AI is a viable alternative to high throughput screening: a 318-target study

High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery.

Management and use of healthcare resources in patients with chronic lymphocytic leukemia initiating venetoclax in routine clinical practice

Venetoclax is a first-in-class B-cell lymphoma-2 (BCL-2) inhibitor approved as continuous monotherapy and in combination with rituximab as fixed-treatment duration for relapsed and refractory chronic lymphocytic leukemia (R/R CLL). DEVOTE was a 24-week, multicenter observational study (NCT03310190) evaluating the safety, healthcare resource utilization (HCRU) and health-related quality of life (HRQoL) of patients initiating venetoclax for R/R CLL in Canada. Overall, 89 patients received 1 dose of venetoclax; 80% had prior exposure (42% resistant) to ibrutinib. Biochemical tumor lysis syndrome (TLS) occurred in five patients. We observed differences in hospitalization across Canadian provinces including in patients at low risk for TLS with no clear impact on TLS incidence. Additionally, a rapid and sustained improvement in several domains of HRQoL was observed during venetoclax initiation. Early adoption of venetoclax was mainly for R/R CLL patients with few treatment options; nonetheless, acceptable toxicity and a positive impact on HRQoL were observed.

Canadian evidence-based guideline for treatment of relapsed/refractory chronic lymphocytic leukemia

Following the recent publication of Canadian evidence-based guidelines for frontline treatment of chronic lymphocytic leukemia (CLL), the same group of clinicians developed guidelines for CLL in the relapsed/refractory (R/R) setting. The treatment of R/R CLL has changed significantly in the past few years, with many novel therapeutics available to hematologists across the country. These guidelines aim to standardize the management of CLL in the relapsed/refractory setting, using the best evidence currently available.

Mapping gender and sexual minority representation in cancer research: a scoping review protocol

BACKGROUND

Addressing the risk of people from gender and sexual minority (GSM) groups experiencing inequities throughout the cancer continuum requires a robust evidence base. In this scoping review, we aim to map the literature on cancer outcomes among adults from GSM groups and the factors that influence them along the cancer continuum.

METHODS

This mixed-methods scoping review will follow the approach outlined by JBI. We will systematically search electronic databases for literature in collaboration with a health sciences librarian. Two reviewers will screen titles and abstracts to determine eligibility based on inclusion criteria, and then retrieve full text articles for data extraction. Results will be reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews. Quantitative data will be qualitized through a narrative interpretation and pooled with qualitative data. We will use meta-aggregation to synthesize findings. This protocol was developed in collaboration with GSM patient and public advisors. We will engage people from GSM groups, community organizations and knowledge users in disseminating results.

INTERPRETATION

This review will direct future research efforts by expanding the wider body of research examining cancer disparities across the cancer continuum that GSM groups experience, identifying literature gaps and limitations, and highlighting relevant social determinants of health that influence cancer outcomes for adults from GSM groups.

Clinical Outcomes in a Large Canadian Centralized CLL Clinic Based on Treatment and Molecular Factors over a Decade

FISH cytogenetics, TP53 sequencing, and IGHV mutational status are increasingly used as prognostic and predictive markers in chronic lymphocytic leukemia (CLL), particularly as components of the CLL International Prognostic Index (CLL-IPI) and in directing therapy with novel agents. However, testing outside of clinical trials is not routinely available in Canada. As a centralized CLL clinic at CancerCare Manitoba, we are the first Canadian province to evaluate clinical outcomes and survivorship over a long period of time, incorporating the impact of molecular testing and the CLL-IPI score. We performed a retrospective analysis on 1315 patients diagnosed between 1960 and 2018, followed over a 12-year period, where 411 patients had molecular testing and 233 patients had a known CLL-IPI score at the time of treatment. Overall, 40.3% (n = 530) of patients received treatment, and 47.5% (n = 252) of patients received multiple lines of therapy. High-risk FISH and CLL-IPI (4-10) were associated with higher mortality (HR 2.03, p = 0.001; HR 2.64, p = 0.002), consistent with other studies. Over time, there was an increase in the use of targeted agents in treated patients. The use of Bruton's tyrosine kinase inhibitors improved survival in patients with unmutated IGHV and/or TP53 aberrations (HR 2.20, p = 0.001). The major cause of death in patients who received treatment was treatment/disease-related (32%, n = 42) and secondary malignancies (57%, n = 53) in those who were treatment-naïve. Our data demonstrate the importance of molecular testing in determining survivorship in CLL and underpinning the likely immune differences in outcomes for those treated for CLL.

Elevated expression of interleukin 16 in chronic lymphocytic leukemia is associated with disease burden and abnormal immune microenvironment

Interleukin-16 (IL-16) is a novel biomarker that has been implicated in many cancers as well as inflammatory diseases. In this study, we examined plasma levels of 30 cytokines and chemokines in chronic lymphocytic leukemia (CLL) and monoclonal B cell lymphocytosis (MBL) patients, and examined their association with disease stage, CLL biomarkers and T cell subsets. Interleukin 16 (IL-16) was identified as a relatively uncharacterized cytokine significantly elevated in CLL patients compared to healthy controls and MBL patients. Plasma levels of IL-16 were significantly elevated by Rai stage 0, increased by Rai stage 3-4, correlated strongly with lymphocyte count and were decreased after Ibrutinib treatment. CLL cells expressed IL-16 mRNA and spontaneously secreted IL-16 in vitro. CLL cells express IL-16 mRNA at significantly higher levels in lymphoid tissues than blood, and we observed that IL-16 release was increased in co-cultures of CLL and autologous CD4 + T cells. Elevated plasma IL-16 levels were associated with abnormalities in the immune microenvironment including multiple inflammatory cytokines and chemokines and expansion of type 1 follicular helper T cells. Taken together, our results identify IL-16 as a novel biomarker in CLL with potential functional roles in cellular interactions between CLL cells and T cells.

A Non-Canonical Role for the Glycosyltransferase Enzyme UGT2B17 as a Novel Constituent of the B Cell Receptor Signalosome

In chronic lymphocytic leukemia (CLL), an elevated glycosyltransferase UGT2B17 expression (UGT2B17^HI) identifies a subgroup of patients with shorter survival and poor drug response. We uncovered a mechanism, possibly independent of its enzymatic function, characterized by an enhanced expression and signaling of the proximal effectors of the pro-survival B cell receptor (BCR) pathway and elevated Bruton tyrosine kinase (BTK) phosphorylation in B-CLL cells from UGT2B17^HI patients. A prominent feature of B-CLL cells is the strong correlation of UGT2B17 expression with the adverse marker ZAP70 encoding a tyrosine kinase that promotes B-CLL cell survival. Their combined high expression levels in the treatment of naïve patients further defined a prognostic group with the highest risk of poor survival. In leukemic cells, UGT2B17 knockout and repression of ZAP70 reduced proliferation, suggesting that the function of UGT2B17 might involve ZAP70. Mechanistically, UGT2B17 interacted with several kinases of the BCR pathway, including ZAP70, SYK, and BTK, revealing a potential therapeutic vulnerability. The dual SYK and JAK/STAT6 inhibitor cerdulatinib most effectively compromised the proliferative advantage conferred by UGT2B17 compared to the selective BTK inhibitor ibrutinib. Findings point to an oncogenic role for UGT2B17 as a novel constituent of BCR signalosome also connected with microenvironmental signaling.

Metabolism-based targeting of MYC via MPC-SOD2 axis-mediated oxidation promotes cellular differentiation in group 3 medulloblastoma

Group 3 medulloblastoma (G3 MB) carries the worst prognosis of all MB subgroups. MYC oncoprotein is elevated in G3 MB tumors; however, the mechanisms that support MYC abundance remain unclear. Using metabolic and mechanistic profiling, we pinpoint a role for mitochondrial metabolism in regulating MYC. Complex-I inhibition decreases MYC abundance in G3 MB, attenuates the expression of MYC-downstream targets, induces differentiation, and prolongs male animal survival. Mechanistically, complex-I inhibition increases inactivating acetylation of antioxidant enzyme SOD2 at K68 and K122, triggering the accumulation of mitochondrial reactive oxygen species that promotes MYC oxidation and degradation in a mitochondrial pyruvate carrier (MPC)-dependent manner. MPC inhibition blocks the acetylation of SOD2 and oxidation of MYC, restoring MYC abundance and self-renewal capacity in G3 MB cells following complex-I inhibition. Identification of this MPC-SOD2 signaling axis reveals a role for metabolism in regulating MYC protein abundance that has clinical implications for treating G3 MB.

