Current status of drug development for patients with multiple myeloma: a review of comparison in China and the rest of world.

Multiple myeloma (MM) is a highly heterogeneous malignancy. The treatment of MM has been significantly advanced in recent years. B cell maturation antigen (BCMA)-targeted immunotherapy and chimeric antigen receptor T (CAR-T) cell therapy have been approved for the treatment of relapsed and refractory MM (RRMM), which will be launched in China shortly. The CD38 (cluster of differentiation 38) antibody, daratumumab, improves the clinical outcomes both RRMM and newly diagnosed MM patients. The combination of daratumumab, bortezomib and dexamethasone achieved favorable outcomes as the first-line therapy in China. However, high-risk patients have limited benefits from these advanced therapeutics, and usually relapse early, progressing into aggressive end-stage MM. Therefore, novel therapies are sought to improve the cancer prognosis in these patients. This review furnishes an overview of the recent clinical developments of these novel drugs and compares the drug candidates under development in China to the rest of the world.

Immune microenvironment characteristics in multiple myeloma progression from transcriptome profiling.

Multiple myeloma (MM) is characterized by clonal expansion of malignant plasma cells in the bone marrow (BM). Despite the significant advances in treatment, relapsed and refractory MM has not yet been completely cured due to the immune dysfunction in the tumor microenvironment (TME). In this study, we analyzed the transcriptome data from patients with newly diagnosed (ND) and relapsed/refractory (R/R) MM to characterize differences in the TME and further decipher the mechanism of tumor progression in MM. We observed highly expressed cancer testis antigens and immune suppressive cell infiltration, such as Th2 and M2 cells, are associated with MM progression. Furthermore, the TGF-ß signature contributes to the worse outcome of patients with R/R MM. Moreover, patients with ND MM could be classified into immune-low and immune-high phenotypes. Immune-high patients with higher IFN-g signatures are associated with MHC-II-mediated CD4+ T-cell response through CIITA stimulation. The baseline TME status could potentially inform new therapeutic choices for the ND MM who are ineligible for autologous stem cell transplantation and may help predict the response to CAR-T for patients with R/R MM. Our study demonstrates how integrating tumor transcriptome and clinical information to characterize MM immune microenvironment and elucidate potential mechanisms of tumor progression and immune evasion, which will provide insights into MM treatment selection.

A phase 2 study of venetoclax plus R-CHOP as first-line treatment for patients with diffuse large B-cell lymphoma.

The phase 2 CAVALLI (NCT02055820) study assessed efficacy and safety of venetoclax, a selective B-cell lymphoma-2 (Bcl-2) inhibitor, with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in first-line (1L) diffuse large B-cell lymphoma (DLBCL), including patients demonstrating Bcl-2 protein overexpression by immunohistochemistry (Bcl-2 IHC+). Eligible patients were ≥18 years of age and had previously untreated DLBCL, Eastern Cooperative Oncology Group performance status ≤2, and International Prognostic Index 2 to 5. Venetoclax 800 mg (days 4-10, cycle 1; days 1-10, cycles 2-8) was administered with rituximab (8 cycles) and cyclophosphamide, doxorubicin, vincristine, and prednisone (6-8 cycles) in 21-day cycles. Primary end points were safety, tolerability, and research_plete response (CR) at end of treatment (EOT). Secondary end points were progression-free survival (PFS) and overall survival. Comparative analyses used covariate-adjusted R-CHOP controls from the GOYA/BO21005 study, an appropriate contemporary benchmark for safety and efficacy. Safety and efficacy analyses included 206 patients. CR rate at EOT was 69% in the overall population and was maintained across Bcl-2 IHC+ subgroups. With a median follow-up of 32.2 months, trends were observed for improved investigator-assessed PFS for venetoclax plus R-CHOP in the overall population (hazard ratio [HR], 0.61; 95% confidence interval [CI], 0.43-0.87) and Bcl-2 IHC+ subgroups (HR, 0.55; 95% CI, 0.34-0.89) vs R-CHOP. Despite a higher incidence of grade 3/4 hematologic adverse events (86%), related mortality was not increased (2%). Chemotherapy dose intensity was similar in CAVALLI vs GOYA. The addition of venetoclax to R-CHOP in 1L DLBCL demonstrates increased, but manageable, myelosuppression and the potential of improved efficacy, particularly in high-risk Bcl-2 IHC+ patient subgroups.

