Multicenter phase II clinical study of iodine-131-rituximab radioimmunotherapy in relapsed or refractory indolent non-Hodgkin's lymphoma.
OBJECTIVE
To evaluate efficacy and safety of iodine-131 (131I) -rituximab chimeric anti-CD20 antibody radioimmunotherapy in patients with relapsed or refractory indolent non-Hodgkin's lymphoma (NHL).


METHODS
After a standard loading dose of rituximab 375 mg/m2, individualized dosimetry was performed by whole-body gamma imaging of a tracer activity of 131I-rituximab followed by administration of a therapeutic activity of 131I-rituximab to deliver an estimated whole-body radiation absorbed dose of 0.75 Gy.


RESULTS
Ninety-one patients were entered onto the trial: 78 patients (86%) had follicular lymphoma, six patients (7%) had mucosa-associated lymphoid tissue/marginal zone lymphoma, and seven patients (8%) had small lymphocytic lymphoma. The objective overall response rate (ORR) was 76%, with 53% attaining a complete response (CR) or CR unconfirmed (CRu). Median duration of response for patients achieving CR/CRu was 20 v 7 months for those with a partial response (P = .0121). Median progression-free survival for the entire cohort was 13 months, with 14% remaining relapse free beyond 4 years. Median follow-up was 23 months, with a 4-year actuarial survival rate of 59% +/- 10%. Toxicity was principally hematologic; grade 4 thrombocytopenia occurred in 4% and neutropenia occurred in 16% of patients, with nadirs at 6 to 7 weeks after treatment.


CONCLUSIONS
131I-rituximab radioimmunotherapy of relapsed or refractory indolent NHL achieves high ORR and CR rates with minimal toxicity.
Leahy
Michael F
MF
Department of Haematology, University of Western Australia, Fremantle Hospital, Fremantle, Western Australia. Michael.Leahy@health.wa.gov.au
Seymour
John F
JF
Hicks
Rodney J
RJ
Turner
J Harvey
JH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000009:adverse effects / Q000627:therapeutic use*; D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use*; D016393:Lymphoma, B-Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D016499:Radioimmunotherapy / Q000009:adverse effects / Q000379:methods; D011879:Radiotherapy Dosage; D000069283:Rituximab; D016019:Survival Analysis; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014916:Whole-Body Irradiation
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents; D007457:Iodine Radioisotopes; D000069283:Rituximab