Boysen, Justin

SummaryThe effects of ibrutinib on the natural history of autoimmune cytopenias (AIC) among chronic lymphocytic leukaemia (CLL) patients treated in routine clinical practice require further investigation. Using the Mayo Clinical CLL Database, 193 CLL patients treated with ibrutinib between November 2013 and January 2017 outside the context of a clinical trial were identified; complete review of their medical records was performed for details of past history of AIC and treatment‐emergent AIC. We identified 29/193 (15%) patients with history of AIC prior to ibrutinib start. Of 12 patients requiring AIC therapy at ibrutinib start, 8 (67%) were able to discontinue or de‐escalate AIC treatment, and no patient had worsening of their AIC after initiating ibrutinib. Eleven (6%) patients developed treatment‐emergent AIC after a median of 59 (range, 6–319) days following the initiation of ibrutinib, 7 of whom (64%) were able to continue ibrutinib. Overall and event‐free survival from time of ibrutinib start were not significantly different between patients with history of AIC and those with no history of AIC. Treatment‐emergent AIC were seen exclusively in patients with unmutated IGHV and were associated with a shorter EFS. These results suggest a low rate of treatment‐emergent AIC and improvement in patients with existing AIC.

Background Platelet microparticles (PMPs) and their abundance in the blood are a prognostic biomarker in thrombotic disorders and cancer. Nanoscale flow cytometry (nFC) is ideal for high-throughput analysis of PMPs but these clinical assays have not been developed previously. Objective This article demonstrates that nFC is a suitable technology to enumerate PMPs present in plasma samples in a clinical setting. Materials and Methods nFC was performed using the Apogee A50-Micro instrument. Instrument settings and acquisition parameters were developed with the use of fluorescent beads and plasma samples. Sample preparation and handling was also optimized. Results nFC allows for linear detection of particles between approximately 200 and 1,000 nm based on calibration beads and was dependent on dilution factor and flow rate. Linearity in event analysis as samples became more diluted was lost when events approximately 100 nm were gated while linearity was maintained despite dilution of sample in events larger than 200 nm in diameter. Higher flow rates lead to an under-estimation of events analysed per microlitre of analyte and this was more pronounced when plasma samples were not diluted more than 1/20×. Conclusion nFC offers multi-parametric analysis of PMPs when optimal calibration of acquisition and sample processing settings is performed. Analysis of plasmas from metastatic prostate cancer patients and leukaemia patients revealed that PMP levels were larger than 100 nm and were equally abundant in patients that responded to or failed androgen deprivation therapy or between patients representing different stages of leukaemia.

Akt is a downstream target of B cell receptor signaling and is a central regulator of CLL cell survival. We aim to investigate the safety and efficacy of the Akt inhibitor MK‐2206 in combination with bendamustine and rituximab (BR) in relapsed and/or refractory CLL in a phase I/II study. A standard phase I design was used with cohorts of three plus three patients to determine the maximum tolerated dose (MTD) of MK‐2206 in combination with BR in relapsed CLL. Single‐agent MK‐2206 (weekly dosed) was administered one‐week in advance before BR on cycle 1 and subsequently was given with BR at the same time for cycle 2‐6. Phase II employed the MTD of MK‐2206 with BR to evaluate safety and efficacy of this study combination. Thirteen relapsed/refractory CLL were treated for maximal 6‐cycle of therapy. The maximum tolerated dose of MK‐2206 was 90 mg by mouth once weekly. The most common grade 3/4 adverse events were neutropenia (46%), febrile neutropenia (23%), rash (15%), diarrhea (15%), and thrombocytopenia (15%). Overall response rate was 92% with a median progression free survival and treatment free survival of 16 and 24 months, respectively. Five patients (38%) achieved complete remission or complete remission with incomplete count recovery, two of whom were MRD negative. The efficacy and tolerability of this combination indicates that Akt inhibition combined with chemoimmunotherapy is a promising novel treatment combination in CLL and deserves further prospective clinical trial.

Abstract Purpose: B-cell chronic lymphocytic leukemia (CLL) is an incurable disease despite aggressive therapeutic approaches. We previously found that Axl receptor tyrosine kinase (RTK) plays a critical role in CLL B-cell survival. Here, we explored the possibility of using a high-affinity Axl inhibitor as a single agent or in combination with Bruton's tyrosine kinase (BTK) inhibitors for future clinical trial to treat patients with CLL. Experimental Design: Expression/activation status of other members of the TAM (e.g., Tyro3, Axl, and MER) family of RTKs in CLL B cells was evaluated. Cells were treated with a high-affinity orally bioavailable Axl inhibitor TP-0903 with or without the presence of CLL bone marrow stromal cells (BMSCs). Inhibitory effects of TP-0903 on the Axl signaling pathway were also evaluated in CLL B cells. Finally, cells were exposed to TP-0903 in combination with BTK inhibitors to determine any synergistic/additive effects of the combination. Results: CLL B cells overexpress Tyro3, but not MER. Of interest, Tyro3 remains as constitutively phosphorylated and forms a complex with Axl in CLL B cells. TP-0903 induces massive apoptosis in CLL B cells with LD50 values of nanomolar ranges. Importantly, CLL BMSCs could not protect the leukemic B cells from TP-0903–induced apoptosis. A marked reduction of the antiapoptotic proteins Mcl-1, Bcl-2, and XIAP and upregulation of the proapoptotic protein BIM in CLL B cells was detected as a result of Axl inhibition. Finally, combination of TP-0903 with BTK inhibitors augments CLL B-cell apoptosis. Conclusions: Administration of TP-0903 either as a single agent or in combination with BTK inhibitors may be effective in treating patients with CLL. Clin Cancer Res; 21(9); 2115–26. ©2015 AACR.