Cartesian Therapeutics Inc (RNAC) 2020 Q4 法說會逐字稿

Good morning, and welcome to the Selecta Biosciences Fourth Quarter and Full Year 2020 Financial Results and Corporate Update Conference Call. (Operator Instructions) This call is being webcast live on the Investors and Media section of Selecta's website at www.selectabio.com, and it is being recorded.

For opening remarks, I would like to introduce Brad Dahms, Chief Financial Officer of Selecta. Please go ahead.

Thank you, and good morning. Welcome to our fourth quarter and full year 2020 financial results and corporate update conference call. The press release reporting our financial results is available in the Investors and Media section of our website, www.selectabio.com, and our annual report on Form 10-K for the year ended December 31, 2020, will be filed with the SEC.

Joining me today are Carsten Brunn, our President and Chief Executive Officer; Dr. Peter G. Traber, our Chief Medical Officer; and Kei Kishimoto, our Chief Scientific Officer.

During today's call, we will be making certain forward-looking statements, including, without limitation, statements about the potential safety, efficacy and regulatory clinical progress of our product candidates, financial projections and future expectations, plans, partnerships and prospects. These statements are subject to various risks, including those related to the COVID-19 outbreak that are described in our filings made with the Securities and Exchange Commission, including our most recent annual report on Form 10-K, which will be filed with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of today, March 11, 2021, and Selecta disclaims any obligation to update such statements even if management's views change.

I would now like to turn the call over to Carsten Brunn, our President and CEO. Carsten?

Thank you, Brad. Good morning. I appreciate you joining us today.

Over the past year, we have made several advancements for our ImmTOR platform to develop tolerogenic therapies designed to selectively mitigate unwanted immune responses and have achieved several key clinical, strategic and financial milestones that advance their pipeline and fit the table for an exciting year ahead.

We believe our clinical and preclinical candidates have the potential to amplify the efficacy of biologics therapies, including redosing of life-saving gene therapies as well as restore the body's natural cell tolerance in autoimmune diseases. We will continue to advance our pipeline and build momentum in 2021.

I'll start with our enzyme therapies programs. In 2020, we significantly de-risked the company through a strategic partnership with Sobi for SEL-212, and we've continued to make progress in getting SEL-212 approved to treat patients with chronic refractory gout. SEL-212 is comprised of ImmTOR co-administered with our proprietary uricase, pegadricase. There remains significant unmet medical need in chronic refractory gout with only a fraction of the estimated 160,000 patients in the U.S. receiving treatment with a currently approved uricase.

The DISSOLVE clinical program kicked off in the fourth quarter of 2020 and consists of 2 double-blinded, placebo-controlled trials of SEL-212. In December, the first patient in DISSOLVE I was dosed. DISSOLVE II was initiated in December 2020.

In both trials, SEL-212 will be evaluated at 2 doses of ImmTOR, 0.1 milligrams per kilogram and 0.15 milligrams per kilogram and one dose of pegadricase 0.2 milligrams per kilogram. Each trial aims to enroll 105 patients with 35 at each dose and 35 on placebo. Both trials have a 6-month primary endpoint of serum uric acid levels below 6 milligrams per deciliter at the 6-month time point, and only DISSOLVE I will have a 6-month extension for safety.

Secondary endpoints include gout flare incidents, tender and swollen joint counts, tophus burden, patient-reported outcomes of activity limitation and quality of life. Top line data from the DISSOLVE program are expected in the second half of 2022.

Based on learnings from the Phase II COMPARE study, we intend to enroll a higher proportion of patients with visible tophi. As you will recall, the delta of 19 percentage points was observed on SEL-212 reverses pegloticase for patients with visible tophi baseline on the primary endpoint, and only 41% of patients in COMPARE had visible tophi at baseline. We believe the proportion of patients with chronic refractory gout with visible tophi is closer to 60% to 70% of the patient population in specialty care in the U.S.

