The combination of the BCL2 inhibitor venetoclax plus obinutuzumab was more effective in the treatment of older medically ill patients with untreated chronic lymphocytic leukemia than was ...chlorambucil plus obinutuzumab. Progression-free survival at 2 years was 88% with venetoclax and 64% with chlorambucil.
Activation of the ER stress response is associated with malignant progression of B cell chronic lymphocytic leukemia (CLL). We developed a murine CLL model that lacks the ER stress-associated ...transcription factor XBP-1 in B cells and found that XBP-1 deficiency decelerates malignant progression of CLL-associated disease. XBP-1 deficiency resulted in acquisition of phenotypes that are disadvantageous for leukemic cell survival, including compromised BCR signaling capability and increased surface expression of sphingosine-1-phosphate receptor 1 (S1P1). Because XBP-1 expression requires the RNase activity of the ER transmembrane receptor IRE-1, we developed a potent IRE-1 RNase inhibitor through chemical synthesis and modified the structure to facilitate entry into cells to target the IRE-1/XBP-1 pathway. Treatment of CLL cells with this inhibitor (B-I09) mimicked XBP-1 deficiency, including upregulation of IRE-1 expression and compromised BCR signaling. Moreover, B-I09 treatment did not affect the transport of secretory and integral membrane-bound proteins. Administration of B-I09 to CLL tumor-bearing mice suppressed leukemic progression by inducing apoptosis and did not cause systemic toxicity. Additionally, B-I09 and ibrutinib, an FDA-approved BTK inhibitor, synergized to induce apoptosis in B cell leukemia, lymphoma, and multiple myeloma. These data indicate that targeting XBP-1 has potential as a treatment strategy, not only for multiple myeloma, but also for mature B cell leukemia and lymphoma.
Histone deacetylases (HDACs) are involved in diverse cellular regulatory mechanisms including non-canonical functions outside the chromatin environment. Several publications have demonstrated that ...selective HDAC inhibitors (HDACi) can influence tumor immunogenicity and the functional activity of specific immune cells. In particular, the selective inhibition of HDAC6 has been reported to decrease tumor growth in several malignancies. However, there is still no clarity about the cellular components mediating this effect. In this study, we evaluated the HDAC6i Nexturastat A as a priming agent to facilitate the transition of the tumor microenvironment from "cold" to "hot", and potentially augment immune check-point blockade therapies. This combination modality demonstrated to significantly reduce tumor growth in syngeneic melanoma tumor models. Additionally, we observed a complete neutralization of the up-regulation of PD-L1 and other immunosuppressive pathways induced by the treatment with anti-PD-1 blockade. This combination also showed profound changes in the tumor microenvironment such as enhanced infiltration of immune cells, increased central and effector T cell memory, and a significant reduction of pro-tumorigenic M2 macrophages. The evaluation of individual components of the tumor microenvironment suggested that the in vivo anti-tumor activity of HDAC6i is mediated by its effect on tumor cells and tumor-associated macrophages, and not directly over T cells. Overall, our results indicate that selective HDAC6i could be used as immunological priming agents to sensitize immunologically "cold" tumors and subsequently improve ongoing immune check-point blockade therapies.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Expression of HDAC11 may be involved in myeloid cell biology.