BCL2 Expression in First-Line Diffuse Large B-Cell Lymphoma Identifies a Patient Population With Poor Prognosis.

INTRODUCTION: The prognostic value of B-cell lymphoma 2 (BCL2) expression in de novo diffuse large B-cell lymphoma (DLBCL) treated with immunochemotherapy is of interest to define a target patient population for clinical development of BCL2 inhibitors. We aimed to develop a reproducible immunohistochemistry algorithm and assay to determine BCL2 protein expression and assess the prognostic value of BCL2 in newly diagnosed DLBCL cohorts. PATIENTS AND METHODS: The prospectively defined algorithm incorporated BCL2 staining intensity and percentage of BCL2-positive cells. Functionally relevant cutoffs were based on the sensitivity of lymphoma cell lines to venetoclax. This assay was highly reproducible across laboratories. The prognostic impact of BCL2 expression was assessed in DLBCL patients from the phase 3 MAIN (n = 230) and GOYA (n = 366) trials, and a population-based registry (n = 310). RESULTS: Approximately 50% of tumors were BCL2 positive, with a higher frequency in high International Prognostic Index (IPI) and activated B-cell-like DLBCL subgroups. BCL2 expression was associated with poorer progression-free survival in the MAIN study (hazard ratio [HR], 1.66; 95% confidence interval [CI], 0.81-3.40; multivariate Cox regression adjusted for IPI and cell of origin). This trend was confirmed in the GOYA and registry cohorts in adjusted multivariate analyses (GOYA: HR, 1.72; 95% CI, 1.05-2.82; registry: HR, 1.89; 95% CI, 1.29-2.78). Patients with BCL2 immunohistochemistry-positive and IPI-high disease had the poorest prognosis: 3-year progression-free survival rates were 51% (GOYA) and 37% (registry). CONCLUSION: Findings support use of our BCL2 immunohistochemistry scoring system and assay to select patients with BCL2-positive tumors for future studies.

Venetoclax or placebo in combination with bortezomib and dexamethasone in patients with relapsed or refractory multiple myeloma (BELLINI): a randomised, double-blind, multicentre, phase 3 trial.

BACKGROUND: Venetoclax is a highly selective, potent, oral BCL-2 inhibitor, which induces apoptosis in multiple myeloma cells. Venetoclax plus bortezomib and dexamethasone has shown encouraging clinical efficacy with acceptable safety and tolerability in a phase 1 trial. The aim of this study was to evaluate venetoclax plus bortezomib and dexamethasone in patients with relapsed or refractory multiple myeloma. METHODS: In this randomised, double-blind, multicentre, phase 3 trial, patients aged 18 years or older with relapsed or refractory multiple myeloma, an Eastern Cooperative Oncology Group performance status of 2 or less, who had received one to three previous therapies were enrolled from 90 hospitals in 16 countries. Eligible patients were randomly assigned (2:1) centrally using an interactive response technology system and a block size of three to receive venetoclax (800 mg per day orally) or placebo with bortezomib (1·3 mg/m2 subcutaneously or intravenously and dexamethasone (20 mg orally). Treatment was given in 21-day cycles for the first eight cycles and 35-day cycles from the ninth cycle until disease progression, unacceptable toxicity, or patient withdrawal. Randomisation was stratified by previous exposure to a proteasome inhibitor and the number of previous therapies. Sponsors, investigators, study site personnel, and patients were masked to the treatment allocation throughout the study. The primary endpoint was independent review committee-assessed progression-free survival in the intention-to-treat population. Safety analyses were done in patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, NCT02755597. FINDINGS: Between July 19, 2016, and Oct 31, 2017, 291 patients were randomly assigned to receive venetoclax (n=194) or placebo (n=97). With a median follow-up of 18·7 months (IQR 16·6-21·0), median progression-free survival according to independent review committee was 22·4 months (95% CI 15·3-not estimable) with venetoclax versus 11·5 months (9·6-15·0) with placebo (hazard ratio [HR] 0·63 [95% CI 0·44-0·90]; p=0·010). The most common grade 3 or worse treatment-emergent adverse events were neutropenia (35 [18%] of 193 patients in the venetoclax group vs seven [7%] of 96 patients in the placebo group), pneumonia (30 [16%] vs nine [9%]), thrombocytopenia (28 [15%] vs 29 [30%]), anaemia (28 [15%] vs 14 [15%]), and diarrhoea (28 [15%] vs 11 [11%]). Serious treatment-emergent adverse events occurred in 93 (48%) patients in the venetoclax group and 48 (50%) patients in the placebo group, with eight (4%) treatment-emergent fatal infections reported in the venetoclax group and none reported in the placebo group. Three deaths in the venetoclax group (two from pneumonia and one from septic shock) were considered treatment-related; no deaths in the placebo group were treatment-related. INTERPRETATION: The primary endpoint was met with a significant improvement in independent review committee-assessed progression-free survival with venetoclax versus placebo plus bortezomib and dexamethasone. However, increased mortality was seen in the venetoclax group, mostly because of an increased rate of infections, highlighting the importance of appropriate selection of patients for this treatment option. FUNDING: AbbVie and Genentech.

