Leukemia-cell proliferation and disease progression in patients with early stage chronic lymphocytic leukemia

The clinical course of patients with recently diagnosed early stage chronic lymphocytic leukemia (CLL) is highly variable. We examined the relationship between CLL-cell birth rate and treatment-free survival (TFS) in 97 patients with recently diagnosed, Rai stage 0–II CLL in a blinded, prospective study, using in vivo²H₂O labeling. Birth rates ranged from 0.07–1.31% new cells per day. With median follow-up of 4.0 years, 33 subjects (34%) required treatment by NCI criteria. High birth rate was observed in 44% of subjects and was significantly associated with shorter TFS, unmutated IGHV status, and expression of ZAP70 and of CD38. In multivariable modeling considering age, gender, Rai stage, expression of ZAP70 or CD38, IGHV mutation status and FISH cytogenetics, only CLL-cell birth rate and IGHV mutation status met criteria for inclusion. Hazard ratios were 3.51 (p=0.002) for high birth rate and 4.93 (p<0.001) for unmutated IGHV. The association between elevated birth rate and shorter TFS was observed in subjects with either mutated or unmutated IGHVs, and the use of both markers was a better predictor of TFS than either parameter alone. Thus, an increased CLL birth rate in early stage disease is a strong predictor of disease progression and earlier treatment.

A phase III, randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of idelalisib (GS-1101) in combination with bendamustine and rituximab for previously treated chronic lymphocytic leukemia (CLL)

TPS7133

Background: PI3K-delta is critical for the activation, proliferation and survival of B cells and plays a role in homing and retention of B cells in lymphoid tissues. PI3Kδ signaling is hyperactive in many B-cell malignancies. Idelalisib is a first-in-class, selective, oral inhibitor of PI3Kδ that reduces proliferation, enhances apoptosis, and alters trafficking of malignant B cells in lymphoid tissues (Lannutti, 2011). Phase 1 trials demonstrated that idelalisib is highly active in heavily pretreated pts with CLL as a single agent or in combination with rituximab (R), bendamustine (B), or BR: pts experienced reductions in disease-associated chemokines, profound and rapid reductions in lymphadenopathy, and durable clinical benefit with an acceptable safety profile (Coutre et al, 2012; Sharman et al, 2011). Methods: Study will enroll 390 pts with previously treated CLL who have measurable lymphadenopathy, have received prior therapy containing a purine analog or B and an anti-CD20 monoclonal antibody, are not refractory to B, have experienced CLL progression within 36 months from the completion of the last prior therapy, and are currently sufficiently fit to receive cytotoxic therapy. Pts are randomized in a 1:1 ratio to Arm A or B. On Arm A, subjects receive idelalisib continuously at 150 mg BID + R at 375 mg/m2 (1st dose) and then 500 mg/m2 every 4 weeks for 6 cycles + B at 70 mg/m2 on Days 1 and 2 of each 4-week cycle for 6 cycles. On Arm B, subjects receive placebo instead of idelalisib. Stratification factors address IGHV mutational status, del(17p)/p53 mutation status, and refractory vs relapsed disease. The primary endpoint is PFS and key secondary endpoints include ORR, lymph node response rate, CR rate, and OS. This is an event-driven trial and primary endpoint evaluation will be based on independent central review. For the primary efficacy analysis, the difference in PFS between the treatment arms will be assessed in the ITT analysis set. The study was initiated in June 2012 and a data monitoring committee has begun regular review of data. Clinical trial information: NCT01569295.

Tolerability and activity of combinations of the PI3Kδ inhibitor idelalisib (GS-1101) with rituximab and/or bendamustine in patients with previously treated, indolent non-Hodgkin lymphoma (iNHL): Updated results from a phase I study

8500

Background: PI3K-delta signaling is critical for activation, proliferation and survival of B cells, and is hyperactive in many B-cell malignancies. Idelalisib is a first-in-class, selective, oral inhibitor of PI3Kδ that has shown considerable monotherapy activity in recurrent iNHL (Kahl, ICML 2011), as well as combination therapy (Fowler, ASCO 2012). Methods: This phase I study evaluated the activity of continuous (48 weeks) idelalisib (Id), 100/150 mg BID, in combination with rituximab (R) (375 mg/m2 weekly x 8 doses) (Id+R), with bendamustine (B) (90 mg/m2 x 2, for 6 cycles) (Id+B), or in combination with R (375 mg/m2 monthly x 6) and B (90 mg/m2 x 2), for 6 cycles (Id+BR). Investigators assessed response according to standard criteria (Cheson 2007). Patients who continued to benefit were able to enroll on an extension study. Results: Study enrolled 78 pts with relapsed/refractory iNHL, with 34 (44%) pts continuing on treatment in the ongoing extension protocol. The 3 cohorts included Id+R (N=30), Id+B (N=34), and Id+BR (N=14). Pts were 67% male, median age [range] of 62 [37E84] years, 41% with refractory disease, 88% stage III/IV, and 36% of FL with high FLIPI scores. The median [range] number of prior therapies was 3 [1E10]. The median [range] duration of treatment was 10.6 [0.5-29.2] months. Overall response rate (ORR) was 63/78 (81%), with 22/78 (28%) CR. The ORR/CR for Id+R was 77%/20%, Id+B was 85%/29%, and Id+BR was 79%/43%. At 20 months, the PFS was 66%. For responders, 73% were progression-free at 20 months. Most common adverse events included (total%/≥G3%) pyrexia (56/4), fatigue (45/4), nausea (41/0), rash (40/8), cough (37/0), diarrhea (36/8), chills (18/0), URI (18/1), and pneumonia (17/15). Lab abnormalities included (total%/≥G3%) ALT/AST elevations (56/17). Conclusions: Idelalisib-based combination therapy is highly active and well tolerated in patients with relapsed/refractory iNHL. These data support further clinical development. Phase III trials evaluating the efficacy of idelalisib in combination with R, or BR in iNHL are ongoing (NCT01732913, NCT01732926). Clinical trial information: NCT01732913, NCT01732929.

