Melanoma immunotherapies must prove efficacy, physician says

Chicago - While immunotherapies for melanoma continue to seek scientific validation, a leading researcher says dermatologists must not lose sight of existing treatment options.

"Treating many melanomas requires some therapy other than simply resecting the tumor. Immunotherapy is one approach that may or may not work."

"There are two very simple ways of reducing mortality from the disease, and these are things that dermatologists are best suited to do," Dr. Bystryn adds.

Prevention

One is that reducing mortality from melanoma begins with prevention.

"In my view," he says, "part of treatment is to prevent the disease from happening" by minimizing sun exposure and taking other well-known precautions.

"If melanoma does appear," Dr. Bystryn adds, "one treatment that we know works very well is to remove the lesion surgically before it has a chance to spread. The key to that is early detection. If we do these two things, we can reduce mortality from melanoma significantly. That message needs to be re-emphasized every time people talk about melanoma.

"There is no current therapy that seems to work in terms of prolonging survival in melanoma above and beyond simply resecting the tumor early. There's an anxiety to find new ways that might work."

Immune response

Researchers' current interest in immunotherapy for melanoma stems partly from the fact that there's "intriguing evidence that immunological approaches can and do work," according to Dr. Bystryn.

"Maybe the clearest manifestation of that is simply what we can see clinically as dermatologists - if one looks at a primary melanoma lesion on the skin, in about 20 percent of cases, there will be areas of white within the melanoma. These are areas where the melanoma cells have been killed by a mechanism in the body that can differentiate between a malignant pigment cell and a normal one. The white is in the melanoma, not in the normal skin surrounding it. So whatever is causing the destruction has this exquisite ability to differentiate between these two types of cells. The only thing we know of that can do that is the immune system," though not as powerfully as one would like, he says.

Various approaches exist for augmenting the body's immune response to melanoma.

"But the bottom line is that most of these have not really proven to be effective in double-blinded, placebo-controlled trials," he says. "The typical data that leads people to be encouraged comes from studies in which relatively small groups of patients are treated, and where some of them have partial or complete regression. These improvements are usually ascribed by the investigator as being results of the treatment. However, the fact is that no matter what one does to melanoma in terms of treatment, the response rate appears to be about the same. It makes one wonder whether what we observe is really the effect of the treatment or simply the biology of the disease."

Immunological approaches

Currently, two immunological approaches have received Food and Drug Administration (FDA) approval.