Stealth BioTherapeutics Initiates Phase 1/2 Trial of SBT-20 in Patients With Early Stage Huntington’s Disease

Stealth BioTherapeutics Inc. (Stealth), a clinical-stage biopharmaceutical company developing therapeutics to treat mitochondrial dysfunction, today announced the initiation of CHALLENGE-HD, a Phase 1/2 trial evaluating SBT-20 in patients with early stage Huntington’s disease. SBT-20 is an investigational tetrapeptide aimed at improving mitochondrial function by restoring the physical and biochemical properties of dysfunctional mitochondria.

“Huntington’s disease is a fatal genetic disorder in which nerve cells in the brain deteriorate over time, causing patients to have progressively limited physical and mental abilities. Research shows that mitochondrial dysfunction may play a central role in this deterioration, making the mitochondria a prime target for study,” said Stealth’s Chief Clinical Development Officer Jim Carr. “This trial examines the safety and tolerability of SBT-20 at various doses, and begins to explore the possible benefit of the compound in addressing mitochondrial dysfunction in Huntington’s disease.”
CHALLENGE-HD is a two-part, randomized, double-blind, placebo-controlled trial being conducted at a single clinical site, the Centre for Human Drug Research (CHDR) in the Netherlands. The trial is evaluating the safety, tolerability and efficacy of daily subcutaneous injections of SBT-20 in adult patients with early stage Huntington’s disease (genetically confirmed disease with Unified Huntington’s Disease Rating Scale [UHDRS] Total Motor Score of five or more and Total Functional Capacity Score of seven or more). During part one, patients are administered SBT-20 subcutaneously for seven days at one of three ascending doses (5, 15 and 25 mg). The findings will be used to select a dose for the second part of the trial, in which SBT-20 will be administered subcutaneously for 28 days. The trial aims to enroll 24 patients, all of whom will participate in both part one and part two of the trial. The trial’s primary endpoints are safety and tolerability, and secondary endpoints will measure the effect of SBT-20 on mitochondrial and motor function as well as its pharmacokinetic profile.

“The initiation of CHALLENGE-HD is a significant milestone for Stealth as our second drug candidate enters human trials in a new therapeutic area. As a leader in mitochondrial medicine, we want to pursue the full potential of mitochondria-targeted therapies, in rare primary mitochondrial diseases, common diseases of aging and now in neurodegenerative disorders. We plan to use the results from this trial to better inform our SBT-20 pipeline development plan and the broader potential of our platform in neurodegenerative disorders,” said Stealth’s Chief Executive Officer Reenie McCarthy.