BCL2L1 and Thrombocytopenia: However, their clinical application is hampered by the toxicity associated with multitarget drugs: navitoclax causes thrombocytopenia in patients before an effective dose is reached (NCT00406809) (4, 5) because its target BCL-2 and BCL-XL, especially the latter, play an important role in platelet survival (6, 7).