Unexpected discovery has potential to effectively treat metastatic melanoma

New York-Researchers working under grants from the National Institute of Allergy and Infectious Diseases (NIAID) to investigate a fungus that causes infection in people with AIDS, have in the process discovered a potential strategy for treating metastatic melanoma.

The treatment involves combining an antibody with radiation. It has since been further developed and is expected to enter early-stage human clinical studies in the coming months.

Researchers from the Albert Einstein College of Medicine at Yeshiva University, here, began studying the biology of the skin pigment melanin to better understand why its synthesis plays a role in the process whereby the certain fungi cause cryptococcosis, an infection that can lead to death in people with AIDS.

The researchers created a monoclonal antibody that binds to melanin, based on scientific evidence suggesting that, when melanin is synthesized, it causes the immune system to react in a way that might create antibodies to combat the infection. Based on this finding, the researchers theorized that melanomas might contain melanin that would allow the monoclonal antibody to deliver radiation to tumor cells. Other researchers were brought in to investigate whether the melanin-binding antibody could be converted into an anti-tumor drug.

A subsequent 2004 study showed how the monoclonal antibodies were combined with radiation to create radiolabeled antibodies. These radiolabeled antibodies were tested in mice with melanoma tumors. After receiving a single dose of the radiolabeled antibodies, tumor growth in the mice was completely inhibited and near total tumor regression occurred in those animals with smaller tumors (0.6 to 0.7 cm in diameter). Further, the treated mice showed no signs of kidney or other organ damage and none died during the 30-day study. In the untreated control group, tumors continued to grow aggressively, and by the 20th day, all but one of the eight mice in this group had died.

In November 2006, Pain Therapeutics Inc., a San Francisco-based biopharmaceutical company, licensed the radiolabeled monoclonal antibody technology from the Albert Einstein College of Medicine. The company intends to begin testing it as a metastatic melanoma treatment in small human clinical trials in 2007.