Integrated NY-ESO-1 antibody and CD8+ T-cell responses correlate with clinical benefit in advanced melanoma patients treated with ipilimumab

Abstract

Ipilimumab, a monoclonal antibody against cytotoxic T lymphocyte antigen 4 (CTLA-4), has been shown to improve survival in patients with advanced metastatic melanoma. It also enhances immunity to NY-ESO-1, a cancer/testis antigen expressed in a subset of patients with melanoma. To characterize the association between immune response and clinical outcome, we first analyzed NY-ESO-1 serum antibody by ELISA in 144 ipilimumab-treated patients with melanoma and found 22 of 140 (16%) seropositive at baseline and 31 of 144 (22%) seropositive following treatment. These NY-ESO-1-seropositive patients had a greater likelihood of experiencing clinical benefit 24 wk after ipilimumab treatment than NY-ESO-1-seronegative patients (P = 0.02, relative risk = 1.8, two-tailed Fisher test). To understand why some patients with NY-ESO-1 antibody failed to experience clinical benefit, we analyzed NY-ESO-1-specific CD4(+) and CD8(+) T-cell responses by intracellular multicytokine staining in 20 NY-ESO-1-seropositive patients and found a surprising dissociation between NY-ESO-1 antibody and CD8 responses in some patients. NY-ESO-1-seropositive patients with associated CD8(+) T cells experienced more frequent clinical benefit (10 of 13; 77%) than those with undetectable CD8(+) T-cell response (one of seven; 14%; P = 0.02; relative risk = 5.4, two-tailed Fisher test), as well as a significant survival advantage (P = 0.01; hazard ratio = 0.2, time-dependent Cox model). Together, our data suggest that integrated NY-ESO-1 immune responses may have predictive value for ipilimumab treatment and argue for prospective studies in patients with established NY-ESO-1 immunity. The current findings provide a strong rationale for the clinical use of modulators of immunosuppression with concurrent approaches to favor tumor antigen-specific immune responses, such as vaccines or adoptive transfer, in patients with cancer.

Fig. 1.

Titers in NY-ESO-1–seropositive patients from MSKCC. Reciprocal antibody titers to NY-ESO-1 throughout CTLA-4 blockade treatment in patients experiencing clinical benefit (closed symbols, Left; n = 11) or no clinical benefit (open symbols, Right; n = 10) among 99 patients treated with ipilimumab at MSKCC. The remaining 78 patients did not show significant Ab reactivity against NY-ESO-1 at any time point tested and were considered seronegative (i.e., titers <100). Each symbol represents a patient (Right) at baseline, week 7, and week 12 or 24.

Fig. 2.

NY-ESO-1–specific CD4⁺ and CD8⁺ T-cell responses were induced after CTLA-4 blockade. Representative dot plots from four patients (IMF-56, 09–079-10, IMF-28, and 09–079-7) with or without NY-ESO-1 overlapping peptide stimulation. Patient IMF-56 had both NY-ESO-1–specific CD4⁺ and CD8⁺ T-cell response; patients 09–079-10 and IMF-28 had only NY-ESO-1–specific CD8⁺ T-cell response or CD4⁺ T-cell response, respectively; patient 09–079-7 had neither NY-ESO-1–specific CD4⁺ nor CD8⁺ T-cell response.

Fig. 3.

Four types of NY-ESO-1 immunity integration were detected during ipilimumab treatment. (A) NY-ESO-1–specific CD4⁺ T-cell response before and after CTLA-4 blockade. (B) NY-ESO-1–specific CD8⁺ T-cell response before and after CTLA-4 blockade. Category I, 11 of 20 patients had NY-ESO-1–specific CD4⁺ and CD8⁺ T-cell response; category II, two of 20 patients had CD8 T-cell response; category III, five of 20 patients had CD4⁺ T-cell response; and category IV, two of 20 patients had neither CD4⁺ nor CD8 T-cell response.

Fig. 4.

NY-ESO-1 antigen-specific CD8⁺ T-cell responses are associated with clinical benefit. Maximal percentage of NY-ESO-1–specific CD4⁺ IFN-γ⁺ and CD8⁺IFN-γ⁺ T cell at any time point during CTLA-4 blockade treatment in NY-ESO-1–seropositive patients treated with ipilimumab at MSKCC who experienced clinical benefit (closed symbols; n = 11) or no clinical benefit (open symbols; n = 9). Responses were considered positive if at least 0.1%. Each symbol represents a patient (Right). Although the frequency of CD4⁺IFN-γ⁺ T-cell responses did not significantly differ in patients with or without clinical benefit (P = 0.285), CD8⁺IFN-γ⁺ T-cell response were significantly more frequent in patients who experienced clinical benefit (10 of 11) compared with patients who did not experience clinical benefit [three of nine; P = 0.017, RR = 5.4 (0.9–33.9), two-tailed Fisher test].