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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.

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 &beta, 2-microglobulin (&beta, 2-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&rsquo, 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.

Background:Chronic lymphocytic leukemia (CLL) is the most prevalent leukemia in North America with the majority of patients being over the age of 70 (Goede et al, 2014). CLL is a heterogeneous disease with some patients undergoing treatment at time of diagnosis, while others follow along a more indolent, asymptomatic course. When indicated, the choice of treatment is based on the patient's functional status, renal function and other comorbidities (Shanafelt, 2013). Previous studies have shown that unfit patients treated with Obinutuzumab plus Chlorambucil have shown prolongation of progression free survival and higher rates of complete response compared to other monoclonal based regimens (Goede et al, 2014). The aim of this study is to investigate the clinical use and uptake of Obinutuzumab in combination with Chlorambucil in a Canadian based population. Methods:All patients receiving Obinutuzumab were identified using the CLL CAISIS database. Then a retrospective chart review was conducted for patients approved for first-line antibody treatment with Obinutuzumab from January 1, 2014 to December 31, 2017. Data including patient characteristics, patterns of treatment, reported toxicities, response rates and survival data were collected and analyzed. This data was used to determine the overall safety and efficacy of this treatment regimen. Results: There were a total of 66 patients that met the inclusion criteria for this study. This cohort consisted of 54.5% males and 45.5% females, with a median age at diagnosis of 68 years (range: 46-94). Within this population 47 patients underwent florescence in situ hybridization testing, which identified 32 patients with chromosomal abnormalities. The immunoglobulin heavy chain variable region gene mutation was also tested in 41 patients, and identified 22 patients that were unmutated. At the time of treatment the median age was 73 (range: 55-98) with a median Cumulative Illness Rating Scale (CIRS) score of 8 (range: 3-15). Of the 66 patients who started treatment with Obinutuzumab, 50 patients (76%) achieved a partial response and 5 patients (8%) had no response. Of note, 21 patients (31.8%) discontinued treatment prior to completion of all six cycles due to cytopenias (4), other comorbidities (4), progression of CLL (2), decline in functional/mental status (2), patient request (2) and other (7). In regards to their treatment there was a high incidence of infusion related reactions (IRRs) on the first day of treatment, with 30 patients (45.5%) requiring intervention. There was a subset of 15 patients that had received low dose Chlorambucil prior to treatment with Obinutuzumab which resulted in a lower average lymphocyte count (38.1) and lower rate of IRRs (33%) compared to those with no prior Chlorambucil (average lymphocyte count: 66.5, rate of IRR: 42%). Due to toxicity and tolerability of Chlorambucil, dose reduction was observed in 37 patients (56%) throughout all six cycles of treatment. In the end, only 18 patients (27.3%) received all doses of Obinutuzumab and Chlorambucil while 37 patients (56%) received all doses of Obinutuzumab. Within the entire cohort, 12 patients have relapsed and 9 of these patients have required additional therapy. This relapse rate can be attributed to lack of response to Obinutuzumab (3), a 17p del (1), poor prognostic markers (5), and inadequate Obinutuzumab (1). Conclusion:In this current study, our results demonstrate that the majority of patients in this cohort were able to complete treatment with Obinutuzumab. Although our demographics were similar to previous studies, we found higher partial response rates (76%) likely due to differences in standards of practice, such as imaging studies after treatment. Disclosures Whiteside: Roche: Membership on an entity's Board of Directors or advisory committees, Other: teaching sessions. Dawe:AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees. Johnston:Roche: Other: unrestricted grant received in the past; Abbvie: Other: unrestricted grant received in the past; Teva: Other: unrestricted grant received in the past; Gilead: Other: unrestricted grant received in the past; Janssen: Other: unrestricted grant received in the past. Banerji:Roche: Other: Unrestricted grant received in the past; Janssen: Other: Unrestricted grant received in the past; Abbvie: Other: Unrestricted grant received in the past; Gilead: Other: Unrestricted grant received in the past; Teva: Other: Unrestricted grant received in the past.

