Rapid, high-yield production in plants of individualized idiotype vaccines for non-Hodgkin's lymphoma.

BACKGROUND: Animal and clinical studies with plant-produced single-chain variable fragment lymphoma vaccines have demonstrated specific immunogenicity and safety. However, the expression levels of such fragments were highly variable and required complex engineering of the linkers. Moreover, the downstream processing could not be built around standard methods like protein A affinity capture. DESIGN: We report a novel vaccine manufacturing process, magnifection, devoid of the above-mentioned shortcomings and allowing consistent and efficient expression in plants of whole immunoglobulins (Igs). RESULTS: Full idiotype (Id)-containing IgG molecules of 20 lymphoma patients and 2 mouse lymphoma models were expressed at levels between 0.5 and 4.8 g/kg of leaf biomass. Protein A affinity capture purification yielded antigens of pharmaceutical purity. Several patient Igs produced in plants showed specific cross-reactivity with sera derived from the same patients immunized with hybridoma-produced Id vaccine. Mice vaccinated with plant- or hybridoma-produced Igs showed comparable protection levels in tumor challenge studies. CONCLUSIONS: This manufacturing process is reliable and robust, the manufacturing time from biopsy to vaccine is <12 weeks and the expression and purification of antigens require only 2 weeks. The process is also broadly applicable for manufacturing monoclonal antibodies in plants, providing 50- to 1000-fold higher yields than alternative plant expression methods.

Idiotype vaccines for human B-cell malignancies.

After twenty years of use in humans, customized idiotypic vaccination yet remains a non-approved, experimental therapeutic option for patients with lymphoma and myeloma. Potentially applicable to all B-cell malignancies whose cells express a clonal immunoglobulin or its epitopes on their surface, this treatment is designed to prevent disease recurrence or progression. Mostly used in follicular lymphoma patients so far, idiotype vaccines have clearly shown biological efficacy, clinical efficacy and clinical benefit in this setting, although no study aiming at regulatory approval of the procedure has been able to meet its main clinical endpoints. In mantle cell lymphoma, only biological efficacy has been proven for idiotypic vaccination, while in multiple myeloma a limited number of studies support the notion of biological and perhaps even clinical efficacy, although no credible evidence of clinical benefit has still emerged. Idiotype vaccines have been produced and administered in a number of substantially different manners. Therefore, the results of most clinical trials cannot be easily compared, and even less pooled together in meaningful meta-analyses. A more creative and yet scientifically sound way to design clinical trials of customized active immunotherapies will be key to the future development of idiotype vaccines, particularly considering that we currently lack any clinical or biological indicator to possibly predict which patients are more likely to respond to idiotypic vaccination from an immunologic point of view. This review aims at summarizing the multifaceted success achieved by idiotype vaccines, as well as at outlining the challenges awaiting them in the near future: how to improve feasibility, immunogenicity and efficacy, as well as how to confirm benefit and gain regulatory approval.

[Anemia in chronic lymphatic leukemia: is erythropoietin the solution?]. / La anemia en la leucemia linfática crónica: Es la eritropoyetina la solución del problema?

Anemia is a common complication in the clinical course of chronic lymphocytic leukemia. Low hemoglobin levels both correlate with an adverse prognosis and adversely affect the quality of life of chronic lymphocytic leukemia patients. Different physiopathological phenomena may lead to anemia: marrow infiltration, hypersplenism, immune hemolysis or toxicity of chemotherapy. Treatment with human recombinant erythropoietic agents has been shown to be effective for anemia associated with different lymphoproliferative syndromes. This paper analyses the available evidence on erythropoietic agent treatment for chronic lymphocytic leukemia associated anemia. The comparative effect of different dosage schemes, the role of possible response-prediction factors such as the endogenous erythropoietin level and the results achieved using darbopoietin alpha are reviewed.

Anti-idiotype antibodies in cancer treatment.

As a cancer immunotherapy tool, idiotypes (Ids) have been used in different ways over the last three decades, depending on the actual human tumor cell target. It all started with passive, monoclonal, anti-Id antibody treatment of B-cell lymphoma, a setting in which results were tantalizing, but logistics unsustainable. It then moved toward the development of anti-Id vaccines for the treatment of the same tumors, a setting in which we have recently provided the first formal proof of principle of clinical benefit associated with the use of a human cancer vaccine. Meanwhile, it also expanded in the direction of exploiting the antigenic mimicry of some Ids with Id-unrelated, tumor-associated antigens for the immunotherapy of a number of solid tumors, a setting in which clinical results are still far from being consolidated. All in all, over the years Id-based immunotherapy has paved the way for a number of seminal therapeutic improvements for cancer patients, including the development of most if not all Id-unrelated monoclonal antibodies that have recently revolutionized the field.