Update on a phase I study of the selective PI3Kδ inhibitor idelalisib (GS-1101) in combination with rituximab and/or bendamustine in patients with relapsed or refractory CLL

7017

Background: PI3K-delta signaling is critical for proliferation, survival, homing and tissue retention of malignant B cells. Idelalisib is a first-in-class, selective, oral inhibitor of PI3Kδ that has shown considerable monotherapy activity in pts with heavily pretreated CLL. Methods: This phase I study evaluated idelalisib continuously given at 150 mg BID in combination with rituximab (R, 375 mg/m2 every wk x 8), bendamustine (B, 70 or 90 mg/m2 x 2, every 4 wks x 6) or BR (every 4 wks x 6) for relapsed/refractory CLL. Pts still on treatment after 48 weeks were eligible to continue idelalisib on an extension study. Clinical response was evaluated according to published criteria (Hallek 2008; Cheson 2012). Results: 52 pts (23F/29M) with a median (range) age of 64 (41-87) years were enrolled. Adverse disease characteristics included bulky lymphadenopathy (62%), refractory disease (50%), multiple prior therapies (median 3, range: 1-14) with 96% receiving prior R and 44% receiving prior B. As of 14 Jan 2013, the median (range) treatment duration was 18 (1-33) months. 31/52 (60%) pts enrolled into the extension study; of those, 24/52 (46%) pts are continuing idelalisib treatment on the extension study. The ORR was 81%, with 1 CR, and a median (range) time to response of 1.9 (1.5-8.3) months. The 2-year PFS and OS were 62% and 85%, respectively. At 2 years follow up, 71% of responses were still enduring. There was no difference in outcomes for pts with <3 prior treatments (n=21) vs ≥3 prior treatments (n=31). The most common TEAEs (any Grade/≥Gr 3, independent of causality) included pyrexia (44%/6%), diarrhea (40%/14%), cough (31%/2%), fatigue (29%/2%), nausea (29%/0%). Pneumonia (any Gr/≥Gr 3) occurred in 15%/12% and rash was seen in 15%/0%. 10% of patients experienced ≥Gr 3 ALT/AST elevation based on laboratory values. Conclusions: A lack of overlapping toxicities allowed idelalisib to be co-administered with R, B, or BR, and all 3 combination regimens were highly active, resulting in durable tumor control in pts with heavily pretreated relapsed/refractory CLL. Phase III trials evaluating the efficacy of idelalisib in combination with R or BR are ongoing. Clinical trial information: NCT01088048.

Study of medically important Vibrios in the sewage of Katmandu Valley, Nepal

A total of 42 samples were collected from the different sites of sewer system of Kathmandu Valley during rainy summer season (June to September 2008) using Moore's technique. Samples (on Moore's swabs) were submersed in alkaline peptone water (pH 8.6) and transported to Research Laboratory of National Institute of Tropical Medicine and Public Health Research, Kathmandu in cold condition (ice chest) followed by incubation at 37 degrees C for 8 hours. After incubation, culture was done on thiosulfate-citrate-bile salt-sucrose (TCBS) agar and incubated at 37 degrees C for overnight (15 hrs). Both yellow and green colonies measuring from 2 to 9 mm in diameter on TCBS agar were subjected for gram staining, biochemical testing as well as sero-typing using antisera (poly O1, Ogawa and Inaba) (Denka Seiken Co. Ltd, Japan). Altogether 46 medically important Vibrios were isolated from 42 samples studied. The isolates were identified as V. cholerae (n = 20; 43.5%), V. vulnificus (n = 11; 23.9%), V. parahaemolyticus (n = 5; 10.9%), V. furnissi (n = 5; 10.9%), V. fluvialis (n = 3; 6.5%) and V. alginolyticus (n = 2; 4.3%). Of the 20 V. cholerae isolates, 13 (65.0%) and 7 (35.0%) isolates were V. cholerae O1 and non-O1, respectively. Among the V. cholerae O1 (n = 13), classical Hikojima strain was most frequently isolated (n = 10) followed by V. cholerae O1 Ogawa (El Tor = 2 and classical = 1). High frequency of V. cholerae isolation from sewer system of Kathmandu Valley is an indication of possible outbreak of cholera anytime in future and, therefore, demands improvement in sanitary condition, supply/consumption of safe drinking water and personal hygiene.

Study of parasitic infection among children of Sukumbasi Basti in Kathmandu valley

Keeping in view of heavy burden of intestinal parasitosis, present study was done to find out the prevalence of intestinal parasitic infection in children (aged <16 years) of Sukumbasi (people living without land ownership) Basti (community) in Kathmandu Valley. A total of 279 stool samples collected in clean, dry and screw capped plastic container were firstly examined for the presence of adult worm and/or segments of worms. Samples fixed in 10% formal-saline were then examined microscopically after concentration by formal-ether sedimentation technique. Overall parasite positive rate was 43.3% (121/279) with no significant difference in two genders (Boys: 48.3%, 73/151; Girls: 37.5%, 48/128) (p=0.07). Altogether 11 species of parasites were detected. Of them Giardia lamblia was most common followed by Entamoeba histolytica, Trichuris trichiura and others. Positive rate was higher in Tibeto-Burman (55.0%, 77/140) and the least in Indo-Aryan (25.4%, 27/ 106) (p=0.01) ethnic groups. Children taking anti-parasitic drug in last six months had significantly low positive rate (25.4%, 15/59) than others (48.2%, 106/220) (p=0.002). Results of this study suggestive of periodic administration of anti-parastic drugs and need for improvement of sanitary/hygienic practice.

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/m(2) i.v. on day 1 (D-1). Cyclophosphamide was given at a dose of 750 mg/m(2) 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.

Alemtuzumab in previously treated chronic lymphocytic leukemia patients who also had received fludarabine

PURPOSE

This phase II pilot study determined the efficacy and safety of alemtuzumab (Campath-1H; Burroughs Wellcome, United Kingdom) in patients with chronic lymphocytic leukemia (CLL), all of whom had previously received fludarabine and other chemotherapy regimens.

PATIENTS AND METHODS

Twenty-four patients were treated with intravenous alemtuzumab at six centers in the United States. The target dose of 30 mg over 2 hours, three times weekly, was administered for up to 16 weeks. Responses were evaluated by an independent panel of experts using 1996 National Cancer Institute-sponsored Working Group criteria. Safety assessments included analysis of lymphocyte subpopulations. Antimicrobial prophylaxis was not mandatory.