Impact of Fixed-Duration Oral Targeted Therapies on the Economic Burden of Chronic Lymphocytic Leukemia in Canada

BACKGROUND

Continuous oral targeted therapies (OTT) represent a major economic burden on the Canadian healthcare system, due to their high cost and administration until disease progression/toxicity. The recent introduction of venetoclax-based fixed-duration combination therapies has the potential to reduce such costs. This study aims to estimate the prevalence and the cost of CLL in Canada with the introduction of fixed OTT.

METHODS

A state transition Markov model was developed and included five health states: watchful waiting, first-line treatment, relapsed/refractory treatment, and death. The number of CLL patients and total cost associated with CLL management in Canada for both continuous- and fixed-treatment-duration OTT were projected from 2020 to 2025. Costs included drug acquisition, follow-up/monitoring, adverse event, and palliative care.

RESULTS

The CLL prevalence in Canada is projected to increase from 15,512 to 19,517 between 2020 and 2025. Annual costs were projected at C$880.7 and C$703.1 million in 2025, for continuous and fixed OTT scenarios, respectively. Correspondingly, fixed OTT would provide a total cost reduction of C$213.8 million (5.94%) from 2020 to 2025, compared to continuous OTT.

CONCLUSIONS

Fixed OTT is expected to result in major reductions in cost burden over the 5-year projection, compared to continuous OTT.

The burden of red blood cell transfusions in patients with lower-risk myelodysplastic syndromes and ring sideroblasts: an analysis of the prospective MDS-CAN registry

Many patients with lower-risk myelodysplastic syndromes (LR MDS) require long-term red blood cell (RBC) transfusions to manage anemia. The consequences of RBC transfusions in LR MDS with ring sideroblasts (LR MDS-RS) are not well known. We estimated the association between cumulative RBC dose density and clinical and patient-reported outcomes using data from the MDS-CAN registry for patients enrolled between January 2008 and December 2018. Outcomes included overall survival, hospitalization, and health-related quality of life (HRQoL). A total of 145 enrolled patients with LR MDS and RS ≥5% had a median follow-up time of 27.1 months; 45 had no transfusions during follow-up, 51 had <1 transfusion per month, and 49 had ≥1 transfusion per month. The cumulative density of RBC transfusions was associated with significantly greater mortality, hospitalization, and inferior HRQoL, suggesting that exposure to RBC transfusion may constitute a significant treatment burden in patients with LR MDS-RS.

Canadian evidence-based guideline for frontline treatment of chronic lymphocytic leukemia: 2022 update

Chronic lymphocytic leukemia (cll) is the most common adult leukemia in North America. In 2018, the first unified national guideline in Canada was developed for the front-line treatment of cll that helped guide treatment across the country. As an update in 2022, a group of clinical experts from across Canada came together to provide input and guidance that included new and innovative treatments and approaches that will continue to provide health care professionals with clear guidance on the first-line management of cll. Recommendations were provided in consensus based on available evidence for the first-line treatment of cll.

Consensus opinion from an international group of experts on measurable residual disease in hairy cell leukemia

A significant body of literature has been generated related to the detection of measurable residual disease (MRD) at the time of achieving complete remission (CR) in patients with hairy cell leukemia (HCL). However, due to the indolent nature of the disease as well as reports suggesting long-term survival in patients treated with a single course of a nucleoside analog albeit without evidence of cure, the merits of detection of MRD and attempts to eradicate it have been debated. Studies utilizing novel strategies in the relapse setting have demonstrated the utility of achieving CR with undetectable MRD (uMRD) in prolonging the duration of remission. Several assays including immunohistochemical analysis of bone marrow specimens, multi-parameter flow cytometry and molecular assays to detect the mutant BRAF V600E gene or the consensus primer for the immunoglobulin heavy chain gene (IGH) rearrangement have been utilized with few comparative studies. Here we provide a consensus report on the available data, the potential merits of MRD assessment in the front-line and relapse settings and recommendations on future role of MRD assessment in HCL.

Development of a distributed international patient data registry for hairy cell leukemia

Hairy cell leukemia (HCL) is a rare lymphoproliferative disorder, comprising only 2% of all leukemias. The Hairy Cell Leukemia Foundation (HCLF) has developed a patient data registry to enable investigators to better study the clinical features, treatment outcomes, and complications of patients with HCL. This system utilizes a centralized registry architecture. Patients are enrolled at HCL Centers of Excellence (COE) or via a web-based portal. All data are de-identified, which reduces regulatory burden and increases opportunities for data access and re-use. To date, 579 patients have been enrolled in the registry. Efforts are underway to engage additional COE's to expand access to patients across the globe. This international PDR will enable researchers to study outcomes in HCL in ways not previously possible due to the rarity of the disease and will serve as a platform for future prospective research.

A natural history of lower-risk myelodysplastic syndromes with ring sideroblasts: an analysis of the MDS-CAN registry

Patients with lower-risk (LR) myelodysplastic syndromes (MDS) with ring sideroblasts (RS) have better prognosis than those without RS, but how they fare over time is not fully understood. This study's objective was to assess the natural history of LR MDS with RS ≥5% using MDS-CAN registry individual data. Kaplan-Meier estimates and generalized linear mixed models were used to describe time-to-event outcomes and continuous outcomes, respectively. One hundred and thirty-eight patients were enrolled; median times from diagnosis to enrollment and follow-up were 6.6 and 39.6 months, respectively. Within 5 years of enrollment, 65% of patients had ≥1 red blood cell transfusion dependence episode. Within 5 years of diagnosis, 59% developed iron overload, 38% received iron chelation therapy, 14% progressed to acute myeloid leukemia, and 42% died. Patients exhibited inferior health-related quality of life trends. These first real-world data in LR MDS-RS in Canada indicate a high level of morbidity and mortality over a 5-year period. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT02537990.

Patterns and predictors of referral to the specialized chronic lymphocytic leukemia clinic in Manitoba, Canada

BACKGROUND

Better CLL patient survival has been reported for specialized CLL clinics/hematologists (compared to other CLL patients). It is possible that improved survival is driven by a better prognosis of referred patients.

METHODS

We used logistic regression to calculate the odds ratios (ORs) and 95 % confidence intervals 95 %CIs) of the association between patient characteristics and CLL referral of all persons diagnosed in 2005-2016 with a pathologically-confirmed CLL or SLL.

RESULTS

Two-thirds of 1293 patients were referred to the CLL clinic. Referred patients were younger (16 % vs 44 % were 80 +) and in better health (47 % vs 56 % with a chronic diseases) than non-referred patients. Referral increased over time: in 2005-2010, about 60 % of patients were referred; in 2011-2016, this increased to 76 %. Gender did not affect referral (the OR for females is 1.0, 95 %CI 0.8-1.2), but age played a major role; CLL patients diagnosed at age 80 + were less likely to be referred than patients diagnosed < 60, 0.2 (0.1-0.3).

CONCLUSION

Because referral to Manitoba's specialized CLL clinic is associated with age and the patient's overall health before referral, one should be careful in interpreting differences in outcomes between CLL patients based on referral status alone.

