Damle, Rajendra N.

Abstract Introduction Ibrutinib is a first-in-class, once-daily, oral, covalent inhibitor of BTK that has excellent single-agent activity in patients with previously treated CLL/SLL, based on results of published clinical studies. In the HELIOS trial, addition of ibrutinib to BR resulted in an 80% reduction in disease progression or death and confirmed for the first time, in a randomized setting, the benefit of ibrutinib-based therapy compared with standard chemoimmunotherapy (CIT) in previously treated patients (Chanan-Khan et al. ASCO 2015). In patients with CLL or SLL, deletion 17p (del17p) and 11q (del11q), complex karyotype, unmutated IgVH, and elevated ZAP70 are known high-risk prognostic factors. The current analysis reports on the efficacy of ibrutinib + BR vs placebo + BR in patients in the HELIOS trial with relevant high-risk biomarkers. Methods HELIOS is a randomized, double-blind, placebo-controlled, phase 3 study. Patients with active CLL/SLL following ≥ 1 prior therapy were randomized 1:1 to receive BR (≤ 6 cycles) with either ibrutinib (420 mg daily) (n = 289) or placebo (n = 289). Patients with del17p (> 20% of cells) were excluded. Ninety patients in the placebo arm with independent review committee (IRC)-confirmed progressive disease crossed over to ibrutinib, per protocol amendment. The primary end point was IRC-assessed progression-free survival (PFS), and overall survival (OS) was a secondary end point. A total of 287 patients in each arm had data available for at least 1 biomarker, and this population was used for the biomarker analyses. Correlation of biological risk factors at baseline with PFS and OS was analyzed using Kaplan-Meier analysis and curves compared using log-rank tests. Hazard ratios (HRs) were estimated using univariate Cox proportional hazards models. Results At a median follow-up of 17 months, IRC-assessed PFS was significantly longer with ibrutinib + BR vs placebo + BR in the overall study population (median not reached vs 13.3 months, respectively; HR: 0.203; 95% CI: 0.150-0.276; p < 0.0001). All subgroups of patients, including those with adverse prognostic parameters, e.g., del11q, complex karyotype, unmutated IgVH and elevated ZAP70 levels, had a significantly longer PFS with the addition of ibrutinib to BR as compared with placebo + BR (Table 1). As expected, each of these adverse prognostic parameters had a negative impact on PFS in the placebo + BR arm, e.g., the median PFS was shortest in patients with complex karyotype [8.5 months vs 13.8 months in patients without complex karyotype] and in patients with unmutated IgVH (11.3 months vs 22.1 months in patients with mutated IgVH). Interestingly, in the ibrutinib + BR arm, the adverse impact of these risk factors could not be detected (median PFS not reached irrespective of presence of risk factors). For example, in Figure 1 showing the PFS curves stratified by both del11q status and treatment, the outcome for patients in the ibrutinib + BR arm with del11q was similar to those without, with a trend toward better outcome in the del11q patients (e.g., longer PFS - not reached vs 24.9 months), unlike for patients in the placebo + BR arm (11.01 months vs 13.86 months). In patients with del11q, unmutated IgVH, or elevated ZAP70, there were also statistically significant benefits in OS for those receiving ibrutinib + BR vs placebo + BR (del11q: HR: 0.326, 95% confidence interval [CI], 0.122-0.870; p = 0.025; unmutated IgVH: HR: 0.515, 95% CI, 0.298-0.890: p = 0.017; elevated ZAP70, HR 0.536, 95% CI, 0.289-0.994: p = 0.048). Addition of ibrutinib also increased PFS in patient subgroups with other cytogenetic or clinical prognostic markers (such as del13q or bulky disease) compared with placebo. Conclusions All subgroups of patients, irrespective of adverse risk factors, such as del11q, complex karyotype, elevated ZAP70, and unmutated IgVH, benefit from the addition of ibrutinib to BR compared with placebo + BR. The negative impact of these known risk factors is apparent in patients in the placebo + BR arm, but is not seen in patients in the ibrutinib + BR arm. These results suggest that ibrutinib + BR is a suitable treatment regimen for all patients with previously treated CLL/SLL, including those with high-risk prognostic markers. Disclosures Cramer: Janssen: Other: Travel grant, Research Funding, Speakers Bureau; Hoffman LaRoche: Other: Travel grant, Research Funding, Speakers Bureau; Mundipharma: Other: Travel grant; Glaxo Smith Klein/Novartis: Research Funding; Astellas: Other: Travel grant; Gilead: Other: Travel grant, Research Funding. Fraser:Janssen: Honoraria, Research Funding, Speakers Bureau; Hoffman LaRoche: Consultancy, Honoraria; Celgene: Honoraria, Research Funding. Santucci Silva:Janssen: Other: Travel reimbursement, Research Funding; GSK: Research Funding; Celgene: Research Funding; Merck: Research Funding; Novartis: Other: Travel reimbursement; Hoffman LaRoche: Other: Travel reimbursement, Research Funding. Dilhuydy:Roche: Honoraria, Other: Travel reimbursement; Janssen: Honoraria, Other: Travel reimbursement; Mundipharma: Honoraria. Goy:Allos, Biogen Idec, Celgene, Genentech, and Millennium. Gilead: Speakers Bureau; Celgene: Consultancy, Research Funding, Speakers Bureau. Mato:Celgene: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding; Gilead: Consultancy, Other: Travel, Accommodations, Expenses; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: Travel, Accommodations, Expenses; TA Therapeutics: Research Funding. Damle:Janssen: Employment. Phelps:Janssen/J&J: Employment, Equity Ownership. Mahler:Janssen: Employment, Other: Travel reimbursement. Salman:Janssen/J&J: Employment, Equity Ownership. Schaffer:Janssen: Employment. Howes:Janssen/J&J: Employment, Equity Ownership. Balasubramanian:Pharmacyclics LLC, an AbbVie Company: Equity Ownership; Janssen: Employment, Equity Ownership.

