A new treatment for melanoma is currently being tested at Moffitt Cancer Center. The new treatment involves a single injection of Rose Bengal, or PV-10, a water-soluble dye used to stain damaged cells in the eye. When tested on mice, there was a reduction of melanoma lesions as well as a reduction of cancer that had spread to the lungs.
In the study, researchers injected PV-10 directly into the lesion as well as in the flank. They found that when the medication was injected directly into the lesion, there was a significant reduction in that lesion as well as lesions that had formed in other areas, such as the lungs. When the pV-10 was injected in the flank, the skin lesions were reduced but the secondary tumors and lesions were not. Scientists found that in addition to shrinking the tumors, the mice's anti-tumor immune response increased, leading to the reduction of tumors in the lungs.
Typical treatment for melanoma in Stage 4, where it has spread to other parts of the body, includes surgery of the initial lesion as well as surgery on the lymph nodes and other affected areas to remove all tumors. Immunotherapy drugs, such a ipilimumab or vermurafenib are used to boost the immune system to fight the cancer. These types of drugs have been found to be more effective than chemotherapy for melanoma, although chemotherapy is sometimes used. For some patients, a combination of chemotherapy and immunotherapy is used.
Once melanoma has reached Stage 4, it is difficult to treat and 10 year survival rates are about 10 to 15 percent. This number is based on the 2008 AJCC Melanoma Staging Database and may include "some people diagnosed with melanoma who may have later died from other causes, such as heart disease. Therefore, the percentage of people surviving the melanoma itself may be higher." 
This newest treatment offers hope to those with melanoma and may provide a safer alternative than other immunological agents currently being used. The study results were based on research on mice, however, the researchers are "currently in the middle of our first human clinical trial of PV-10 for advanced melanoma patients. In addition to monitoring the response of the injected melanoma tumors, we are also measuring the boost in anti-tumor immune cells of patients after injection,"  according to Amod A. Sarnaik, MD., a researcher at Moffitt's Cutaneous Oncology Program.
The study was supported by Provectus Pharmaceuticals, Inc. the company developing PV-10.
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"Intralesional Injection of Rose Bengal Induces a Systemic Tumor-Specific Immune Response in Murine Models of Melanoma and Breast Cancer," 2013, Paul Toomey et al, PLOS One
 "Single Injection May Revolutionize Melanoma Treatment," 2013, Aug. 26, Staff Writer, Medical News Today
"Treatment of Melanoma Skin Cancer by Stage," Revised 2013, May 30, Staff Writer, American Cancer Society
 "What Are the Survival Rates for Melanoma Skin Cancer by Stage?" Revised 2013, May 30, Staff Writer, American Cancer Society