Michael Amoroso
Analyst · Cantor Fitzgerald
Thank you, Greg. Good morning, everyone, and thanks for joining us. We're all excited to be with you today, and I hope this call finds you and your loved ones safe in still uncertain time.
I'd like to begin this morning with a review of our 3 strategic priorities from this management team in 2021: first, bolstering our relevant operational experience, first and foremost for our management team, but also for our Board members; second, delivering operational excellence, both timely and fiscally disciplined to make sure we advance our clinical programs with meaningful data toward regulatory milestones; third, prioritizing, executing and advancing our preclinical pipeline towards the clinic, starting with a focus that we discussed on our last call on the eye or ophthalmic gene therapy programs.
Now that it's the midpoint of 2021, let's assess how we're doing. Priority 1, accomplished. We have added specific operational experience to our management team and our Board of Directors. As noted on our Q1 call, we enhanced our Board with the appointment of 4 new members. And most importantly, we strengthened our management team with the appointment of Dr. Vishwas Seshadri, who joined us from a senior level position at BMS to be our Head of Research and Clinical Development. In addition, we've added even more strength and experience to our clinical development program teams under Vish for EB and MPS. We've added relevant regulatory BLA experience, some of which has been paramount for our successful 2 Type B meetings over the last 6 months.
Also, we continue to fortify our quality and technical operations team in Cleveland as we move closer to the BLA readiness skill sets. All of these teams have been strengthened in 2021 thus far, and we will continue to be opportunistic about adding the best talent in the marketplace.
Priority 2, on target. We are delivering and have delivered operational excellence in achieving significant clinical milestones in a fiscally disciplined and timely manner. Let's start with our pivotal program in RDEB, EB-101.
I'm excited to tell you about the progress we made in patient enrollment, opening a second site for completing our registration trial and ultimately all driving towards a BLA in 2022.
I'm also excited to tell you about the progress made on our MPS IIIA program, which we had a successful and collaborative Type B meeting with the FDA last month, confirming that Transpher A is the pivotal study for ABO-102 in MPS IIIA.
Our third clinical program, MPS IIIB, we are at the conclusion of enrollment at the high-dose Cohort 3 level and will be concluding the Transpher B study for further approval. We'll continue to follow these patients to assess long-term safety and efficacy, specifically neurocognitive development over time.
And then priority 3, also on target. We are advancing our preclinical eye programs toward the clinic with great speed and precision. During Q2, we reported the results of 2 nonhuman primate studies. We are on track to begin proven concept studies in the second half of this year, and this will be toxicology study enabling into 2022 with some select ophthalmic indications.
Now let's take a deeper dive into the progress of our clinical programs and preclinical programs.
Starting with EB-101, our lead pivotal Phase III VIITAL Study for recessive dystrophic epidermolysis bullosa, or RDEB. We continue to build enrollment momentum in VIITAL. There continues to be high and growing level of interest among patients and health care professionals, and we are very pleased to have recently activated a second clinical trial site at UMass Memorial Medical Center in Worcester, Mass under principal investigator and world renounced EB expert, Dr. Karen Wiss. Dr. Wiss is a professional of Dermatology and Pediatrics at UMass Medical School, and she is the Director of Pediatric Dermatology. We are excited to have UMass team join Abeona's mission of pursuing a standard of care for large and chronic RDEB wounds.
This is a significant and major milestone, and I want to congratulate to you on this timely execution and thank the staff and team at UMass.
Now in addition to our lead trial site at Stanford Medical Center in Palo Alto, California, we can provide convenient treatment locations for study participants on both the West and East Coast, making travel logistics easier for patients and family.
I'll remind our investment community, this was one of the major challenges we heard from the community in 2020 and thus far, in '21, it seems to be opening up with our pandemic. The second site is paramount to our success.
At the same time, we're expanding necessary physician experience with EB-101 as we plan for potential commercial launch in the U.S.
We look forward to collaborating closely with the clinical team at UMass to screen in the enrolled subjects in VIITAL as soon as possible. They are ready to go.
Next, we continue our progress toward completing patient enrollment in the VIITAL Study. We have successfully administered EB-101 to patient #5. As you may recall from our last call, this is the patient who opted to rebiopsy and make new product. We are extremely happy to report that the rebiopsy and manufacturing of EB-101 product was successful for this patient, and they have received their EB-101 administration. The patient will be followed as per our VIITAL protocol. Additional patients continue to be identified and prescreened at both Stanford and now UMass to determine their eligibility for VIITAL. As a reminder, the target for the pivotal trial is the treatment of approximately 35 large chronic wounds across 10 to 15 patients. Today, I'm excited to report that we have treated more than half of the target number of randomized pairs of wounds thus far.
Next, let's turn our attention to our AAV platform, our second in-clinic program, ABO-102, the Sanfilippo Syndrome Type A or MPS IIIA disease.
Yesterday, we announced some very exciting news about our Type B meeting with the FDA for the MPS IIIA program. We had a successful collaborative Type B meeting and aligned with the FDA that the current single-arm Transpher A study will serve as the pivotal study for ABO-102 and potentially support a biologic license application, of course, depending on the data set.