Our second indication in our enzymes program is IgA nephropathy, a kidney disease that occurs when immune complexes of an antibody called immunoglobulin A1 accumulates in the kidneys. Genetic or environmental factors that cause this abnormal IgA1 and its accumulation in the kidney can result in the development of IgA nephropathy, one of the most common causes of kidney disease.

Hypertension, proteinuria and decreased estimated GFR at the time of diagnosis are associated with poor prognosis. It can result in incremental loss of renal function and results in end-stage renal disease in approximately 30% to 40% of patients.

We will be researching a novel combination therapy by combining ImmTOR with an enzyme IgA protease. We are encouraged by published animal studies in which it has been shown to debulk the IgA1 immune complexes in the kidney, the root cause of IgA nephropathy.

A critical barrier to IgA protease development is the immunogenic bacterial origin of the protease. As demonstrated with SEL-212, ImmTOR has the ability to mitigate the formation of antidrug antibodies to immunogenic enzymes. We are moving forward with our IND-enabling work, and we expect to have an IND filed by the end of 2021, so we can commence our first clinical study in 2022.

With ImmTOR, we intend to develop a combination product candidate to treat the root cause of this disease in which there are currently no approved therapies.

A key objective of 2021 will be to generate our first human data for our gene therapy programs. Preclinical data of ImmTOR in gene therapy have demonstrated the potential to enable repeat dosing by preventing the formation of neutralizing antibodies, in addition to more durable and robust expression of the transgene after the first dose.

We recently commenced the Phase I first-in-human dose-escalation trial of SEL-399, which is a combination of an AAV8 capsid, containing no transgene in ImmTOR to further evaluate the ability of ImmTOR to mitigate the formation of antibodies to AAV8 capsid in use in gene therapies. The trial plans to enroll 45 healthy volunteers, randomized in a 3:1 ratio of ImmTOR plus empty AAV capsid to empty capsid alone. Preliminary efficacy will be measured by assessing levels of AAV-specific neutralizing antibodies and top line data anticipated in the fourth quarter of 2021. The SEL-399 study built on extensive preclinical data that have demonstrated the potential benefits of the ImmTOR platform in AAV gene therapy.

In the recent preclinical study in nonhuman primates, Selecta observed that co-administration of AAV vector and ImmTOR enabled higher and more durable transgene expression as well as robust inhibition of anti-AAV8 IgG neutralizing antibodies. Selecta intends to present its findings at the annual meeting of the American Society of Gene & Cell Therapy, ASGCT, in May.

The observation that co-administration of AAV vector and ImmTOR leads to higher transgene expression demonstrates the potential for dosing lower levels of AAV gene therapies when combined with ImmTOR, improving patient safety and lowering cost. Further long-term gene therapy data demonstrate that expression of systemic AAV gene therapies may wane over time, a limitation that ImmTOR has the potential to address.

Finally, AAV gene therapies cannot currently be redosed due to the formation of neutralizing antibodies to the AAV vector. In the study, ImmTOR mitigated the formation of these neutralizing antibodies in non-human primates, thereby potentially allowing for redosing another key unmet need in the gene therapy field.

Our results, along with previous studies, supporting the ImmTOR's hepatoprotective properties in liver injury model move us one step closer to transforming the lives of patients and realizing the full potential of gene therapy.

In collaboration with AskBio, we plan to initiate our clinical trial in patients for the treatment of methylmalonic acidemia, or MMA, in the second quarter of 2021. MMA is a rare monogenic disorder in which the body cannot break down certain proteins and fats. This metabolic disease may lead to metabolic crisis and is associated with long-term complications, including feeding problems, developmental delays, intellectual impairments, chronic kidney disease, optic nerve atrophy, osteopenia and pancreatitis.

Typically, well-managed patients have periods of relative health with intermittent metabolic decompensation events that may result in multi-organ failure triggered by intercurrent infections or stress episodes. Symptoms of MMA usually appear in early infancy and vary from mild to life-threatening. Without treatment, this disorder can lead to coma and, in some cases, death. We expect to report data on the first cohort of patients by the end of 2021.

