Introduction: Ibrutinib (Ibr) is a kinase inhibitor (KI) indicated for treating CLL. Clinical trials that led to its approval showed that its unique side effects differ from traditional chemotherapy toxicities. We previously reported (Mato et al, ASH 2015) that intolerance was the most common reason for discontinuation of Ibr in 123 patients treated in a real world setting. Whether reasons for discontinuation reported in clinical trials mirror those encountered in the real world is unknown and has not been studied. Therefore, we conducted a retrospective analysis of 621 CLL patients treated with Ibr either on clinical studies or commercially. We aimed to compare the type and frequency of toxicities reported in either setting, assess discontinuation rates, and evaluate outcomes. Patients and Methods: This multicenter, retrospective analysis included Ibr-treated CLL patients at 9 US cancer centers or the Connect® CLL Registry. We examined demographics, dosing, discontinuation rates and reasons, toxicities, and outcomes. The primary endpoint was progression-free survival (PFS) (time from KI treatment to progression, death or last f/u) as determined by the Kaplan Meier method. Comparisons of outcomes data were made using the log rank (LR) test. All other comparisons were descriptive. Results: 621 patients treated with Ibr were identified. Table 1 includes available baseline characteristics stratified by line of therapy. A total of 546 (88%) patients were treated with commercial drug. Clinical trial patients were younger (median age 57 vs. 61 years), had a longer time from diagnosis to Ibr (median 85 vs. 72 months) and were more consistently initiated at 420 mg daily (100% vs. 89%). With a median f/u of 14.5 months, the Ibr discontinuation rate was estimated to be 42% (median time to Ibr discontinuation was 7 months). Reasons for discontinuation are listed in table 2. Notably, Ibr toxicity was the most common reason for discontinuation in all settings. Ibr starting dose (420 mg daily vs. < 420 mg daily) did not impact the proportion of patients who discontinued Ibr due to toxicity (51% vs. 50%). In relapsed CLL, the 5 most common Ibr-related toxicities as a reason for discontinuation included: atrial fibrillation (12.3%), infection (10.7%), pneumonitis (9.9%), bleeding (9%), and diarrhea (6.6%). In front line CLL, the 3 most common Ibr-related toxicities as a reason for discontinuation included arthralgia (41.6%), atrial fibrillation (25%), and rash (16.7%). Median times to discontinuation by toxicity were as follows: bleeding (8 months), diarrhea (7.5 months), atrial fibrillation (7 months), infection (6 months), arthralgia (5 months), pneumonitis (4.5 months), and rash (3.5 months). Median PFS and OS for the entire cohort were 35 months and not reached (median f/u 17 months) respectively. Figure 1 describes PFS for Ibr treated patients stratified by line of therapy (A), reason for discontinuation (B), clinical trial participation (C) and depth of response (D). In a multivariable model, complex karyotype was validated as an independent predictor of PFS (HR 1.6, CI 1.1-2.5 p=.04) but not OS (HR 1.6, CI .9-3.1 p=.1). Conclusions: In the largest reported series on Ibr-treated CLL patients, we show that 40% of patients have discontinued Ibr during this observation period. Intolerance as opposed to CLL progression or transformation was the most common reason for discontinuation. As compared to previous reports from clinical trials, the discontinuation rate appears to be higher suggesting (1) a learning curve in terms of toxicity management, (2) a higher incidence of toxicity in clinical practice, (3) or a lower threshold for discontinuation given alternative choices. Outcomes remain excellent and were not impacted by line of therapy and whether patients were treated on studies or commercially. These data strongly argue to find strategies to minimize Ibr intolerance so that efficacy can be further maximized. Figure 1 Figure 1. Disclosures Mato: Abbvie, Acerta Pharma, Gilead Sciences, ProNAi, TG Therapeutics, Theradex: Research Funding; Abbvie, Gilead Sciences, Pharmacyclics, TG Therapeutics: Consultancy. Lamanna:Acerta: Research Funding; TGR Therapeutics: Research Funding; Janssen: Honoraria; Pharmacyclics: Honoraria, Research Funding; Roche-Genentech: Honoraria, Research Funding; Celgene: Honoraria; AbbVie: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Infinity: Research Funding; Acerta: Research Funding; TGR Therapeutics: Research Funding. Ujjani:Gilead: Consultancy; Abbvie: Consultancy; Genentech: Consultancy; Pharmacyclics: Consultancy. Brander:TG Therapeutics: Research Funding; Gilead: Honoraria. Howlett:Sandoz: Honoraria; Teva: Speakers Bureau; Amgen: Honoraria; Pfizer: Honoraria; Eisai: Honoraria. Skarbnik:Gilead Sciences: Speakers Bureau; Seattle Genetics: Speakers Bureau; Genentech: Speakers Bureau; Abbvie: Consultancy; Pharmacyclics: Consultancy. Cheson:Acerta: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kiselev:Celgene: Employment, Equity Ownership. Nasta:Millennium Pharmaceuticals: Research Funding. Schuster:Janssen Research & Development: Research Funding; Hoffman-LaRoche: Research Funding; Gilead: Research Funding; Nordic Nanovector: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Research Funding; Merck: Research Funding. Porter:Novartis: Patents & Royalties, Research Funding; Genentech: Employment. Nabhan:Seattle Genetics: Research Funding; Cardinal Health: Consultancy; Infinity: Consultancy; Abbvie: Consultancy; Genentech: Consultancy, Research Funding; Celgene Corporation: Consultancy, Research Funding; Astellas: Research Funding. Barr:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Research Funding; AbbVie: Consultancy.
