Activity of venetoclax in patients with relapsed or refractory chronic lymphocytic leukaemia: analysis of the VENICE-1 multicentre, open-label, single-arm, phase 3b trial.

BACKGROUND: Most patients with chronic lymphocytic leukaemia progress after treatment or retreatment with targeted therapy or chemoimmunotherapy and have limited subsequent treatment options. Response levels to the single-agent venetoclax in the relapsed setting is unknown. We aimed to assess venetoclax activity in patients with or without previous B-cell receptor-associated kinase inhibitor (BCRi) treatment. METHODS: This multicentre, open-label, single-arm, phase 3b trial (VENICE-1) assessed activity and safety of venetoclax monotherapy in adults with relapsed or refractory chronic lymphocytic leukaemia, stratified by previous exposure to a BCRi. Eligible participants were aged 18 years or older with previously treated relapsed or refractory chronic lymphocytic leukaemia. Presence of del(17p) or TP53 aberrations and previous BCRi treatment were permitted. Patients received 5-week ramp-up to 400 mg of oral venetoclax once daily and were treated for up to 108 weeks, with 2 years follow-up after discontinuation, or optional extended access. The primary activity endpoint was complete remission rate (complete remission or complete remission with incomplete marrow recovery) in BCRi-naive patients. Analyses used the intent-to-treat (ie, all enrolled patients, which coincided with those who received at least one dose of venetoclax). This study was registered with ClinicalTrials.gov, NCT02756611, and is complete. FINDINGS: Between June 22, 2016, and March 11, 2022, we enrolled 258 patients with relapsed or refractory chronic lymphocytic leukaemia (180 [70%] were male; 252 [98%] were White; 191 were BCRi-naive and 67 were BCRi-pretreated). Median follow-up in the overall cohort was 49·5 months (IQR 47·2-54·1), 49·2 months (47·2-53·2) in the BCRi-naive group, and 49·7 months (47·4-54·3) in the BCRi-pretreated group. Of 191 BCRi-naive patients, 66 (35%; 95% CI 27·8-41·8) had complete remission or complete remission with incomplete marrow recovery. 18 (27%; 95% CI 16·8-39·1) of 67 patients in the BCRi-pretreated group had complete remission or complete remission with incomplete marrow recovery. Grade 3 or worse treatment-emergent adverse events were reported in 203 (79%) and serious adverse events were reported in 136 (53%) of 258 patients in the overall cohort. The most common treatment-emergent adverse event was neutropenia (96 [37%]) and the most common and serious adverse event was pneumonia (21 [8%]). There were 13 (5%) deaths reported due to adverse events; one of these deaths (autoimmune haemolytic anaemia) was possibly related to venetoclax. No new safety signals were identified. INTERPRETATION: These data demonstrate deep and durable responses with venetoclax monotherapy in patients with relapsed or refractory chronic lymphocytic leukaemia, including BCRi-pretreated patients, suggesting that venetoclax monotherapy is an effective strategy for treating BCRi-naive and BCRi-pretreated patients. FUNDING: AbbVie.

A Phase I study of the safety, pharmacokinetics and efficacy of navitoclax plus docetaxel in patients with advanced solid tumors.

Aim: This Phase I study investigated safety of navitoclax and docetaxel in patients (n = 41) with advanced solid tumors. Patients & methods: Two navitoclax plus docetaxel dosing schedules (21 and 28 days) were evaluated. Maximum tolerated dose, dose-limiting toxicities and preliminary antitumor activity were assessed. Results: Ten (24%) patients experienced dose-limiting toxicities; dose-escalation cohorts: n = 7 (21-day schedule: n = 5; 28-day schedule: n = 2) and 21-day expanded safety cohort: n = 3. Navitoclax 150-mg days 1-5 every 21 days with docetaxel 75 mg/m2 day 1 was the maximum tolerated dose and optimal schedule. Adverse events included thrombocytopenia (63%), fatigue (61%), nausea (59%) and neutropenia (51%). Four confirmed partial responses occurred. Conclusion: Navitoclax 150-mg orally once/day was safely administered with docetaxel. Myelosuppression limited dose escalation; antitumor activity was observed. Clinical trial registration: NCT00888108 (ClinicalTrials.gov).

