Real-World Characteristics and Outcome of Patients Treated With Single-Agent Ibrutinib for Chronic Lymphocytic Leukemia in Spain (IBRORS-LLC Study)

Original Article Real-World Characteristics and Outcome of Patients Treated With Single-Agent Ibrutinib for Chronic Lymphocytic Leukemia in Spain (IBRORS-LLC Study) Pau Abrisqueta, 1 Javier Loscertales, 2 Maria José Terol, 3 Ángel Ramírez Payer, 4 Macarena Ortiz, 5 Inmaculada Pérez, 6 Carolina Cuellar-García, 7 Margarita Fernández de la Mata, 8 Alicia Rodríguez, 9 Ana Lario, 10 Julio Delgado, 11 Ana Godoy, 12 José M ªArguiñano Pérez, 13 M ªJosé Berruezo, 14 Ana Oliveira, 15 José-Ángel Hernández-Rivas, 16 Maria Dolores García Malo, 17 Ángeles Medina, 18 Paloma García Martin, 19 Santiago Osorio, 20 Patricia Baltasar, 21 Miguel Fernández-Zarzoso, 22 Fernando Marco, 23 M ªJesús Vidal Manceñido, 24 Alicia Smucler Simonovich, 25 Montserrat López Rubio, 26 Isidro Jarque, 27 Alexia Suarez, 28 Rubén Fernández Álvarez, 29 Aima Lancharro Anchel, 30 Eduardo Ríos, 31 María del Carmen Losada Castillo, 32 Ernesto Pérez Persona, 33 Ricardo García Muñoz, 34 Rafael Ramos, 35 Lucrecia Yáñez, 36 José Luis Bello, 37 Cristina Loriente, 38 Daniel Acha, 38 Miguel Villanueva 38 Abbreviations: AE, adverse event; BR, bendamustine plus rituximab; Clb, chlorambucil; CLL, chronic lymphocytic leukemia; CI, confidence interval; CIT, chemoimmunotherapy; CR, complete response; CT, computed tomography; ECOG, Eastern Cooperative Oncology Group; FCR, fludarabine, cyclophosphamide, and rituximab; HR, hazard ratio; IgA, immunoglobulin A; IGHV, immunoglobulin heavy chain; NCI-CTCAE, National Cancer Institute Common Terminology Criteria for adverse events; NR, not reached; OR, Odds ratio; ORR, overall response rate; OS, overall survival; PD, progressive disease; PFS, progression-free survival; PR, partial response; PR-L, partial remission with lymphocytosis; R/R, relapsed/refractory; TN, treatment naïve. 1 Hospital Universitario Vall d ´ Hebron, Barcelona, Spain 2 Hospital Universitario La Princesa, IIS-IP, Madrid, Spain 3 Hospital Clínico Universitario de Valencia, Valencia, Spain 4 Hospital Universitario Central de Asturias, Oviedo, Spain 5 Hospital Regional Universitario de Málaga, Malaga, Spain 6 Hospital Virgen de la Victoria, Málaga, Spain 7 Hospital de la Santa Creu i Sant Pau, Barcelona, Spain 8 Hospital Universitario Reina Sofía, Córdoba, Spain 9 Hospital Universitario Virgen Macarena, Sevilla, Spain 10 Hospital Universitario Ramón y Cajal, Madrid, Spain 11 Hospital Clinic i Provincial, Barcelona, Spain 12 Hospital Universitario Miguel Servet, Zaragoza, Spain 13 Complejo Hospitalario de Navarra, Pamplona, Spain 14 Hospital Universitario de Jerez, Cádiz, Spain 15 ICO L’Hospitalet, L’Hospitalet de Llobregat, Spain 16 Hospital Universitario Infanta Leonor, Madrid, Spain 17 Hospital General Universitario Morales Meseguer, Murcia, Spain 18 Hospital Costa del Sol, Málaga, Spain 19 Hospital Universitario Virgen de las Nieves, Granada, Spain 20 Hospital General Universitario Gregorio Marañón, Madrid, Spain 21 Hospital Universitario La Paz, Madrid, Spain 22 Hospital Universitario Dr. Peset, Valencia, Spain 23 Hospital Universitario de Basurto, Bilbo, Bizkaia, Spain 24 Hospital Universitario de León, León, Spain 25 Hospital Universitario El Bierzo, Ponferrada, León, Spain 26 Hospital Universitario Principe de Asturias, Alcalá De Henares, Madrid, Spain 27 Hospital Universitario La Fe, Valencia, Spain 28 Hospital Universitario de Gran Canaria Doctor Negrín, Las Palmas, Spain 29 Hospital de Cabueñes, Gijón, Spain 30 Hospital General Universitario de Castellón, Castellón, Spain 31 Hospital Universitario Virgen de Valme, Sevilla, Spain 32 Hospital Universitario Insular de Gran Canarias, Las Palmas de Gran Canaria, Las Palmas, Spain 33 Hospital Txagorritxu, Vitoria-Gasteiz, Spain 34 Hospital San Pedro, Logroño, Spain 35 Hospital Universitario de Badajoz, Badajoz, Spain 36 Hospital Universitario Marqués de Valdecilla, Santander, Spain 37 Hospital Clínico Universitario de Santiago-CHUS, Santiago de Compostela, A Coruña, Spain 38 Medical Department-Hematology Janssen-Cilag, S.A., Madrid, Spain Submitted: May 21, 2021; Revised: Jul 16, 2021; Accepted: Jul 19, 2021; Epub: 3 August 2021 Address for correspondence: Pau Abrisqueta, MD, PhD. Department of Hematology, Hospital Universitario Vall d ´ Hebron, Passeig de la Vall d’Hebron, 119-129, 08035 Barcelona, Spain. E-mail contact: [email protected] 2152-2650/$ - see front matter © 2021 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ) https://doi.org/10.1016/j.clml.2021.07.022 Clinical Lymphoma, Myeloma and Leukemia December 2021 e985 Real-World-Evidence of Ibrutinib