Treatment Of B-cell non-Hodgkin Lymphoma Research Articles

Ongoing Trials with Yttrium 90–Labeled Ibritumomab Tiuxetan in Patients with Non-Hodgkin's Lymphoma

Targeted radiation therapy or radioimmunotherapy has been an important recent advance in the treatment of patients with B-cell non- Hodgkin's lymphoma (NHL). Yttrium 90–labeled ibritumomab tiuxetan (Zevalin®) comprises the murine monoclonal antibody ibritumomab, the linker chelator tiuxetan, and the radiolabeled isotope yttrium 90. Yttrium 90 ibritumomab tiuxetan has been shown to be efficacious in the treatment of B-cell NHL. Initial phase I/II trials established the therapeutic dose of ibritumomab tiuxetan for low-grade NHL to be 0.4 mCi/kg, or 0.3 mCi/kg for patients with mild thrombocytopenia. Currently, there are many ongoing trials of ibritumomab tiuxetan with different dose schedules and dose intensities in combination with chemotherapy and autologous or allogeneic stem cell transplantation in an attempt to improve response rate and duration and to study its effectiveness in other B-cell lymphomas including mantle cell lymphoma, and chronic lymphocytic leukemia. This article reviews the ongoing trials with 90Y ibritumomab tiuxetan. Radioimmunotherapy has great promise, and the safe incorporation of 90Y ibritumomab tiuxetan into treatment will hopefully result in improved survival for patients with NHL.

Oxaliplatin/rituximab combination in the treatment of intermediate-low grade non-Hodgkin's lymphoma of elderly patients

High and intermediate grade non-Hodgkin's lymphomas (NHL) require treatments with aggressive chemotherapy schedules. However, low grade NHLs display a low chemoresponsiveness and patients aged >65 years often do not tolerate anthracycline and corticosteroid-containing chemotherapy regimens. Therapeutic options in this subset of patients are watchful waiting, oral alkylating agents, purine nucleoside analogues, combination chemotherapy, interferon and monoclonal antibodies. The approval of rituximab, an unconjugated chimeric antibody against the CD20 antigen for the treatment of B-cell NHL marked a milestone in the development of antibody treatment. Moreover, promising results have also been found with oxaliplatin in patients with NHL and reversible, cumulative, peripheral sensory neuropathy is the principle dose-limiting factor of oxaliplatin therapy. On the basis of these considerations we have performed a feasibility study in NHL in patients aged >65 years using as schedule: 130 mg/m2 oxaliplatin every 21 days and 375 mg/m2 rituximab weekly. We have enrolled 8 patients, 2 males and 6 females (mean age 69.2+/-3.1 years; median, 67 years) affected by intermediate or high grade stage III/IV NHL. Six patients have cardiac abnormalities (myocardial function between 45 and 50%) and 1 increase of transaminasemia due to active chronic hepatitis. All the patients included in the study were treated for at least 3 cycles and 31 cycles were completed. We have recorded grade I/II (CTC) neurotoxicity in 30%, grade I anemia in 25% and grade I neutropenia in 20% of the patients. No infusional reactions, liver or renal toxicity neither nausea and/or vomiting were recorded. One complete response, 3 partial response and 3 minimal response were obtained at 11 months of median time follow-up. These results demonstrate the feasibility of this schedule which offers a suitable alternative regimen to treat elderly patients with NHL and shows a good efficacy and an acceptable toxicity profile.

Development of radioimmunotherapy for the treatment of non-Hodgkin's lymphoma.

The goal of radioimmunotherapy (RIT) is to target radiation to tumor tissue with radiolabeled monoclonal antibodies while limiting toxicity to normal cells. Radionuclide emission properties and the chemical stability of radioimmunoconjugates are important factors that contribute to the effectiveness of RIT. A 1994 review of early clinical trials with RIT in treating non-Hodgkin's lymphoma (NHL) reported a 40% response rate with nonmyeloablative doses of yttrium 90 (90Y) or iodine 131 (131I) antibodies. Of the radiolabeled antibodies currently in pivotal trials or approved by the US Food and Drug Administration, those targeted to the CD20 antigen have produced the highest response rates. Response rates for ibritumomab tiuxetan, the recently approved RIT for NHL, ranged from 74% in rituximab-refractory patients to 80% in the pivotal trial. The iodine-labeled anti-B1 antibody has been evaluated in previously treated and previously untreated patients with NHL. In the pivotal trial, previously treated patients achieved a response rate of 65%, whereas previously untreated patients had a 97% response rate. Radiolabeled anti-HLA DR has been evaluated in NHL patients and has demonstrated a 53% response rate. Murine antibody LL2, which recognizes the CD22 antigen, has been radiolabeled with 90Y and 131I, with response rates ranging from 15% to 33%. The development of radioimmunotherapy has led to meaningful advances in the treatment of B-cell NHL.

