Adoptive cell transfer in the treatment of metastatic melanoma

Adoptive T cell therapy combined with intralesional administrations of TG1042 (adenovirus expressing interferon-γ) in metastatic melanoma patients

Tumor immune escape has recently been shown to be related to the development of an immune tolerance state of the microenvironment. Cytokines activating the immune system such as IFN-γ can be used to reverse the immune escape and thus to potentiate the efficacy of immunotherapy. A clinical study was conducted in 18 stage IIIc/IV melanoma patients treated with tumor-infiltrating lymphocytes (TILs) in combination with intratumoral TG1042 injection (adenovirus expressing IFN-γ). The primary objective was to investigate the safety of treatment. Secondary objectives were to study the clinical response and translational research. The treatment was well tolerated. Among the 13 patients evaluable for tumor response, 38.5% had an overall objective response (OOR = CR + PR) and disease control rate (DCR = CR + PR + S) of 46%. The clinical response of the 37 targeted lesions led to an OOR of 51% and a DCR of 75%. Translational research on predictive markers did not significantly differ between responder and non-responder patients. However, specifically regarding injected lesions, the clinical response correlated with CD3-/CD56+ NK cells which could be activated by TG1042. Further larger studies of this combined immunotherapy are needed to confirm our findings. Intralesional TG1042 combined with antigen-selected TILs should be discussed.

Costimulation through the CD137/4-1BB pathway protects human melanoma tumor-infiltrating lymphocytes from activation-induced cell death and enhances antitumor effector function

Adoptive T-cell therapy (ACT) using expanded tumor-infiltrating lymphocytes (TIL) with high-dose interleukin-2 is a promising form of immunotherapy for stage IV melanoma having clinical response rates of 50% or more. One of the major problems preventing further success of this therapy is that the current protocols used to highly expand TIL for infusion drive CD8(+) T cells to differentiate into effector cells losing key costimulatory molecules such as CD28 and CD27. This has been associated with a lack of persistence in vivo for reasons not entirely clear. In this study, we demonstrate that while human melanoma CD8(+) TIL lost CD27 and CD28 expression during the rapid expansion for ACT, they gained expression of the alternative costimulatory molecule CD137/4-1BB, and to a lesser extent CD134/OX40. Postrapid expansion protocol (REP) TIL were found to be highly sensitive to activation-induced cell death when reactivated through the T-cell receptor with low levels of OKT3 antibody. However, coligation of 4-1BB using 2 different agonistic anti-4-1BB antibodies potently prevented activation-induced cell death of post-REP CD8(+) TIL, including those specific for melanoma antigen recognized by T cells, and facilitated even further cell expansion. This was correlated with increased levels of bcl-2 and bcl-xL together with decreased bim expression. 4-1BB costimulated post-REP TIL also expressed increased levels of the cytolytic granule proteins and exhibited enhanced cytotoxic T-cell activity against melanoma cells. Lastly, post-REP CD8(+) TIL were protected from cell death by anti-4-1BB ligation when exposed to human leukocyte antigen-matched melanoma cells. Our results indicate that 4-1BB costimulation may significantly improve TIL survival during melanoma ACT and boost antitumor cytolytic activity.

Harnessing the effect of adoptively transferred tumor-reactive T cells on endogenous (host-derived) antitumor immunity

Adoptive T cell transfer therapy, the ex vivo activation, expansion, and subsequent administration of tumor-reactive T cells, is already the most effective therapy against certain types of cancer. However, recent evidence in animal models and clinical trials suggests that host conditioning interventions tailored for some of the most aggressive and frequent epithelial cancers will be needed to maximize the benefit of this approach. Similarly, the subsets, stage of differentiation, and ex vivo expansion procedure of tumor-reactive T cells to be adoptively transferred influence their in vivo effectiveness and may need to be adapted for different types of cancer and host conditioning interventions. The effects of adoptively transferred tumor-reactive T cells on the mechanisms of endogenous (host-derived) antitumor immunity, and how to maximize their combined effects, are further discussed.