Venetoclax Plus Rituximab in Relapsed Chronic Lymphocytic Leukemia: 4-Year Results and Evaluation of Impact of Genomic Complexity and Gene Mutations From the MURANO Phase III Study.

PURPOSE: In previous analyses of the MURANO study, fixed-duration venetoclax plus rituximab (VenR) resulted in improved progression-free survival (PFS) compared with bendamustine plus rituximab (BR) in patients with relapsed or refractory chronic lymphocytic leukemia (CLL). At the 4-year follow-up, we report long-term outcomes, response to subsequent therapies, and the predictive value of molecular and genetic characteristics. PATIENTS AND METHODS: Patients with CLL were randomly assigned to 2 years of venetoclax (VenR for the first six cycles) or six cycles of BR. PFS, overall survival (OS), peripheral-blood minimal residual disease (MRD) status, genomic complexity (GC), and gene mutations were assessed. RESULTS: Of 389 patients, 194 were assigned to VenR and 195 to BR. Four-year PFS and OS rates were higher with VenR than BR, at 57.3% and 4.6% (hazard ratio [HR], 0.19; 95% CI, 0.14 to 0.25), and 85.3% and 66.8% (HR, 0.41; 95% CI, 0.26 to 0.65), respectively. Undetectable MRD (uMRD) at end of combination therapy (EOCT) was associated with superior PFS compared with low MRD positivity (HR, 0.50) and high MRD positivity (HR, 0.15). Patients in the VenR arm who received ibrutinib as their first therapy after progression (n = 12) had a reported response rate of 100% (10 of 10 evaluable patients); patients subsequently treated with a venetoclax-based regimen (n = 14) had a reported response rate of 55% (six of 11 evaluable patients). With VenR, the uMRD rate at end of treatment (EOT) was lower in patients with GC than in those without GC (P = .042); higher GC was associated with shorter PFS. Higher MRD positivity rates were seen with BIRC3 and BRAF mutations at EOCT and with TP53, NOTCH1, XPO1, and BRAF mutations at EOT. CONCLUSION: Efficacy benefits with fixed-duration VenR are sustained and particularly durable in patients who achieve uMRD. Salvage therapy with ibrutinib after VenR achieved high response rates. Genetic mutations and GC affected MRD rates and PFS.

Venetoclax-rituximab with or without bendamustine vs bendamustine-rituximab in relapsed/refractory follicular lymphoma.

This open-label phase 2 study (CONTRALTO) assessed the safety and efficacy of BCL-2 inhibitor venetoclax (VEN) plus rituximab (R), and VEN plus bendamustine (B) and R, vs B + R (BR) alone in relapsed/refractory (R/R) follicular lymphoma. Patients in the chemotherapy-free arm (arm A: VEN + R) received VEN 800 mg/d plus R 375 mg/m2 on days 1, 8, 15, and 22 of cycle 1 and day 1 of cycles 4, 6, 8, 10, and 12. After a safety run-in with VEN 600 mg, patients in the chemotherapy-containing cohort were randomized to either VEN + BR (arm B; VEN 800 mg/d for 1 year + 6 cycles of BR [B 90 mg/m2 on days 1 and 2 and R 375 mg/m2 on day 1]) or 6 cycles of BR (arm C). Overall, 163 patients were analyzed (9 in the safety run-in and 52, 51, and 51 in arms A, B, and C, respectively). Complete metabolic/complete response rates were 17% (arm A), 75% (arm B), and 69% (arm C). Of patients in arm B, only 61% received ≥90% of the planned B dose vs 96% of patients in arm C. More frequent hematologic toxicity resulted in more reduced dosing/treatment discontinuation in arm B vs arm C. Rates of grade 3/4 adverse events were 51.9%, 93.9%, and 60.0% in arms A, B, and C, respectively. VEN + BR led to increased toxicity and lower dose intensity of BR than in arm C, but efficacy was similar. Optimizing dose and schedule to maintain BR dose intensity may improve efficacy and tolerability of VEN + BR, while VEN + R data warrant further study. This study was registered at www.clinicaltrials.gov as #NCT02187861.

