Left atrial abnormality (LAA) as a predictor of ibrutinib-associated atrial fibrillation in patients with chronic lymphocytic leukemia.

Results from several recent studies in chronic lymphocytic leukemia (CLL) have demonstrated an association between ibrutinib exposure and the development of atrial fibrillation, estimated incidence of 11% with long-term follow up. This is a common cause of ibrutinib discontinuation. Risk factors for atrial fibrillation include advanced age, hypertension (HTN), mitral valve disease (MVD), left atrial remodeling, coronary artery disease (CAD) and risk factors for cardiovascular dysfunction We conducted a retrospective case control study using the presence of left atrial abnormality identified on pre-ibrutinib EKGs, defined as either (1) Lead II-bifed p wave, with 40 mcsec between peaks for ≥ 2.5 mm wide ≥ 100 msec in duration, (2) Lead V1-biphasic P wave with terminal portion ≥ 40 msec in duration or terminal portion ≥ 1 mm deep or (3) PR interval ≥ 200 msec (intra-atrial conduction delay) as a predictor for development of atrial fibrillation. 183 consecutively CLL patients treated with ibrutinib were identified. 44 patients met inclusion criteria (20 cases, 24 controls). 20 (11.3%) of patients developed atrial fibrillation. Left atrial enlargement was identified as a significant predictor of development of atrial fibrillation (OR 9.1, 95% CI 2.2-37.3, p=0.02). Age, baseline HTN, CAD, diabetes, age and sex were not significant predictors. Area under the ROC curve for the model was estimated to be 75%. LAA identified by EKG is a moderately specific and sensitive finding that can identify patients at increased risk for this toxicity.

Outcomes of CLL patients treated with sequential kinase inhibitor therapy: a real world experience.

B-cell receptor kinase inhibitor (KI) therapy represents a paradigm shift in chronic lymphocytic leukemia (CLL) management, but data on practice patterns after KI discontinuation and optimal sequencing are limited. We conducted a multicenter, retrospective, comprehensive analysis on 178 patients with CLL (ibrutinib = 143; idelalisib = 35) who discontinued KI therapy. We examined responses, toxicity, post-KI therapies, and overall survival (OS). Patients had a median of 3 prior therapies (range 0-11); del17p (34%), p53 mutation (27%), del11q (33%), and complex karyotype (29%). Overall response rate (ORR) to first KI was 62% (complete response 14%). The most common reasons for KI discontinuation were toxicity (51%), CLL progression (29%), and Richter transformation (RT) (8%). Median progression-free survival (PFS) and OS from KI initiation were 10.5 and 29 months, respectively. Notably, initial KI choice did not impact PFS or OS; however, RT portended significantly inferior OS (P = .0007). One hundred fourteen patients received subsequent salvage therapy following KI discontinuation with an ORR to subsequent KI at 50% and a median PFS of 11.9 months. Median PFS in KI-intolerant patients treated with an alternate KI was not reached vs 7 months for patients with CLL progression. In summary, these data demonstrate that toxicity was the most common reason for KI discontinuation, that patients who discontinue KI due to toxicity can respond to an alternate KI, and that these responses may be durable. This trial was registered at www.clinicaltrials.gov as #NCT02717611 and #NCT02742090.