhanced so that we can get to a procurement contract. So we'll be able to do that somewhat quickly. Typically, that process takes a couple of months, but perhaps we can shorten it based on the sort of precedents that are out there that are pretty straightforward.

Naureen Quibria -- Maxim Group -- Analyst

Got it. Thank you. That's all for me.

Operator

Thank you. And next, we have Soumit Roy of Jones Research. Your line is now open.

Soumit Roy -- JonesTrading -- Analyst

Hi. Thank you for taking the question and congratulations on the very encouraging data. Wanted to check if these are confirmed response, if we can call it this -- with the RANO-HGG criteria if that's the way it goes. And I was a little confused on the 22% response rate you were mentioning.

How is that different from the overall 20% you are saying?

Mike Sherman -- President and Chief Executive Officer

Let me take that last point. And maybe, Josh, it's probably a good opportunity to sort of peel the onion back on sort of the robustness of these analyses. The 22% I referred to, essentially, we had 11 identified of the 50 in our prior presentations, where we had a blend of this single reader -- I think 30 of them were reviewed by a single-blinded reader. The others were investigator assessments.

And so we stood at essentially that 11 of 50 was where we were at prior to handing this over to the fresh blinded independent central review. So that -- and as I mentioned previously, from that analysis, I think net-net lost two of those and gained one as there were a few right around the 50% threshold. When you see the waterfall plot, I will repeat it, you'll see some patients that were quite close again. So this notion that to be able to stand up to repeated assessments and blinded reviews, and when you're going into a regulatory process, to know that, that at least 20% threshold that stood up to repeated examinations is comforting.

But maybe, Josh, describe a little bit more what's required in order to show a RANO-HGG response. And one thing, and maybe you can elaborate on, too, is that you often see other companies report data in gliomas and you see response rates that are higher and you scratch your head a little bit. And typically, those are not RANO-HGG responses. So now I'll let Allen -- or Josh, expand on that.

Josh Allen -- Chief Technology Officer, Imipridones

Yeah. Thanks, Soumit. That's a great point that Mike just highlighted. So the RANO-HGG criteria to qualify a response is among the most stringent of any response criteria.

So just to directly answer your question, yes, they are confirmed responses and more, and I'll explain a little more about that. So the 20% response rate is all by integrated RANO-HGG criteria. To qualify as one of those responders, you have to have a 50% regression on contrast-enhanced imaging confirmed on more than one MRI spaced at least more -- at least one month, if not more, apart from each other. So they're certainly confirmed from an imaging and in temporal perspective there.

In addition to that, the tumor must not be worsening on other MRI sequences, namely T2/FLAIR. In addition to those radiographic qualifications, there's clinical data as well. So you cannot have a decline in performance status measured by [Inaudible] or land peak performance status, and you cannot have an increase in corticosteroid use that can influence imaging artifacts as well. So if you think about it, it's really a very stringent criteria.

It's not only confirmation that's required here on imaging and confirmation on multiple imaging sequences and a number of different clinical data points as well that go into that overall picture. And that stands in contrast, more typical criteria that you might see and that Mike alluded to there, like RECIST criteria may be used to in other solid tumors.

Soumit Roy -- JonesTrading -- Analyst

Got it. And that's -- and you expect this would be the criteria FDA suggested? Or that's how you decided on the RANO-HGG.

Mike Sherman -- President and Chief Executive Officer

That's correct.

Allen Melemed -- Chief Medical Officer

This is Allen. FDA specifically asked us to do RANO-HGG. In addition, they wanted to evaluate these tumors by RANO-LGG. That wouldn't be the primary, but they wanted to evaluate that.

It's a little frustrating, we cannot share everything. We have to wait for the disclosure at SNO, but we will be also sharing the RANO-LGG, which is the low-grade component, which I can say is very consistent with what we're seeing with the RANO-HGG. So we're getting shrinkage, not just in the high-grade component of the tumors but the low-grade component as well.

Soumit Roy -- JonesTrading -- Analyst

Got it. And one last question. Just a little surprised at the late time to first response, 8.3 months. I was looking at the prior 30-patient the spider plot, it looks -- did not -- I did not realize it could be that late.

Is it because our second group of 20 patients were any way different than the first 30 patients? Or is it just how the data turned out?

Mike Sherman -- President and Chief Executive Officer

And I think that's pretty -- well, so there'll be sort of independent reads of all of those. So the individual curves may look a little different. But frankly, that phenomena was something that was observed in the prior published spider plot says, I can't remember exactly what the onset was. It may have been a little bit less than eight months, but it wasn't too far off of that.