Genomic Analysis of Circulating Tumor Cells at the Single-Cell Level.

Circulating tumor cells (CTCs) have a great potential for noninvasive diagnosis and real-time monitoring of cancer. A comprehensive evaluation of four whole genome amplification (WGA)/next-generation sequencing workflows for genomic analysis of single CTCs, including PCR-based (GenomePlex and Ampli1), multiple displacement amplification (Repli-g), and hybrid PCR- and multiple displacement amplification-based [multiple annealing and loop-based amplification cycling (MALBAC)] is reported herein. To demonstrate clinical utilities, copy number variations (CNVs) in single CTCs isolated from four patients with squamous non-small-cell lung cancer were profiled. Results indicate that MALBAC and Repli-g WGA have significantly broader genomic coverage compared with GenomePlex and Ampli1. Furthermore, MALBAC coupled with low-pass whole genome sequencing has better coverage breadth, uniformity, and reproducibility and is superior to Repli-g for genome-wide CNV profiling and detecting focal oncogenic amplifications. For mutation analysis, none of the WGA methods were found to achieve sufficient sensitivity and specificity by whole exome sequencing. Finally, profiling of single CTCs from patients with non-small-cell lung cancer revealed potentially clinically relevant CNVs. In conclusion, MALBAC WGA coupled with low-pass whole genome sequencing is a robust workflow for genome-wide CNV profiling at single-cell level and has great potential to be applied in clinical investigations. Nevertheless, data suggest that none of the evaluated single-cell sequencing workflows can reach sufficient sensitivity or specificity for mutation detection required for clinical applications.

Integration of cell of origin into the clinical CNS International Prognostic Index improves CNS relapse prediction in DLBCL.

Central nervous system (CNS) relapse carries a poor prognosis in diffuse large B-cell lymphoma (DLBCL). Integrating biomarkers into the CNS-International Prognostic Index (CNS-IPI) risk model may improve identification of patients at high risk for developing secondary CNS disease. CNS relapse was analyzed in 1418 DLBCL patients treated with obinutuzumab or rituximab plus cyclophosphamide, doxorubicin, vincristine, prednisone chemotherapy in the phase 3 GOYA study. Cell of origin (COO) was assessed using gene-expression profiling. BCL2 and MYC protein expression was analyzed by immunohistochemistry. The impact of CNS-IPI, COO, and BCL2/MYC dual-expression status on CNS relapse was assessed using a multivariate Cox regression model (data available in n = 1418, n = 933, and n = 688, respectively). High CNS-IPI score (hazard ratio [HR], 4.0; 95% confidence interval [CI], 1.3-12.3; P = .02) and activated B-cell‒like (ABC) (HR, 5.2; 95% CI, 2.1-12.9; P = .0004) or unclassified COO subtypes (HR, 4.2; 95% CI, 1.5-11.7; P = .006) were independently associated with CNS relapse. BCL2/MYC dual-expression status did not impact CNS relapse risk. Three risk subgroups were identified based on the presence of high CNS-IPI score and/or ABC/unclassified COO (CNS-IPI-C model): low risk (no risk factors, n = 450 [48.2%]), intermediate risk (1 factor, n = 408 [43.7%]), and high risk (both factors, n = 75 [8.0%]). Two-year CNS relapse rates were 0.5%, 4.4%, and 15.2% in the respective risk subgroups. Combining high CNS-IPI and ABC/unclassified COO improved CNS relapse prediction and identified a patient subgroup at high risk for developing CNS relapse. The study was registered at www.clinicaltrials.gov as #NCT01287741.

Fixed Duration of Venetoclax-Rituximab in Relapsed/Refractory Chronic Lymphocytic Leukemia Eradicates Minimal Residual Disease and Prolongs Survival: Post-Treatment Follow-Up of the MURANO Phase III Study.

