Otsuka kidney drug slowed loss of function, but less than expected, in late-stage trial

By Adam FeuersteinJune 4, 2026

Adam Feuerstein, a senior writer and biotech columnist, is the author of Adam’s Biotech Scorecard, a subscriber-only newsletter about the crossroads of drug development, business, Wall Street, and biotechnology.

Adam Feuerstein is a senior writer and biotech columnist, reporting on the crossroads of drug development, business, Wall Street, and biotechnology. He is also a co-host of the weekly biotech podcast The Readout Loud and author of the newsletter Adam’s Biotech Scorecard. You can reach Adam on Signal at stataf.54.Otsuka’s Voyxact slowed the loss of kidney function after one year in patients with a chronic autoimmune kidney disease, but the benefit was less than expected and left room for competing treatments to perform better.

In a Phase 3 study, patients with IgA nephropathy, or IgAN, who received injections of Voyxact saw their kidneys lose function at an annualized rate of 3 points over one year compared to an annualized function loss of 7.6 points over one year for patients receiving a placebo, the Japanese drugmaker reported Thursday.

Kidney function was assessed with a lab test, called eGFR, that measures how well kidneys filter waste from the blood.