Interleukin-2 Inducible Kinase Research Articles

Effect of Interleukin-2 Inducible Kinase (ITK) on the Temporal Dynamics of TCR Signaling in CD8 T cells

Abstract Antigen affinity has been linked to the rate of downstream TCR activation and the activation of transcription factors such as NFAT and NF-kb. Interleukin-2 inducible T cell kinase (ITK) plays a key role in the differential rate and magnitude of TCR-dependent transcription factor activation, especially when T cells are stimulated with lower affinity ligands. The Nr4a3-Tocky Timer mouse model carries a construct for a fluorescent protein controlled by the Nr4a3 promoter. Nr4a3 is highly expressed following TCR activation and thus is a good metric for TCR signaling. When first produced, the Tocky protein fluoresces “blue,” at peak wavelength 466nm and then, after ~7hrs, degrades to a “red” fluorescence at peak wavelength 583nm. Splenocytes were harvested from OT-I RAG1KO mice crossed to Nr4a3-Tocky mice and stimulated using varying affinities and doses of ova peptide over 7 days in vitro. Cells were exposed to the ITK inhibitor, PRN694, to observe the effect of ITK on the rate of expression of Tocky fluorescence along with activation surface markers CD69, CD25, CD44, and CD122. With ITK inhibition, CD8 T cells expressed the “Blue” protein slower and in fewer cells compared to OT-I cells stimulated without PRN694 at 4hrs. At 48hrs after stimulation, sustained signaling was observed in control cells, whereas a subset of ITK-inhibited cells showed evidence of halted TCR-induced Tocky transcription. This decrease in the longevity of TCR signaling was more evident when lower peptide doses or lower affinity peptides were used for stimulation. These results suggest that ITK plays a role in amplifying the initial TCR signal, and is also required for sustained signaling after TCR activation in CD8 T cells, resulting in the tuning of early gene expression. Supported by grants from the NIH (Dissecting the pathways controlling tunable responses to TCR signaling: 5R01AI132419-06)

Ibrutinib for Steroid Refractory Chronic Graft Vs Host Disease - Real World Experience

Background and aims: Chronic graft vs host disease (cGVHD) is a common complication following allogeneic haematopoietic stem cell transplantation (HSCT), occurring in 30-70% of recipients receiving T cell replete grafts [1]. While corticosteroids are the backbone of first line therapy for cGVHD, less than 20% of patients achieve a durable partial or complete response with this therapy alone [2]. Despite the advent of novel agents for second line therapy of steroid refractory cGVHD (SR-cGVHD), disease progression is not uncommon highlighting an unmet clinical need. GVHD is believed to be mediated by donor derived alloreactive B and T cells. Ibrutinib is a first in class Bruton tyrosine kinase (BTK) inhibitor, with additional inhibitory effects on other tyrosine kinases such as interleukin-2 inducible kinase (ITK). BTK and ITK play important roles in B and T cell stimulatory signalling pathways respectively. Inhibition of these pathways in alloreactive B and T cell clones may ameliorate cGVHD, and in recent phase 1b/II clinical trials in SR-cGVHD ibrutinib has demonstrated response rates of 60-70% [3]. The outcomes in real world clinical practice may differ from those observed in trials, as patients may have received more lines of cGVHD therapy or have different comorbidities affecting tolerability. We assessed the efficacy and tolerability of ibrutinib given for SR-cGVHD in a real world cohort of Australian patients. Methods: A retrospective review of pharmacy dispensing records was undertaken at six allogeneic bone marrow transplantation centres across Australia between Jan 2018 and Jan 2020 to identify patients treated with ibrutinib on compassionate access for SR-cGVHD. Clinical records of identified patients were reviewed to extract data using standardised case report forms including transplant details, cGVHD manifestations and treatment history, cGVHD response to ibrutinib (as per NIH cGVHD consensus criteria [4]), adverse events, relapse and survival. Results: Demographic details of the 41 eligible patients are outlined in Figure 1. The majority (95%) had extensive cGVHD with a median of 3 lines of systemic therapy (range 2-8) preceding ibrutinib. The median starting dose of ibrutinib was 420mg daily (range 140 - 420mg daily), with an overall response rate of 44%, with a complete response seen in 5% (Figure 2). Corticosteroid dosing information was available for 20 patients, with a mean reduction in dose of 44% during ibrutinib treatment. There were a total of 50 adverse events in 22 patients, of which 48% were infections. After a median follow up of 412 days, 46% of patients were continuing ibrutinib, with the most common reasons for cessation being toxicity (32%) or progressive cGVHD (27%). At last follow up, 32/41 patients were alive, with causes of death being cGVHD (6 patients), infection (2 patients) and secondary malignancy (1 patient). Conclusion: Ibrutinib demonstrates modest activity in a real world setting of heavily pre-treated patients with SR-cGVHD. Toxicities, particularly those related to infections, appear to limit long term use. This study highlights the potential limitations of the use of ibrutinib for SR-cGVHD in a real world context, particularly with reference to tolerability in heavily pre-treated patients.