In November 2020, we announced that the FDA granted orphan designation to MMA-101, which previously received Rare Pediatric Disease designation from the FDA in October 2020. This further underscores the significant unmet medical need that Selecta and AskBio are seeking to address with MMA-101. And we look forward to advancing this program in the hopes of helping patients affected by this rare metabolic disorder.

Now looking ahead, our proprietary gene therapy product candidate, SEL-313, is being developed to treat ornithine transcarbamylase, or OTC deficiency, and is expected to enter the clinic in 2022. OTC deficiency is an X-linked genetic disorder caused by genetic mutations in the OTC gene, which is critical for proper function of the urea cycle.

Individuals with OTC deficiency experience accumulation of excessive levels of ammonia in the blood. Severe symptoms include inability to control body temperature and breathing rate, seizures, coma, developmental delays and intellectual disability. Most approved therapies are focused on reducing the amount of ammonia in the blood and are not curative. Currently, the only curative approach is liver transplantation at an early stage, which can be associated with severe side effects and complications of lifelong immune suppression. We continue to work on the IND-enabling activities. And we'll share additional updates on this program later this year, including updates on our recently submitted Pediatric Investigation Plan to the European Medicines Agency.

Overall, ImmTOR holds significant promise and has the potential to be revolutionary for the gene therapy field. We're encouraged by the promising preclinical data and look forward to advancing these programs.

Before we wrap up on gene therapy, Sarepta continues to conduct preclinical work looking at the combination of ImmTOR in certain neuromuscular disorders, including Duchenne Muscular Dystrophy and Limb-Girdle Muscular Dystrophies.

If Sarepta exercises its option to enter into any commercial license agreements, we will be eligible for significant economics, including additional upfront, development, regulatory and commercial milestone payments as well as tiered royalties on net product sales. This agreement would further validate the potential of ImmTOR's platform to solve a critical hurdle in the gene therapy landscape, enabling redosing and giving more patients access to these powerful medicines.

Our autoimmune program is advancing through IND-enabling studies with an initial focus on primary biliary cholangitis. PBC is a chronic progressive autoimmune liver disorder that leads to inflammation, damage and scarring of the small bile duct. It has a well-defined target antigen, significant unmet medical need and is well suited to the application of our ImmTOR immune tolerance platform. Selecta expects to file an IND in PBC in 2022, and we look forward to providing additional updates on this program later this year.

Now I'll turn the call over to Brad to run through our financial results for the fourth quarter and full year ended December 31, 2020. Brad?

Thanks, Carsten. We had $140.1 million in cash, cash equivalents and restricted cash as of December 31, 2020, which compares to $147.6 million as of September 30, 2020. We believe our current liquidity position will be sufficient to meet our operating requirements into the second quarter of 2023.

Revenue recognition for the fourth quarter and fiscal year 2020 was $12 million and $16.6 million, respectively, which compares with $6.7 million and $6.7 million for the same period in 2019. The increase in revenue was primarily driven by the license agreement with Sobi resulting from the shipment of clinical supply as well as the reimbursement of costs incurred for the Phase III DISSOLVE clinical program.

R&D expenses for the fourth quarter and fiscal year 2020 were $15.1 million and $54.5 million, respectively, which compares with $15.2 million and $42.7 million, respectively, for the same period in 2019. During the quarter ended December 31, 2020, there was a reduction in expenses for the SEL-212 clinical programs due to the timing of the initiation of the Phase III DISSOLVE program compared to the Phase II COMPARE program in the prior period. This reduction was offset by increases in expenses incurred under the AskBio collaboration, combined with internal research and development to support our clinical programs. The annual increase reflects the initiation of the Phase III DISSOLVE clinical program. These costs are subject to the cost reimbursement arrangement under the license agreement with Sobi.

General and administrative expenses for the fourth quarter and fiscal year 2020 were $4.8 million and $18.9 million, respectively, which compares with $4.1 million and $16.4 million for the same periods in 2019. The quarterly and annual increase in expense was the result of increased patent and professional fees and facility and office expenses, offset by a decrease in travel expense.