Treatment of cutaneous melanoma: current approaches and future prospects

Melanoma is the most aggressive and deadly type of skin cancer. Surgical resection with or without lymph node sampling is the standard of care for primary cutaneous melanoma. Adjuvant therapy decisions may be informed by careful consideration of prognostic factors. High-dose adjuvant interferon alpha-2b increases disease-free survival and may modestly improve overall survival. Less toxic alternatives for adjuvant therapy are currently under study. External beam radiation therapy is an option for nodal beds where the risk of local recurrence is very high. In-transit melanoma metastases may be treated locally with surgery, immunotherapy, radiation, or heated limb perfusion. For metastatic melanoma, the options include chemotherapy or immunotherapy; targeted anti-BRAF and anti-KIT therapy is under active investigation. Standard chemotherapy yields objective tumor responses in approximately 10%-20% of patients, and sustained remissions are uncommon. Immunotherapy with high-dose interleukin-2 yields objective tumor responses in a minority of patients; however, some of these responses may be durable. Identification of activating mutations of BRAF, NRAS, c-KIT, and GNAQ in distinct clinical subtypes of melanoma suggest that these are molecularly distinct. Emerging data from clinical trials suggest that substantial improvements in the standard of care for melanoma may be possible.

Treatment of cutaneous melanoma: current approaches and future prospects

Melanoma is the most aggressive and deadly type of skin cancer. Surgical resection with or without lymph node sampling is the standard of care for primary cutaneous melanoma. Adjuvant therapy decisions may be informed by careful consideration of prognostic factors. High-dose adjuvant interferon alpha-2b increases disease-free survival and may modestly improve overall survival. Less toxic alternatives for adjuvant therapy are currently under study. External beam radiation therapy is an option for nodal beds where the risk of local recurrence is very high. In-transit melanoma metastases may be treated locally with surgery, immunotherapy, radiation, or heated limb perfusion. For metastatic melanoma, the options include chemotherapy or immunotherapy; targeted anti-BRAF and anti-KIT therapy is under active investigation. Standard chemotherapy yields objective tumor responses in approximately 10%-20% of patients, and sustained remissions are uncommon. Immunotherapy with high-dose interleukin-2 yields objective tumor responses in a minority of patients; however, some of these responses may be durable. Identification of activating mutations of BRAF, NRAS, c-KIT, and GNAQ in distinct clinical subtypes of melanoma suggest that these are molecularly distinct. Emerging data from clinical trials suggest that substantial improvements in the standard of care for melanoma may be possible.

Systemic therapy of disseminated myeloma in passively immunized mice using measles virus-infected cell carriers

Multiple myeloma (MM) is bone marrow plasma cell malignancy. A clinical trial utilizing intravenous administration of oncolytic measles virus (MV) encoding the human sodium-iodide symporter (MV-NIS) is ongoing in myeloma patients. However, intravenously administered MV-NIS is rapidly neutralized by antiviral antibodies. Because myeloma cell lines retain bone marrow tropism, they may be ideal as carriers for delivery of MV-NIS to myeloma deposits. A disseminated human myeloma (KAS 6/1) model was established. Biodistribution of MM1, a myeloma cell line, was determined after intravenous infusion. MM1 cells were found in the spine, femurs, and mandibles of tumor-bearing mice. Lethally irradiated MM1 cells remained susceptible to measles infection and transferred MV to KAS 6/1 cells in the presence of measles immune sera. Mice-bearing disseminated myeloma and passively immunized with measles immune serum were given MV-NIS or lethally irradiated MV-NIS-infected MM1 carriers. The antitumor activity of MV-NIS was evident only in measles naive mice and not in passively immunized mice. In contrast, survivals of both measles naive and immune mice were extended using MV-NIS-infected MM1 cell carriers. Hence, we demonstrate for the first time that systemically administered cells can serve as MV carriers and prolonged survival of mice with pre-existing antimeasles antibodies.