Tumor-infiltrating lymphocytes are functionally inactivated by CD90+ stromal cells and reactivated by combined Ibrutinib and Rapamycin in human pleural mesothelioma

Rationale: Despite evidence suggesting that the tumor microenvironment (TME) in malignant pleural mesothelioma (MPM) is linked with poor prognosis, there is a lack of studies that functionally characterize stromal cells and tumor-infiltrating lymphocytes (TILs). Here, we aim to characterize the stromal subsets within MPM, investigate their relationship to TILs, and explore the potential therapeutic targets.Methods: We curated a core set of genes defining stromal/immune signatures expressed by mesenchymal cells within the TME using molecular analysis of The Cancer Genome Atlas (TCGA) MPM cohort. Stromal and immune profiles were molecularly characterized using flow cytometry, immunohistochemistry, microarray, and functionally evaluated using T cell-activation/expansion, coculture assays and drug compounds treatment, based on samples from an independent MPM cohort.Results: We found that a high extracellular matrix (ECM)/stromal gene signature, a high ECM score, or the ratio of ECM to an immune activation gene signature are significantly associated with poor survival in the MPM cohort in TCGA. Analysis of an independent MPM cohort (n = 12) revealed that CD8+ and CD4+ TILs were characterized by PD1 overexpression and concomitant downregulation in degranulation and CD127. This coincided with an increase in CD90+ cells that overexpressed PD-L1 and were enriched for ECM/stromal genes, activated PI3K-mTOR signaling and suppressed T cells. Protein array data demonstrated that MPM samples with high PD-L1 expression were most associated with activation of the mTOR pathway. Further, to reactivate functionally indolent TILs, we reprogrammed ex vivo TILs with Ibrutinib plus Rapamycin to block interleukin-2-inducible kinase (ITK) and mTOR pathways, respectively. The combination treatment shifted effector memory (TEM) CD8+ and CD4+ TILs towards T cells that re-expressed CD45RA (TEMRA) while concomitantly downregulating exhaustion markers. Gene expression analysis confirmed that Ibrutinib plus Rapamycin downregulated coinhibitory and T cell signature pathways while upregulating pathways involved in DNA damage and repair and immune cell adhesion and migration.Conclusions: Our results suggest that targeting the TME may represent a novel strategy to redirect the fate of endogenous TILs with the goal of restoring anti-tumor immunity and control of tumor growth in MPM.

C‐5 Aryl Substituted Azaspirooxindolinones Derivatives: Synthesis and Biological Evaluation as Potential Inhibitors of Tec Family Kinases

AbstractThe interleukin‐2‐inducible kinase (ITK) and Bruton tyrosine kinase (BTK) are two crucial Tec family kinase members with important roles in the development of hematopoietic malignancies, autoimmune disorders and other diseases in humans. Thus, ITK and BTK are key targets for drug development. Spirooxindoles are important scaffolds for the synthesis of small molecules with broad and potent biological activities. In this study, we performed a structure‐activity relationship study of a new series of 5′‐(benzo[d][1,3]dioxol‐5‐yl)spiro[piperidine‐4,3′‐pyrrolo[2,3–b]pyridin]‐2′(1′H)‐one linked with N‐acyl and C‐5 aryl‐substituted scaffolds in a panel of ITK and BTK cancer cell lines. Four compounds 11, 12, 14, and 15 showed high antiproliferative activity against ITK and BTK cell lines. Compounds 11 and 12 with a C‐5 benzodioxole group and gem‐dialkyl group attached to carbonyl on piperidine were highly effective in ITK‐high Jurkat and CEM cell lines, and compound 14, a biotin analogue, was identified as a good inhibitor of BTK‐high RAMOS cells. Compound 15 with cyclopropyl group attached to carbonyl on piperidine also showed good activity in ITK and BTK cell lines.

A Phase 1 Trial of the Combination of Ibrutinib and Azacitidine for the Treatment of Higher Risk Myelodysplastic Syndromes: University of California Hematologic Malignancies Consortium (UCHMC) Study 1503

