Thank you, everybody. Joining me today is Dr. Eric Rose, our Chief Medical Officer, and Geraldine Storton, our Head of Quality and Regulatory Affairs. Today, we received complete response from the U.S. FDA for our BLA in steroid-refractory acute graft-versus-host disease in children. The FDA has informed us that they require more data to support marketing approval. To obtain the data that is required, Mesoblast will conduct a targeted, a very targeted, controlled study in the highest-risk adults with the greatest mortality. This adult study is in line with our overall commercial strategy, which has envisioned a sequenced progression from pediatric to the adult steroid-refractory GVHD indication. It is important to note that adults comprise the vast majority of patients with this devastating disease, 80% of the GVHD market. Importantly, FDA's inspection of our manufacturing process resulted in no observed concerns.
The agency raised no safety issues across more than 1,300 patients who have received remestemcel to date, and acknowledged that improvements to our potency assay are in place. We remain steadfast in making remestemcel available to both children and adults suffering from this devastating disease, and have received substantial clarity in how to bring this much-needed product to these patients. We intend to enroll adult patients at the highest mortality risk with steroid-refractory GVHD, where existing therapy has not improved outcomes and where 90-day survival remains as low as 20%-30%. Mesoblast has already generated pilot data through our emergency IND program in adults, showing a survival benefit with remestemcel in this target population.
In line with our overall commercial strategy to expand into the adult GVHD indication, Mesoblast has already been working with leading investigators across the United States, multiple academic centers of excellence, to establish the adult follow-on study protocol, potentially utilizing established clinical trials networks and their existing infrastructure. The company will seek alignment with the FDA on the trial design for the adult study at a Type A meeting within the next 45 days. Important to note that prior to the resubmission, FDA guided Mesoblast to resolve outstanding chemistry, manufacturing, and control, CMC issues, before initiating any clinical trial. FDA completed the pre-license inspection of the manufacturing facility during this review and did not issue any Form 483 and found no objectionable conditions.
In addition, FDA acknowledged in the resubmission review that changes implemented appear to have improved assay performance relative to the original version of potency assay used in the pediatric phase III trial. Important to remember that Mesoblast has successfully met the pre-specified primary endpoint, prospectively agreed with FDA of a single-arm phase III trial in 54 children with steroid-refractory GVHD. While the Oncologic Drugs Advisory Committee, ODAC, of FDA in August 2020, voted 9 to 1 in favor of remestemcel-L's efficacy in a pediatric patient population, in September of that year, FDA recommended that further steps be undertaken to obtain approval. The BLA resubmission earlier this year included long-term follow-up data from the phase III trial by the Center for International Blood and Marrow Transplant Research, CIBMTR, which showed that 50% of children survived through more than four years of follow-up, remestemcel-L from the phase III trial.
For whom, given the severity of the disease, less than 20% survival at 2 years was expected. The resubmission also included a post-hoc propensity-matched study, showing six-month survival was 67% with remestemcel in the highest-risk children versus 10% with other unapproved therapies. These pediatric data provide further support and provide confidence in the use of remestemcel in the proposed study in high-risk adults with steroid-refractory GVHD. On that note, I'd like to open it up now for Q&A, please.
Thank you.
Operator.
If you wish to ask a question, please press star one on your telephone and wait for your name to be announced. If you wish to cancel your request, please press star two. If you're using a speaker, please pick up the headset to ask your question. Your first question comes from Louise Chen from Cantor. Please go ahead.
Hi. Thank you for taking my questions and hosting the call. I wanted to ask you a few questions here on the adult trial. How many patients are you planning to enroll? How long do you think it'll take? You know, how much will it cost? You know, when will you have a sort of more definitive next steps on the rest of the pipeline? Thank you.
Sure. As I mentioned earlier, we will be having a Type A meeting with the FDA over the next 45 days. The precise protocol design, number of patients, and the primary endpoint, et cetera, will be discussed at that meeting. We're targeting serious patients who are refractory to all existing drugs or any approved drugs. For these adult patients, there is nothing approved, and the mortality is as high as 70%- 80% within a 2- to 3-month period. We already have data from our EIND program that shows that we have substantial survival benefit in these very, very patients. We have the approach statistically to predict the delta, the difference between treated and expected outcomes.
We expect that this study will be relatively small, and, and relatively easy to enroll. The exact numbers I'll, I'll, I'll come back to you with. In terms of funding, we are working with our academic partners across established GVHD bone marrow transplant networks, we expect this to be funded very much as an academic study. We already have inventory that is able to be, to, to be used. More detail around this, I think, will be forthcoming in the next 45 days plus.
Thank you.
Your next question comes from Edward Tenthoff from Piper Sandler. Please go ahead.
Hi. Yeah, thanks for taking my questions. I'm a little confused why you have to do a study in adults if this BLA submission was for children. Would a future potential approval be for adults and kids? Would it be just for adults? Any clarity that you have on that? Thank you.
No, FDA wanted to see more more data to confirm the results that we've outlined in the pediatric population. They have given us the choice whether we want to go into an adult study or another pediatric study. The objective, of course, is to do an adult study in very sick patients that would provide us approval in both adults and children.
Yeah, that makes sense. Would this be a placebo-controlled study, or what would be the control, or would it be single arm?