for CLL treatment Abstract Ibrutinib demonstrated robust efficacy, regardless of high-risk features, in previously untreated or relapsed/refractory chronic lymphocytic leukemia (CLL). The IBRORS-CLL study supports the effectiveness and the manageable safety profile of single-agent ibrutinib, which was not adversely affected by high-risk characteristics in real-world CLL patients in Spain. We also found a high molecular testing rate of del(17p)/TP53 mutation and IGHV mutation status. Background: Ibrutinib demonstrated remarkable efficacy and favorable tolerability in patients with untreated or relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL), including those with high-risk genetic alterations. The IBRORS-CLL study assessed the characteristics, clinical management and outcome of CLL patients receiving ibrutinib in routine clinical practice in Spain.Patients: Observational, retrospective, multicenter study in CLL patients who started single-agent ibrutinib as first-line treatment or at first or second relapse between January 2016 and January 2019. Results: A total of 269 patients were included (median age: 70.9 years; cardiovascular comorbidity: 55.4%, including hypertension [47.6%] and atrial fibrillation [AF] [7.1%]). Overall, 96.7% and 69% of patients underwent molecular testing for del(17p)/TP53 mutation and IGHV mutation status. High-risk genetic features included unmutated IGHV (79%) and del(17p)/TP53 mutation (first-line: 66.3%; second-line: 23.1%). Overall, 84 (31.2%) patients received ibrutinib as first-line treatment, and it was used as second- and third-line therapy in 121 (45.0%) and 64 (23.8%) patients. The median progression-free survival and overall survival were not reached irrespective of del(17p)/TP53, or unmutated IGHV. Common grade ≥3 adverse events were infections (12.2%) and bleeding (3%). Grade ≥3 AF occurred in 1. 5 % of patients. Conclusion: This real-wor ld study shows that single-agent ibr utinib is an effective therapy for CLL, regardless of age and high-risk molecular features, consistent with clinical trials. Additionally, single-agent ibrutinib was well tolerated, with a low rate of cardiovascular events. This study also emphasized a high molecular testing rate of del(17p)/TP53 mutation and IGHV mutation status in clinical practice according to guideline recommendations. Clinical Lymphoma, Myeloma and Leukemia, Vol. 21, No. 12, e985–e999 © 2021 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ) Keywords: Chronic lymphocytic leukemia (CLL), Effectiveness, First-line, Ibrutinib, Real-world, Relapsed/refractory (R/R) Introduction Chronic lymphocytic leukemia (CLL) is characterized by a marked immune dysfunction 1 and a heterogeneous clinical outcome mainly determined by the patient ´ s clinical features, cytogenetic alterations and gene mutations. 2 , 3 Deletions in chromosome 17p [del(17p)] and mutation in TP53 gene, deletion of 11q [del(11q)], and unmutated immunoglobulin heavy chain variable (IGHV) region gene status is associated with poor response and outcome to chemoimmunotherapy (CIT). 4-9 Testing of these alterations is therefore of paramount importance for guiding treatment decisions in routine clinical practice in CLL. 10-12 Additional analysis as complex karyotype (i.e., ≥3 chromosomal abnormalities), that have an adverse prognostic significance, are still considered investigational. 10 , 11 , 13 Ibrutinib is a first-in-class, oral once-daily, covalent inhibitor of Bruton ´ s tyrosine kinase (BTK), which has demonstrated higher efficacy and favorable tolerability profile compared to the most effective CIT regimens in both relapsed/refractory (R/R) 14 , 15 and treatment-naïve (TN) 16-19 patients. Therefore, the efficacy and safety seen in clinical trials support the use of ibrutinib for all CLL patient profiles which require treatment. The benefit demonstrated with ibrutinib in clinical trials has also been observed in the real-world setting. 20-31 However, most realworld evidence came from studies in R/R CLL, 20 , 25-27 , 30 , 31 including reports where ibrutinib was used in compassionate use programs 24 , 27 , 30 , 31 and from single-site experience. 