The results of consolidation with autologous stem-cell transplantation in patients with peripheral T-cell lymphoma (PTCL) in first complete remission: the Spanish Lymphoma and Autologous Transplantation Group experience.

BACKGROUND: Peripheral T-cell lymphoma (PTCL) is a heterogeneous group of aggressive lymphomas associated with poor prognosis with standard chemotherapy. Consolidation with autologous stem-cell transplantation (ASCT) may improve survival. We present 74 patients transplanted in first complete response (CR) from the Spanish Lymphoma and Autologous Transplantation Group cooperative group. PATIENTS AND METHODS: Median age was 46 years. Eighty-eight percent presented advanced (III-IV) Ann Arbor stage; 53% had B symptoms; 52% had high lactate dehydrogenase; 65% had two or three risk factors of the adjusted-International Prognostic Index; 58% presented a high Tumor score and in 14% more than two adverse factors of the Prognostic Index for peripheral T-cell lymphoma (PIT) were observed. RESULTS: With a median follow-up of 67 months from diagnosis, the 5-year overall survival (OS) was 68% and progression-free survival (PFS) reached 63%. The multivariate analysis showed that the only factor associated with a shorter OS and PFS was the presence of more than two risk factors from the PIT risk system. CONCLUSIONS: In a retrospective study with a prolonged follow-up, consolidation with ASCT in CR patients who had presented unfavorable prognostic factors at diagnosis substantially increased the OS and PFS when compared with conventional chemotherapy. The PIT risk system identified 14% of patients without benefit from ASCT consolidation. Thus, other innovative therapies are still necessary in certain cases.

[The immunotherapy potential of agonistic anti-CD137 (4-1BB) monoclonal antibodies for malignancies and chronic viral diseases]. / El potencial de la inmunomodulación con anticuerpos monoclonales anti-CD137 (4-1BB) para terapia de enfermedades malignas e infecciones virales crónicas.

Pharmacological intervention on the immune system to achieve more intense lymphocyte responses has potential application in tumour immunology and in the treatment of chronic viral diseases. Immunostimulating monoclonal antibodies are defined as a new family of drugs that augment cellular immune responses. They interact as artificial ligands with functional proteins of the immune system, either activating or inhibiting their functions. There are humanized monoclonal antibodies directed to the inhibitory receptor CD152 (CTLA-4) that are being tested in clinical trials with evidence of antitumoural activity. As a drawback, anti-CTLA-4 monoclonal antibodies induce severe autoimmunity reactions in a fraction of the patients. Anti-CD137 monoclonal antibodies have the ability to induce potent immune responses mainly mediated by cytotoxic lymphocytes with the result of frequent complete tumour eradications in mice. Comparative studies in experimental models indicate that the antitumour activity of anti-CD137 monoclonal antibodies is superior to that of anti-CD152. CD137 (4-1BB) is a leukocyte differentiation antigen selectively expressed on the surface of activated T and NK lymphocytes, as well as on dendritic cells. Monoclonal antibodies acting as artificial stimulatory ligands of this receptor (anti-CD137 agonist antibodies) enhance cellular antitumoural and antiviral immunity in a variety of mouse models. Paradoxically, anti-CD137 monoclonal antibodies are therapeutic or preventive in the course of model autoimmune diseases in mice. In light of these experimental results, a number of research groups have humanized antibodies against human CD137 and early clinical trials are about to start.

[Past, present and future of anti-idiotype vaccination]. / Pasado, presente y futuro de la vacunación anti-idiotipo.

Cancer vaccines are conceived as therapeutic tools, in contrast to the prophylactic vaccines used to fight against infectious diseases. Among the most potent therapeutic vaccines, anti-idiotype vaccination is directed against the tumor idiotype, the only well-characterized tumor antigen displayed in neoplastic B-cells. Anti-idiotype vaccines have demonstrated clinical benefit against follicular lymphoma and are currently being evaluated in two different phase III clinical trials. Additional emerging strategies, which include the use of dendritic cells and the production of vaccines via molecular means will surely allow us to draw important conclusions concerning the treatment of cancer patients.

[Active immunotherapy in the treatment of haematological neoplasias]. / Inmunoterapia activa en el tratamiento de neoplasias hematológicas.