Abstract Introduction Ibrutinib is a first-in-class, once-daily, oral, covalent inhibitor of Bruton's tyrosine kinase (BTK) that as a single agent has significantly improved overall survival in patients (pts) with both treatment naïve and relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). In the phase 3 HELIOS trial, the addition of ibrutinib to bendamustine + rituximab (BR) resulted in an 80% reduction in disease progression or death (HR, 0.203, 95% CI, 0.150-0.276; p < 0.0001) and confirmed for the first time, in a randomized setting, the benefit of ibrutinib-based therapy compared with standard chemoimmunotherapy in previously treated pts (Chanan-Khan, et al. Lancet Oncol. 2016;17(2):200-11). Independent Review Committee assessed progression-free survival (PFS) at 18 months was 79% (95% CI: 73%-83%) in the ibrutinib +BR (I+BR) arm and 24% (95% CI: 18%-31%) in the placebo + BR (P+BR) arm. While the activity of ibrutinib is primarily in B-cells where it inhibits BTK-dependent survival pathways, it may also have significant effects on the immune system by exerting an effect on T-cells (by inhibition of interleukin-2-inducible kinase and related shift from Th2 to Th1-based immunity, which in turn affects Treg and Th17 activity) and via normalization of immune function, thus affecting tumor response. Here, we report changes in circulating T-cell immunophenotypes in a subset of pts treated with either I+BR or P+BR in the HELIOS study. Methods HELIOS is a randomized, double-blind, placebo-controlled, phase 3 study. Pts with active CLL/SLL following ≥ 1 prior therapy were randomized 1:1 to receive BR (≤ 6 cycles) with either ibrutinib (420 mg daily; n = 289) or placebo (n = 289). Pts with del17p (> 20% of cells) were excluded. Peripheral blood was collected at the start of the study, at Cycle 1, Day 15 (C1D15) and at the end of treatment/time of progressive disease (EOT/PD). From these samples, peripheral blood mononuclear cells (PBMC) were separated and cryopreserved. PBMC were subjected to flow-cytometric analysis of T-cell subsets including CD4, CD8 and markers indicative of Treg cells (CD25+CD127low) and Th17 cells (CCR4+CCR6+). In addition, expression of T-cell checkpoints ICOS, PD-1 and OX-40 by CD4 and CD8 cells were evaluated as an indicator of cell activation or activation/exhaustion. The findings from the HELIOS study reported here are based on analysis of paired samples (C1D1 and C1D15) of 29 CLL cases from the I+BR arm and 22 cases from the P+BR arm. The Mann-Whitney U test was applied to determine the significance of the differences in each of T-cell subtype between the two arms. Results Overall, there was a net increase in the percentage of CD3+ cells with treatment in both the I+BR-treated pts and P+BR-treated pts, which was observed as early as Day 15 (+12.0% and +11.42% of total lymphocytes, respectively, at C1D15 compared with C1D1; Figure 1). The EOT/PD samples showed a continued increase in the percentage of CD3+ cells in the I+BR pts, the majority of whom (11/12) were responders, while the opposite trend was observed in the P+BR patients (8/21 responders). Focusing on the early changes in the analysis of T-cell subsets, a pronounced decrease in the percentage of Th17 CD4+ cells was noted in the I+BR pts (mean: -2.49%) but in the P+BR pts, an increase of this subset (mean: +2.66%) was observed (p = 0.011; Figure 2). When comparing other CD4+ subsets, decreases in Treg cells were seen in both pt groups, with a corresponding increase in the T-cell activation marker ICOS. Less significant changes were observed in the other T-cell markers studied, however, a trend to increased PD-1 was seen in the P+BR pts but not in the I+BR pts. The safety profile in these pts was consistent with previous reports for the study. Conclusions These results suggest that the addition of ibrutinib to BR helped restore T-cell proportions in this subset of cases and it is noteworthy that this effect was visible even within 15 days of initiation of therapy. Data from the I+BR pts showed a pronounced decrease in the percentage of Th17 CD4+ cells, which are primarily pro-tumorigenic but may sometimes have anti-tumor effects, and a concomitant decrease in the percentage of Treg cells, which may explain the overall increase in T-cell activation. These findings may also be related to the observed increase in PFS with the addition of ibrutinib to BR reported in the trial. Disclosures Damle: Janssen Research & Development: Employment. Schaffer:Janssen Research & Development: Employment. Chaturvedi:Janssen Research & Development: Employment. Phelps:Johnson & Johnson: Employment, Equity Ownership. Aquino:Janssen Research & Development: Employment. Mahler:Janssen Research & Development: Employment. Salman:Janssen Research & Development: Employment, Equity Ownership, Other: Travel, Accommodations, Expenses. Howes:Janssen Research & Development: Employment. Loscertales:Janssen Research & Development: Consultancy; Roche: Consultancy; Gilead: Consultancy; AbbVie: Consultancy. Trneny:Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen Research & Development: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Balasubramanian:Janssen Research & Development: Employment.