Since 2016, we have now treated 21 patients in the Transpher A trial. We're excited about the safety and the magnitude of benefits seen with our investigational ABO-102 product in the younger children from the higher dose cohort as we reported at the World Symposium earlier this year.
We remain hopeful that if the more recently dosed children in Cohort 3 displayed similar treatment effects as those already presented, we could have evaluable data set in 2022. The patients we serve have tremendous unmet need. They cannot wait and we remain fully focused on operational excellence with the intent of now delivering 2 pivotal data packages in 2022, one for EB-101 and one now for ABO-102.
At the Type B meeting, we also align with the FDA on the definition of the primary endpoint for Transpher A, which is neurocognitive assessment using the raw score from the barely scaled infant and toddler development, and the Kauffman Assessment Battery for Children. These scales will be used in sequence. This is data we're already collecting as secondary end points. They will move to primary in Transpher A and Vish will tell you a little bit more about that shortly.
We are grateful to the FDA for their guidance, and we look forward to continuing to work closely with the agency toward our goal of bringing potentially life-saving therapy to patients afflicted with MPS IIIA.
In the near future, we intend to share the Type B meeting feedback with the EMA, followed by potentially other regulatory authorities around the world to guide our development plans for MAA in ex U.S. markets. Of course, the United States is our first focus.
In addition to the guidance and clarity from the FDA on the regulatory front, we also shared some very encouraging new clinical data from Transpher A that had not before been published this past weekend, during an oral presentation at the 16th International Symposium on MPS and related diseases, our new MRI data.
The data indicates that ABO-102 increases gray matter. Corpus callosum and amygdala volumes in the brain in 3 young patients with MPS IIIA at 24 months post treatment compared to an afflicted patient without treatment.
Now let's talk about this for a moment. Brain volume loss is characteristic in children with MPS IIIA, and it's associated with long-term cognitive and physical disability. Specifically, gray matter is important for cognitive development, corpus callosum for motor function and amygdala for fear learning as well as social and emotional development.
We're excited about the MRI data, as are our clinicians. And it's consistent with previously reported results of preservation of neurocognitive development in the 3 younger children that we -- in the 3 younger children from Cohort 3 that we have presented from Transpher A earlier this year with along its followup.
Moving onward to our last in-clinic program, ABO-101 in the Transpher B study for MPS IIIB. As noted on the last quarterly call, we reported results from Transpher B at the World Symposium in February. The results to date, Transpher B high-dose cohort, like the high-dose cohort in Transpher A show the drug is safe and well tolerated, eliciting a dose-dependent, sustained reduction in disease-specific biomarkers and demoting clear biologic effects.
As I reminded you in the past, we absolutely want to see biomarkers moving in the right direction. But the gold standard will be the collection of neurocognitive development data, and we need to let that mature into 2022.
Previously, we shared the accrual in Transpher B was paused after dosing 4 patients in the higher cohort because the drug product, again supplied by Nationwide Children's Hospital in Ohio, had reached its 2-year shelf life export. Some of our additional stability testing results showed specifications were not met for all parameters of Transpher B protocol. However, specifically physical titer.
However, after reviewing the test results based on equivalent potency, infectious titer, as well as the purity profile of the drug, the German Health Regulatory Authority, along with our DSMB, deem that the benefit of the drug outweighed the risk and endorsed the use of the product for those remaining patients with highest unmet need through the German name patient program. The MPP is a compassionate use program in Germany that allows individuals to be treated at the request of their treating physicians and families.
We're thankful for the authority and the DSMB actions acting quickly to get drug to these patients. To date, 3 patients have been dosed in the German MPP and a fourth is prescreened and getting ready for treatment. The total number of patients treated now at the higher dose, 1 times 10 to the 14 vector genomes per kilogram between Transpher B Cohort 3 and now the MPP program will soon be 8 children collectively.
In parallel, we're in the process of closing enrollment in the Transpher B study, and patients from both the Transpher B and the main patient use program will be monitored with the same rigor for ongoing safety and efficacy of the high-dose EB-101 product as they would have been within the Transpher B study.
While early biomarker das are promising, neurocognitive preservation and development is the gold standard as we discussed. We look forward to seeing 2-year neurocognitive data beginning in the first half of '22 for some of the first patients dosed in the higher dose cohort from Transpher B. And subsequently, we'll determine next steps for the program once we have some of these important and essential data points.
As we await these data, I'll remind you that out of our wholly owned Cleveland non-CDMO-dependent manufacturing facility, ABO-102 for MPS IIIA commercial-grade product is being made. Our experience in AAV production from our fully owned Elisa Linton Center will be highly transferable if and when we decide to manufacture EB-101 for MPS IIIB program, of course, data dependent in '22.
Finally, I'll give a brief update preclinical, and I'll open it up to the group for questions.
As previously noted, we conducted preclinical research with novel AAV capsids including our Abeona invented and partnered capsids in 6 undisclosed eye indications. These eye indications represent opportunities in the U.S. alone of about 5,000 to 15,000 patients with the highest unmet need. This continues our Abeona identity as a fully integrated end-to-end gene therapy company focused on high unmet needs.
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