Introduction: Higher risk myelodysplastic syndromes (HR-MDS) have poor outcomes, particularly after hypomethylating agent (HMA) failure. The HMA azacitidine (AZA) is a standard of care for HR-MDS and works through several mechanisms, including inhibition of NF-kB signaling. Ibrutinib (IBR) inhibits Bruton9s Tyrosine Kinase (BTK) and has an antiproliferative effect on myeloblasts in preclinical models through BTK binding and inhibition of NF-kB signaling. IBR also has immunomodulatory activity mediated through binding interleukin-2-inducible kinase (ITK) and promoting Th1-polarized immunity, which is decreased in HR-MDS. These features suggest that the combination of IBR and AZA may improve outcomes in HR-MDS. Methods: This is an ongoing multicenter prospective Phase 1 dose-escalation trial of IBR in combination with AZA in patients with HR-MDS (NCT02553941). Results of the dose escalation phase are reported. Eligibility included World Health Organization or French-American-British classification-defined MDS and Revised International Prognostic Scoring System (IPPS-R) intermediate or higher risk. Any prior therapy was allowed or patients could be untreated if unfit for, or had refused, high intensity chemotherapy. Transfusion-dependent patients were eligible. Patients received AZA 75 mg/m2 IV/SC daily for 7 days and IBR orally daily for 28 days. Cycles repeated every 28 days. Dose-escalation used a 3+3 design with IBR dose levels of 420 mg (Cohort 1) and 560 mg (Cohort 2). The primary objective was to determine the safety and tolerability of IBR in combination with AZA. Adverse events (AEs) were monitored throughout treatment, and dose-limiting toxicities (DLT) were assessed during cycle 1. The secondary objective was to assess preliminary efficacy using modified International Working Group Response Criteria. Exploratory objectives evaluated pharmacodynamic and biological effects of the combination, including BTK occupancy in CD34+ bone marrow mononuclear cells (BMMC). Results: As of June 1, 2017, 9 patients [89% male, median age 80 years (range 64-81)] were enrolled into Cohort 1 (n=3) and Cohort 2 (n=6). MDS subtypes included single lineage dysplasia (n=1), multilineage dysplasia (n=1), excess blasts (EB)-1 (n=2), EB-2 (n=3), refractory anemia with EB in transformation (n=1) and unclassifiable (n=1). IPSS-R scores were intermediate (n=2), high (n=2) and very high (n=5). Three patients were HMA-naive and six had prior HMA therapy [AZA (n=3), decitabine (n=2), both (n=1)]. All patients completed cycle 1. No DLTs were observed. All patients experienced at least one treatment-emergent adverse event (TEAE). Seven patients experienced a grade 3-4 TEAE with neutropenia (n=6), thrombocytopenia (n=3) and febrile neutropenia (n=3) most common. Four patients (three in Cohort 1 and one in Cohort 2) experienced a serious adverse event including febrile neutropenia (n=3) and gastric hemorrhage (n=1). No patients experienced atrial fibrillation. Median time on study was 160 days (range 42-283) with a median of five cycles (range 1-10) received. Six patients remain on IBR plus AZA, and three patients have discontinued study therapy (two disease progression and one withdrawal of consent and subsequent death on hospice). Four patients have reduced AZA to 5 days per cycle per investigator discretion, and four patients have had interruptions of IBR dosing due to febrile neutropenia (n=3) and concurrent azole use (n=1). Three patients (33%) achieved complete remission (CR), one (11%) had a partial remission (PR), and five (55%) had stable disease (SD). All three CRs occurred in patients without prior HMA exposure and included one complete and two partial cytogenetic responses. CR was achieved after 1, 4 and 6 cycles in these patients. One patient (11%) with SD had a hematologic improvement-erythroid response (HI-E). The overall hematologic normalization rate (CR+PR+HI) was 55%. BTK occupancy in CD34+ BMMC after cycle 1 was 42.0% and 51.7% in two patients at IBR 420 mg and 41.5% in one patient at IBR 560 mg. Conclusions: The combination of IBR and AZA demonstrates a tolerable safety profile in patients with HR-MDS. No DLTs were observed at either IBR dose level. The combination shows promising preliminary efficacy, including responses in patients with prior HMA exposure. CD34+ BMMC BTK occupancy was seen. An expansion cohort at the IBR 560 mg dose level in AZA-naive patients is ongoing. Disclosures Jonas: AbbVie, Celgene, Daiichi Sankyo, Pharmacyclics, Genentech/Roche, Glycomimetics, Esanex, Kalobios: Research Funding; Celgene: Membership on an entity9s Board of Directors or advisory committees; Rigel: Consultancy. Logan: Novartis: Consultancy, Research Funding; Incyte: Consultancy; Astellas: Research Funding; Shire: Consultancy; Kite: Research Funding; Amgen: Consultancy; Pharmacyclics: Research Funding; Jazz: Consultancy. Abedi: Takeda: Speakers Bureau; Seattle Genetics: Speakers Bureau; Gilead: Speakers Bureau; BMS: Speakers Bureau; Amgen: Research Funding; Celgene: Membership on an entity9s Board of Directors or advisory committees, Research Funding, Speakers Bureau; California Institute of Regenerative Medicine: Research Funding. Bejar: Celgene: Consultancy, Honoraria, Other: DSMB, Steering Committee, Research Funding; Genoptix: Consultancy, Honoraria, Patents & Royalties; AbbVie/Genetech: Honoraria, Other: Ad-hoc advisory board; Foundation Medicine: Honoraria, Other: Ad-hoc advisory board; Otsuka/Astex: Honoraria, Other: Ad-hoc advisory board; Modus Outcomes: Consultancy, Honoraria. Wieduwilt: Reata Pharmaceuticals: Equity Ownership; Sigma-Tau: Research Funding. Curtin: Amgen, Celgene, Onconova, Pharmacyclics: Research Funding.

A Phase 2 Trial of Ibrutinib and Nivolumab in Patients with Relapsed or Refractory Classical Hodgkin's Lymphoma

A Phase 2 Trial of Ibrutinib and Nivolumab in Patients with Relapsed or Refractory Classical Hodgkin's Lymphoma

Ibrutinib treatment inhibits breast cancer progression and metastasis by inducing conversion of myeloid‐derived suppressor cells to dendritic cells

Ibrutinib is a known irreversible inhibitor of Bruton tyrosine kinase (BTK) and interleukin‐2‐inducible kinase (ITK). Ibrutinib has multiple immunomodulatory effects and is currently approved for treatment of chronic lymphocytic leukemia (CLL) and other cancers. Although previous studies have shown that ibrutinib inhibits growth of breast cancer cells, its impact on treatment of breast cancer and its metastasis is not determined. Myeloid‐derived Suppressor Cells (MDSCs) are immature myeloid cells present in tumors that can subdue the development of important tumoricidal cell populations, and their presence has been linked to poor prognosis in human and murine models. Here, using an orthotopic mouse breast cancer model, we show that ibrutinib effectively inhibits progression and metastasis of breast cancer. Mice treated with Ibrutinib display significantly lower tumor burdens and metastasis compared to controls. Furthermore, spleens and tumors from Ibrutinib‐treated mice showed higher numbers of mature DCs and lower numbers of myeloid‐derived suppressor Cells (MDSCs) which promote disease progression and are linked to poor prognosis in human and murine models. We also confirmed that ex vivo treatment of MDSCs with ibrutinib switched their phenotype to mature DCs and significantly enhanced MHCII expression. Further, ibrutinib treatment promoted T cell proliferation and effector functions leading to induction of anti‐tumor TH1 and CTL immune responses. Taken together, our results indicate that Ibrutinib inhibits tumor development and metastasis in breast cancer by promoting development of mature DCs from MDSCs and hence could be a novel therapeutic agent for treatment of breast cancerSupport or Funding InformationPharmacyclics LLC, an AbbVie Company

Ibrutinib treatment inhibits breast cancer progression and metastasis by inducing conversion of myeloid-derived suppressor cells to dendritic cells

BackgroundIbrutinib is a Bruton’s tyrosine kinase (BTK) and interleukin-2-inducible kinase (ITK) inhibitor used for treating chronic lymphocytic leukaemia (CLL) and other cancers. Although ibrutinib is known to inhibit the growth of breast cancer cell growth in vitro, its impact on the treatment and metastasis of breast cancer is unclear.MethodsUsing an orthotopic mouse breast cancer model, we show that ibrutinib inhibits the progression and metastasis of breast cancer.ResultsIbrutinib inhibited proliferation of cancer cells in vitro, and Ibrutinib-treated mice displayed significantly lower tumour burdens and metastasis compared to controls. Furthermore, the spleens and tumours from Ibrutinib-treated mice contained more mature DCs and lower numbers of myeloid-derived suppressor cells (MDSCs), which promote disease progression and are linked to poor prognosis. We also confirmed that ex vivo treatment of MDSCs with ibrutinib switched their phenotype to mature DCs and significantly enhanced MHCII expression. Further, ibrutinib treatment promoted T cell proliferation and effector functions leading to the induction of antitumour TH1 and CTL immune responses.ConclusionsIbrutinib inhibits tumour development and metastasis in breast cancer by promoting the development of mature DCs from MDSCs and hence could be a novel therapeutic agent for the treatment of breast cancer.

