New treatment for advanced melanoma lesions

This study examined PV-10, an injection of rose bengal disodium, as a treatment for melanoma.

Treatment for patients with metastatic melanoma (melanoma that has spread to distant sites) can be difficult. Even though average survival times can be long, new lesions and differences in the genetic makeup of the disease mean that the same treatments do not work for every patient. Therapies include surgical removal of the lesions, chemotherapies, and drugs targeted to the specific disease subtypes, but very few of these treatments offer long-term disease control with few side effects.

PV-10 is a new treatment composed of rose bengal disodium, a dye which has been shown to destroy cancer cells when injected directly into lesions. One study found that one dose of PV-10 led to an overall response rate (such as tumor shrinkage or disease that neither worsens nor gets better) in 55% of patients at 12 weeks following injection.

The current study examined the long-term effect of PV-10, including the effect of multiple doses, over a 52-week period.

80 patients with stage 3 (cancer has spread to nearby tissues and lymph nodes are involved) or stage 4 (spread to distant areas) melanoma received an injection of PV-10 directly to lesions at the start of the study. Second injections or first injections to further lesions were allowed at weeks 8, 12, and 16. Patients were evaluated as to number and size of lesions at the start of study, at days 1 and 7 after injection, then every 4 weeks through week 16 (the treatment period). Following week 16, patients were evaluated at weeks 24, 36, and 52 (the long-term follow-up period). Overall response rates (such as tumor shrinkage), progression free survival (time from treatment until disease progression), and overall survival (time from treatment until death from any cause) were measured.

51% of patients saw an overall response to treatment (26% had complete disappearance of signs and symptoms, 25% had partial disappearance of signs and symptoms). 8% had no evidence of disease after 52 weeks.

For patients with “bystander lesions”, or nearby lesions that did not receive their own injections, 26% had a complete disappearance of signs and symptoms of cancer in the uninjected lesions, 7% had a partial disappearance of signs and symptoms, and in 17% lesions did not improve but also did not get worse. The average overall survival for all patients was not met by the end of the study, though for patients with stage 3 disease the average overall survival was more than 12 months, and for those with stage 4 disease the average overall survival was 6.5 months.

All patients experienced at least one adverse (negative) side effect, though most were not serious. The most common included pain and swelling at the injection site.

This study concluded that PV-10 injected directly into melanoma lesions reduced the size and progression of both injected and bystander lesions.