A once-daily pill has helped restore skin color in some people with vitiligo, a condition that causes white patches to appear on the skin.
The development could offer an easier treatment option, particularly for people whose vitiligo affects large or hard-to-reach areas of their body.
Unlike creams applied to individual patches, the tablet works throughout the body.
Vitiligo develops when the immune system mistakenly attacks the cells that give skin its color. The condition is not contagious, but its visible patches can affect people's daily lives and mental health.
People with vitiligo can experience stigma, anxiety, and social exclusion. Restoring skin color is therefore about more than appearance.
Current treatments include creams and light therapy. These can help return color to the skin, but often require repeated treatment over many months. Applying creams can also be difficult when vitiligo covers large areas.
The new study, published in The Lancet, tested a drug called upadacitinib in 614 adults and teenagers aged 12 or older.
The two trials were conducted at 138 institutions in 18 countries. All participants had the most common form of vitiligo, with patches affecting both their face and body.
Participants were randomly assigned to take either 15 milligrams of upadacitinib or a placebo once a day for 48 weeks. Neither the participants nor the researchers assessing their skin knew who was receiving the real drug.
In the first trial, 25 percent of patients taking upadacitinib regained at least 75 percent of the color lost from their face. Only 6 percent of those taking a placebo reached the same target.
The second trial produced almost identical results. The target was reached by 23 percent of patients taking the drug, compared with 7 percent of the placebo group.
Color also returned to other parts of the body. In the two trials, 19 percent and 21 percent of patients taking upadacitinib regained at least half of the color lost from affected areas. Only 6 percent of each placebo group experienced the same improvement.
Some patients saw even stronger results. Across both trials, 14 percent of treated patients regained at least 90 percent of the color lost from their face, compared with 2 to 3 percent of those taking a placebo.
Skin color was still returning when the 48-week trials ended, suggesting that longer treatment could bring further benefits.
Upadacitinib works by calming part of the immune response that drives vitiligo. This may reduce the attack on healthy skin cells and give affected areas an opportunity to regain color.
The drug belongs to a family of medicines called JAK inhibitors. Other drugs in this group have also been studied for conditions in which an overactive immune response damages the skin.
Because the pill works throughout the body, it may be particularly useful for people with widespread vitiligo or patches in places where creams are difficult to apply. It could also be more convenient than traveling to a clinic repeatedly for light therapy.
Upadacitinib has now been approved in the European Union for eligible adults and teenagers aged 12 or older with this common form of vitiligo. Its approval status varies elsewhere.
There are still important uncertainties. About three-quarters of patients taking the pill did not reach the main target for facial improvement. Roughly four in five did not regain at least half of the color lost across their body.
The most commonly reported problems included upper respiratory infections, acne, headaches, and inflammation of the nose and throat. Seven patients taking the drug developed shingles. Serious health problems were reported in 4 percent of treated patients in the first trial and 2 percent in the second.
The 48-week comparison was not long enough to rule out rare or long-term risks. Upadacitinib already carries warnings about serious infections, cancer, heart problems, and blood clots when used for other conditions.
Participants are being followed for another 112 weeks, which may reveal how much further improvement is possible.
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It is also unclear whether the restored color will remain after treatment stops.
The trials compared the pill with a placebo, not with existing creams or light therapy. Most participants were White, while people with darker skin were underrepresented.
The study was funded by AbbVie, the company that makes upadacitinib. AbbVie helped design the trials, analyzed the data, and participated in preparing the paper.
The findings provide some early evidence that a daily pill can restore a meaningful amount of lost skin color in some people. Longer studies will reveal how lasting those improvements are and help doctors decide who is most likely to benefit safely.
The study was published in The Lancet.
This article was fact-checked by Fiona MacDonald and edited by Peter Dockrill. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.