piperidines and fludarabine

Advances in the molecular biology of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and development of molecularly targeted therapies have resulted in treatment innovations. Therapeutic approaches for previously untreated CLL/SLL patients are changing from chemoimmunotherapy (CIT) to molecularly targeted drugs. The aim of therapy for CLL patients has been to control the disease; however, FCR (fludarabine, cyclophosphamide, rituximab) has improved outcomes and reduced the high incidence of undetectable minimum/measurable residual disease (MRD) in previously untreated CLL patients with no 17p deletion/TP53 disruption and mutated immunoglobulin heavy chain gene (IGHV). Patients achieving undetectable MRD in the bone marrow are expected to be cured. BTK inhibitors and BCL-2 inhibitors are effective for CLL/SLL patients. However, atrial fibrillation and bleeding are associated with the BTK inhibitor, ibrutinib, while tumor lysis syndrome is an adverse event (AE) of the BCL-2 inhibitor, venetoclax. Although these novel targeted drugs are very useful, they are also expensive. Emergence of resistant clones of CLL cells must also be addressed. Therefore, treatments of indefinite duration until progression have been replaced by fixed-duration treatments. This review introduces advances in the treatment of previously untreated CLL/SLL patients in Europe and the United States.

Topics: Adenine; Antineoplastic Combined Chemotherapy Protocols; Atrial Fibrillation; Bridged Bicyclo Compounds, Heterocyclic; Cyclophosphamide; Humans; Immunotherapy; Japan; Leukemia, Lymphocytic, Chronic, B-Cell; Molecular Targeted Therapy; Neoplasm, Residual; Piperidines; Pyrazoles; Pyrimidines; Rituximab; Sulfonamides; Vidarabine

A systematic literature review and network meta-analysis were conducted to determine the relative efficacy and safety of interventions for treatment-naive chronic lymphocytic leukemia patients, as comparative evidence is scarce.. Relative treatment effects of progression-free survival, overall survival and safety outcomes were estimated via network meta-analysis based on data identified via systematic literature review.. Ibrutinib was superior in all pairwise comparisons for progression-free survival (probability to be better [P] range: overall population: 69-100%; fludarabine-ineligible population: 69-100%) and overall survival (P range: overall: 89-100%; fludarabine-ineligible: 91-100%) and had the highest probability of being best for all outcomes.. Ibrutinib provides superior benefit in survival and safety compared with other front-line treatments of chronic lymphocytic leukemia.

Topics: Adenine; Antineoplastic Combined Chemotherapy Protocols; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Network Meta-Analysis; Piperidines; Progression-Free Survival; Pyrazoles; Pyrimidines; Vidarabine

The treatment landscape of chronic lymphocytic leukemia (CLL) has changed dramatically in the last few years. The role of chemoimmunotherapy has declined significantly for patients with CLL. Fludarabine, cyclophosphamide, rituximab chemotherapy remains the standard frontline therapy for young fit patients with CLL, especially if

Topics: Adenine; Age Factors; Antineoplastic Combined Chemotherapy Protocols; Chlorambucil; Chromosome Deletion; Chromosomes, Human, Pair 17; Clinical Trials, Phase III as Topic; Cyclophosphamide; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Piperidines; Pyrazoles; Pyrimidines; Rituximab; Smith-Magenis Syndrome; Vidarabine

During the past 5 years, rapid therapeutic advances have changed the landscape of chronic lymphocytic leukemia (CLL) therapy. This disease has traditionally been treated using cytotoxic chemotherapy regimens in combination with anti-CD20 antibody treatment, and recent long-term follow-up data from multiple centers suggest that fit patients with CLL with favorable disease features-particularly mutated immunoglobulin heavy chain variable region (IGHV) genes-derive very long-term benefit from the most potent of these regimens, namely the fludarabine, cyclophosphamide, and rituximab (FCR) regimen. The advent of oral targeted therapies, particularly ibrutinib and idelalisib, has provided generally well-tolerated and highly effective additional options that have come into widespread use in the relapsed setting. Additional agents are advancing in clinical development, with the BCL-2 inhibitor venetoclax likely to be approved by the U.S. Food and Drug Administration (FDA) in 2016. With the development of these novel therapies for patients with relapsed CLL, many unanswered questions remain, including the optimal sequence (first vs. second line), duration, discontinuation, and combination of these agents. In addition, recent publications show the emergence of a pattern of treatment resistance in certain subgroups of patients with del(17p) and complex karyotype that needs further study and improvement. Because the field of CLL management has become much more complex, we focus here on understanding the recent data and discuss many of the questions and controversies important for how we approach patients with CLL.

Topics: Adenine; Antibodies, Monoclonal; Antineoplastic Combined Chemotherapy Protocols; Bridged Bicyclo Compounds, Heterocyclic; Cyclophosphamide; Humans; Immunotherapy; Leukemia, Lymphocytic, Chronic, B-Cell; Molecular Targeted Therapy; Piperidines; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-bcl-2; Purines; Pyrazoles; Pyrimidines; Quinazolinones; Rituximab; Sulfonamides; Vidarabine

Despite important advances in the treatment of first-line chronic lymphocytic leukemia (CLL) over the past decade, CLL remains an incurable disease with significant unmet needs. The combination of rituximab with fludarabine and cyclophosphamide (FCR) significantly improved overall survival and progression-free survival compared with fludarabine and cyclophosphamide alone in first-line treatment of CLL. However, because of its high toxicity, FCR is only recommended for younger, fit patients who can tolerate the treatment. This excludes a large fraction of CLL patients who are elderly and/or who have comorbidities. Thus, determining the appropriate treatment choices for this group of patients who are unfit for FCR treatment is a significant challenge in CLL. Current treatment choices in Canadian practice include bendamustine with rituximab, fludarabine with rituximab, and chlorambucil with rituximab. Two novel monoclonal antibodies, ofatumumab and obinutuzumab, have also recently received Health Canada approval for the first-line treatment of CLL patients in combination with chlorambucil. In addition, the Bruton tyrosine kinase inhibitor, ibrutinib, has recently been approved by Health Canada for the first-line treatment of CLL patients with deletion 17p. In the coming years, several other novel agents that are being developed are likely to change the CLL treatment landscape dramatically, however, because these novel agents are currently unavailable, the purpose of this review is to recommend the best treatment approaches in Canada using currently available therapies.