PURPOSE: The MURANO study demonstrated significant progression-free survival (PFS) benefit for fixed-duration venetoclax-rituximab compared with bendamustine-rituximab in relapsed/refractory chronic lymphocytic leukemia. With all patients off treatment, we report minimal residual disease (MRD) kinetics and updated outcomes. METHODS: Patients were randomly assigned to 2 years of venetoclax plus rituximab during the first six cycles, or six cycles of bendamustine-rituximab. Primary end point was PFS. Safety and peripheral blood (PB) MRD status-at cycle 4, 2 to 3 months after end of combination therapy (EOCT), and every 3 to 6 months thereafter-were secondary end points. RESULTS: Of 194 patients, 174 (90%) completed the venetoclax-rituximab phase and 130 (67%) completed 2 years of venetoclax. With a median follow-up of 36 months, PFS and overall survival remain superior to bendamustine-rituximab (hazard ratio, 0.16 [95% CI, 0.12 to 0.23]; and hazard ratio, 0.50 [95% CI, 0.30 to 0.85], respectively). Patients who received venetoclax-rituximab achieved a higher rate of PB undetectable MRD (uMRD; less than 10-4) at EOCT (62% v 13%) with superiority sustained through month 24 (end of therapy). Overall, uMRD status at EOCT predicted longer PFS. Among those with detectable MRD, low-level MRD (10-4 to less than 10-2) predicted improved PFS compared with high-level MRD (10-2 or greater). At a median of 9.9 months (range, 1.4 to 22.5 months) after completing fixed-duration venetoclax-rituximab, overall only 12% (16 of 130) of patients developed disease progression (11 high-level MRD, three low-level MRD). At the end of therapy, 70% and 98% of patients with uMRD remained in uMRD and without disease progression, respectively. CONCLUSION: With all patients having finished treatment, continued benefit was observed for venetoclax-rituximab compared with bendamustine-rituximab. uMRD rates were durable and predicted longer PFS, which establishes the impact of PB MRD on the benefit of fixed-duration, venetoclax-containing treatment. Low conversion to detectable MRD and sustained PFS after completion of 2 years of venetoclax-rituximab demonstrate the feasibility of this regimen.

Immune Characteristics of Chinese Diffuse Large B-Cell Lymphoma Patients: Implications for Cancer Immunotherapies.

Immunotherapeutic agents have demonstrated encouraging signs of clinical utility in non-Hodgkin lymphoma. The goal of this study is to analyze the immune characteristics of Chinese patients with diffuse large B-cell lymphoma (DLBCL) to inform the development of immunotherapies in this patient population. Tumor samples from 211 DLBCL patients were analyzed for cell of origin (COO) and immune characteristics using the NanoString platform as well as MYC protein expression through immunohistochemistry. Lower incidence of the germinal center B-cell (GCB) subtype (93/211, 44.1%) was observed in this cohort. Compared to the GCB subtype, the activated B-cell (ABC) subtype was associated with significantly increased expression of multiple pro-inflammatory gene signatures and decreased expression of anti-inflammatory gene signatures. Instead of affecting the pro-inflammatory genes, MYC protein overexpression showed a negative correlation with the expression of T-cell receptor (TCR) and T regulatory genes as well as the OX40 gene. Regardless of COO, higher PD-L1 or IDO1 gene expression correlated with increased expression of T effector and Interferon-γ gene signatures while the expression of multiple oncogenes including ACTR3B, ERBB2, AKT2 and SMARCD1 was down-regulated. Our findings may thus be helpful in guiding further development of immunotherapies for the different subsets of Chinese DLBCL patients.

Venetoclax-Rituximab in Relapsed or Refractory Chronic Lymphocytic Leukemia.