Comprehensive Safety Analysis of Venetoclax Monotherapy for Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia.

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.

Efficacy and Biological Correlates of Response in a Phase II Study of Venetoclax Monotherapy in Patients with Acute Myelogenous Leukemia.

We present a phase II, single-arm study evaluating 800 mg daily venetoclax, a highly selective, oral small-molecule B-cell leukemia/lymphoma-2 (BCL2) inhibitor in patients with high-risk relapsed/refractory acute myelogenous leukemia (AML) or unfit for intensive chemotherapy. Responses were evaluated following revised International Working Group (IWG) criteria. The overall response rate was 19%; an additional 19% of patients demonstrated antileukemic activity not meeting IWG criteria (partial bone marrow response and incomplete hematologic recovery). Twelve (38%) patients had isocitrate dehydrogenase 1/2 mutations, of whom 4 (33%) achieved complete response or complete response with incomplete blood count recovery. Six (19%) patients had BCL2-sensitive protein index at screening, which correlated with time on study. BH3 profiling was consistent with on-target BCL2 inhibition and identified potential resistance mechanisms. Common adverse events included nausea, diarrhea and vomiting (all grades), and febrile neutropenia and hypokalemia (grade 3/4). Venetoclax demonstrated activity and acceptable tolerability in patients with AML and adverse features. SIGNIFICANCE: Venetoclax monotherapy demonstrated clinical activity in patients with AML (relapsed/refractory or unfit for intensive chemotherapy) with a tolerable safety profile in this phase II study. Predictive markers of response consistent with BCL2 dependence were identified. Clinical and preclinical findings provide a compelling rationale to evaluate venetoclax combined with other agents in AML. Cancer Discov; 6(10); 1106-17. ©2016 AACRSee related commentary by Pullarkat and Newman, p. 1082This article is highlighted in the In This Issue feature, p. 1069.

Safety, efficacy, and pharmacokinetics of navitoclax (ABT-263) in combination with irinotecan: results of an open-label, phase 1 study.

PURPOSE: The oral Bcl-2 inhibitor navitoclax demonstrated activity in solid and hematologic malignancies as monotherapy and in combination with other cytotoxic agents in preclinical and early clinical studies. We evaluated the safety, pharmacokinetics (PK), and antitumor activity of navitoclax plus irinotecan. METHODS: In this multicenter, open-label, phase 1 dose escalation study, adults with advanced solid tumors received navitoclax (starting dose 150 mg/day) in combination with 1 of 2 irinotecan schedules during a 21-day cycle: a once-every-3-week regimen (Q3W 180, 250, or 350 mg/m(2)) or a once-weekly regimen (QW 75 or 100 mg/m(2)). Enrollment occurred until a maximum tolerated dose (MTD) and/or recommended phase 2 dose (RPTD) was reached. RESULTS: All patients (Q3W, n = 14; QW, n = 17) were evaluable for safety, PK, and efficacy. The most common adverse event in both groups was diarrhea (Q3W 92.9 %; QW 76.5 %), which was the most frequent grade 3/grade 4 adverse event (Q3W 42.9 %; QW 29.4 %). The study was amended to exclude 4 UGT1A1*28 7/7 homozygous patients due to frequent irinotecan-related grade 3/grade 4 diarrhea and/or febrile neutropenia. No apparent PK interactions between navitoclax and irinotecan were observed. The MTD of the combination was exceeded in the Q3W group at the lowest dose administered. In the QW group, the MTD and RPTD for navitoclax were 150 mg when combined with irinotecan 75 mg/m(2). One patient in each group achieved a partial response. CONCLUSION: The RPTD of navitoclax in combination with irinotecan 75 mg/m(2) QW during a 21-day cycle was 150 mg in these heavily pretreated patients.