Topics: Adenine; Alemtuzumab; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bendamustine Hydrochloride; Canada; Chlorambucil; Cyclophosphamide; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Piperidines; Pyrazoles; Pyrimidines; Rituximab; Vidarabine

Topics: Adenine; Alemtuzumab; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Combined Chemotherapy Protocols; Bendamustine Hydrochloride; Cyclophosphamide; Doxorubicin; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Nitrogen Mustard Compounds; Piperidines; Practice Guidelines as Topic; Prednisone; Pyrazoles; Pyrimidines; Rituximab; Vidarabine; Vincristine

The last several years have seen an explosion of novel therapies for chronic lymphocytic leukemia (CLL). These include the antibody obintutuzumab (GA-101), as well as small-molecule inhibitors of key pathways involved in the pathogenesis of CLL, specifically the B-cell receptor (BCR) pathway (especially Bruton's tyrosine kinase [BTK] and P13K), and the antiapoptotic pathway (especially BCL-2). We will consider each in turn, focusing on the molecules most advanced in clinical development. There has also been extensive development in rewiring the patient's own immune system to treat CLL. This has been done through modifying autologous T cells to express a chimeric antigen receptor (CAR). Thus far all CAR-T preparations have targeted the CD19 antigen. This is a good rational for B-cell malignancies as CD19 expression is limited to B-cell malignancies and normal B cells. The in vivo amplification of the transduced T cells relies on signaling and co-signaling domains and provides significant killing of CLL cells. As exciting as these novel agents and approaches are, they obviously beg the question, will chemotherapy as a treatment for CLL soon be obsolete? Although chemotherapy is associated with known short-term toxicities, it has the advantage of being completed in a short period of time and being relatively inexpensive in comparison to novel therapies. In addition, long-term follow-up of results with chemoimmunotherapy have now identified a group of patients whose remissions are maintained for more than 10 years. An important question that will arise going forward is how to incorporate novel agents without eliminating the long term benefits possible with chemoimmunotherapy in a subset of patients with CLL.

Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Antibodies, Monoclonal, Humanized; Antigens, CD19; Antineoplastic Combined Chemotherapy Protocols; Bridged Bicyclo Compounds, Heterocyclic; Cyclophosphamide; Humans; Immunotherapy; Isoquinolines; Leukemia, Lymphocytic, Chronic, B-Cell; Molecular Targeted Therapy; Piperidines; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-bcl-2; Purines; Pyrazoles; Pyrimidines; Quinazolinones; Rituximab; Small Molecule Libraries; Sulfonamides; Vidarabine

Chemoimmunotherapy has been the standard of care for chronic lymphocytic leukemia (CLL). However, the introduction of B-cell receptor (BCR) kinase inhibitors such as ibrutinib has the potential to eliminate the role of chemotherapy in the treatment of CLL. How to best incorporate old and new therapies for CLL in this landscape is increasingly complex.. This article reviews current data available to clinicians and integrates these data to provide a strategy that can be used to approach the treatment of CLL in the era of BCR signaling inhibitors.. Current strategies separate patients based on age or functional status as well as genetics [presence or absence of del(17)(p13.1)]. In the era of targeted therapy, this will likely continue based on current available data. Phase III studies support chemoimmunotherapy as the initial standard therapy for patients without del(17)(p13.1). Choice of chemotherapy (fludarabine plus cyclophosphamide, bendamustine, or chlorambucil) and anti-CD20 antibody (rituximab, ofatumumab, or obinutuzumab) varies based on regimen and patient status. For patients with del(17)(p13.1), no standard initial therapy exists, although several options supported by phase II clinical trials (methylprednisolone plus alemtuzumab or ibrutinib) seem better than chemoimmunotherapy. Treatment of relapsed CLL seems to be best supported by ibrutinib-based therapy. Completion of trials with ibrutinib and other new agents in the near future will offer opportunity for chemotherapy-free treatment across all groups of CLL.. Therapy for CLL has evolved significantly over the past decade with introduction of targeted therapy for CLL. This has the potential to completely transform how CLL is treated in the future.

Topics: Adenine; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Bendamustine Hydrochloride; Chlorambucil; Cyclophosphamide; Drug Resistance, Neoplasm; Gene Deletion; Hematopoietic Stem Cell Transplantation; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Molecular Targeted Therapy; Nitrogen Mustard Compounds; Piperidines; Practice Patterns, Physicians'; Purines; Pyrazoles; Pyrimidines; Quinazolinones; Vidarabine

Chemoimmunotherapy with combined fludarabine, cyclophosphamide and rituximab (FCR) has been an effective treatment for patients with chronic lymphocytic leukemia (CLL). We initiated a phase II trial for previously untreated patients with CLL with mutated IGHV and absence of del(17p)/TP53 mutation. Patients received ibrutinib, fludarabine, cyclophosphamide, and obinutuzumab (iFCG) for three cycles. Patients who achieved complete remission (CR)/CR with incomplete count recvoery (CRi) with marrow undetectable measurable residual disease (U-MRD) received additional nine cycles of ibrutinib with three cycles of obinutuzumab; all others received nine additional cycles of ibrutinib and obinutuzumab. Patients in marrow U-MRD remission after cycle 12 discontinued all treatment, including ibrutinib. Forty-five patients were treated. The median follow-up is 41.3 months. Among the total 45 treated patients, after three cycles, 38% achieved CR/CRi and 87% achieved marrow U-MRD. After cycle 12, the corresponding numbers were 67% and 91%, respectively. Overall, 44/45 (98%) patients achieved marrow U-MRD as best response. No patient had CLL progression. The 3-year progression-free survival (PFS) and overall survival (OS) were 98% and 98%, respectively. Per trial design, all patients who completed cycle 12 discontinued ibrutinib, providing for a time-limited therapy. Grade 3-4 neutropenia and thrombocytopenia occurred in 58% and 40% patients, respectively. The iFCG regimen with only 3 cycles of chemotherapy is an effective, time-limited regimen for patients with CLL with mutated IGHV and without del(17p)/TP53 mutation.

