The Monoclonal Antibodies Campath-1H and Rituximab in theTherapy of Chronic Lymphocytic Leukemia.

The treatment options for chronic lymphocytic leukemia (CLL) beside standard therapy with chlorambucil or other alkylating agents have dramatically increased in the last few years. Promising results have been reported with new cytotoxic agents such as the purine analogues fludarabine and 2-chlordeoxyadenosine, either at first diagnosis or at relapse. Nevertheless, all patients with CLL relapse after initial response. Since residual lymphoma cells are very likely to be the origin of the clinical relapse, there is a need for new therapeutic approaches with different mechanism of action to eliminate these residual cells. These approaches include allogeneic or autologous stem cell transplantation as well as immunotherapeutic strategies. Monoclonal antibodies, either alone or conjugated to toxins or radioisotopes, are thus being actively investigated. In clinical trials the genetically engineered chimeric unconjugated anti-CD20 antibody Rituximab and the humanized unconjugated anti-CD52 antibody Campath-1H achieved the most promising results in the treatment of patients with relapsed or refractory low-grade non-Hodgkin's lymphoma. Thus far there is only little clinical experience with Rituximab in patients with CLL, and the exact role of these agent in the treatment of CLL has still to be determined in ongoing and future trials. As a single agent Campath-1H showed more clinical activity in previously treated CLL patients than Rituximab, with response rates of up to 33% in a multicenter pivotal study. Furthermore, the potential risks of tumor lysis and anaphylaxia for both antibodies and immunosuppression particularly for Campath-1H must be taken into account. The present review will compare the development and the basic principles of these unconjugated monoclonal antibodies and consider their present and potential role in the treatment of patients with CLL. Copyright 2000 S. Karger GmbH, Freiburg

[Hodgkin's lymphoma in nuclear medicine: diagnostic and therapeutic aspects]. / Nuklearmedizinische Aspekte in der Diagnostik und Therapie des Hodgkin-Lymphoms.

Today, diagnostic and therapeutic strategies of Hodgkin lymphoma (HL) with positron emission tomography and radioimmunotherapy include state-of-the-art nuclear medicine which require the cooperation between oncology and nuclear medicine. The benefit of FDG-PET in HL patients with residual tumor masses consists of its high negative predictive value in the therapy control of the disease. The concept of waitful watching in patients with PET-negative residual masses after BEACOPP-chemotherapy will be evaluated in a large multicenter trial of the GHSG (German Hodgkin Study Group). Radioimmunotherapy has been performed in patients with CD20-positive Non-Hodgkin lymphoma for 10 years with promising results. HL is also an excellent target for immunotherapy due to the expression of antigens such as CD25 and CD30. Thus, a new radioimmunoconstruct consisting of the murine anti-CD30 antibody Ki-4 labeled with iodine-131 was developed for patients with relapsed or refractory HL.

Clinical evaluation of ricin A-chain immunotoxins in patients with Hodgkin's lymphoma.

BACKGROUND: Immunotoxins (ITs) consist of cell binding ligands coupled to toxins or their subunits. Hodgkin's lymphoma (HL) is an excellent target for ITs since lymphocyte activation markers such as CD25 and CD30 are expressed in large numbers. The ITs RFT5.dgA (anti CD25) and Ki-4.dgA (anti CD30) were constructed by linking the monoclonal antibodies RFT5 and Ki-4 to deglycosylated ricin A-chain (dgA). Both ITs showed potent specific activity against HL cells in vitro and in vivo in animal models, and were subsequently evaluated in phase I/II clinical trials in humans. PATIENTS AND METHODS: In two separate trials, the ITs were administered i.v. four times every other day over 4 h. The objectives of the phase I trials included the determination of the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), pharmacokinetics, antitumor activity and immune response against the IT. RESULTS: Twenty-seven patients with refractory HL were included in the phase I/II study of RFT5.dgA and 17 patients were included in the phase I study of Ki-4.dgA. The MTD of RFT5.dgA was 15 mg/m(2), whereas that of Ki-4.dgA was 5 mg/m(2). DLTs were related to vascular leak syndrome, consisting of edema, tachycardia, dyspnea, weakness and myalgia. Measurement of serum levels of RFT5.dgA demonstrated a C(max) of 0.2-9.7 micro g/ml with a half-life (t()) varying from 4 to 10.5 h. Peak serum concentration of Ki-4.dgA ranged from 0.23 to 1.7 micro g/ml. In both trials approximately 60% of patients developed human anti-mouse and/or anti-dgA antibodies. Seventeen of 18 patients treated at the MTD of RFT5.dgA were evaluable for clinical response. Responses included two partial remissions (PR), one minor response (MR) and five stable diseases (SD). Fifteen of 17 patients treated with Ki-4.dgA were evaluable for clinical response. Responses included one PR, one MR and two SD. CONCLUSIONS: RFT5.dgA and Ki-4.dgA showed moderate efficacy in heavily pretreated refractory patients with HL. Ki-4.dgA was less well tolerated than RFT5.dgA. This might be due, at least in part, to the formation of Ki-4.dgA/sCD30 complexes.

Phase I study of BBR 2778, a new aza-anthracenedione, in advanced or refractory non-Hodgkin's lymphoma.

BACKGROUND: BBR 2778 is a novel aza-anthracenedione showing no cardiotoxicity and superior activity compared to doxorubicin and mitoxantrone in animal models. Objectives of this phase I study included the determination of the maximum tolerated dose (MTD), the dose limiting toxicity (DLT), clinical pharmacokinetics (PK), and antitumor activity. Patients with relapsed or refractory, advanced non-Hodgkin's lymphoma were included. PATIENTS AND METHODS: Patients were treated with a q1w x 3 schedule on the basis of a modified Fibonacci dose escalation method. Seven groups with a total of twenty-six patients were treated at dosages of 5, 10, 16.5, 25, 34, 56 or 84 mg/m2/w, respectively. RESULTS: DLT was observed on the seventh dose level with neutropenia WHO grade 4 in three of six patients. Pharmacokinetic analysis showed a large volume of distribution (13.5-17.5 l/kg), a high plasma clearance (0.65-1.74 l/h/kg) and a long elimination half-life (14.7-31.9 h). Tumor response included three complete remissions and two partial remissions. CONCLUSIONS: Neutropenia is the DLT of the new aza-anthracenedione BBR 2778. The recommend dose is 84 mg/m2 in a q1w x 3 schedule. PK data are consistent with a linear kinetic of BBR 2778 comparable to mitoxantrone. This new drug shows promising activity in intensively pretreated patients with relapsed or refractory NHL. Based on this results, phase II studies with this new compound are underway.