Elisa Cerri

Targeting BCL2 with Venetoclax in Relapsed Chronic Lymphocytic Leukemia

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.).

Venetoclax in relapsed or refractory chronic lymphocytic leukaemia with 17p deletion: a multicentre, open-label, phase 2 study

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.

Venetoclax plus rituximab in relapsed or refractory chronic lymphocytic leukaemia: a phase 1b study.

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.

Novel Functional Germline Variants in the VEGF Receptor 2 Gene and Their Effect on Gene Expression and Microvessel Density in Lung Cancer

Purpose: VEGF receptor 2 (VEGFR-2) plays a crucial role in mediating angiogenic endothelial cell responses via the VEGF pathway, and angiogenesis inhibitors targeting VEGFR-2 are in clinical use. As angiogenesis is a host-driven process, functional heritable variation in KDR, the gene encoding VEGFR-2, may affect VEGFR-2 function and, ultimately, the extent of tumor angiogenesis. Experimental Design: We resequenced KDR using 24 DNAs each from healthy Caucasian, African American, and Asian groups. Nonsynonymous genetic variants were assessed for function by phosphorylation assays. Luciferase reporter gene assays were used to examine effects of variants on gene expression. KDR mRNA and protein expression and microvessel density (MVD) were measured in non–small cell lung cancer (NSCLC) tumor samples, and matching patient DNA samples were genotyped to test for associations with variants of interest. Results: KDR resequencing led to the discovery of 120 genetic variants, of which 25 had not been previously reported. Q472H had increased VEGFR-2 protein phosphorylation and associated with increased MVD in NSCLC tumor samples. −2854C and −2455A increased luciferase expression and associated with higher KDR mRNA levels in NSCLC samples. −271A reduced luciferase expression and associated with lower VEGFR-2 levels in NSCLC samples. −906C and 23408G associated with higher KDR mRNA levels in NSCLC samples. Conclusions: This study has defined KDR genetic variation in 3 populations and identified common variants that impact on tumoral KDR expression and vascularization. These findings may have important implications for understanding the molecular basis of genetic associations between KDR variation and clinical phenotypes related to VEGFR-2 function. Clin Cancer Res; 17(16); 5257–67. ©2011 AACR.

Tumor Lysis Syndrome in Chronic Lymphocytic Leukemia with Novel Targeted Agents

Tumor lysis syndrome is an uncommon but potentially life‐threatening complication associated with the treatment of some cancers. In this review, prevention strategies and management of patients with chronic lymphocytic leukemia who develop tumor lysis syndrome are described.

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.

Abstract 5136: Discovery of novel functional germline variations in the vascular endothelial growth factor receptor 2 gene (KDR) and their effect on gene expression and microvessel density in lung cancer

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Background: VEGFR-2 plays a crucial role in mediating angiogenic endothelial cell responses via the VEGF pathway and VEGFR-2 inhibitors are in clinical use. Angiogenesis is a host-driven process and heritable variation in KDR, the gene encoding VEGFR-2, may impact on angiogenesis. We have previously characterized KDR germline genetic variation by resequencing (Ye et al., AACR, 2007;737). However, very limited data are available on the molecular function of KDR germline variants and their resulting effect on tumoral expression and vascularization. The purpose of this study was to identify functional variants affecting KDR expression and microvessel density (MVD) in lung cancer. Methods: The molecular function of the non-synonymous variants R106W, V297I, Q472H and C482R was assessed by testing their effect on VEGFR-2 phosphorylation (measured via immunoblotting) after VEGFA165 exposure in HEK293 cells. Four 5’ upstream region SNPs were examined by luciferase reporter assay in endothelial SVEC4-10 cells. To validate these results and examine the effects of other KDR SNPs, KDR mRNA and VEGFR-2 protein expression were measured by quantitative PCR and immunohistochemistry in non-small cell lung cancer (NSCLC) samples from Caucasian patients and MVD was assessed by immunohistochemistry (anti-CD31). Patients were genotyped for KDR SNPs and their association with mRNA, protein expression, or MVD was evaluated by linear regression. Results: Among the non-synonymous SNPs, the only significant observation was that Q472H had a 46% increase in VEGFR-2 phosphorylation relative to the wild-type variant after VEGFA165 stimulation (p=0.035); in agreement with this finding, Q472H was associated with 22% greater MVD in 168 NSCLC patients (p=0.05). Of the putatively regulatory SNPs, -2008G and -1942G had no effect on luciferase expression. -2854C and -2455A showed 10-20% higher luciferase expression than the wild-type variant (p<0.05) and they were associated with 23% greater tumor KDR mRNA expression in 66 NSCLC patients (p=0.014), but had no effect on tumor VEFGR-2 expression; -271A reduced luciferase expression by approximately 50% (Ye et al., AACR 2007;737) and correlated with 10% lower tumor VEGFR-2 expression in 162 NSCLC patients (p=0.01); -906C and 23408G were associated with 20-25% higher tumor KDR mRNA levels (p=0.009 and 0.025, respectively), although these variants had no effect on tumor VEGFR-2 expression. Conclusions: This study has identified novel functional variants which correlate with in vitro gene expression or VEGFR-2 phosphorylation and KDR expression or MVD in NSCLC. This information may be critical for understanding the role of heritable KDR variations as contributing factors to prognosis and lung cancer outcome. Acknowledgment: This research was supported by the American Cancer Society. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5136. doi:10.1158/1538-7445.AM2011-5136