Topics: Adenine; Adult; Aged; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Cyclophosphamide; Female; Follow-Up Studies; Humans; Immunoglobulin Heavy Chains; Immunoglobulin Variable Region; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Mutation; Piperidines; Prognosis; Survival Rate; Tumor Suppressor Protein p53; Vidarabine

E1912 was a randomized phase 3 trial comparing indefinite ibrutinib plus 6 cycles of rituximab (IR) to 6 cycles of fludarabine, cyclophosphamide, and rituximab (FCR) in untreated younger patients with CLL. We describe measurable residual disease (MRD) levels in E1912 over time and correlate them with clinical outcome. Undetectable MRD rates (<1 CLL cell per 104 leukocytes) were 29.1%, 30.3%, 23.4%, and 8.6% at 3, 12, 24, and 36 months for FCR, and significantly lower at 7.9%, 4.2%, and 3.7% at 12, 24, and 36 months for IR, respectively. Undetectable MRD at 3, 12, 24, and 36 months was associated with longer progression-free survival (PFS) in the FCR arm, with hazard ratios (MRD detectable/MRD undetectable) of 4.29 (95% confidence interval [CI], 1.89-9.71), 3.91 (95% CI, 1.39-11.03), 14.12 (95% CI, 1.78-111.73), and not estimable (no events among those with undetectable MRD), respectively. In the IR arm, patients with detectable MRD did not have significantly worse PFS compared with those in whom MRD was undetectable; however, PFS was longer in those with MRD levels <10-1 than in those with MRD levels above this threshold. Our observations provide additional support for the use of MRD as a surrogate end point for PFS in patients receiving FCR. In patients on indefinite ibrutinib-based therapy, PFS did not differ significantly by undetectable MRD status, whereas those with MRD <10-1 tended to have longer PFS, although continuation of ibrutinib would very likely be necessary to maintain treatment efficacy.

Topics: Adenine; Antineoplastic Combined Chemotherapy Protocols; Cyclophosphamide; Female; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Neoplasm, Residual; Piperidines; Prognosis; Progression-Free Survival; Protein Kinase Inhibitors; Rituximab; Treatment Outcome; Vidarabine

Topics: Adenine; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Disease-Free Survival; Female; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Piperidines; Survival Rate; Vidarabine

Topics: Adenine; Antineoplastic Combined Chemotherapy Protocols; Cyclophosphamide; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Piperidines; Progression-Free Survival; Pyrazoles; Pyrimidines; Rituximab; Vidarabine

Data regarding the efficacy of treatment with ibrutinib-rituximab, as compared with standard chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab, in patients with previously untreated chronic lymphocytic leukemia (CLL) have been limited.. In a phase 3 trial, we randomly assigned (in a 2:1 ratio) patients 70 years of age or younger with previously untreated CLL to receive either ibrutinib and rituximab for six cycles (after a single cycle of ibrutinib alone), followed by ibrutinib until disease progression, or six cycles of chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab. The primary end point was progression-free survival, and overall survival was a secondary end point. We report the results of a planned interim analysis.. A total of 529 patients underwent randomization (354 patients to the ibrutinib-rituximab group, and 175 to the chemoimmunotherapy group). At a median follow-up of 33.6 months, the results of the analysis of progression-free survival favored ibrutinib-rituximab over chemoimmunotherapy (89.4% vs. 72.9% at 3 years; hazard ratio for progression or death, 0.35; 95% confidence interval [CI], 0.22 to 0.56; P<0.001), and the results met the protocol-defined efficacy threshold for the interim analysis. The results of the analysis of overall survival also favored ibrutinib-rituximab over chemoimmunotherapy (98.8% vs. 91.5% at 3 years; hazard ratio for death, 0.17; 95% CI, 0.05 to 0.54; P<0.001). In a subgroup analysis involving patients without immunoglobulin heavy-chain variable region (. The ibrutinib-rituximab regimen resulted in progression-free survival and overall survival that were superior to those with a standard chemoimmunotherapy regimen among patients 70 years of age or younger with previously untreated CLL. (Funded by the National Cancer Institute and Pharmacyclics; E1912 ClinicalTrials.gov number, NCT02048813.).

Topics: Adenine; Aged; Antineoplastic Combined Chemotherapy Protocols; Cyclophosphamide; Female; Humans; Immunotherapy; Intention to Treat Analysis; Kaplan-Meier Estimate; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Piperidines; Progression-Free Survival; Pyrazoles; Pyrimidines; Rituximab; Vidarabine

Early phase studies of alvocidib showed activity in relapsed CLL including patients with high risk genomic features and those refractory to fludarabine. A multi-center, international, phase II study of alvocidib in fludarabine refractory CLL was undertaken to validate these early results. Patients with fludarabine refractory CLL or prolymphocytic leukemia arising from CLL were treated with single agent alvocidib. The primary outcome measure was overall response rate, with secondary outcomes including survival, toxicity, and response duration. One hundred and sixty five patients were enrolled and 159 patients were treated. The median age was 61 years, the median number of prior therapies was 4, and 96% of patients were fludarabine refractory. The investigator-assessed overall response rate was 25%; the majority of responses were partial. Response rates were lower among patients with del(17p) (14%), but equivalent in patients with del(11q) or bulky lymphadenopathy. Median progression free and overall survival were 7.6 and 14.6 months, respectively. Tumor lysis occurred in 39 patients (25%), and 13 received hemodialysis. Diarrhea, fatigue, and hematologic toxicities were common. Alvocidib has clinical activity in patients with advanced, fludarabine refractory CLL. Future studies should focus on discovery of biomarkers of clinical response and tumor lysis, and enhanced supportive care measures.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Female; Flavonoids; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Piperidines; Recurrence; Survival Analysis; Treatment Failure; Vidarabine