Harnessing the Effects of BTKi on T Cells for Effective Immunotherapy against CLL.

B-cell receptor (BCR) signaling and tumor–microenvironment crosstalk both drive chronic lymphocytic leukemia (CLL) pathogenesis. Within the microenvironment, tumor cells shape the T-cell compartment, which in turn supports tumor growth and survival. Targeting BCR signaling using Bruton tyrosine kinase inhibitors (BTKi) has become a highly successful treatment modality for CLL. Ibrutinib, the first-in-class BTKi, also inhibits Tec family kinases such as interleukin-2–inducible kinase (ITK), a proximal member of the T-cell receptor signaling cascade. It is increasingly recognized that ibrutinib modulates the T-cell compartment of patients with CLL. Understanding these T-cell changes is important for immunotherapy-based approaches aiming to increase the depth of response and to prevent or treat the emergence of resistant disease. Ibrutinib has been shown to improve T-cell function in CLL, resulting in the expansion of memory T cells, Th1 polarization, reduced expression of inhibitory receptors and improved immune synapse formation between T cells and CLL cells. Investigating the modulation of BTKi on the T-cell antitumoral function, and having a more complete understanding of changes in T cell behavior and function during treatment with BTKi therapy will inform the design of immunotherapy-based combination approaches and increase the efficacy of CLL therapy.

Bruton tyrosine-kinase inhibitor on the rise: acalabrutinib in Waldenström macroglobulinemia

Bruton tyrosine-kinase inhibitor on the rise: acalabrutinib in Waldenström macroglobulinemia

A Phase 1 Trial of Ibrutinib (IBR) and Azacitidine (AZA) for the Treatment of Higher-Risk Myelodysplastic Syndromes (HR-MDS): Updated Results of University of California Hematologic Malignancies Consortium (UCHMC) Study 1503

A Phase 1 Trial of Ibrutinib (IBR) and Azacitidine (AZA) for the Treatment of Higher-Risk Myelodysplastic Syndromes (HR-MDS): Updated Results of University of California Hematologic Malignancies Consortium (UCHMC) Study 1503

Comparison of interleukin-2-inducible kinase (ITK) inhibitors and potential for combination therapies for T-cell lymphoma

Patients with peripheral T-cell lymphomas generally have poor clinical outcomes with conventional chemotherapy. Recent advances have demonstrated that a large subgroup of PTCL are derived from follicular helper (Tfh) T-cells. These cases show a characteristic pattern of gene expression, which includes high-level protein expression of interleukin-2-inducible kinase (ITK). ITK is a member of the TEC family of kinases and normally has essential functions in regulating T-cell receptor signalling and T-cell differentiation. Here we report a side-by-side comparison of four ITK inhibitors. We investigate effects on apoptosis, phosphorylation of signaling molecules, calcium flux and migration. In line with a specific mechanism of action ONO7790500 and BMS509744 did not inhibit MEK1/2 or AKT phosphorylation although other ITK inhibitors, ibrutinib and PF-06465469, did have this effect. Specific ITKi had modest effects on apoptosis alone but there was definite synergy with doxorubicin, pictilisib (PI3Ki) and idelalisib (PI3Kδi). ITKi repressed migration of Jurkat cells caused by CXCL12 and the CXCR4 antagonist, plerixafor enhanced this effect. Overall ITKi may have several mechanisms of action that will be therapeutically useful in PTCL including reduction in survival and perturbation of trafficking.

Phase II Study of Brentuximab Vedotin Plus Ibrutinib for Patients with Relapsed/Refractory Hodgkin Lymphoma

