A phase II study of G17DT in gastric carcinoma.
OBJECTIVE
G17DT is a gastrin immunogen, raising antibodies that blockade gastrin-stimulated growth. The aim of the study was to characterise antibody response and assess safety and tolerability of G17DT given to patients with gastric cancer.


METHODS
G17DT was administered to 52 patients with gastric adenocarcinoma at weeks 0, 2 and 6 by intramuscular injection at doses of 10, 100 and 250 microg. Antibody levels were measured by an ELISA assay. A radioligand displacement assay determined the ability of G17DT-immunised patients' sera to inhibit binding of 125IG17 to cholecystokinin (CCK)-2 receptors.


RESULTS
By week 12 of the study, 6/12 evaluable stage I-III patients achieved an antibody response in the 10 microg group, 7/11 in the 100 microg group, and 11/12 in the 250 microg group. Stage IV patients dosed at 250 microg achieved a similar response rate to stage I-III patients dosed at 10 or 100 microg. G17DT was well tolerated in 47/52 patients. Two patients suffered significant adverse reactions including injection site pain and abscess. G17DT antibodies displaced iodinated gastrin from CCK-2 receptors, with the level of displacement correlating with antibody titre.


CONCLUSIONS
G17DT immunisation is a well-tolerated method of raising functional antibodies to 17 amino acid gastrin forms in patients with gastric carcinomas.
Gilliam
A D
AD
Academic Unit of Cancer Studies, D Floor, West Block, Queen's Medical Centre, University Hospital, Nottingham NG7 2UH, UK.
Watson
S A
SA
Henwood
M
M
McKenzie
A J
AJ
Humphreys
J E
JE
Elder
J
J
Iftikhar
S Y
SY
Welch
N
N
Fielding
J
J
Broome
P
P
Michaeli
D
D
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000276:immunology* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000917:Antibody Formation / Q000187:drug effects*; D019496:Cancer Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D005755:Gastrins; D006801:Humans; D007106:Immune Sera / Q000187:drug effects / Q000276:immunology; D007117:Immunization, Secondary; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D043887:Receptor, Cholecystokinin B / Q000187:drug effects / Q000276:immunology; D013223:Statistics as Topic; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000276:immunology* / Q000473:pathology; D016896:Treatment Outcome
D019496:Cancer Vaccines; D005755:Gastrins; D007106:Immune Sera; D043887:Receptor, Cholecystokinin B; C482698:gastrin immunogen