ABSTRACT
BACKGROUND: New treatments have improved outcomes for patients with relapsed chronic lymphocytic leukemia (CLL), but complete remissions remain uncommon. Venetoclax has a distinct mechanism of action; it targets BCL2, a protein central to the survival of CLL cells. METHODS: We conducted a phase 1 dose-escalation study of daily oral venetoclax in patients with relapsed or refractory CLL or small lymphocytic lymphoma (SLL) to assess safety, pharmacokinetic profile, and efficacy. In the dose-escalation phase, 56 patients received active treatment in one of eight dose groups that ranged from 150 to 1200 mg per day. In an expansion cohort, 60 additional patients were treated with a weekly stepwise ramp-up in doses as high as 400 mg per day. RESULTS: The majority of the study patients had received multiple previous treatments, and 89% had poor prognostic clinical or genetic features. Venetoclax was active at all dose levels. Clinical tumor lysis syndrome occurred in 3 of 56 patients in the dose-escalation cohort, with one death. After adjustments to the dose-escalation schedule, clinical tumor lysis syndrome did not occur in any of the 60 patients in the expansion cohort. Other toxic effects included mild diarrhea (in 52% of the patients), upper respiratory tract infection (in 48%), nausea (in 47%), and grade 3 or 4 neutropenia (in 41%). A maximum tolerated dose was not identified. Among the 116 patients who received venetoclax, 92 (79%) had a response. Response rates ranged from 71 to 79% among patients in subgroups with an adverse prognosis, including those with resistance to fludarabine, those with chromosome 17p deletions (deletion 17p CLL), and those with unmutated IGHV. Complete remissions occurred in 20% of the patients, including 5% who had no minimal residual disease on flow cytometry. The 15-month progression-free survival estimate for the 400-mg dose groups was 69%. CONCLUSIONS: Selective targeting of BCL2 with venetoclax had a manageable safety profile and induced substantial responses in patients with relapsed CLL or SLL, including those with poor prognostic features. (Funded by AbbVie and Genentech; ClinicalTrials.gov number, NCT01328626.).
Subject(s)
Antineoplastic Agents/administration & dosage , Bridged Bicyclo Compounds, Heterocyclic/administration & dosage , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors , Sulfonamides/administration & dosage , Adult , Aged , Aged, 80 and over , Antineoplastic Agents/adverse effects , Antineoplastic Agents/pharmacokinetics , Bridged Bicyclo Compounds, Heterocyclic/adverse effects , Bridged Bicyclo Compounds, Heterocyclic/pharmacokinetics , Disease-Free Survival , Dose-Response Relationship, Drug , Female , Humans , Male , Middle Aged , Recurrence , Remission Induction , Sulfonamides/adverse effects , Sulfonamides/pharmacokinetics , Tumor Lysis Syndrome/etiologyABSTRACT
BACKGROUND: Selective BCL2 inhibition with venetoclax has substantial activity in patients with relapsed or refractory chronic lymphocytic leukaemia. Combination therapy with rituximab enhanced activity in preclinical models. The aim of this study was to assess the safety, pharmacokinetics, and activity of venetoclax in combination with rituximab. METHODS: Adult patients with relapsed or refractory chronic lymphocytic leukaemia (according to the 2008 Modified International Workshop on CLL guidelines) or small lymphocytic lymphoma were eligible for this phase 1b, dose-escalation trial. The primary outcomes were to assess the safety profile, to determine the maximum tolerated dose, and to establish the recommended phase 2 dose of venetoclax when given in combination with rituximab. Secondary outcomes were to assess the pharmacokinetic profile and analyse efficacy, including overall response, duration of response, and time to tumour progression. Minimal residual disease was a protocol-specified exploratory objective. Central review of the endpoints was not done. Venetoclax was dosed daily using a stepwise escalation to target doses (200-600 mg) and then monthly rituximab commenced (375 mg/m2 in month 1 and 500 mg/m2 in months 2-6). Adverse events were graded according to the National Cancer Institute Common Terminology Criteria for adverse events version 4.0. Protocol-guided drug cessation was allowed for patients who achieved complete response (including complete response with incomplete marrow recovery) or negative bone marrow minimal residual disease. Analyses were done per protocol for all patients who commenced drug and included all patients who received at least one dose of venetoclax. Data were pooled across dose cohorts. Patients are still receiving therapy and follow-up is ongoing. The trial is registered at ClinicalTrials.gov, number NCT01682616. FINDINGS: Between Aug 6, 2012, and May 28, 2014, we enrolled 49 patients. Common grade 1-2 toxicities included upper respiratory tract infections (in 28 [57%] of 49 patients), diarrhoea (27 [55%]), and nausea (25 [51%]). Grade 