High transferrin saturation predicts inferior clinical outcomes in patients with myelodysplastic syndromes

Iron overload (IO) reflected by elevated ferritin is associated with increased mortality in myelodysplastic syndromes (MDS), however, ferritin is an imperfect metric. Elevated labile plasma iron correlates with clinical outcomes and transferrin saturation (TSAT) >80%, but is not readily measurable. The trajectory of TSAT, and its association with clinical outcomes remain undefined. Canadian MDS registry patients were evaluated. Mean TSAT, mean ferritin and transfusion dose density (TDD) were determined. Survival was evaluated by TSAT and ferritin (<50%, 50-80%, >80%), (≤500 μg/L, 501-800 μg/L, >800 μg/L). In 718 patients, median age was 74 years; 12%, 31%, 29%, 15% and 13% were IPSS-R very low, low, intermediate, high and very high. TSAT and ferritin were moderately correlated (r=0.63, P<0.0001). TSAT increased over time in transfusion- dependent patients (P=0.006). Higher TSAT and ferritin were associated with inferior 5-year overall (OS), progression- free (PFS), and leukemia-free survival (LFS) (P≤0.008) and higher TDD with inferior 5-year OS. TSAT >80% trended with inferior cardiac death-free survival (P=0.053). In univariate analysis, age, IPSS-R, blast percentage by Eastern Cooperative Oncology Group Performance Status, frailty, Charlson Comorbidity Index, iron chelation (Y/N), TDD, TSAT and ferritin were significantly associated with inferior OS. By multivariable analysis, TSAT >80% (P=0.007) remained significant for OS (R2 30.3%). In MDS, TSAT >80% and ferritin >800 μg/L portended inferior OS, PFS and LFS. TSAT may indicate the presence of oxidative stress, and is readily measurable in a clinical setting. The relationship between TSAT and cardiac death-free survival warrants further study.

Patient-driven research: Initial results from a prospective health-related quality of life study performed at the request of patients living with hairy cell leukemia

A diagnosis of leukemia can have a profound effect on patients' health-related quality of life (HRQoL), however this has not been measured prospectively in patients with hairy cell leukemia (HCL). At the request of patients living with HCL who had identified this gap in knowledge about the disease, we conducted a longitudinal study of HRQoL among patients enrolled in the HCL Patient Data Registry (PDR). From September 1, 2018 to September 1, 2020, 165 patients were enrolled in the study and completed the baseline survey. The Functional Assessment of Cancer Therapy - Leukemia (FACT-Leu) was used to measure patients' HRQoL. Results show that newly diagnosed HCL patients reported the lowest HRQoL, followed by patients in relapse and those on "watch and wait." Factors associated with higher (better) FACT-Leu total scores in the multivariable analysis included older age, higher social support, and greater physical activity. These same factors were associated with lower levels of fatigue. In rare diseases where it is difficult to perform large prospective studies, patient/researcher collaborations are critical for the identification of studies that are of importance to patients and their families in order to maximize the benefits of the research and improve the lives of patients living with HCL.

Acalabrutinib ± obinutuzumab versus obinutuzumab + chlorambucil in treatment-naïve chronic lymphocytic leukemia: Five-year follow-up of ELEVATE-TN

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Background: For ELEVATE-TN (NCT02475681), we previously reported superior efficacy of acalabrutinib (A) ± obinutuzumab (O) vs O + chlorambucil (Clb) in patients (pts) with treatment-naive (TN) chronic lymphocytic leukemia (CLL) at 28.3 and 46.9 months (mo) median follow-up. Now, we report results from a 5-y update. Methods: Pts were randomized to A+O, A, or O+Clb. Pts who progressed on O+Clb could cross over to A monotherapy. Investigator-assessed (INV) progression-free survival (PFS), INV overall response rate (ORR), overall survival (OS), and safety were evaluated. Results: A total of 535 pts (A+O, n=179; A, n=179; O+Clb, n=177) had a median age of 70 y. At a median follow-up of 58.2 mo (range, 0.0–72.0; data cutoff Oct 1, 2021), median PFS was not reached (NR) (hazard ratio [HR]: 0.11) for A+O and A (HR: 0.21) vs 27.8 mo for O+Clb (both P<0.0001). Estimated 60-mo PFS rates were 84% (A+O), 72% (A), and 21% (O+Clb). Median OS was NR in any treatment arm, and significantly longer in the A+O vs O+Clb arms (HR: 0.55; P=0.0474); estimated 60-mo OS rates were 90% (A+O), 84% (A), and 82% (O+Clb). ORR was significantly higher with A+O (96%; 95% CI 92–98) and A (90%; 85–94) vs O+Clb (83%; 77–88; P<0.0001 [A+O], P=0.0499 [A]). Complete response (CR)/CR with incomplete hematologic recovery (CRi) rates were higher with A+O (29%/3%) vs O+Clb (13%/1%); 13%/1% had CR/CRi with A; CR increased since the interim analysis (previously 21% [A+O] and 7% [A]). Adverse events (AEs) and treatment exposure are shown in the Table. Treatment is ongoing in 65% (A+O) and 60% (A) of pts; the most common reasons for treatment discontinuation were AEs (17% [A+O], 16% [A], 14% [O+Clb]) and progressive disease (6%, 10%, 2%, respectively). Crossover from O+Clb to A occurred in 72 (41%) patients; 25% of these pts discontinued A (10% due to AEs and 11% due to progressive disease). Conclusions: After a 5-y follow-up, efficacy and safety of A+O and A monotherapy were maintained, with significantly longer OS in the A+O arm compared with O+Clb. Clinical trial information: NCT02475681. [Table: see text]

Impact of sex on outcomes in patients with hairy cell leukemia (HCL): An HCL Patient Data Registry (PDR) analysis

7577

Background: HCL is a rare indolent leukemia that is more common in men, with a 4:1 male predominance. To date, no studies have characterized the potential difference in outcomes of HCL between male and female patients. Hence, we sought to evaluate the outcomes of female HCL patients using the HCL-PDR. Methods: The HCL Foundation sponsored the development of HCL-PDR to characterize the clinical features and outcomes of this rare leukemia. HCL-PDR is an international multicenter PDR that includes patient, disease and treatment information abstracted from medical records. Adult patients enrolled in the HCL-PDR were included in the study. Female patients with HCL were the study population, with males as the comparator. The primary endpoint was the time to next treatment (TTNT) in females compared to males. Secondary endpoints included response rates (RR) and predictors of TTNT. Responses were categorized as: complete response (CR) including CR/CRu (CR unconfirmed)/HR (hematologic response), and partial response (PR), which included PR/PRu (PR unconfirmed)/pHR (partial HR). CRu was defined as no disease in bone marrow (BM) without available blood counts and HR as blood counts meeting criteria for HR, but no available BM. Cox proportional hazard models were used to estimate the hazard ratios for TTNT risk. Results: 357 patients were included: 265 males and 92 females. Table shows baseline characteristics stratified by sex. Among the patients who had disease status assessed after first treatment (n=224, males 169 and females 55), there was no significant difference in RR. However, females had significantly longer median TTNT (17.6 years) relative to males (8 years, HR 0.54, 95% CI 0.32-0.91, p=0.02) that remained significant after adjusting for other variables (RR and BRAF mutation) in multivariable analysis (HR 0.32, 95% CI 0.11-0.97, p=0.04). Factors predictive of longer TTNT include female sex and CR (HR.0.26, 95% CI 0.11-0.57, p=0.001). Conclusions: This is the first study to date reporting the clinical characteristics and outcomes in female HCL patients. The significantly longer TTNT in females compared to males may be related to factors such as underlying molecular features or hormonal influences. This finding needs to be explored further. [Table: see text]

Real world risk of infusion reactions and effectiveness of front-line obinutuzumab plus chlorambucil compared with other frontline treatments for chronic lymphocytic leukemia

Background

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in North America. Previous studies have shown improved progression free survival (PFS) and response rates in unfit patients treated with obinutuzumab compared to other regimens. The aim of this study was to evaluate the obinutuzumab-chlorambucil regimen in the context of historical treatments and first-dose infusion reactions at CancerCare Manitoba (CCMB).

Methods

A retrospective chart review was conducted for patients treated with obinutuzumab from January 1, 2014 to December 31, 2017 at CCMB. A minimum data set was extracted for patients treated with other front-line therapies. Descriptive statistics were used to evaluate patient demographics, toxicity, duration and dosing of obinutuzumab treatment. Kaplan–Meier curves were used to evaluate time-to-next-treatment (TTNT), overall survival (OS) and PFS for patients treated with obinutuzumab. A multivariable logistic regression model was used to investigate associations between infusion related reactions (IRRs) and age at treatment, pre-treatment lymphocyte count, cumulative illness rating scale (CIRS) and receipt of prior chemotherapy.