The continuous search for therapeutic approaches that improve the conventional treatments of neoplasms, together with an improved understanding of the immune system, has led in recent years to the development of Immunotherapy. Basically, a distinction can be made between two forms of immunotherapy: passive immunotherapy, which consists in the transfer of antibodies or cells previously generated in vitro that are directed against the tumour, and active immunotherapy, which attempts to activate in vivo the immune system and induce it to elaborate a specific response against the tumor antibodies. Hematological neoplasms, specifically some B lymphomas, express in their membrane an immunoglobulin that is considered a specific antigen of the tumour, which is why these diseases have become the ideal target for immunotherapy treatments. There are many alternatives, ranging from protein vaccines, which have already shown clinical benefits, to those of the second generation, which make use of the new techniques of molecular biology to increase the efficacy of the vaccines and obtain their production in a quicker and less costly way, but with which there are not yet definitive clinical results.

A single prior course of BCNU-cisplatin chemotherapy has a significant deleterious effect on mobilization kinetics of otherwise untreated patients.

Extensive prior treatment with cytotoxic agents is associated with impaired mobilization of hematopoietic cells. To assess the effect of a single course of standard-dose chemotherapy (CT), we compared the results of filgrastim-induced mobilization among two sequential groups of grade III-IV malignant glioma patients included in a hematopoietic transplantation program. The first group (21 patients) had never been treated with CT until 2 days after surgery, when they received a course of 100 mg/m2 BCNU (i.v.) and 100 mg intracarotid cisplatin for cytoreduction (not for mobilization). At 1 month after this CT, they were mobilized with 12 microg/kg filgrastim. The second group (22 patients) was mobilized with the same dose of filgrastim directly after the surgery, without having ever received any prior CT. The blood level of CD34+ cells was significantly lower in the CT-treated patients, both on the fourth day of filgrastim (15 vs 36 cells x 10(6)/l; P=0.01) and on the fifth (25 vs 58 cells x 10(6)/l; P=0.003), as it was the number of CD34+ cells collected per apheresis (1.3 vs 3.5 x 10(6)/l; P<0.0005). The toxic effect of a single course of BCNU-cisplatin CT led to significant impairment of the filgrastim-induced mobilization response.

Indolent lymphoma: the pathologist's viewpoint.

Indolent lymphomas have recently been the object of numerous studies, which have focused on new aspects relevant both for the better comprehension of their histogenesis and the identification of new therapeutic strategies. As marginal-zone lymphoma (MZL) represents the category of indolent lymphomas that has obtained more benefit from such an approach, the authors focused on the most recent achievements and not yet solved controversies in this area. In spite of their postulated common derivation, the three categories of MZL of the WHO Classification appear dissimilar. In fact, they show significant molecular differences among them as well as a certain heterogeneity within each group. By no means, there is a cogent need of more refined tools to revise these neoplasms and to produce a more rational grouping. The recent identification of the IRTA gene family corresponding to IG-like receptors differentially expressed in B-cells might contribute to their better understanding.

Efficacy of vinorelbine, epirubicin and prednisone combination regimen in pretreated elderly patients with aggressive non-Hodgkin's lymphoma.

BACKGROUND AND OBJECTIVES: To assess the efficacy and toxic profile of the NAEPP protocol, a regimen including vinorelbine, epirubicin and prednisone, in a particularly troublesome subset of patients: pretreated elderly patients with aggressive non-Hodgkin's lymphoma (NHL). DESIGN AND METHODS: From November 1998 to January 2000, 20 pretreated patients who had all relapsed after first-line VNCOP-B chemotherapy were enrolled in a phase II trial and treated with the NAEPP regimen: vinorelbine (25 mg/m(2) i.v. on days 1 and 8), epirubicin (40 mg/m(2) i.v. on days 1 and 8), and prednisone (40 mg/m(2) on days 1 and 8) with granulocyte colony-stimulating factor administered at 5 mg/kg/day on days 2-5 and days 9-12. Chemotherapy was repeated every 4 weeks for a total of 6 cycles. RESULTS: Six (30%) patients achieved complete remission (CR) and 7 (35%) had partial responses (PR), giving an overall response rate of 65%. The response rate was not affected either by type of relapse presentation (nodal versus nodal plus extranodal), presence of bulky disease, or time of relapse. No major toxic effects were recorded. INTERPRETATION AND CONCLUSIONS: These preliminary data suggest that the NAEPP regimen is an effective combination with a low toxicity profile in elderly pretreated patients with aggressive NHL. Further trials using NAEPP as a consolidation phase following first-line treatment are needed to establish the advantage in terms of CR rate and relapse-free survival in these patients.

Expression of the c-met proto-oncogene and its ligand, hepatocyte growth factor, in Hodgkin disease.

