Lack of efficacy of two consecutive treatments of radioimmunotherapy with 131I-cG250 in patients with metastasized clear cell renal cell carcinoma.
OBJECTIVE
A previous activity dose-escalation study using 131I-labeled chimeric monoclonal antibody cG250 in patients with progressive metastatic renal cell carcinoma (RCC) resulted in occasional therapeutic responses. The present study was designed to determine the safety and therapeutic efficacy of two sequential high-dose treatments with 131I-cG250.


METHODS
Patients (n = 29) with progressive metastatic RCC received a low dose of (131)I-cG250 for assessment of preferential targeting of metastatic lesions, followed by the first radioimmunotherapy (RIT) with 2220 MBq/m2 131I-cG250 (n = 27) 1 week later. If no grade 4 hematologic toxicity was observed, a second low-dose 131I-cG250 (n = 20) was given 3 months later. When blood clearance was not accelerated, a second RIT of 131I-cG250 was administered at an activity-dose of 1110 MBq/m2 (n = 3) or 1665 MBq/m2 (n = 16). Patients were monitored weekly for toxicity, and tumor size was evaluated by computed tomography once every 3 months intervals.


RESULTS
The maximum-tolerated dose (MTD) of the second RIT was 1,665 MBq/m2 because of dose-limiting hematological toxicity. Based on an intention-to-treat analysis, after two RIT treatments, the disease stabilized in five of 29 patients, whereas it remained progressive in 14 of 29 patients. Two patients received no RIT, and eight of 29 received only one 131I-cG250 RIT because of grade 4 hematologic toxicity, formation of human antichimeric antibodies, or disease progression.


CONCLUSIONS
In patients with progressive end-stage RCC, the MTD of the second treatment was 75% of the MTD of the first RIT. In the majority of patients, two cycles of 131I-cG250 could be safely administered without severe toxicity. No objective responses were observed, but occasionally two RIT doses resulted in stabilization of previously progressive disease.
Brouwers
Adrienne H
AH
Department of Nuclear Medicine, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands. a.h.brouwers@nucl.umcg.nl
Mulders
Peter F A
PF
de Mulder
Pieter H M
PH
van den Broek
Wim J M
WJ
Buijs
Wilhelmina C A M
WC
Mala
Carola
C
Joosten
Frank B M
FB
Oosterwijk
Egbert
E
Boerman
Otto C
OC
Corstens
Frans H M
FH
Oyen
Wim J G
WJ
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics / Q000627:therapeutic use*; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging / Q000401:mortality / Q000532:radiotherapy* / Q000556:secondary*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use; D007553:Isotope Labeling; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D008297:Male; D020714:Maximum Tolerated Dose; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011336:Probability; D016499:Radioimmunotherapy / Q000379:methods*; D011877:Radionuclide Imaging; D018570:Risk Assessment; D016019:Survival Analysis; D017211:Treatment Failure
D000911:Antibodies, Monoclonal; D007457:Iodine Radioisotopes