BACKGROUND: Venetoclax inhibits BCL2, an antiapoptotic protein that is pathologically overexpressed and that is central to the survival of chronic lymphocytic leukemia cells. We evaluated the efficacy of venetoclax in combination with rituximab in patients with relapsed or refractory chronic lymphocytic leukemia. METHODS: In this randomized, open-label, phase 3 trial, we randomly assigned 389 patients to receive venetoclax for up to 2 years (from day 1 of cycle 1) plus rituximab for the first 6 months (venetoclax-rituximab group) or bendamustine plus rituximab for 6 months (bendamustine-rituximab group). The trial design did not include crossover to venetoclax plus rituximab for patients in the bendamustine-rituximab group in whom progression occurred. The primary end point was investigator-assessed progression-free survival. RESULTS: After a median follow-up period of 23.8 months, the rate of investigator-assessed progression-free survival was significantly higher in the venetoclax-rituximab group (32 events of progression or death in 194 patients) than in the bendamustine-rituximab group (114 events in 195 patients); the 2-year rates of progression-free survival were 84.9% and 36.3%, respectively (hazard ratio for progression or death, 0.17; 95% confidence interval [CI], 0.11 to 0.25; P<0.001 by the stratified log-rank test). The benefit was maintained across all clinical and biologic subgroups, including the subgroup of patients with chromosome 17p deletion; the 2-year rate of progression-free survival among patients with chromosome 17p deletion was 81.5% in the venetoclax-rituximab group versus 27.8% in the bendamustine-rituximab group (hazard ratio, 0.13; 95% CI, 0.05 to 0.29), and the 2-year rate among those without chromosome 17p deletion was 85.9% versus 41.0% (hazard ratio, 0.19; 95% CI, 0.12 to 0.32). The benefit of venetoclax plus rituximab over bendamustine plus rituximab was confirmed by an independent review committee assessment of progression-free survival and other secondary efficacy end points. The rate of grade 3 or 4 neutropenia was higher in the venetoclax-rituximab group than in the bendamustine-rituximab group, but the rates of grade 3 or 4 febrile neutropenia and infections or infestations were lower with venetoclax than with bendamustine. The rate of grade 3 or 4 tumor lysis syndrome in the venetoclax-rituximab group was 3.1% (6 of 194 patients). CONCLUSIONS: Among patients with relapsed or refractory chronic lymphocytic leukemia, venetoclax plus rituximab resulted in significantly higher rates of progression-free survival than bendamustine plus rituximab. (Funded by Genentech and AbbVie; ClinicalTrials.gov number, NCT02005471 .).

Efficacy of venetoclax as targeted therapy for relapsed/refractory t(11;14) multiple myeloma.

Venetoclax is a selective, orally bioavailable BCL-2 inhibitor that induces cell death in multiple myeloma (MM) cells, particularly in those harboring t(11;14), which express high levels of BCL-2 relative to BCL-XL and MCL-1. In this phase 1 study, patients with relapsed/refractory MM received venetoclax monotherapy. After a 2-week lead-in with weekly dose escalation, daily venetoclax was given at 300, 600, 900, or 1200 mg in dose-escalation cohorts and 1200 mg in the safety expansion. Dexamethasone could be added on progression during treatment. Sixty-six patients were enrolled (30, dose-escalation cohorts; 36, safety expansion). Patients received a median of 5 prior therapies (range, 1-15); 61% were bortezomib and lenalidomide double refractory, and 46% had t(11;14). Venetoclax was generally well tolerated. Most common adverse events included mild gastrointestinal symptoms (nausea [47%], diarrhea [36%], vomiting [21%]). Cytopenias were the most common grade 3/4 events, with thrombocytopenia (32%), neutropenia (27%), anemia (23%), and leukopenia (23%) reported. The overall response rate (ORR) was 21% (14/66), and 15% achieved very good partial response or better (≥VGPR). Most responses (12/14 [86%]) were reported in patients with t(11;14). In this group, ORR was 40%, with 27% of patients achieving ≥VGPR. Biomarker analysis confirmed that response to venetoclax correlated with higher BCL2:BCL2L1 and BCL2:MCL1 mRNA expression ratios. Venetoclax monotherapy at a daily dose up to 1200 mg has an acceptable safety profile and evidence of single-agent antimyeloma activity in patients with relapsed/refractory MM, predominantly in patients with t(11;14) abnormality and those with a favorable BCL2 family profile. Registered at www.clinicaltrials.gov: #NCT01794520.

Promising efficacy and acceptable safety of venetoclax plus bortezomib and dexamethasone in relapsed/refractory MM.

