VectorY triples its PIONEER-ALS gene therapy trial to 36 patients

VectorY Therapeutics enlarged PIONEER-ALS, the Phase 1/2 trial of its drug VTx-002, from 12 to 36 participants, the company announced on 29 September 2026. The decision was taken before VectorY received any data relevant to efficacy, according to the release.

VTx-002 is a vectorized antibody: instead of infusing the antibody repeatedly, a gene therapy vector instructs cells in the central nervous system to keep producing it. The antibody targets the abnormal form of TDP-43, a protein that clumps inside motor neurons in most people with ALS. VectorY calls the approach first-in-class.

The trial is a global dose-escalation study testing two dose levels. The first US participant was dosed in February 2026 at the Sean M. Healey & AMG Center for ALS at Massachusetts General Hospital, and the first in Europe in September 2026 at University Medical Center Utrecht; sites in the UK are also part of the study.

Tripling the cohort gives the trial more statistical room for its secondary and exploratory measures: blood levels of neurofilament light, a marker of nerve damage, the ALSFRS-R functional rating scale, slow vital capacity, grip strength measured by hand-held dynamometry, and survival. No efficacy results have been reported yet.