Expression of complement inhibitors CD46, CD55, and CD59 on tumor cells does not predict clinical outcome after rituximab treatment in follicular non-Hodgkin lymphoma

Rituximab is a chimeric monoclonal antibody that targets B-cell-specific antigen CD20 and an effective treatment for B-cell non-Hodgkin lymphoma. Although it is readily used in clinical practice, the exact mechanism of its antitumor effect is unclear. One potential mechanism involves complement-mediated cytotoxicity. It has been shown that rituximab induces complement-mediated cytotoxicity in follicular lymphoma cells in vitro, and complement inhibitors CD55 and CD59 may regulate this process. To determine whether complement inhibitors play a role in regulating the antitumor effect of rituximab, the expression of complement inhibitors CD46, CD55, and CD59 was analyzed in pretreatment tumor cells from 29 rituximab-treated follicular lymphoma patients. Among them, 8 patients achieved complete responses, 11 patients achieved partial responses, and 10 patients showed no or minimal responses to rituximab treatment. Expression of surface CD20, CD46, CD55, and CD59 was determined by 2-color flow cytometry. Although the CD59 level was slightly lower in the complete response group, there was no statistically significant difference in the expression of individual complement inhibitor CD46 (mean channel fluorescence [MCF]: NR, 26.4; PR, 21.9; CR, 29.9), CD55 (MCF: NR, 16.4; PR, 14.9; CR, 23.2), or CD59 (MCF: NR, 41.6; PR, 40.6; CR, 30.6), the combination of any 2 inhibitors, or all 3 on tumor cells from 3 response groups. In addition, there was no difference in the rituximab-induced complement-mediated cytotoxicity in an in vitro assay using tumor cells from 3 response groups. Thus, CD46, CD55, and CD59 expression on pretreatment tumor cells, or their susceptibility to in vitro complement-mediated killing, does not predict clinical outcome after rituximab treatment.

Radioimmunotherapy with iodine 131I tositumomab for relapsed or refractory B-cell non-Hodgkin lymphoma: updated results and long-term follow-up of the University of Michigan experience

CD20-targeted radioimmunotherapy is a promising new treatment for B-cell non-Hodgkin lymphoma (NHL). We now provide updated and long-term data on 59 chemotherapy-relapsed/refractory patients treated with iodine 131I tositumomab in a phase I/II single-center study. Fifty-three patients received individualized therapeutic doses, delivering a specified total-body radiation dose (TBD) based on the clearance rate of a preceding dosimetric dose. Six patients received dosimetric doses only. Dose-escalations of TBD were conducted separately in patients who had or had not undergone a prior autologous stem cell transplant (ASCT) until a nonmyeloablative maximally tolerated TBD was established (non-ASCT = 75 cGy, post-ASCT = 45 cGy). Fourteen additional non-ASCT patients were treated with 75 cGy. Unlabeled antibody was given prior to labeled dosimetric and therapeutic doses to improve biodistribution. Forty-two (71%) of 59 patients responded; 20 (34%) had complete responses (CR). Thirty-five (83%) of 42 with low-grade or transformed NHL responded versus 7 (41%) of 17 with de novo intermediate-grade NHL (P = .005). For all 42 responders, the median progression-free survival was 12 months, 20.3 for those with CR. Seven patients remain in CR 3 to 5.7 years. Sixteen patients were re-treated after progression; 9 responded and 5 had a CR. Reversible hematologic toxicity was dose limiting. Only 10 patients (17%) had human anti-mouse antibodies detected. Long-term, 5 patients developed elevated thyroid-stimulating hormone levels, 5 were diagnosed with myelodysplasia and 3 with solid tumors. A single, well-tolerated treatment with iodine 131I tositumomab can, therefore, produce frequent and durable responses in NHL, especially low-grade or transformed NHL.

Radioimmunotherapy with iodine 131I tositumomab for relapsed or refractory B-cell non-Hodgkin lymphoma: updated results and long-term follow-up of the University of Michigan experience

AbstractCD20-targeted radioimmunotherapy is a promising new treatment for B-cell non-Hodgkin lymphoma (NHL). We now provide updated and long-term data on 59 chemotherapy-relapsed/refractory patients treated with iodine 131I tositumomab in a phase I/II single-center study. Fifty-three patients received individualized therapeutic doses, delivering a specified total-body radiation dose (TBD) based on the clearance rate of a preceding dosimetric dose. Six patients received dosimetric doses only. Dose-escalations of TBD were conducted separately in patients who had or had not undergone a prior autologous stem cell transplant (ASCT) until a nonmyeloablative maximally tolerated TBD was established (non-ASCT = 75 cGy, post-ASCT = 45 cGy). Fourteen additional non-ASCT patients were treated with 75 cGy. Unlabeled antibody was given prior to labeled dosimetric and therapeutic doses to improve biodistribution. Forty-two (71%) of 59 patients responded; 20 (34%) had complete responses (CR). Thirty-five (83%) of 42 with low-grade or transformed NHL responded versus 7 (41%) of 17 with de novo intermediate-grade NHL (P = .005). For all 42 responders, the median progression-free survival was 12 months, 20.3 for those with CR. Seven patients remain in CR 3 to 5.7 years. Sixteen patients were re-treated after progression; 9 responded and 5 had a CR. Reversible hematologic toxicity was dose limiting. Only 10 patients (17%) had human anti-mouse antibodies detected. Long-term, 5 patients developed elevated thyroid-stimulating hormone levels, 5 were diagnosed with myelodysplasia and 3 with solid tumors. A single, well-tolerated treatment with iodine 131I tositumomab can, therefore, produce frequent and durable responses in NHL, especially low-grade or transformed NHL.