Richter's Syndrome (RS) of chronic lymphocytic leukemia (CLL) is typically chemoresistant, with a poor prognosis. We hypothesized that the oral Bcl-2 inhibitor venetoclax could sensitize RS to chemoimmunotherapy and improve outcomes. We conducted a single-arm, investigator-sponsored, phase 2 trial of venetoclax plus dose-adjusted rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (VR-EPOCH) to determine the rate of complete response (CR). Patients received R-EPOCH for 1 cycle, then after count recovery, accelerated daily venetoclax ramp-up to 400 mg, then VR-EPOCH for up to 5 more 21-day cycles. Responders received venetoclax maintenance or cellular therapy off-study. Twenty-six patients were treated, and 13 of 26 (50%) achieved CR, with 11 achieving undetectable bone marrow minimal residual disease for CLL. Three additional patients achieved partial response (overall response rate 62%). Median progression-free survival was 10.1 months, and median overall survival was 19.6 months. Hematologic toxicity included grade ≥3 neutropenia (65%) and thrombocytopenia (50%), with febrile neutropenia in 38%. No patients experienced tumor lysis syndrome with daily venetoclax ramp-up. VR-EPOCH is active in RS, with deeper, more durable responses than historical regimens. Toxicities from intensive chemoimmunotherapy and venetoclax were observed. Our data suggest that studies comparing venetoclax with chemoimmunotherapy to chemoimmunotherapy alone are warranted. (Funded by Genentech/AbbVie; ClinicalTrials.gov number, NCT03054896).

Summary Background Disease-related symptoms impair the quality of life of countless patients with chronic lymphocytic leukemia (CLL) who do not require systemic therapy. Currently available therapies are not specifically aimed at symptom control. Because stimulation of the B-cell receptor activates Janus kinase (JAK)-2 in CLL cells and the JAK2 inhibitor ruxolitinib improves symptoms of patients with myelofibrosis, we hypothesized that ruxolitinib would improve disease-related symptoms in CLL patients. Methods Ruxolitinib (10 mg twice daily) was administered to symptomatic CLL patients who did not require systemic therapy for CLL. Scores on the brief fatigue inventory (BFI), CLL module of the MD Anderson symptom inventory (MDASI) and symptom-associated interference in daily activities (interference score; IS), were assessed prior to treatment and after 3 months of treatment. Plasma cytokine/chemokine levels were measured at baseline and at 3 months. Findings Forty-one CLL patients (25 untreated and 16 previously treated) were enrolled. Thirty-two (78%) of the participants experienced ≥20% reduction in the average BFI score or in the average MDASI score. 59% of the participants had ≥2 units reduction in worst fatigue score in 24 hours as assessed by the BFI. The mean percentage reductions in BFI, MDASI, and IS scores were >42% (p<0.0001). Improvements in the three symptom scores correlated with reductions in levels of IL-6, C-reactive protein, CXCL10, osteopontin, TNF-α, ICAM-1/CD54, VCAM-1/CD106, and beta-2 microglobulin. Furthermore, treatment with ruxolitinib increased and then decreased lymphocyte counts to baseline levels or lower. Grade 3/4 cytopenias were recorded in three patients. Interpretation In CLL patients, ruxolitinib significantly improved disease-related symptoms, reduced cytokine and chemokine levels, and increased and then decreased lymphocyte counts, likely through mobilization followed by apoptosis of CLL cells. Further studies aimed at testing the therapeutic efficacy of ruxolitinib in CLL are warranted. Funding Supported by the Incyte Corp., MD Anderson Cancer Center Support Grant CA016672 and Award Number P01 CA049639 from the National Cancer Institute.