RESULTS

Eight patients (33%) achieved a major response (all partial remissions), with a median time to response of 3.9 months (range, 1.6 to 5.3 months). The median duration of response was 15.4 months (range, 4.6 to >or= 38.0 months), the median time to disease progression was 19.6 months (range, 7.7 to >or= 42.0 months), and the median survival time was 35.8 months (range, 8.8 to >or= 47.1 months). Acute infusion-related events, mainly grades 1 and 2, were most common and most severe in the first week. Ten patients (eight nonresponders and two responders) experienced major infections on-study. Pneumocystis carinii pneumonia was reported in two patients on-study; neither had received prophylaxis. Median CD4+ and CD8+ counts decreased and then began to increase by the end of the study, with further recovery by 1-month follow-up. One of 53 samples obtained from 10 patients had a low titer of alemtuzumab antibodies.

CONCLUSION

Alemtuzumab has significant activity in poor-prognosis, fludarabine-treated CLL patients. However, because of a relatively high incidence of opportunistic infections accompanying profound lymphopenia, future protocols should include mandatory prophylaxis.

Chronic lymphocytic leukemia: case-based session

Drs. Hartmut Döhner, Michael J. Keating, Kanti R. Rai and Emili Montserrat form the panel to review chronic lymphocytic leukemia (CLL) while focusing on the clinical features of a particular patient. The pace of progress in CLL has accelerated in the past decade. The pathophysiological nature of this disease, as had been known in the past, was based largely on the intuitive and empiric notions of two leaders in hematology, William Dameshek and David Galton. Now the works of a new generation of leaders are providing us with the scientific explanations of why CLL is a heterogeneous disease, perhaps consisting of at least two separate entities. In one form of CLL, the leukemic lymphocytes have a surface immunoglobulin (Ig) variable region gene that has undergone somatic mutations, with tell-tale markers suggesting that these cells had previously traversed the germinal centers. Such patients have a distinctly superior prognosis than their counterparts whose leukemic lymphocytes IgV genes have no mutations (these are indeed immunologically naive cells), who have a worse prognosis. The introduction of fluorescence in situ hybridization (FISH) technique has provided us with new insights into the diverse chromosomal abnormalities that can occur in CLL, and which have significant impact on the clinical behavior and prognosis of patients with this disease. Major advances in therapeutics of CLL also have occurred during the past decade. Two monoclonal antibodies, Campath-1H (anti-CD52) and rituximab (anti-CD20), and one nucleoside analogue, fludarabine, have emerged as three agents of most promise in the front-line treatment of this disease. Studies currently in progress reflect our attempts to find the most effective manner of combining these agents to improve the overall survival statistics for CLL patients. As in many other hematological malignancies, high dose chemotherapy followed by autologous or HLA-compatible allogeneic stem cells rescue strategies are under study as a salvage treatment for a relatively younger age group of CLL patients with poor prognosis characteristics.

Impact of therapy With chlorambucil, fludarabine, or fludarabine plus chlorambucil on infections in patients with chronic lymphocytic leukemia: Intergroup Study Cancer and Leukemia Group B 9011

PURPOSE

We sought to determine whether therapy with single-agent fludarabine compared with chlorambucil alone or the combination of both agents had an impact on the incidence and spectrum of infections among a series of previously untreated patients with B-cell chronic lymphocytic leukemia (CLL).

PATIENTS AND METHODS

Five hundred fifty-four previously untreated CLL patients with intermediate/high-risk Rai-stage disease were enrolled onto an intergroup protocol. Patients were randomized to therapy with chlorambucil, fludarabine, or fludarabine plus chlorambucil. Data pertaining to infection were available on 518 patients. Differences in infections among treatment arms were tested with the Kruskal-Wallis, Wilcoxon, and chi(2) tests.

RESULTS

A total of 1,107 infections (241 major infections) occurred in 518 patients over the infection follow-up period (interval from study entry until either reinstitution of initial therapy, therapy with a second agent, or death). Patients treated with fludarabine plus chlorambucil had more infections than those receiving either single agent (P <.0001). Comparing the two single-agent arms, there were more infections on the fludarabine arm (P =.055) per month of follow-up. Fludarabine therapy was associated with more major infections and more herpesvirus infections compared with chlorambucil (P =.008 and P =.004, respectively). Rai stage and best response to therapy were not associated with infection. A low serum immunoglobulin G was associated with number of infections (P =.02). Age was associated with incidence of major infection in the combination arm (P =.004).

CONCLUSION

Combination therapy with fludarabine plus chlorambucil resulted in significantly more infections than treatment with either single agent. Patients receiving single-agent fludarabine had more major infections and herpesvirus infections compared with chlorambucil-treated patients.

Fludarabine compared with chlorambucil as primary therapy for chronic lymphocytic leukemia

BACKGROUND

Fludarabine is an effective treatment for chronic lymphocytic leukemia that does not respond to initial treatment with chlorambucil. We compared the efficacy of fludarabine with that of chlorambucil in the primary treatment of chronic lymphocytic leukemia.

METHODS

Between 1990 and 1994, we randomly assigned 509 previously untreated patients with chronic lymphocytic leukemia to one of the following treatments: fludarabine (25 mg per square meter of body-surface area, administered intravenously daily for 5 days every 28 days), chlorambucil (40 mg per square meter, given orally every 28 days), or fludarabine (20 mg per square meter per day for 5 days every 28 days) plus chlorambucil (20 mg per square meter every 28 days). Patients with an additional response at each monthly evaluation continued to receive the assigned treatment for a maximum of 12 cycles.

RESULTS

Assignment of patients to the fludarabine-plus-chlorambucil group was stopped when a planned interim analysis revealed excessive toxicity and a response rate that was not better than the rate with fludarabine alone. Among the other two groups, the response rate was significantly higher for fludarabine alone than for chlorambucil alone. Among 170 patients treated with fludarabine, 20 percent had a complete remission, and 43 percent had a partial remission. The corresponding values for 181 patients treated with chlorambucil were 4 percent and 33 percent (P< 0.001 for both comparisons). The median duration of remission and the median progression-free survival in the fludarabine group were 25 months and 20 months, respectively, whereas both values were 14 months in the chlorambucil group (P<0.001 for both comparisons). The median overall survival among patients treated with fludarabine was 66 months, which was not significantly different from the overall survival in the other two groups (56 months with chlorambucil and 55 months with combined treatment). Severe infections and neutropenia were more frequent with fludarabine than with chlorambucil (P=0.08), although, overall, toxic effects were tolerable with the two single-drug regimens.

