Clinical outcomes of post-remission therapy using 90yttrium ibritumomab tiuxetan (Zevalin®) for high-risk patients with diffuse large B-cell lymphoma

Radioimmunotherapy in Oncology: Overview of the Last Decade Clinical Trials

Simple Summary

Monoclonal antibody-bearing radionuclides have been under clinical investigation over the last two decades for their use in theranostic (diagnostic and therapeutic) applications in cancer. However, despite the numerous trials that have been conducted, only two radioimmunotherapies (RIT) have been approved by the FDA for the targeted therapy of hematologic tumors expressing CD20 antigens. Moreover, RIT applications for solid cancers faced major issues—such as radiotoxicity due to low antibodies penetrance requiring substantial curative dose—where new discoveries concerning antibody engineering or radionuclides are trying to overcome. Here, we performed an overview of the last 11-year clinical trials involving RIT for solid and non-solid cancers conducted either with full antibodies or antibody fragments. We discussed the low-to-moderate efficiency of RIT compared to conventional therapies and described the last advances in clinic for antibodies carriers (F(ab′)₂, Fab′, ScFv). Finally, we discussed about the complexity of RIT as a therapy and depicted both the issues and the prospects of such a strategy.

Abstract

The specific irradiation of tumors with selective radiolabeled antibodies constitutes an attractive therapeutic approach. Consequent preclinical research has been conducted by both biologists to identify pertinent targets and to select corresponding antibodies (mAb) and by radiochemists to radiolabel mAbs. These numerous preclinical investigations have ascertained the therapeutic interest of radioimmunotherapy (RIT) protocols in mice models. Here, we summarize the clinical studies that have been performed the last decade, including clinical trials (phases I, II, and III), prospective and retrospective studies, and cases series. We thereby reported 92 clinical studies. Among them, 62 concern the treatment of hematological malignancies, and 30 concern solid tumors. For hematologic diseases, the analysis was complex due to the high discrepancy of therapeutic strategies (first-line therapy, consolidation, stem cell transplantation conditioning) as well as the high variety of malignancies that were treated. The clinical studies from the last decade failed to expand anti-CD20 RIT indications but confirmed that RIT using radiolabeled anti-CD20 remains a pertinent choice for patients with relapse follicular lymphomas. For solid tumors, the positive benefit of RIT is more mitigated, apart for few malignancies that can be treated locally. Clinical trials also demonstrated the potential of some antibody formats, such as F(ab′)₂, which has already been approved by the China State FDA under the trend name Licartin®. Despite disparate results, mAb fragments are an interesting prospect for the improvement of RIT efficiency as well as for pretargeted strategies that delay the injection of radioactive treatments from the mAb ones.

Radioimmunotherapy with (131)I-rituximab as consolidation therapy for patients with diffuse large B-cell lymphoma

PURPOSE

The aim of this study was to assess the clinical activity and toxicity of (131)I-rituximab as consolidation therapy for patients with diffuse large B-cell lymphoma (DLBCL) who were treated with R-CHOP (rituximab, cyclophosphamide, vincristine, doxorubicin, and prednisolone).

METHODS

Patients who had been diagnosed with advanced stage (Ann Arbor III or IV) or bulky stage II DLBCL and achieved complete or partial response after six to eight cycles of R-CHOP were enrolled.

RESULTS

A total of 16 patients were enrolled and treated with a single dose of (131)I-rituximab as consolidation therapy after the completion of six or eight cycles of R-CHOP between December 2005 and June 2011. This trial was terminated before the scheduled enrollment owing to low recruitment. Among the 16 patients who were treated with consolidative (131)I-rituximab, 6 achieved complete response (CR) after three cycles of R-CHOP, and another 9 patients further achieved CR after the completion of six or eight cycles of R-CHOP. During the median follow-up period of 73 months, only four patients (25 %) experienced relapse. Two-year relapse-free survival was 88 %, and 5-year relapse-free survival was 81 %. Grade 3 or 4 treatment-related toxicity occurred in four patients and included neutropenia and thrombocytopenia.

CONCLUSIONS

(131)I-rituximab showed promising efficacy as consolidation treatment for patients with DLBCL. A future randomized phase III study to confirm our results is warranted.

The use of Yttrium-90 Ibritumomab Tiuxetan ((90)Y-IT) as a consolidation therapy in high-risk patients with diffuse large B-cell lymphoma ineligible for autologous stem-cell transplantation

Aim of the study

To evaluate the efficacy and safety of Yttrium-90 Ibritumomab Tiuxetan (⁹⁰Y-IT) as a consolidation therapy in the management of DLBCL.

Material and methods

Patients with primary refractory or high-risk DLBCL (n = 18), ineligible for autologous stem-cell transplantation, were included in a retrospective study performed at three centers by the Polish Lymphoma Research Group (PLRG). All patients (mean age 61, range 35–82) either didn't achieve a complete response or didn't complete the scheduled therapy due to its complications. Response rates (CR, PR, SD, PD) according to Cheson criteria, overall survival (OS), progression-free survival (PFS) and adverse effects of radioimmunotherapy were analyzed.

Results

Consolidation radioimmunotherapy increased the CR rate from 38% (n = 7) to 82% (n = 15). One patient remained in PR, one patient remained in SD, while one patient remained in PD. During a median follow-up of five years, 11 patients (62%) were alive with no recurrence, 4 patients (22%) were alive with relapse while 3 patients (16%) died. There was no statistically significant difference in PFS between those in CR and those in PR before ⁹⁰Y-IT.

Conclusions

Radioimmunotherapy is an effective consolidation therapy for high risk/refractory DLBCL patients and worthy of further investigation in prospective trials.

Radioimmunotherapy with (131)i-rituximab in a patient with diffuse large B-cell lymphoma relapsed after treatment with (90)y-ibritumomab tiuxetan

We report a case that demonstrates the efficacy of radioimmunotherapy (RIT) with radioiodinated rituximab ((131)I-rituximab) for relapsed diffuse large B-cell lymphoma (DLBCL). A 79-year-old male patient with DLBCL initially achieved a complete response (CR) after six cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) therapy. However, the lymphoma relapsed 20 months later. Although the patient had achieved a second and a third CR after two cycles of (90)Y-ibritumomab tiuxetan, he experienced a third relapse approximately 3 years later. Between March and June 2011, the patient received three cycles of (131)I-rituximab. Although he had achieved partial response after the second cycle, the disease progressed after the third cycle, and the total progression-free survival was thus 5 months. The patient suffered only relatively mild toxicity (grade 1 thrombocytopenia) during treatment. RIT with (131)I-rituximab is therefore potentially effective in patients with relapsed DLBCL, even after the failure of (90)Y-ibritumomab tiuxetan therapy.