Outcomes of Anticoagulant (ac) or Antiplatelet (ap) Use in Patients (pts) with Chronic Lymphocytic Leukemia (cll) or Indolent Non-Hodgkin'S Lymphoma (inhl) in Idelalisib (idela) Trials

8563 Background: IDELA, a selective oral PI3Kδ inhibitor, is approved for use in relapsed CLL (in combination with rituximab [R]) and iNHL (as monotherapy). Both diseases occur mainly in the elderly, who have comorbidities that increase thrombotic risk. This post hoc analysis characterized the use and outcomes of AC/AP therapy, which was allowed in IDELA registrational clinical trials. Methods: In the phase 3 Study 312-116 (NCT01539512), frail pts with relapsed CLL (including those with any degree of thrombocytopenia) were randomized to receive a combination of continuous IDELA 150 mg BID or placebo (PBO) with 8 R doses. In the phase 2 Study 101-09 (NCT01282424), pts with refractory iNHL received IDELA 150 mg BID until disease progression or unacceptable toxicity. Grade 1, 2, and ≥3 bleeding events were analyzed using MedDRA preferred terms and CTCAE. Results: The 2 trials included 343 pts. In the CLL study, 18 pts (16%) on IDELA + R and 31 (29%) on PBO + R had grade ≥3 thrombocytopenia at baseline. Concomitant AC/AP use was frequent (45% in each study); the most common were aspirin, enoxaparin, and warfarin. AC/AP use was more frequent in pts treated with IDELA + R vs PBO + R. The incidence of bleeding events was similar with IDELA, IDELA + R, and PBO + R. Grade ≥3 bleeding events occurred in 1 IDELA + R, 1 PBO + R, and 3 IDELA pts. Conclusions: AC/AP use involved 45% of the IDELA registrational trial population. Overall, rates of bleeding events were moderate and similar with IDELA + R vs IDELA + PBO; grade ≥3 events were uncommon. There was no specific trend with regard to AC/AP and bleeding events in the 2 arms of the CLL study. Clinical trial information: NCT01282424 and NCT01539512. n (%) CLL iNHL IDELA + R n=110 PBO + R n=108 IDELA Monotherapy n=125 Pts receiving AC/AP 60 (55) 38 (35) 56 (45) Aspirin 42 (38) 21 (19) 30 (24) Enoxaparin 11 (10) 6 (6) 19 (15) Warfarin 8 (7) 9 (8) 11 (9) Pts with ≥1 bleeding event (any grade) Overall 15 (14) 20 (19) 17 (14) Grade 1/2 14 (13) 19 (18) 14 (11) Pts on AC/AP n=60 n=38 n=56 Event at any time 10 (17) 6 (16) 14 (25) Event on AC/AP 7 (12) 5 (13) 8 (14) AC at any time 9 4 13 AP at any time 5 3 6 Patients not on AC/AP n=50 n=70 n=69 Event at any time 5 (10) 14 (20) 3 (4)