Project description:Ibrutinib, a bruton's tyrosine kinase inhibitor, was shown to have high response rates in mantle cell lymphoma (MCL), an aggressive B-cell lymphoma. However, emergence of ibrutinib resistance (IR) and subsequent fatal progression is of significant clinical concern. By implementing genomics, chemical proteomics and drug screening, we report that enhancer remodeling-mediated transcriptional activation and adaptive signaling changes drive the malignant phenotype of IR. Accordingly, IR MCL cells are vulnerable to inhibition of the transcriptional machinery and especially to inhibition of cyclin-dependent kinase 9 (CDK9). Thus, targeting transcriptional activation offers a novel strategy to prevent the emergence of IR and overcome IR via impeding IR-associated cellular signaling reprogramming in MCL. In addition, our ex-vivo microfluidic image-based functional drug screen can function not only as new technology platforms for predicting clinical therapeutic response but also, in conjunction with genomic profiling in primary MCL samples, identify the molecular vulnerabilities for drug resistance evolution, providing insight into the underlying IR mechanisms for MCL and other B-cell malignancies
Project description:Ibrutinib, a bruton's tyrosine kinase (BTK) inhibitor, provokes robust clinical responses in aggressive mantle cell lymphoma (MCL), yet many patients relapse with lethal Ibrutinib-resistant (IR) disease. Here, using genomic, chemical proteomic, and drug screen profiling, we report that enhancer remodeling-mediated transcriptional activation and adaptive signaling changes drive the aggressive phenotypes of IR. Accordingly, IR MCL cells are vulnerable to inhibitors of the transcriptional machinery and especially so to inhibitors of cyclin-dependent kinase 9 (CDK9), the catalytic subunit of the positive transcription elongation factor b (P-TEFb) of RNA polymerase II (RNAPII). Further, CDK9 inhibition disables reprogrammed signaling circuits and prevents the emergence of IR in MCL. Finally, and importantly, we find that a robust and facile ex vivo image-based functional drug screening platform can predict clinical therapeutic responses of IR MCL and identify vulnerabilities that can be targeted to disable the evolution of IR.
Project description:Ibrutinib, a bruton's tyrosine kinase inhibitor, was shown to have high response rates in mantle cell lymphoma (MCL), an aggressive B-cell lymphoma. However, emergence of ibrutinib resistance (IR) and subsequent fatal progression is of significant clinical concern. By implementing genomics, chemical proteomics and drug screening, we report that enhancer remodeling-mediated transcriptional activation and adaptive signaling changes drive the malignant phenotype of IR. Accordingly, IR MCL cells are vulnerable to inhibition of the transcriptional machinery and especially to inhibition of cyclin-dependent kinase 9 (CDK9). Thus, targeting transcriptional activation offers a novel strategy to prevent the emergence of IR and overcome IR via impeding IR-associated cellular signaling reprogramming in MCL. In addition, our ex-vivo microfluidic image-based functional drug screen can function not only as new technology platforms for predicting clinical therapeutic response but also, in conjunction with genomic profiling in primary MCL samples, identify the molecular vulnerabilities for drug resistance evolution, providing insight into the underlying IR mechanisms for MCL and other B-cell malignancies
Project description:Ibrutinib, a bruton's tyrosine kinase inhibitor, was shown to have high response rates in mantle cell lymphoma (MCL), an aggressive B-cell lymphoma. However, emergence of ibrutinib resistance (IR) and subsequent fatal progression is of significant clinical concern. By implementing genomics, chemical proteomics and drug screening, we report that enhancer remodeling-mediated transcriptional activation and adaptive signaling changes drive the malignant phenotype of IR. Accordingly, IR MCL cells are vulnerable to inhibition of the transcriptional machinery and especially to inhibition of cyclin-dependent kinase 9 (CDK9). Thus, targeting transcriptional activation offers a novel strategy to prevent the emergence of IR and overcome IR via impeding IR-associated cellular signaling reprogramming in MCL. In addition, our ex-vivo microfluidic image-based functional drug screen can function not only as new technology platforms for predicting clinical therapeutic response but also, in conjunction with genomic profiling in primary MCL samples, identify the molecular vulnerabilities for drug resistance evolution, providing insight into the underlying IR mechanisms for MCL and other B-cell malignancies
Project description:Altered features of tumor cells acquired across therapy can result in the survival of treatment-resistant clones that may cause minimal residual disease (MRD). Despite the efficacy of ibrutinib in treating relapsed/refractory mantle cell lymphoma, the obstacle of residual cells contributes to relapses of this mature B-cell neoplasm, and the disease remains incurable. RNA-seq analysis of an ibrutinib-sensitive mantle cell lymphoma cell line following ibrutinib incubation of up to 4 d, corroborated our previously postulated resistance mechanism of a metabolic switch to reliance on oxidative phosphorylation (OXPHOS) in surviving cells. Besides, we had shown that treatment-persisting cells were characterized by increased CD52 expression. Therefore, we hypothesized that combining ibrutinib with another agent targeting these potential escape mechanisms could minimize the risk of survival of ibrutinib-resistant cells. Concomitant use of ibrutinib with OXPHOS-inhibitor IACS-010759 increased toxicity compared to ibrutinib alone. Targeting CD52 was even more efficient, as addition of CD52 mAb in combination with human serum following ibrutinib pretreatment led to rapid complement-dependent-cytotoxicity in an ibrutinib-sensitive cell line. In primary mantle cell lymphoma cells, a higher toxic effect with CD52 mAb was obtained, when cells were pretreated with ibrutinib, but only in an ibrutinib-sensitive cohort. Given the challenge of treating multi-resistant mantle cell lymphoma patients, this work highlights the potential use of anti-CD52 therapy as consolidation after ibrutinib treatment in patients who responded to the BTK inhibitor to achieve MRD negativity and prolong progression-free survival.
