ABSTRACT: Cytokines have been used in the treatment of patients with cutaneous melanoma. Granulocyte-macrophage colony-stimulating factor (GM-CSF, sargramostim(Drug information on sargramostim) [Leukine]) leads to dendritic cell/macrophage priming and activation, and also increases interleukin-2 (IL-2) receptor expression on T lymphocytes. IL-2 creates lymphokineactivated killer cells and tumor-infiltrating lymphocyte cells. In this open-label, single-arm study of 16 high-risk patients, we combined these two agents to take advantage of their different but complementary functions. All patients underwent potentially curative surgery. Postoperatively, each patient received GM-CSF at 125 μg/m2/d subcutaneously (SC) for 14 days; this was followed by IL-2 at 9 million IU/m2/d SC for 4 days, and then 10 to 12 days of no treatment. In addition, patients who had large tumors that could yield over 100 million live tumor cells received autologous melanoma vaccines. The duration of follow-up ranged from 21 to 42 months (median: 27 months). During follow-up, five patients developed metastases. This program was carried out on an outpatient basis, and no hospitalization was required. It was well tolerated with minimal side effects. The combination treatment regimen of GM-CSF and IL-2 with or without autologous vaccine used adjuvantly appears to benefit high-risk melanoma patients; further clinical testing of this regimen is warranted.
Several cytokines have been utilized in the management of patients with cutaneous melanoma. Interferon alfa-2b(Drug information on interferon alfa-2b) (IFN) is the only agent approved by the US Food and Drug Administration (FDA) as adjuvant therapy in melanoma. However, it has had borderline survival benefits that disappear during follow-up. Interferon alfa-2b has to be administered for 1 year at a high dose that is associated with a high toxicity level, and it cannot be administered to the elderly. In 2002, the Oncology Advisory Committee of the FDA recommended that physicians do not have to offer IFN to patients as it is no longer considered standard treatment.
On the other hand, interleukin-2 (IL-2) is approved by the FDA for the management of metastatic melanoma. The in vitro culturing of peripheral blood mononucleated cells with IL-2 results in lymphokine-activated killer (LAK) cells. In addition, culturing lymphocytes from metastatic melanoma, specifically from soft tissues, with IL-2 gives rise to tumor-infiltrating lymphocyte (TIL) cells, which are specific cytotoxic lymphocytes. These TIL cells are more potent than the LAK cells.
The newest cytokine to be used as adjuvant therapy in melanoma is granulocyte- macrophage colony-stimulating factor (GM-CSF, sargramostim [Leukine]). It is the least toxic cytokine, and early results from its use as adjuvant therapy in melanoma are very encouraging. GM-CSF serves as the principal mediator for the proliferation, maturation, and migration of dendritic cells, which are antigenpresenting cells (APCs) that play a major role in the induction of primary and secondary T-cell immune responses.[1,2]
Spitler and coworkers evaluated the safety and efficacy of adjuvant GMCSF in patients with stage III and resected stage IV melanoma who were at a very high risk of recurrence and metastases. Their results showed significant improvement in survival when compared to historical controls. While nearly all immune responses require T lymphocytes, appropriate presentation of tumor antigen with costimulatory molecules and cytokines is necessary for triggering an immune response. Antigen-presenting cells are crucial players in this process, as they are phagocytic cells that trap, process, and display antigens for T-cell recognition.
In this study we utilized two cytokines, GM-CSF and IL-2, each having a function different from but complementary to that of the other. In addition, when GM-CSF was injected directly at melanoma sites, it was noted that the absolute number of CD4+ T lymphocytes and the number of dendritic cells in the epidermis were increased. Furthermore, the IL-2 receptor expression on T lymphocytes, both around and within the tumor, was increased. Such findings correlated with the responses seen in a study by Si and associates. This further justifies the use of the combination of GM-CSF and IL-2.
Materials and Methods
This was an open-label, single-arm study, approved by the Institutional Review Board. The high-risk patients who participated in this study underwent potentially curative surgery, eliminating all gross tumor. The study was comprised of patients with primary tumors of 2 to 4 mm deeply invasive melanoma with ulceration, patients with > 4 mm deeply invasive melanoma with and without ulceration, those with metastases to their regional lymph nodes, and patients with resected distant metastases with no gross residual tumor.
Postoperatively, each patient received GM-CSF at 125 μg/m2/d subcutaneously (SC) for 14 days. This was followed by IL-2 at 9 million IU/m2/d SC for 4 days. The patient then received no treatment for the next 10 to 12 days (see Figure 1). Each of the first 16 patients received six cycles over a 6-month period. The protocol was then modified to a 2-year program; to date, 12 patients have been enrolled in the modified protocol.
In addition, patients who had large tumors that could yield over 100 million live tumor cells received autologous melanoma vaccines. All patients were observed closely without further therapy. In the event of recurrence or metastases, the patient was evaluated for resection; if surgery rendered the patient grossly disease-free, he or she was treated on the same program.
The first 16 patients enrolled in this study, who received only 6 months of adjuvant GM-CSF and IL-2, included 5 patients with 2 to 4 mm deeply invasive melanoma with ulceration, 3 patients with > 4 mm deeply invasive melanoma (2 of these patients had ulcerated lesions), 5 patients with regional lymph node metastases, and 3 patients with resected distant metastases.
There were eight men and eight women, ranging in age from 33 to 75 years (median: 50 years). The duration of follow-up ranged from 21 to 42 months (median: 27 months). During follow-up, five patients developed metastases. Two patients underwent resection of their metastases (one from lung and the other from soft tissue and adrenal gland) and are being treated on the 2-year program. These two patients are living free of disease at 1 and 2 years since the initiation of their 2-year treatment. The third patient died of metastases, and another patient is living with metastases. The fifth patient had brain metastasis that was resected, and received postoperative brain irradiation, and is alive with no evidence of disease for 12 months.