Flavopiridol downmodulates antiapoptotic proteins associated with resistance to fludarabine and rituximab and is effective against p53-mutated chronic lymphocytic leukemia (CLL). We conducted a phase I study of flavopiridol, fludarabine, and rituximab (FFR) in patients with mantle-cell lymphoma (MCL), indolent B-cell non-Hodgkin's lymphomas (B-NHL), and CLL to determine the activity of FFR.. Therapy included fludarabine 25 mg/m(2) intravenously (IV) days 1 to 5 and rituximab 375 mg/m(2) day 1 every 28 days for 6 cycles. We administered flavopiridol 50 mg/m(2) by 1-hour IV bolus (IVB) day 1 (n = 15); day 1 to 2 (n = 6); 20 mg/m(2) 30-minute IVB + 20 mg/m(2) 4-hour IV infusion (n = 3); or 30 mg/m(2) + 30 mg/m(2) (n = 14).. Thirty-eight patients (median age, 62 years) with MCL (n = 10); indolent B-NHL including follicular (n = 9), marginal zone (n = 4), lymphoplasmacytic (n = 1), or small lymphocytic lymphoma (n = 3); and CLL (n = 11), were enrolled. Twenty-two patients were previously untreated; 16 had received one to two prior therapies. Two patients in cohort 2 developed grade 3 dose-limiting toxicity (seizures, renal insufficiency). The median number of treatment cycles was 4, with cytopenias (n = 10) and fatigue (n = 3) the most common reasons for early discontinuation. Overall response rate was 82% (complete response, 50%; unconfirmed complete response, 5%; partial response, 26%), including 80% of patients with MCL (median age, 68; seven complete responses, one partial response). Median progression-free survival (PFS) was 25.6 months. Median PFS of patients with nonblastoid variant MCL (n = 8) was 35.9 months.. FFR was active in MCL, indolent B-NHL, and CLL and should be studied for older patients with MCL who are not candidates for aggressive chemotherapy.

Topics: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; B-Lymphocytes; Female; Flavonoids; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma, B-Cell; Lymphoma, Mantle-Cell; Lymphoproliferative Disorders; Male; Middle Aged; Piperidines; Rituximab; Vidarabine

We previously reported interim results of a phase 1 trial in patients with chronic lymphocytic leukemia (CLL) whereby flavopiridol was administered intravenously as a 30-minute bolus followed by 4-hour infusion. We now report full pharmacokinetic (PK) data, correlations of PK with clinical outcomes, and final response and progression-free survival (PFS). Twenty-one (40%) of 52 patients with relapsed CLL achieved a partial response (PR) with a median PFS of 12 months. Responders included 17 (40%) of 43 fludarabine refractory patients, 7 (39%) of 18 patients with del(17p13), and 14 (74%) of 19 patients with del(11q22). Six responders received repeat therapy at relapse, and 5 responded again with a second median PFS of 10 months. Noncompartmental analysis and nonlinear mixed effects modeling was used to estimate PK parameters and evaluate covariates. Two-compartment population parameter estimates were 31.4 L/h, 65.8 L, 8.49 L/h, and 157 L for CL, V1, Q, and V2, respectively. Flavopiridol area under the plasma concentration-time curve (AUC) correlated with clinical response and cytokine release syndrome, and glucuronide metabolite AUC correlated with tumor lysis syndrome. These composite results confirm high activity of this pharmacokinetically derived schedule in relapsed, genetically high-risk CLL. Furthermore, PK describes some, but not all, variability in response and toxicity.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Area Under Curve; Cell Cycle; Disease-Free Survival; Drug Resistance, Neoplasm; Female; Flavonoids; Humans; Inactivation, Metabolic; Infusions, Intravenous; Injections, Intravenous; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Models, Biological; Piperidines; Protein Kinase Inhibitors; Recurrence; Salvage Therapy; Treatment Outcome; Tumor Lysis Syndrome; Uridine Diphosphate Glucuronic Acid; Vidarabine

Topics: Adenine; Antineoplastic Combined Chemotherapy Protocols; Bendamustine Hydrochloride; Bortezomib; Chlorambucil; Cyclophosphamide; Dexamethasone; Doxorubicin; Humans; Kaplan-Meier Estimate; Piperidines; Prednisone; Progression-Free Survival; Proportional Hazards Models; Retrospective Studies; Rituximab; Treatment Outcome; Veterans; Vidarabine; Vincristine; Waldenstrom Macroglobulinemia

We performed a retrospective study comparing treatment patterns and overall survival (OS) in chronic lymphocytic leukemia (CLL) patients with the advent of ibrutinib to provide current real-world data.. Using a provincial population-based database, we analyzed CLL patients who received upfront treatment in British Columbia before ibrutinib availability (1984-2014), during ibrutinib access for: relapse only (2014-2015) and for upfront treatment of patients (with 17p deletion or unfit for chemotherapy) (2015-2016). Analysis included up to third-line treatment.. Of 1729 patients meeting inclusion criteria (median age, 66 years; 1466, period 1; 140, period 2; 123, period 3), FR was the most common first-line therapy (35.8 %, 54.3 % and 40.7 %, periods 1-3, respectively) and 18.7 % received ibrutinib upfront in period 3. The most common therapies in relapse were chemoimmunotherapy (36.1 % and 55.6 %, periods 1 and 2, second-line; 29.2 %, period 1, third-line) and ibrutinib (69.8 %, period 3, second-line; 46.4 % and 70.3 %, periods 2 and 3, third-line). OS improved for patients treated in periods 2-3 over period 1 (median OS not reached vs. 11.9 years, p < 0.001; no difference in OS for periods 2-3, p = 0.385).. Ibrutinib has replaced chemoimmunotherapy as the preferred therapy in relapse. Overall survival has improved over time with access to ibrutinib.

Topics: Adenine; Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; British Columbia; Chromosome Deletion; Chromosomes, Human, Pair 17; Cyclophosphamide; Disease Management; Doxorubicin; Female; Hematopoietic Stem Cell Transplantation; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Neoplasm, Residual; Piperidines; Prednisone; Prognosis; Pyrazoles; Pyrimidines; Recurrence; Remission Induction; Retrospective Studies; Rituximab; Smith-Magenis Syndrome; Survival Analysis; Transplantation, Homologous; Treatment Outcome; Vidarabine; Vincristine

High UGT2B17 is associated with poor prognosis in untreated chronic lymphocytic leukaemia (CLL) patients and its expression is induced in non-responders to fludarabine-containing regimens. We examined whether UGT2B17, the predominant lymphoid glucuronosyltransferase, affects leukaemic drug response and is involved in the metabolic inactivation of anti-leukaemic agents.. Functional enzymatic assays and patients' plasma samples were analysed by mass-spectrometry to evaluate drug inactivation by UGT2B17. Cytotoxicity assays and RNA sequencing were used to assess drug response and transcriptome changes associated with high UGT2B17 levels.. High UGT2B17 in B-cell models led to reduced sensitivity to fludarabine, ibrutinib and idelalisib. UGT2B17 expression in leukaemic cells involved a non-canonical promoter and was induced by short-term treatment with these anti-leukaemics. Glucuronides of both fludarabine and ibrutinib were detected in CLL patients on respective treatment, however UGT2B17 conjugated fludarabine but not ibrutinib. AMP-activated protein kinase emerges as a pathway associated with high UGT2B17 in fludarabine-treated patients and drug-treated cell models. The expression changes linked to UGT2B17 exposed nuclear factor kappa B as a key regulatory hub.. Data imply that UGT2B17 represents a mechanism altering drug response in CLL through direct inactivation but would also involve additional mechanisms for drugs not inactivated by UGT2B17.

