The Medicines and Healthcare products Regulatory Agency has extended the UK marketing authorisation for leniolisib, sold as Joenja, to children aged 4 to 11 who weigh at least 27kg and have activated PI3K delta syndrome, a rare inherited immune disorder. The manufacturer, Pharming, announced the decision on 6 November.
Adults and adolescents aged 12 and over were already covered by the existing UK indication, which now widens to include younger children. Those who qualify are dosed at 40mg or 50mg twice daily, with the dose set by weight. The manufacturer describes the medicine as the first treatment approved in the UK specifically for children with the condition.
Who is now eligible
Eligibility is narrow by design. A child must be at least four years old, must weigh at least 27kg, and must have a diagnosis of the disorder. The weight threshold sits alongside the age range rather than inside it, so both tests have to be met, and a child at the younger end of the band qualifies only if they reach 27kg.
Supporting the decision was data from a paediatric investigation plan agreed with the regulator, together with pharmacology and safety assessments. A paediatric investigation plan is the agreed programme of studies a company must complete to show that a medicine behaves acceptably in children, whose dosing and metabolism differ from those of adults.
Extensions of this kind usually follow an adult licence rather than precede it. The medicine is first authorised for the population in which it has been studied, and the paediatric plan then sets out what further work is required, and by when, before younger patients can be included.
A diagnostic gap
The condition affects roughly 1 to 2 people per million. It is often misdiagnosed, and the reported median delay before a correct diagnosis is about seven years. For a child, that delay can span most of childhood, and a licence that stopped at 12 left little time to act on it.
Rarity shapes the evidence base as well as the patient experience. Small populations mean small studies, and licensing decisions in this field rest on data packages assembled from far fewer patients than would support a common disease.
Access from February
Availability for the expanded group is expected in February 2027, and the manufacturer said it will work with the NHS on access. Until then, the licence defines who may be prescribed the medicine without putting it in a pharmacy, and access will depend on health service decisions as well as on the authorisation itself.
A consultant paediatric immunologist at Great Ormond Street Hospital said the extension gives younger children a targeted option without waiting until they are older, a point that turns on timing rather than on any comparison with existing care.
The authorisation sets out who may be treated and on what evidence. It does not establish how children will fare over years of treatment, and the announcement did not present long-term outcome data. Families and clinicians will be working from the terms of the licence and from the specialist assessment that accompanies any prescription.
For a family already in the system, the difference is concrete. A child who meets the age and weight criteria becomes eligible for a medicine previously licensed only from the age of 12, which for a four-year-old is the gap between an option now and an option in eight years.