For the fourth quarter and fiscal year 2020, Selecta reported a net loss of $15.4 million or $0.14 a share and $68.9 million or $0.68 a share, respectively, compared to a net loss of $14.9 million or $0.28 a share and $55.4 million or $1.22 per share for the same period in 2019. We have a well-defined work plan ahead of us with a clear priority of deploying our financial and operating resources to advance our product candidates in multiple indications.

I'll now hand the call back over to Carsten. Carsten?

Thank you, Brad. As mentioned earlier, 2020 was a transformational year for Selecta, and we're extremely excited about the continued growth of our company and confidence in our platform. I'd like to conclude by reiterating our gratitude to the many people who have been supportive along the way, including our patients and their families, our investigators and our great team at Selecta.

With that, we're happy to take questions.

(Operator Instructions) The first question comes from Kristen Kluska with Cantor Fitzgerald.

So the first question is, how might the initial trials you are conducting this year for gene therapy help you determine when might be the most appropriate time to potentially redose if successful? Do you think this is going to be viewed at more of an indication-by-indication basis or more of a patient-by-patient basis, especially if patients are dosed at different ages considering the benefits we've seen across the field when treated earlier?

Thanks, Kristen. That's an excellent question. So I think what we're trying to address initially is really the ability to redose, and that's defined as are we able to prevent the formation of neutralizing antibodies. And obviously, that varies very much by indication, but also patient to patient. If you look at specifically, pediatric indication, we believe there's a significant need there especially in liver-based applications.

We know that the liver grows up to 40-fold actually from birth to adulthood. So it develops obviously high likelihood that you have to redose. In other indications, it might be a couple of years before redosing, and we always reference the hem A data that is out there and where we saw after 3 to 4 years a decline of transgene expression.

So it really varies by indication, age of the patients and individual patients.

And then in your recent Science Advances publication, you highlighted that even a twofold decrease in vector dose could have a meaningful impact, both to safety and costs. But I wanted to ask how you and your partners are thinking about these potential advantages from a manufacturing standpoint?

Yes. So obviously, we're excited about our publication, Science Advances. And indeed, we believe if this translates into humans, would be a benefit on various fronts. A lower dose, obviously, brings lower safety concerns, which I think is a key driver in gene therapy but also a potential lower dose as well. And gene therapy manufacturing is a bottleneck and a key cost driver, and a associated lower cost of goods will be quite meaningful.

But obviously, we would have to see whether translates from the non-human primate into humans, but we're definitely encouraged by the data we have seen in non-human primates. Obviously, the increase in transgene expression is very relevant.

Great. And then a question for Brad. Could you remind us whether your cash guidance, if that's factoring in any potential milestone payments across your collaborations?

Yes. So it does not include any potential milestone payments, which would serve to extend our run -- serve to extend our runway on a nondilutive basis.

The next question comes from Raju Prasad with William Blair.

Congrats on the progress on the pipeline. Just wanted to see if you could provide a little more color on the dosing regimen for the ImmTOR and gene therapy. Can you talk a little bit about the need to dose ImmTOR at the first dose of AAV8?

And I think there's some discussion in some of the papers on the potential to increase transduction on the initial dosage? And then maybe, Carsten, if you could also comment on the potential to dose -- redose patients that have already received a gene therapy in another clinical trial potentially down the line?

Yes. Maybe I'll take the last question. That's a quick one. So if you have been previously exposed to an AAV gene therapy and you have not been dosed with ImmTOR, we don't address this patient population. So you have to give ImmTOR with the initial dose.

In terms of some color on the dosing, you're right. We saw a strong first dose benefit. So ImmTOR always has to be given with the first dose of AAV. And we're obviously looking now with the anti-capsid study to do a dose escalation. So we're testing, as you know, Raju, 3 doses of ImmTOR. We're starting with 0.15, 0.3 and 0.5 to see what the appropriate dose is. And obviously, we feel very confident with these doses since we have almost dosed 300 or almost 300 patients with ImmTOR in our gout program.

We've also seen in the non-human primate study that monthly, 3 monthly doses are of value as well. And obviously, we take all of this into consideration for the first human approach with MMA.