Project description:Maintenance rituximab in mantle cell lymphoma (MCL) has improved survival and supports exploration of maintenance with novel agents. We evaluated the safety and efficacy of ibrutinib maintenance (I-M) after induction in patients with treatment-naive MCL. Patients with MCL with complete response (CR) or partial response to frontline chemoimmunotherapy ± autologous stem cell transplantation (auto-SCT) received I-M 560 mg daily for up to 4 years. Primary objective was 3-year progression-free survival (PFS) rate from initiation of I-M. Minimal residual disease (MRD) assessments by next-generation sequencing (NGS) on peripheral blood were measured before I-M initiation and at 1, 6, and 18 to 24 months after initiation. Among 36 patients, the median age was 60 years (range, 46-90). For frontline treatment, 18 patients (50%) had consolidation with auto-SCT in CR1 before I-M. At median follow-up of 55.7 months, 17 patients (47%) completed full course I-M (median, 37.5 cycles; range, 2-52). The 3-year PFS and overall survival (OS) rates were 94% and 97%, respectively. With prior auto-SCT, 3-year PFS and OS rates were both 100%. The most common treatment-related adverse event with I-M was infection (n = 31; 86%), typically low grade; the most common grade 3/4 toxicities were hematologic. In 22 patients with MRD assessments, all were MRD negative after induction. Six became MRD positive on I-M, with 2 reverting to MRD-negative status with continued I-M, and all maintain radiographic CR with the exception of 1 with disease progression. I-M is feasible in MCL after frontline chemoimmunotherapy with manageable toxicities although significant. Changes in NGS-MRD were noted in limited patients during maintenance with few progression and survival events. This trial was registered at www.clinicaltrials.gov as #NCT02242097.
Project description:BackgroundBruton's tyrosine kinase (BTK) is a mediator of the B-cell-receptor signaling pathway implicated in the pathogenesis of B-cell cancers. In a phase 1 study, ibrutinib, a BTK inhibitor, showed antitumor activity in several types of non-Hodgkin's lymphoma, including mantle-cell lymphoma.MethodsIn this phase 2 study, we investigated oral ibrutinib, at a daily dose of 560 mg, in 111 patients with relapsed or refractory mantle-cell lymphoma. Patients were enrolled into two groups: those who had previously received at least 2 cycles of bortezomib therapy and those who had received less than 2 complete cycles of bortezomib or had received no prior bortezomib therapy. The primary end point was the overall response rate. Secondary end points were duration of response, progression-free survival, overall survival, and safety.ResultsThe median age was 68 years, and 86% of patients had intermediate-risk or high-risk mantle-cell lymphoma according to clinical prognostic factors. Patients had received a median of three prior therapies. The most common treatment-related adverse events were mild or moderate diarrhea, fatigue, and nausea. Grade 3 or higher hematologic events were infrequent and included neutropenia (in 16% of patients), thrombocytopenia (in 11%), and anemia (in 10%). A response rate of 68% (75 patients) was observed, with a complete response rate of 21% and a partial response rate of 47%; prior treatment with bortezomib had no effect on the response rate. With an estimated median follow-up of 15.3 months, the estimated median response duration was 17.5 months (95% confidence interval [CI], 15.8 to not reached), the estimated median progression-free survival was 13.9 months (95% CI, 7.0 to not reached), and the median overall survival was not reached. The estimated rate of overall survival was 58% at 18 months.ConclusionsIbrutinib shows durable single-agent efficacy in relapsed or refractory mantle-cell lymphoma. (Funded by Pharmacyclics and others; ClinicalTrials.gov number, NCT01236391.)