Epigenetic changes in chromatin structure have been recently associated with the deregulated expression of critical genes in normal and ...malignant processes. HDAC11, the newest member of the HDAC family of enzymes, functions as a negative regulator of IL‐10 expression in APCs, as previously described by our lab. However, at the present time, its role in other hematopoietic cells, specifically in neutrophils, has not been fully explored. In this report, for the first time, we present a novel physiologic role for HDAC11 as a multifaceted regulator of neutrophils. Thus far, we have been able to demonstrate a lineage‐restricted overexpression of HDAC11 in neutrophils and committed neutrophil precursors (promyelocytes). Additionally, we show that HDAC11 appears to associate with the transcription machinery, possibly regulating the expression of inflammatory and migratory genes in neutrophils. Given the prevalence of neutrophils in the peripheral circulation and their central role in the first line of defense, our results highlight a unique and novel role for HDAC11. With the consideration of the emergence of new, selective HDAC11 inhibitors, we believe that our findings will have significant implications in a wide range of diseases spanning malignancies, autoimmunity, and inflammation.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Ponatinib, the only third‐generation pan‐BCR::ABL1 inhibitor with activity against all known BCR::ABL1 mutations including T315I, has demonstrated deep and durable responses in patients with ...chronic‐phase chronic myeloid leukemia (CP‐CML) resistant to prior second‐generation (2G) TKI treatment. We present efficacy and safety outcomes from the Ponatinib Philadelphia chromosome–positive acute lymphoblastic leukemia (Ph+ ALL) and CML Evaluation (PACE) and Optimizing Ponatinib Treatment in CP‐CML (OPTIC) trials for this patient population. PACE (NCT01207440) evaluated ponatinib 45 mg/day in CML patients with resistance to prior TKI or T315I. In OPTIC (NCT02467270), patients with CP‐CML and resistance to ≥2 prior TKIs or T315I receiving 45 or 30 mg/day reduced their doses to 15 mg/day upon achieving ≤1% BCR::ABL1IS or received 15 mg/day continuously. Efficacy and safety outcomes from patients with CP‐CML treated with ≥1 2G TKI (PACE, n = 257) and OPTIC (n = 93), 45‐mg starting dose cohort, were analyzed for BCR::ABL1IS response rates, overall survival (OS), progression‐free survival (PFS), and safety. By 24 months, the percentages of patients with ≤1% BCR::ABL1IS response, PFS, and OS were 46%, 68%, and 85%, respectively, in PACE and 57%, 80%, and 91%, respectively, in OPTIC. Serious treatment‐emergent adverse events and serious treatment‐emergent arterial occlusive event rates were 63% and 18% in PACE and 34% and 4% in OPTIC. Ponatinib shows high response rates and robust survival outcomes in patients whose disease failed prior to 2G TKIs, including patients with T315I mutation. The response‐based dosing in OPTIC led to improved safety and similar efficacy outcomes compared with PACE.
Analysis of the largest CP‐CML population in a post‐second‐generation TKI setting (N = 350)
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Background
Fatigue is a common and disabling side effect of targeted therapies such as tyrosine kinase inhibitors (TKIs) used to treat chronic myeloid leukemia (CML). The goal of the current study ...was to conduct a pilot randomized trial of the first cognitive behavioral intervention developed for fatigue due to targeted therapy.
Methods
Patients with CML treated with a TKI who were reporting moderate to severe fatigue were recruited and randomized 2:1 to cognitive behavioral therapy for targeted therapy–related fatigue (CBT‐TTF) delivered via FaceTime for the iPad or to a waitlist control (WLC) group. The outcomes were acceptability, feasibility, and preliminary efficacy for fatigue (Functional Assessment of Chronic Illness Therapy–Fatigue; primary outcome) and quality of life (Functional Assessment of Cancer Therapy–General; secondary outcome). Participants were assessed before randomization and after treatment (ie, approximately 18 weeks later).
Results
A total of 44 patients (mean age, 55 years; 48% female) were assigned to CBT‐TTF (n = 29) or WLC (n = 15). The study participation rate was 59%. Among the patients assigned to CBT‐TTF, 79% completed the intervention. Intent‐to‐treat analyses indicated that patients assigned to CBT‐TTF demonstrated greater improvements in fatigue (d = 1.06; P < .001) and overall quality of life (d = 1.15; P = .005) than those assigned to WLC. More patients randomized to CBT‐TTF than WLC demonstrated clinically significant improvements in fatigue (85% vs 29%) and quality of life (88% vs 54%; P values ≤ .016).
Conclusions
CBT‐TTF displays preliminary efficacy in improving fatigue and quality of life among fatigued patients with CML treated with TKIs. The findings suggest that a larger randomized study is warranted.