Topics: Adenine; Antineoplastic Combined Chemotherapy Protocols; B-Lymphocytes; Biomarkers, Pharmacological; Female; Gene Expression Regulation, Neoplastic; Glucuronosyltransferase; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Mass Spectrometry; Middle Aged; Minor Histocompatibility Antigens; NF-kappa B; Piperidines; Purines; Quinazolinones; Vidarabine

Using next-generation sequencing (NGS), we recently documented T-cell oligoclonality in treatment-naïve chronic lymphocytic leukemia (CLL), with evidence indicating T-cell selection by restricted antigens.. Here, we sought to comprehensively assess T-cell repertoire changes during treatment in relation to (i) treatment type [fludarabine-cyclophosphamide-rituximab (FCR) versus ibrutinib (IB) versus rituximab-idelalisib (R-ID)], and (ii) clinical response, by combining NGS immunoprofiling, flow cytometry, and functional bioassays.. T-cell clonality significantly increased at (i) 3 months in the FCR and R-ID treatment groups, and (ii) over deepening clinical response in the R-ID group, with a similar trend detected in the IB group. Notably, in constrast to FCR that induced T-cell repertoire reconstitution, B-cell receptor signaling inhibitors (BcRi) preserved pretreatment clones. Extensive comparisons both within CLL as well as against T-cell receptor sequence databases showed little similarity with other entities, but instead revealed major clonotypes shared exclusively by patients with CLL, alluding to selection by conserved CLL-associated antigens. We then evaluated the functional effect of treatments on T cells and found that (i) R-ID upregulated the expression of activation markers in effector memory T cells, and (ii) both BcRi improved antitumor T-cell immune synapse formation, in marked contrast to FCR.. Taken together, our NGS immunoprofiling data suggest that BcRi retain T-cell clones that may have developed against CLL-associated antigens. Phenotypic and immune synapse bioassays support a concurrent restoration of functionality, mostly evident for R-ID, arguably contributing to clinical response.

Topics: Adenine; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Clonal Evolution; Cohort Studies; Cyclophosphamide; Disease-Free Survival; Female; Humans; Immunological Synapses; Immunophenotyping; Leukemia, Prolymphocytic, T-Cell; Male; Middle Aged; Piperidines; Purines; Quinazolinones; Rituximab; T-Lymphocytes; Vidarabine

After analyzing treatment patterns in chronic lymphocytic leukemia (CLL) (objective 1), we investigated the relative effectiveness of ibrutinib versus other commonly used treatments (objective 2) in patients with treatment-naïve and relapsed/refractory CLL, comparing patient-level data from two randomized registration trials with two real-world databases. Hazard ratios (HR) and 95% confidence intervals (CIs) were estimated using a multivariate Cox proportional hazards model, adjusted for differences in baseline characteristics. Rituximab-containing regimens were often prescribed in clinical practice. The most frequently prescribed regimens were fludarabine + cyclophosphamide + rituximab (FCR, 29.3%), bendamustine + rituximab (BR, 17.7%), and other rituximab-containing regimens (22.0%) in the treatment-naïve setting (n = 604), other non-FCR/BR rituximab-containing regimens (38.7%) and non-rituximab-containing regimens (28.5%) in the relapsed/refractory setting (n = 945). Adjusted HRs (95% CI) for progression-free survival (PFS) and overall survival (OS), respectively, with ibrutinib versus real-world regimens were 0.23 (0.14-0.37; p < 0.0001) and 0.40 (0.22-0.76; p = 0.0048) in the treatment-naïve setting, and 0.21 (0.16-0.27; p < 0.0001) and 0.29 (0.21-0.41; p < 0.0001) in the relapsed/refractory setting. When comparing real-world use of ibrutinib (n = 53) versus other real-world regimens in relapsed/refractory CLL (objective 3), adjusted HRs (95% CI) were 0.37 (0.22-0.63; p = 0.0003) for PFS and 0.53 (0.27-1.03; p < 0.0624) for OS. This adjusted analysis, based on nonrandomized patient data, suggests ibrutinib to be more effective than other commonly used regimens for CLL.

Topics: Adenine; Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Bendamustine Hydrochloride; Cyclophosphamide; Databases, Factual; Disease-Free Survival; Female; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Piperidines; Pyrazoles; Pyrimidines; Rituximab; Survival Rate; Vidarabine

Topics: Adenine; Antineoplastic Combined Chemotherapy Protocols; Bridged Bicyclo Compounds, Heterocyclic; Clinical Trials as Topic; Cyclophosphamide; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Neoplasm Proteins; Patient Selection; Piperidines; Progression-Free Survival; Protein Kinase Inhibitors; Pyrazoles; Pyrimidines; Rituximab; Sulfonamides; Treatment Outcome; Vidarabine

Topics: Adenine; Cyclophosphamide; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Piperidines; Pyrazoles; Pyrimidines; Rituximab; Vidarabine