CONCLUSIONS

When used as the initial treatment for chronic lymphocytic leukemia, fludarabine yields higher response rates and a longer duration of remission and progression-free survival than chlorambucil.

Future strategies toward the cure of indolent B-cell malignancies. New biologic therapies

Although chronic lymphocytic leukemia (CLL) cells provide an excellent target for antibody therapy, to date this approach has met with limited success in patients with CLL. Promising data are emerging with a new generation of antibodies, such as Campath-1H, which may offer effective therapeutic options not only as single agents but also in combination with such drugs as fludarabine. Other new antibodies, including rituximab and several new radioimmunoconjugates, have provided impressive results in the indolent non-Hodgkin's lymphomas and warrant further investigation.

Ig V gene mutation status and CD38 expression as novel prognostic indicators in chronic lymphocytic leukemia

Cellular immunophenotypic studies were performed on a cohort of randomly selected IgM(+) B-chronic lymphocytic leukemia (B-CLL) cases for which Ig V(H) and V(L) gene sequences were available. The cases were categorized based on V gene mutation status and CD38 expression and analyzed for treatment history and survival. The B-CLL cases could be divided into 2 groups. Those patients with unmutated V genes displayed higher percentages of CD38(+) B-CLL cells (>/=30%) than those with mutated V genes that had lower percentages of CD38(+) cells (<30%). Patients in both the unmutated and the >/=30% CD38(+) groups responded poorly to continuous multiregimen chemotherapy (including fludarabine) and had shorter survival. In contrast, the mutated and the <30% CD38(+) groups required minimal or no chemotherapy and had prolonged survival. These observations were true also for those patients who stratified to the Rai intermediate risk category. In the mutated and the <30% CD38(+) groups, males and females were virtually equally distributed, whereas in the unmutated and the >/=30% CD38(+) groups, a marked male predominance was found. Thus, Ig V gene mutation status and the percentages of CD38(+) B-CLL cells appear to be accurate predictors of clinical outcome in B-CLL patients. These parameters, especially CD38 expression that can be analyzed conveniently in most clinical laboratories, should be valuable adjuncts to the present staging systems for predicting the clinical course in individual B-CLL cases. Future evaluations of new therapeutic strategies and drugs should take into account the different natural histories of patients categorized in these manners.

Delphi-panel analysis of appropriateness of high-dose therapy and bone marrow transplants in chronic myelogenous leukemia in chronic phase

BACKGROUND

It is uncertain which people with chronic myelogenous leukemia (CML) in chronic phase should receive conventional treatment (interferon and/or chemotherapy) versus high-dose therapy and a bone marrow transplant. There are no randomized trials comparing these approaches and analyses of data from non-randomized studies are complex, contradictory without sufficient detail to allow subject-level treatment decisions.

OBJECTIVE

Determine appropriateness of high-dose therapy and bone marrow transplants in persons with CML in chronic phase with specific features. Develop a treatment algorithm. PANELISTS: nine leukemia experts from diverse geographic sites and practice settings.

EVIDENCE

Boolean MEDLINE searches of chronic myelogenous leukemia and chemotherapy and/or transplants.

CONSENSUS PROCESS

We used a modified Delphi-panel group judgment process. Age, prognostic score, disease duration, and type of conventional therapy and response were permuted to define 90 clinical settings. Each panelist rated appropriateness of high-dose therapy and a transplant versus conventional therapy on a 9-point ordinal scale (1, most inappropriate, 9, most appropriate) considering three types of donors: (1) HLA-identical siblings; (2) alternative donors (HLA-matched related or unrelated people other than an HLA-identical sibling); and (3) autotransplants. An appropriateness index was developed based on median rating and amount of disagreement. Relationship of appropriateness indices to permuted clinical variables was considered by analysis of variance and recursive partitioning. Preference between donor types was analyzed by comparing mean appropriateness indices of similar settings and a treatment algorithm developed.

CONCLUSIONS

In people with CML in chronic phase and an HLA-identical sibling donor and in those with an alternative donor (but no HLA-identical sibling), a transplant was rated appropriate in those with a < or = partial cytogenetic response to interferon and uncertain or inappropriate in all other settings. Autotransplants were rated uncertain or inappropriate in all settings. Most of the variance in appropriateness ratings between different clinical settings was accounted for by response to interferon: complete versus < or = partial response. An HLA-identical sibling donor, when available, was always preferred to an alternative donor or autotransplant. In people without an HLA-identical sibling, an alternative donor was favored over an autotransplant at higher appropriateness indices and the converse at lower appropriateness indices.

Delphi-panel analysis of appropriateness of high-dose therapy and bone marrow transplants in adults with acute myelogenous leukemia in 1st remission

BACKGROUND

Despite considerable data, there is still controversy over which adults with acute myelogenous leukemia (AML) in 1st remission should receive high-dose therapy and a bone marrow transplant rather than conventional-dose chemotherapy. Analyses of data from randomized trials are complex, conclusions sometimes contradictory and results not sufficiently detailed to allow subject-level decisions.

OBJECTIVE

To determine appropriate use of high-dose therapy and bone marrow transplants in persons with AML in 1st remission with specific features. Develop a treatment algorithm. PANELISTS: Nine leukemia experts from diverse geographic sites and practice settings.

EVIDENCE

Boolean MEDLINE searches of acute myelogenous leukemia and chemotherapy and/or transplants.

CONSENSUS PROCESS

We used a modified Delphi-panel group judgment process. Age, WBC, cytogenetics and FAB-type were permuted to define 72 clinical settings. Each panelist rated appropriateness of high-dose therapy and a transplant versus conventional-dose chemotherapy on a nine-point ordinal scale (1, most inappropriate, 9, most appropriate) considering 3 types of donors: (1) HLA-identical siblings; (2) alternative donors (HLA-matched related or unrelated people other than an HLA-identical sibling); and (3) autotransplants. An appropriateness index was developed based on median rating and amount of disagreement. The relationship of appropriateness indices to the permuted clinical variables was considered by analysis of variance and recursive partitioning. Preference between donor types was analyzed by comparing mean appropriateness indices of comparable settings and a treatment algorithm developed.

