A pill that appears to cure alopecia baldness has fully restored the hair of three patients.
Doctors conducted the pilot trial after identifying the immune cells responsible for destroying hair follicles in people with the condition.
Within four or five months of being put on the drug, ruxolitinib, all three patients experienced complete hair growth.
US lead researcher Dr Raphael Clynes, from Columbia University Medical Centre in New York, said: “We’ve only begun testing the drug in patients, but if the drug continues to be successful and safe, it will have a dramatic positive impact on the lives of people with this disease.”
However, more research is needed before the drug can safely be used as a baldness treatment.
Alopecia is a common autoimmune disease that leads to partial or total hair loss. One of its best- known sufferers is former model and TV presenter Gail Porter, who refused to wear a hat or wig to hide her baldness.
There is no connection between alopecia and male pattern baldness that affects 6.5 million men in the UK and is hormone-driven.
The trial followed tests on mice using two new drugs known as JAK inhibitors that can be taken in pill form and block immune pathways.
Ruxolitinib is approved for the treatment of a form of bone marrow cancer in both the US and EU. The other drug, tofacitinib, is licensed for the treatment of rheumatoid arthritis in the US but not Europe.
In mouse experiments, both drugs completely restored the hair of animals with alopecia within 12 weeks. The trial patients all had moderate-to-severe alopecia areata, which causes patchy loss of head hair.