This pilot randomized trial examines a FaceTime‐delivered cognitive behavioral intervention for fatigue in fatigued patients with chronic myeloid leukemia treated with a tyrosine kinase inhibitor in comparison with a waitlist control. The results show large improvements in fatigue and quality of life.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Myeloid‐derived suppressor cells (MDSCs) constitute a heterogeneous population of immature myeloid cells derived from bone marrow and negatively regulate both innate and adaptive immunity in the ...tumor microenvironment. Previously we have demonstrated that MDSCs lacking histone deacetylase 11 (HDAC11) displayed an increased suppressive activity against CD8+ T‐cells. However, the mechanisms of HDAC11 that contribute to the suppressive function of MDSCs remain unclear. Here, we show that arginase activity and NO production is significantly higher in HDAC11 knockout MDSCs when compared with wild‐type (WT) controls. In the absence of HDAC11, elevated arginase level and enzymatic activity were observed preferentially in the tumor‐infiltrated granulocytic MDSCs, whereas iNOS expression and NO production were increased in the tumor‐infiltrated monocytic MDSCs. Of note and for the first time, we demonstrated an association between the elevated expression of immunosuppressive molecules with up‐regulation of the transcription factor C/EBPβ in MDSCs lacking HDAC11. Interestingly, the highest expression of C/EBPβ was observed among CD11b+ Gr‐1+ MDSCs isolated from tumor‐bearing mice. The additional demonstration that HDAC11 is recruited to the promoter region of C/EBPβ in WT MDSCs suggests a novel molecular mechanism by which HDAC11 influence the expression of immunosuppressive molecules in MDSCs through regulation of C/EBPβ gene expression.
Graphical
HDAC11 negatively regulates MDSCs function through down‐regulation of C/EBPβ.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Among Bruton's tyrosine kinase inhibitors, acalabrutinib has greater selectivity than ibrutinib, which we hypothesized would improve continuous therapy tolerability. We conducted an open-label, ...randomized, noninferiority, phase III trial comparing acalabrutinib and ibrutinib in patients with chronic lymphocytic leukemia (CLL).
Patients with previously treated CLL with centrally confirmed del(17)(p13.1) or del(11)(q22.3) were randomly assigned to oral acalabrutinib 100 mg twice daily or ibrutinib 420 mg once daily until progression or unacceptable toxicity. The primary end point was independent review committee-assessed noninferiority of progression-free survival (PFS).
Overall, 533 patients (acalabrutinib, n = 268; ibrutinib, n = 265) were randomly assigned. At the data cutoff, 124 (46.3%) acalabrutinib patients and 109 (41.1%) ibrutinib patients remained on treatment. After a median follow-up of 40.9 months, acalabrutinib was determined to be noninferior to ibrutinib with a median PFS of 38.4 months in both arms (95% CI acalabrutinib, 33.0 to 38.6 and ibrutinib, 33.0 to 41.6; hazard ratio: 1.00; 95% CI, 0.79 to 1.27). All-grade atrial fibrillation/atrial flutter incidence was significantly lower with acalabrutinib versus ibrutinib (9.4%
16.0%;
= .02); among other selected secondary end points, grade 3 or higher infections (30.8%
30.0%) and Richter transformations (3.8%
4.9%) were comparable between groups and median overall survival was not reached in either arm (hazard ratio, 0.82; 95% CI, 0.59 to 1.15), with 63 (23.5%) deaths with acalabrutinib and 73 (27.5%) with ibrutinib. Treatment discontinuations because of adverse events occurred in 14.7% of acalabrutinib-treated patients and 21.3% of ibrutinib-treated patients.
In this first direct comparison of less versus more selective Bruton's tyrosine kinase inhibitors in CLL, acalabrutinib demonstrated noninferior PFS with fewer cardiovascular adverse events.
Venetoclax-based therapy is a standard-of-care option in first-line and relapsed/refractory chronic lymphocytic leukemia (CLL). Patient management following venetoclax discontinuation remains ...nonstandard and poorly understood.
To address this, we conducted a large international study to identify a cohort of 326 patients who discontinued venetoclax and have been subsequently treated. Coprimary endpoints were overall response rate (ORR) and progression-free survival for the post-venetoclax treatments stratified by treatment type Bruton's tyrosine kinase inhibitor (BTKi), PI3K inhibitor (PI3Ki), and cellular therapies.
We identified patients with CLL who discontinued venetoclax in the first-line (4%) and relapsed/refractory settings (96%). Patients received a median of three therapies prior to venetoclax; 40% were BTKi naïve (
= 130), and 81% were idelalisib naïve (
= 263). ORR to BTKi was 84% (
= 44) in BTKi-naïve patients versus 54% (
= 30) in BTKi-exposed patients. We demonstrate therapy selection following venetoclax requires prior novel agent exposure consideration and discontinuation reasons.
For BTKi-naïve patients, selection of covalently binding BTKis results in high ORR and durable remissions. For BTKi-exposed patients, covalent BTK inhibition is not effective in the setting of BTKi resistance. PI3Kis following venetoclax do not appear to result in durable remissions. We conclude that BTKi in naïve or previously responsive patients and cellular therapies following venetoclax may be the most effective strategies.
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