Results

Forty seven percent of patients receiving frontline therapy received chlorambucil and obinutuzumab. Sixty-seven patients were treated with obinutuzumab and consisted of 36 males (53.7%) and 31 females (46.3%) with 29 patients (43.3%) over age 75 years. Rates of grade 3 and 4 obinutuzumab IRRs were lower (6%) compared to the CLL11 clinical trial (20%) due to local practices including slower infusion rates and using chlorambucil before starting obinutuzumab treatment. Many patients had difficulty tolerating the full dosage of chlorambucil. Only 26 patients (38.8%) had their dose of chlorambucil escalated to the full dose of 0.5 mg/kg. In addition, only 18 patients (26.9%) received all doses of obinutuzumab and all 12 doses of chlorambucil.

Conclusions

In summary, first dose infusion reactions with obinutuzumab can be markedly reduced by using chlorambucil to decrease the lymphocyte count before obinutuzumab and by using a very slow initial obinutuzumab infusion rate. Modifications in chlorambucil dosing and obinutuzumab administration can improve tolerance without significant loss in efficacy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09256-2.

Frontline Treatment of the Young, Fit Patient with CLL: A Canadian Perspective

From a Canadian perspective, there has been a limited discussion on the frontline management of young, fit patients with chronic lymphocytic leukemia (CLL). The prevalence of this population ranges between 2 and 22 per 100,000 persons in Canada and varies by region. Until recently, fixed-duration fludarabine-based chemoimmunotherapy (CIT) was the primary treatment option in Canada for this patient population. The ECOG1912 trial has since demonstrated that ibrutinib and rituximab therapy are as effective as fludarabine-cyclophosphamide-rituximab (FCR) in this population. The ALLIANCE trial showed that rituximab added no incremental benefit to ibrutinib. Canadian payors and physicians adopted ibrutinib monotherapy as the CLL standard of care, even in the young, fit population, although frontline ibrutinib therapy is often reimbursed by provincial public drug plans only in patients with high-risk disease or those who are unfit to receive fludarabine. Young, fit patients with CLL and their physicians may now choose between continuous ibrutinib monotherapy and fixed-duration CIT with FCR. Factors affecting this choice include patient preference and the short- and long-term toxicity profiles of both regimens, and a risk-based algorithm is provided. As new continuous-therapy options enter the market, all treatment choices present benefits and risks that must be communicated to the patient.

Patient-reported fatigue refines prognosis in higher-risk myelodysplastic syndromes (MDS): a MDS-CAN study

The incorporation of patient-reported outcomes with traditional disease risk classification was found to strengthen survival prediction in patients with myelodysplastic syndromes (MDS). In the present Canadian MDS registry analysis, we validate a recently reported prognostic model, the Fatigue-International Prognostic Scoring System among higher-risk patients [FA-IPSS(h)], which incorporates patients' reported fatigue, assessed by the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life-Core 30 (QLQ-C30), with a threshold of ≥45 points, in higher IPSS score, stratifying them into distinct subgroups with different survival outcomes. We further validated this concept, using the Revised IPSS >3·5 as cut-off for the definition of higher-risk MDS, and patients' reported fatigue according to Edmonton Symptom Self-Assessment Scale (ESAS) Global Fatigue Scale (GFS), a single-item fatigue rating scale, which is easier to deploy. This emphasises the power of self-reported fatigue at refining overall survival predictions in higher-risk MDS and further bolsters the importance of considering patient-related outcomes in global assessments.

Acalabrutinib ± obinutuzumab versus obinutuzumab + chlorambucil in treatment-naïve chronic lymphocytic leukemia: Elevate-TN four-year follow up

7509

Background: Early results from ELEVATE-TN (NCT02475681) at a median follow-up of 28.3 mo demonstrated superior efficacy of acalabrutinib (A) ± obinutuzumab (O) compared with O + chlorambucil (Clb) in patients (pts) with treatment-naïve (TN) chronic lymphocytic leukemia (CLL) (Sharman et al. Lancet 2020;395:1278-91). Results from a 4-year update are reported here. Methods: Pts received A±O or O+Clb. Crossover to A monotherapy was permitted in pts who progressed on O+Clb. Investigator-assessed (INV) progression-free survival (PFS), INV overall response rate (ORR), overall survival (OS), and safety were evaluated. Results: 535 pts (A+O, n=179; A, n=179; O+Clb, n=177) were randomized with a median age of 70 y; 63% had unmutated IGHV and 9% del(17p). At a median follow-up of 46.9 mo (range, 0.0–59.4; data cutoff: Sept 11, 2020), the median PFS was not reached (NR) for A+O and A pts vs 27.8 mo for O+Clb pts (both P<0.0001). In pts with unmutated IGHV, the median PFS was NR (A+O and A) vs 22.2 mo among O+Clb pts (both P<0.0001). In pts with del(17p), the median PFS was NR (A+O and A) vs 17.7 mo for O+Clb ( P<0.005). Estimated 48-mo PFS rates were 87% for A+O, 78% for A, and 25% for O+Clb. Median OS was NR in any treatment arm with a trend towards significance in the A+O group (A+O vs O+Clb, P=0.0604); estimated 48-mo OS rates were 93% (A+O), 88% (A), and 88% (O+Clb). ORR was significantly higher with A+O (96.1%; 95% CI 92.1–98.1) vs O+Clb (82.5%; 95% CI 76.2–87.4; P<0.0001); ORR with A was 89.9% (95% CI 84.7–93.5; P=0.035 vs O+Clb). Complete response/complete response with incomplete hematologic recovery (CR/CRi) rates were higher with A+O (26.8%/3.9%) vs O+Clb (12.4%/0.6%); 10.6%/0.6% had CR/CRi with A. Common adverse events (AEs) and AEs of interest are shown in the Table. Overall treatment discontinuation rates were 25.1% (A+O), 30.7% (A), and 22.6% (O+Clb); the most common reasons were AEs (12.8%, 12.3%, 14.7%, respectively) and progressive disease (4.5%, 7.8%, 1.7%). Most pts (77.4%) completed O+Clb treatment. Conclusions: With a median follow-up of 46.9 mo (̃4y), the efficacy and safety of A+O and A monotherapy was maintained, with an increase in CR since the interim analysis (from 21% to 27% [A+O] and from 7% to 11% [A]) and low rates of discontinuation.[Table: see text]

Altered T Follicular Helper Cell Subsets and Function in Chronic Lymphocytic Leukemia

Follicular helper T cells (T_FH) have specialized properties in promoting normal B cell activation but their role in chronic lymphocytic leukemia (CLL) is unknown. We find that T_FH cells are elevated in CLL patients and are phenotypically abnormal, expressing higher levels of PD-1, TIGIT, CD40L, IFNγ and IL-21, and exhibiting abnormal composition of T_FH1, T_FH2 and T_FH17 subsets. Frequencies of CD4-positive T cells expressing T_FH1 markers and IL-21 were positively correlated with patient lymphocyte counts and RAI stage, suggesting that accumulation of abnormal T_FH cells is concomitant with expansion of the leukemic B cell clone. Treatment with ibrutinib led to normalization of T_FH frequencies and phenotype. T_FH cells identified in CLL bone marrow display elevated expression of several functional markers compared to blood T_FH cells. CLL T cell-B cell co-culture experiments revealed a correlation of patient T_FH frequencies with functional ability of their CD4-positive T cells to promote CLL proliferation. Conversely, CLL cells can preferentially activate the T_FH cell subset in co-culture. Together our results indicate that CLL development is associated with expansion of abnormal T_FH populations that produce elevated levels of cytokines and costimulatory molecules which may help support CLL proliferation.

Natural history of monoclonal B-cell lymphocytosis among relatives in CLL families

Chronic lymphocytic lymphoma (CLL) has one of the highest familial risks among cancers. Monoclonal B-cell lymphocytosis (MBL), the precursor to CLL, has a higher prevalence (13%-18%) in families with 2 or more members with CLL compared with the general population (5%-12%). Although, the rate of progression to CLL for high-count MBLs (clonal B-cell count ≥500/µL) is ∼1% to 5%/y, no low-count MBLs have been reported to progress to date. We report the incidence and natural history of MBL in relatives from CLL families. In 310 CLL families, we screened 1045 relatives for MBL using highly sensitive flow cytometry and prospectively followed 449 of them. MBL incidence was directly age- and sex-adjusted to the 2010 US population. CLL cumulative incidence was estimated using Kaplan-Meier survival curves. At baseline, the prevalence of MBL was 22% (235/1045 relatives). After a median follow-up of 8.1 years among 449 relatives, 12 individuals progressed to CLL with a 5-year cumulative incidence of 1.8%. When considering just the 139 relatives with low-count MBL, the 5-year cumulative incidence increased to 5.7%. Finally, 264 had no MBL at baseline, of whom 60 individuals subsequently developed MBL (2 high-count and 58 low-count MBLs) with an age- and sex-adjusted incidence of 3.5% after a median of 6 years of follow-up. In a screening cohort of relatives from CLL families, we reported progression from normal-count to low-count MBL to high-count MBL to CLL, demonstrating that low-count MBL precedes progression to CLL. We estimated a 1.1% annual rate of progression from low-count MBL, which is in excess of that in the general population.