22 , 26 Additionally, realworld data from different healthcare systems across countries may be heterogeneous due to divergences in clinical practice, and nationwide experiences are of particular interest. This real-world study aimed to explore the clinical, genetic, and molecular characteristics of CLL patients receiving single-agent ibrutinib in earlier lines of therapy in Spain. We also assessed the effectiveness of ibrutinib in terms of response and clinical outcome and the safety and tolerability profile of this agent when used under routine clinical practice conditions. Patients and Methods Study Design and Patients The IBRORS-LLC was a multicenter, retrospective, observational study to explore the characteristics and clinical outcome of patients treated with single-agent ibrutinib in earlier therapy lines in the realworld setting in Spain. The study included patients aged ≥18 years diagnosed with CLL requiring treatment who started single-agent ibrutinib as first-line treatment or at first or second relapse from January 2016 (start of ibrutinib commercialization in Spain) to January 2019 (at least 6 months before study entry) under routine clinical practice conditions. Patients were excluded if they had participated in an interventional study while receiving ibrutinib. The primary study endpoint was the demographic, clinical, genetic and molecular characterization of patients at diagnosis and ibrutinib treatment initiation. For this purpose, a retrospective chart review was performed to collect data on comorbidities, concomitant therapies, disease characteristics such as the stage of e986 Clinical Lymphoma, Myeloma and Leukemia December 2021 Pau Abrisqueta et al the disease, common chromosomal aberrations, namely del(13q), trisomy 12, del(11q), and del(17p), and molecular alterations including del(17p)/TP53 mutation, IGHV mutation status and complex kar yotype. Secondar y endpoints included overall response rate (ORR), OS, PFS, time to response, time to subsequent CLL therapy, and immune reconstitution based on immunoglobulin A (IgA) levels and CD4/CD8 ratio. Single-agent ibrutinib safety profile and management (dose reduction and interruption, discontinuation), and post-ibrutinib therapy for CLL were also assessed. Independent ethics committees approved the study, which was carried out in accordance with the Declaration of Helsinki and Good Clinical Practice Guidelines and applicable regulatory requirements. Written informed consent was obtained from all patients before their inclusion in the study, except for those deceased at the time of study initiation, in which case the requirement for informed consent was waived for retrospective collection of data from medical charts. Centralized monitoring (remote evaluation of the study data) was carried out to ensure study data quality. Statistical Analysis A descriptive statistical analysis was performed to describe the demographic, clinical, genetic and molecular characteristics of patients receiving single-agent ibrutinib. The analysis focused on the overall population (ibrutinib administered at any treatment line) and in the first- and second-line setting. Measures of central tendency and dispersion (mean ±standard deviation, median and interquartile range [IQR]) were used to describe quantitative variables and counts and percentages were applied to report qualitative variables. Comparisons between categorical variables were performed using the Chi-squared or the Fischer exact test, and continuous variables were compared using the Mann-Whitney U test or the Kruskal-Wallis test. The ORR was defined as the proportion of patients achieving a complete response (CR), nonconfirmed CR, partial response (PR), and partial remission with lymphocytosis (PR-L). The best response to treatment was defined based on the clinical description and biochemistry 10 as bone marrow biopsy and computed tomography (CT) scan are not mandatory in clinical practice to evaluate response. OS was calculated from ibrutinib treatment initiation to death from any cause. PFS was calculated from ibrutinib treatment initiation to disease progression or death from any cause. Time to subsequent CLL therapy was measured from treatment initiation to the administration of a new CLL therapy or death, whichever was first. Time-to-event variables were estimated by using the Kaplan- Meier method, and groups were compared with the Log-rank test. Post-hoc analyses were conducted to assess ORR and the outcome in terms of PFS and OS according to age ( ≤65 years vs. > 65 years) and cardiovascular comorbidities (hypertension, diabetes mellitus [DM], atrial fibrillation [AF], other arrhythmias, and/or stroke). Additionally, the impact of del(11q), del(17p)/TP53 mutation, IGHV mutational status, and complex karyotype on the response, PFS and OS, was also assessed. A multivariate COX regression analysis of potential factors associated with PFS was carried out. Variables with statistical significance P < .2 in the univariate analysis were included in a multivariate model using a stepwise selection method. Hazard ratio (HR) and 95% confidence intervals (CI) were calculated. The covariates assessed as potential independent factors