Great. And a quick follow-up. On the MMA program, have you disclosed the ImmTOR dose that you'll be taking forward in the clinical trial?

Yes. We haven't filed the IND. So we don't want to give guidance before the IND has been accepted. So we'll have to hold off on that. But it's in the dose range we've previously discussed. I think I can say as much.

Got it. And it will be -- the dose selection was independent -- is independent of the Phase I study results, I assume? Or will you be able to look at that...

Yes. Yes, that's correct. Yes. We -- yes, they are not necessarily sequenced. So we -- yes, we plan to run this in parallel. So it's independent of that, yes. I mean, obviously, if we have some learnings along the way, we'll incorporate them. But right now, they run in parallel basically or planned in parallel.

The next question comes from John Newman with Canaccord.

I also had a question on the work that you're doing in MMA with MMA-101. So I'm just curious, what you would be looking to potentially present in terms of preliminary data? Would you focus on hopefully the lack of formation of neutralizing antibodies? Would you tend to be able to talk a little bit about -- I don't know if you could get an initial efficacy read that quickly. But just curious as to what types of things you might be thinking about for the preliminary data for that program?

Yes, that's a good question, John. Obviously, I mean, we're always trying to address the underlying disease with gene therapy. So we're looking at, at least in the initial biomarkers of the disease, such as MMA levels. But as a platform company, of course, we're extremely interested in the neutralizing antibodies because we think that's an indicator for the ability to be able to redose.

And with the MMA-101 program, would you potentially look to explore redosing with this program initially? Or would that be something that perhaps you would look at in the subsequent trial?

Yes, that's a good question as well. We get a lot as well. I mean, I think we would initially here, look at the -- first, the efficacy of the gene therapy. Obviously, that's the key driver trying to treat those kids. And then we would see if we're able to prevent the formation of these antibodies as a good indication that we are able to redose, but it wouldn't be necessarily the heart of the first approach of the trial. Because it varies between kids when you have to redose. It will be a fairly lengthy trial.

Okay. Okay. And I just have one additional question, which is a broader question, and that is just wondering if you could talk about the existing partnership with AskBio and whether that would preclude you from -- if you would -- if you choose to, excuse me, to enter into additional partnerships. Obviously, you have the partnership with Sarepta, which is very interesting. But just curious if there's anything with the AskBio partnership that would perhaps maybe, to a small extent, limit other partnerships that you could enter into?

Yes, that's a good question as well. And obviously, as you know, John, we've been very selective in our partnerships, and we are -- we don't see any limitations on having additional partnerships. Just to kind of remind everyone, we have 2 partnerships with AskBio. We have a true strategic 50-50 collaboration, where we plan to co-develop and co-commercialize gene therapies.

The first indication is MMA. We've also licensed ImmTOR to AskBio for lead indication in Pompe disease. And then we have a research partnership with Sarepta, which is really focused on neuromuscular disorders. All the work we have done, John, is in liver-based diseases. But yes, I mean, they're -- I'm not sure, there's like 300, 400 different gene therapy monogenic diseases that can be addressed. So there's plenty of room for both inbound as well as outbound partnerships as well.

The next question comes from Difei Yang with Mizuho Securities.

Congrats on all the progress on gene therapy side. So just a couple of quick ones for the pediatric and adolescent gene therapies for MMA. Do you have a general sense throughout the patient's life how many times you might need me to -- or the patient might need to get retreatment?

Yes, I'll hand this question to our CMO, Peter.

Thank you, Carsten. That's a very astute question because the need for redosing really is quite -- going to be quite variable depending, as you say, on the age of the subjects, patients as well as the disease indication. And I think one needs to look at different indications as to what redosing might be required.

So for instance, in neuromuscular disease, say, like muscular dystrophy, where you're going to be treating young boys whose muscles will continue to develop, and you presumably will have to redose at a certain interval, which remains to be determined. Also, getting high levels of expression in, say, muscles might require a couple of initial doses, which could be considered if we were able to redose using ImmTOR.