Ex Vivo Mitochondrial Respiration Parallels Biochemical Response to Ibrutinib in CLL Cells

Mitochondrial respiration is becoming more commonly used as a preclinical tool and potential biomarker for chronic lymphocytic leukemia (CLL) and activated B-cell receptor (BCR) signaling. However, respiration parameters have not been evaluated with respect to dose of ibrutinib given in clinical practice or the effect of progression on ibrutinib treatment on respiration of CLL cells. We evaluated the impact of low and standard dose ibrutinib on CLL cells from patients treated in vivo on mitochondrial respiration using Oroboros oxygraph. Cytokines CCL3 and CCL4 were evaluated using the Mesoscale. Western blot analysis was used to evaluate the BCR and apoptotic pathways. We observed no difference in the mitochondrial respiration rates or levels of plasma chemokine (C-C motif) ligands 3 and 4 (CCL3/CCL4), β-2 microglobulin (β-2 M) and lactate dehydrogenase (LDH) between low and standard doses of ibrutinib. This may confirm why clinical observations of the safety and efficacy of low dose ibrutinib are observed in practice. Of interest, we also observed that the mitochondrial respiration of CLL cells paralleled the increase in β-2 M and LDH at progression. Our study further supports mitochondrial respiration as a biomarker for response and progression on ibrutinib in CLL cells and a valuable pre-clinical tool.

Bruton tyrosine kinase inhibitors for the frontline treatment of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (cll) is the most commonly diagnosed adult leukemia in Canada. Biologic heterogeneity of cll between patients results in variable disease trajectories and responses to therapy. Notably, compared with patients lacking high-risk features, those with such features-such as deletions in chromosome 17p, aberrations in the TP53 gene, or unmutated immunoglobulin heavy chain variable region genes-experience inferior outcomes and responses to standard chemoimmunotherapy. Novel agents that target the B cell receptor signalling pathway, such as Bruton tyrosine kinase (btk) inhibitors, have demonstrated clinical efficacy and safety in patients with treatment-naïve cll, particularly those with high-risk features. However, given the current lack of head-to-head trials comparing btk inhibitors, selection of the optimal btk inhibitor for patients with cll is unclear and requires consideration of multiple factors. In the present review, we focus on the efficacy, safety, and pharmacologic features of the btk inhibitors that are approved or under clinical development, and we discuss the practical considerations for the use of those agents in the Canadian treatment landscape.

PD-1 inhibition in malignant melanoma and lack of clinical response in chronic lymphocytic leukemia in the same patients: a case series

Chronic lymphocytic leukemia (cll) is the most common adult leukemia in the Western world. Unfortunately, affected patients are often immunosuppressed and at increased risk of infection and secondary malignancy. Previous meta-analysis has found that patients with cll have a risk of melanoma that is increased by a factor of 4 compared with the general population. Recent advances in the understanding of the PD receptor pathway have led to immunotherapies that target cancer cells. The use of PD-1 inhibitors is now considered first-line treatment for BRAF wild-type metastatic melanoma. Interestingly, early preclinical data suggest that inhibition of that pathway could also be used in the treatment of cll; however, recent clinical data did not support the effectiveness of that approach. In this case series, we highlight 2 cases in which patients with cll and concurrent malignant melanoma underwent treatment with PD-1 inhibitors and were found to experience reductions in their white blood cell counts without improvement in their hemoglobin. Those cases further illustrate that treatment of cll with PD-1 inhibitors is ineffective.

Acalabrutinib with or without obinutuzumab versus chlorambucil and obinutuzmab for treatment-naive chronic lymphocytic leukaemia (ELEVATE TN): a randomised, controlled, phase 3 trial

BACKGROUND

Acalabrutinib is a selective, covalent Bruton tyrosine-kinase inhibitor with activity in chronic lymphocytic leukaemia. We compare the efficacy of acalabrutinib with or without obinutuzumab against chlorambucil with obinutuzumab in patients with treatment-naive chronic lymphocytic leukaemia.

METHODS

ELEVATE TN is a global, phase 3, multicentre, open-label study in patients with treatment-naive chronic lymphocytic leukaemia done at 142 academic and community hospitals in 18 countries. Eligible patients had untreated chronic lymphocytic leukaemia and were aged 65 years or older, or older than 18 years and younger than 65 years with creatinine clearance of 30-69 mL/min (calculated by use of the Cockcroft-Gault equation) or Cumulative Illness Rating Scale for Geriatrics score greater than 6. Additional criteria included an Eastern Cooperative Oncology Group performance status score of 2 or less and adequate haematologic, hepatic, and renal function. Patients with significant cardiovascular disease were excluded, and concomitant treatment with warfarin or equivalent vitamin K antagonists was prohibited. Patients were randomly assigned (1:1:1) centrally via an interactive voice or web response system to receive acalabrutinib and obinutuzumab, acalabrutinib monotherapy, or obinutuzumab and oral chlorambucil. Treatments were administered in 28-day cycles. To reduce infusion-related reactions, acalabrutinib was administered for one cycle before obinutuzumab administration. Oral acalabrutinib was administered (100 mg) twice a day until progressive disease or unacceptable toxic effects occurred. In the acalabrutinib-obinutuzumab group, intravenous obinutuzumab was given on days 1 (100 mg), 2 (900 mg), 8 (1000 mg), and 15 (1000 mg) of cycle 2 and on day 1 (1000 mg) of cycles 3-7. In the obinutuzumab-chlorambucil group, intravenous obinutuzumab was given on days 1 (100 mg), 2 (900 mg), 8 (1000 mg), and 15 (1000 mg) of cycle 1 and on day 1 (1000 mg) of cycles 2-6. Oral chlorambucil was given (0·5 mg/kg) on days 1 and 15 of each cycle, for six cycles. The primary endpoint was progression-free survival between the two combination-therapy groups, assessed by independent review committee. Crossover to acalabrutinib was allowed in patients who progressed on obinutuzumab-chlorambucil. Safety was assessed in all patients who received at least one dose of treatment. Enrolment for this trial is complete, and the study is registered at ClinicalTrials.gov, NCT02475681.

FINDINGS

Between Sept 14, 2015, and Feb 8, 2017, we recruited 675 patients for assessment. 140 patients did not meet eligibility criteria, and 535 patients were randomly assigned to treatment. 179 patients were assigned to receive acalabrutinib-obinutuzumab, 179 patients were assigned to receive acalabrutinib monotherapy, and 177 patients were assigned to receive obinutuzumab-chlorambucil. At median follow-up of 28·3 months (IQR 25·6-33·1), median progression-free survival was longer with acalabrutinib-obinutuzumab and acalabrutinib monotherapy, compared with obinutuzumab-chlorambucil (median not reached with acalabrutinib and obinutuzumab vs 22·6 months with obinutuzumab, hazard ratio [HR] 0·1; 95% CI 0·06-0·17, p<0·0001; and not reached with acalabrutinib monotherapy vs 22·6 months with obinutuzumab, 0·20; 0·13-0·3, p<0·0001). Estimated progression-free survival at 24 months was 93% with acalabrutinib-obinutuzumab (95% CI 87-96%), 87% with acalabrutinib monotherapy (81-92%), and 47% with obinutuzumab-chlorambucil (39-55%). The most common grade 3 or higher adverse event across groups was neutropenia (53 [30%] of 178 patients in the acalabrutinib-obinutuzumab group, 17 [9%] of 179 patients in the acalabrutinib group, and 70 [41%] of 169 patients in the obinutuzumab-chlorambucil group). All-grade infusion reactions were less frequent with acalabrutinib-obinutuzumab (24 [13%] of 178 patients) than obinutuzumab-chlorambucil (67 [40%] of 169 patients). Grade 3 or higher infections occurred in 37 (21%) patients given acalabrutinib-obinutuzumab, 25 (14%) patients given acalabrutinib monotherapy, and 14 (8%) patients given obinutuzumab-chlorambucil. Deaths occurred in eight (4%) patients given acalabrutinib-obinutuzumab, 12 (7%) patients given acalabrutinib, and 15 (9%) patients given obinutuzumab-chlorambucil.

