Maze's APOL1 Kidney Drug Posts Impressive Data — Then the Stock Dropped 31 Percent
By FieldPulse Editorial · March 25, 2026
Tags: Clinical Trials, Pipeline
Maze Therapeutics reported a 61.8% reduction in proteinuria in a key patient subgroup for its APOL1 kidney disease drug — but investors punished the stock over trial size and competition from Vertex Pharmaceuticals.
Sometimes strong clinical data and a collapsing stock price arrive in the same press release.
That was the situation facing Maze Therapeutics on March 25, when the company reported Phase 2 HORIZON trial results for MZE829, its APOL1 inhibitor for APOL1-mediated kidney disease (AMKD) — and watched its market cap fall roughly 31 percent by the end of the day.
The data themselves were not the problem.
In the broad HORIZON trial population, MZE829 produced a 35.6 percent mean reduction in urine albumin-to-creatinine ratio (uACR) — a standard measure of proteinuria and kidney damage — at 12 weeks.
In the severe focal segmental glomerulosclerosis (FSGS) subgroup, the reduction jumped to 61.8 percent, a figure that Maze noted exceeds publicly available data for inaxaplin, the competing APOL1 drug being developed by Vertex Pharmaceuticals.
The market's reaction was driven by two concerns.
First, the FSGS subgroup that generated the most compelling efficacy signal included only 15 patients — a sample size that makes investors deeply cautious about drawing firm conclusions, regardless of how impressive the numbers look.
Second, Vertex casts a long shadow in this space.
As a well-capitalized competitor with an established rare disease commercial infrastructure, Vertex's presence in APOL1 kidney disease creates a competitive ceiling that makes investors skeptical about Maze's ability to carve out a viable market position even if the clinical data continue to hold.
AMKD disproportionately affects patients of West African ancestry who carry two copies of the APOL1 risk variant.
It is a significant driver of kidney failure in Black Americans and remains severely undertreated.
The scientific rationale for APOL1 inhibition is strong, and multiple companies have been racing toward proof of concept in this indication.
Maze said it plans to continue enrolling the HORIZON trial and advance toward a pivotal program.
For reps in nephrology or those tracking the rare kidney disease space, .
Source: https://www.biopharmadive.com/news/maze-positive-data-APOL1-kidney-disease-drug-vertex/815671/