Geron Corporation Announces Executive Leadership Transitions and Appointments

On October 13, 2025, Geron Corporation announced several executive leadership transitions and appointments to align its structure with commercial and strategic priorities9 4 11.

Andrew Grethlein, Ph.D., Executive Vice President and Chief Operating Officer, will depart the company on October 15, 2025, transitioning to a consulting role9 10.

Jim Ziegler, Executive Vice President and Chief Commercial Officer, is also leaving Geron on October 15, 20259 10.

Ahmed ElNawawi ('Nawawi') has been appointed Executive Vice President, Chief Commercial Officer, effective October 20, 2025; he will lead Geron's commercial organization and advance strategic growth, including maximizing RYTELO® (imetelstat) potential9 7.

Harout Semerjian has been named President and Chief Executive Officer, bringing over 30 years of commercial and leadership experience in hematology and oncology from companies such as Novartis and Ipsen6 10.

Additional key appointments include Shanthakumar Tyavanagimatt (Senior Vice President, Chief Technical Officer), Dawn Schottlandt (Senior Vice President, Investor Relations and Corporate Affairs), and Bryan Ridgell (Senior Vice President, Portfolio and Project Management and Chief of Staff)9.

The announced changes are intended to strengthen Geron's commercial operations, support ongoing product development, and position the company for future portfolio expansion and long-term value creation9 12.