Introduction: Ibrutinib (Ibr), idelalisib (Ide), andvenetoclax (Ven), are all now approved for treating CLL patients in the US. However, in the absence of head-to-head comparator trials, there is limited guidance as to the optimal sequence of these therapies and to the best choice upon failure of first selected agent. To address these gaps in current literature, 9 large US cancer centers and the Connect CLL Registry collaborated to capture the experience of 683 CLLpts treated with kinase inhibitors (KIs) - focusing on optimal sequencing and patterns of failure. Patients and Methods: We conducted a multicenter, retrospective analysis of CLLpts treated withIbr-, Ide- orVen-based therapy. We examined demographics, discontinuation rates, reasons for discontinuation, overall response rates (ORR), survival, and post kinase inhibitor (KI) salvage strategies. Primary endpoint was progression-free survival (PFS) (time from KI treatment to progression, death, or last follow-up) as determined by the Kaplan Meier (KM) method. Comparisons were made using the log rank (LR) test and COX regression analyses. Results: A total of 683 pts treated with KI therapy (Ibr=621/Ide=62) were identified (Table 1). Baseline characteristics were similar in theIbr and Ide-based groups. ORR toIbr as first KI was 69% [complete response (CR) 11%, partial response (PR) 45%, and PR-L 13%] and Ide was 81% (CR 5%, PR 71%,PR-L 5%). With a median follow-up from start of first KI of 17 months (range 1-60), median PFS and OS for the entire cohort from first KI was 35 months (216 events) and not reached respectively (107 events). Interestingly,pts treated withIbr (vs. Ide) as first KI had a significantly better PFS in all settings; front-line (figure a, HR 2.8, CI 1.3-6.3 p=.01), relapsed-refractory (figure b, HR 2.8, CI 1.9-4.1 p<.001), clinical trials (HR 3.3, CI 1.8-5.9 p<.001), commercial use (HR 2.5, CI 1.5-4.0 p<.001), del17p (HR 2.0, CI 1.2-3.4 p=.008), or complex karyotype (HR 2.5, CI 1.2-5.2 p=.02). Moreover, at the time of initial KI failure, the use of either an alternate KI orVen was associated with superior PFS as compared tochemoimmunotherapy (CIT) combinations (figure c). When treated with an alternate KI (Ibr followed by Ide or Ide followed byIbr),pts intolerant of a KI therapy due to toxicity had a superior PFS compared with those taken off a KI therapy due to CLL progression (p=0.03, LR test). Furthermore,Ibr-failurepts had a marginally better PFS if treated withVen (ORR 79%) vs. Ide (ORR 46%) (figure d, HR .6, CI.3-1.0 p=.06). Conclusions: In the largest experience of novel agents published to date in CLL,Ibr appears superior to Ide in all settings as first choice KI. Further, in the setting of KI failure, an alternate KI orVen therapy appear superior to CIT combinations. Alternate KI appear particularly effective in the setting of intolerance to a prior KI. The use ofVen uponIbr failure might be superior to the use of Ide. These data provide guidance for sequencing of novel agents and support the need for trials directly comparing novel agents and sequencing strategies in CLL. Table 1 Table 1. Figure Figure. Disclosures Mato: Abbvie, Gilead Sciences, Pharmacyclics, TG Therapeutics: Consultancy; Abbvie, Acerta Pharma, Gilead Sciences, ProNAi, TG Therapeutics, Theradex: Research Funding. Lamanna:Roche-Genentech: Honoraria, Research Funding; Celgene: Honoraria; Janssen: Honoraria; Pharmacyclics: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Infinity: Research Funding; Acerta: Research Funding; TGR Therapeutics: Research Funding. Barr:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Research Funding; AbbVie: Consultancy. Ujjani:Genentech: Consultancy; Abbvie: Consultancy; Gilead: Consultancy; Pharmacyclics: Consultancy. Brander:Gilead: Honoraria; TG Therapeutics: Research Funding. Cheson:Acerta: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kiselev:Celgene: Employment, Equity Ownership. Svoboda:Seattle Genetics: Research Funding; Pharmacyclics: Research Funding; Celgene: Research Funding. Schuster:Genentech: Consultancy, Honoraria; Gilead: Research Funding; Pharmacyclics: Consultancy, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Hoffman-LaRoche: Research Funding; Nordic Nanovector: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Janssen Research & Development: Research Funding. Nabhan:Celgene Corporation: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Abbvie: Consultancy; Infinity: Consultancy; Cardinal Health: Consultancy; Seattle Genetics: Research Funding; Astellas: Research Funding.
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