Faculty Bibliography

Immune responses have been elicited by a variety of cancer vaccines, but seldom induce regressions of established cancers in humans. As a novel therapeutic immunization strategy, we tested the hypothesis that multiple cytokines/chemokines secreted early in secondary responses ex-vivo might mimic the secretory environment guiding new immune responses. The early development of immune responses is regulated by multiple cytokines/chemokines acting together, which at physiologic concentrations act locally in concert with antigen to have non-specific effects on adjacent cells, including the maturation of dendritic cells, homing and retention of T cells at the site of antigen, and the differentiation and expansion of T cell clones with appropriate receptors. We postulated that repeated injections into a metastasis of an exogenous chemokine/cytokine mixture might establish the environment of an immune response and allow circulating T cell clones to self- select for mutant neo-epitopes in the tumor and generate systemic immune responses. To test this idea we injected some metastases in patients with multiple cutaneous melanoma nodules while never injecting other control metastases in the same patient. New immune responses were identified by the development of dense lymphocytic infiltrates in never-injected metastases, and the frequent complete regression of never-injected metastases, a surprising observation. 70% of subjects developed dense infiltrates of cytotoxic CD8 cells in the center and margin of never-injected metastases; 38% of subjects had complete and often durable regressions of all metastases, without the use of check-point inhibitors, suggesting that, as a proof-of-principle, an immunization strategy can control advanced human metastatic melanoma.

PURPOSE: Melanoma cells can be found in the circulation of patients with melanoma. The following study was conducted to examine whether changes in their presence could provide an early marker of response to therapy. EXPERIMENTAL DESIGN: We measured the presence of several markers of melanoma cells in the peripheral blood of 118 patients with resected stage IIb, III, or IV melanoma before and after immunotherapy with a polyvalent, shed antigen, melanoma vaccine using reverse transcription-PCR assays for tyrosinase, gp100, MART-1, and MAGE-3. Assays were conducted at baseline and after 3, 5, and 11 months of therapy. RESULTS: Overall, 47% of patients were positive for at least one marker during the study. Before vaccine treatment, circulating melanoma cell markers were present in 23% of patients. After 5 and 7 months of vaccine therapy, the proportion of patients with circulating markers decreased by 27% and 55%, respectively (P for trend = 0.02). The recurrence-free survival of patients whose melanoma cell markers disappeared during vaccine treatment was significantly longer than that of patients in whom they increased, i.e., the percentage of patients who were recurrence free at 1 year was 80% versus 58% (P = 0.03). CONCLUSIONS: Therapy with a polyvalent melanoma vaccine was associated with clearance of melanoma cell markers from the circulation, and the clearance was associated with an improved prognosis. These findings suggest that the sequential assay of tumor cells in the circulation by reverse transcription-PCR may provide an early indication of the effectiveness of cancer therapy

PURPOSE: Vaccine-induced antitumor CD8+ T-cell responses are believed to play an important role in increasing resistance to melanoma. The following study was conducted to examine whether these responses are associated with improved clinical outcome in melanoma vaccine-treated patients. EXPERIMENTAL DESIGN: We measured CD8+ T-cell responses to gp100, MART-1, MAGE-3, and tyrosinase by enzyme-linked immunospot assay in peripheral blood of 131 HLA-A*01- or HLA-A*02-positive melanoma patients before and after immunization to a polyvalent, shed antigen, melanoma vaccine, and correlated the results with clinical outcome. RESULTS: Fifty-six percent of patients had a vaccine-induced CD8+ T-cell response to at least one of the four antigens. Recurrences were significantly reduced in patients with vaccine-induced responses to MAGE-3 (hazard ratio, 0.42; 95% confidence interval, 0.18-0.99; P = 0.03) by the Cox proportional hazard model but were unrelated to responses to the other three antigens. Patients with a preexisting response to any of the four antigens were significantly more likely to have a further vaccine-boosted response to that same antigen (P < 0.0001-0.036). CONCLUSIONS: There was a correlation between vaccine-induced CD8+ T-cell responses to melanoma-associated antigens and improved clinical outcome, but the correlation depended on the antigen against which the response is directed. The only significant correlation was with responses to MAGE-3