Ibrutinib (ibr) monotherapy and the combination of obinutuzumab plus chlorambucil (obi) are approved for previously untreated chronic lymphocytic leukemia (CLL). No trials directly comparing their efficacy are available. Therefore a matching-adjusted indirect comparison (MAIC) was performed to provide insight into their relative efficacy in terms of progression-free survival (PFS) and overall survival (OS). MAIC attempts to adjust for between-trial differences in factors known or suspected to influence treatment effects, to minimize bias.. A MAIC within a Bayesian framework was conducted using individual patient data from the RESONATE-2 study of ibr versus chlorambucil and published data from the CLL11 study of obi versus chlorambucil. Both studies were conducted in patients ineligible for full-dose fludarabine-based therapy. After matching, the reweighted adjusted relative efficacy measure of ibr versus chlorambucil from RESONATE-2 [hazard ratio (HR), 95% credible interval (CrI)] was compared with that of obi versus chlorambucil from CLL11 for each endpoint, using a Bayesian indirect comparison.. Our results suggest that in a population with similar average baseline characteristics to CLL11, ibr would improve PFS and OS outcomes compared to obi. Before matching, the HRs for ibr versus obi were 0.48 [CrI = 0.22-1.02, p(HR <1) = 97%], 0.85 [CrI = 0.44-1.63, p(HR <1) = 69%], and 0.40 [CrI = 0.10-1.54, p(HR <1) = 91%] for PFS by investigator assessment, PFS by independent review committee, and OS, respectively. After matching on all available characteristics the HRs decreased to 0.12 [CrI = 0.02-0.97, p(HR <1) = 98%], 0.24 [CrI = 0.04-1.35, p(HR <1) = 95%], and 0.21 [CrI = <0.01-8.89, p(HR <1) = 79%], respectively. There was a large variance around the treatment effect for OS due to the low number of deaths.. Our analysis suggests that ibrutinib is highly likely to provide greater PFS benefit than obinutuzumab plus chlorambucil in older or less fit patients with previously untreated CLL. There is also an indication of improvement in OS, albeit with a higher uncertainty due to the low number of events.. Janssen-Cilag Ltd.

Topics: Adenine; Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal, Humanized; Antineoplastic Agents, Alkylating; Bayes Theorem; Chlorambucil; Disease-Free Survival; Female; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Piperidines; Proportional Hazards Models; Pyrazoles; Pyrimidines; Vidarabine

Central nervous system involvement (CNSi) is a rare and poorly reported complication of chronic lymphocytic leukaemia (CLL). Establishing cause and effect between the CLL and the neurological symptoms remains challenging. We have analysed a retrospective cohort of 30 CLL patients with CNSi, documented by lymphocytic infiltration either by flow cytometry of the cerebrospinal fluid (CSF; n = 29) or CNS biopsy (n = 1). Neurological symptoms were heterogeneous. At the time of CNSi, less than half of the patients had a progressive CLL and 20 had never been treated for CLL. Initial treatment with fludarabine-based immuno-chemotherapy, with or without intra-CSF therapy, led to durable response in eight out of nine untreated patients. In contrast, 50% patients receiving various prior treatments needed additional therapy within a median of 4 months (1-16). Ibrutinib led to complete response in 4/4 heavily pre-treated patients. From CNSi, 5-year overall survival was 72% and 48% for treatment-naïve and previously treated patients respectively (P = 0·06); 5-year progression-free survival (PFS) was 43% and 0% (P = 0·125). 17p deletion was significantly associated with poor PFS (P = 0·006). CNSi may be the only sign of progression of CLL and should be considered an initiation criterion of systemic treatment. Prognosis seemed to be related to CLL characteristics rather than to CNSi itself.

Topics: Adenine; Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Central Nervous System; Cohort Studies; Disease Management; Disease-Free Survival; Female; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Leukemic Infiltration; Male; Middle Aged; Neoplasm Invasiveness; Piperidines; Prognosis; Pyrazoles; Pyrimidines; Remission Induction; Retrospective Studies; Survival Analysis; Vidarabine

A high pretreatment β2 -microglobulin (B2M) level is associated with inferior survival outcomes in patients with chronic lymphocytic leukemia. However, to the authors' knowledge, the prognostic and predictive significance of changes in B2M during treatment have not been reported to date.. The authors analyzed 83 patients treated with ibrutinib-based regimens (66 with recurrent/refractory disease) and 198 treatment-naive patients who were treated with combined fludarabine, cyclophosphamide, and rituximab (FCR) to characterize changes in B2M and their relationship with clinical outcomes.. B2M rapidly decreased during treatment with ibrutinib; on multivariable analysis, patients who received FCR (odds ratio, 0.40; 95% confidence interval [95% CI], 0.18-0.90 [P = .027]) were less likely to have normalized B2M at 6 months than patients treated with ibrutinib. On univariable analysis, normalization of B2M was associated with superior progression-free survival (PFS) from the 6-month landmark in patients treated with ibrutinib-based regimens and FCR. On multivariable analysis, failure to achieve normalized B2M at 6 months of treatment was associated with inferior PFS (hazard ratio, 16.9; 95% CI, 1.3-220.0 [P = .031]) for patients treated with ibrutinib, after adjusting for the effects of baseline B2M, stage of disease, fludarabine-refractory disease, and del(17p). In contrast, in patients treated with FCR, negative minimal residual disease status in the bone marrow was the only variable found to be significantly associated with superior PFS (hazard ratio, 0.28; 95% CI, 0.12-0.67 [P = .004]).. Normalization of B2M at 6 months in patients treated with ibrutinib was found to be a useful predictor of subsequent PFS and may assist in clinical decision-making.

Topics: Adenine; Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Bendamustine Hydrochloride; beta 2-Microglobulin; Bone Marrow; Case-Control Studies; Chromosomes, Human, Pair 11; Chromosomes, Human, Pair 17; Cohort Studies; Cyclophosphamide; Disease-Free Survival; Female; Humans; Immunoglobulin Heavy Chains; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Neoplasm, Residual; Piperidines; Prognosis; Proportional Hazards Models; Pyrazoles; Pyrimidines; Retrospective Studies; Rituximab; Treatment Outcome; Vidarabine; ZAP-70 Protein-Tyrosine Kinase

Topics: Adenine; Antineoplastic Agents; Bendamustine Hydrochloride; Bortezomib; Chromosomes, Human, Pair 17; Cytarabine; Humans; Lenalidomide; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma, Mantle-Cell; Mutation; Neoplasm Recurrence, Local; Piperidines; Pyrazoles; Pyrimidines; Rituximab; Sirolimus; Thalidomide; Tumor Suppressor Protein p53; Vidarabine

Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Alemtuzumab; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Disease Progression; Disease-Free Survival; Gene Expression Regulation, Leukemic; Humans; Immunotherapy; Kaplan-Meier Estimate; Leukemia, Lymphocytic, Chronic, B-Cell; MicroRNAs; Multivariate Analysis; Piperidines; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; Rituximab; Treatment Outcome; Vidarabine

