LeonaBio Advances Brelgometon Into Adaptive Phase 2 ALS Trial Targeting H2 2026 Initiation

LeonaBio's planned Phase 2 study of brelgometon (ATH-1105) in ALS signals a shift in how adaptive trial designs and fluid biomarker endpoints are being structured for neurodegenerative indications, a design approach that regulatory affairs and clinical operations teams will need to track as the methodology gains traction across the sector. The company's CMO, Javier San Martin, MD, outlined the program at the 5th Annual ALS Drug Development Summit in Boston on June 4, 2026.

The planned study is a randomized, double-blind, placebo-controlled, dose-ranging proof-of-concept trial incorporating neurofilament light chain (NfL) as a validated pharmacodynamic biomarker alongside clinically meaningful endpoints. NfL's inclusion reflects a broader regulatory expectation that sponsors in neurodegenerative disease programs anchor efficacy signals to objective, quantifiable biomarkers, a consideration that aligns with ICH E9(R1) estimand frameworks and FDA's evolving guidance on ALS drug development.

Brelgometon is an oral, brain-penetrant small molecule designed to positively modulate the neurotrophic HGF system. LeonaBio completed a first-in-human Phase 1 double-blind, placebo-controlled trial (NCT06432647) in November 2024, enrolling 80 healthy volunteers across single and multiple ascending dose cohorts. Results demonstrated dose-proportional pharmacokinetics, confirmed CNS penetration, and a favorable safety and tolerability profile, the foundational data package required before advancing into a patient population with a median survival of two to five years from symptom onset.

For regulatory leads, the adaptive design element carries specific documentation implications. Adaptive Phase 2 protocols in rare, rapidly progressing diseases require pre-specified adaptation rules, clearly defined interim analysis triggers, and Type I error control strategies, all of which must be locked in the statistical analysis plan before first patient in. Any post-hoc modifications risk triggering additional FDA queries or protocol amendment cycles that could compress the development timeline.

The heterogeneity of ALS presentation, spanning both sporadic and familial forms, adds further complexity to endpoint selection and patient stratification. LeonaBio's integration of biomarker-driven endpoints alongside functional measures reflects an acknowledgment of that variability, and QA teams supporting the trial will need to ensure biomarker sample handling, chain of custody, and central laboratory qualification are addressed within the trial's quality management framework before initiation.

Phase 2 initiation remains targeted for the second half of 2026, with the protocol's adaptive methodology and biomarker integration strategy representing the key regulatory checkpoints between now and first patient enrollment.

Source: LeonaBio, Inc. via GlobeNewswire, June 4, 2026.