Advancing AMT-130 for the treatment of Huntington’s disease
In October 2022, the DSMB reviewed all available safety, biomarker and imaging data from the ongoing Phase I/II clinical trials of AMT-130 and recommended resuming treatment at the higher dose.
As previously announced in August 2022, patient enrollment at the higher dose had been voluntarily paused following the reporting of suspected unexpected significant adverse reactions (SUSARs) in three patients shortly after they received the higher dose of AMT-130. The SUSAR events in all three patients have since fully resolved. The DSMB recommended implementing additional risk mitigation procedures during the first two weeks after the surgical administration of AMT-130, including a seven-day, in-person post-surgical visit. The DSMB also made no change to the treatment protocol regarding the use of immunosuppression that will continue to be at the discretion of the treating physician. The Company plans to resume patient dosing in the open-label European clinical study as soon as possible and complete enrollment in the first half of 2023. To date, 10 patients have been treated in the European study, including all six patients in the lower-dose cohort and four of nine patients in the higher-dose cohort. The Company still plans to announce one to two-years of follow up data from the U.S. Phase I/II clinical study in the second quarter of 2023.
All 26 patients have been enrolled in the first two cohorts of the randomized, controlled and double-blinded U.S. Phase I/II study of AMT-130, including 10 patients in the lower-dose cohort (6 treated patients and 4 control patients) and 16 patients in the higher-dose cohort (10 treated patients and 6 control patients). One control patient from the higher-dose cohort was successfully crossed over to treatment in the third quarter of 2022 and received the lower dose of AMT-130. In June 2022, the Company announced 12-month follow-up data from the lower-dose cohort of the U.S. Phase I/II study of AMT-130. The lower dose was generally well-tolerated with no serious adverse events related to treatment. In the four treated patients with evaluable data from this cohort, mean levels of mutant Huntingtin protein (mHTT) in the cerebral spinal fluid (CSF) declined at all timepoints compared to baseline and decreased by 53.8% at 12 months of follow-up. In the six treated patients in the lower-dose cohort, measurements of neurofilament light chain (NfL) in the CSF, a biomarker of neuronal damage, initially increased as expected following the AMT-130 surgical procedure and declined thereafter, nearing baseline at 12 months of follow-up.