Britain’s medicines regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), has approved deuruxolitinib, sold as Leqselvi, to treat adults with severe alopecia areata1. Alopecia areata is an autoimmune disease: the immune system mistakenly attacks hair follicles, causing inflammation and hair loss that can range from small bald patches to losing hair across the scalp and body1. The approval adds another treatment option for UK adults with the condition, which can affect the scalp, face and other parts of the body1.
Leqselvi is a tablet taken twice a day and is available on prescription only1. It is made by the Indian drugmaker Sun Pharma, which has sold it in the United States since the US Food and Drug Administration (FDA) approved it in July 202423.
What the pill does
Deuruxolitinib belongs to a group of drugs called JAK inhibitors. JAKs (Janus kinases) are enzymes that help pass along inflammation signals inside immune cells1. By turning down their activity, the medicine aims to calm the inflammation around hair follicles, which may allow hair to grow back1. Sun Pharma describes it as blocking two members of the family, JAK1 and JAK24.
Alopecia areata may affect up to 2.5% of people in the US and worldwide at some point in their lives, according to Sun Pharma, and it can come with anxiety and depression4. The company says approved treatment options remain limited4.
The evidence behind the approval
The MHRA based its decision on two large trials in adults with severe alopecia areata1. Everyone enrolled had lost at least half of their scalp hair for more than six months1. The trials compared deuruxolitinib at different doses with a placebo (a dummy pill) over 24 weeks1.
The sources give slightly different headcounts. The report on the MHRA approval says the trials involved 1,209 adults1, while Sun Pharma’s figures at the time of the US approval said the two trials, named THRIVE-AA1 and THRIVE-AA2, enrolled 1,220 patients3. Both trials were randomized and double-blind, meaning neither patients nor doctors knew who got the drug3. On average, patients started with only 13% of their scalp covered by hair3.
After 24 weeks, people on the approved dose regrew more scalp hair than those on the dummy pill1:
Put another way, most people in the trials did not reach the 80% mark within 24 weeks. The report on the approval notes that individual responses vary1.
Side effects and warnings
The most common side effects, each affecting more than 1 in 10 people, were headache and acne1. In the placebo-controlled trials, headache occurred in 12.4% of people on the drug versus 9.4% on the dummy pill, acne in 10% versus 4.3%, and cold-like nose and throat symptoms in 8.1% versus 6.7%4.
The US prescribing information carries a boxed warning, the FDA’s strongest type. Sun Pharma lists possible serious side effects including serious infections, cancers, blood clots, tears in the gut and certain abnormal lab results, and says there may be a higher risk of death and major heart events4. In the US the drug is not to be used in people whose bodies break down certain medicines poorly through a liver enzyme called CYP2C9, or in people taking drugs that block that enzyme4. The sources do not detail the wording of the UK label. The MHRA said it will keep monitoring the medicine’s safety and effectiveness after approval1.
What it does not show yet
The head-to-head comparison against a dummy pill lasted 24 weeks1. Evidence beyond that comes from follow-on studies, called open-label extensions, in which patients who finished the main trials could keep taking the drug and everyone knew they were on it3. Without a comparison group, these studies show whether people who stay on treatment keep their hair, but they cannot separate the drug’s effect as cleanly.
Sun Pharma has reported these longer results at medical meetings. In 2024 it said 32.6% of patients on the approved dose reached at least 80% scalp coverage at week 24, rising to 48.8% or 76.6% at week 68 depending on how the analysis handled people who left the study4. The higher figure counts only people still in the study, which tends to flatter results because people who drop out are often those doing worse.
In October 2026, at the European Academy of Dermatology and Venereology congress, Sun reported two-year data from a European extension study5. Among people who had already responded at the start of the extension, 93.9% kept their response through week 1085. Of those who had not responded at the start, 76.6% responded by week 52, and 96.8% of those kept it through week 1085. The company said most side effects were mild or moderate, and that no deaths, blood clots or major heart events were reported among people on the approved dose5. These results come from company presentations, not a full peer-reviewed paper among the sources here.
Other open questions the sources do not answer: how the drug compares directly with other JAK pills, and whether or when the NHS will pay for it in the UK.
Who is behind it
Sun Pharma gained the drug by paying $576 million in January 2023 to buy Concert Pharmaceuticals, the company that developed it3. The FDA accepted Sun’s application for review in late 20236, and the drug gained US approval in July 2024 with five years of US marketing exclusivity3. Analysts at Jefferies forecast it could reach $765 million in sales across the US and Europe by 20313.
Several doctors quoted in Sun’s announcements spoke favorably of the drug. Brett King, a dermatologist quoted in Sun’s 2024 release, said the data provided “insight into the durability of response”4. Arash Mostaghimi of Brigham and Women’s Hospital, quoted on the two-year data, said:
Collectively, these data show durable efficacy and maintenance of response for deuruxolitinib over time and reinforce the growing body of evidence supporting its use as a long-term treatment option for eligible adults.
That quote appeared in coverage of Sun’s own presentation5. The sources do not state whether these doctors have financial ties to the company. Sun also presented surveys in which patients and doctors, shown unlabeled profiles of Leqselvi and two other JAK pills, baricitinib and ritlecitinib, preferred Leqselvi’s profile4; those surveys were run and reported by the company.
How it fits the field
Leqselvi is one of several JAK inhibitor pills now used or tested for alopecia areata. Sun’s own comparison named baricitinib and ritlecitinib as other options4. Biohack has also covered the arthritis pill Rinvoq in this condition, including its trial results and its approval in Europe. Patient groups have long described the condition as more than a cosmetic issue. When the FDA began reviewing deuruxolitinib, Nicole Friedland of the National Alopecia Areata Foundation said people with the disease “are dealing with more than just hair loss”6.
What to watch next
- Whether the UK’s health system decides to fund Leqselvi, and for which patients.
- Full peer-reviewed publication of the two-year extension data Sun presented in October 20265.
- Safety reports after approval: the MHRA asks patients and health workers to report suspected side effects through its Yellow Card scheme1.
This article is news, not medical advice. Anyone with alopecia areata who is considering treatment should speak with a doctor.