INTERPRETATION

Acalabrutinib with or without obinutuzumab significantly improved progression-free survival over obinutuzumab-chlorambucil chemoimmunotherapy, providing a chemotherapy-free treatment option with an acceptable side-effect profile that was consistent with previous studies. These data support the use of acalabrutinib in combination with obinutuzumab or alone as a new treatment option for patients with treatment-naive symptomatic chronic lymphocytic leukaemia.

FUNDING

Acerta Pharma, a member of the AstraZeneca Group, and R35 CA198183 (to JCB).

Updates from the American Society of Hematology 2019 annual meeting: practice-changing studies in treatment-naïve chronic lymphocytic leukemia

The 2019 annual meeting of the American Society of Hematology took place 7-10 December in Orlando, Florida. At the meeting, results from key studies in treatment-naïve chronic lymphocytic leukemia (cll) were presented. Of those studies, phase iii oral presentations focused on the efficacy and safety of therapy with inhibitors of Bruton tyrosine kinase (btk) and Bcl-2. One presentation reported updated results of the Eastern Cooperative Oncology Group 1912 trial comparing the efficacy and safety of ibrutinib-rituximab with that of fludarabine-cyclophosphamide-rituximab in patients less than 70 years of age with cll. A second presentation reported interim results of the elevate tn trial, which is investigating the efficacy and safety of acalabrutinib-obinutuzumab or acalabrutinib monotherapy compared with chlorambucil-obinutuzumab. A third presentation reported on the single-agent zanubrutinib arm of the sequoia trial in patients with del(17p). The final presentation constituted a data update from the cll14 trial, which is evaluating fixed-duration venetoclax-obinutuzumab compared with chlorambucil-obinutuzumab, including the association of minimal residual disease status with progression-free survival. Our meeting report describes the foregoing studies and presents interviews with investigators and commentaries by Canadian hematologists about potential effects on Canadian practice.

Mitochondrial Respiration Correlates with Prognostic Markers in Chronic Lymphocytic Leukemia and Is Normalized by Ibrutinib Treatment

Mitochondrial bioenergetics profiling, a measure of oxygen consumption rates, correlates with prognostic markers and can be used to assess response to therapy in chronic lymphocytic leukemia (CLL) cells. In this study, we measured mitochondrial respiration rates in primary CLL cells using respirometry to evaluate mitochondrial function. We found significant increases in mitochondrial respiration rates in CLL versus control B lymphocytes. We also observed amongst CLL patients that advanced age, female sex, zeta-chain-associated protein of 70 kD (ZAP-70⁺), cluster of differentiation 38 (CD38⁺), and elevated β2-microglobulin (β2-M) predicted increased maximal respiration rates. ZAP-70⁺ CLL cells exhibited significantly higher bioenergetics than B lymphocytes or ZAP-70⁻ CLL cells and were more sensitive to the uncoupler, carbonyl cyanide-p-trifluoro-methoxyphenylhydrazone (FCCP). Univariable and multivariable linear regression analysis demonstrated that ZAP-70⁺ predicted increased maximal respiration. ZAP-70⁺ is a surrogate for B cell receptor (BCR) activation and can be targeted by ibrutinib, which is a clinically approved Bruton’s tyrosine kinase (BTK) inhibitor. Therefore, we evaluated the oxygen consumption rates (OCR) of CLL cells and plasma chemokine (C-C motif) ligands 3 and 4 (CCL3/CCL4) levels from ibrutinib-treated patients and demonstrated decreased OCR similar to control B lymphocytes, suggesting that ibrutinib treatment resets the mitochondrial bioenergetics, while diminished CCL3/CCL4 levels indicate the down regulation of the BCR signaling pathway in CLL. Our data support evaluation of mitochondrial respiration as a preclinical tool for the response assessment of CLL cells.

IND.216: a phase II study of buparlisib and associated biomarkers, raptor and p70S6K, in patients with relapsed and refractory chronic lymphocytic leukemia

Buparlisib is an orally available pan-Class I PI3K inhibitor, that is more potent than idelalisib in vitro. Its distinct toxicities include hyperglycemia, hypertension, and mood disturbance. IND216 is a single arm phase II trial of buparlisib in Relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL). Fourteen patients were enrolled, 13 were evaluable for response and toxicity. Six of 13 patients had a partial response (46%) with a median duration of response of 15.5 months, all 11 patients with tumor assessment experienced tumor shrinkage. The most common adverse events (≥15%) were hyperglycemia, fatigue, anxiety, and gastrointestinal toxicities; all were < grade 3 except for fatigue. Three patients stopped therapy for alterations in mood. Lower levels of raptor were significantly associated with greater tumor shrinkage, suggesting that raptor could be a biomarker for response. This requires further validation in a larger CLL patient cohort. The clinical activity of buparlisib is comparable to other phosphatidylinositol-3-kinase inhibitors, with a different toxicity profile.Novelty and impactBuparlisib, an oral, pan PI3 kinase inhibitor, is associated with a 46% partial response rate among patients with relapse chronic lymphocytic leukemia (CLL). This is a similar clinical activity to other phosphatidylinositol-3-kinase inhibitors tested. However, buparlisib has a distinct toxicity profile, characterized by hyperglycemia, hypertension, and mood alteration. In agreement with our previous preclinical study, our results suggest that basal raptor expression in CLL correlates with clinical response to buparlisib.

An MDS-specific frailty index based on cumulative deficits adds independent prognostic information to clinical prognostic scoring

The frailty index (FI) is based on the principle that the more deficits an individual has, the greater their risk of adverse outcomes. It is expressed as a ratio of the number of deficits present to the total number of deficits considered. We developed an MDS-specific FI using a prospective MDS registry and assessed its ability to add prognostic power to conventional prognostic scores in MDS. The 42 deficits included in this FI included measurements of physical performance, comorbidities, laboratory values, instrumental activities of daily living, quality of life and performance status. Of 644 patients, 440 were eligible for FI calculation. The median FI score was 0.25 (range 0.05-0.67), correlated with age and IPSS/IPSS-R risk scores and discriminated overall survival. With a follow-up of 20 months, survival was 27 months (95% CI 24-30.4). By multivariate analysis, age >70, FI, transfusion dependence, and IPSS were significant covariates associated with OS. The incremental discrimination improvement of the frailty index was 37%. We derived a prognostic score with five risk groups and distinct survivals ranging from 7.4 months to not yet reached. If externally validated, the MDS-FI could be used as a tool to refine the risk stratification of current clinical prognostication models.

Complete resolution of chylopericardium after chemotherapy for chronic lymphocytic leukemia

Nontraumatic chylous pleural effusions (chylothorax) and pericardial effusions (chylopericardium) are rare. They can, however, accompany intrathoracic malignancies and, most commonly, lymphomas. An association of chronic lymphocytic leukemia (cll) with chylopericardium has rarely been reported. A 68-year-old woman with cll, previously treated with single-agent fludarabine in the community, developed pleuritic chest pain and a new pericardial effusion. Computed tomography (ct) imaging of her chest revealed a large pericardial effusion with progressive lymphadenopathy. Pericardiocentesis identified a chylous effusion, and complete evacuation was achieved by catheter drainage. The cll was not treated. An asymptomatic pericardial effusion subsequently recurred. Pericardiocentesis was not repeated. Lymph node biopsy and flow cytometry revealed no evidence of large-cell lymphoma transformation. The patient was treated with 6 cycles of chlorambucil and obinutuzumab. Imaging of her chest by ct between cycles 2 and 3 revealed a marked resolution of the intrathoracic lymphadenopathy, with complete disappearance of the pericardial effusion. Repeat imaging at 5 months and again at 3 years after completion of chemotherapy demonstrated no recurrence of either the lymphadenopathy or the pericardial effusion. The mechanism of production and the treatment of chylous effusions are poorly defined. In this case, resolution of the pericardial effusion with effective chemotherapy is postulated to have alleviated obstruction of anterograde lymphatic flow facilitating drainage into the systemic venous system and allowing for spontaneous complete resolution of the pericardial effusion without surgical intervention.

