Some people have one or two spots. Others have dozens across their chest and back. “The sheer number of lesions can be depressing,” said Victor Neel, the director of dermatologic surgery at Massachusetts General Hospital, adding that he has heard people say “they haven’t taken off their shirt at the beach in 25 years.”
Before Eskata, dermatologists could freeze lesions or use a laser or scalpel to remove them, but the procedures could be painful and patients didn’t necessarily want to risk potential scarring for a cosmetic annoyance.
Here’s how Eskata works: After a dermatologist has determined a spot is not cancer, a staff person (not necessarily a doctor) delicately applies the highly concentrated hydrogen peroxide liquid to each lesion four times, roughly a minute apart. The idea is to moisten the lesion to dissolve it, while avoiding damaging surrounding skin.
Noelle Galperin, a 49-year-old strategy consultant in Miami who participated in a clinical trial at Leslie Baumann’s office, said she felt a “tingling, almost burning, sensation.” Later, scabs formed on her lesions, and she wore an adhesive bandage for a few weeks to hide the spots from the sun.
Ms. Galperin used to be so self-conscious about the lesion on her forehead that she would Photoshop it out of pictures. “Who wants to be seen with brown age spots?” she said. After her Eskata treatments, the spot on her forehead is gone with no scar or sign she had it removed.
She also wanted two larger spots on her back treated so “there’s no chance of seeing them in my wedding dress,” said Ms. Galperin, who will marry soon in France in a gown with a V-shaped back in scalloped lace. One is gone, but the other, she said, will need another treatment to remove it completely.
“Patients need to know that there’s a chance after two treatments their lesion may be gone and they’ll be happy,” said Robert T. Brodell, the chairman of the department of dermatology at the University of Mississippi Medical Center in Jackson, Miss. “Or some may have a lesion that’s 90 percent better, or some might take a third touch-up treatment.”
Still, Dr. Brodell called Eskata “something that’s totally different that’s an advance.”
In one study, approximately 65 percent of the facial lesions on roughly 220 patients were completely or almost clear 106 days after the first treatment, compared with 15 percent of roughly 225 patients who got a placebo liquid.
In another study, about 50 percent of all SKs treated with Eskata in the trial were assessed as clear or near clear, according to Neal Walker, a dermatologist and the chief executive of Aclaris Therapeutics.
In an interview, Dr. Walker estimated that each Eskata applicator will cost the patient $200 to $250. One applicator, he estimated, will be able to treat seven large spots up to 1.5 centimeters wide, or 10 smaller ones.
Dr. Neel is starting a company to bring to market his own topical treatment for SKs, one that would theoretically work by inhibiting an enzyme that the lesions need for survival. The lesion would die, but the regular skin wouldn’t be damaged, so large areas of skin could be treated quickly. But that is years off.
Some research has found that Eskata has minimal side effects when carefully applied. More than 90 percent of the mostly white patients had no scarring or pigmentation issues. But darker skin tends to have more trouble with pigmentation and scarring after, say, cryotherapy. Ninety-eight percent of patients in the clinical trials were Caucasian.
“It’s a huge gap in the study design,” Dr. Marmur said.
The Fitzpatrick phototyping scale classifies complexions from Type 1 (ivory) to 6 (very dark). In one study to measure the effectiveness and safety of Eskata, no patients had the darkest skin tone, and only four of the 450 enrolled participants had Type 5, which resembles Beyoncé’s skin.
“Although the numbers were small, I think the safety profile showed very well,” Dr. Walker said when asked why Aclaris research didn’t enroll more patients with darker skin. The F.D.A. label for Eskata allows patients of any skin type to be treated.
The company is currently studying Eskata’s safety and effectiveness in a dozen or so patients with the darkest skin types who have the kind of SK lesions that look like tiny raised lentils. They’re called dermatosis papulosa nigra.
Dr. Marmur said that until that research is published, she would do a test spot before using Eskata on darker skin. “That patient might come back with a big keloid,” a scar bigger than the disliked spot, she said.
As for Ms. Galperin, she would love to get the stubborn brown spot on her back treated again before her February wedding, and tackle another raised spot on her back.
Alas, Eskata won’t be commercially available until April, too late for her big day.
Correction: January 23, 2018
An earlier version of this article misstated Robert T. Brodell’s title. He is the chairman of the department of dermatology at the University of Mississippi Medical Center, not a spokesman for the American Academy of Dermatology.