Background:Brentuximab vedotin (BV), an antibody drug conjugate (ADC), selectively delivers anti-tubulin agent monomethyl auristatin E (MMAE) to CD 30+ cells. In a a multi-center phase II trial in patients with relapsed/refractory Hodgkin lymphoma (HL), BV showed an overall response rate (ORR) of 75%, a complete response (CR) rate of 34%, and a median duration of response (DOR) of 6.7 months (Younes A et al, JCO 2012). Although this drug has high ORR in HL, the CR rate and the DOR can be improved.Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, has demonstrated antitumor activity in B-cell lymphomas. Ibrutinib is also an irreversible inhibitor of interleukin-2-inducible kinase (ITK), which has a critical role in T cell signaling. Inhibition of ITK leads to increased Th1 based immune response (Dubovsky JA, Blood 2013). As a single agent at standard dose, ibrutinib does not have antitumor activity in HL cell line (Figure 1). However, we have shown that standard dose ibrutinib is synergistic with BV in L428, a HL cell line (Figure 1). Based on our preclinical model, we hypothesize that ibrutinib may enhance the antitumor activity of BV in HL patients. It is also possible Ibrutinib may enchance the activity of BV through ITK inhibition of T cells in the HL microenvironment. Thus we designed and conducted a phase II trial using the combination of ibrutinib plus BV in patients with R/R HL. We report the planned interim analysis of efficacy and safety.Patients and Methods:This is a prospective, multicenter phase II trial with a 3-patient lead-in cohort in patients with relapsed/refractory HL. All patients must be > 15 years old and have biopsy proven relapsed/refractory HL. Patients are treated with 1.8 mg/kg of BV intravenously every 3 weeks and ibrutinib 560 mg PO daily (420 mg PO daily in the lead-in cohort). Patients could have received prior BV. The primary endpoint was the CR rate according to Lugano 2014. Secondary endpoints were toxicities, ORR, duration of response, and, BTK/ITK receptor occupancy, and changes in T/B/NK cell subsets in peripheral blood.Results:Sixteen out of 39 patients were accrued thus far, all 16 pts were evaluable for toxicity, and 13 patients were evaluable for efficacy (3 lead-in pts excluded). The baseline characteristics (Figure 1) are: male (56%), Caucasian (75%), median age of 33 (17-69), stage III/IV at diagnosis (50%), primary refractory to induction (50%), refractory to last therapy (37%), and 4 patients had prior BV (25%). The overall best response (CR+PR) rate was 69%, CR rate was 46%, stable disease rate was 31%, and no progressive disease (PD) was seen. The disease control rate (CR+PR+SD) was 100%. One patient who was refractory to prior BV achieved a PR, and an additional patient who had a previous best response of PR to BV now achieved a CR.Treatment was well tolerated. There were no Grade 4 events. Grade 3 possibly-related toxicities included neutropenia (n=2) and hypokalemia (n=1). Grade I/II possibly related toxicities >20% included diarrhea (n=8, 7 grade 1), nausea (n=6, all grade 1), fatigue (n=5, all grade 1), rash (n=5, 4 grade 1), and thrombocytopenia (n=4, all grade 1).Conclusion:The combination of BV + ibrutinib is well tolerated. Although the ORR of 69% maybe similar to BV alone, the CR of 46% and disease control rate of 100% appears promising. Especially encouraging is the 1 PR and 1 CR seen in patients previously exposed to BV. The study has met the interim analysis endpoint and warrants further accrual to investigate the final CR rate. [Display omitted] DisclosuresChen:Pfizer: Consultancy; Merck: Consultancy, Speakers Bureau; Genentech: Speakers Bureau; Seattle Genetics: Consultancy, Research Funding, Speakers Bureau; Affimed: Research Funding; Pharmacyclics: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding. Herrera:Seattle Genetics: Research Funding; Merck: Consultancy; Genentech: Consultancy; BMS: Consultancy; Pharmacyclics: Consultancy. Kwak:Pepromene Bio: Consultancy, Equity Ownership; Celltrion, Inc: Consultancy; InnoLifes: Consultancy, Equity Ownership.

Incidence and Type of Opportunistic Infections during Ibrutinib Treatment at a Single Academic Center

BACKGROUNDIbrutinib is an irreversible inhibitor of Burton's tyrosine kinase (BTK) in the B-cell receptor (BCR) signaling cascade and is a practice changing treatment for chronic lymphocytic leukemia (CLL) and other B-cell malignancies. Ibrutinib also inhibits Interleukin-2 Inducible Kinase (ITK) in T-cells and has demonstrated immunomodulatory effects. Recently, cases of opportunistic infections (OI) have been reported during ibrutinib treatment including pneumocystis jirovecii pneumonia (PJP), cryptococcus, and fusarium. To date there are no reports on OI in large unselected cohorts of patients taking ibrutinib. We conducted a single-institution retrospective study to determine the incidence and type of OI during ibrutinib treatment as well as outcomes and characteristics associated with risk. METHODSWe reviewed medical records of all patients treated with ibrutinib at the Ohio State University between June 1st 2010 and March 31st 2016. Patients who received ibrutinib for graft versus host disease were excluded. All charts were initially reviewed by one of the investigators and patients with OI were independently reviewed by a second investigator. Baseline patient and disease characteristics were captured at time of starting ibrutinib. All OI occurring after the first dose of ibrutinib were recorded. Onset of OI was considered as the time of first presentation for a complaint related to OI. Time to OI was calculated from the date of starting ibrutinib until the onset of OI or censored at the last assessment date, discontinuation of ibrutinib, or death prior to OI as competing risks. The cumulative incidence of OI was estimated and the Fine and Gray regression models were used to examine the association between patient characteristics and risk of OI. Covariates with significance level of p<0.20 from univariable analyses were further evaluated in a multivariable analysis using a stepwise selection procedure, retaining those with p<0.05 in the final model. RESULTSThe cohort included 566 patients. Median age was 65 (range 23-89) and 70.1% (397/566) were men. The majority of patients had CLL (73.7%, 417/566). Other diagnoses included mantle cell lymphoma (9.9%, 56/566), indolent B-cell malignancies (8.1%, 46/566; 11 Waldenström's Macroglobulinemia, 13 Hairy Cell Leukemia, 15 Follicular Lymphoma, 6 Marginal Zone Lymphoma, and 1 Prolymphocytic Leukemia), and aggressive lymphoma (8.3%, 47/566; 35 diffuse large B-cell or transformed lymphoma and 12 Richter's syndrome). Median number of prior treatments was 3 (range 0-18) and 6.5% (37/566) of patients were treatment naïve. Ibrutinib was prescribed on clinical trial for 80.9% (458/566) of patients with the rest receiving it as standard of care. A second agent was given with ibrutinib in 30.9% (175/566) of cases and was most often a monoclonal antibody (81.7%, 143/175). Use of antiviral prophylaxis was common (78.6%, 445/566) with fewer patients receiving PJP (44.9%, 254/566) or fungal (11.5%, 65/566) prophylaxis. The most utilized prophylactic antifungal agent was fluconazole (70.8%, 46/65). Total ibrutinib exposure for the cohort was 1,225 person-years with a median exposure of 1.98 (range 0.008-6.40) years. Median duration of follow-up was 2.69 (range 0.03-6.40) years. Twenty-three of 566 (4.1%) patients developed an OI at a median of 0.39 (range 0.03-4.33) years after starting ibrutinib. The cumulative incidence of OI was 2.3% (95% CI: 1.3-3.8%) at 0.5 years and increased to 4.7% (95% CI: 3.0-7.0-%) at 5 years. Types of OI and outcomes are detailed in Table 1. Median survival of the entire cohort was not reached. Among 23 OI patients, the median survival after infection was 1.39 years. Univariable analysis revealed ≥3 prior treatments (HR 2.61), diabetes (HR 3.03), pulmonary disease (HR 2.81), chronic kidney disease (HR 2.56), and liver disease (HR 6.42) were associated with an increased risk for OI (p<0.05). In a multivariable analysis ≥3 prior treatments (HR 2.87, 95% CI: 1.12-7.35; p=0.028), diabetes (HR 3.63, 95% CI: 1.50-8.77; p=0.004), and liver disease (HR 7.53, 95% CI: 2.14-26.49; p=0.002) retained independent association with OI development. CONCLUSIONSThe cumulative incidence of OI during ibrutinib treatment was low (4.7% at 5 years) and the most common type was invasive fungal (61%) with no PJP cases. Three or greater prior treatments, diabetes, and liver disease were independently associated with risk for OI. [Display omitted] DisclosuresByrd:Janssen: Research Funding; The Ohio State University: Patents & Royalties: OSU-2S; Genentech: Research Funding; Acerta Pharma: Research Funding; Pharmacyclics: Research Funding.

