Vertex on Tuesday announced results from the mid-stage trial of its experimental pill, inaxaplin, in two groups of patients with APOL1-mediated kidney disease.

  • In people with modest proteinuria, albumin in the urine fell 42.7% from baseline, and total protein fell 44.7% in the study. 
  • A second group — people who also have type 2 diabetes — saw a smaller drop: 17.3% for albumin and 25.4% for total protein.
  • Truist called the data a validation of APOL1 inhibition in a potential market of more than 100,000 patients and said the opportunity is large enough to support blockbuster sales for Maze’s MZE829 even if it only matches inaxaplin.


Shares of Vertex Pharmaceuticals (VRTX) rose 3% on Tuesday after the company said its experimental pill inaxaplin cut protein leakage into urine in a study in two extra groups of patients with APOL1-mediated kidney disease (AMKD), a genetic condition with no approved treatments.

Rival Maze Therapeutics (MAZE), which is developing its own drug for the condition called MZE829, jumped more sharply, by about 25%, on the read-through.

Broader Patients, Similar Signal

The mid-stage AMPLIFIED study tested a once-daily 45 mg dose of inaxaplin for 13 weeks on top of optimized standard care. In people with modest proteinuria, urinary albumin fell 42.7% from baseline, and total protein fell 44.7%. That matched an earlier mid-stage study in patients with a scarring form of the disease known as Focal Segmental Glomerulosclerosis (FSGS). Most people in the new modest-proteinuria group did not have an FSGS diagnosis.

A second group — people who also have type 2 diabetes — saw a smaller drop: 17.3% for albumin and 25.4% for total protein. Vertex called that effect encouraging but more modest. The drug was generally well tolerated. No serious side effects were tied to inaxaplin; headache was the most common complaint.

AMKD is a rapidly progressing disease caused by two variants in the APOL1 gene and occurs mainly in people of African ancestry. Vertex estimates it affects about 150,000 people in the United States and Europe. Left untreated, it can lead to dialysis, transplant, or death.

Pivotal Study Now Fully Enrolled

Vertex also said it has finished enrollment in AMPLITUDE, the larger trial in patients with more severe proteinuria and no other major kidney-damaging conditions. An interim look is due in early 2027 and, if positive, could support a U.S. accelerated-approval filing. The company plans to discuss the AMPLIFIED results with regulators alongside that program.

Chief medical officer Carmen Bozic said the findings add to evidence that inaxaplin could become a first- and best-in-class therapy aimed at the disease’s root cause.

Analysts See A Bigger Market — And A Lift For Maze

Truist analyst Danielle Brill called the data a meaningful validation of APOL1 inhibition in classic AMKD and estimated an addressable population of more than 100,000 patients. Truist sees “a significant positive readthrough” for Maze. While it is too early to compare the two drugs, the firm said the opportunity is large enough to support blockbuster sales for MZE829 even if efficacy and safety prove only comparable to inaxaplin. Truist rates Maze a Buy with a $64 price target. The new price target implies a potential upside of about 186% from the stock’s last closing price on Monday.

How Did VRTX Retail Traders React?

On Stocktwits, retail sentiment around VRTX stock stayed in ‘bearish’ territory over the past 24 hours, while message volume stayed ‘low.’

Meanwhile, sentiment around MAZE jumped from ‘neutral’ to ‘bullish’ over the past 24 hours, while retail chatter jumped to ‘high’ levels.

VRTX stock is up about 15% year to date. MAZE is down about 35% over the same stretch, leaving Tuesday’s pop against a steep 2026 drawdown.

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