CONCLUSIONS

In people with an HLA-identical sibling, this type of transplant was rated appropriate in those with unfavorable cytogenetics and uncertain in all other settings. In people without an HLA-identical sibling, an alternative donor transplant was rated appropriate in those < 30 years with unfavorable cytogenetics, uncertain in those > 30 years and unfavorable cytogenetics and inappropriate in all other settings. Autotransplants were rated appropriate in people with unfavorable cytogenetics and uncertain in all other settings. An HLA-identical sibling donor, when available, was always preferred to an alternative donor transplant or autotransplant. In people without an HLA-identical sibling, an autotransplant was almost always favored over an alternative donor transplant with the magnitude of preference inversely correlated with transplant appropriateness.

Delphi-panel analysis of appropriateness of high-dose therapy and bone marrow transplants in adults with acute lymphoblastic leukemia in first remission

BACKGROUND

There is controversy over whether high-dose therapy and a bone marrow transplant is better than conventional-dose chemotherapy in adults with acute lymphoblastic leukemia (ALL) in first remission. This decision may depend on which type of donor is available: an HLA-identical sibling, an alternative donor transplant (HLA-matched related or unrelated people other than HLA-identical siblings), or autotransplant.

OBJECTIVE

To determine the appropriate use of high-dose therapy and bone marrow transplants in ALL in first remission. Develop a treatment algorithm. PANELISTS: Nine leukemia experts from diverse geographic sites and practice settings.

EVIDENCE

Boolean MEDLINE searches of acute lymphoblastic leukemia and chemotherapy and/or transplants.

CONSENSUS PROCESS

We used a modified Delphi-panel group judgment process. Age, white blood cell (WBC) count, cytogenetics and immune type were permuted to define 48 clinical settings. Each panelist rated appropriateness of high-dose therapy and a transplant versus conventional-dose chemotherapy on a 9-point ordinal scale (1, most inappropriate; 9, most appropriate) considering three types of donors: (1) HLA-identical siblings; (2) alternative donors; and (3) autotransplants. An appropriateness index was developed based on median rating and amount of disagreement. Relationship of appropriateness indices to the permuted clinical variables was considered by analysis of variance and recursive partitioning. Preference between donor types was analyzed by comparing mean appropriateness indices of comparable settings and a treatment algorithm was developed.

CONCLUSIONS

In people with an HLA-identical sibling donor, transplants were rated appropriate in those with unfavorable cytogenetics and uncertain in all other settings. An HLA-identical sibling donor was always preferred to an alternative donor or autotransplant. In people without an HLA-identical sibling but with an alternative donor, this type of transplant was rated appropriate in those with unfavorable cytogenetics. However, an autotransplant was preferred over an alternative donor transplant in all other settings where a transplant was rated uncertain. In people without an HLA-identical sibling or alternative donor, autotransplants were rated uncertain in all settings except in those with not unfavorable cytogenetics, WBC < 100 x 10(9) l(-1) and T- or pre-B-cell type where they were rated inappropriate.

Cladribine for the treatment of hairy cell leukemia and chronic lymphocytic leukemia

Cladribine (Leustatin; Janssen-Cilag, Ortho Biotech Inc, Raritan, NJ) is a novel injectable nucleoside analogue with marked efficacy against hairy cell leukemia and considerable, although less dramatic, activity against chronic lymphocytic leukemia and non-Hodgkin's lymphoma. The effect is thought to be due to the drug's ability, after intracellular phosphorylation, to inhibit repair of single-strand DNA breaks in certain malignant lymphocyte and monocyte subtypes. We treated 49 patients with active hairy cell leukemia with continuous infusion of cladribine at a dose of 0.1 mg/kg/ d for 7 days. A single course of therapy gave a complete response rate of 76% and a partial response rate of 24%; the effect was durable for several years in most cases. We also treated 14 patients with chronic lymphocytic leukemia with cladribine and obtained an overall response rate of 43%; this required several courses of monthly treatment. These responses tended to be short-lived and did not substantially change life expectancy of chronic lymphocytic leukemia patients. In both diseases, myelosuppression and immunosuppression, sometimes resulting in neutropenic fever, were the only toxicities associated with cladribine.

Old and new therapies in chronic lymphocytic leukemia: now is the time for a reassessment of therapeutic goals

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia for which therapeutic options remain unsatisfying as cure has remained elusive. Recent laboratory discoveries and promising results from completed phase III studies with fludarabine provide reason to reassess therapeutic goals in the treatment of patients with symptomatic CLL. Early enrollment of patients on protocols using combination therapies with fludarabine and new agents such as flavopiridol, IDEC-C2B8, Campath-1H, UCN-01, bryostatin, FR 901228, and melarsoprol will hopefully represent the next advance to improved overall survival and ultimately the cure of CLL.

Chronic lymphocytic leukemia in the elderly population

Chronic lymphocytic leukemia (CLL) is a disease of the elderly with an incidence of about 20 to 30 per 100,000 population in the group aged 70 years or older. Chemotherapy with chlorambucil controls major clinical features of CLL but without prolongation of survival time. Addition of prednisone is necessary when autoimmune complications occur, but its usage in the elderly requires special caution. Fludarabine has better response rates than chlorambucil in treating CLL and has been proved to be an effective salvage therapy in patients previously treated with chlorambucil.

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.

Supportive telephone intervention for patients receiving chemotherapy. A pilot study

Psychosocial interventions have been shown to improve quality of life (QOL) for many cancer patients. A pilot study was conducted to assess the feasibility of a psychoeducational intervention for cancer patients receiving chemotherapy. Eight patients receiving chemotherapy for colorectal carcinoma participated. The intervention is based on a modification of Interpersonal Therapy. It consisted of four sessions, administered biweekly, using a manual format, by a psychiatric nurse clinician over the telephone. The participants also completed a set of QOL measures by telephone to assess tolerance of the planned assessment. The patients received assistance with treatment-related side effects, reported improved ability to communicate with their physician, and gained an understanding of the stresses they discussed. The patients felt satisfied with the emotional support and medical information provided. A randomized trial is planned to test the intervention for patients participating in a cooperative trial sponsored by the National Cancer Institute.