Introduction: Despite recent advances in CLL, the outcomes for Richter's Syndrome (RS) remain dismal. Complete response (CR) is observed only in about 20% of RS patients (pts) who receive chemoimmunotherapy such as dose-adjusted (da)-R-EPOCH, with short PFS/OS of <6 mo (Rogers et al., 2018). The oral Bcl-2 inhibitor venetoclax (ven) had a 43% response rate in RS (Davids et al., 2017).Here, we report for the first time on an ongoing study of ven + da-R- EPOCH in RS.Methods: This is a single-arm, phase 2, investigator sponsored trial of ven + da-R-EPOCH for RS (NCT03054896) open in the CLL Research Consortium (CRC) at 3 US sites. We treated CLL pts with biopsyconfirmed DLBCL transformation with R-EPOCH for 1 cycle, then after count recovery with accelerated inpatient daily ven ramp-up (20/50/100/200/400 mg), then ven + da-R-EPOCH for up to 5 additional 21d cycles (ven 400 mg qd, d1-10 of each cycle). Responders then received alloHCT or daily ven 400 mg qd maintenance in 28d cycles. Response by Lugano criteria with PET/CT, toxicity by CTCAE v4.03.134 ABSTRACT Angeles, CA, United States; 14 On assignment to PD Clinical Oncology, Introduction: BCL2 and BCL2 plus MYC overexpression, and coexisting BCL2 and MYC translocation (double-hit [DH]) are associated with poor outcomes in DLBCL. Ven, a highly selective BCL2 ABSTRACT

8004 Background: While therapeutic options for CLL have improved, patients (pts) who develop Richter’s Syndrome (RS) still have a poor prognosis. Chemoimmunotherapy regimens such as R-EPOCH lead to CR in about 20% of RS pts, but PFS/OS is typically < 6 mo. The oral Bcl-2 inhibitor venetoclax (ven) had a 43% single agent response rate in RS. Here, we report the results of a phase 2 study of VR-EPOCH in RS. Methods: This is a single-arm, phase 2, IST of VR-EPOCH for RS (NCT03054896) at 3 US sites. CLL pts with biopsy-confirmed DLBCL were treated with R-EPOCH for 1 cycle, then after count recovery underwent accelerated inpatient ven daily ramp-up (20/50/100/200/400 mg), then ven + R-EPOCH for up to 5 more 21d cycles (ven 400 mg qd, d1-10 each cycle). Responders went to alloHCT or to continuous daily ven 400 mg maintenance. Response evaluation by Lugano criteria with PET/CT. Results: As of the data cut on 2/3/2020, the study is fully enrolled with 27 pts. Median age: 63 yrs (range 49-77). CLL features: 26% del(17p); 44% complex karyotype; 48% IGHV unmutated; 41% TP53 and 15% NOTCH1 mutation. Median prior CLL treatments: 2 (range 0-5, prior ibrutinib [n = 8], ven [n = 2], and PI3Ki [n = 2]) with 6 untreated CLL pts. Median # ven + R-EPOCH cycles: 4 (range 0-6). 5 pts had dose de-escalation of R-EPOCH, 1 pt had dose escalation. ≥Gr 3 heme tox: neutropenia (58%), anemia (50%), thrombocytopenia (50%). ≥Gr 3 non-heme tox in > 15% of pts: febrile neutropenia (38%) and hypophosphatemia (23% each). No pts had TLS with daily ven ramp-up. Infections: pneumonia (n = 4), sepsis during C1 of R-EPOCH prior to starting ven (n = 3), enterocolitis (n = 3), sinusitis (n = 2), and 1 pt each with influenza A and norovirus. 10 pts have died, including 7 due to disease progression (2 during C1 before ven), and 1 each due to sepsis, sudden death, and GVHD post-alloHCT. In ITT analysis, 16 responded (ORR 59%); 13/27 (48%) had CR as best response, all with undetectable bone marrow MRD for CLL. Six pts were not evaluable for efficacy of the combo (5 had toxicity in C1 and never started ven, 1 withdrew after C1). In the 21 pts who started combo therapy, the ORR was 76%, CR rate 62%. Only 1 pt with CR has progressed. The pt on longest ven maintenance is in CR 2 years post chemo. 8 pts went to alloHCT, with pts still in CR now up to 2.5 yrs post-alloHCT. With a median follow-up of 9.3 mo (range 0.6-30), median PFS and OS are both 16.3 mo. Conclusions: VR-EPOCH is active for RS. Expected toxicities from intensive chemoimmunotherapy and ven were seen, but daily ven ramp-up was feasible. The 48% CR rate and median PFS of 16.3 mo are favorable in the context of historical results. Clinical trial information: NCT03054896 .

No abstract