Safety, efficacy, and pharmacokinetics of navitoclax (ABT-263) in combination with erlotinib in patients with advanced solid tumors.

PURPOSE: Navitoclax (ABT-263), a novel, oral Bcl-2 inhibitor, enhances the antitumor effects of chemotherapy in vitro by lowering the apoptotic threshold. This phase I study (NCT01009073) evaluated the safety, pharmacokinetics, and preliminary antitumor activity of navitoclax combined with erlotinib in patients with advanced solid tumors. PATIENTS AND METHODS: An open-label dose escalation study included an arm evaluating navitoclax combined with erlotinib, which included a dose escalation cohort and a planned safety expansion cohort. Patients with documented cancers for whom erlotinib therapy was appropriate received erlotinib 150 mg orally once daily plus navitoclax 150 mg orally once daily, with navitoclax dose escalation via a continuous reassessment method model. RESULTS: Eleven patients were enrolled, including six patients with nonsmall cell lung cancer. Dose-limiting toxicities, most commonly diarrhea, were observed in 4 patients. Navitoclax dosing remained at 150 mg/day because the maximum tolerated dose was exceeded at this starting dose. The planned dose escalation did not occur; no recommended phase II dose (RPTD) was identified, and there was no safety expansion cohort. The most common treatment-related adverse events were diarrhea, nausea, vomiting, and decreased appetite. Pharmacokinetic analysis showed no apparent interactions between co-administered navitoclax and erlotinib. No objective responses were observed; the disease control rate was 27 % (95 % CI, 6-61 %). CONCLUSION: At the erlotinib and navitoclax doses administered, RPTD was not reached, but the safety profile of the combination was consistent with data from monotherapy studies. There were no apparent pharmacokinetic interactions between erlotinib and navitoclax. Three patients had stable disease.

Phase 1 study of the safety, pharmacokinetics, and antitumour activity of the BCL2 inhibitor navitoclax in combination with rituximab in patients with relapsed or refractory CD20+ lymphoid malignancies.

The oral BCL2 inhibitor navitoclax has moderate single-agent efficacy in chronic lymphocytic leukaemia (CLL) and minor activity in lymphoma in Phase 1 trials. Navitoclax synergizes with rituximab in preclinical models of B-cell lymphoid cancers. We report the safety, pharmacokinetics and clinical activity of this combination. Patients received navitoclax (200-325 mg) daily and four standard weekly doses of rituximab. Twenty-nine patients were enrolled across three dose-escalation cohorts and a safety expansion cohort (250 mg/d navitoclax). The combination was well tolerated. Common toxicities were mild diarrhoea (79%) and nausea (72%). Grade 4 thrombocytopenia occurred in 17% of patients (dose limiting at 325 mg/d). CD19(+) counts were severely reduced, while CD3(+) cells (~ 20%) and serum immunoglobulin M levels (~ 33%) were also reduced during the first year. The maximum tolerated dose for navitoclax in combination was 250 mg/d. Pharmacokinetic analyses revealed no apparent interactions between the drugs. The response rate in patients with follicular lymphoma was 9/12, including five complete responses. All five patients with CLL/small lymphocytic leukaemia achieved partial responses. One of nine patients with aggressive lymphoma responded. The addition of rituximab to navitoclax 250 mg/d is safe; the combination demonstrates higher response rates for low-grade lymphoid cancers than observed for either agent alone in previous Phase 1 trials.

A phase I safety and pharmacokinetic study of ABT-263 in combination with carboplatin/paclitaxel in the treatment of patients with solid tumors.