for PFS in the univariate analysis included age, disease stage (based on Rai and Binet), β2- microglobulin level, and cytogenetic and molecular alterations at diagnosis (trisomy 12, del(11q), del(17p)/TP53 mutation, IGHV mutation status, and complex karyotype). Adverse events (AEs) occurring during single-agent ibrutinib treatment (regardless of attribution) were described and graded according to the National Cancer Institute Common Terminology Criteria for AEs (NCI-CTCAE) version 4.0. Statistical analyses were performed using the Statistical Package for the Social Sciences version 18.0, with a significance level of 0.05. Results Patient Characteristics Between December 2018 and August 2019, 286 patients were enrolled in the study at 37 Spanish hospitals. Seventeen patients were excluded due to non-compliance with eligibility criteria. Thus, 269 patients were included in the study and evaluable for effectiveness and safety analyses. Overall, 84 (31.2%) patients received single-agent ibrutinib as first-line treatment for CLL, and it was used as second- and thirdline therapy in 121 (45.0%) patients and 64 (23.8%) patients, respectively. Table 1 shows the baseline demographic, clinical, and genetic characteristics of the overall population and according to the line in which ibrutinib was received. The median age of patients at treatment initiation was 70.9 years, with 46.8% of patients being older than 65 years. Most patients had an ECOG performance status of 0 to 1 (94.9%). Overall, 50.8% of patients presented Rai Binet stage B/C. The most common comorbidity before ibrutinib treatment initiation was cardiovascular disease, most commonly arterial hypertension (47.6%), dyslipidemia (26.8%), DM (19%), and AF (7.1%). Accordingly, concomitant treatment mainly included antihypertensives (41.6%), antiplatelet (11.5%), and anticoagulant therapy (7.8%). Overall, 10 (3.7%) and 6 (2.2%) patients were receiving vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs) (apixaban), respectively, at ibrutinib treatment initiation ( Table 1 ). Del(11q) and del(13q) were detected in 17.7% (45/254) and in 38.1% (98/257) of patients, respectively. Trisomy 12 was reported in 16.5% (43/261) of patients. The presence of del(17p)/TP53 mutation was evaluated in most patients (96.7%; 260/269), and IGHV mutation status was assessed in 69% (186/269) of patients at diagnosis. Del(17p)/TP53 mutation was detected in 66.3% (55/83) and 23.1% (27/117) of patients who received ibrutinib in the first- and the second-line setting, respectively. Unmutated IGHV was reported in 79% (147/186) of patients. Complex karyotype was present in 7.9% (18/227) of patients. ( Table 1 ). Preibrutinib Therapy for CLL The CLL therapies used as first- and second-line treatment before ibrutinib treatment initiation are described in Table 2 . A total of 185 patients had previously received CLL treatment, with 121 and 64 patients receiving one and two previous lines of therapy, respectively. Overall, 144 (77.8%) patients receiving ibrutinib in the R/R setting Clinical Lymphoma, Myeloma and Leukemia December 2021 e987 Real-World-Evidence of Ibrutinib for CLL treatment Table 1 Demographic, Clinical, and Genetic Characteristics of Patients Receiving Single-Agent Ibrutinib in the Overall Population and in the First- and the Second-Line Setting Variable First Line Second Line Overall Population (N = 84) (N = 121) (N = 269) Median age (range), years a 71.3 (63-77) 70.1 (62.2-78.5) 70.9 (63.1-77.4) > 65 y, n (%) 50 (59.5) 53 (43.8) 126 (46.8) Gender, male, n (%) 52 (61.9) 84 (69.4) 178 (66.2) ECOG performance status, n (%) 0 44/70 (62.9) 78/110 (70.9) 158/234 (67.5) 1 25/70 (35.7) 25/110 (22.7) 64/234 (27.4) 2 1/70 (1.4) 7/110 (6.4) 10/234 (4.3) 4 0 (0.0) 0 (0.0) 2/234 (0.9) Comorbidities, n (%) b Cardiovascular risk factors Hypertension 46 (54.8) 50 (41.3) 128 (47.6) Diabetes mellitus 17 (20.2) 24 (19.8) 51 (19.0) Cardiovascular disorders Dyslipidemia 27 (32.1) 31 (25.6) 72 (26.8) Atrial fibrillation 6 (7.1) 6 (5.0) 19 (7.1) Ischemic heart disease 4 (4.8) 7 (5.8) 13 (4.8) Stroke 1 (1.2) 4 (3.3) 7 (2.6) Heart failure 2 (2.4) 2 (1.7) 6 (2.2) Other arrythmias 2 (1.7) 2 (1.7) 4 (1.5) Other comorbidities Respiratory disease 17 (20.2) 22 (18.2) 51 (19.0) Gastrointestinal disease 15 (17.9) 15 (12.4) 43 (16.0) Concomitant treatment, n (%) b Antihypertensives 42 (50.0) 42 (34.7) 112 (41.6) Anticoagulants 8 (9.5) 6 (5.0) 21 (7.8) VKAs 4 (4.7) 5 (4.1) 10 (3.7) DOACs 1 (1.2) 1 (1.2) 6 (2.2) LMWH 3 (3.6) 0 (0.0) 5 (1.9) Antiplatelets 10 (11.9) 14 (11.6) 31 (11.5) Antibiotic/antiviral/antifungal therapy, n (%) 8 (9.5) 26 (21.5) 55 (20.4) Rai-Binet stage, n (%) Rai stage 0 - Binet stage A 