Josh Nathan-Kazis

A face-off between two experimental treatments for a common kidney disease is sending shares of the biotech Vera Therapeutics on a wild ride.

Vera, based in Brisbane, Calif., unveiled data Monday that showed its drug for a rare and serious kidney condition called immunoglobulin A nephropathy had led to a steep reduction in the amount of protein measured leaking into patients' urine.

That suggested that the drug, called atacicept, was working far better than investors had expected at improving kidney function, and the stock jumped 67.5% in Monday trading.

Then came Friday morning, when Otsuka Pharmaceutical, a Japanese drugmaker, announced the results of a study of its own competing medicine to treat immunoglobulin A nephropathy. Patients on Otsuka's drug, sibeprenlimab, saw what appears to have been an even steeper reduction in protein levels in patients' urine over a similar period of time.

While Otsuka's drug led to a 51.2% reduction, patients in Vera's trial saw a 46% reduction.

It isn't necessarily a huge difference, and the eventual impact for patients is far from clear. But it was enough to burst Vera shareholders' bubbles, and the stock was shedding its Monday gains on Friday.

Vera stock was down 27.9% in Friday trading to $22.09. That's a sharp decline from its Monday close of $31.74, but still 16.6% better than its closing price last Friday of $18.95.

Otsuka stock trades over the counter in the U.S., and was up 4% on Friday.

Immunoglobulin A nephropathy is a chronic condition caused by buildup of a blood protein in the kidneys. It can eventually lead to kidney failure, leaving patients reliant on dialysis or a transplant. Current treatment options are limited. Otuska and Vera are two of a handful of companies working on new antibody treatments that target cells that contribute to the condition.

The hope is that the drugs could keep patients from progressing to end-stage kidney disease.

At least some of the selloff in Vera's shares seem warranted: It seems now, at the very least, that Vera's drug won't be the obvious best-in-class. But analysts warned early Friday that the Otsuka result wasn't different enough from the Vera result to definitively show that it Otsuka's drug works better.

In a note early Friday, Evercore ISI analyst Liisa Bayko wrote that the data suggests that "clinically, these medicines are similar."

Other analysts agreed. "We don't think this is a referendum on the overall efficacy of these drugs," Raymond James analyst Ryan Deschner wrote Friday.

Deschner noted, among other things, that what actually matters is improvement in kidney function, and that the amount of protein in urine is only meant to help indicate whether kidney function is improving. Data from the two trials on a more direct measure of kidney function are not yet available.

Otsuka has applied for Food and Drug Administration approval of sibeprenlimab, and the agency is expected to make its decision in late November. Vera plans to apply for approval for atacicept later this year.

Write to Josh Nathan-Kazis at josh.nathan-kazis@barrons.com

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June 06, 2025 11:02 ET (15:02 GMT)

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