Bcl-2 family proteins are the key regulators of the intrinsic apoptotic pathway, controlling the point-of no-return and setting the threshold to engage the death machinery in response to chemical damage. Bcl-2 proteins have emerged as attractive targets for anti-cancer drug development. Navitoclax is a selective, potent, orally bioavailable, small molecule Bcl-2 inhibitor. Primary endpoints assessed the safety and pharmacokinetic (PK) interactions between navitoclax in combination with carboplatin/paclitaxel or paclitaxel alone in patients with solid tumors The study comprised two arms, one a combination of navitoclax with paclitaxel and carboplatin, the second with navitoclax and paclitaxel alone. Nineteen patients were enrolled in this study. The most frequently reported treatment-emergent AEs were alopecia (57.9 %), anemia (52.6 %), nausea (52.6 %), constipation (42.1 %), diarrhea (42.1 %), fatigue (42.1 %), neutropenia (36.8 %), thrombocytopenia (36.8 %), vomiting (31.6 %), decreased appetite (31.6 %), dehydration (26.3 %), and hypomagnesaemia (26.3 %). In the light of significant hematological and non-hematological toxicity the study was ended before de-escalation of navitoclax. Only one partial response was obtained at any dose tested, thus lowering doses could not have increased efficacy. It is the combination of toxicity with modest efficacy that led to discontinuation. No apparent PK interaction was observed between navitoclax and carboplatin or paclitaxel and the combination of navitoclax and paclitaxel had modest anti-tumor activity.

A phase I clinical trial of navitoclax, a targeted high-affinity Bcl-2 family inhibitor, in combination with gemcitabine in patients with solid tumors.

PURPOSE: To investigate the safety, optimal dosing, pharmacokinetics and clinical activity of a regimen of navitoclax (ABT-263) combined with gemcitabine in patients with solid tumors. EXPERIMENTAL DESIGN: Patients with solid tumors for which gemcitabine was deemed an appropriate therapy were enrolled into one of two different dosing schedules (21-day dosing schedule: navitoclax administered orally on days 1-3 and 8-10,; and gemcitabine 1,000 mg/m(2) on days 1 and 8; 28-day dosing schedule: navitoclax administrated orally on days 1-3, 8-10, and 15-17; and gemcitabine 1,000 mg/m(2) on days 1, 8 and 15). Navitoclax doses were escalated from 150 to 425 mg. An expanded safety cohort was conducted for the 21-day dosing schedule at the maximum tolerated dose (MTD) of navitoclax. RESULTS: Forty-six patients were enrolled at three U.S. centers. The most common adverse events included: hematologic abnormalities (thrombocytopenia, neutropenia, and anemia), liver enzyme elevations (ALT and AST), and gastrointestinal disturbances (diarrhea, nausea, and vomiting). Dose-limiting toxicities (DLTs) observed in cycle 1 were grade 4 thrombocytopenia (2 patients), grade 4 neutropenia (1 patient), and grade 3 AST elevation (2 patients). The MTD of navitoclax was 325 mg co-administered with gemcitabine 1,000 mg/m(2) for the 21-day schedule. No clinically significant pharmacokinetic drug-drug interactions were observed. There were no objective responses. Stable disease, reported at the end of cycle 2, was the best response in 54 % of evaluable patients (n = 39). CONCLUSIONS: The combination of navitoclax 325 mg with gemcitabine 1,000 mg/m(2) was generally well tolerated and exhibited a favorable safety profile in patients with advanced solid tumors.

Phase II study of single-agent navitoclax (ABT-263) and biomarker correlates in patients with relapsed small cell lung cancer.