3-4 adverse events occurred in 37 (76%) of 49 patients; most common were neutropenia (26 [53%]), thrombocytopenia (eight [16%]), anaemia (seven [14%]), febrile neutropenia (six [12%]), and leucopenia (six [12%]). The most common serious adverse events were pyrexia (six [12%]), febrile neutropenia (five [10%]), lower respiratory tract infection, and pneumonia (each three [6%]). Clinical tumour lysis syndrome occurred in two patients (resulting in one death) who initiated venetoclax at 50 mg. After enhancing tumour lysis syndrome prophylaxis measures and commencing venetoclax at 20 mg, clinical tumour lysis syndrome did not occur. The maximum tolerated dose was not identified; the recommended phase 2 dose of venetoclax in combination with rituximab was 400 mg. Overall, 42 (86%) of 49 patients achieved a response, including a complete response in 25 (51%) of 49 patients. 2 year estimates for progression-free survival and ongoing response were 82% (95% CI 66-91) and 89% (95% CI 72-96), respectively. Negative marrow minimal residual disease was attained in 20 (80%) of 25 complete responders and 28 (57%) of 49 patients overall. 13 responders ceased all therapy; among these all 11 minimal residual disease-negative responders remain progression-free off therapy. Two with minimal residual disease-positive complete response progressed after 24 months off therapy and re-attained response after re-initiation of venetoclax. INTERPRETATION: A substantial proportion of patients achieved an overall response with the combination of venetoclax and rituximab including 25 (51%) of 49 patients who achieved a complete response and 28 (57%) of 49 patients who achieved negative marrow minimal residual disease with acceptable safety. The depth and durability of responses observed with the combination offers an attractive potential treatment option for patients with relapsed or refractory chronic lymphocytic leukaemia and could allow some patients to maintain response after discontinuing therapy, a strategy that warrants further investigation in randomised studies. FUNDING: AbbVie Inc and Genentech Inc.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Drug Resistance, Neoplasm/drug effects , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Neoplasm Recurrence, Local/drug therapy , Salvage Therapy , Adult , Aged , Aged, 80 and over , Bridged Bicyclo Compounds, Heterocyclic/administration & dosage , Cohort Studies , Female , Follow-Up Studies , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Male , Maximum Tolerated Dose , Middle Aged , Neoplasm Grading , Neoplasm Recurrence, Local/pathology , Prognosis , Remission Induction , Rituximab/administration & dosage , Sulfonamides/administration & dosage , Survival RateABSTRACT
Tumor lysis syndrome (TLS) is an uncommon but potentially life-threatening complication associated with the treatment of some cancers. If left untreated, TLS may result in acute renal failure, cardiac dysrhythmia, neurologic complications, seizures, or death. Tumor lysis syndrome is most commonly observed in patients with hematologic malignancies with a high proliferation rate undergoing treatment with very effective therapies. In chronic lymphocytic leukemia (CLL), historically, TLS has been observed less often, owing to a low proliferation rate and slow response to chemotherapy. New targeted therapies have recently been approved in the treatment of CLL, including the oral kinase inhibitors, idelalisib and ibrutinib, and the B-cell lymphoma-2 protein inhibitor, venetoclax. Several others are also under development, and combination strategies of these agents are being explored. This review examines the diagnosis, prevention, and management of TLS and summarizes the TLS experience in CLL clinical trials with newer targeted agents. Overall, the risk of TLS is small, but the consequences may be fatal; therefore, patients should be monitored carefully. Therapies capable of eliciting rapid response and combination regimens are increasingly being evaluated for treatment of CLL, which may pose a higher risk of TLS. For optimal management, patients at risk for TLS require prophylaxis and close monitoring with appropriate tests and appropriate management to correct laboratory abnormalities, which allows for safe and effective disease control. IMPLICATIONS FOR PRACTICE: Tumor lysis syndrome (TLS) is a potentially fatal condition observed with hematologic malignancies, caused by release of cellular components in the bloodstream from rapidly dying tumor cells. The frequency and severity of TLS is partly dependent upon the biology of the disease and type of therapy administered. Novel targeted agents highly effective at inducing rapid cell death in chronic lymphocytic leukemia (CLL) may pose a risk for TLS in patients with tumors characterized by rapid growth, high tumor burden, and/or high sensitivity to treatment. In this review, prevention strategies and management of patients with CLL who develop TLS are described.
