Serum TA90 antigen-antibody complex as a surrogate marker for the efficacy of a polyvalent allogeneic whole-cell vaccine (CancerVax) in melanoma.
BACKGROUND
TA90 is a tumor-associated 90-kD glycoprotein antigen expressed on most melanoma cells, including those of CancerVax, a polyvalent allogeneic whole-cell vaccine. Previous studies have shown that a TA90 antigen-antibody immune complex (IC) in the serum of patients with melanoma is a marker of subclinical tumor burden and a strong prognostic factor. We hypothesized that the induction of TA90-IC during postoperative adjuvant CancerVax therapy might indicate vaccine-mediated immune destruction of subclinical melanoma cells with release of TA90, and thereby serve as a surrogate marker of vaccine efficacy.


METHODS
From 1993 to 1997, 219 melanoma patients were enrolled in a prospective phase II trial of CancerVax plus bacille Calmette-Guerin (BCG) after complete tumor resection. Coded serum samples were prospectively collected and analyzed for TA90-IC before and 2, 4, 8, 12, and 16 weeks after initiation of CancerVax therapy. TA90-IC seroconverters were those patients whose negative TA90-IC values (< .410) became positive (> or = .410) after initiation of CancerVax treatment.


RESULTS
Before CancerVax therapy, 51 patients had positive TA90-IC values and 168 patients had negative TA90-IC values. During CancerVax treatment, all 51 positive patients remained positive, 79 (47%) negative patients seroconverted to positive, and 89 (53%) negative patients remained negative. Seroconverters had higher 2-year rates of disease-free survival (59% vs. 32%; P < .006) and overall survival (78% vs. 63%; P < .02) than did patients whose TA90-IC values remained positive.


CONCLUSIONS
CancerVax induces TA90-IC in melanoma patients with subclinical disease. TA90-IC seroconverted patients have significantly improved disease-free and overall survival compared with TA90-IC positive patients. TA90-IC is an important prognostic factor that can serve as a surrogate marker for the clinical efficacy of CancerVax.
Tsioulias
G J
GJ
Roy E. Coats Research Laboratories and Sonya Valley Ghidossi Vaccine Laboratory, Saint John's Health Center, Santa Monica, California 90404-2302, USA.
Gupta
R K
RK
Tisman
G
G
Hsueh
E C
EC
Essner
R
R
Wanek
L A
LA
Morton
D L
DL
D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002140:California / Q000453:epidemiology; D019496:Cancer Vaccines; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D015996:Survival Rate
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D019496:Cancer Vaccines; C113885:TA90 immune complex