PURPOSE: Bcl-2 is a critical regulator of apoptosis that is overexpressed in the majority of small cell lung cancers (SCLC). Nativoclax (ABT-263) is a potent and selective inhibitor of Bcl-2 and Bcl-x(L). The primary objectives of this phase IIa study included safety at the recommended phase II dose and preliminary, exploratory efficacy assessment in patients with recurrent and progressive SCLC after at least one prior therapy. EXPERIMENTAL DESIGN: Thirty-nine patients received navitoclax 325 mg daily, following an initial lead-in of 150 mg daily for 7 days. Study endpoints included safety and toxicity assessment, response rate, progression-free and overall survival (PFS and OS), as well as exploratory pharmacodynamic correlates. RESULTS: The most common toxicity associated with navitoclax was thrombocytopenia, which reached grade III-IV in 41% of patients. Partial response was observed in one (2.6%) patient and stable disease in 9 (23%) patients. Median PFS was 1.5 months and median OS was 3.2 months. A strong association between plasma pro-gastrin-releasing peptide (pro-GRP) level and tumor Bcl-2 copy number (R = 0.93) was confirmed. Exploratory analyses revealed baseline levels of cytokeratin 19 fragment antigen 21-1, neuron-specific enolase, pro-GRP, and circulating tumor cell number as correlates of clinical benefit. CONCLUSION: Bcl-2 targeting by navitoclax shows limited single-agent activity against advanced and recurrent SCLC. Correlative analyses suggest several putative biomarkers of clinical benefit. Preclinical models support that navitoclax may enhance sensitivity of SCLC and other solid tumors to standard cytotoxics. Future studies will focus on combination therapies.

Substantial susceptibility of chronic lymphocytic leukemia to BCL2 inhibition: results of a phase I study of navitoclax in patients with relapsed or refractory disease.

PURPOSE: BCL2 overexpression is a hallmark of chronic lymphocytic leukemia (CLL). The novel BH3 mimetic navitoclax (ABT-263) specifically inhibits BCL2 and related proteins BCL-x(l) and BCL-w, potently inducing apoptosis of CLL cells in vitro. A phase I trial in patients with CLL was conducted to evaluate the safety, pharmacokinetics, and biologic activity of oral navitoclax. PATIENTS AND METHODS: Twenty-nine patients with relapsed or refractory CLL received daily navitoclax for 14 days (10, 110, 200, or 250 mg/d; n = 15) or 21 days (125, 200, 250, or 300 mg/d; n = 14) of each 21-day cycle. Dose escalation decisions were informed by continual reassessment methodology. RESULTS: Lymphocytosis was reduced by more than 50% in 19 of 21 patients with baseline lymphocytosis. Among 26 patients treated with navitoclax ≥ 110 mg/d, nine (35%) achieved a partial response and seven maintained stable disease for more than 6 months. Median treatment duration was 7 months (range, 1 to ≥ 29 months). Median progression-free survival was 25 months. Activity was observed in patients with fludarabine-refractory disease, bulky adenopathy, and del(17p) CLL. Thrombocytopenia due to BCL-x(l) inhibition was the major dose-limiting toxicity and was dose-related. Low MCL1 expression and high BIM:MCL1 or BIM:BCL2 ratios in leukemic cells correlated with response. We determined that the navitoclax dose of 250 mg/d in a continuous dosing schedule was optimal for phase II studies. CONCLUSION: BCL2 is a valid therapeutic target in CLL, and its inhibition by navitoclax warrants further evaluation as monotherapy and in combination in this disease.

Phase I study of Navitoclax (ABT-263), a novel Bcl-2 family inhibitor, in patients with small-cell lung cancer and other solid tumors.

PURPOSE: Resistance to chemotherapy-induced apoptosis represents a major obstacle to cancer control. Overexpression of Bcl-2 is seen in multiple tumor types and targeting Bcl-2 may provide therapeutic benefit. A phase I study of navitoclax, a novel inhibitor of Bcl-2 family proteins, was conducted to evaluate safety, pharmacokinetics, and preliminary efficacy in patients with solid tumors. PATIENTS AND METHODS: Patients enrolled to intermittent dosing cohorts received navitoclax on day -3, followed by dosing on days 1 to 14 of a 21-day cycle. Patients on continuous dosing received a 1-week lead-in dose of 150 mg followed by continuous daily administration. Blood samples were collected for pharmacokinetic analyses, biomarker analyses, and platelet monitoring. RESULTS: Forty-seven patients, including 29 with small-cell lung cancer (SCLC) or pulmonary carcinoid, were enrolled between 2007 and 2008, 35 on intermittent and 12 on continuous dosing cohorts. Primary toxicities included diarrhea (40%), nausea (34%), vomiting (36%), and fatigue (34%); most were grade 1 or 2. Dose- and schedule-dependent thrombocytopenia was seen in all patients. One patient with SCLC had a confirmed partial response lasting longer than 2 years, and eight patients with SCLC or carcinoid had stable disease (one remained on study for 13 months). Pro-gastrin releasing peptide (pro-GRP) was identified as a surrogate marker of Bcl-2 amplification and changes correlated with changes in tumor volume. CONCLUSION: Navitoclax is safe and well tolerated, with dose-dependent thrombocytopenia as the major adverse effect. Preliminary efficacy data are encouraging in SCLC. Efficacy in SCLC and the utility of pro-GRP as a marker of treatment response will be further evaluated in phase II studies.

