Dr. Walid Abi-Saab
Analyst · Stifel
Thank you, Matt. Good morning and good afternoon, everyone. I would like to start by reiterating that the recent feedback from discussions with the FDA does not change our mission. We strongly believe that AMT-130 represents the most compelling therapeutic data set generated in Huntington's disease to date and that these results provide the first clinical evidence that gene therapy can potentially alter the course of HD. As Matt noted earlier, we had a meeting where I had a Type A meeting with the FDA in late January. This meeting, we reviewed the previous FDA guidance and discuss key elements of our data package, including the statistical approach, construction of the natural history external control, biomarkers and clinical endpoints. We also shared with the agency additional sensitivity analyses and discussed additional data generation and considerations regarding the design of a Phase III trial. The official meeting minutes received from the FDA stated they cannot agree that data from the Phase I/II studies compared to an external control are sufficient to provide the primary evidence of effectiveness to support a marketing application. The agency also highlighted the absence of treatment effects relative to sham subjects in the U.S. Phase I/II study after 12 months. We respectfully have a different interpretation of these results than the FDA. In patients with early HD, 1 year is generally insufficient to reliably detect a meaningful progression of their disease. In the sham controlled portion of our U.S. study, control patients did not show clinical worsening after 1 year, making it virtually impossible to demonstrate any effect over that short period of time for a therapy designed to slow disease progression. To that end, evidence of disease slowing started to emerge in the second year of follow-up and has become even more pronounced in the third year. In rare diseases, where progression is slow, longer observation periods are required to demonstrate an improvement in the disease course. This is often addressed through comparison to well-characterized external controls derived from natural history data sets using statistical methodologies designed specifically for that purpose. There are multiple precedents where such approaches have supported regulatory approvals. Still, during the recent meeting, the agency strongly recommended we conduct a well-designed Phase III randomized, double-blind sham surgery-controlled study to demonstrate efficacy of AMT-130. We believe that a multiyear sham-controlled study could impose significant risks and burden to patients. Some might even consider it this trial design to be unethical. The HD patient community strongly agree with the sentiment and has communicated directly to the FDA on multiple occasions. These considerations warrant careful evaluation, particularly in the context of a rare, progressive and ultimately fatal neurodegenerative disease. Importantly, Huntington's disease is supported by 1 of the most comprehensive natural history databases and rare disease. Enroll HD alone includes more than 30,000 participants with high-quality longitudinal clinical data collected over many years through the extraordinary efforts of the HD community. We believe that this body of real-world evidence provides a strong foundation to inform efficient and scientifically rigorous study designs making a long-term sham-controlled study of a one-time administered therapy difficult to justify. We do hope that the FDA will be willing to work with us on ways to leverage this valuable natural history data to design an adequate and well-controlled Phase III study. We plan to request a Type B meeting in the second quarter of 2026 to further discuss potential Phase III study design in purchase that address the agency's feedback while also considering feasibility and patient risk. Additionally, we intend to amend and submit for review an updated statistical analysis plan for the ongoing Phase I/II study to include 4-year follow-up data compared to an external control. We believe extended observation has the potential to demonstrate continued durability and increased clinical meaningfulness of AMT-130 over time. Following unsolicited outreach by ex U.S. regulators after our 3-year data disclosure in September 2025, we have initiated regulatory discussions with several agencies. We will continue these discussions throughout the year and we'll provide an update once we have additional clarity on the regulatory pathway. We look forward to the opportunity to potentially bring forward our innovative treatment to patients outside the U.S. in an expedited matter. Meanwhile, we continue to analyze the large body of data we have accumulated with AMT-130. In February of 2026, just recently, we presented at the CHDI meeting in Folgwings, California, a new analysis showing that propensity score methodology using clinical covariants with TRACK HD and PREDICT HD data sets effectively substitutes for baseline stride volume in prediction of Huntington's disease progression. The Coveris use in these analyses were the same as those used in the 3-year analysis we shared in September 2025 to match AMT-130 patients to their counterparts and the external competitor cohort from the Enroll HD study. We continue to develop a manuscript with the complete results of our 3-year analysis and anticipate publication in the peer-reviewed medical journal later this year. Moving on to Fabry disease. In February, we reported preliminary safety and exploratory efficacy data from 11 patients in the ongoing Phase I/II trial of AMT-191, which was presented at the World Symposium in San Diego, California. As the cutoff date -- as of the cut update on January 8, 2026, all 11 patients in free dose cohorts exhibited elevated alpha-Gal A enzyme activity with 6 patients successfully withdrawn from enzyme replacement therapy. As of today, I'm pleased to report that all 11 patients have been withdrawn from enzyme replacement therapy. Importantly, dose-dependent elevation in alpha-Gal A enzyme activity were observed across the 3 dose levels. These increases were durable for the measured period of time, ranging from more than 1 year, the longest follow-up patient at the high dose to the shortest follow-up period of 4 months when the patients treated at the middle. Stable plasma lyso-Gb3 levels were maintained those dose across all those cohorts regardless of ART status through the cutoff date. AMT-191 continued to show a manageable safety profile. No serious adverse events related to AMT-191 have been reported in the mid- and low doses. 2 patients at the mid-dose experienced asymptomatic Grade 3 liver enzyme elevation. For protocol, any such grade 3 LFT increases are considered potential dose-limiting toxicity, which require review and confirmation by the independent data monitoring committee. Following such a review, these events were confirmed as dose limiting toxicity. And per protocol, we have paused dosing at the mid and high doses pending further evaluation. I'm pleased to report that both patients have responded well to corticosteroid therapy and are tapering off steroids with no loss of alpha-Gal A enzyme activity as of today. Turning now to AMT-260 for metal temporal epilepsy. 2025 was a productive year for the program. We shared data from a case study of the first patient treated with MT-160 with up to 6 months of follow-up presented most recently in September 2026 at the International League against epilepsy meeting in Lisbon, Portugal. Initial data showed a promising reduction in seizure frequency over the first 6 months with no serious adverse events. We have since completed enrollment of 5 more patients in the first cohort and begun enrollment in the second cohort. We expect enrollment to be completed in the second cohort by midyear. Additionally, we plan to provide an update in the second quarter on all 6 treated patients in the first cohort, including those with nondominant and dominant hemisphere lesions with at least 6 months of safety, tolerability and seizure frequency outcomes. I will now touch base on some additional pipeline updates. Phase I/II episode I trial of AMT-162 for SOD1 ALS remains on voluntary enrollment and treatment hold based on the recommendations of the independent data monitoring committee following a September 2025 review of preliminary data related to the safety and efficacy of AMT-162 in the context of a dose-limiting toxicity that was observed in 1 patient in the second cohort. This event of dorsal root ganglia toxicity resulted in a serious adverse event determined to be related to AMT-162. We will continue to collect data and evaluate data from the patients as they're being accumulated. Now I will turn over the call to Kylie to discuss our ongoing work with the HD community. Kylie?