05:20 PM EDT, 10/13/2025 (MT Newswires) -- Geron ( GERN ) said Chief Operating Officer Andrew Grethlein and Chief Commercial Officer Jim Ziegler are departing, effective Wednesday.

Ahmed ElNawawi will become CCO on Oct. 20, and Shanthakumar Tyavanagimatt joins as chief technical officer, the company said Monday in a statement.

Grethlein moves to a consulting role. A successor for the COO position has not been named.

Dawn Schottlandt joins as senior vice president of investor relations on Oct. 20, and Bryan Ridgell was appointed chief of staff, effective Wednesday.