Kanti R. Rai

Randomized Phase III Trial of Fludarabine Plus Cyclophosphamide With or Without Oblimersen Sodium (Bcl-2 antisense) in Patients With Relapsed or Refractory Chronic Lymphocytic Leukemia

PURPOSE Expression of Bcl-2 protein is associated with chemotherapy resistance and decreased survival in chronic lymphocytic leukemia (CLL). We evaluated whether oblimersen would improve response to chemotherapy in patients with relapsed or refractory CLL. PATIENTS AND METHODS Patients had received at least one prior fludarabine-containing regimen and were stratified on the basis of prior fludarabine response, number of prior regimens, and duration of response to last prior therapy. Patients were randomly assigned to 28-day cycles of fludarabine 25 mg/m2/d plus cyclophosphamide 250 mg/m2/d administered intravenously for 3 days with or without oblimersen 3 mg/kg/d as a 7-day continuous intravenous infusion (beginning 4 days before chemotherapy) for up to six cycles. The primary end point was the proportion of patients who achieved complete response (CR) or nodular partial response (nPR). RESULTS Of 241 patients randomly assigned, CR/nPR was achieved in 20 (17%) of 120 patients in the oblimersen group and eight (7%) of 121 patients in the chemotherapy-only group (P = .025). Achievement of CR/nPR was correlated with both an extended time to progression and survival (P < .0001). In patients who remained sensitive to fludarabine, oblimersen was associated with a four-fold increase in the CR/nPR rate and a significant survival benefit (P = .05). Oblimersen was frequently associated with thrombocytopenia and, rarely, tumor lysis syndrome and cytokine release reactions; the incidence of opportunistic infections and second malignancies was similar in both groups. CONCLUSION The addition of oblimersen to fludarabine plus cyclophosphamide significantly increases the CR/nPR rate in patients with relapsed or refractory CLL (particularly fludarabine-sensitive patients), as well as response duration among patients who achieve CR/nPR.

Chronic Lymphocytic Leukaemia: Proposals for a Revised Prognostic Staging System

In the past the clinical course of chronic lymphocytic leukaemia (CLL) has been considered to be highly variable primarily due to a lack of understanding of prognostic factors. In the mid-1’370s Rai et al (1975) developed a simple staging system based on easily obtainable clinical and haematological data. The validity of the Rai clinical staging classification to predict the expected duration of survival of CLL patients has been confirmed by a number of subsequent publications (Phillips et al, 1977; Binet et al, 1977; Dighiero et al, 1979; Santoro et al, 1979; Rundles & Moore, 1978; Montserrat et al, 1977). This staging system brought a new perspective to clinical investigations in CLL by allowing the study of groups of patients of similar life expectancy in more comparable therapeutic trials. With use, certain limitations of the staging system have been recognized. The major inadequacies that have emerged requiring a revision of the system include: (1) the use of too many clinical groups (stages) making the design of useful therapeutic trials more difficult; and (2) a lack of consideration for the role of isolated organomegaly (e.g. splenomegaly or hepatomegaly) without lymphadenopathy in estimating the clinical prognosis of patients. An international workshop on CLL met in Paris in November 1979 and data on 295 patients were presented (Binet et al, 1981). In a second meeting in Montreal in August 1980 data on a larger number of patients were pooled. The outcome of a multivariatc analysis of more than 900 patients demonstrated three patterns of survival curves and the analysis resulted in a proposal for a new staging classification of CLL. Patients with anaemia (Hb < 10 g/dl) and/or thrombocytopenia ( < 100 x 10y/l) were found to have the poorest prognosis and were to be called group C. The prognosis of the remaining patients (approximately 80% of all the patients) was found to depend on the number of clinically relevant areas involved. Clinical enlargement of the spleen, the liver, and of lymph nodes in the cervical, axillary and inguinal regions constituted * Sponsored by the French National Cancer League and the National Leukemia Association, Inc. (U.S.A.). Participants: A. AUQUIER, Paris, France; J. BENNETT, Rochester, New York, U.S.A.; J.-L. BINET, Paris, France; K. BREMER, Essen, Germany; D. CATOVSKY, London, England; P. CHANDRA, Upton, New York, U.S.A.; C. CHASTANG, Paris, France; E. P. CRONKITE, Upton, New York, U.S.A.; G. DIGHIERO, Paris, France; D. A. G. GALTON, London, England; M. M. HANSEN, Copenhagen, Denmark; A. HUANG, Durham, N. Carolina, U.S.A.; C. JACQUILLAT, Paris, France; E. MONTSERRAT, Barcelona, Spain; H. PIGUET, Rouen, France; K. R . RAI, New Hyde Park, New York, U.S.A.; C. ROZMAN, Barcelona, Spain; W. RUNDLES, Durham, N. Carolina, U.S.A.; A. SAWITSKY, New Hyde Park, New York, U.S.A.; P. STRYCKMANS, Brussells, Belgium; C. SULTAN, Paris, France; M. WEIL, Paris, France. Correspondence: Dr A. Sawitsky, Long Island Jewish-Hillside Medical Center,. New Hyde Park, New York 11042, U.S.A.

