• non-Hodgkin lymphoma;
  • radioimmunotherapy;
  • iodine I-131 tositumomab;
  • chemotherapy;
  • monoclonal antibody



Iodine I-131 tositumomab is a well tolerated and effective therapy for recurrent low-grade and transformed low-grade non-Hodgkin lymphoma (NHL). Hematologic reserve after radioimmunotherapy (RIT) is an important consideration when subsequent therapy is required.


One hundred fifty-five patients who received treatment with I-131 tositumomab were assessed, and 68 patients had progressive disease after RIT. The median age (n = 68 patients) was 59 years (range,18–82 yrs), and patients received a median of 2 pre-RIT regimens (range,1–8 regimens), including 66% who received anthracycline, 19% who received platinum, and 50% who received fludarabine.


The median time to disease progression (among progressors) was 168 days (range, 19–771 days). At the time they developed recurrent disease, patients had median white blood cell count (WBC) of 4.9 K cells/μL (range, 1.1–21.4 K cells/μL), a median absolute neutrophil count (ANC) of 3.25 K cells/μL (range, 0.59–8.20 K cells/μL), a median platelet count of 130 K cells/μL (range, 9–440 K cells/μL), and there was no significant difference between pre-RIT and recurrence values except for the platelet count (P < 0.05). No patient demonstrated a WBC < 1.0 K cells/μL or an ANC < 0.5 K cells/μL, although 1 patient had a platelet count < 10 K cells/μL. Twenty-four patients subsequently received no further chemotherapy; and, in 21 patients (88%), hematologic parameters appeared to allow subsequent chemotherapy if necessary (blood counts: National Cancer Institute Grade 0–2). Among 44 patients (65%) who received further chemotherapy (median, 2 regimens; range, 1–4 regimens), 19 patients (43%) were treated with anthracyclines, 17 patients (39%) were treated with platinum, 10 patients (23%) were treated with fludarabine, and 13 patients (30%) underwent stem cell transplantation. Disease improvement occurred in most patients, although 18 patients died (40%) after further chemotherapy, predominantly from refractory lymphoma.


Most patients with progressive disease after treatment with iodine I-131 tositumomab were able to receive subsequent therapy, including cytotoxic chemotherapy and stem cell transplantation. Cancer 2006. © 2005 American Cancer Society.