Ibrutinib efficacy and tolerability in patients with relapsed chronic lymphocytic leukemia following allogeneic HCT

AbstractIbrutinib, a potent and irreversible small-molecule inhibitor of both Bruton's tyrosine kinase and interleukin-2 inducible kinase (ITK), has been used to treat relapsed/refractory chronic lymphocytic leukemia (CLL) with prolongation of progression-free and overall survival. Here, we present 27 patients with relapsed CLL following allogeneic hematopoietic cell transplant (HCT) who subsequently received ibrutinib salvage therapy. Sixteen of these patients were part of multi-institutional clinical trials and achieved an overall response rate of 87.5%. An additional 11 patients were treated at Stanford University following US Food and Drug Administration approval of ibrutinib; 7 (64%) achieved a complete response, and 3 (27%) achieved a partial response. Of the 9 patients treated at Stanford who had mixed chimerism–associated CLL relapse, 4 (44%) converted to full donor chimerism following ibrutinib initiation, in association with disease response. Four of 11 (36%) patients evaluated by ClonoSeq achieved minimal residual disease negativity with CLL <1/10 000 white blood cells, which persisted even after ibrutinib was discontinued, in 1 case even after 26 months. None of the 27 patients developed graft-versus-host-disease (GVHD) following ibrutinib initiation. We postulate that ibrutinib augments the graft-versus-leukemia (GVL) benefit through a T-cell–mediated effect, most likely due to ITK inhibition. To investigate the immune modulatory effects of ibrutinib, we completed comprehensive immune phenotype characterization of peripheral B and T cells from treated patients. Our results show that ibrutinib selectively targets pre–germinal B cells and depletes Th2 helper cells. Furthermore, these effects persisted after drug discontinuation. In total, our results provide evidence that ibrutinib effectively augments GVL without causing GVHD.

Ibrutinib Treatment of Relapsed CLL Following Allogeneic Transplantation: Sustained Disease Response and Promising Donor Immune Modulation

Abstract Background: Treatment of relapsed chronic lymphocytic leukemia (CLL) with ibrutinib results in high rates of progression-free and overall survival. Ibrutinib, an irreversible inhibitor of Bruton’s tyrosine kinase (BTK), is FDA-approved for use in relapsed CLL. Ibrutinib may also modulate donor T cell alloimmunity via inhibition of interleukin-2-inducible kinase (ITK). Here we report the effects of ibrutinib salvage therapy in 5 CLL patients who relapsed following allogeneic hematopoietic cell transplantation (allo-HCT). In addition to minimal residual disease (MRD) response measurements, we also assessed donor T cell chimerism and donor B cell immune reconstitution following ibrutinib therapy. Methods: Five patients with high-risk CLL relapsed 1-8.5 yrs following allo-HCT. Four patients had never achieved donor CD3 T cell chimerism >95% following reduced-intensity transplant. Ibrutinib 420mg daily was started 1 mo-2 yrs after clinical relapse. Four of the 5 patients remain on ibrutinib with treatment courses ranging from 3-17 mos. CLL MRD was measured by IgH high-throughput sequencing (HTS) using the ClonoSIGHTTM test (Sequenta, Inc.), which has the sensitivity to detect 1 CLL clone per million leukocytes. Lymph node (LN) size was assessed by CT scan and reported as the sum of the products of the LN diameters (SPD). Donor B cell reconstitution was determined by IgH HTS quantification of total IgH molecules and unique IgH clonotypes. Results: Lymphocytosis was observed in all 5 patients following initiation of ibrutinib treatment, consistent with previous reports. In 2 patients who received >1 yr of ibrutinib treatment, lymphocytosis peaked at 3 wks and 8 wks after initiation of treatment and slowly declined thereafter, fully resolving within 1 yr (Fig 1A). All 4 patients with pathologic lymphadenopathy prior to treatment experienced dramatic LN reduction (Fig 1B; 68% average reduction in LN size after 3 mos on ibrutinib). The longest duration of follow-up is reported for patient SPN 3975, who had a 17p deletion and received ibrutinib for 39 mos. Treatment was discontinued after CLL MRD became undetectable by ClonoSIGHT (Fig 1C). Evidence of donor T cell immune modulation included achievement of full donor CD3 chimerism after 1 yr and resolution of oral and skin chronic graft-versus-host disease (GVHD) after 6 mos. Although this patient has been off ibrutinib for >8 mos, full donor chimerism persists and CLL MRD remains undetectable (Fig 1C). Before ibrutinib treatment, donor B cells (excluding the patient’s CLL clone) accounted for 1% of PBMC (Fig 1D). Furthermore, recovering B cells have diverse, low frequency IgH clonotypes (Fig 1E). Together, our findings show rapid, sustained, and diverse immune reconstitution without CLL recurrence following ibrutinib discontinuation. Conclusions: Ibrutinib provides effective salvage therapy for CLL relapse following allo-HCT. Post-transplant CLL relapse is often extra-nodal and our experience shows ibrutinib is effective in clearing both nodal and extra-nodal disease. Here we present one patient who stopped therapy after achieving MRD negativity and maintains undetectable disease 8 mos following ibrutinib discontinuation. Ibrutinib treatment demonstrates promising donor immune modulation by promoting full donor chimerism and resolution of chronic GVHD. Our five patient experience supports using ibrutinib in relapsed CLL patients following allo-HCT. Clinical trials are needed to determine the best duration of ibrutinib therapy following post-allo-HCT relapse, chronic GVHD treatment efficacy, and the role of ibrutinib maintenance following allo-HCT. Download : Download high-res image (120KB) Download : Download full-size image Figure 1 . (A) Percent change in absolute lymphocytic count (ALC) for 2 patients who received ibrutinib treatment for >1 yr. SPN = Stanford Patient Number. (B) Percent reduction in LN size, as reported by the sum of the product of LN diameters (SPD) for 4 patients following initiation of ibrutinib. (C) CLL MRD (reported as a percentage of WBCs) and blood donor CD3 T cell levels shown for patient SPN 3975. (D) B cells (excluding the CLL clone) as percent of total PBMC for patient SPN 3975 as measured by IgH HTS. (E) Total IgH molecules and unique IgH clone counts for patient SPN 3975 at different time points (D=day) post allo-HCT. Disclosures Kong: Sequenta, Inc.: Employment, Equity Ownership. Klinger: Sequenta, Inc.: Employment, Equity Ownership. Faham: Sequenta, Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees. Coutre: Pharmacyclics, Inc.: Consultancy, Research Funding. Miklos: Sequenta, Inc.: Research Funding.