Well, there's not, there's not, there's no point in having placebo. These are patients who failed all available therapies. That's the discussion to have with the FDA. What is the appropriate what is the appropriate control for the treatment arm?
Okay, excellent. Thank you. Good luck.
Thank you.
Your next question comes from Sami Corwin, from William Blair. Please go ahead.
Hi. Thanks for taking my question. Did the FDA provide any color as to why the long-term data from the pediatric cohort wasn't sufficient, or why the comparison to the MAGIC cohort wasn't sufficient? I guess, what are the implications now for your other pipeline programs, such as your chronic low back pain program?
FDA would like to see controlled data to confirm the observations, both in the high-risk, highest-risk patients, with high MAP scores in children, as well as the long-term survival data. I think it's, it's clear that they would like additional data to get comfort that the product continues to demonstrate survival benefit in the hardest to treat, highest-risk patients. And, obviously, we, we have to ensure that we are substantially financially robust in order to ensure that we focus on the adult GVHD, the opportunity that is near term before us, and we will have to sequence our other programs appropriately and manage our resources appropriately. And we're doing our, our internal reviews as we speak.
Great. Thank you. Good luck.
It's, it's fair to say that the adult program remains our number 1 priority after the adult GVHD program.
Great. Thank you.
Your next question comes from David Stanton, from Jefferies. Please go ahead.
Good morning and good afternoon. Thank you very much for, for taking my questions. You've, you've talked to the, the adult trial, and you said that it's, you know, it's, it's a relatively small and might be easy to enroll. I mean, you know, it, given you've got a 40 days, 45 days before you start getting feedback on the, on the, on that trial, I mean, when might we start to... When might the trial start? Approximately how long will, will the trial take? Is it, is it an 18-month trial? Is it a 2-year trial? Can you sort of give us some color around that, please? That's my first question.
No, I think it was substantially shorter than, than, than what you're suggesting, but I think to be more precise, I need to come back to you as soon as I've had the, the meeting with, with the agency. We're, we're talking about patients who, having failed all available therapies, have a mortality of, you know, 70%, 80% at 90 days. These patients are not hard to enroll because there are no alternatives, it's really dependent on how many sites we bring up to speed as rapidly as possible across a network that could potentially have as many as 40 sites in it across the U.S.
Understood. I just want to confirm the answer to a previous question. You've, you've had feedback from the regulatory authorities that an adult trial, you know, could lead to an approval if it's positive, in both adults and children, please?
Yes. That's the, that's, that's why we would be doing an adult trial.
Understood. Thank you very much.
The next question comes from John Hester from Bell Potter. Please go ahead.
Yeah. Good, good morning, Silvio. Good morning, everyone. Silvio, I just want to go back to the October 2020 Complete Response Letter. In that letter, they, the FDA had required you to do remestemcel-L through an additional study. It's my understanding, it was market's understanding that an additional study has since been negotiated and was off the table. What's changed at the FDA that they now require this additional study?
That's a very good question. We went through a dispute resolution process where the outcome of that was that the potency assays needed to be improved. On completion of the assay development work, the pediatric data would be reconsidered in its totality. That was the whole basis of the resubmission. The, the, the, the, the improvement in the, in the potency assays has been acknowledged. The manufacturing process has, has been reviewed with no, no issues raised. We, we had fully anticipated that the additional clinical data, including long-term survival benefit, would be sufficient to allow a sequenced approach to the market, with the product being immediately made available to children who have nothing approved and who continue to have a very high mortality, whilst we moved forward with an adult program.
At all times, we had planned to initiate around this time an adult program with the improved potency and with manufacturing being, being, vetted effectively. In fact, FDA had told us that we couldn't begin a, a further trial until we had those things signed off. The review process has allowed us to have both manufacturing, through the inspection and the potency assays, in alignment with, with the agency, and we're now able to move into another trial. We had hoped, of course, that the pediatric population would have the product made available earlier than the adult population.
Yeah. Well, it just seems that the FDA keeps moving the, the goalpost here, which is incredibly hard to for you, let alone analysts, to deal with, I suppose, but it's, it's frustrating. In terms of other stuff, are you going to allow the expanded access program for pediatrics to continue in the U.S., or do you plan on curtailing that?
That remains an item to discuss with the agency when we meet with them over the next 45 days. We still want to see whether we can get a product to children in a faster timeframe than the completion of the adult trial. I think those discussions will continue very actively.
Is that, is that a piece of leverage that you have with the, the, the FDA?
Let's see how those discussions go when we meet. You know, we, we clearly would like to make this product available as quickly as possible to children, and that should not be impacted by the adult trial.
Yep. Finally, you've got $71.3 million of cash in the bank, and that sort of pluses some undrawn debt.
Yes. I think, I think I think we were just disconnected. John, if you dial back in. Please come back. Hello, operator?
Pardon me. The participant has disconnected. There are no further questions at this time.
Great.
That brings us to the end of today's call. I'll hand over to Dr. Itescu for closing remarks.
Thank you very much. I, I appreciate everybody coming on to this call in such a short amount of time, and we look forward to updating the market shortly after we've had our next meeting and discussions with the FDA. Thank you, everybody.