The antiapoptotic proteins BCL-2 and myeloid cell leukemia sequence 1 (MCL-1) promote multiple myeloma (MM) cell survival. Venetoclax is a selective, orally bioavailable small-molecule BCL-2 inhibitor; bortezomib can indirectly inhibit MCL-1. In preclinical studies, venetoclax enhanced bortezomib activity, suggesting that cotargeting of BCL-2 and MCL-1 could be an effective treatment strategy in myeloma. This phase 1b trial studied patients with relapsed/refractory MM receiving daily venetoclax (50-1200 mg per designated dose cohort; 800 mg in safety expansion) in combination with bortezomib and dexamethasone. A total of 66 patients were enrolled (54 in the dose-escalation cohorts and 12 in the safety expansion). Patients had received a median of 3 prior therapies (range, 1-13); 26 (39%) were refractory to prior bortezomib and 35 (53%) to lenalidomide; 39 (59%) had prior stem cell transplant. The combination was generally well tolerated, and common adverse events included mild gastrointestinal toxicities (diarrhea [46%], constipation [41%], and nausea [38%]) and grade 3/4 cytopenias (thrombocytopenia [29%] and anemia [15%]). The overall response rate (ORR) was 67% (44/66); 42% achieved very good partial response or better (≥VGPR). Median time to progression and duration of response were 9.5 and 9.7 months, respectively. ORR of 97% and ≥VGPR 73% were seen in patients not refractory to bortezomib who had 1 to 3 prior therapies. Patients with high BCL2 expression had a higher ORR (94% [17/18]) than patients with low BCL2 expression (59% [16/27]). This novel combination of venetoclax with bortezomib and dexamethasone has an acceptable safety profile and promising efficacy in patients with relapsed/refractory MM. This trial was registered at www.clinicaltrials.gov as #NCT01794507.

Rituximab treatment circumvents the prognostic impact of tumor-infiltrating T-cells in follicular lymphoma patients.

Previous immunohistochemical (IHC) studies showed controversial data about the prognostic value of tumor-infiltrating lymphocytes (TILs) in follicular lymphoma (FL). To clarify this issue, a large series of FL samples from rituximab-treated patients enrolled in the randomized PRIMA trial was examined. IHC was quantified using automated image analysis in 417, 287, 418, 406, 379, and 369 patients for CD3, CD4, CD8, PD1, ICOS, and FOXP3, respectively. RNAseq analysis was used to quantify TIL-related mRNA transcripts from 148 patients. When each IHC marker was used as a continuous variable in the whole cohort, high CD3 counts were associated with better progression-free survival (PFS) (P = .025). When an optimal IHC cut point was applied to the whole patient population, high CD3 counts and high PD1 counts were associated with better PFS (P = .011 and P = .044, respectively), whereas none of the other TIL markers had any significant correlation with outcome. When a stringent analysis was performed by dividing the whole cohort into a training set and a validation set, none of the TIL markers showed a prognostic significance in both groups. RNAseq analysis showed a significant correlation between high levels of CD3 and CD8 transcripts and better PFS (P = .001 and P = .037, respectively). No prognostic correlation was found as to the level of other immune gene transcripts. These results suggest that the IHC prognostic value of TILs is circumvented by rituximab treatment, although there is a trend for high numbers of CD3+ TILs to correlate with better PFS.

BCL2 mutations do not confer adverse prognosis in follicular lymphoma patients treated with rituximab.

BCL2 mutations have been suggested to confer an adverse prognosis to follicular lymphoma (FL) patients, but their prognostic value has not been assessed in patients treated with a rituximab-containing regimen. Here we evaluated the prognostic value of BCL2 mutations in a large prospective cohort of 252 patients with FL treated with immunochemotherapy in the PRIMA randomized trial. Using a DNA-targeted sequencing approach, we detected amino acid altering mutations in 135 patients (54%) and showed that these mutations were probably mediated by the over-activation of AICDA (activation-induced cytidine deaminase) in the context of the t(14;18) translocation. The BCL2 variants identified in PRIMA patients affected the BH1, BH2, and BH3 functional motifs at a lower frequency than the N-terminus and flexible loop domain, with mostly conservative aminoacid changes. With a median follow-up of 6.7 years, we did not observe any impact of BCL2 mutations either on overall survival or progression-free survival.

Expression of MET in circulating tumor cells correlates with expression in tumor tissue from advanced-stage lung cancer patients.