36/83 (43.4) 64/118 (54.2) 128/260 (49.2) Rai stage I or II - Binet stage B 29/83 (34.9) 39/118 (33.1) 90/260 (34.6) Rai stage III or IV - Binet stage C 18/83 (21.7) 15/118 (12.7) 42/260 (16.2) Laboratory parameters c Median β2-microglobulin level (range), mg/L 3.8 (2.5-5.5) 3.3 (2.4-4.6) 3.3 (2.4-4.6) Median hemoglobin (range), g/dL 13.3 (12.0-14.6) 13.3 (11.6-14.6) 13.4 (11.9-14.6) Median platelets (range), x10 3 /μL 175.5 (139.3-226.3) 155.0 (112.5-208.0) 164.0 (117.0-214.0) Creatinine (mg/dL) 0.9 (0.8-1.1) 0.9 (0.8-1.1) 0.9 (0.8-1.1) Genomic aberrations, n (%) c Del(11q) deletion 11/80 (13.8) 22/114 (19.3) 45/254 (17.7) Del(17p)/TP53 mutation 55/83 (66.3) 27/117 (23.1) 95/260 (36.5) IGHV, n (%) Unmutated 45/58 (77.6) 63/82 (76.8) 147/186 (79.0) Mutated 13/58 (22.4) 19/82 (23.2) 39/186 (21.0) ( continued on next page ) e988 Clinical Lymphoma, Myeloma and Leukemia December 2021 Pau Abrisqueta et al Table 1 ( continued ) Variable First Line Second Line Overall Population (N = 84) (N = 121) (N = 269) Complex karyotype, n (%) d 4/67 (6.0) 13/102 (12.7) 18/227 (7.9) Molecular high-risk, n (%) e 74 (88.1) 80 (66.1) 199 (74.0) DOACs: direct oral anticoagulants; ECOG: Eastern Cooperative Group; IGHV = immunoglobulin heavy variable chain; LMWH = low-molecular-weight heparin; VKA = vitamin K antagonists; a Age at treatment initiation; b At ibrutinib treatment initiation; c At diagnosis; d Complex karyotype: ≥3 chromosomal abnormalities; e Unmutated IGHV, del(17p)/TP53 disruption, or complex karyotype. Table 2 Prior Therapy for CLL in the First- and the Second- Line Setting Treatment First Line Second Line N (%) N (%) (N = 185) (N = 64) Chemoimmunotherapy a 144 (77.8) 48 (75.0) FCR 75 (40.5) 6 (9.3) BR 29 (15.7) 28 (43.8) Clb-R 16 (8.6) 6 (9.3) R 8 (4.3) 2 (3.1) R-CHOP 7 (3.8) – G-Clb 5 (2.7) 0 (0.0) G-benda 2 (1.1) 4 (6.25) R-FCM 2 (1.1) 0 (0.0) R-CVP 2 (1.1) 0 (0.0) Chemotherapy b 38 (20.5) 11 (17.2) Clb 18 (9.7) 2 (3.1) FC 11 (5.9) 2 (3.1) Bendamustine 8 (4.3) 2 (3.1) Fludarabine 3 (1.6) 0 (0.0) Targeted agents 4 (2.2) 3 (4.7) Idelalisib-R 4 (2.2) 1 (1.5) Idelalisib 0 (0.0) 2 (3.1) Other therapies c 8 (4.3) 4 (6.3) Benda = bendamustine; BR = bendamustine plus rituximab; CHOP = cyclophosphamide, doxorubicin, vincristine, and prednisolone; Clb = chlorambucil; FC = fludarabinecyclophosphamide; CVP = cyclophosphamide, vincristine, and prednisone; FCM = fludarabine, cyclophosphamide, and mitoxantrone; G = obinutuzumab; R = rituximab a Chemoimmunotherapy regimens used in > 1 patient each; b Chemotherapy regimens used in > 1 patient each; c Other therapies used in one patient each had previously received CIT as first-line treatment, most commonly FCR (40.5%) and BR (15.7%). Forty-eight (75%) patients receiving ibrutinib as third-line treatment had been treated with CIT in the second line, most frequently BR (43.8%). Idelalisib was used in 4 and 3 patients in the first- and the second-line setting, respectively. Ibrutinib Treatment Patients initiated treatment with single-agent ibrutinib between June 2016 and January 2019. The median time from diagnosis to ibrutinib treatment initiation was 21 (IQR: 3.4-48.6) months. The median duration of ibrutinib treatment was 18.4 (IQR: 12.5-26.6) months (up to 40 months). At data cut-off, 220 (82.8%) patients remained on ibrutinib treatment while 49 (18.2%) patients had discontinued ibrutinib. The main reasons for treatment discontinuation were disease progression (16/269; 5.9%) and AEs (16/269; 5.9%). Four (4.8%) and 6 (4.9%) patients discontinued ibrutinib treatment due to AEs in the first- and second-line settings. Discontinuation due to disease progression occurred in 6 (7.1%) first-line patients and in 9 (7.4%) patients receiving ibrutinib in the secondline setting ( Table 3 ). The proportion of patients discontinuing treatment due to disease progression ( ≤65 years: 30.0%; > 65 years: 34.5%) and AEs ( ≤65 years: 30.0%; > 65 years: 34.5%) was not significantly different between patients aged ≤65 years and patients older than 65 years ( P = .811). Out the 16 patients who discontinued ibrutinib treatment due to disease progression (first-line: n = 6; second-line: n = 9), 9 (56.3%) patients harbored del(17p)/TP53 mutation (first-line: n = 5; second-line: n = 4), 2 (13.3%) patients had del(11q) (second-line: n = 2), and 7 (77.8%) patients carried unmutated IGHV (first-line: n = 3; second-line: n = 3). Dose reduction was required in 53 (19.7%) patients, and of these, only 7 patients (13.2%) needed a further dose reduction. The occurrence of AEs was the reason for dose reduction in 31 (11.5%; 31/269) patients. Overall, 13 (4.8%) and 18 (6.7%) patients required dose reductions due to