The drug is a combination of 5-fluorouracil, a common chemotherapy drug, and calcipotriol, a synthetic version of vitamin D. Both drugs are already approved for the treatment of skin-related conditions: 5-fluorouracil is prescribed for patients with actinic keratinosis, and calcipotriol treats psoriasis.
But together is better. In a trial, researchers found that the combination drug reduced the number of precancerous lesions on the face by 88 percent. By contrast, chemotherapy alone showed only a 26 percent reduction.
Of note, the drug is effective against early skin cancer known as actinic keratinosis. Untreated, this type of precancer evolves into squamous cell carcinoma, a fully dangerous skin cancer.
"We looked at precancerous lesions on patients with sun-damaged skin," said Washington University dermatologist and study co-author Lynn A. Cornelius, MD, director of the Division of Dermatology. "Most commonly found on the face, scalp and arms, these lesions appear abnormal by visual examination and under the microscope but are not full-blown skin cancers. But because these lesions have the potential to develop into a true skin cancer, they are commonly treated. Our study shows this combination therapy is more effective and better tolerated than current treatment practices."
The ease of application for this new chemo combo is unparalleled. The cream, applied topically on the skin, appears to boost the immune response. This sends more T cells to attack the abnormal cells at the precancerous lesions.
"The idea behind this study was to induce a heightened immune response in the skin using calcipotriol combined with the 5-fluorouracil that works to destroy the precancerous cells," Cornelius said. "In so doing, the destroyed precancerous cells release cell proteins, or antigens, and facilitate the heightened immune system to respond. We compared the two-drug formulation to 5-fluorouracil alone over a shorter application period -- four days as opposed to two to four weeks that is typical for the standard treatment of 5-fluorouracil alone."
"Because calcipotriol has been shown to induce an immune response, we are now interested in seeing if the anti-tumor immunity of the activated T cells can be recalled later to help prevent both precancerous and cancerous skin lesions," Cornelius said. "We are now planning to re-contact our patients to determine whether there are differences in precancerous and skin cancer rates between the two treatment groups."
Additional source: Washington University in St. Louis