Dinitrophenyl hapten with laser immunotherapy for advanced malignant melanoma: A clinical study

The present study aimed to evaluate the efficacy and safety of in situ immunotherapy with dinitrophenyl (DNP) hapten in combination with laser therapy for patients with malignant melanoma (MM). Between February 2008 and March 2012, 72 patients with stage III or IV MM were enrolled. Patients received in situ DNP alone (n=32) or in combination with laser therapy (n=32), and each group received dacarbazine chemotherapy. The levels of peripheral cluster of differentiation (CD)4⁺CD25⁺ regulatory T cells (Tregs), interleukin (IL)-10 and tumor growth factor (TGF)-β were detected by ELISA. The association between delayed-type hypersensitivity (DTH) and survival time was evaluated. Although peripheral Treg levels significantly decreased over time in the two groups (P<0.001), there was no significant difference between the treatment groups (P=0.098). Patients receiving the combination treatment exhibited significantly higher interferon-γ production by CD8⁺ and CD4⁺ T cells (both P<0.001), as well as significantly reduced levels of IL-10, TGF-β1 and TGF-β2. In addition, patients in the combination treatment group experienced significantly longer overall survival (OS; P=0.024) and disease-free survival (DFS; P=0.007) times; a DTH response of ≥15 mm was also associated with increased OS time and DFS time (P≤0.001). Finally, no severe adverse events were observed in either treatment group. Overall, in situ immunization with DNP in combination with laser immunotherapy may activate focal T cells, producing a regional antitumor immune response that increases cell-mediated immunity and improves survival in MM patients. Thus, this may represent a novel therapeutic strategy for patients with unresectable, advanced MM.