Chronic lymphocytic leukemia cells recognize conserved epitopes associated with apoptosis and oxidation.

Chronic lymphocytic leukemia (CLL) represents the outgrowth of a CD5+ B cell. Its etiology is unknown. The structure of membrane Ig on CLL cells of unrelated patients can be remarkably similar. Therefore, antigen binding and stimulation could contribute to clonal selection and expansion as well as disease promotion. Initial studies suggest that CLL mAbs bind autoantigens. Since apoptosis can make autoantigens accessible for recognition by antibodies, and also create neo-epitopes by chemical modifications occurring naturally during this process, we sought to determine if CLL mAbs recognize autoantigens associated with apoptosis. In general, ~60% of CLL mAbs bound the surfaces of apoptotic cells, were polyreactive, and expressed unmutated IGHV. mAbs recognized two types of antigens: native molecules located within healthy cells, which relocated to the external cell surface during apoptosis; and/or neoantigens, generated by oxidation during the apoptotic process. Some of the latter epitopes are similar to those on bacteria and other microbes. Although most of the reactive mAbs were not mutated, the use of unmutated IGHV did not bestow autoreactivity automatically, since several such mAbs were not reactive. Particular IGHV and IGHV/D/J rearrangements contributed to autoantigen binding, although the presence and degree of reactivity varied based on specific structural elements. Thus, clonal expansion in CLL may be stimulated by autoantigens occurring naturally during apoptosis. These data suggest that CLL may derive from normal B cells whose function is to remove cellular debris, and also to provide a first line of defense against pathogens.

Rituximab-based chemotherapy for steroid-refractory autoimmune hemolytic anemia of chronic lymphocytic leukemia.

Autoimmune hemolytic anemia (AIHA) is a well known complication of chronic lymphocytic leukemia (CLL). Steroids are the first line of treatment and there are limited effective treatment options for steroid refractory AIHA of CLL. Rituximab, an active agent against B cell malignancies, has also been noted to be active in certain autoimmune hematologic disorders. We used a combination of rituximab, cyclophosphamide and dexamethasone (RCD) in eight CLL patients with steroid refractory AIHA. Rituximab was given at a dose of 375 mg/m2 i.v. on day 1 (D-1). Cyclophosphamide was given at a dose of 750 mg/m2 on D-2. Twelve mg of dexamethasone was given i.v. on D-1, D-2 and orally from D-3 to D-7. Cycles were repeated every 4 weeks till the best response. Response in AIHA was evaluated by frequent blood counts and Coombs test. All eight patients achieved a remission of their AIHA. Median pretreatment hemoglobin was 8.3 g/dl and post-treatment hemoglobin was 14.3 g/dl. Five patients converted to Coombs negative after RCD. Median duration of response was 13 months (7–23+). Retreatment with RCD was also effective in achieving a response on relapse of AIHA. Our results indicate that a rituximab-based combination regimen (RCD) is highly effective in treating steroid refractory AIHA of CLL.

Treatment of hairy-cell leukemia with cladribine: response, toxicity, and long-term follow-up.

PURPOSE To analyze initial and long-term outcomes after treatment of patients with active hairy-cell leukemia (HCL) with a single cycle of cladribine (2-CdA). PATIENTS AND METHODS Forty-nine patients with active HCL were treated with 2-CdA by continuous intravenous infusion at 0.1 mg/kg/d for a total of 7 days at the Long Island Jewish Medical Center between September 1990 and August 1992. Here we report on all patients followed-up until April 1996. RESULTS At 3 months after treatment, complete response (CR) occurred in 37 patients (76%) and partial response (PR) occurred in 12 patients (24%), for an overall response rate of 100% (95% confidence interval, 94% to 100%). At a median follow-up of 55 months, the relapse-free survival is 80% and overall survival is 95%. Ten patients (20%) have relapsed. Of the 26 patients in whom lymphocyte phenotyping was performed, four were found to have a CD25-negative phenotype. All four of these patients had PRs only and all relapsed. Eight patients have been re-treated with 2-CdA, and all achieved at least a partial remission; two of these have already relapsed with remission durations of less than 1 year. Five second malignancies have occurred in four patients. CONCLUSION With a median follow-up of more than 4 years, 39 patients (80%) continue in remission. Only two deaths have occurred. A CD25-negative phenotype may predict for a poorer response to 2-CdA. Patients who relapse may be re-treated with 2-CdA, but subsequent remissions may be of shorter duration. There has not been a markedly increased incidence of second malignancies or late opportunistic infections.

