Montane, Heather N

Background/Objectives: Tumor-infiltrating lymphocyte (TIL) therapy is an important option for patients with metastatic melanoma progressing after standard systemic therapy, but real-world data on treatment delivery, toxicity monitoring, and immune recovery remain limited. We evaluated clinical outcomes, treatment tolerance, immune reconstitution, and cardiac biomarker dynamics across three Mayo Clinic sites. Methods: We retrospectively analyzed adults with metastatic melanoma who received lymphodepleting chemotherapy followed by TIL infusion and high-dose interleukin-2 (IL-2) between April 2024 and December 2025. Clinical outcomes, treatment delivery, and adverse events were assessed. Longitudinal immune monitoring included CD4 and CD8 T-cell counts, CD4:CD8 ratio, and immunoglobulin G (IgG) at baseline and follow-up. In a prespecified cardiac sub-cohort, high-sensitivity troponin (hs-Tn) was measured during IL-2 administration to evaluate associations with cardiac events and IL-2 interruption. Results: Thirty-six patients underwent TIL infusion. The objective response rate was 50.0%, including complete responses in 13.9%, and the disease control rate was 72.2%. Median progression-free survival was 3.61 months, and median overall survival was 12.94 months. M1d disease was associated with inferior overall survival on univariable analysis (HR 6.55, 95% CI 2.03–21.17; p = 0.002), with attenuation after multivariable adjustment. Receipt of ≥3 IL-2 doses was associated with longer overall survival on univariable analysis (HR 0.20, 95% CI 0.06–0.64; p = 0.007), but this association also attenuated after adjustment. Longitudinal immune monitoring demonstrated persistent CD4 lymphopenia through 6 months, sustained inversion of the CD4:CD8 ratio, and declining IgG at months 3 and 6. In the cardiac sub-cohort (24 patients; 87 IL-2 doses), post-dose hs-Tn ≥15 ng/L was associated with clinically significant cardiac events (OR 9.6, 95% CI 1.5–60.6; p = 0.016) and IL-2 interruption (OR 3.4, 95% CI 1.1–10.7; p = 0.036). For cardiac events, hs-Tn ≥15 ng/L had 100% sensitivity and 100% negative predictive value. Conclusions: In routine practice, TIL therapy was feasible and active in metastatic melanoma. M1d disease identified a subgroup with poor survival, peri-dose hs-Tn showed promise as a tool to support safer IL-2 delivery, and prolonged CD4 suppression with IgG decline suggests that recovery after TIL therapy extends beyond initial hematologic reconstitution. These findings support prospective validation of biomarker-guided IL-2 monitoring and extended post-treatment immune surveillance.

Background Neoadjuvant treatment has become standard for patients with high-risk operable stage III melanoma, but the optimal regimen is unknown. Targeted therapy approaches yield high pathological response rates, while immunotherapy regimens show favorable recurrence-free survival (RFS). NeoACTIVATE was designed to address whether a neoadjuvant combination of both targeted therapy and immunotherapy might leverage the benefits of each. Methods We tested neoadjuvant treatment with 12 weeks of vemurafenib, cobimetinib, and atezolizumab for patients with BRAF-mutated (BRAFm) melanoma (cohort A) and cobimetinib and atezolizumab for patients with BRAF-wild-type (BRAFwt) melanoma (cohort B), regimens which we have shown generate a substantial major pathological response. After therapeutic lymph node dissection, patients received 24 weeks of adjuvant atezolizumab. Here, we report survival outcomes and their association with biomarkers assayed among the gut microbiome and peripheral blood immune subsets. Results With 49 months median follow-up, the median RFS was not reached for cohort A and was 40.8 months for cohort B. At 24 months after operation, 2 of 14 cohort A patients and 4 of 13 cohort B patients had experienced distant relapse. Key findings from correlative analyses included diversity, taxonomic and functional metagenomic gut microbiome signals associated with distant metastasis-free survival at 2 years. Notably, we observed a strong correlation between low microbial arginine biosynthesis (required for T-cell activation and effector function) and early distant recurrence (p=0.0005), which correlated with taxonomic differential abundance findings. Peripheral blood immune monitoring revealed increased double-positive (CD4+CD8+) T cells in patients with early recurrence. Conclusions Neoadjuvant treatment with cobimetinib and atezolizumab±vemurafenib was associated with a low rate of distant metastasis in patients with high-risk stage III melanoma. Freedom from early distant metastasis was highly associated with taxonomic differences in gut microbiome structure and with functional pathway alterations known to modulate T cell immunity. Identification of predictive biomarkers will permit optimization of neoadjuvant therapy regimens for individual patients. Trial registration number NCT03554083.