The induction of p53 and WAF1/CIP1 in chronic lymphocytic leukemia cells treated with 2-chlorodeoxyadenosine

The treatment of chronic lymphocytic leukemia includes the use of alkylating agents, steroids, and more recently nucleoside analogues. While prior studies have described potential mechanisms of 2-chlorodeoxyadenosine cytotoxicity including the accumulation of DNA strand breaks and induction of apoptosis or programmed cell death, the expression of p53 and its downstream target WAF1/CIP1 have not been examined. In this report we describe the induction of p53 and WAF1/CIP1 in the apoptotic chronic lymphocytic leukemia cells after exposure to 2-chlorodeoxyadenosine.

Recombinant alpha-2b-interferon in therapy of previously untreated hairy cell leukemia: long-term follow-up results of study by Cancer and Leukemia Group B

In 1985, Cancer and Leukemia Group B initiated a multi-institutional study to define the role of interferon alpha in therapy of previously untreated active hairy cell leukemia (HCL). This is a long-term follow-up report of the study. Fifty-five evaluable patients were treated with recombinant interferon-2b 2 million units/m2 subcutaneously three times a week for 1 year. Treatment was well tolerated; toxicity mainly consisted of flu-like syndrome and pancytopenia, both of a transient nature. Seventy-three percent of patients had objective beneficial responses with 8.3 months median time to achieve at least a partial response (PR). After 1 year of therapy, the patients have been observed for a median of 5 years. There was a continual trend towards relapse throughout this period but 28% have remained in remission beyond 6 years. Forty-six patients (83%) are alive at 6 years. Among the 40 patients who achieved at least a PR, there were 28 with splenomegaly at the beginning of study: the spleen size was reduced in all with interferon alpha therapy and none required splenectomy. This study confirms the results of other investigators, and demonstrates that recombinant alpha interferon-2b is an effective agent for treatment of hairy cell leukemia.

Impaired interferon alpha response in hairy cell leukemia is corrected by therapy with 2-chloro-2'-deoxyadenosine: implications for susceptibility to opportunistic infections

Patients with hairy cell leukemia (HCL) are susceptible to opportunistic intracellular infections, suggesting defects in cellular immunity. Prior studies have indicated an association between failure of IFN-alpha generation by peripheral blood mononuclear cells (MNC) and susceptibility to such infections. We here present results on IFN-alpha generation in HCL patients pre- and post-therapy. Prior to treatment with 2-chloro-2'-deoxyadenosine (CdA), MNC from 24 HCL patients with active disease produced little or not IFN-alpha (geometric mean < 40 IU/ml) compared with controls (n = 140, geometric mean 1730 IU/ml, p < 0.0005). After treatment with CdA, IFN-alpha generation was studied in 16 patients, with a geometric mean value of 650 IU/ml (p < 0.0005 compared with pre-CdA levels). The severe depression of IFN-alpha generation improved progressively following CdA therapy-induced clinical remission. We propose that deficiency of IFN-alpha production may play a role in the susceptibility to intracellular infections of patients with active HCL.

Progress in chronic lymphocytic leukaemia: a historical perspective

A historical review of gains in the body of knowledge on chronic lymphocytic leukaemia (CLL) reveals a continuous, steady process from the beginning of the century with the pioneering work of scholars to the present era of molecular biology. Several notable hallmarks of this progress have been recognized: (1) the early period of broad, loose grouping of all chronic lymphoproliferative disorders; (2) recognition of CLL as a discrete entity with clinical and cytological identification of different forms of lymphoid neoplasm; (3) development of clinical staging systems and prognostic factors; and (4) use of immunological techniques in the study of CLL. Studies currently in progress using molecular genetic techniques hold promise for future advances in unravelling the biology of leukaemic transformation of lymphocytes in CLL.

5th International Workshop on Chronic Lymphocytic Leukemia

In the past few years important advances have been made in our understanding of the biology and natural history of CLL; also, new strategies and agents offer promise in the treatment of this form of leukemia. Now, patients can be treated on a more rationale basis and with real prospects for a sustained control of their disease, and improved quality of life. Hopefully, progresses in CLL will continue to accumulate in the coming years.

Distinct characteristics of lymphokine-activated killer (LAK) cells derived from patients with B-cell chronic lymphocytic leukemia (B-CLL). A factor in B-CLL serum promotes natural killer cell-like LAK cell growth

We show that lymphokine-activated killer (LAK) cell precursors derived from patients with B-cell chronic lymphocytic leukemia (B-CLL) and cultured in the presence of recombinant interleukin-2 and normal human serum (NHS), develop into primarily NK cell-like (CD 57+) LAK cells, whereas identically prepared LAK cell precursors from normal subjects develop into mainly T cell-like (CD 3+, CD 8+) LAK cells. B-CLL LAK cells exhibited greater proliferative capacity than did normal LAK cells. When normal LAK cells were grown in B-CLL serum instead of NHS, their proliferation increased; NK cell levels also increased to those found in B-CLL LAK cells, suggesting that B-CLL serum contains a factor that promotes NK cell-like growth, LAK cells derived from normal or B-CLL patients demonstrated similar lytic activity toward K562 and Raji cells. Growth in B-CLL serum did not reduce their lytic potential. Thus, the altered phenotype and growth exhibited by B-CLL LAK cells and normal LAK cells grown in B-CLL serum does not lead to abnormalities in their cytolytic functions. We propose instead that the predominance of NK-like cells in B-CLL LAK cell populations and the presence of an NK cell-like growth factor in B-CLL serum reflect abnormalities related to NK cell-mediated B-cell regulation; ie, either inhibition of normal B-cell growth and/or growth stimulation of the leukemic clone in B-CLL.

Chronic lymphocytic leukemia: new insights into biology and therapy

PURPOSE

To review the recent advances in the biologic and clinical research of chronic lymphocytic leukemia.

DATA IDENTIFICATION

English-language literature search using MEDLINE (1980 to 1990) and CANCERLIT (1980 to 1990), review of meeting abstracts and reports, and an extensive manual search of bibliographies of identified articles.

STUDY SELECTION

Approximately 800 articles, abstracts, and book chapters were selected for analysis.

DATA EXTRACTION

The literature was reviewed and 227 articles were selected as representative of the important advances in chronic lymphocytic leukemia.

