Treatment of human lung carcinoma xenografts with a combination of 131I-labelled monoclonal antibody Po66 and doxorubicin.
Po66, a mouse monoclonal antibody, is directed against an intracytoplasmic antigen present in human lung squamous cell carcinoma cells. In previous work it was found that the co-administration of 125I-radiolabelled Po66 and doxorubicin strongly enhanced the uptake of radioactivity by the tumour. The present-work was designed to evaluate, in a tumour-bearing mouse model of lung carcinoma, the ability of 131I-labelled Po66 to retard tumour growth when injected alone, or in combination with doxorubicin (8 mg kg-1 at 1-week intervals). A single dose of 550 microCi 131I-Po66 alone had no effect on tumour growth, whereas three fractionated doses of 250 microCi 131I-Po66 decreased it over two doubling times from 14.5 +/- 1.5 days for untreated control mice to 24.8 +/- 2.7 days. Mice treated with doxorubicin alone had a double tumour doubling time of 22.6 +/- 4.9 days, compared to 35.2 +/- 2.9 days (1.55-fold increase) in mice treated with doxorubicin and a single dose of 550 microCi 131I-Po66. Doxorubicin combined with three fractionated doses of 250 microCi 131I-Po66 provoked a twofold decrease in tumour growth compared to mice treated with doxorubicin alone. The administration of fractionated doses of 131I-Po66 simultaneously with doxorubicin resulted in a highly delayed mortality, which was not observed when 131I-Po66 was administered after doxorubicin. Thus, in a non-small-cell lung tumour model, a 131I-radiolabelled monoclonal antibody, directed against an intracellular antigen, significantly potentiated the effect of chemotherapy. Such a therapeutic approach could be used as an adjuvant therapy and improve the effect of chemotherapy on distant small metastases.
Desrues
B
B
Centre Hospitalier Regional et Universitaire, Hôpital Pontchaillou, Rennes, France.
Brichory
F
F
Léna
H
H
Bourguet
P
P
Delaval
P
P
Toujas
L
L
Dazord
L
L
D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D004317:Doxorubicin / Q000008:administration & dosage*; D006801:Humans; D000922:Immunotoxins / Q000008:administration & dosage*; D007457:Iodine Radioisotopes / Q000008:administration & dosage*; D008175:Lung Neoplasms / Q000628:therapy*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation
D000911:Antibodies, Monoclonal; D000922:Immunotoxins; D007457:Iodine Radioisotopes; D004317:Doxorubicin