Subject(s)
Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Proto-Oncogene Proteins c-bcl-2/genetics , Tumor Lysis Syndrome/drug therapy , Antineoplastic Agents/therapeutic use , Bridged Bicyclo Compounds, Heterocyclic/therapeutic use , Disease Management , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/complications , Leukemia, Lymphocytic, Chronic, B-Cell/prevention & control , Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors , Purines/therapeutic use , Quinazolinones/therapeutic use , Risk Factors , Sulfonamides/therapeutic use , Tumor Burden , Tumor Lysis Syndrome/complications , Tumor Lysis Syndrome/diagnosis , Tumor Lysis Syndrome/prevention & controlABSTRACT
BACKGROUND: Deletion of chromosome 17p (del[17p]) in patients with chronic lymphocytic leukaemia confers very poor prognosis when treated with standard chemo-immunotherapy. Venetoclax is an oral small-molecule BCL2 inhibitor that induces chronic lymphocytic leukaemia cell apoptosis. In a previous first-in-human study of venetoclax, 77% of patients with relapsed or refractory chronic lymphocytic leukaemia achieved an overall response. Here we aimed to assess the activity and safety of venetoclax monotherapy in patients with relapsed or refractory del(17p) chronic lymphocytic leukaemia. METHODS: In this phase 2, single-arm, multicentre study, we recruited patients aged 18 years and older with del(17p) relapsed or refractory chronic lymphocytic leukaemia (as defined by 2008 Modified International Workshop on Chronic Lymphocytic Leukemia guidelines) from 31 centres in the USA, Canada, UK, Germany, Poland, and Australia. Patients started once daily venetoclax with a weekly dose ramp-up schedule (20, 50, 100, 200, 400 mg) over 4-5 weeks. Patients were then given daily 400 mg continuous dosing until disease progression or discontinuation for another reason. The primary endpoint was the proportion of patients achieving an overall response, assessed by an independent review committee. Activity and safety analyses included all patients who received at least one dose of study drug (per protocol). This study is registered with ClinicalTrials.gov, number NCT01889186. Follow-up is ongoing, and patients are still receiving treatment. FINDINGS: Between May 27, 2013, and June 27, 2014, 107 patients were enrolled into the study. At a median follow-up of 12·1 months (IQR 10·1-14·2), an overall response by independent review was achieved in 85 (79·4%; 95% CI 70·5-86·6) of 107 patients. The most common grade 3-4 adverse events were neutropenia (43 [40%]), infection (21 [20%]), anaemia (19 [18%]), and thrombocytopenia (16 [15%]). Serious adverse events occurred in 59 (55%) patients, irrespective of their relationship to treatment, with the most common (≥5% of patients) being pyrexia and autoimmune haemolytic anaemia (seven [7%] each), pneumonia (six [6%]), and febrile neutropenia (five [5%]). 11 patients died in the study within 30 days of the last dose of venetoclax; seven due to disease progression and four from an adverse event (none assessed as treatment related). INTERPRETATION: Results of this trial show that venetoclax monotherapy is active and well tolerated in patients with relapsed or refractory del(17p) chronic lymphocytic leukaemia, providing a new therapeutic option for this very poor prognosis population. Additionally, in view of the distinct mechanism-of-action of venetoclax, combinations or sequencing with other novel targeted agents should be investigated to further advance treatment of del(17p) chronic lymphocytic leukaemia. FUNDING: AbbVie and Genentech.
