This study investigated the activity of lenalidomide in patients with relapsed/refractory chronic lymphocytic leukemia (CLL). Lenalidomide was given at 10 mg daily with dose escalation up to 25 mg daily. Three patients (7%) achieved a complete response (CR), one a nodular partial remission, and 10 patients a partial remission (PR), for an overall response (OR) rate of 32%. Treatment with lenalidomide was associated with an OR rate of 31% in patients with 11q or 17p deletion, of 24% in patients with unmutated VH, and of 25% in patients with fludarabine-refractory disease. The most common toxicity was myelosuppression, and the median daily dose of lenalidomide tolerated was 10 mg. Plasma levels of angiogenic factors, inflammatory cytokines, and cytokine receptors were measured at baseline, day 7, and day 28. There was a dramatic increase in median interleukin (IL)-6, IL-10, IL-2, and tumor necrosis factor receptor-1 levels on day 7, whereas no changes were observed in median vascular endothelial growth factor levels (20 patients studied). According to our experience, lenalidomide given as a continuous treatment has antitumor activity in heavily pretreated patients with CLL. This trial is registered at http://www.clinicaltrials.gov as no. NCT00267059.

Purpose: Lenalidomide is an immunomodulatory drug active as salvage therapy for chronic lymphocytic leukemia (CLL). We combined lenalidomide with rituximab to improve response rates in patients with relapsed or refractory CLL.Patients and Methods: Fifty-nine adult patients (age 42 to 82 years) with relapsed or refractory CLL were enrolled onto a phase II study of lenalidomide and rituximab. Patients had received prior fludarabine-based therapy or chemoimmunotherapy. Rituximab (375 mg/m²intravenously) was administered weekly during cycle one and on day 1 of cycles three to 12. Lenalidomide was started on day 9 of cycle one at 10 mg orally and administered daily continuously. Each cycle was 28 days. Rituximab was administered for 12 cycles; lenalidomide could continue indefinitely if patients benefitted clinically.Results: The overall response rate was 66%, including 12% complete responses and 12% nodular partial remissions. Time to treatment failure was 17.4 months. Median overall survival has not been reached; estimated survival at 36 months is 71%. The most common grade 3 or 4 toxicity was neutropenia (73% of patients). Fourteen patients (24%) experienced a grade 3 to 4 infection or febrile episode. There was one episode of grade 3 tumor lysis; one patient experienced renal failure during the first cycle of therapy, and one venous thromboembolic event occurred during the study.Conclusion: The combination of lenalidomide and rituximab is active in patients with recurrent CLL and warrants further investigation.

PURPOSE: The combination of venetoclax and 5-azacitidine (5-AZA) for older or unfit patients with acute myeloid leukemia (AML) improves remission rates and survival compared with 5-AZA alone. We hypothesized that the addition of venetoclax to cladribine (CLAD)/low-dose araC (low-dose cytarabine [LDAC]) alternating with 5-AZA backbone may further improve outcomes for older patients with newly diagnosed AML. METHODS: This is a phase II study investigating the combination of venetoclax and CLAD/LDAC alternating with venetoclax and 5-AZA in older (≥ 60 years) or unfit patients with newly diagnosed AML. The primary objective was composite complete response (CR) rate (CR plus CR with incomplete blood count recovery); secondary end points were overall survival, disease-free survival (DFS), overall response rate, and toxicity. RESULTS: A total of 60 patients were treated; median age was 68 years (range, 57-84 years). By European LeukemiaNet, 23%, 33%, and 43% were favorable, intermediate, and adverse risk, respectively. Fifty-six of 60 evaluable patients responded (composite CR: 93%) and 84% were negative for measurable residual disease. There was one death (2%) within 4 weeks. With a median follow-up of 22.1 months, the median overall survival and DFS have not yet been reached. The most frequent grade 3/4 nonhematologic adverse events were febrile neutropenia (n = 33) and pneumonia (n = 14). One patient developed grade 4 tumor lysis syndrome. CONCLUSION: Venetoclax and CLAD/LDAC alternating with venetoclax and 5-AZA is an effective regimen among older or unfit patients with newly diagnosed AML. The rates of overall survival and DFS are encouraging. Further study of this non–anthracycline-containing backbone in younger patients, unfit for intensive chemotherapy, as well as comparisons to standard frontline therapies is warranted.

