Despite Hitting Mid-Stage Trial Endpoint Goal, Vertex Strikes Out Rare Lung Disease Candidate; Stock Tumbles

Vertex Pharmaceuticals Incorporated VRTX announced the Phase 2 data evaluating VX-864 in alpha-1 antitrypsin deficiency (AATD) with the PiZZ genotype.
AATD is caused by changes in the SERPINA1 gene that encode the AAT protein. In the disease’s most common form, those changes cause the body to produce misfolded AAT protein in the blood, leading to liver and lung disease.
Though the treatment showed potential to increase plasma levels of fAAT protein, the magnitude of treatment effect observed in this study is unlikely to translate into substantial clinical benefit, the company said.
In the Phase 2 trial, treatment with VX-864 resulted in a mean increase of 2.2 to 2.3 micromolar in fAAT levels across three dose groups compared to placebo.
All dose groups showed a rapid increase in fAAT by Day 7, sustained over 28 days of treatment.
Similarly, significant increases in antigenic AAT levels were seen across the treatment groups, with a mean increase of 2.7 to 3.5 micromolar compared to placebo.
In October last year, the company discontinued another AATD program, VX-814, after investigators found “several patients” had elevated liver enzymes. Four f them having spikes more than eight times the upper limit of normal.
Having culled VX-814 and VX-864, the company will turn to its preclinical pipeline.
Price Action: VRTX shares are down 12.8% at $189 during the premarket session on the last check Friday.