Subject(s)
Antineoplastic Agents/therapeutic use , Bridged Bicyclo Compounds, Heterocyclic/therapeutic use , Chromosome Deletion , Chromosomes, Human, Pair 17/genetics , Drug Resistance, Neoplasm/drug effects , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Neoplasm Recurrence, Local/drug therapy , Salvage Therapy , Sulfonamides/therapeutic use , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Male , Middle Aged , Neoplasm Recurrence, Local/genetics , Neoplasm Recurrence, Local/pathology , Neoplasm Staging , Prognosis , Survival RateABSTRACT
Background: Artificial intelligence (AI) has the potential to reshape medical practice and the delivery of healthcare. Online discussions surrounding AI's utility in these domains are increasingly emerging, likely due to considerable interest from healthcare practitioners, medical technology developers, and other relevant stakeholders. However, many practitioners and medical students report limited understanding and familiarity with AI. Objective: To promote research, events, and resources at the intersection of AI and medicine for the online medical community, we created a Twitter-based campaign using the hashtag #MedTwitterAI. Methods: In the present study, we analyze the use of #MedTwitterAI by tracking tweets containing this hashtag posted from 26th March, 2019 to 26th March, 2021, using the Symplur Signals hashtag analytics tool. The full text of all #MedTwitterAI tweets was also extracted and subjected to a natural language processing analysis. Results: Over this time period, we identified 7,441 tweets containing #MedTwitterAI, posted by 1,519 unique Twitter users which generated 59,455,569 impressions. The most common identifiable locations for users including this hashtag in tweets were the United States (378/1,519), the United Kingdom (80/1,519), Canada (65/1,519), India (46/1,519), Spain (29/1,519), France (24/1,519), Italy (16/1,519), Australia (16/1,519), Germany (16/1,519), and Brazil (15/1,519). Tweets were frequently enhanced with links (80.2%), mentions of other accounts (93.9%), and photos (56.6%). The five most abundant single words were AI (artificial intelligence), patients, medicine, data, and learning. Sentiment analysis revealed an overall majority of positive single word sentiments (e.g., intelligence, improve) with 230 positive and 172 negative sentiments with a total of 658 and 342 mentions of all positive and negative sentiments, respectively. Most frequently mentioned negative sentiments were cancer, risk, and bias. Most common bigrams identified by Markov chain depiction were related to analytical methods (e.g., label-free detection) and medical conditions/biological processes (e.g., rare circulating tumor cells). Conclusion: These results demonstrate the generated considerable interest of using #MedTwitterAI for promoting relevant content and engaging a broad and geographically diverse audience. The use of hashtags in Twitter-based campaigns can be an effective tool to raise awareness of interdisciplinary fields and enable knowledge-sharing on a global scale.
Subject(s)
Social Media , Artificial Intelligence , Brazil , Germany , Humans , Spain , United StatesABSTRACT
In the congestive heart failure state, autonomic dysregulation involves an increase in sympathetic tone and decrease in parasympathetic tone and is associated with increased mortality. It is possible that augmentation of the parasympathetic nervous system (PNS) with pharmacologic therapy may lead to improved symptoms and/or clinical outcomes. There are several new and established pharmacologic interventions that have been studied for their effect on the PNS, including antagonists of the renin-angiotensin system, beta-adrenergic antagonists, digoxin, and vasodilators. In this review, we discuss the current status of the published literature on pharmacologic influences on the PNS by both conventional and experimental drugs targeting heart failure as well as drugs that more directly influence vagal tone. While these analyses have been largely limited to putative surrogates for clinical outcomes like heart rate variability, and it is often difficult to differentiate between indirect and direct pharmacologic effects on the PNS, significant insight into potential mechanisms of action can be derived. The future evaluation of drugs in development for heart failure treatment should include a careful, scientifically sound exploration of the potential impact of the intervention on PNS activity.
Subject(s)
Heart Failure/drug therapy , Parasympathetic Nervous System/drug effects , Vagus Nerve/drug effects , Cardiotonic Agents/therapeutic use , Heart Rate/drug effects , Humans , Renin-Angiotensin System/drug effects , Vagus Nerve StimulationABSTRACT
Background: Inconsistencies in information on safety of medicine use during pregnancy and lactation can result in sub-optimal treatment for pregnant and lactating women, risks to the fetus or child and unnecessary weaning off breastfeeding. The objective of this study was to analyze information discrepancies regarding medicine use during pregnancy and lactation between on-line sources for patients and health care professionals (HCPs) in four European languages.Research design and methods: The medicines analyzed were ibuprofen, ondansetron, olanzapine, fingolimod, methylphenidateâ¯and adalimumab. Recommendations were classified into different data source categories, for patients and for HCPs, and compared between the data source categories for each medicine and language.Results: For patients, 11/24 (46%) and 4/24 (17%) comparisons of the pregnancy and lactation recommendations, respectively, were consistent between all sources. The corresponding figures for HCP-sources were 13/24 (54%) and 5/24 (21%). Regulatory sources had generally more restrictive recommendations. Teratology Information Services (TIS) centers' recommendations for medicine use during pregnancy and lactation were consistent in 25/27 (93%) and 15/22 (68%) of cases respectively.Conclusion: Discrepancies between online information sources regarding medicine use during pregnancy and lactation are common, especially for lactation. TIS centers recommendations were more aligned. Additional work is needed to harmonize information within and between countries to avoid conflicting messages.