hematological and nonhematological AEs, respectively. Eight (9.5%) and 14 (11.6%) patients required dose reductions due to AEs during first- and second-line ibrutinib treatment, respectively ( P = .819) ( Table 3 ). Ibrutinib dose was increased to 420 mg in 25 (47.2%) patients in whom dose reductions had previously been necessary (n = 53). Ibrutinib was temporarily interrupted in 107 (39.8%) patients, with 66 (61.7%) patients requiring one treatment interruption only. Of the treatment interruptions (n = 168), 25% (42/168) were due to major and/or minor surgical procedures. Temporary interruption of first- and second-line ibrutinib occurred in 27 (32.1%) and 52 (42.9%) patients, respectively. We observed a trend toward a higher rate of treatment interruptions due to AEs in the second line (21.5%) compared with the frontline setting (10.7%) ( P = .058) ( Table 3 ). Median time to treatment re-initiation after temporary interruption was 11 (6.2-21.3) days. Single-agent ibrutinib treatment was reintroduced at the standard dose of 420 mg in Clinical Lymphoma, Myeloma and Leukemia December 2021 e989 Real-World-Evidence of Ibrutinib for CLL treatment Table 3 Ibrutinib Treatment Modification and Discontinuation Treatment modification First Line Second Line Overall Population N (%) N (%) N (%) (N = 84) (N = 121) (N = 269) Dose reduction 17 (20.2) 22 (18.2) 53 (19.7) Patients with at least one dose reduction due to toxicity a 8 (9.5) 14 (11.6) 31 (11.5) Total number of dose reductions 18 24 60 Dose reductions due to toxicity b 8 (44.4) 16 (66.7) 34 (56.7) Hematological toxicity 4 (22.2) 7 (29.2) 16 (26.7) Non-hematological toxicity 4 (22.2) 9 (37.5) 18 (30.0) Dose increase after reduction b 7 (38.9) 12 (50.0) 33 (55.0) Temporal treatment interruption 27 (32.1) 52 (43.0) 107 (39.8) Patients with at least one interruption due to toxicity a 9 (10.7) 26 (21.5) 31 (11.5) Total number of treatment interruptions 39 87 168 Treatment interruptions due to toxicity c 11 (28.2) 38 (43.7) 63 (37.5) Hematological toxicity 10 (25.6) 13 (14.9) 19 (11.3) Non-hematological toxicity 2 (5.1) 25 (28.7) 46 (27.4) Treatment discontinuation 15 (17.8) 21 (17.3) 49 (18.2) Reasons for treatment discontinuation a Disease progression 6 (7.1) 9 (7.4) 16 (5.9) Adverse events 4 (4.8) d 6 (4.9) e 16 (5.9) Death 1 (1.2) 2 (1.7) 6 (2.2) Patient decision 0 (0.0) 1 (0.8) 1 (0.4) Other reasons 4 (4.8) 3 (2.5) 10 (3.7) a Percentages calculated over the total number of patients receiving ibrutinib in the overall population (n = 269), in the first line (n = 84) and the second-line setting (n = 121); b Percentages calculated over total number of dose reductions; c Percentages calculated over total number of interruptions; d Pancytopenia (n = 1), infection (UTI) (n = 1), esophagitis (n = 1), and ischemic cerebrovascular accident (n = 1); e gastrointestinal bleeding (n = 2), pneumonia (n = 1), infection (n = 1), and pleural effusion (n = 1). 84 (78.5%) patients whose treatment was temporarily interrupted (n = 107). Response to Treatment and Outcome ORR with single-agent ibrutinib was 79.2% (95% CI: 73.7%- 83.8%) (CR: 14.1%). ORR was 79.8% (CR: 16.7%) in the first line and 76.9% (CR: 13.2%) in the second line ( Table 4 ). With a median (range) follow-up of 19.2 (12.8-26.9) months (up to 40 months), the median PFS was not reached ( Figure 1 A) in either the first-line or second-line (Supplementary Figure 1), and estimated PFS rate at 24 months was 84.7% (95% CI: 79.2%- 90.1%). Similarly, median OS was not reached ( Figure 1 B), irrespective of the line in which ibrutinib was used (Supplementary Figure 1). At the time of analysis, 30 patients had died. Eleven (4.1%) patients died due to disease progression, and second neoplasia was the reason for death in two patients. Median time to subsequent CLL treatment was not reached. The age of patients at ibrutinib treatment ( ≤65 vs. > 65 years) did not have a significant impact either on PFS (p = 0.285) or OS ( P = .055), and the median PFS and OS were not reached, irrespective of the age of patients. Similarly, ORR was comparable between patients aged ≤65 years (95.9%) and patients older than 65 years (94.1%) ( P = .538) (Supplementary Table 1). Median PFS and OS were not reached regardless of whether patients had any cardiovascular disorder (hypertension, DM, AF, other arrhythmias, and/or stroke) before ibrutinib treatment initiation (n = 149) (Supplementary Table 2). ORR was not affected either by the presence of any cardiovascular disorder (affecting > 5 patients) (Supplementary Table 3). Subgroup analyses regarding high-risk genetic factors showed that overall response was not affected by either del(17p)/TP53 mutation ( P = .816) or unmutated IGHV ( P = .205). Similarly, the presence of del(11q) did not unfavorably affect treatment response ( P = .298) (Supplementary Table 4). The presence of complex karyotype (n = 18) did not impact response to treatment either ( P = .308) (Data not shown). Median PFS was not reached with single-agent ibrutinib, irrespective of the presence of del(17p)/TP53 mutation (p = 0.439), del(11q) ( P = .826), or unmutated IGHV ( P = .282). Similarly, none of these genetic alterations adversely affected OS, which was not reached in all subgroups ( Figure 2 ). Median PFS for patients without complex karyotype (n = 209) was not reached (95% CI: not reached [NR]-NR), while it was 28 months (95% CI: 17.4- e990 Clinical Lymphoma, Myeloma and Leukemia December 2021 Pau Abrisqueta et al Table 4 Summary of Response to Single-Agent Ibrutinib in the Overall Population and the First- and the Second-Line Setting Variable First-Line Second-Line Overall Population N (%) N (%) N (%) (N = 84) (N = 121) (N = 269) Response CR 14 (16.7) 16 (13.2) 38 (14.1) PR 27 (32.1) 30 (24.8) 85 (31.6) PR + lymphocytosis 12 (14.3) 17 (14.0) 33 (12.3) SD 1 (1.2) 3 (2.5) 5 (1.9) PD 0 (0.0) 4 (3.3) 4 (1.5) Refractoriness 0 (0.0) 2 (1.7) 2 (0.7) Not evaluated 13 (15.5) 17 (14.0) 40 (14.9) Death 3 (3.6) a 2 (1.7) b 5 (1.9) c Non-confirmed CR d 14 (16.7) 30 (24.8) 57 (21.2) ORR e 79.8 76.9 79.2 95% CI 69.6-87.8 68.3-84.0 73.7-83.8 CI = confidence interval; CR = complete response; ORR = overall response rate; PD = progressive disease; PR = partial response; SD = stable disease. a Due to disease progression in one patient b Due to disease progression in patients c Due to disease progression in 4 patients d Not confirmed by bone marrow biopsy or imaging (CT) e Including CR, non-confirmed CR, PR, and PR + lymphocytosis. Figure 1 Kaplan-Meier curves for progression-free survival (A) and overall survival (B) with single-agent ibrutinib. CI = confidence interval, NR = not reached. Patients were censored at the date of the last available follow up if still alive or without disease progression at the time of the analysis. Clinical Lymphoma, Myeloma and Leukemia December 2021 e991 Real-World-Evidence of Ibrutinib for CLL treatment Figure 2 Kaplan-Meier curves for progression-free survival according to the presence/absence of del(17p)/TP53 mutation (A) and del(11q) (C), and IGHV mutation status (E). Kaplan-Meier curves for overall survival according to the presence/absence of del(17p)/TP53 mutation (B) and del(11q) (D), and IGHV mutation status (F). CI = confidence interval, NR = not reached. Patients were censored at the date of the last available follow up if still alive or without disease progression at the time of the analysis. e992 Clinical Lymphoma, Myeloma and Leukemia December 2021 Pau Abrisqueta et al 40.0) for patients with a complex karyotype (n = 18), with no significant differences between these subgroups ( P = .174). The presence of complex karyotype did not have an adverse impact on OS either (NR [95% CI: NR-NR] vs. 31.3 [95% CI: 30.4-32.2], P = .127). Univariate COX regression analysis showed that none of the covariates assessed were significantly associated with PFS, regardless of the line in which ibrutinib was used. None of the variables achieving a statistical significance P < .2 in the univariate analysis were identified as independent factors adversely affecting PFS with single-agent ibrutinib in the multivariate analysis (Supplementary Table 5). Among patients who experienced disease progression on ibrutinib treatment (n = 19), 11 (57.9%) patients carried del(17p)/TP53 mutation, 4 (23.5%) patients had del(11q), and 3 (27.3%) patients harbored unmutated IGHV. A multivariate logistic regression analysis was performed to assess potential factors associated with disease progression, in which age, line of therapy, and cytogenetic characteristics (del(11q), del(17p)/TP53 mutation, and IGHV mutation status) were assessed. The multivariate analysis identified del(17p)/TP53 mutation as the only independent factor associated with disease progression (OR: 2.570, 95% CI: 0.995-6.635; P = .05), which was associated with a higher risk of disease progression (data not shown). Immune Reconstitution Mean IgA levels increased from 133.0 ±285 mg/dL at ibrutinib treatment initiation (n = 212) to 143.0 ±230.7 mg/dL at the end of treatment (n = 178). When paired analysis was performed (n = 165), we found that mean IgA levels significantly increased from the initiation of single-agent ibrutinib to the end of treatment (124.1 vs. 146.6 mg/dL, respectively; P < .001). The mean CD4/CD8 ratio was 1.6 at ibrutinib treatment initiation (n = 80), and 1.4 at the end