Abstract 2176: Vascular endothelial growth factor receptor-2 (VEGFR-2) gene variations in bronchioloalveolar cell carcinoma (BAC)

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Background VEGF receptor-2 (VEGFR-2) is a key receptor in VEGF-mediated angiogenesis. It plays a significant role in tumor growth and development of metastases. A few studies suggested the angiogenic feature of bronchioalveolar cell carcinoma (BAC), a rare subtype of adenocarcinoma. However the biology of VEGFR-2 in BAC has not been clearly characterized, probably due to its rarity. We sought to determine whether differences in VEGFR-2 expression and microvessel density (MVD) in adenocarcinoma with BAC features (AWBF) might be due to heritable genetic variation in the VEGFR-2 gene. Differences in VEGFR-2 expression and MVD between the pure BAC component of tumor and AWBF, and their comparison with adjacent normal tissue, were also investigated. Methods DNA was extracted from 46 formalin-fixed paraffin embedded AWBF tissues. Four single-nucleotide polymorphisms (SNPs) and four in/dels were genotyped in all tumors. Tissue microarrays (TMAs) were constructed with tumor tissue (pure BAC component and AWBF component for each tumor) and paired adjacent normal lung tissue. TMAs were stained with anti-VEGFR-2 and anti-phosphorylated-VEGFR-2 (pVEGFR-2) antibodies (scoring: 0-9). MVD was determined by staining with an antibody against CD105, and 95% of the samples had either diffused high or focal high staining. Results The −271G>A genotype showed a clear gene-dosage effect on pVEGFR-2 expression (GG>GA>AA, p=0.04, linear trend analysis) in AWBF but not in BAC (p>0.1). The −271G>A genotype does not affect the MVD in both BAC and AWBF (linear trend analysis and Kruskal-Wallis, p>0.1). The other SNPs and in/dels did not show any significant association with VEGFR-2, pVEGFR-2, and MVD (p>0.1). VEGFR-2 and pVEGFR-2 expression in tumor (AWBF and pure BAC) was more than 10 times higher the paired normal tissue (p 0.1). For MVD, although the proportion of diffused high staining was higher in BAC (60%) vs. AWBF (47%), this difference is not statistically significant (p>0.1, Fishers exact test). Discussion Our study shows that heritable gene variation of −271G>A in VEGFR-2 might reduce the expression of VEGFR-2 in AWBF. This is consistent with the effect of −271G>A in a luciferase assay (Ye et al., AACR 2007), as well as its effect on VEGFR-2 and pVEGFR-2 staining in breast cancer (Cerri et al., SABCS 2009, abstract #904). Although our data are suggestive of different pattern of angiogenesis between pure BAC and AWBF, our sample size is too small to draw any definitive conclusions. Additional studies are ongoing to replicate these findings that will establish the role of genetic variation as a determinant of VEGFR-2 expression in BAC, and the biology of angiogenesis in this rare tumor. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2176.