Navitoclax, a targeted high-affinity inhibitor of BCL-2, in lymphoid malignancies: a phase 1 dose-escalation study of safety, pharmacokinetics, pharmacodynamics, and antitumour activity.

BACKGROUND: Proteins of the BCL-2 family regulate clonal selection and survival of lymphocytes, and are frequently overexpressed in lymphomas. Navitoclax is a targeted high-affinity small molecule that inhibits the anti-apoptotic activity of BCL-2 and BCL-XL. We aimed to assess the safety and antitumour activity of navitoclax in patients with lymphoid tumours, and establish the drug's pharmacokinetic and pharmacodynamic profiles. METHODS: In this phase 1 dose-escalation study, patients (aged ≥18 years) with relapsed or refractory lymphoid malignancies were enrolled and treated at seven sites in the USA between November, 2006, and November, 2009. A modified Fibonacci 3+3 design was used to assign patients to receive oral navitoclax once daily by one of two dosing schedules: intermittently for the first 14 days of a 21-day cycle (14/21) at doses of 10, 20, 40, 80, 110, 160, 225, 315, or 440 mg/day; or continuously for 21 days of a 21-day cycle (21/21) at doses of 200, 275, 325, or 425 mg/day. Study endpoints were safety, maximum tolerated dose, pharmacokinetic profile, pharmacodynamic effects on platelets and T cells, and antitumour activity. This trial is registered with ClinicalTrials.gov, number NCT00406809. FINDINGS: 55 patients were enrolled (median age 59 years, IQR 51-67), 38 to receive the 14/21 dosing schedule, and 17 to receive the 21/21 dosing schedule. Common toxic effects included grade 1 or 2 anaemia (41 patients), infection (39), diarrhoea (31), nausea (29), and fatigue (21); and grade 3 or 4 thrombocytopenia (29), lymphocytopenia (18), and neutropenia (18). On the intermittent 14/21 schedule, dose-limiting toxic effects were hospital admissions for bronchitis (one) and pleural effusion (one), grade 3 increase in aminotransferases (one), grade 4 thrombocytopenia (one), and grade 3 cardiac arrhythmia (one). To reduce platelet nadir associated with intermittent 14/21 dosing, we assessed a 150 mg/day lead-in dose followed by a continuous 21/21 dosing schedule. On the 21/21 dosing schedule, two patients did not complete the first cycle and were excluded from assessment of dose-limiting toxic effects; dose-limiting toxic effects were grade 4 thrombocytopenia (one), grade 3 increase in aminotransferases (one), and grade 3 gastrointestinal bleeding (one). Navitoclax showed a pharmacodynamic effect on circulating platelets and T cells. Clinical responses occurred across the range of doses and in several tumour types. Ten of 46 patients with assessable disease had a partial response, and these responders had median progression-free survival of 455 days (IQR 40-218). INTERPRETATION: Navitoclax has a novel mechanism of peripheral thrombocytopenia and T-cell lymphopenia, attributable to high-affinity inhibition of BCL-XL and BCL-2, respectively. On the basis of these findings, a 150 mg 7-day lead-in dose followed by a 325 mg dose administered on a continuous 21/21 dosing schedule was selected for phase 2 study. FUNDING: Abbott Laboratories, Genentech, and National Cancer Institute, National Institutes of Health.