Low-dose, fractionated radioimmunotherapy for B-cell malignancies using 131I-Lym-1 antibody.
OBJECTIVE
This trial was conducted to assess the toxicity and efficacy of 131I-Lym-1 in patients with either malignant B-cell non-Hodgkin's lymphoma (NHL) or chronic lymphocytic leukemia (CLL) using low-dose, fractionated radioimmunotherapy (RIT).


METHODS
Thirty adult patients who had advanced B-cell malignancies (25 NHL and 5 CLL) had progressed despite standard therapy; 12 patients entered the trial with Karnofsky performance status (KPS) of equal to or greater than 60. Patients were treated with a series of intravenous doses of 131I-Lym-1 with a goal of reaching a cumulative dose in each patient of at least 300 mCi. All patients were Lym-1 reactive. Clinical responses and immediate toxicity were evaluable in all 30 patients and delayed toxicity in 26.


RESULTS
Toxicity to Lym-1 antibody occurred with 28% of the 176 doses and was transient. Human antimouse antibodies (HAMA) were generated in 30% after a mean of 4 doses, but interrupted therapy in only 10% of the patients. Thrombocytopenia was dose-limiting; there were no deaths due to toxicity. Tumor regression occurred in 25 (83%) of the patients and was great enough, and durable enough, in 17 (57%) to qualify them as responders; 13 NHL patients and 4 CLL patients. Advanced disease often interrupted therapy prematurely. However, 18 patients received at least 180 mCi of 131I-Lym-1; 17 (94%) of these responded to the therapy.


CONCLUSIONS
Although advanced disease often interrupted therapy prematurely, the results from 131I-Lym-1 therapy are clearly promising and warrant additional trials.
DeNardo
G L
GL
University of California Davis Medical Center, Sacramento 95816, USA.
DeNardo
S J
SJ
Lamborn
K R
KR
Goldstein
D S
DS
Levy
N B
NB
Lewis
J P
JP
O'Grady
L F
LF
Raventos
A
A
Kroger
L A
LA
Macey
D J
DJ
McGahan
J P
JP
Mills
S L
SL
Shen
S
S
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000009:adverse effects* / Q000627:therapeutic use; D058846:Antibodies, Monoclonal, Murine-Derived; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000473:pathology / Q000532:radiotherapy*; D016393:Lymphoma, B-Cell / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016499:Radioimmunotherapy / Q000009:adverse effects; D019275:Radiopharmaceuticals / Q000009:adverse effects / Q000627:therapeutic use*; D015899:Tomography, Emission-Computed, Single-Photon
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D007457:Iodine Radioisotopes; C410509:Lym-1 monoclonal antibody; D019275:Radiopharmaceuticals