Tositumomab and iodine I 131 tositumomab for recurrent indolent and transformed B-cell non-Hodgkin's lymphoma.
OBJECTIVE
An open-label phase II study was conducted at two centers to establish the efficacy and safety of tositumomab and iodine I 131 tositumomab at first or second recurrence of indolent or transformed indolent B-cell lymphoma.


METHODS
A single dosimetric dose was followed at 7 to 14 days by the patient-specific administered radioactivity required to deliver a total body dose of 0.75 Gy (reduced to 0.65 Gy for patients with platelets counts of 100 to 149 x 10(9)/L). Forty of 41 patients received both infusions.


RESULTS
Thirty-one of 41 patients (76%) responded, with 20 patients (49%) achieving either a complete (CR) or unconfirmed complete remission [CR(u)] and 11 patients (27%) achieving a partial remission. Response rates were similar in both indolent (76%) and transformed disease (71%). The overall median duration of remission was 1.3 years. The median duration of remission has not yet been reached for those patients who achieved a CR or CR(u). Eleven patients continue in CR or CR(u) between 2.6+ and 5.2+ years after therapy. Therapy was well tolerated; hematologic toxicity was the principal adverse event. Grade 3 or 4 anemia, neutropenia, and thrombocytopenia were observed in 5%, 45%, and 32% of patients, respectively. Secondary myelodysplasia has occurred in one patient. Four patients developed human antimouse antibodies after therapy. Five of 38 assessable patients have developed an elevated thyroid-stimulating hormone; treatment with thyroxine has been initiated in one patient.


CONCLUSIONS
High overall and CR rates were observed after a single dose of tositumomab and iodine I 131 tositumomab in this patient group. Toxicity was modest and easily managed.
Davies
A J
AJ
Cancer Research UK Medical Oncology Unit, Department of Medical Oncology, 45 Little Britain, St Bartholomew's Hospital, London EC1A 7BE, United Kingdom. Andrew.J.Davies@cancer.org.uk
Rohatiner
A Z S
AZ
Howell
S
S
Britton
K E
KE
Owens
S E
SE
Micallef
I N
IN
Deakin
D P
DP
Carrington
B M
BM
Lawrance
J A
JA
Vinnicombe
S
S
Mather
S J
SJ
Clayton
J
J
Foley
R
R
Jan
H
H
Kroll
S
S
Harris
M
M
Amess
J
J
Norton
A J
AJ
Lister
T A
TA
Radford
J A
JA
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D018951:Antigens, CD20 / Q000276:immunology*; D000970:Antineoplastic Agents; D006801:Humans; D018796:Immunoconjugates / Q000627:therapeutic use*; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D016393:Lymphoma, B-Cell / Q000188:drug therapy*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy; D016499:Radioimmunotherapy; D015996:Survival Rate
D000911:Antibodies, Monoclonal; D018951:Antigens, CD20; D000970:Antineoplastic Agents; D018796:Immunoconjugates; D007457:Iodine Radioisotopes; C119496:tositumomab I-131