Otsuka’s kidney disease therapy trial results heat up battle with rival Vera

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By Sriparna Roy and Siddhi Mahatole

(Reuters) -Otsuka’s experimental therapy for a potentially life-threatening kidney disease more than halved severe levels of protein in the urine of patients, intensifying the battle for an effective new treatment with rival Vera Therapeutics.

The Japan-based company said on Friday its therapy, sibeprenlimab, cut proteinuria levels by 51.2% in patients with Immunoglobulin A Nephropathy, also known as Berger’s disease, at nine months in a late-stage trial.

The data comes just days after Vera said its drug, atacicept, reduced protein levels in patients’ urine by 46%, compared with a 7% reduction with a placebo, meeting the main goal of a 428-patient late-stage study.

Shares of the U.S.-based drug developer slid 31% to $20.89.

Analysts, however, said that though data from Otsuka’s sibeprenlimab might look superior, it was unlikely that doctors would interpret it that way.

The difference between the two datasets is not too clinically diverse to affect demand for Vera’s drug, said Jefferies analyst Farzin Haque.

Berger’s disease causes abnormal protein buildup in the kidneys and could eventually lead to the organ’s failure. Analysts have estimated the U.S. market for its treatments could be worth as much as $10 billion.

Otsuka has already applied for the FDA’s accelerated approval for its therapy to treat the disease. However, its sales would largely depend on whether the treatment can improve kidney function, analysts said.

Even if the drug gains accelerated approval, Otsuka said it plans to study whether it can preserve the organ’s ability to filter toxins from blood, measured as the glomerular filtration rate (eGFR).

“The magnitude of the protein reduction should translate into eGFR preservation down the line, because ultimately that’s what patients are going to be asking for,” Dana Rizk, the trial’s investigator and a professor of medicine at the University of Alabama in Birmingham, told Reuters.

The study is expected to be completed in early 2026.

(Reporting by Sriparna Roy and Siddhi Mahatole in Bengaluru; Editing by Shinjini Ganguli)