By Randy Dotinga
THURSDAY, July 2, 2015 (HealthDay News) -- Just a few minutes of sun exposure can cause debilitating pain for people like Savannah Fulkerson, an 11-year-old with a rare genetic disorder.
Scientists say a new medication may allow Savannah and others like her to encounter daylight without such severe consequences.
Savannah has erythropoietic protoporphyria. "It's like she's allergic to the sun," her mother, Andrea Fulkerson, told multiple doctors as the family sought an explanation for the agony the child experienced when she encountered sunlight as a preschooler.
"We'd be outside about 20 minutes or so . . . she'd say, 'I burn!'" recalled Fulkerson. The pain was so intense that she'd scream "like she got hit by a car," her mother told ABC affiliate KABC-TV.
There's no cure for erythropoietic protoporphyria, but the new drug -- a tiny pellet inserted under the skin above the hip -- shows promise for helping people like Savannah.
"This is a life-changing treatment that will allow them to be exposed to sunlight longer without the fear of painful attacks," said study co-author Dr. Robert Desnick, dean of genetic and genomic medicine at Mount Sinai's Icahn School of Medicine in New York City. About 500 to 600 people in the United States suffer from erythropoietic protoporphyria, he said.
In the worst cases, patients can't tolerate more than a few minutes in daylight before suffering "a tingling, itching, burning feeling that's the warning signal to get out of the sun," he said. Too much sun exposure can lead to several days of excruciating pain.
"The sun does damage to you and me," he said, "and we react over the next couple days by tanning. They can't do that."
The condition often develops in childhood, prompting an "ingrained fear" of sunlight for life, he said.
For the new study, published July 2 in the New England Journal of Medicine, researchers randomly gave the drug, called afamelanotide, or an inactive placebo to 74 patients in Europe and 94 patients in the United States. They received an implant every 60 days for either 9 months or 6 months.
Participants calculated how much time they spent in the sun without pain. Over six months, U.S. participants who got the drug reported a median (half reported more, half reported less) of 69 hours of pain-free sun exposure compared to about 41 hours among those who got the placebo. In Europe, over nine months, those who used the drug reported a median of 6 hours of pain-free sun exposure compared to less than an hour among the others. The patients who took the drug also reported higher quality of life.
The researchers, whose work was partly funded by drug maker Clinuvel Pharmaceuticals of Australia, reported no serious side effects related to the medication. Gastrointestinal problems and fatigue were about as common in those who took the drug as in those who didn't, they said.
The drug works by stimulating melanin production -- the sunlight protection in normal skin, Desnick said.
One expert hailed the drug's development.
"This treatment is the first to work. So it is a fairly big deal," said Dr. Sylvia Bottomley, a professor of medicine at the University of Oklahoma Health Sciences Center who specializes in the disorder.
"Though not a cure, the beneficial effect of the medication is quite significant," said Bottomley, who wasn't involved in the study. "It uniformly allows the patients to tolerate considerably more exposure to the sun and visible light, without real side effects, and should be welcomed by all."
It's not clear when the drug will be available to U.S. patients. However, the study represents the last in three stages of research required for drug approval in the United States.
"The number of potential patients to undergo this treatment is relatively small, and one can predict that there likely will be no rush by other pharmaceutical companies to get a share of this market," said Dr. Claus Pierach, an erythropoietic protoporphyria specialist and professor at the University of Minnesota Medical School, who wasn't involved in the study.
The drug will probably be expensive, given the cost of developing it, Pierach said. "Once commercially available, it will likely be covered by insurance companies," he added.
For more about erythropoietic protoporphyria, see the American Porphyria Foundation.