Given the difficulty in obtaining adequate tissue in NSCLC, we investigated the utility of circulating tumor cells (CTCs) for MET status assessment in NSCLC patients. We used two platforms for CTC capture, and assessed MET expression in CTCs and matched-bronchial biopsies in patients with advanced-stage III/IV lung adenocarcinoma. Baseline peripheral blood was collected from 256 advanced-stage III/IV NSCLC patients from Genentech clinical trials, and from 106 patients with advanced-stage III/IV lung adenocarcinoma treated at the Department of Pneumology, Pasteur Hospital, Nice. CTCs were enriched using CellSearch (Genentech), or ISET technologies (Pasteur Hospital). MET expression was evaluated by immunofluorescence on CellSearch, and by immunocytochemistry on ISET-enriched CTCs and on matched FFPE tissue sections (Pasteur Hospital). CTCs were detected in 83 of 256 (32%) patients evaluated on CellSearch, with 30 samples (12%) exhibiting ≥ 5 CTCs/7.5 ml blood. On ISET, CTC were observed in 80 of 106 patients (75%), and 79 patients (75%) exhibited ≥ 5 CTCs/4 ml blood. MET expression on ISET CTCs was positive in 72% of cases, and the MET expression on matched-patient tissue was positive in 65% patients using the Onartuzumab IHC scoring algorithm (93% concordance). Quantification of MET expression using H-scores showed strong correlation between MET expression in tissue and CTCs (Spearman correlation, 0.93). MET status in CTCs isolated on ISET filters from blood samples of advanced-stage NSCLC patients correlated strongly with MET status in tumor tissue, illustrating the potential for using CTCs as a non-invasive, real-time biopsy to determine MET status of patients entering clinical trials.

Mutation load and an effector T-cell gene signature may distinguish immunologically distinct and clinically relevant lymphoma subsets.

Identifying follicular lymphoma (FL) patients with preexisting antitumor immunity will inform precision medicine strategies for novel cancer immunotherapies. Using clinical and genomic data from 249 FL patients, we determined the clinical impact of mutation load and an effector T-cell (Teff) gene signature as proxies for the likelihood of a functional immune response. The FL mutation load estimate varied between 0 and 33 mutations per Mb (median, 6.6), and 92% of FL patients with a high mutation load had high Teff gene expression (P = .001). The mutation load was associated with a benefit from rituximab maintenance: FL patients with low mutation loads experienced a profound benefit from rituximab maintenance (hazard ratio [HR], 0.29; 95% confidence interval [CI], 0.15-0.54; P < .001). The Teff gene signature was prognostic as a continuous predictor (P = .008), and was used to separate FL patients into 2 groups, an "inflamed" subset (Teff-high; n = 74) and an "uninflamed" subset (Teff-low; n = 75), with longer progression-free survival (PFS) in the inflamed FL subset (PFS HR, 0.39; 95% CI, 0.21-0.70; P = .002). Furthermore, the subset of inflamed FL tumors demonstrated high expression of other T-cell signatures and counterregulatory genes, which also correlate with PFS. Mutation load and Teff gene expression may help identify immunologically distinct lymphoma subsets relevant for modern immunotherapies.

Expression Profile of BCL-2, BCL-XL, and MCL-1 Predicts Pharmacological Response to the BCL-2 Selective Antagonist Venetoclax in Multiple Myeloma Models.

BCL-2 family proteins dictate survival of human multiple myeloma cells, making them attractive drug targets. Indeed, multiple myeloma cells are sensitive to antagonists that selectively target prosurvival proteins such as BCL-2/BCL-XL (ABT-737 and ABT-263/navitoclax) or BCL-2 only (ABT-199/GDC-0199/venetoclax). Resistance to these three drugs is mediated by expression of MCL-1. However, given the selectivity profile of venetoclax it is unclear whether coexpression of BCL-XL also affects antitumor responses to venetoclax in multiple myeloma. In multiple myeloma cell lines (n = 21), BCL-2 is expressed but sensitivity to venetoclax correlated with high BCL-2 and low BCL-XL or MCL-1 expression. Multiple myeloma cells that coexpress BCL-2 and BCL-XL were resistant to venetoclax but sensitive to a BCL-XL-selective inhibitor (A-1155463). Multiple myeloma xenograft models that coexpressed BCL-XL or MCL-1 with BCL-2 were also resistant to venetoclax. Resistance to venetoclax was mitigated by cotreatment with bortezomib in xenografts that coexpressed BCL-2 and MCL-1 due to upregulation of NOXA, a proapoptotic factor that neutralizes MCL-1. In contrast, xenografts that expressed BCL-XL, MCL-1, and BCL-2 were more sensitive to the combination of bortezomib with a BCL-XL selective inhibitor (A-1331852) but not with venetoclax cotreatment when compared with monotherapies. IHC of multiple myeloma patient bone marrow biopsies and aspirates (n = 95) revealed high levels of BCL-2 and BCL-XL in 62% and 43% of evaluable samples, respectively, while 34% were characterized as BCL-2(High)/BCL-XL (Low) In addition to MCL-1, our data suggest that BCL-XL may also be a potential resistance factor to venetoclax monotherapy and in combination with bortezomib. Mol Cancer Ther; 15(5); 1132-44. ©2016 AACR.