Descriptive analysis of dosing and outcomes for patients with ibrutinib-treated relapsed or refractory chronic lymphocytic leukemia in a Canadian centre

Background

Ibrutinib is an approved treatment for relapsed or refractory chronic lymphocytic leukemia (cll) and small lymphocytic lymphoma (sll). The effect of ibrutinib dose reduction compared with discontinuation in a population-based setting is unclear.

Methods

To examine the patterns of ibrutinib use in a Canadian population-based setting, we analyzed a retrospective cohort of patients with relapsed or refractory cll or sll treated with ibrutinib.

Results

The 64 patients diagnosed with cll or sll had a median age of 76.5 years. Most had unmutated ighv (immunoglobulin variable heavy chain). A hematologic response occurred in 39 patients regardless of the ibrutinib dose. The most common toxicities were infection, bruising or bleeding, and musculoskeletal problems, with a median time to first toxicity of 14 days. More than half the cohort experienced a dose reduction, with musculoskeletal problems, cytopenias, and infection being the leading causes; surgery was the most frequent indication for holding treatment. Only 26 of the 64 patients (40.6%) stayed on the recommended maximal dose of ibrutinib. No differences in reported toxicities or hematologic response rates were evident between the patients receiving maximal and submaximal therapy. At the end of the study period, 53 patients from the initial cohort remained on ibrutinib.

Conclusions

More than half the study patients received ibrutinib therapy at a submaximal dose without evidence of increased frequency of toxicities or disease progression. The rate of ibrutinib discontinuation was lower in our cohort than has been reported in other settings. Submaximal ibrutinib dosing will have to be further systematically evaluated.

Statin Use and Chronic Lymphocytic Leukemia Incidence: A Nested Case-Control Study in Manitoba, Canada

BACKGROUND

Recent studies have reported reduced risk of chronic lymphocytic leukemia (CLL) among statin users. However, the possibility that the effect of statins may differ by their chemical or pharmacodynamic properties has not been investigated.

METHODS

In this nested case-control study, all Manitobans ages ≥40 years when diagnosed with CLL (as a first cancer) from 1999 to 2014 (n = 1,385) were matched (on gender, age, residence, and duration of insurance coverage) to cancer-free controls (n = 6,841). Using conditional logistic regression, statin use was analyzed by individual statins and groups: hydrophilic, low-potency lipophilic (fluvastatin and lovastatin), and high-potency lipophilic statins.

RESULTS

Statin users constituted 27% and 28% of the CLL cases and controls, respectively. After adjusting for potential confounding by indication, patterns of healthcare utilization, and use of other drugs, CLL incidence was not associated with use of hydrophilic [odds ratio (OR) = 1.08; 95% confidence interval (CI), 0.86-1.34] or high-potency lipophilic (OR = 0.94; 95% CI, 0.79-1.11) statins. Low-potency lipophilic statins were associated with a lower risk of CLL (OR = 0.64; 95% CI, 0.45-0.92), with stronger association (OR = 0.44; 95% CI, 0.22-0.88) observed with more regular use (half to full standard dose on average).

CONCLUSIONS

We found an association between low-potency lipophilic statin use and reduced CLL risk, with a possible dose-response effect.

IMPACT

Although requiring replication in future studies, our findings suggest that the effect of statins on CLL risk may depend on their specific chemical or pharmacodynamic properties.

Expression and function of phosphoinositide 3-kinase delta in mesenchymal stromal cells from normal and leukaemic bone marrow

Within lymphoid tissues, chronic lymphocytic leukaemia (CLL) cells interact with mesenchymal stromal cells (MSC). Inhibitors of phosphoinositide 3-kinase delta (PI3Kδ) cause release of CLL cells from lymphoid tissues into blood. PI3Kδ inhibitors are thought to target only CLL and other immune cells because PI3Kδ expression is restricted to haematopoietic cells. We found that PI3Kδ is unexpectedly expressed in primary MSC derived from CLL patients and healthy donors. PI3Kδ inhibition in MSC using idelalisib or duvelisib significantly reduced their ability to support CLL migration and adhesion. These observations provide the first evidence that PI3Kδ is expressed and functional in CLL MSC.

Canadian evidence-based guideline for the first-line treatment of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (cll) is the most common adult leukemia in North America. In Canada, no unified national guideline exists for the front-line treatment of cll; provincial guidelines vary and are largely based on funding. A group of clinical experts from across Canada developed a national evidence-based treatment guideline to provide health care professionals with clear guidance on the first-line management of cll. Consensus recommendations based on available evidence are presented for the first-line treatment of cll.

Abstract 1891: Cross-resistance and synergy between idelalisib and bendamustine in chronic lymphocytic leukemia

Idelalisib (IDE) is an inhibitor of the δ isoform of PI3 kinase and has shown high activity in chronic lymphocytic leukemia (CLL) either when given alone or in combination with bendamustine (BEN) /rituximab (BR). In the present study, we have determined whether there is cross-resistance between BEN and IDE in primary CLL cells in vitro and whether synergy is observed upon combining these agents. In primary CLL cells in vitro, cross-resistance was not observed between BEN and IDE suggesting different modes of cytotoxicity. In contrast to BEN, sensitivity to IDE was not influenced by prior clinical treatment or the presence of a del 17p. Marked synergy in cytotoxicity was seen between BEN and IDE, which was paralleled by changes in γ-H2AX staining. These findings suggest that the synergistic antitumor effect was related to enhanced DNA damage by the drug combination. The degree of cytotoxic synergy varied and synergy was observed in some cases that were resistant to BEN or IDE, and those with del 17p. Synergy between BEN and IDE was also seen in the B cell lines, BJAB and I83, and in healthy donor peripheral blood mononuclear cells indicating that the phenomenon was not CLL-specific. To simulate the microenvironment, CLL cells were pre-stimulating with CD40L and IL4 prior to drug treatment. Interestingly this treatment caused the cells to become resistant to IDE, but BEN sensitivity was unaffected. However, combining BEN and IDE produced greater synergy than observed when cells were incubated without IL4/CD40. To examine the role of PI3Kδ for synergy, B cells from C57 BL/6 mice, both wild type and with non-functioning PI3Kδ protein, were exposed to BEN and/or IDE. Cells with the non-functioning PI3Kδ protein were more resistant to IDE than the wild-type cells and showed lesser synergy confirming the importance of this protein for the synergistic effect. In summary, these results confirm that IDE can be active against BEN-resistant CLL cells, while BEN may remain active against IDE-resistant samples, demonstrating different modes of anti-tumor activity. However, the unique yet inconsistent synergy seen between these two agents suggest an overlapping mechanism of action. Ongoing studies are evaluating the mechanism for this synergy.

Citation Format: Sara E. F. Kost, Ali Saleh, Edgard M. Mejia, Marina Mostafizar, Eric D. J. Bouchard, Versha Banerji, Aaron J. Marshall, Spencer B. Gibson, Sachin Katyal, James B. Johnston. Cross-resistance and synergy between idelalisib and bendamustine in chronic lymphocytic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1891.

Abstract 3515: Down the rabbit hole with structural effects of FK866 in primary CLL B cells

FK866 (Daporinad or APO866) is a specific inhibitor of NAMPT (nicotinamide phosphoribosyltransferase), a rate limiting enzyme involved in NAD generation. It is a prospective cancer treatment utilized in several clinical trials and has generated much interest. It has been previously demonstrated that FK866 (10nM) induces cell death in CLL patient derived B-cells (CLL-B cells) by early depletion of NAD (1 day after treatment) followed by a subsequent decrease in cellular ATP levels (2 days after treatment).

Upon further study we observed that CLL-B cells have structural changes after treatment with FK866 for either 6 or 18-20 hours via electron microscopy. There is a presence of bound structures as well as nuclear invaginations. These structures are only observed in cells that were treated with FK866 and not with any other drugs used (fludarabine, bendamustine, chlorambucil) nor with the DMSO or untreated controls.

