Sept 30 (Reuters) - Kezar Life Sciences ( KZR ) said on

Monday it has paused a trial of its experimental drug for lupus

to review safety data after four patients died in the mid-stage

study.

The San Francisco-based company said it had informed the

U.S. Food and Drug Administration and European regulators of the

decision to pause enrollment and dosing in the trial.

An independent study committee had recommended the pause

after reviewing safety data, following the deaths of patients

enrolled in trials in the Philippines and Argentina.

Review of the data by the committee showed three of the

fatalities showed a common pattern of symptoms and the deaths

happened close to the time of dosing, while a non-fatal adverse

event showed a similar proximity to dosing, the company said.

Kezar was testing the treatment, zetomipzomib, in patients

with active lupus nephritis, a type of kidney disease caused by

lupus - where the body's immune system attacks its own cells and

organs.

To date, 84 patients have been enrolled in the mid-stage

trial, according to Kezar.

The company said it has not observed any instances of death

or serious infections in prior clinical studies of zetomipzomib.

Another mid-stage trail testing zetomipzomib in patients

with autoimmune hepatitis, remains active with no serious

adverse events observed to date, the drug developer said.