Independent evaluation of ibrutinib efficacy 3 years post-initiation of monotherapy in patients with chronic lymphocytic leukemia/small lymphocytic leukemia including deletion 17p disease.

Leukemia, Myelodysplasia, and Transplantation
Session Type and Session Title: 
Oral Abstract Session, Leukemia, Myelodysplasia, and Transplantation
Abstract Number: 
J Clin Oncol 32:5s, 2014 (suppl; abstr 7014)
Susan Mary O'Brien, Richard R. Furman, Steven E. Coutre, Ian Flinn, Jan Andreas Burger, Kristie A. Blum, Jeff Porter Sharman, Jeffrey Alan Jones, William G. Wierda, Weiqiang Zhao, Nyla A. Heerema, Amy J. Johnson, Anh Tran, Cathy Zhou, Elizabeth Bilotti, Danelle Frances James, John C. Byrd; The University of Texas MD Anderson Cancer Center, Houston, TX; Weill Cornell Medical College, New York, NY; Stanford Cancer Center, Stanford University School of Medicine, Stanford, CA; Sarah Cannon Research Institute, Nashville, TN; The Ohio State University, Columbus, OH; Willamette Valley Cancer Institute and Research Center/US Oncology Research, Springfield, OR; Pharmacyclics, Inc., Sunnyvale, CA; Pharmacyclics, Inc, Sunnyvale, CA

Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).

Abstract Disclosures


Background: CLL/SLL is generally very responsive to chemoimmunotherapy. However, relapses occur and resistance develops. In particular, del(17p) is associated with poor outcomes using all currently available treatments. Effective targeted therapies are needed. Ibrutinib, a first-in-class covalent inhibitor of Bruton tyrosine kinase, showed single-agent activity and mild toxicity in treatment-naïve (TN) (Lancet Oncology 2013) and relapsed/refractory (R/R) CLL (NEJM 2013) in the phase 1b/2 study (PCYC-1102). We present independent assessment of efficacy data 3 years following initiation of therapy to confirm and further characterize the durability of response. Methods: Analyses are based upon all patients (pts) treated from first dose on PCYC-1102 until data cut-off on the long-term follow-up study PCYC-1103. Patients received 420 or 840 mg ibrutinib daily. Best overall response rate (ORR) was assessed using iwCLL criteria. Results: Of 132 CLL/SLL (31 TN, 101 R/R) pts evaluated, the median age was 68 years (range, 37–84), with 61% aged ≥ 65 years; 36 (27.3%) pts (2 TN, 34 R/R) had del(17p) and 36 (27.3%) had del(11q). R/R pts including 34 with Del(17p) had a median of 4 (range, 1–12) prior therapies. The updated ORR (by independent review) was 78.0% for all-treated pts (83.9% TN-, 76.2% R/R and 55.9% for those R/R with del(17p)). Additionally, 5 R/R pts, 2 with del(17p), had a best response of PR with lymphocytosis. Median DOR was not reached for all-treated pts, and was 25.0 months (range, 4.8–34.3) in pts with del(17p). Median time on study was 29.4 months (range, 0.7–38.1) for all-treated pts, and 27.3 months (range, 0.9–37.5) for R/R pts with del(17p). More pts receiving prior therapy experienced serious or ≥ Grade 3 adverse events that decreased after 1 year on treatment. No new safety signals were observed in long-term follow-up; 64% of pts remain on treatment with ibrutinib. Conclusions: Single-agent ibrutinib showed durable responses in pts with TN or R/R CLL/SLL including those with del(17p), as independently confirmed with 3 years of follow-up.