PURPOSE: Zanubrutinib is a potent, irreversible next-generation Bruton tyrosine kinase (BTK) inhibitor designed to maximize BTK occupancy and minimize off-target kinase inhibition. We hypothesized that complete/sustained BTK occupancy may improve efficacy outcomes and increased BTK specificity may minimize off-target inhibition-related toxicities. PATIENTS AND METHODS: ALPINE (ClinicalTrials.gov identifier: NCT03734016 ) is a global, randomized, open-label phase III study of zanubrutinib versus ibrutinib in patients with relapsed/refractory chronic lymphocytic leukemia. The primary end point was investigator-assessed overall response rate (ORR). The preplanned interim analysis was scheduled approximately 12 months after the first 415 patients were enrolled. RESULTS: Between November 1, 2018, and December 14, 2020, 652 patients were enrolled. We present the interim analysis of the first 415 enrolled patients randomly assigned to receive zanubrutinib (n = 207) or ibrutinib (n = 208). At 15 months of median follow-up, ORR (partial or complete response) was significantly higher with zanubrutinib (78.3%; 95% CI, 72.0 to 83.7) versus ibrutinib (62.5%; 95% CI, 55.5 to 69.1; two-sided P < .001). ORR was higher with zanubrutinib versus ibrutinib in subgroups with del(17p)/ TP53 mutations (80.5% v 50.0%) and del(11q) (83.6% v 69.1%); 12-month progression-free survival in all patients was higher with zanubrutinib (94.9%) versus ibrutinib (84.0%; hazard ratio, 0.40; 95% CI, 0.23 to 0.69). Atrial fibrillation rate was significantly lower with zanubrutinib versus ibrutinib (2.5% v 10.1%; two-sided P = .001). Rates of cardiac events, major hemorrhages, and adverse events leading to treatment discontinuation/death were lower with zanubrutinib. CONCLUSION: Zanubrutinib had a significantly higher ORR, lower atrial fibrillation rate, and improved progression-free survival and overall cardiac safety profile versus ibrutinib. These data support improved efficacy/safety outcomes with selective BTK inhibition.

BACKGROUND. Ibrutinib is an effective targeted therapy for patients with chronic lymphocytic leukemia (CLL) that inhibits Bruton’s tyrosine kinase (BTK), a kinase involved in B cell receptor signaling. METHODS. We used stable isotopic labeling with deuterated water ( ² H ₂ O) to measure directly the effects of ibrutinib on leukemia cell proliferation and death in 30 patients with CLL. RESULTS. The measured average CLL cell proliferation (“birth”) rate before ibrutinib therapy was 0.39% of the clone per day (range 0.17%–1.04%); this decreased to 0.05% per day (range 0%–0.36%) with treatment. Death rates of blood CLL cells increased from 0.18% per day (average, range 0%–0.7%) prior to treatment to 1.5% per day (range 0%–3.0%) during ibrutinib therapy, and they were even higher in tissue compartments. CONCLUSIONS. This study provides the first direct in vivo measurements to our knowledge of ibrutinib’s antileukemia actions, demonstrating profound and immediate inhibition of CLL cell proliferation and promotion of high rates of CLL cell death. TRIAL REGISTRATION. This trial was registered at clinicaltrials.gov (NCT01752426). FUNDING. This study was supported by a Cancer Center Support Grant (National Cancer Institute grant P30 CA016672), an NIH grant (CA081554) from the National Cancer Institute, MD Anderson’s Moon Shots Program in CLL, and Pharmacyclics, an AbbVie company.

The development and function of hematopoietic cells depends on complex signaling pathways that are mediated by numerous cytokines and their receptors. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is prominent both in normal hematopoiesis and in hematological malignancies. STATs are phosphorylated on tyrosine residues via JAK kinases and on serine residues by a variety of serine/threonine kinases. STATs then dimerize, translocate to the nucleus and bind DNA, initiating the transcription of target genes. STAT proteins mediate cell growth, differentiation, apoptosis, transformation, and other fundamental cell functions. Recently, mutations in the JAK2 gene driving the proliferation of the neoplastic clone have been identified in myeloproliferative disorders. In addition constitutive activation of the JAK-STAT pathway has been reported in various types of leukemias such as acute myelogenous leukemia, T-LGL leukemia, and multiple myeloma. This review describes the pathophysiological role of this pathway in hematological malignancies and the potential benefits of JAK-STAT inhibition.