The Bruton tyrosine kinase inhibitor ibrutinib with chemoimmunotherapy in patients with chronic lymphocytic leukemia.

The safety and efficacy of ibrutinib, an oral inhibitor of Bruton tyrosine kinase, were evaluated with chemoimmunotherapy (CIT) in a multicenter phase 1b study. Patients with relapsed/refractory chronic lymphocytic leukemia received bendamustine and rituximab (BR) or fludarabine, cyclophosphamide, and rituximab (FCR) for up to 6 cycles with daily ibrutinib (420 mg) until progressive disease or unacceptable toxicity. Enrollment to FCR-ibrutinib closed early due to a lack of fludarabine-naïve previously treated patients. No patients treated with BR-ibrutinib (n = 30) or FCR-ibrutinib (n = 3) experienced prolonged hematologic toxicity in cycle 1 (primary end point). Tolerability was as expected with either CIT or single-agent ibrutinib. The overall response rate (ORR) with BR-ibrutinib was 93.3%, including 16.7% complete responses (CRs) initially, which increased to 40% with the extension period. Including 1 patient with partial response with lymphocytosis, the best ORR was 96.7%. Sixteen of 21 patients with baseline cytopenias had sustained hematologic improvement. At 12 and 36 months, 86.3% and 70.3% remained progression-free, respectively. All 3 patients treated with ibrutinib-FCR achieved CR. Ibrutinib may enhance CIT efficacy without additive toxicities, providing the rationale for studying this combination in an ongoing phase 3 trial. The study is registered to www.clinicaltrials.gov as #NCT01292135.

Intraclonal complexity in chronic lymphocytic leukemia: fractions enriched in recently born/divided and older/quiescent cells.

The failure of chemotherapeutic regimens to eradicate cancers often results from the outgrowth of minor subclones with more dangerous genomic abnormalities or with self-renewing capacity. To explore such intratumor complexities in B-cell chronic lymphocytic leukemia (CLL), we measured B-cell kinetics in vivo by quantifying deuterium (2H)-labeled cells as an indicator of a cell that had divided. Separating CLL clones on the basis of reciprocal densities of chemokine (C-X-C motif) receptor 4 (CXCR4) and cluster designation 5 (CD5) revealed that the CXCR4dimCD5bright (proliferative) fraction contained more 2H-labeled DNA and hence divided cells than the CXCR4brightCD5dim (resting) fraction. This enrichment was confirmed by the relative expression of two cell cycle-associated molecules in the same fractions, Ki-67 and minichromosome maintenance protein 6 (MCM6). Comparisons of global gene expression between the CXCR4dimCD5bright and CXCR4brightCD5dim fractions indicated higher levels of pro-proliferation and antiapoptotic genes and genes involved in oxidative injury in the proliferative fraction. An extended immunophenotype was also defined, providing a wider range of surface molecules characteristic of each fraction. These intraclonal analyses suggest a model of CLL cell biology in which the leukemic clone contains a spectrum of cells from the proliferative fraction, enriched in recently divided robust cells that are lymphoid tissue emigrants, to the resting fraction enriched in older, less vital cells that need to immigrate to lymphoid tissue or die. The model also suggests several targets preferentially expressed in the two populations amenable for therapeutic attack. Finally, the study lays the groundwork for future analyses that might provide a more robust understanding of the development and clonal evolution of this currently incurable disease.

BTK inhibition results in impaired CXCR4 chemokine receptor surface expression, signaling and function in chronic lymphocytic leukemia.