RESULTS OF DATA SYNTHESIS

Chronic lymphocytic leukemia is a disease of lymphocytes that appear to be mature but are biologically immature. These B lymphocytes arise from a subset of CD5-B cells that appear to have a role in autoimmunity. The pathogenesis of chronic lymphocytic leukemia is likely a multistep process, initially involving a polyclonal expansion of CD5-B cells followed by transformation of a single cell. Chromosome studies indicate that trisomy 12 is the most common abnormality, followed by 14q+, 13q, and 11q. These abnormalities portend a poor prognosis. Recent progress in the treatment of chronic lymphocytic leukemia involves three new drugs: fludarabine, pentostatin, and 2-chlorodeoxyadenosine. Recent preliminary results of allogeneic bone marrow transplantation present insights into the potential curability of chronic lymphocytic leukemia. Therapy with intravenous immunoglobulin can prevent or delay moderate bacterial infections in persons with chronic lymphocytic leukemia.

CONCLUSION

Major advances in the biologic research of chronic lymphocytic leukemia have resulted in new understanding of this complex disease. New therapies, such as those with intravenous immunoglobulin and fludarabine, may lead to improved outcome.

Characteristics of CD11c+CD5+ chronic B-cell leukemias and the identification of novel peripheral blood B-cell subsets with chronic lymphoid leukemia immunophenotypes

Previous studies have indicated that chronic lymphocytic leukemias (CLL) are characterized by the coexpression of CD5 and B-cell antigens, while hairy cell leukemias (HCL) typically express CD11c+CD5- B-cell immunophenotypes. In this report we describe the features of B-cell leukemias with CD11c+CD5+ immunophenotypes and the identification of novel circulating B-cell subsets defined by the expression of CD20, CD5, and CD11c antigens. Morphologic evaluation of 14CD11c+CD5+ B-cell leukemias showed that they generally had larger cellular diameters (14 to 21 microns) and lower nuclear:cytoplasm ratios than typical small lymphocyte CLL. These cases did not exhibit the well-defined nucleoli characteristic of prolymphocytic leukemia (PLL). The presenting clinical features of CD11c+CD5+ B-cell leukemias were most consistent with CLL or PLL, and none of the evaluated cases had pancytopenia, splenomegaly, and cytoplasmic villi characteristic of HCL. Examination of normal peripheral blood (n = 6) by three-color flow cytometry identified four novel B-cell subsets with the following immunophenotypes (mean percent of total CD20+ B cells +/- SE): CD20+CD5+CD11c+ (8.0 +/- 1.6); CD20+CD5-CD11c+ (12.0 +/- 2.0); CD20+CD5+CD11c- (35.0 +/- 4.9); and CD20+CD5-CD11c- (44.0 +/- 5.0). Our findings suggest that CD11c+CD5+ B-cell leukemias with atypical morphologic features represent forms of CLL or PLL rather than HCL. In addition, we have identified novel subsets of circulating B cells defined by patterns of CD20, CD5, and CD11c expression that correspond to the immunophenotypes of chronic B-cell leukemias.

Prognostic factors and clinical staging in chronic lymphocytic leukemia

There has been significant progress in the past 10 years in our ability to prospectively predict prognosis in CLL. The clinical staging systems have helped us identify three broad groups of patients with respect to their overall outlook for survival: low risk (stage 0), intermediate risk (stages I and II), and high risk (stages III and IV). It seems reasonable to distinguish those low- and intermediate-risk patients who are likely to have a benign or indolent clinical course if their blood lymphocyte doubling time is longer than 12 months and their bone marrow biopsy pattern of lymphocytic infiltration is nondiffuse. With these guidelines, it will be possible to initiate meaningful and reliable therapeutic trials in CLL in the immediate future.

Management of chronic lymphocytic leukemia

Significant progress has been made in the past two decades in the understanding of immunobiology of CLL and the development of clinical staging systems and identification of other prognostic factors in CLL. A significant advance in the management of CLL has also been made. Now we know when to initiate therapy. We recommend that patients with stage 0 and patients with stages I and II associated with good prognostic features such as absence of disease-related symptoms, long lymphocyte doubling time, nondiffuse bone marrow infiltration, and low tumor load not be treated; they should be followed at 2- to 6-month intervals. We recommend initiation of therapy for patients with stages I and II, associated with poor prognostic features such as presence of disease-related symptoms, short lymphocyte doubling time, diffuse bone marrow infiltration, and high tumor load and for patients with stages III and IV. However, we still do not know what constitutes the optimal therapy for the disease. In one large randomized study, the response rate as well as survival superiority of CHOP (with low-dose Adriamycin) over COP in previously untreated patients with stage C disease was observed. In another large randomized study, only a response rate advantage of CHOP (with standard dose Adriamycin) over chlorambucil and prednisone (in previously untreated patients with stages B and C) was seen. No randomized studies have compared CHOP versus chlorambucil and prednisone in patients with stages III and IV or stage C. At present, our recommendation for the treatment of patients with advanced disease is chlorambucil and prednisone therapy. New drugs under clinical trials for CLL include (1) deoxycoformycin, (2) 2-chlorodeoxyadenosine, and (3) fludarabine monophosphate. Both deoxycoformycin and 2-chlorodeoxyadenosine have been shown to have some activity in previously treated CLL patients with advanced disease. The effectiveness of these agents, however, has not been tested yet in untreated patients with advanced disease. Fludarabine monophosphate, on the other hand, has been shown to be very effective in both previously treated and untreated patients with advanced disease. Allogeneic bone marrow transplantation recently has been found to be of benefit in some patients (37 to 46 years) in a preliminary study; this therapeutic procedure should be tested further in a larger population of younger patients (less than 50 years) with advanced CLL. New agents such as lymphokines (interferons and IL-2) and monoclonal antibodies have been investigated for their efficacy and found to be minimally effective in previously treated patients with advanced disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Guidelines for clinical protocols for chronic lymphocytic leukemia: recommendations of the National Cancer Institute-sponsored working group

