Iodine I 131 Tositumomab for Patients With Follicular Non-Hodgkin’s Lymphoma (NHL): Overall Clinical Trial Experience by Histology

OncologyONCOLOGY Vol 14 No 3
Volume 14
Issue 3

Iodine-131 tositumomab (Bexxar) is a new radioimmunotherapy in development for the treatment of patients with low-grade or transformed low-grade non-Hodgkin’s lymphoma. The data from five phase I-III studies, which enrolled patients with low-


Iodine-131 tositumomab (Bexxar) is a new radioimmunotherapy in development for the treatment of patients with low-grade or transformed low-grade non-Hodgkin’s lymphoma. The data from five phase I-III studies, which enrolled patients with low-grade NHL or transformed low-grade NHL, were analyzed.

This analysis focuses on 179 patients with follicular small cleaved cell (FSCL) or follicular mixed cell with > 50% small cleaved cell (FML) histology at the time of treatment with tositumomab. Patients had received a median of 2 (range, 0 to 13) prior chemotherapy regimens, and 64 (49%) of 124 patients had failed to respond to their last chemotherapy regimen. The median duration of response to the last chemotherapy regimen was 6 months. Baseline patient characteristics were: median age, 52 years; 107 patients were male; median time from diagnosis to entry was 29 months; 38% of patients had elevated lactic dehydrogenase (LDH); 58% of patients had a positive baseline bone marrow biopsy (< 25% lymphoma).

Patients generally received a single dosimetric dose (450 mg of tositumomab intravenously [IV] followed by 35 mg of tositumomab radiolabeled with 5 mCi of iodine-131 over ½ hour) and then had three whole-body counts obtained over the next 7 days. The whole-body counts were used to calculate the required activity (mCi) to deliver the desired therapeutic dose (65 cGy for platelet counts of 100,000 to 149,999 cells/mm³ and 75 cGy for platelet counts ³ 150,000 cells/mm³). A single therapeutic dose (450 mg of tositumomab antibody IV followed by 35 mg of tositumomab containing an appropriate activity [mCi] of iodine-131 to deliver the specified total-body dose [cGy] over ½ hour) was administered 7 to 14 days after the dosimetric dose.

An overall response (complete and partial) was observed in 145 (81%) patients, and 69 (39%) patients had a complete response (CR). The median duration of response was 11 months (95% confidence interval [CI], 9 to 16 months), and median time to progression (TTP) for responders was 13 months (95% CI, 11 to 19 months). The median duration of CR was 57 months (95% CI, 31 months to not reached). Overall response by histology was: FSCL, 91 (83%) of 110 patients (38% CRs); and FML, 54 (78%) of 69 patients (39% CRs).

The principal toxicity was hematologic: absolute neutrophil count (ANC) was < 500 cells/mm³ in 17% of patients, and platelet count was < 10,000 cells/mm³in 3%. The hematologic nadir typically occurred at week 5 to 6, with recovery by week 8 to 9. Transient, mild to moderate nonhematologic toxicity occurred, with the most frequent events being fatigue (39%), fever (37%), and nausea (36%). Human antimurine antibodies developed in 12% of previously treated patients. Median survival from study entry was 74 months (95% CI, 36 months to not reached).

CONCLUSIONS: These results demonstrate that tositumomab is a safe and effective therapy for the treatment of patients with follicular NHL.

Click here for Dr. Bruce Cheson’s commentary on this abstract.

Articles in this issue

Comparative Economic Analysis of the Treatment of Relapsed Low-Grade B-Cell Non-Hodgkin’s Lymphoma (NHL) in France Using CHOP, Fludarabine, or Rituximab
FHIT Gene, Smoking, and Cervical Cancer
Final Report on the Safety and Efficacy of Retreatment With Rituximab for Patients With Non-Hodgkins Lymphoma
Prospective, Randomized, Controlled Study of Zevalin Radioimmunotherapy Compared to Rituximab Immunotherapy for B-Cell, Non-Hodgkins Lymphoma: Interim Results
IOM Medical Error Estimates Questioned, But Legislation Considered
Less Toxic Therapies for Hodgkin’s Disease May Reduce Secondary Cancers
Preserving Fertility in Young Women With Ovarian Cancer Does Not Decrease Survival
Iodine-131 Tositumomab for Patients With Transformed, Low-Grade Non-Hodgkin’s Lymphoma: Overall Clinical Trial Experience
Survival Rates Significantly Worse For African-Americans With Endometrial Cancer
Rituximab Has Significant Activity in Patients With Chronic Lymphocytic Leukemia
Responders to Rituximab Show Continued Tumor Regression Over Time and a Progression-Free Survival That Correlates With Response Classification
PhRMA Criticizes FDA’s Proposed Rule on Antibiotic Approvals
Phase II Study of Rituximab in Combination With CHOP in Patients With Previously Untreated Intermediate- or High-Grade Non-Hodgkin’s Lymphoma
New Antibiotic Effective in Treating Gram-Positive Bacteremia
Reduced-Dose Zevalin Radioimmunotherapy for Relapsed or Refractory B-Cell Non-Hodgkin&#146;s Lymphoma Patients With Preexisting Thrombocytopenia: Report of Interim Results of a Phase II Trial
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