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in the Western world. Median age at diagnosis is around 70 years. To confirm the diagnosis more than 5000 B-lymphocytes/µl need to be present. The expression of the typical surface markers CD5, CD19, CD20 and CD23 has to be confirmed by flow cytometry. A bone marrow biopsy is not mandatory for the diagnosis. Before start of treatment the assessment of 17 p deletion and/or TP53-mutational status is recommended. Treatment indications include stage Binet C or signs of an active disease as rapidly progressive lymphadenopathy or organomegaly together with physical limitation, B symptoms that cannot be tolerated, rapidly deteriorating blood values, or rapidly increasing leukocyte counts (Lymphocyte doubling time less than 6 months). The patient's physical condition has major impact on the treatment decision. Currently immunochemotherapy with fludarabine, cyclophosphamide and the CD20-antibody rituximab (FCR) is the standard of care in previously untreated and physically fit patients. An alternative regimen is the combination of bendamustine and rituximab (BR) or ofatumumab. Physically compromised patients can be treated with the oral drug chlorambucil in combination with an anti-CD20 antibody. Due to high morbidity and mortality, allogeneic stem cell transplantation is limited to a small group of patients and should be discussed in a high-risk situation, such as 17 p deletion and/or TP53-mutation, lack of response to standard therapy or early relapse. Recently several new chemo-free treatment options have been introduced within clinical trials. Among them are monoclonal antibodies, most of them targeting the CD20 molecule: besides the licensed drugs rituximab and ofatumumab, obinutuzumab, in combination with chemotherapy, has recently shown high clinical efficacy in front-line treatment of elderly patients with CLL. Novel agents have been designed to block aberrant signaling from the B-cell receptor. Ibrutinib acts by inhibiting the Bruton's tyrosine kinase (BTK) while idelalisib represents a first-in-class specific inhibitor of the phosphoinositol-3 kinase (PI3K) delta isoform. Another class of drugs with potential impact for chemo-free treatment strategies in CLL is the BH3-mimetic inhibitor of the Bcl-2 family of pro-survival proteins, ABT-199. Given all these novel agents and targets, chemo-free or at least chemo-reduced concepts may become reality in the near future for our patients suf

Topics: Adenine; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Combined Chemotherapy Protocols; Cyclophosphamide; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Piperidines; Purines; Pyrazoles; Pyrimidines; Quinazolinones; Remission Induction; Rituximab; Vidarabine

Waldenström macroglobulinemia (WM) is a B-cell neoplasm manifested by the accumulation of clonal immunoglobulin (Ig)M-secreting lymphoplasmacytic cells. MYD88 and CXCR4 warts, hypogammaglobulinemia, infections, myelokathexis syndrome-like somatic mutations are present in >90% and 30% to 35% of WM patients, respectively, and impact disease presentation, treatment outcome, and overall survival. Familial predisposition is common in WM. Asymptomatic patients should be observed. Patients with disease-related hemoglobin <10 g/L, platelets <100 × 10(9)/L, bulky adenopathy and/or organomegaly, symptomatic hyperviscosity, peripheral neuropathy, amyloidosis, cryoglobulinemia, cold-agglutinin disease, or transformed disease should be considered for therapy. Plasmapheresis should be used for patients with symptomatic hyperviscosity and before rituximab for those with high serum IgM levels to preempt a symptomatic IgM flare. Treatment choice should take into account specific goals of therapy, necessity for rapid disease control, risk of treatment-related neuropathy, immunosuppression and secondary malignancies, and planning for future autologous stem cell transplantation. Frontline treatments include rituximab alone or rituximab combined with alkylators (bendamustine and cyclophosphamide), proteasome inhibitors (bortezomib and carfilzomib), nucleoside analogs (fludarabine and cladribine), and ibrutinib. In the salvage setting, an alternative frontline regimen, ibrutinib, everolimus, or stem cell transplantation can be considered. Investigational therapies under development for WM include agents that target MYD88, CXCR4, BCL2, and CD27/CD70 signaling, novel proteasome inhibitors, and chimeric antigen receptor-modified T-cell therapy.

Topics: Adenine; Adult; Aged; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Combined Chemotherapy Protocols; B-Lymphocytes; Bendamustine Hydrochloride; Boronic Acids; Bortezomib; Cladribine; Cyclophosphamide; Everolimus; Gene Expression; Genetic Predisposition to Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunoglobulin M; Male; Middle Aged; Molecular Targeted Therapy; Myeloid Differentiation Factor 88; Nitrogen Mustard Compounds; Oligopeptides; Piperidines; Plasmapheresis; Pyrazines; Pyrazoles; Pyrimidines; Receptors, CXCR4; Rituximab; Sirolimus; Transplantation, Autologous; Vidarabine; Waldenstrom Macroglobulinemia

Leukemic cells from Chronic Lymphocytic Leukemia (CLL) patients interact with stromal cells of the surrounding microenvironment. Mesenchymal Stromal Cells (MSCs) represent the main population in CLL marrow stroma, which may play a key role for disease support and progression. In this study we evaluated whether MSCs influence in vitro CLL cell survival. MSCs were isolated from the bone marrow of 46 CLL patients and were characterized by flow cytometry analysis. Following co-culture of MSCs and leukemic B cells, we demonstrated that MSCs were able to improve leukemic B cell viability, this latter being differently dependent from the signals coming from MSCs. In addition, we found that the co-culture of MSCs with leukemic B cells induced an increased production of IL-8, CCL4, CCL11, and CXCL10 chemokines.As far as drug resistance is concerned, MSCs counteract the cytotoxic effect of Fludarabine/Cyclophosphamide administration in vivo, whereas they do not protect CLL cells from the apoptosis induced by the kinase inhibitors Bafetinib and Ibrutinib. The evidence that leukemic clones are conditioned by environmental stimuli suggest new putative targets for therapy in CLL patients.

