Purpose: Adoptive cell therapy with autologous tumor-infiltrating lymphocytes (TIL) has shown promising results in metastatic melanoma patients. Although objective response rates of over 50% have been reported, disadvantages of this approach are the labor-intensive TIL production and a very high drop-out rate of enrolled patients, limiting its widespread applicability.Previous studies showed a clear correlation between short TIL culture periods and clinical response. Therefore, we used a new TIL production technique using unselected, minimally cultured, bulk TIL (Young-TIL). The use of Young-TIL is not restricted to human leukocyte antigen (HLA)-A2 patients.The purpose of this study is to explore the efficacy and toxicity of adoptively transferred Young-TIL following lympho-depleting chemotherapy in metastatic melanoma patients, refractory to interleukin-2 and chemotherapy.Experimental Design: Young-TIL cultures for 90% of the patients were successfully generated, enabling the treatment of most enrolled patients. We report here the results of 20 evaluated patients.Results: Fifty percent of the patients achieved an objective clinical response according to the Response Evaluation Criteria in Solid Tumors, including two ongoing complete remissions (20+, 4+ months) and eight partial responses (progression-free survival: 18+, 13+, 10+, 9, 6+, 4, 3+, and 3 months). All responders are currently alive. Four additional patients showed disease stabilization. Side effects were transient and manageable.Conclusion: We showed that lympho-depleting chemotherapy followed by transfer of short-term cultured TIL can mediate tumor regression in 50% of metastatic melanoma with manageable toxicity. The convincing clinical results combined with the simplification of the process may thus have a major effect on cell therapy of cancer. Clin Cancer Res; 16(9); 2646-55. ©2010 AACR.

Treatment of metastatic melanoma patients with adoptively transferred tumor infiltrating lymphocytes (TIL) has developed into an effective therapy. Various studies reported objective responses of 50% and more. The use of unselected, minimally cultured, bulk TIL (Young-TIL) has simplified the TIL production process and may therefore, allow the accessibility of this approach to cancer centers worldwide. This article describes the precise process leading to the large-scale production of Young-TIL for therapy. We have enrolled 55 melanoma patients and optimized their Young-TIL generation process. Young-TIL cultures were successfully established for 51 of 55 (93%) patients in 16.7 ± 5.5 days. In a large-scale expansion procedure Young-TIL of 32 patients were further expanded to treatment levels, resulting in a final number of 4.5 x 10¹⁰ ± 2.0 x 10¹⁰ TIL. Fifteen of 31 (48%) patients, who were evaluated, achieved a clinical response, including 4 complete and 11 partial responses. We confirmed the significant correlation between short culture duration, high number of infused cells, and tumor regression. A high percentage of CD8 T cells in the infusion product was beneficial to achieve an objective response. All responding patients were treated with Young-TIL cultures established in < 20 days. In summary, we describe here an efficient and reliable method to generate Young-TIL for adoptive transfer therapy, which may easily be adopted by other cancer centers and can lead to objective responses in 50% of refractory melanoma patients. In the future this approach may be used also in other types of malignancies.

CEACAM1 (biliary glycoprotein-1, CD66a) was reported as a strong clinical predictor of poor prognosis in melanoma. We have previously identified CEACAM1 as a tumor escape mechanism from cytotoxic lymphocytes. Here, we present substantial evidence in vitro and in vivo that blocking of CEACAM1 function with a novel monoclonal antibody (MRG1) is a promising strategy for cancer immunotherapy. MRG1, a murine IgG1 monoclonal antibody, was raised against human CEACAM1. It recognizes the CEACAM1-specific N-domain with high affinity (K D $ 2 nmol/L). Furthermore, MRG1 is a potent inhibitor of CEACAM1 homophilic binding and does not induce any agonistic effect. We show using cytotoxicity assays that MRG1 renders multiple melanoma cell lines more vulnerable to T cells in a dose-dependent manner, only following antigen-restricted recognition. Accordingly, MRG1 significantly enhances the antitumor effect of adoptively transferred, melanoma-reactive human lymphocytes using human melanoma xenograft models in severe combined immunodeficient/nonobese diabetic (SCID/NOD) mice. A significant antibody-dependent cell cytotoxicity response was excluded. It is shown that MRG1 reaches the tumor and is cleared within a week. Importantly, approximately 90% of melanoma specimens are CEACAM1 þ , implying that the majority of patients with melanoma could be amenable to MRG1-based therapy. Normal human tissue microarray displays limited binding to luminal epithelial cells on some secretory ducts, which was weaker than the broad normal cell binding of other anticancer antibodies in clinical use. Importantly, MRG1 does not directly affect CEACAM1 þ cells. CEACAM1 blockade is different from other immunomodulatory approaches, as MRG1 targets inhibitory interactions between tumor cells and late effector lymphocytes, which is thus a more specific and compartmentalized immune stimulation with potentially superior safety profile.