Subject(s)
Drug Information Services/standards , Drug-Related Side Effects and Adverse Reactions/prevention & control , Internet/standards , Breast Feeding , Drug Information Services/statistics & numerical data , Drug-Related Side Effects and Adverse Reactions/etiology , Female , Humans , Internet/statistics & numerical data , Lactation , Patient Education as Topic/methods , Patient Education as Topic/standards , PregnancyABSTRACT
Purpose: The oral BCL-2 inhibitor venetoclax is an effective therapy for patients with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL), including disease with high-risk genomic features such as chromosome 17p deletion [del(17p)] or progressive disease following B-cell receptor pathway inhibitors.Patients and Methods: We conducted a comprehensive analysis of the safety of 400 mg daily venetoclax monotherapy in 350 patients with CLL using an integrated dataset from three phase I/II studies.Results: Median age was 66 years and 60% had del(17p). Patients had received a median of three prior therapies (range: 0-15); 42% previously received ibrutinib or idelalisib. Median duration of exposure to venetoclax was 16 months (0-56). In the pooled analysis, the most common adverse events (AE) of any grade were diarrhea (41%), neutropenia (40%), nausea (39%), anemia (31%), fatigue (28%), and upper respiratory tract infection (25%). The most common grade 3/4 AEs were neutropenia (37%), anemia (17%), and thrombocytopenia (14%). With the current 5-week ramp-up dosing, the incidence of laboratory TLS was 1.4% (2/166), none had clinical sequelae, and all of these patients were able to ramp-up to a daily dose of 400 mg. Grade 3/4 neutropenia was manageable with growth factor support and dose adjustments; the incidence of serious infections in these patients was 15%. Ten percent of patients discontinued venetoclax due to AEs and 8% died while on study, with the majority of deaths in the setting of disease progression.Conclusions: Venetoclax as a long-term continuous therapy is generally well tolerated in patients with R/R CLL when initiated with the current treatment algorithm. Clin Cancer Res; 24(18); 4371-9. ©2018 AACR.
Subject(s)
Bridged Bicyclo Compounds, Heterocyclic/therapeutic use , Drug-Related Side Effects and Adverse Reactions/classification , Gastrointestinal Tract/drug effects , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Sulfonamides/therapeutic use , Adult , Aged , Aged, 80 and over , Bridged Bicyclo Compounds, Heterocyclic/administration & dosage , Bridged Bicyclo Compounds, Heterocyclic/adverse effects , Chromosome Deletion , Chromosomes, Human, Pair 17/genetics , Clinical Trials, Phase I as Topic , Clinical Trials, Phase II as Topic , Drug-Related Side Effects and Adverse Reactions/pathology , Female , Gastrointestinal Tract/pathology , Gene Expression Regulation, Neoplastic/drug effects , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Male , Middle Aged , Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors , Proto-Oncogene Proteins c-bcl-2/genetics , Smith-Magenis Syndrome/drug therapy , Smith-Magenis Syndrome/genetics , Smith-Magenis Syndrome/pathology , Sulfonamides/administration & dosage , Sulfonamides/adverse effects , Treatment Outcome , Tumor Suppressor Protein p53/geneticsABSTRACT
Purpose Venetoclax is an orally bioavailable B-cell lymphoma 2 inhibitor. US Food and Drug Administration and European Medicines Agency approval for patients with 17p deleted relapsed/refractory chronic lymphocytic leukemia [del(17p) CLL] was based on results from 107 patients. An additional 51 patients were enrolled in a safety expansion cohort. Extended analysis of all enrolled patients, including the effect of minimal residual disease (MRD) negativity on outcome, is now reported. Patients and Methods Overall, 158 patients with relapsed/refractory or previously untreated (n = 5) del(17p) CLL received venetoclax 400 mg per day after an initial dose ramp up. Responses were based on 2008 International Workshop on Chronic Lymphocytic Leukemia criteria, with monthly physical exams and blood counts. Computed