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Ristocetin-Induced Platelet Aggregation for Monitoring of Bleeding Tendency in CLL Treated with Ibrutinib

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Ristocetin-Induced Platelet Aggregation for Monitoring of Bleeding Tendency in CLL Treated with Ibrutinib OPEN Leukemia (2017) 31, 1117–1122 www.nature.com/leu ORIGINAL ARTICLE Ristocetin-induced platelet aggregation for monitoring of bleeding tendency in CLL treated with ibrutinib L Kazianka1,2, C Drucker3, C Skrabs1,2, W Thomas4, T Melchardt5, S Struve6, M Bergmann6, PB Staber1,2, E Porpaczy1,2, C Einberger1,2, M Heinz1,2, A Hauswirth1,2, M Raderer2,7, I Pabinger1,2, R Thalhammer8, A Egle5, C-M Wendtner6, G Follows4, G Hoermann8, P Quehenberger8, B Jilma3 and U Jaeger1,2 Bleeding because of impaired platelet function is a major side effect of the Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib. We quantitatively assessed ristocetin-induced platelet aggregation (RIPA) in 64 patients with chronic lymphocytic leukemia (CLL) under ibrutinib at 287 time points. Eighty-seven bleeding episodes in 39 patients were registered (85 Common Toxicity Criteria (CTC) grade 1 or 2, 2 CTC grade 3) during a median observation period of 10.9 months. At times of bleeding, RIPA values were significantly lower (14 vs 28 U; Po0.0001). RIPA was impaired in patients receiving concomitant antiplatelet therapy or anticoagulation (14 vs 25 U, P = 0.005). A gradual decline of median RIPA values was observed with increasing bleeding severity. Importantly, no CTC grade 2 or 3 bleeding were observed with RIPA values of 436 U. Sequential monitoring indicated a decrease of RIPA values from a median of 17 to 9 U within 2 weeks after initiation of treatment as well as an increase above the critical threshold of 36 U within 7 days when ibrutinib was paused. Low RIPA values were similar during treatment with another BTK inhibitor, CC292. Quantitative assessment of platelet function is a practical tool to monitor bleeding tendency under BTK-inhibitor therapy. Leukemia (2017) 31, 1117–1122; doi:10.1038/leu.2016.316 INTRODUCTION Of note, vWF antigen and activity in plasma remain within normal 17 Targeting Bruton’s tyrosine kinase (BTK) with the small-molecule range. The dependency of GPIb-IX-V signaling on BTK has also been 13 ibrutinib has significantly improved progression-free and overall shown in vivo using a BTK-deficient mouse model. However, there survival of patients with chronic lymphocytic leukemia (CLL) and is a possibility that TEC, another member of the TEC kinase family, mantle cell lymphoma and is currently investigated in other B-cell compensatesforthelossofBTKinplateletsasitisindicatedby 1–5 the partially preserved response to collagen in human X-linked lymphomas. The drug is now widely used in clinical routine. Its 18 mechanism of action is based on the inhibition of BTK as part of agammaglobulinemia patients. Nevertheless, the cysteine residue 6–10 that is required for the covalent binding of ibrutinib to an adenosine the B-cell receptor signaling cascade. BTK is also expressed in 12 – triphosphate-binding site can also be found in TEC. Taken together, other hematopoietic lineages, including platelets.11 13 Inhibition there is strong evidence that pharmacologic inhibition of BTK and of this kinase may therefore result in relevant hematologic side other TEC kinases by ibrutinib results in impaired platelet function. effects. Indeed, bleeding episodes were observed in 44% of Proper management of bleeding complications is important patients in the CLL registration trial1 and in up to 61% of patients 14 because they may affect the length and intensity of ibrutinib after a longer observation period. treatment. In addition, up to 50% of CLL patients with cardiovascular Bleeding is usually mild (Common Toxicity Criteria (CTC) grades comorbidities are under concomitant treatment with anticoagulants 1–2, corresponding to spontaneous bruising or petechiae), but 19,20 14 or platelet function inhibitors. more severe bleeding is observed in 8% of patients. CTC grade 3 We used an easy to perform method for quantitative assessment of 1,4,15 or 4 bleeding occurs in ∼ 5% of patients after trauma. vWF/ristocetin-induced platelet aggregation (RIPA) in ibrutinib-treated BTK is a TEC family kinase and acts as a signaling molecule CLL patients in order to (1) correlate the degree of impairment of in von Willebrand factor (vWF)- and collagen-induced platelet platelet function with bleeding tendency and (2) monitor platelet 12 activation. The corresponding receptors glycoprotein VI (GPVI, aggregation during drug therapy and before interventions. collagen receptor) and the glycoprotein Ib-IX-V complex (GPIb, vWF receptor) have previously been shown to be affected by BTK inhibition: in vitro binding of platelets from ibrutinib- SUBJECTS AND METHODS