Chemical castration of melanoma patients does not increase the frequency of tumor-specific CD4 and CD8 T cells after peptide vaccination.

Peptide vaccination against tumor-associated antigens remains one of the most common methods of immunization in cancer vaccine clinical trials. Although peptide vaccination has been reported to increase circulating antigen-specific T-cells, they have had limited clinical efficacy and there is a necessity to increase their capacity to generate strong antitumor responses. We sought to improve the clinical efficacy of peptide-based vaccines in cancer immunotherapy of metastatic melanoma using a LHRH agonist (leuprolide) as adjuvant. Seventy HLA-A*0201 stage IIb-IV melanoma patients were vaccinated with class I HLA-A*0201-restricted gp100209-2M peptide and stratified for HLA-DP4 restriction. HLA-DP4 patients were also vaccinated with class II HLA-DP4-restricted MAGE-3243-258 peptide. Patients from both groups were randomized to receive 2 doses of leuprolide or not. Here we report the increase in PBMC TREC levels at week 24 after peptide vaccination, which was independent of the leuprolide treatment. This change was mirrored by a small increase in the TREC-enriched CD8CD45RAROCD27CD103, but not the TREC-enriched CD4CD45RAROCD31 T-cell population. Serum concentration of 2 important factors for thymopoiesis was measured: insulin growth factor 1 (IGF-1) levels were not changed, whereas a moderate increase in IL-7 levels was noted in the sera of all patients 6 weeks after vaccination. Increased expression of CD127 (IL-7 receptor-α) at week 24, compared with baseline, was only seen in the CD8CD45RAROCD27CD103 T-cell population. Our results suggest that leuprolide has no effect on thymic output when used as peptide vaccine adjuvant, but IFA-based peptide vaccination may unexpectedly affect the thymus by increasing thymic output of new T cells.

Specific lymphocyte subsets predict response to adoptive cell therapy using expanded autologous tumor-infiltrating lymphocytes in metastatic melanoma patients.

PURPOSE: Adoptive cell therapy (ACT) using autologous tumor-infiltrating lymphocytes (TIL) is a promising treatment for metastatic melanoma unresponsive to conventional therapies. We report here on the results of an ongoing phase II clinical trial testing the efficacy of ACT using TIL in patients with metastatic melanoma and the association of specific patient clinical characteristics and the phenotypic attributes of the infused TIL with clinical response. EXPERIMENTAL DESIGN: Altogether, 31 transiently lymphodepleted patients were treated with their expanded TIL, followed by two cycles of high-dose interleukin (IL)-2 therapy. The effects of patient clinical features and the phenotypes of the T cells infused on the clinical response were determined. RESULTS: Overall, 15 of 31 (48.4%) patients had an objective clinical response using immune-related response criteria (irRC) with 2 patients (6.5%) having a complete response. Progression-free survival of more than 12 months was observed for 9 of 15 (60%) of the responding patients. Factors significantly associated with the objective tumor regression included a higher number of TIL infused, a higher proportion of CD8(+) T cells in the infusion product, a more differentiated effector phenotype of the CD8(+) population, and a higher frequency of CD8(+) T cells coexpressing the negative costimulation molecule "B- and T-lymphocyte attenuator" (BTLA). No significant difference in the telomere lengths of TIL between responders and nonresponders was identified. CONCLUSION: These results indicate that the immunotherapy with expanded autologous TIL is capable of achieving durable clinical responses in patients with metastatic melanoma and that CD8(+) T cells in the infused TIL, particularly differentiated effectors cells and cells expressing BTLA, are associated with tumor regression.

Impact of clinical and pathologic features on tumor-infiltrating lymphocyte expansion from surgically excised melanoma metastases for adoptive T-cell therapy.

PURPOSE: Clinical trials on adoptive T-cell therapy (ACT) using expanded tumor-infiltrating lymphocytes (TIL) have shown response rates of over 50% in refractory melanoma. However, little is known how clinical and pathologic features impact TIL outgrowth isolated from metastatic melanoma tumors. EXPERIMENTAL DESIGN: We analyzed the impact of clinical and pathologic features on initial TIL outgrowth in 226 consecutive patients undergoing tumor resection. Successful initial TIL outgrowth was defined as ≥40 million viable lymphocytes harvested from all tumor fragments in a 5-week culture. To normalize for the different size of resected tumors and thus available tumor fragments, we divided the number of expanded TIL by the starting number of tumor fragments (TIL/fragment). RESULTS: Overall, initial TIL outgrowth was successful in 62% of patients, with patients ≤30 years of age (94%; P = 0.01) and female patients (71% vs. 57% for males; P = 0.04) having the highest rate of success. Systemic therapy 30 days before tumor harvest negatively impacted initial TIL outgrowth compared to patients who never received systemic therapy (47% vs. 71%, P = 0.02). Biochemotherapy within 0 to 60 days of tumor harvest negatively impacted the initial TIL outgrowth with a success rate of only 16% (P < 0.0001). CONCLUSION: Parameters such as age, sex, and the type and timing of prior systemic therapy significantly affect the success rate of the initial TIL outgrowth from tumor fragments for ACT; these parameters may be helpful in selecting patients for melanoma ACT.