tomography scan was mandatory at week 36, after which assessment made was by clinical evaluation. Marrow biopsy was performed when complete remission was suspected. MRD was assessed by flow cytometry. Results Patients had a median of two prior therapies (range, zero to 10 therapies), 71% had TP53 mutation, and 48% had nodes that were ≥ 5 cm. Median time on venetoclax was 23.1 months (range, 0 to 44.2 months) and median time on study was 26.6 months (range, 0 to 44.2 months). For all patients, investigator-assessed objective response rate was 77% (122 of 158 patients; 20% complete remission) and estimated progression-free survival at 24 months was 54% (95% CI, 45% to 62%). For 16 patients who received prior kinase inhibitors, objective response rate was 63% (10 of 16 patients) and 24-month progression-free survival estimate was 50% (95% CI, 25% to 71%). By intent-to-treat analysis, 48 (30%) of 158 patients achieved MRD below the cutoff of 10-4 in blood. Common grade 3 and 4 adverse events were hematologic and managed with supportive care and/or dose adjustments. Conclusion Venetoclax achieves durable responses and was well tolerated in patients with del(17p) CLL. A high rate of blood MRD < 10-4 was achieved in this high-risk population.
Subject(s)
Bridged Bicyclo Compounds, Heterocyclic/administration & dosage , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Smith-Magenis Syndrome/pathology , Sulfonamides/administration & dosage , Administration, Oral , Adult , Aged , Aged, 80 and over , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/adverse effects , Antineoplastic Agents/pharmacokinetics , Bridged Bicyclo Compounds, Heterocyclic/adverse effects , Bridged Bicyclo Compounds, Heterocyclic/pharmacokinetics , Chromosome Deletion , Chromosomes, Human, Pair 17/genetics , Female , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/metabolism , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Male , Middle Aged , Neoplasm, Residual/pathology , Smith-Magenis Syndrome/genetics , Sulfonamides/adverse effects , Sulfonamides/pharmacokineticsABSTRACT
Purpose B-cell leukemia/lymphoma-2 (BCL-2) overexpression is common in many non-Hodgkin lymphoma (NHL) subtypes. A phase I trial in patients with NHL was conducted to determine safety, pharmacokinetics, and efficacy of venetoclax, a selective, potent, orally bioavailable BCL-2 inhibitor. Patients and Methods A total of 106 patients with relapsed or refractory NHL received venetoclax once daily until progressive disease or unacceptable toxicity at target doses from 200 to 1,200 mg in dose-escalation and safety expansion cohorts. Treatment commenced with a 3-week dose ramp-up period for most patients in dose-escalation cohorts and for all patients in safety expansion. Results NHL subtypes included mantle cell lymphoma (MCL; n = 28), follicular lymphoma (FL; n = 29), diffuse large B-cell lymphoma (DLBCL; n = 34), DLBCL arising from chronic lymphocytic leukemia (Richter transformation; n = 7), Waldenström macroglobulinemia (n = 4), and marginal zone lymphoma (n = 3). Venetoclax was generally well tolerated. Clinical tumor lysis syndrome was not observed, whereas laboratory tumor lysis syndrome was documented in three patients. Treatment-emergent adverse events were reported in 103 patients (97%), a majority of which were grade 1 to 2 in severity. Grade 3 to 4 events were reported in 59 patients (56%), and the most common were hematologic, including anemia (15%), neutropenia (11%), and thrombocytopenia (9%). Overall response rate was 44% (MCL, 75%; FL, 38%; DLBCL, 18%). Estimated median progression-free survival was 6 months (MCL, 14 months; FL, 11 months; DLBCL, 1 month). Conclusion Selective targeting of BCL-2 with venetoclax was well tolerated, and single-agent activity varied among NHL subtypes. We determined 1,200 mg to be the recommended single-agent dose for future studies in FL and DLBCL, with 800 mg being sufficient to consistently achieve durable response in MCL. Additional investigations including combination therapy to augment response rates and durability are ongoing.