June 18 (Reuters) - Zentalis Pharmaceuticals said on Tuesday the U.S. Food and Drug Administration has placed a partial clinical hold on three studies testing its cancer drug, following the death of two trial participants.

Shares of the drug developer slumped about 30% to $5.88 in premarket trading.

The drug, azenosertib, was being tested against solid tumors in an early-stage study and in patients with a type of ovarian and uterine cancer in two mid-stage studies.

The regulator's decision comes after two patients in the ovarian cancer study died due to presumed sepsis, a condition where the body's immune system has an extreme response to an infection, the company said.

Zentalis said it plans to share additional efficacy and safety data for azenosertib from the ovarian cancer trial later this year, adding that it is working with the FDA to resolve the clinical hold. (Reporting by Mariam Sunny in Bengaluru; Editing by Shailesh Kuber)