Allen Melemed -- Chief Medical Officer

Can I just want to add in -- I'm sorry. I just want to add in context. It's not like the tumors weren't shrinking, weren't shrinking, and then finally shrunk is that they are gradually shrinking. So there are several points that they're going down, it took a while to get to that actual threshold of a 50% reduction.

So does that make -- so I -- they were having a progressive shrinkage, but it wasn't until eight months where they had the media announcement of the PR.

Soumit Roy -- JonesTrading -- Analyst

Thank you again for taking the questions.

Operator

Thank you. And next, we have David Nierengarten of Wedbush Securities. Your line is open.

David Nierengarten -- Wedbush Securities -- Analyst

Hey. Thanks for taking my question. So you talked about this combined therapeutic benefit or essentially, the tumors are shrinking for eight months, and then you have a median duration of response of 11 months. So we're correct in saying the kind of the median duration of patient benefit is 19 months? Or maybe if you could add any detail on kind of the median duration or time on therapy that the patient was having a benefit? And then have you discussed that kind of metric with the FDA and if that's part of the criteria for future approval here? Thanks.

Mike Sherman -- President and Chief Executive Officer

Yeah. I think you characterized it accurately that if you were to reflect on what's the really the patients experience and the patient benefit period where they're having, on average or median eight months of going home from their scans and finding that they were shrinking. And then to the point of 50% and then another 11 months median, where they stayed at least 50% or below the original size. So that is the experience.

If you add those two together is where you quoted the 19. I referred to a essentially a progression-free survival among responders, which is a similar number. The medians are calculated differently. So it ends up being about 18 months.

But indeed, that was discussed with the FDA as a relevant measure considering the late onset or the gradual onset is probably a better way to say it of response. So that's part of what would evaluate.

David Nierengarten -- Wedbush Securities -- Analyst

And if I recall, in some of the prior patient natural history that kind of a time to progression is more like 10 or 12 months? Or maybe you can remind us what the typical time to progression might be in these patients?

Mike Sherman -- President and Chief Executive Officer

Sure. I'll let Josh and Allen characterize that.

Josh Allen -- Chief Technology Officer, Imipridones

Yeah. Typical time to progression is usually from a median perspective on the first MRI. When you look at recurrent glioblastoma or other forms of diffuse midline glioma that have been studied. Keep in mind, this is in the recurrent setting, different from some of -- maybe the numbers you might be thinking of in the front-line setting after diagnosis.

So initiation from a therapy in the second line or later setting is typically around two months. In other words, on the first MRI. And if you look out the six-month landmark, that's typically less than 10% of patients that make it six months without progression when you think about a typical experience in current GBM or other forms of diffuse midline glioma.

Mike Sherman -- President and Chief Executive Officer

That's another, I think, point to highlight is the measures that were taken in order to assure that this response was sort of objectively assessed. And so these wash-out periods that Allen described, is not is not the optimal way to treat these patients clearly. I mean to allow months to pass after a potential progression to allow these other therapies to wash out. You'd much rather be treating either right on top of or on the heels of radiation treatment.

And of course, our future development will look at that. And so I think that's part of what you've got a 20% response rate in a challenging indication with really not the optimal treatment paradigm deployed, and I think all of those things considered, it sets the stage for a sort of options for patients as you move that treatment earlier, even higher response rates.

David Nierengarten -- Wedbush Securities -- Analyst

Thanks.

Operator

Thank you. No further questions in the queue. I will now turn it back over to Mike Sherman for closing remarks.

Mike Sherman -- President and Chief Executive Officer

Well, I just want to thank everyone for your time this morning and look forward to updating you again following the SNO conference. Thank you.

Operator

[Operator signoff]

Duration: 44 minutes

Call participants:

Michelle LaSpaluto -- Vice President of Strategic Planning and Investor Relations

Mike Sherman -- President and Chief Executive Officer

Allen Melemed -- Chief Medical Officer

Mike Andriole -- Chief Financial Officer

Maury Raycroft -- Jefferies -- Analyst

Josh Allen -- Chief Technology Officer, Imipridones

Joseph Thome -- Cowen and Company -- Analyst

Naureen Quibria -- Maxim Group -- Analyst

Soumit Roy -- JonesTrading -- Analyst

David Nierengarten -- Wedbush Securities -- Analyst

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