treated patients to vWF matrix was significantly impaired16 as Subjects well as platelet response to collagen using light transmission This observational study included 64 CLL patients from 4 different centers aggregometry.11 in 3 countries (Cambridge, Munich, Salzburg and Vienna). Patients received 1Department of Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Vienna, Austria; 2Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; 3Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria; 4Cambridge University Hospitals, NHS Foundation Trust, Cambridge, UK; 5Department of Medicine III, Paracelsus Medical University, Salzburg, Austria; 6Klinikum Schwabing, Academic Teaching Hospital of the University of Munich, Munich, Germany; 7Department of Medicine I, Division of Oncology, Medical University of Vienna, Vienna, Austria and 8Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria. Correspondence: Professor U Jaeger, Department of Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna Austria. E-mail: [email protected] This work has been presented in part at the 57th Annual Meeting of the American Society of Hematology in Orlando 2015. Received 10 May 2016; revised 28 September 2016; accepted 5 October 2016; accepted article preview online 2 November 2016; advance online publication, 2 December 2016 Platelet function and ibrutinib L Kazianka et al 1118 ibrutinib at a target dose of 420 mg daily and were either included in the of the performed aggregation tests were 44–176 U for RIPA and 22–110 U RESONATE study (28 patients), in the ibrutinib named patient program for collagen-induced platelet aggregation in healthy volunteers.21 The (12 patients) or received ibrutinib in routine clinical use according to the measured area under the curve allows quantification of platelet function. licensed indication in Europe (24 patients). Of the patients, 18% were RIPA and collagen-induced platelet aggregation were performed for this previously untreated but had a 17p deletion or TP53 mutation, whereas study. Importantly, test results are dependent on platelet function and 82% had relapsed or refractory CLL with or without 17p/TP53 aberrations. platelet count22,23 and the assessment has to be performed on fresh whole The study was approved by the ethics committee of the Medical University blood locally. of Vienna (ethics committee Nr 1631/2012 and 11/2005) and informed consent was obtained. Eleven patients had multiple measurements before Reproducibility. Variability of the RIPA test was evaluated in Vienna start and during ibrutinib therapy and 53 patients were investigated under in five healthy donors and six patients under ibrutinib. A total of stable ibrutinib intake. – Patients were seen regularly (at least monthly) in their corresponding 4 10 measurements were performed from the same time point and on centers. Bleeding tendency was recorded at each time point by standard- consecutive days in healthy donors. In total, median values for healthy fi ized questions including bruising, petechiae and epistaxis, and a physical donors ranged from 81.9 to 133.0 U with an intraindividual coef cient of examination was performed. Clinical information included clinical stage, variation of 7.6 to 9.1%. Median values for the 6 patients were 4.1 to 37.5 U fi genetics, lines of therapy and concomitant treatment, particularly therapy with a coef cient of variation from 11.2 to 15.6% in 5 patients. In one fi with antiplatelet agents or anticoagulants. Patient characteristics are patient with very low values the results varied from 1 to 8 U (coef cient of shown in Table 1. Severity of bleeding was scored according to the CTC variation 49.4%), but still stayed in the same range. In addition, vWF antigen and activity were assessed by standard grading scale (version 4.03: 14 June 2010) used in the RESONATE protocol. 24 Controls included 13 CLL patients currently not on treatment, 11 methods as described previously. patients receiving other treatments for CLL (4 with immunochemotherapy (rituximab plus fludarabine/cyclophosphamide or bendamustin) and 7 with Statistical methods phosphatidylinositol-3-kinase inhibitors (idelalisib, duvelisib)) as well as 1 Statistical analysis was performed using JMP Statistics (SAS Corporation, fi patient with X-linked agammaglobulinemia and proven BTK protein de ciency. Cary, NC, USA) software. Statistical methods comprised χ2 analysis or Fisher’s exact test to compare baseline characteristics, and t-test or Platelet function assessments analysis of variance where applicable for RIPA analysis. Correlations were Fresh blood specimens (5 ml) for analysis of platelet function were drawn determined by Pearson’s r. The P-values of o0.05 (two sided) were into hirudine containing tubes (Vacuette, Kremsmuenster, Austria) and considered statistically significant.
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