In other disorders like metabolic disorders like MMA or OTC deficiency, it's really going to depend on how the liver grows and what the continued expression of the transgene is going to be and how that's reflected in their metabolic syndrome. So their metabolic syndrome could be improved for a year or 2 and then require redosing or it could be longer.

So it's really going to depend on the indication, the disease and the individual patient with regard to the effect that they get from the initial dose of gene therapy. So it's very clearly going to be complex. But the main issue is that if we have the opportunity to redose individuals, it's going to be a huge advantage to treating these genetic diseases.

So just moving on to from a strategic standpoint, we have been hearing all the AAVs, especially in hem A kind of situation, durability is -- the current construct are losing durability over time pretty quickly. So would you consider getting into hem A using the ImmTOR platform?

Yes, just want to remind -- sorry for that. Just wanted to remind everyone that we actually do have an existing partnership with Spark, and actually, Spark has exclusive rights to hem A.

But there's plenty other liver-based diseases that are of interest as well. So...

The next question comes from Chad Messer with Needham & Company.

Can we maybe revisit the ramping up for dosing in gene therapy as we're kind of get ready to get the clinical data later this year? I know we learned a lot from the 212 program and all the patients we dosed there. But how confident are you in the translatability of that data, which is in an enzyme over to an adeno viral vector and the dosing there was sub-chronic dosing for gene therapies, obviously, as we've discussed, different and potentially more complicated. Just wondering why and how confident you are in the translatability of that clinical data? And obviously, I'm sure you've got other evidence from preclinical studies and things, too.

Yes. Yes, that's a great question, Chad. And obviously, I mean, one of the key drivers, like I said, we have almost 300 patients dosed, is the large safety database that we have with ImmTOR with up to 6 months now. And in the Phase III, we're going to be dosing up to 12 months. So that definitely gives us confidence with -- on the safety side of things. We had significant interactions with the FDA around ImmTOR, which gives us confidence.

And then obviously, we're building on the preclinical data we have seen so far. And most recently, the non-human primate data, we're very encouraged we're able to prevent the formation of neutralizing antibodies.

I think one of the key differences, as you said, gout is kind of almost like a chronic intermittent treatment approach, gene therapy will be, obviously, much fewer treatments, which means you can potentially play with the dose of ImmTOR, which we're exploring with the anti-capsid study where we're looking at 3 doses of ImmTOR.

And then just to remind you, I mean, we have demonstrated in a number of different indication approaches that ImmTOR is pretty much agnostic to the antigen. So -- but obviously, the proof will be in the human studies, and that's really our key focus for 2021 to demonstrate that.

The next question is from Ram Selvaraju with H.C. Wainwright.

This is Boobalan dialing in for Ram Selvaraju. First of all, could you please comment on the enrollment status of the DISSOLVE trial? And do you plan doing interim analysis sometime in 2021?

Yes, that's a great question. So as mentioned, we've started both studies. We started DISSOLVE I in September, DISSOLVE II in December of last year. We are on track enrolling those studies, and we will be releasing top line data in the second half of 2022. And we don't plan to have any interim analysis at this point.

All right. That's understood. Regarding your collaboration with IGAN Biosciences, so what are some of the gating items that are remaining to advance the candidate to the human trials? And specifically, what metrics will be evaluated in doing this new process in addition to evaluating the candidate will not elicit immunogenicity?

Yes. I'll let Kei address this. And obviously, we have guided that we are currently doing -- work on the IND-enabling studies, where immunogenicity is a key driver, but I'll let Kei comment in more detail.

Sure. I'm happy to. Can you just repeat the question? I didn't catch the first part of it.

With respect to the collaboration with IGAN Biosciences, so I'm curious, what gating items are remaining to advance the candidate to the human trials? And what metrics will be evaluated during this new process in addition to evaluating whether the candidate will not elicit immunogenicity?

Sure. Yes. As you know, for filing the IND, we need to produce IND-enabling pharmacology and toxicology studies. So that will involve combinations of the IgA protease with the ImmTOR molecule.

