Overview Navitoclax (ABT-263) is a small-molecule BH3 mimetic — a drug that mimics the BH3 (Bcl-2 homology domain 3) domain of pro-apoptotic proteins to inhibit anti-apoptotic BCL-2 family members (BCL-2, BCL-XL, BCL-W). It was developed by AbbVie as an oncology agent targeting BCL-2-dependent…