At the 2026 American Society of Clinical Oncology annual meeting, multiple companies presented data for their drugs targeting WEE1, a checkpoint for the transition from G2 into mitosis. Aprea Therapeutics Inc. presented phase 1 data for its WEE1 inhibitor APR-1051 in patients with advanced solid tumors showing two patients with endometrial cancers achieved partial responses in the dose-escalation study. Likewise, Zentalis Pharmaceuticals Inc. had tantalizing early results from a phase Ib study showing azenosertib plus paclitaxel in patients with platinum-resistant ovarian cancer produced an overall response rate of 39% with a median progression-free survival of 7.3 months.