of treatment (n = 42). Overall, 37 patients had available data for paired analysis, showing that the CD4/CD8 ratio did not change from ibrutinib treatment initiation to the end of treatment (1.3 vs. 1.2 respectively; p = 0.100). Postibrutinib Treatment for R/R CLL Sixteen (5.9%) patients received a further line of therapy for CLL after ibrutinib treatment discontinuation. The therapies (CIT, chemotherapy, and targeted agents) used after discontinuation of first- and second-line ibrutinib treatment are described in Supplementary Table 6. Safety A total of 188 (69.9%) patients experienced at least one AE during ibrutinib treatment. The most frequent AEs (any grade) (reported in > 10%) were infections (28.3%), bleeding (20.8%), diarrhea (14.9%), and arthralgia/myalgia (11.2%). AF and other arrhythmias of any grade occurred in 8 (3%) and 7 (2.6%) patients, respectively. Hypertension occurred in 11 (4.1%) patients. Overall, 83 (30.9%) patients experienced at least one grade 3 or higher AE, with infections (12.2%), neutropenia (7.0%), and bleeding (3.0%) being the most common (reported in ≥3%) ( Table 5 ). Overall, 67.9% (57/84) and 71.9% (87/121) of patients experienced at least one AE during first- and second-line ibrutinib treatment, respectively. The most common grade 3-4 AEs (reported in > 2%) were infections (first-line: 7.2%; second-line: 11.6%), and bleeding (first-line: 2.4%; second-line: 2.5%). Grade ≥3 AF was reported in one patient (1.2%) and 2 patients (1.7%) during first- and second-line ibrutinib, respectively. None of the patients experienced other arrhythmias of grade ≥3. Grade ≥3 hypertension occurred in one patient receiving second-line ibrutinib ( Table 5 ). Richter transformation was not reported in any patient. Of the 149 (55.4%) patients with baseline cardiovascular comorbidity (hypertension, DM, AF, other arrhythmias, and/or stroke), 6 (4%) patients developed AF (any grade) during ibrutinib treatment. The incidence of new-onset AF during ibrutinib treatment was not significantly associated with the presence of cardiovascular comorbidity at treatment initiation (p = 0.305) (data not shown). Overall, 56 (20.8%) patients experienced bleeding during ibrutinib therapy, mainly minor bleeding (grade 1 or 2) (17.5%). Major bleeding (grade ≥3) was reported in 7 (2.6%) patients. Minor bleeding occurred before major bleeding in 2 patients. The use of anticoagulants and/or antiplatelets was associated neither with the occurrence of bleeding ( P = .137) nor with the type of bleeding ( P = .579) (Supplementary Table 7). Overall, 66 patients were receiving anticoagulant and/or antiplatelet therapy during ibrutinib treatment, with 39 (14.5%) patients being treated with DOACs (apixaban: n = 17; dabigatran: n = 3; edoxaban: n = 2; rivaroxaban: n = 2). Three patients who were receiving VKAs (n = 1) and DOACs (n = 2) experienced major bleeding. Of these, one patient was treated with acenocoumarol, and one patient was given dabigatran while receiving first- and second-line ibrutinib treatment, respectively. A total of 167 infections (any grade) (infections: n = 131; respiratory infections; n = 36) occurred in 93 (34.6%) patients. Of the 131 infections detected, 98 (77.2%) were bacterial infections, mainly pneumonia (32.3%) and infections affecting the urinary tract (12.6%). Overall, 20.5% of infections reported were viral infections, most commonly influenza (6.2%) and herpes zoster (3.9%). Seven fungal infections were reported (noninvasive candidiasis: n = 5; invasive aspergillosis (IA): n = 1; mucormycosis: n = 1). Two (0.7%) patients experienced opportunistic infections (IA and mucormycosis), both reported in patients in the R/R setting. An opportunistic infection (IA) was reported in one patient receiving second-line ibrutinib who had been previously treated with highdose corticosteroids and alemtuzumab (Supplementary Table 8). Of note, the occurrence of infections was not significantly associated with the evolution of IgA levels from ibrutinib treatment initiation to treatment end (decrease, maintenance, increase) ( P = 0.301) (Data not shown). Grade ≥3 infections (any type of infection, including lower and upper respiratory tract infection) were reported in 37 (13.8%) patients (first-line: 8 [9.5%]; second-line: 15 [12.4%]; third-line: 14 [21.9%]). Of these, 14 (37.8%) patients carried del(17p)/TP53 mutation, 7 (19.4%) patients had del(11q), and 4 (17.4%) patients had unmutated IGHV. A multivariate logistic regression analysis where the treatment line and the abovementioned genetic characteristics were assessed showed that the line in which ibrutinib was Clinical Lymphoma, Myeloma and Leukemia December 2021 e993