Vertex Pharmaceuticals said it will halt development on investigational drug VX-864 after it failed to demonstrate enough benefit for patients with alpha-1 antitrypsin deficiency (AATD), a rare genetic disorder marked by a protein-folding defect that can cause liver and lung disease.

Phase 2 study results showed VX-864 increased functional alpha-1 antitrypsin levels in AATD patients across three dose types vs. placebo, but the company acknowledged that the treatment effect was unlikely to “translate into substantial clinical benefit.”

The study demonstrated for the first time that dosing of the small-molecule “corrector” caused significant increases in the mutant alpha-1 antitrypsin protein, said Carmen Bozic, Vertex’s chief medical officer.

Vertex plans to use the trial findings to develop alternate, small-molecule AATD therapies.