Topics: Adenine; Aged; Antineoplastic Agents; Apoptosis; Bone Marrow Cells; Cell Communication; Cell Survival; Cells, Cultured; Coculture Techniques; Cyclophosphamide; Cytokines; Drug Resistance, Neoplasm; Female; Humans; Immunoblotting; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Mesenchymal Stem Cells; Middle Aged; Piperidines; Protein Kinase Inhibitors; Pyrazoles; Pyrimidines; Vidarabine

Topics: Adenine; Antineoplastic Agents; Casein Kinase II; Drug Synergism; Hematologic Neoplasms; Humans; Immunoglobulin G; Leukemia, Lymphocytic, Chronic, B-Cell; Naphthyridines; Phenazines; Piperidines; Prognosis; Purines; Pyrazoles; Pyrimidines; Quinazolinones; Receptors, Antigen, B-Cell; Signal Transduction; Vidarabine

Cyclin dependent kinase (CDK) inhibitors, such as flavopiridol, demonstrate significant single-agent activity in chronic lymphocytic leukemia (CLL), but the mechanism of action in these nonproliferating cells is unclear. Here we demonstrate that CLL cells undergo autophagy after treatment with therapeutic agents, including fludarabine, CAL-101, and flavopiridol as well as the endoplasmic reticulum (ER) stress-inducing agent thapsigargin. The addition of chloroquine or siRNA against autophagy components enhanced the cytotoxic effects of flavopiridol and thapsigargin, but not the other agents. Similar to thapsigargin, flavopiridol robustly induces a distinct pattern of ER stress in CLL cells that contributes to cell death through IRE1-mediated activation of ASK1 and possibly downstream caspases. Both autophagy and ER stress were documented in tumor cells from CLL patients receiving flavopiridol. Thus, CLL cells undergo autophagy after multiple stimuli, including therapeutic agents, but only with ER stress mediators and CDK inhibitors is autophagy a mechanism of resistance to cell death. These findings collectively demonstrate, for the first time, a novel mechanism of action (ER stress) and drug resistance (autophagy) for CDK inhibitors, such as flavopiridol in CLL, and provide avenues for new therapeutic combination approaches in this disease.

Topics: Antineoplastic Agents; Autophagy; Cell Culture Techniques; Cyclin-Dependent Kinases; Drug Resistance, Neoplasm; Endoplasmic Reticulum Stress; Flavonoids; Gene Expression Regulation, Leukemic; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Piperidines; Protein Kinase Inhibitors; Signal Transduction; Starvation; Tumor Cells, Cultured; Vidarabine

Topics: Animals; Antineoplastic Agents; Disease Models, Animal; Disease Progression; Flavonoids; Gene Expression Regulation, Leukemic; Humans; Leukemia; Mice; MicroRNAs; Piperidines; Prognosis; Vidarabine

Flavopiridol, a synthetic flavone, is currently under clinical investigation for the treatment of B-cell chronic lymphocytic leukaemia (B-CLL). In this study, we examined the in vitro effects of flavopiridol and fludarabine on B-CLL cells from 64 patients (36 treated and 28 untreated) in terms of apoptosis induction and Bcl-2 family expression. Both flavopiridol and fludarabine induced apoptosis in all the samples tested with mean LD(50) values (+/- SD) of 59.7 nmol/l (+/- 36.5) and 6.2 micromol/l (+/- 7.5) respectively. Mean flavopiridol LD(50) values were not significantly different between the treated and untreated patient groups (P = 0.35), whereas the fludarabine LD(50) values were significantly higher in the previously treated patient group (P = 0.01). Bcl-2 and Mcl-1 expression were downregulated in both flavopiridol and fludarabine-induced apoptotic cells, but the increase in Bax expression that accompanied fludarabine-induced apoptosis was not evident in flavopiridol-treated cells. In addition, Bcl-2:Bax ratios were not predictive of flavopiridol cytotoxicity (P = 0.82), whereas they were highly predictive of in vitro responsiveness to fludarabine (P = 0.001). Overall, these findings suggest that flavopiridol exerts its cytotoxic effect through a novel cell-death pathway that is not subject to the Bcl-2 family mediated resistance mechanisms that reduce the efficacy of many conventional chemotherapeutic drugs.

Topics: Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Drug Resistance, Neoplasm; Flavonoids; Flow Cytometry; Humans; Lethal Dose 50; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphocytes; Piperidines; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Tumor Suppressor Protein p53; Vidarabine

Flavopiridol has been reported to induce apoptosis in lymphoid cell lines via downregulation of bcl-2. The in vitro activity of flavopiridol against human chronic lymphocytic leukemia (CLL) cells and potential mechanisms of action for inducing cytotoxicity were studied. The in vitro viability of mononuclear cells from CLL patients (n = 11) was reduced by 50% at 4 hours, 24 hours, and 4 days at a flavopiridol concentration of 1.15 micromol/L (95% confidence interval [CI] +/-0.31), 0.18 micromol/L (95% CI +/-0.04), and 0.16 micromol/L (95% CI +/-0.04), respectively. Loss of viability in human CLL cells correlated with early induction of apoptosis. Exposure of CLL cells to 0.18 micromol/L of flavopiridol resulted in both decreased expression of p53 protein and cleavage of the caspase-3 zymogen 32-kD protein with the appearance of its 20-kD subunit. Contrasting observations of others in tumor cell lines, flavopiridol cytotoxicity in CLL cells did not correlate with changes in bcl-2 protein expression alterations. We evaluated flavopiridol's dependence on intact p53 by exposing splenocytes from wild-type (p53(+/+)) and p53 null (p53(-/-)) mice that demonstrated no preferential cytotoxicity as compared with a marked differential with F-ara-a and radiation. Incubation of CLL cells with antiapoptotic cytokine interleukin-4 (IL-4) did not alter the LC50 of flavopiridol, as compared with a marked elevation noted with F-ara-a in the majority of patients tested. These data demonstrate that flavopiridol has significant in vitro activity against human CLL cells through activation of caspase-3, which appears to occur independently of bcl-2 modulation, the presence of IL-4, or p53 status. Such findings strongly support the early introduction of flavopiridol into clinical trials for patients with B-CLL.

Topics: Animals; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspases; Cell Cycle Proteins; Chromosomes, Human, Pair 17; Cyclin-Dependent Kinase Inhibitor p27; Drug Administration Schedule; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Enzyme Activation; Enzyme Precursors; Flavonoids; Gene Deletion; Genes, p53; Growth Inhibitors; Humans; In Situ Hybridization, Fluorescence; Interleukin-4; Leukemia, Lymphocytic, Chronic, B-Cell; Mice; Mice, Inbred C57BL; Mice, Knockout; Microtubule-Associated Proteins; Neoplasm Proteins; Piperidines; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Tumor Cells, Cultured; Tumor Suppressor Protein p53; Tumor Suppressor Proteins; Vidarabine