ORLANDO, FloridaConventional chemotherapy has limited efficacy against
follicular non-Hodgkin’s lymphoma (NHL), but research reported at the 43rd
Annual Meeting of the American Society of Hematology showed promising
results when conventional regimens were combined with the anti-CD20 drug
tositumomab/I-131 tositumomab (Bexxar).
Oliver W. Press, MD, reported for the Southwest Oncology Group on
SWOG-9911, a phase II trial of CHOP (cyclophosphamide [Cytoxan, Neosar],
doxorubicin HCl, vincristine [Oncovin], prednisone) followed by tositumomab/I-131
tositumomab for newly diagnosed follicular non-Hodgkin’s lymphomas. John
P. Leonard, MD, reported a trial of fludarabine (Fludara) followed by
tositumomab/I-131 tositumomab for follicular low-grade lymphoma.
CHOP Followed by Radioimmunotherapy
"Advanced follicular lymphomas are incurable with conventional
chemotherapy regimens. Standard chemotherapy and radiolabeled antibodies
each cause remission but are not curative, so we decided to try combining
these modalities," Dr. Press said. He is professor of medicine in the
Department of Medical Oncology at the University of Washington in Seattle.
Patients were treated with six cycles of standard CHOP chemotherapy
(cyclophosphamide at 750 mg/m², doxorubicin at 50 mg/m², vincristine at 1.4
mg/m², and prednisone at 100 mg orally for 5 days) given at 3-week intervals
followed by radioimmunotherapy. Four weeks after the completion of the last
cycle of CHOP, patients with either a partial (PR) or complete remission
(CR) underwent dosimetry with 450 mg of unlabeled tositumomab and 35 mg of
trace-labeled I-131 tositumomab. Based on the rate of clearance of this
dosimetric infusion, the subjects were treated with tositumomab labeled with
48 to 115 mCi of I-131 (median: 84 mCi), estimated to deliver 75 cGy to the
whole body. This therapeutic dose was administered 1 to 2 weeks after the
Toxicity and Response Data
Dr. Press said that 102 patients with newly diagnosed follicular
lymphomas (grade 1, 2, or 3) were registered, of whom 92 were eligible for
treatment. Eighty-eight patients were evaluable for toxicity from the CHOP
regimen; 60 patients were evaluable for toxicity from I-131 tositumomab.
This included grade 3 or 4 neutropenia in 52% of patients after CHOP and 15%
of patients after I-131 tositumomab; thrombocytopenia in 1% and 15%; and
febrile neutropenia in 7% and 3%.