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• FCR-treated chronic lymphocytic leukemia patients with mutated IGHV gene achieve long-term PFS, with a plateau on the PFS curve.• MRD-negativity posttreatment is highly predictive of longterm PFS, particularly in patients with mutated IGHV gene.Accurate identification of patients likely to achieve long-progression-free survival (PFS) after chemoimmunotherapy is essential given the availability of less toxic alternatives, such as ibrutinib. Fludarabine, cyclophosphamide, and rituximab (FCR) achieved a high response rate, but continued relapses were seen in initial reports. We reviewed the original 300 patient phase 2 FCR study to identify long-term disease-free survivors. Minimal residual disease (MRD) was assessed posttreatment by a polymerase chain reaction-based ligase chain reaction assay (sensitivity 0.01%). At the median follow-up of 12.8 years, PFS was 30.9% (median PFS, 6.4 years). The 12.8-year PFS was 53.9% for patients with mutated immunoglobulin heavy chain variable (IGHV) gene (IGHV-M) and 8.7% for patients with unmutated IGHV (IGHV-UM). 50.7% of patients with IGHV-M achieved MRD-negativity posttreatment; of these, PFS was 79.8% at 12.8 years. A plateau was seen on the PFS curve in patients with IGHV-M, with no relapses beyond 10.4 years in 42 patients (total follow-up 105.4 patient-years). On multivariable analysis, IGHV-UM (hazard ratio, 3.37 [2.18-5.21]; P < .001) and del(17p) by conventional karyotyping (hazard ratio, 7.96 [1.02-61.92]; P 5 .048) were significantly associated with inferior PFS. Fifteen patients with IGHV-M had 4-color MRD flow cytometry (sensitivity 0.01%) performed in peripheral blood, at a median of 12.8 years posttreatment (range, 9.5-14.7). All were MRD-negative. The high rate of very long-term PFS in patients with IGHV-M after FCR argues for the continued use of chemoimmunotherapy in this patient subgroup outside clinical trials; alternative strategies may be preferred in patients with IGHV-UM, to limit long-term toxicity. (Blood. 2016;127(3):303-309)

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Highlights d B-lymphoid cancer cells can escape to venetoclax by overexpressing MCL-1 d Modulation of AMPK/PKA axis and lymphoid transcription drive venetoclax resistance d Venetoclax resistance involves changes in cellular energy metabolism such as OXPHOS d Metabolic modulators can cooperate with venetoclax to overcome resistance

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Ibrutinib, an oral covalent inhibitor of Bruton’s tyrosine kinase, is an effective therapy for patients with chronic lymphocytic leukemia (CLL). To determine whether rituximab provides added benefit to ibrutinib, we conducted a randomized single-center trial of ibrutinib vs ibrutinib plus rituximab. Patients with CLL requiring therapy were randomized to receive 28-day cycles of once-daily ibrutinib 420 mg, either as a single agent (n = 104), or together with rituximab (375 mg/m2; n = 104), given weekly during cycle 1, then once per cycle until cycle 6. The primary end point was progression-free survival (PFS) in the intention-to-treat population. We enrolled 208 patients with CLL, 181 with relapsed CLL and 27 treatment-naive patients with high-risk disease (17p deletion or TP53 mutation). After a median follow-up of 36 months, the Kaplan-Meier estimates of PFS were 86% (95% confidence interval [CI], 76.6-91.9) for patients receiving ibrutinib, and 86.9% (95% CI, 77.3-92.6) for patients receiving ibrutinib plus rituximab. Similarly, response rates were the same in both arms (overall response rate, 92%). However, time to normalization of peripheral blood lymphocyte counts and time to complete remission were shorter, and residual disease levels in the bone marrow were lower, in patients receiving ibrutinib plus rituximab. We conclude that the addition of rituximab to ibrutinib in relapsed and treatment-naive high-risk patients with CLL failed to show improvement in PFS. However, patients treated with ibrutinib plus rituximab reached their remissions faster and achieved significantly lower residual disease levels. Given these results, ibrutinib as single-agent therapy remains current standard-of-care treatment in CLL. This trial was registered at www.clinicaltrials.gov as #NCT02007044.

Background Ibrutinib is active in patients with relapsed/refractory (R/R) CLL. In patients treated with ibrutinib for R/R CLL, del(17p) identified by interphase fluorescence in situ hybridization (FISH) is associated with inferior progression-free survival, despite equivalent initial response rates. Del(17p) is frequently associated with complex metaphase karyotype (CKT); the prognostic significance of CKT in ibrutinib-treated patients has not been reported. Methods We reviewed 88 patients treated for R/R CLL at MD Anderson Cancer Center with investigational ibrutinib-based regimens from 2010–2013. Pre-treatment FISH and Lipopolysaccharide-stimulated metaphase cytogenetic analysis were performed on bone marrow. Results Adequate pre-treatment metaphase karyotype was available for 56/88 patients. Karyotype was complex in 21 of 56 cases; 17 of the 21 had del(17p) by FISH. Overall response rate, including partial remission with persistent lymphocytosis, was 94% with 17% complete responses. In multivariable analysis (MVA), only CKT was significantly associated with event-free survival (EFS) [HR 6.6 (1.7–25.6), p=0.006]. Fludarabine-refractory CLL [HR 6.9 (1.8–27.1), p=0.005] and CKT [HR 5.9 (1.6–22.2), p=0.008] were independently associated with inferior overall survival (OS) in MVA. Del(17p) by FISH was not significantly associated with EFS or OS in MVA. Conclusions CKT is a powerful predictor of outcome in ibrutinib-treated patients with R/R CLL and may be a stronger predictor of biological behavior than del(17p) by FISH. Given their relatively poor outcomes, patients with CKT are ideal candidates for studies of consolidative treatment strategies or novel treatment combinations.

The coronavirus disease 2019 (COVID-19) pandemic poses several challenges to the management of patients with leukemia. The biology of each leukemia and its corresponding treatment with conventional intensive chemotherapy, with or without targeted therapies (venetoclax, FLT3 inhibitors, IDH1/2 inhibitors, Bruton's tyrosine kinase inhibitors), introduce additional layers of complexity during COVID-19 highrisk periods. The knowledge about COVID-19 is accumulating rapidly. An important distinction is the prevalence of "exposure" versus "clinical infectivity," which determine the risk versus benefit of modifying potentially highly curative therapies in leukemia. At present, the rate of clinical infection is < 1-2% worldwide. With a mortality rate of 1-5% in CO-VID-19 patients in the general population and potentially of > 30% in patients with cancer, careful consideration should be given to the risk of COVID-19 in leukemia. Instead of reducing patient access to specialized cancer centers and modifying therapies to ones with unproven curative benefit, there is more rationale for less intensive, yet effective therapies that may require fewer clinic visits or hospitalizations. Here, we offer recommendations on the optimization of leukemia management during high-risk COVID-19 periods.