Ultimately, though, I think our goal is to get into the clinic as quickly as possible because I think there's good pharmacological rationale based on published studies showing that the IgA protease can debulk IgA immune complexes in animal models. And as you know, we have a lot of clinical experience using ImmTOR. So I think that the combination makes sense because right now, the main limitation of IgA using IgA protease for the treatment of IgA nephropathy is the immunogenicity.

Okay. So moving forward with your MMA program. So I'm curious, what is the current standard of care for MMA? And how much it costs to treat an MMA patient in the United States? And what unique futures of MMA 1 (sic) [MMA-101] will accelerate its clinical development and market adoption?

Yes. I'll let Peter speak about this. But for me, really right now, the treatment options are fairly limited. And it's really -- it's liver transplantation is the only approach right now, and that oftentimes bears its own risks and limitations since you have to immunosuppress for lifetime, basically. But I'll let Peter talk, address this question. Peter?

Sure. The approach to MMA at this point is really diet, dietary restrictions, reducing the amount of intake of foods that can be -- that need to be metabolized by the pathway and then intermittently treating the episodes of metabolic crises that these children have, and general care beyond a liver transplant, which, although it doesn't completely cure the disorder, it markedly improves their outcomes. So those -- that's really the approach at this point.

In terms of the cost of care, I really can't give you a number for that. But I will say that these children are basically in intensive observation and care almost their entire lives with often stays in the hospital of up to months when they have metabolic crises. So the cost of care is enormous. I just can't put a particular number on it at this point.

That's understood. And one final from me. Do you think ImmTOR will be equally effective in mitigating immunogenicity regardless of the serotype of AAV vector being used?

Yes. I'll let Kei answer this. Obviously, we have done quite a bit of work, have been looking at various serotypes. Kei?

Sure. Yes. So we've looked at multiple serotypes, including AAV8, AAV5, AAV4 and KD. And really, it's consistent with our other preclinical data that ImmTOR's agnostic to the antigen. So whether it's an enzyme or a capsid or some other therapeutic protein or autoantigen, we've seen good preclinical data to support the mitigation of immunogenicity.

Congrats on the progress.

(Operator Instructions) The next question comes from Derek Archila with Stifel.

Sorry. This is Jacques on for Derek. I guess on your gene therapy programs, first, on MMA-101. How many patients worth of data should we expect? And then what in the biomarker data could we look to as signs of activity for the therapy? And then if I may, on your ongoing 399 study, other than antibody formation, what else are you looking to glean from the study that could help us further derisk the technology?

Yes. Thanks, Jacques, for the question. I'll let Peter once again handle this one to give a bit more color on the MMA study.

Okay. Thank you, Carsten. So for the MMA study, the efficacy endpoints that we're going to be looking at are, as Carsten mentioned earlier, are going to be biomarkers of enzymatic activity. So one of the obvious ones is MMA levels in the serum. But there is a very specific and -- test called propionic acid metabolism, which has been developed by our clinical collaborators at the NIH that will be used to measure activity of the enzyme. It's a very sensitive and validated test for looking at the enzymatic activity. And it's the enzymatic activity that is going to determine the clinical outcomes in the patients. So we'll be measuring both of those as endpoints in the initial trial.

The other aspect, of course, in an initial trial is safety, and we're going to be focused on that as well as the neutralizing antibodies and other immunologic T cell markers and so forth that might be affected by ImmTOR treatment. So it will be an extensive evaluation of both the disease as well as the immunogenicity.

And in terms of the anti-capsid study, in addition to the neutralizing antibodies, we'll also be looking at other immunologic biomarkers that we'll be looking at in an exploratory way. And then, of course, a key aspect of that trial will be safety. It's the first time that AAV vector has been administered with ImmTOR, and so that safety analysis will be -- will kind of set up future human trials as well.

Great. Congrats on the progress.

This concludes the question-and-answer portion of the call. I will now turn the call back over to Selecta's CEO, Carsten Brunn, for closing remarks. Carsten?

Thank you, operator, and thank you to everyone who joined us this morning. Please stay safe and healthy, and this concludes today's call. Thanks again.

The conference has now concluded. Thank you for attending today's presentation. You may now disconnect.