Presence of Specific CTCs Predicts Survival in Advanced Melanoma
“Our findings support the therapeutic relevance of Melan-A and NY-ESO-1 as targets for immunotherapy,” the investigators noted.
The multinational study analyzed prognostic relevance of circulating T cells responding to NY-ESO-1, Melan-A, MAGE-3, and survivin in patients with melanoma with distant metastasis. Cohort A included 84 patients with follow-up after analysis; cohort B, 18 long-term survivors with an extraordinarily favorable course of disease before analysis, defined as >24 months survival after first occurrence of distant metastases; and 14 healthy controls. Intracellular cytokine staining after in vitro stimulation was used to characterize circulating antigen-reactive T cells.
“In cohort A patients, the presence of T cells responding to peptides from NY-ESO-1, Melan-A, or MAGE-3 and the M category according to the American Joint Committee on Cancer classification were significantly associated with survival,” the investigators wrote. T cells responding to NY-ESO-1 (HR=0.29; P=0.001) and Melan-A (HR=0.18; P<0.001) peptide remained independent prognostic factors in Cox regression analysis and were superior to the M category in predicting outcome.
For patients possessing T cells responding to NY-ESO-1, Melan-A, or both, median survival was 21 months vs. 6 months for all others. “NY-ESO-1–responsive T cells were detected in 70% of cohort A patients surviving >18 months and in 50% of cohort B patients,” they found. Melan-A responses were found in 42% of patients in cohort A and 47% of cohort B; however, for those who died within 6 months, the proportion was only 22% for NY-ESO-1 and 23% for Melan-A.