Navitoclax, a BH3 mimetic that inhibits both BCL2 and BCL-XL, was the first potent BCL2 inhibitor to enter clinical trials; however, profound thrombocytopenia proved to be the dose-limiting toxicity due to the critical role of BCL-XL in platelet survival [1]. Here, BCL2L1 is linked to Thrombocytopenia.