Ibrutinib Treatment of Relapsed CLL Following Allogeneic Transplantation: Sustained Disease Response and Promising Donor Immune Modulation

Background: Treatment of relapsed chronic lymphocytic leukemia (CLL) with ibrutinib results in high rates of progression-free and overall survival. Ibrutinib, an irreversible inhibitor of Bruton’s tyrosine kinase (BTK), is FDA-approved for use in relapsed CLL. Ibrutinib may also modulate donor T cell alloimmunity via inhibition of interleukin-2-inducible kinase (ITK). Here we report the effects of ibrutinib salvage therapy in 5 CLL patients who relapsed following allogeneic hematopoietic cell transplantation (allo-HCT). In addition to minimal residual disease (MRD) response measurements, we also assessed donor T cell chimerism and donor B cell immune reconstitution following ibrutinib therapy.Methods: Five patients with high-risk CLL relapsed 1-8.5 yrs following allo-HCT. Four patients had never achieved donor CD3 T cell chimerism >95% following reduced-intensity transplant. Ibrutinib 420mg daily was started 1 mo-2 yrs after clinical relapse. Four of the 5 patients remain on ibrutinib with treatment courses ranging from 3-17 mos. CLL MRD was measured by IgH high-throughput sequencing (HTS) using the ClonoSIGHTTM test (Sequenta, Inc.), which has the sensitivity to detect 1 CLL clone per million leukocytes. Lymph node (LN) size was assessed by CT scan and reported as the sum of the products of the LN diameters (SPD). Donor B cell reconstitution was determined by IgH HTS quantification of total IgH molecules and unique IgH clonotypes.Results: Lymphocytosis was observed in all 5 patients following initiation of ibrutinib treatment, consistent with previous reports. In 2 patients who received >1 yr of ibrutinib treatment, lymphocytosis peaked at 3 wks and 8 wks after initiation of treatment and slowly declined thereafter, fully resolving within 1 yr (Fig 1A). All 4 patients with pathologic lymphadenopathy prior to treatment experienced dramatic LN reduction (Fig 1B; 68% average reduction in LN size after 3 mos on ibrutinib). The longest duration of follow-up is reported for patient SPN 3975, who had a 17p deletion and received ibrutinib for 39 mos. Treatment was discontinued after CLL MRD became undetectable by ClonoSIGHT (Fig 1C). Evidence of donor T cell immune modulation included achievement of full donor CD3 chimerism after 1 yr and resolution of oral and skin chronic graft-versus-host disease (GVHD) after 6 mos. Although this patient has been off ibrutinib for >8 mos, full donor chimerism persists and CLL MRD remains undetectable (Fig 1C). Before ibrutinib treatment, donor B cells (excluding the patient’s CLL clone) accounted for <0.2% of total PBMC as determined by IgH HTS. Following discontinuation of ibrutinib, the percentage of donor B cells increased within 6 months, and now comprises >1% of PBMC (Fig 1D). Furthermore, recovering B cells have diverse, low frequency IgH clonotypes (Fig 1E). Together, our findings show rapid, sustained, and diverse immune reconstitution without CLL recurrence following ibrutinib discontinuation.Conclusions: Ibrutinib provides effective salvage therapy for CLL relapse following allo-HCT. Post-transplant CLL relapse is often extra-nodal and our experience shows ibrutinib is effective in clearing both nodal and extra-nodal disease. Here we present one patient who stopped therapy after achieving MRD negativity and maintains undetectable disease 8 mos following ibrutinib discontinuation. Ibrutinib treatment demonstrates promising donor immune modulation by promoting full donor chimerism and resolution of chronic GVHD. Our five patient experience supports using ibrutinib in relapsed CLL patients following allo-HCT. Clinical trials are needed to determine the best duration of ibrutinib therapy following post-allo-HCT relapse, chronic GVHD treatment efficacy, and the role of ibrutinib maintenance following allo-HCT. [Display omitted] DisclosuresKong:Sequenta, Inc.: Employment, Equity Ownership. Klinger:Sequenta, Inc.: Employment, Equity Ownership. Faham:Sequenta, Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees. Coutre:Pharmacyclics, Inc.: Consultancy, Research Funding. Miklos:Sequenta, Inc.: Research Funding.