The receptor for hepatocyte growth factor (HGF) is a transmembrane tyrosine kinase that is encoded by the proto-oncogene c-met. Recently, c-MET was detected in Reed-Sternberg (RS) cells from Epstein-Barr virus-positive (EBV(+)) Hodgkin disease (HD). The c-MET, EBER-1, and LMP-1 expression in 45 lymph node biopsies and 12 bone marrow biopsies obtained from patients with HD was analyzed. In addition, HGF levels in serum samples from 80 healthy individuals and 135 HD patients in different phases of disease. In all 45 lymph node and 12 bone marrow samples examined, RS cells expressed c-MET but not HGF(+). These results were independent of the EBV infection. Interestingly, several HGF(+) dendritic-reticulum cells were found scattered around c-MET(+) RS cells. The mean +/- SEM serum HGF levels in HD patients at diagnosis and at the time of relapse were 1403 +/- 91 (95% confidence interval [CI], 1221-1585) and 1497 +/- 242 pg/mL (95% CI, 977-2017), respectively. HGF values were significantly higher than those of healthy individuals (665 +/- 28 pg/mL; 95% CI, 600-721; and P <.001 for both groups of patients) and of HD patients in remission (616 +/- 49 pg/mL; 95% CI, 517-714; and P <.001 for both groups of patients). A significant correlation was found between serum HGF levels and B symptoms at diagnosis (P =.014). In conclusion, this study indicates that HGF and c-MET constitute an additional signaling pathway between RS cells and the reactive cellular background, thereby affecting adhesion, proliferation, and survival of RS cells. Furthermore, the serum concentration of HGF in HD patients may be a useful tool in monitoring the status of disease.

Novel secondary Ig VH gene rearrangement and in-frame Ig heavy chain complementarity-determining region III insertion/deletion variants in de novo follicular lymphoma.

Human germinal center B cell tumors retain the ability of their nontransformed counterparts to somatically hypermutate Ig V genes by nucleotide substitution. Among a survey of 60 primary previously untreated, clonal, follicular lymphomas we have identified a rare V(H) rearrangement variant and two other in-frame nucleotide insertion/deletion variants within complementarity-determining region III of the Ig heavy chain. The neoplastic origin of the V(H) rearrangement variant was directly demonstrated in cells isolated by microdissection from malignant follicles. In all three cases a common clonal origin for the variants was demonstrated by complementarity-determining region III nucleotide sequence homology and shared somatic mutations in germline encoded positions in framework region IV. The monoclonal nature of the tumors was independently confirmed by demonstrating a single t(14;18) translocation breakpoint in the two cases with a detectable translocation. All the variants occurred in functional V(H) rearrangements, which in two cases were directly shown to encode functional Ab molecules. Both recombination-activating genes 1 and 2 were expressed in lymph node tumor cells containing the V(H) rearrangement variant, although recombination-activating gene expression among a panel of lymphomas was not limited to this variant.

Primary mediastinal large B-cell lymphoma with sclerosis: a clinical study of 89 patients treated with MACOP-B chemotherapy and radiation therapy.

BACKGROUND AND OBJECTIVES: Primary mediastinal large B-cell lymphoma (PMLBCL) with sclerosis has recently been recognized as a specific clinical and pathologic entity for which the best therapeutic approach seems to be a combination of chemotherapy and radiotherapy. DESIGN AND METHODS: Between 1989 and 1998, 89 previously untreated patients with PMLBCL with sclerosis were treated with a combination of a third-generation chemotherapy regimen (MACOP-B) and mediastinal radiation therapy. The response evaluations were examined after chemotherapy and at the end of radiotherapy. RESULTS: Twenty-three (26%) patients achieved a complete response (CR) and 59 (66%) obtained a partial response (PR) after the MACOP-B regimen. After radiation therapy, 55/59 (93%) of the patients in PR achieved CR. The CR rate at the end of the treatment was 88% (78/89). Only 7 (8%) patients were non-responders. Among the 78 patients who obtained a CR there were 7 (9%) relapses in a median follow-up of 5 months (all relapses occurred within 9 months); the other 71 patients are currently in continuous CR with a median follow-upof 45 months (range, 4-110 months). Projected overall survival was 86% at 9 years; the relapse-free survival curve of the 78 patients who achieved CR was 91% at 9 years. INTERPRETATION AND CONCLUSIONS: In patients with PMLBCL with sclerosis, combined modality treatment using the MACOP-B chemotherapy regimen and radiation therapy induces a good remission rate with the patients having a greater than 90% chance of surviving disease-free at 9 years. Radiotherapy often plays a pivotal role in obtaining CR status.

Identification of the B-cell tumor-specific molecular fingerprint using non-radiolabelled PCR consensus primers.