We stained f-actin (a cytoskeletal protein) with FITC labelled phalloidin in CLL-B cells with and without FK866 treatment and then viewed with confocal microscopy to exclude the chance that these structures were artifacts. Changes in the f-actin were only observed in the FK866 treated cells. Phalloidin staining was performed at 6 and 18 hours. We observed holes in the f-actin framework that passed through the entire cell and in some instances, went through the nuclei too.

A comparison of the phalloidin staining was performed in non-CLL based cell lines that were known to be sensitive to treatment with FK866 though structural differences had not been observed at the same time points (6 and 18-20 hours). Two Ewing's sarcoma cell lines and two small cell lung cancer cell lines were used. All four cell lines showed no changes in the f-actin.

Labeled dextran beads were observed via confocal microscopy to be taken up more readily by the FK866 treated CLL -B cells as compared to the vehicle control. This would imply that the treated cells are actively removing nutrients from the environment.

A lysosome stain, LysoTracker, was employed to determine if there was any involvement of lysosomes in this phenomenon. No change was observed between the untreated, vehicle control and the FK866 treated CLL patient derived B-cells.

We were curious about the mitochondrial dynamics in the FK866 treated cells so they were stained with MitoTracker. We were able to detect mitochondria in the cytoplasm of the cells in all treatments but the FK866 treated cells displayed a more distinct punctate pattern. Interestingly, we also observed the mitochondria were appearing at or near the holes in the cytoskeleton.

As the FK866 treated cells are deprived of their NAD, the CLL cells may be undergoing macropinocytosis, an mTOR mediated phenomenon used by cells to extract nutrients from the environment. We have shown that FK866 causes an increase in 4EBP1 phosphorylation compared to controls.

In conclusion, FK866 may mediate macropinocytosis in CLL cells in an mTOR dependent manner.

Citation Format: Cheryl Peltier, Eileen McMillan-Ward, Elizabeth Henson, Nabanita Chatterje, Donna Hewitt, Danielle Desautels, Matthieu Bourrier, Cornelia Mutz, Iris Gehrke, Eric Bouchard, Heinrich Kovar, Shantanu Banerji, Spencer Gibson, Sara Israels, Versha Banerji. Down the rabbit hole with structural effects of FK866 in primary CLL B cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3515.

Associations between statin use and risk of non-Hodgkin lymphomas by subtype

Non-Hodgkin lymphomas (NHL) are a group of cancers with highly heterogeneous biology and clinical features. Statins are increasingly prescribed to prevent cardiovascular diseases. Early evidence shows a preventive effect of statins for some cancers, but their effect on NHL risk is unclear. We conducted a population-based nested case-control study involving 5,541 NHL cases and 27,315 controls matched for gender, age, place of residence and length of period of available prescription drug data. We assessed the use of statins prior to diagnosis (excluding the 12 months prior to the index date). We used conditional logistic regression models to estimate odds ratio (OR) and 95% confidence interval (CI) for use of any statin, adjusting for medical conditions, number of family physician visits for 5 years prior to index date, healthcare utilization, income and use of other medications. Over one-quarter of cases and controls were prescribed statins. Ever-use of any statin was associated with lower risk of Total NHL (OR = 0.82, 95% CI 0.76-0.89) and of certain subtypes including diffuse large B-cell lymphomas (DLBCL, OR = 0.77, 95% CI 0.65-0.92), plasma cell neoplasms (PCN, OR = 0.76, 95% CI 0.63-0.91) and other B-cell NHL (0.75, 0.59-0.95). Analysis by statin type suggested that the association was limited to high potency statin and lipophilic statin users. No clear duration or dose-response relationships were observed. Our findings provide evidence that statin use can reduce the risk of DLBCL and plasma cell lymphomas, but not other NHL types. Further studies are warranted to verify these associations and to examine the biological mechanisms.

EWS-FLI1 confers exquisite sensitivity to NAMPT inhibition in Ewing sarcoma cells

Ewing sarcoma (EwS) is the second most common bone cancer in children and adolescents with a high metastatic potential. EwS development is driven by a specific chromosomal translocation resulting in the generation of a chimeric EWS-ETS transcription factor, most frequently EWS-FLI1.

Nicotinamide adenine dinucleotide (NAD) is a key metabolite of energy metabolism involved in cellular redox reactions, DNA repair, and in the maintenance of genomic stability. This study describes targeting nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of NAD synthesis, by FK866 in EwS cells. Here we report that blocking NAMPT leads to exhaustive NAD depletion in EwS cells, followed by a metabolic collapse and cell death. Using conditional EWS-FLI1 knockdown by doxycycline-inducible shRNA revealed that EWS-FLI1 depletion significantly reduces the sensitivity of EwS cells to NAMPT inhibition. Consistent with this finding, a comparison of 7 EwS cell lines of different genotypes with 5 Non-EwS cell lines and mesenchymal stem cells revealed significantly higher FK866 sensitivity of EWS-ETS positive EwS cells, with IC₅₀ values mostly below 1nM.

Taken together, our data reveal evidence of an important role of the NAMPT-mediated NAD salvage pathway in the energy homeostasis of EwS cells and suggest NAMPT inhibition as a potential new treatment approach for Ewing sarcoma.

Expression of human monolysocardiolipin acyltransferase-1 improves mitochondrial function in Barth syndrome lymphoblasts

The mitochondrial polyglycerophospholipid cardiolipin (CL) is remodeled to obtain specific fatty acyl chains. This is predominantly accomplished by the transacylase enzyme tafazzin (TAZ). Barth syndrome (BTHS) patients with TAZ gene mutations exhibit impaired TAZ activity and loss in mitochondrial respiratory function. Previous studies identified monolysocardiolipin acyltransferase-1 (MLCL AT-1) as a mitochondrial enzyme capable of remodeling CL with fatty acid. In this study, we analyzed what relationship, if any, exists between TAZ and MLCL AT-1 with regard to CL remodeling and whether transfection of BTHS lymphoblasts with an MLCL AT-1 expression construct improves mitochondrial respiratory function. In healthy lymphoblasts, reduction in TAZ expression through TAZ RNAi transfection resulted in a compensatory increase in MLCL AT-1 mRNA, protein, and enzyme activity, but CL mass was unaltered. In contrast, BTHS lymphoblasts exhibited decreased TAZ gene and protein expression but in addition decreased MLCL AT-1 expression and CL mass. Transfection of BTHS lymphoblasts with MLCL AT-1 expression construct increased CL, improved mitochondrial basal respiration and protein leak, and decreased the proportion of cells producing superoxide but did not restore CL molecular species composition to control levels. In addition, BTHS lymphoblasts exhibited higher rates of glycolysis compared with healthy controls to compensate for reduced mitochondrial respiratory function. Mitochondrial supercomplex assembly was significantly impaired in BTHS lymphoblasts, and transfection of BTHS lymphoblasts with MLCL AT-1 expression construct did not restore supercomplex assembly. The results suggest that expression of MLCL AT-1 depends on functional TAZ in healthy cells. In addition, transfection of BTHS lymphoblasts with an MLCL AT-1 expression construct compensates, but not completely, for loss of mitochondrial respiratory function.

Metformin Is Not Associated with Incidence Risk of Non-Hodgkin Lymphomas among Diabetic Patients

Background: Several epidemiological studies have shown a positive association between diabetes and increased risk of non-Hodgkin lymphoma (NHL), but the effect of diabetic treatment drugs such as metformin on the risk is unknown.Methods: We conducted a population-based nested case-control study involving 878 NHL cases and 4,364 controls diagnosed with diabetes. Use of metformin and other medications before diagnosis and medical condition histories were assessed using administrative databases. We used conditional logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for use of metformin, adjusting for confounders.Results: Risk of total NHLs is not associated with ever use of metformin (OR, 0.93; 95% CI, 0.79-1.10) among diabetic patients. NHL subtypes were also not associated with metformin use.Conclusions: Metformin use is not associated with overall or subtype NHL risk among diabetic patients.Impact: NHLs are etiologically heterogeneous and larger scale studies are warranted to test the potential effect of metformin by NHL subtype. Cancer Epidemiol Biomarkers Prev; 27(5); 610-2. ©2018 AACR.