Ibrutinib is an irreversible molecular inhibitor of ITK driving a Th1-selective pressure in T lymphocytes

AbstractGiven its critical role in T-cell signaling, interleukin-2–inducible kinase (ITK) is an appealing therapeutic target that can contribute to the pathogenesis of certain infectious, autoimmune, and neoplastic diseases. Ablation of ITK subverts Th2 immunity, thereby potentiating Th1-based immune responses. While small-molecule ITK inhibitors have been identified, none have demonstrated clinical utility. Ibrutinib is a confirmed irreversible inhibitor of Bruton tyrosine kinase (BTK) with outstanding clinical activity and tolerability in B-cell malignancies. Significant homology between BTK and ITK alongside in silico docking studies support ibrutinib as an immunomodulatory inhibitor of both ITK and BTK. Our comprehensive molecular and phenotypic analysis confirms ITK as an irreversible T-cell target of ibrutinib. Using ibrutinib clinical trial samples along with well-characterized neoplastic (chronic lymphocytic leukemia), parasitic infection (Leishmania major), and infectious disease (Listeria monocytogenes) models, we establish ibrutinib as a clinically relevant and physiologically potent ITK inhibitor with broad therapeutic utility. This trial was registered at www.clinicaltrials.gov as #NCT01105247 and #NCT01217749.

Ibrutinib Also Inhibits ITK

Abstract The Bruton tyrosine kinase inhibitor ibrutinib targets interleukin-2 inducible kinase (ITK) in T cells.

Abstract 492: Ibrutinib inhibits Interleukin-2 inducible kinase, driving a Th1 selective pressure in human leukemia patients that serves to alleviate tumor-induced immunosupression.

Abstract Interleukin-2 Inducible Kinase (ITK) is an appealing therapeutic target given its critical role in polarizing T-cell immunity against various infectious, autoimmune, and neoplastic diseases. ITK activity promotes Th2 immunity, thereby subverting healthy Th1-based immune surveillance. Th2 CD4 T-cells depend on ITK for activation, whereas Th1 and CD8 T-cells have compensatory resting lymphocyte kinase (RLK) that conducts T-cell receptor activation in the absence of ITK. Similar to many other tumors, chronic lymphocytic leukemia (CLL) directs an aberrant Th2 bias that drives immune evasion, promotes a supportive microenvironment, and cripples adaptive immunity. In CLL, this immune suppression leads to severe infections which are a leading cause of death. Although ITK inhibitors have the promise of alleviating tumor-induced immune suppression, to date no clinically viable ITK inhibitor exists. Ibrutinib is an irreversible inhibitor of Bruton's tyrosine kinase (BTK) with outstanding activity and tolerability in B-cell malignancies. The striking homology between BTK and ITK combined with our in silico docking studies and in vitro kinase inhibition profiles led us to identify ibrutinib as the first clinically viable irreversible ITK inhibitor. We further confirmed both molecular and functional outcomes using Jurkat T-cells and in vitro polarized Th1 and Th2 CD4 T-cells. We found that mutation of the ITK-Cys442 covalent binding residue for ibrutinib alleviated molecular inhibition. We also demonstrated that Th1 and CD8 T-cell restricted expression of RLK provides a compensatory platform for T-cell activation, offering a molecular explanation for the selective outgrowth of cytotoxic Th1-biased immunity. This effect was confirmed using T-cells directly derived from CLL patients. To clearly demonstrate this effect in vivo, we utilized the Leishmania major model of Th2-mediated infection. Ibrutinib enhanced resistance to the parasite by eliciting robust Th1 immunity. To demonstrate a direct clinical relevance in the setting of CLL we utilized a novel listeriosis/leukemia mouse model. In this model, we observed complete recovery of functional immunity, with all ibrutinib-treated mice surviving a potentially lethal Listeria monocytogenes infection. We further confirmed irreversible binding of ITK in patients currently receiving ibrutinib as part of a clinical trial. Finally, we found that ibrutinib inhibited phosphorlyation of ITK's direct downstream target PLCγ1 in CD4 T-cells. Together, our results provide novel molecular insights into the mechanism of action of ibrutinib in the context of Th2-biased immunosuppressive leukemia. We also postulate that ibrutinib's irreversible ITK inhibitory effects may prove beneficial in a number of other autoimmune, inflammatory, parasitic, and viral diseases. Citation Format: Jason A. Dubovsky, Kyle A. Beckwith, Gayathri Natarajan, Jennifer A. Woyach, Samantha Jaglowski, Joshua Hessler, Ta-Ming Liu, Betty Y. Chang, Karilyn M. Larkin, Matthew R. Stefanovski, Frank W. Frissora, Lisa L. Smith, Kelly A. Smucker, Joseph M. Flynn, Jeffrey A. Jones, Leslie A. Andritsos, Kami Maddocks, Amy M. Lehman, Richard Furman, Jeff Sharman, Anjali Mishra, Michael A. Caligiuri, Abhay R. Satoskar, Joseph J. Buggy, Natarajan Muthusamy, Amy J. Johnson, John C. Byrd. Ibrutinib inhibits Interleukin-2 inducible kinase, driving a Th1 selective pressure in human leukemia patients that serves to alleviate tumor-induced immunosupression. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 492. doi:10.1158/1538-7445.AM2013-492