BACKGROUND: The complementarity determining region 3 (CDR3) of the immunoglobulin (Ig) heavy chain variable region (VH) is the most reliable molecular fingerprint for most if not all human B cells. The nucleotide sequence encoding for any B-cell tumor-specific VH CDR3 is currently identified by PCR sequencing based on procedures involving the usage of either radioactive materials, patient/family-specific primers, or bacterial cloning. PATIENTS AND METHODS: In six consecutive patients with follicular lymphoma we assessed the feasibility of a method that allows for identification of the tumor-specific VH CDR3 using consensus primers while avoiding both radioactive materials and bacterial cloning procedures. RESULTS: The tumor-specific VH CDR3 was successfully identified in all six patients in nearly half the time typically required by any other method currently utilized. The feasibility of the proposed method was not significantly affected either by the tumor-specific Ig isotype, or by the tumor infiltration in the original biopsy specimen. In the three patients for whom tumor specimen-derived hybridomas were available, the tumor-specific VH CDR3 was also found in at least 8 of 10 of them. CONCLUSIONS: The proposed method allows the ability to quickly identify the B-cell tumor-specific VH CDR3 using consensus primers while avoiding radioactive materials and bacterial cloning procedures.

Role of anti-idiotype vaccines in the modern treatment of human follicular lymphoma.

Cancer vaccines are currently conceived as therapeutic tools, in contrast to the prophylactic vaccines that have resolved the problem of a number of infectious diseases. Among the former, anti-idiotype vaccines for human follicular lymphoma have begun to produce tangible clinical results. Just 10 years ago it was not even known whether patients could be immunized against their own tumor antigens and now as many as two independent Phase III clinical trials based on this finding are underway. The rapidity of this development encourages the hope that active immunotherapy may soon become decisive in oncology. For the time being, many important results have already been achieved: the evidence of vaccine-induced, tumor-specific humoral/cellular responses and the first documented molecular remissions following vaccination.

Long-term follow-up after fludarabine treatment in pretreated patients with chronic lymphocytic leukemia.

BACKGROUND AND OBJECTIVES: A study update to assess long-term survival following fludarabine salvage treatment in previously treated patients with chronic lymphocytic lymphoma (CLL). DESIGN AND METHODS: From September 1992 to December 1995, 74 patients with advanced, relapsing B-cell CLL were enrolled in the study. Fludarabine was given for 5 consecutive days at the dose of 25 mg/m2/day in a 30 min infusion. Treatment was repeated every 28 days for a maximum of 6 courses.E RESULTS. Nineteen (26%) patients achieved a complete response (CR) and 20 (27%) patients had a partial response (PR), giving an overall response rate of 53%. The median overall survival was 68 months, and there was a strong negative correlation with the number of previous treatments. The median time to progression was 18 months for patients who achieved a CR and 12 months for those with a PR. INTERPRETATION AND CONCLUSIONS: The results obtained with fludarabine alone in this subset of CLL patients indicate the existence of a conspicuous disease-free survival period. This time window could be used to consolidate the initial response with either biological approaches or high-dose therapeutic strategies such as autologous bone marrow transplantation, with the aim of eventual eradication of the disease.

Tumor-specific recognition of human myeloma cells by idiotype-induced CD8(+) T cells.

Immunoglobulin secreted by myeloma cells contains a unique antigenic determinant (idiotype [Id]) that may serve as a tumor-specific antigen. Although Id-protein-specific T-cell responses have been reported in patients with myeloma, it is not known whether primary myeloma tumor cells can present naturally processed Id peptides on their surface as a target. We immunized 2 healthy human stem-cell donors with Id proteins from their recipients. T cells from the immunized donors released high levels of T-helper 1-type cytokines in response to stimulation with myeloma cells from their recipients. The T-cell-mediated cytokine response to tumor cells was blocked by a major histocompatibility complex (MHC) class I monoclonal antibody, whereas the response to soluble Id protein was dependent on MHC class II. To investigate whether Id-specific CD8(+) T cells can recognize and kill autologous myeloma cells, we generated T cells from peripheral blood mononuclear cells from a third patient with myeloma by means of in vitro stimulation with autologous dendritic cells pulsed with Id protein. Tumor-specific lysis of myeloma cells was demonstrated by the lack of killing of autologous nonmalignant B cells or natural killer-sensitive K562 cells. Lysis of autologous myeloma targets was restricted by MHC class I molecules. These data represent the first report of class I-restricted T-cell recognition of fresh autologous myeloma targets and formally demonstrate that human myeloma cells can serve as targets of an Id-specific T-cell response. (Blood. 2000;96:2828-2833)