Objective: Chronic lymphocytic leukemia (CLL) is one of the most common types of leukemia in adults. Altered mitochondrial metabolism has been shown to be involved in the pathogenesis of CLL. Nicotinamidephospho-ribosyltransferase (NAMPT) is a key enzyme in the nicotinamide adenine dinucleotide (NAD) salvage pathway. FK866 and GMX1778, chemical inhibitors of NAMPT, deplete cellular NAD and ATP levels and trigger apoptosis in CLL cells, suggesting NAMPT contributes to the prolonged survival of these cells. Venetoclax is an approved therapy for CLL and blocks the anti-apoptotic B-cell lymphoma-2 (Bcl-2) protein, leading to programmed cell death of CLL cells. The adenosine monophosphate-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) signaling axis senses the metabolic demands of cells and regulates mitochondrial function. Silent information regulator T1 (SIRT1) is a cytoplasmic enzyme that mediates NAD+-dependent deacetylation of target substrates. The importance of the AMPK/SIRT/PGC1α signaling pathway has to be explored yet in CLL. Venetoclax may trigger a switching off of AMPK and /or SIRT1 signaling leading to impaired PGC-1α expression/activity and diminished mitochondrial activity. The effects of these drugs on mitochondrial bioenergetics profile, cell viability, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) and protein levels of Bcl-2, AMPK, SIRT1, and PGC1α were analyzed. We hypothesize that venetoclax, along with FK866 and GMX1778, will alter CLL mitochondrial bioenergetics profiles and function, cell viability, and ROS levels through the involvement of the AMPK/SIRT/PGC1α signaling pathway and enable lower doses and profound effects for combination therapies rather than single agent therapy. Methods: A high resolution Oroboros Oxygraph 2K (Oroboros Instruments, Innsbruck, Austria), a Clarke-type oxygen electrode is used to measure mitochondrial respiration rates of CLL cells at 370C. Freshly isolated CLL cells (10 mil./ml) were added to the chamber in 2 ml of RPMI. After the measurement of basal respiration rates, the following chemicals were added: oligomycin (2uM), FCCP: carbonyl cyanide p-trifluoromethoxy phenyhydrazone (2.5-12.5 uM), and antimycin A (2 uM). Oxygen consumption rate is expressed in pmol oxygen/s/mil. cells. Protein levels in CLL cell lysates were determined by Western blotting. Cell viability, MMP, and ROS were assessed by Novocyte flow cytometer. Results: Primary CLL cells treated with 1.25 nM of venetoclax for 24 or 48h showed significantly decreased basal respiration rates, maximal respiration rates, and spare respiratory capacity compared to DMSO vehicle control. These parameters were also significantly affected by 1nM of FK866 or 1 nM of GMX1778 except basal respiration rates. The combination treatment of venetoclax with FK866 or GMX1778 for 24 or 48h significantly decreased all these bioenergetics parameters compared to each individual drug. MMP was not affected by these drug treatments and cell viability corresponded to the effect of the mitochondrial bioenergetics profile. ROS levels after 24 hours in venetoclax treated CLL cells were significantly increased compared to DMSO, any single agent or in combination. However, after 48 hours of treatment, increased ROS levels were not statistically significant compared to DMSO. Protein levels of Bcl-2, P-AMPK, AMPK, SIRT1, and PGC1α were decreased by venetoclax alone or in combination with FK866 or GMX1778. Conclusion: Venetoclax, FK866 and GMX1778 affected bioenergetics profiles in CLL cells at doses as low as 1.25 nM, 1nM, and 1 nM, respectively. The combined effect of these drugs on the mitochondrial bioenergetics profiles and cell viability is more profound than each NAMPT inhibitor agent alone. Protein levels of Bcl-2, AMPK, SIRT1, and PGC1α in venetoclax treated samples were reduced compared to DMSO and each single agent NAMPT inhibitor. These novel data suggest the involvement of the AMPK/SIRT/PGC1α signaling pathway to target mitochondrial metabolism and provide rational therapeutic combinations that may lead to reduced toxicity and increased drug efficacy in CLL. Disclosures Banerji: Roche: Other: Unrestricted grant received in the past; Janssen: Other: Unrestricted grant received in the past; Gilead: Other: Unrestricted grant received in the past; Abbvie: Other: Unrestricted grant received in the past; Teva: Other: Unrestricted grant received in the past.