The National Cancer Institute (NCI)-sponsored Chronic Lymphocytic Leukemia (CLL) Working Group was convened to develop a set of standardized eligibility, response, and toxicity criteria for clinical trials. We recognized the previous efforts in 1967 (published again in 1973 as the report of the Chronic Leukemia-Myeloma Task Force [1] and 1978 of Cancer and Leukemia Group B (CALGB) [2]). We have used these reports for guidance during the current effort. Several noteworthy developments in the past few years have made it necessary to modify the previous guidelines. First, the diagnostic criteria for CLL and its clinical staging have been developed and well defined. Second, although staging systems facilitated entry of comparable and relatively homogeneous groups of patients in clinical trials, the definitions of response (CR) and partial response (PR) were not uniformly adopted from the previous guidelines in the clinical trials (Tables IA, IB); therefore, comparisons of results obtained in different studies became difficult. Third, there has been an improvement in our understanding of the immunology and biology of CLL. Finally, we are witnessing the emergence of several chemotherapy agents that promise impressive activity in CLL (e.g., 2'-deoxycoformycin [3], fludarabine monophosphate [4, 5]), and thereby offer the potential for improving survival time in this disease. To best identify regimens worthy of continued pursuit in large comparative trials, standardized guidelines for evaluation are essential. A number of laboratory investigations are also presented for which scientific interest is high yet relevance remains to be determined; thus, they are presented as companion studies to the clinical trials. This mechanism allows for flexibility in the testing of these questions and for additional ideas in the future without requiring modification of an entire treatment protocol. The following guidelines were developed to be used as a form of standardization for clinical trials, incorporating current technologies, yet remaining relevant to the general hematology/oncology community. Based on the membership of the Working Group, it is expected that these guidelines will serve as the criteria for most clinical trials in the near future.

Prognostic factors in chronic lymphocytic leukemia

The Rai staging system is widely used and is easy to apply in clinical practice. The system introduced by Binet et al offers an advantage that it consists only of three stages and, therefore, is more practical for initiation of controlled therapeutic trials than the five-stage Rai system. However, when we take into consideration the survival curves, it is important to note that the Rai system has three groups (and not five), low risk (stage O), intermediate risk (stages I and II), and high risk (stages III and IV). These groups are roughly equivalent to Binet's A, B, and C stages, respectively. Although the IWCLL has recommended a unified, integrated method of combining Binet and Rai systems, in practice, however, such a combination is cumbersome and unusable. Both systems, however, suffer from an important limitation--they cannot predict for the large majority of patients in the low and intermediate risk groups (Binet's stages A and B and Rai's O, I, and II) who will have an indolent course and good prognosis in contrast to those in the same stages whose disease will progress rapidly. It is necessary, therefore, to combine the bone marrow histology findings, the lymphocyte doubling time and the threshold values of blood lymphocyte count with the clinical staging systems to distinguish between indolent disease course and aggressive disease on a prospective basis within a given clinical stage.

Circulating monoclonal IgM proteins in B cell chronic lymphocytic leukemia: their identification, characterization and relationship to membrane IgM

Accumulated evidence indicates that there is a circulating monoclonal Ig protein related to the leukemic cell-associated Ig in the majority of patients with B cell chronic lymphocytic leukemia (CLL) despite the failure to demonstrate such a protein by conventional serum electrophoresis. Methodology has been developed to reveal these hidden monoclonal bands and to show that they are related to the leukemia-associated membrane Ig (mIg). Of nine CLL cases with stainable mIgM and without discernable plasma Ig bands, marked hypogammaglobulinemia was evident in six. In the other three, a significant amount of protein was present in the gamma region. IgM was isolated from the plasma of these patients by affinity chromatography with Sepharose-4B, conjugated with affinity purified anti-human IgM antibodies. One to 3 mg were isolated from 20 to 40 ml of plasma. Agarose electrophoresis revealed a monoclonal Ig band in the isolated IgM in all cases. Eight of these IgM proteins were analyzed by high-pressure liquid chromatography. Five were found to be pentameric IgM. In the remaining three, various amounts of monomeric IgM were detected. Attempts to make anti-idiotypic antibodies to the isolated proteins have been successful. Thus far, a rabbit anti-idiotypic antiserum was obtained in one case and two mouse monoclonal anti-idiotypic antibodies in two additional cases. Immunofluorescence analysis revealed that plasma IgM and mIgM shared similar idiotypic determinants. One other monoclonal antibody was shown to be specific for a V region marker of a minor Ig population. These findings indicate that B leukemic lymphocytes do secrete a small amount of IgM and lend further support to the thesis that the maturation defect in CLL is incomplete. It is also feasible to isolate the secreted IgM and to produce anti-idiotypic antibodies to them. In view of the potential therapeutic effect of anti-idiotypic antibodies, this may offer an alternative and efficient approach to generate a large panel of anti-idiotypic antibodies for clinical trials. The possibility also exists that this approach is applicable to other B cell proliferative disorders such as the non-Hodgkin B cell lymphomas.

Circulating monoclonal IgM proteins in B cell chronic lymphocytic leukemia: their identification, characterization and relationship to membrane IgM

Accumulated evidence indicates that there is a circulating monoclonal Ig protein related to the leukemic cell-associated Ig in the majority of patients with B cell chronic lymphocytic leukemia (CLL) despite the failure to demonstrate such a protein by conventional serum electrophoresis. Methodology has been developed to reveal these hidden monoclonal bands and to show that they are related to the leukemia-associated membrane Ig (mIg). Of nine CLL cases with stainable mIgM and without discernable plasma Ig bands, marked hypogammaglobulinemia was evident in six. In the other three, a significant amount of protein was present in the gamma region. IgM was isolated from the plasma of these patients by affinity chromatography with Sepharose-4B, conjugated with affinity purified anti-human IgM antibodies. One to 3 mg were isolated from 20 to 40 ml of plasma. Agarose electrophoresis revealed a monoclonal Ig band in the isolated IgM in all cases. Eight of these IgM proteins were analyzed by high-pressure liquid chromatography. Five were found to be pentameric IgM. In the remaining three, various amounts of monomeric IgM were detected. Attempts to make anti-idiotypic antibodies to the isolated proteins have been successful. Thus far, a rabbit anti-idiotypic antiserum was obtained in one case and two mouse monoclonal anti-idiotypic antibodies in two additional cases. Immunofluorescence analysis revealed that plasma IgM and mIgM shared similar idiotypic determinants. One other monoclonal antibody was shown to be specific for a V region marker of a minor Ig population. These findings indicate that B leukemic lymphocytes do secrete a small amount of IgM and lend further support to the thesis that the maturation defect in CLL is incomplete. It is also feasible to isolate the secreted IgM and to produce anti-idiotypic antibodies to them. In view of the potential therapeutic effect of anti-idiotypic antibodies, this may offer an alternative and efficient approach to generate a large panel of anti-idiotypic antibodies for clinical trials. The possibility also exists that this approach is applicable to other B cell proliferative disorders such as the non-Hodgkin B cell lymphomas.