Bruton’s tyrosine kinase (BTK) is involved in the regulation of B-cell growth, migration and adhesion. The importance of BTK in cell trafficking is emphasized by the clonal contraction proceeded by lymphocytosis typical for the enzyme inhibitor, ibrutinib, in B-cell malignancies, including chronic lymphocytic leukemia (CLL). Here, we investigated BTK regulation of leukemic B-cell trafficking in a mouse model of aggressive TCL1 CLL-like disease. Inhibiting BTK by ibrutinib reduced surface membrane (sm) levels of CXCR4 but not CXCR5, CD49d and other adhesion/homing receptors. Decreased smCXCR4 levels resulted from blocking receptor signal transduction, which in turn aborted cycling from and to the membrane. This resulted in rapid re-distribution of CLL cells from spleens and lymph nodes into the circulation. CLL cells with impaired smCXCR4 from BTK inhibition failed to home to spleens. These functional changes mainly resulted from inhibition of CXCR4 phosphorylation at Ser339, mediated directly by blocking BTK enzymatic activity and indirectly by affecting the function of downstream targets PLCγ2 and PKCμ, and eventually synthesis of PIM-1 and BTK itself. Our data identify CXCR4 as a key regulator in BTK-mediated CLL-cell retention and have elucidated a complex set of not previously described mechanisms responsible for these effects.

Identification of outcome-correlated cytokine clusters in chronic lymphocytic leukemia

Individual cytokines and groups of cytokines that might represent networks in chronic lymphocytic leukemia (CLL) were analyzed and their prognostic values determined. Serum levels of 23 cytokines were measured in 84 patients and 49 age-matched controls; 17 levels were significantly elevated in patients. Unsupervised hierarchical bicluster analysis identified 3 clusters (CLs) of highly correlated but differentially expressed cytokines: CL1 (CXCL9, CXCL10, CXCL11, CCL3, CCL4, CCL19, IL-5, IL-12, and IFNγ), CL2 (TNFα, IL-6, IL-8, and GM-CSF), and CL3 (IL-1β, IL-2, IL-4, IL-15, IL-17, and IFNα). Combination scores integrating expression of CL1/CL2 or CL1/CL3 strongly correlated (P < .005) with time-to-first-treatment and overall survival (OS), respectively. Patients with the worst course had high CL1 and low CL2 or CL3 levels. Multivariate analysis revealed that CL1/CL2 combination score and immunoglobulin heavy chain variable region mutation status were independent prognostic indicators for time-to-first-treatment, whereas CL1/CL3 combination score and immunoglobulin heavy chain variable region mutation status were independent markers for OS. Thus, we identified groups of cytokines differentially expressed in CLL that are independent prognostic indicators of aggressive disease and OS. These findings indicate the value of multicytokine analyses for prognosis and suggest therapeutic strategies in CLL aimed at reducing CL1 and increasing CL2/CL3 cytokines.

Th17 and non-Th17 interleukin-17-expressing cells in chronic lymphocytic leukemia: delineation, distribution, and clinical relevance

Background The levels and clinical relevance of Th17 cells and other interleukin-17-producing cells have not been analyzed in chronic lymphocytic leukemia. The objective of this study was to quantify blood and tissue levels of Th17 and other interleukin-17-producing cells in patients with this disease and correlate blood levels with clinical outcome. Design and Methods Intracellular interleukin-17A was assessed in blood and splenic mononuclear cells from patients with chronic lymphocytic leukemia and healthy subjects using flow cytometry. Interleukin-17A-producing cells were analyzed in formalin-fixed, paraffin-embedded spleen and lymph node sections using immunohistochemistry and immunofluorescence. Results The absolute numbers of Th17 cells in peripheral blood mononuclear cells and the percentages of Th17 cells in spleen cell suspensions were higher in patients with chronic lymphocytic leukemia than in healthy subjects; in six out of eight paired chronic lymphocytic leukemia blood and spleen sample comparisons, Th17 cells were enriched in spleen suspensions. Circulating Th17 levels correlated with better prognostic markers and longer overall survival of the patients. Two “non-Th17” interleukin-17-expressing cells were identified in chronic lymphocytic leukemia spleens: proliferating cells of the granulocytic lineage and mature mast cells. Granulocytes and mast cells in normal spleens did not express interleukin-17. Conversely, both chronic lymphocytic leukemia and healthy lymph nodes contained similar numbers of interleukin-17+ mast cells as well as Th17 cells. Conclusions Th17 cells are elevated in chronic lymphocytic leukemia patients with better prognostic markers and correlate with longer survival. Furthermore, non-Th17 interleukin-17A-expressing cells exist in chronic lymphocytic leukemia spleens as maturing granulocytes and mature mast cells, suggesting that the microenvironmental milieu in leukemic spleens promotes the recruitment and/or expansion of Th17 and other IL-17-expressing cells. The pathophysiology of Th17 and non-Th17-interleukin-producing cells in chronic lymphocytic leukemia and their distributions and roles in this disease merit further study.