New biotherapies and anti-jak in pediatrics: between promises and prudence

Lyon-During the Congress of the French Pediatric Society. Similarly, a conference made it possible to detail the uses of anti-jak in pediatrics, in the field of gastroenterology, dermatology and rheumatology. Furthermore, These molecules are promising in the treatment of several pathologies refractory to other treatments. However, pediatric data is still incomplete and the side effects of these treatments should not be overlooked.

Anti-jak are inhibitors of Janus Kinase (Jaki), involved in a path of immunity and inflammation called Jak-Stat. Therefore, “Unlike biotherapies, these are small molecules, which are non -immunogenic”, explains the Dr. For example, Rémi Ducklaux-LorasPediatric gastroenterologist at the Women-Mère-Enfant Hospital in Lyon. Consequently, They have a short half-life and require a daily grip, or even twice a day.

“The Jak-Stat route is involved in many autoimmune. For example, inflammatory diseases, such as rheumatoid arthritis, Crohn’s disease, hemorrhagic rectocolitis or psoriasis,” new biotherapies anti-jak pediatrics: between he said.

In gastroenterology. Nevertheless, JAK inhibitors do not have a marketing authorization (AMM) in chronic inflammatory diseases of the intestine (IBD), increasing in children. Similarly, “The only AMM Available are those of Anti-TNFA which include infliximab and adalimumab,” says the specialist.

Interest in IBDs in adults

Clinical studies in rectocolitis hemorrhagic (HR) of adults have nevertheless shown significant remission thanks to anti-jak. Moreover, in comparison with a placebo. Furthermore, Tofacitinib, Filgotinib and Upadacitinib have notably shown their interest.

In children, there are currently only retrospective studies and no prospective data in HR.

“With Tofacitinib, a study on 101 children showed 23 % remission of patients without corticosteroids at weekly 24. Consequently, For Filgotinib, there are no data to my knowledge. Similarly, A phase III study is underway. For example, And for the Upadacitinib. Similarly, a multicenter retrospective test on 99 patients who experienced a failure of at new biotherapies anti-jak pediatrics: between least a biotherapy, highlighted a remission for 56 % of patients in week 8, without corticosteroids, “he develops. Nevertheless, The most frequently observed side effect was hyperlipidemia (13 patients).

In adult Crohn’s disease. “Filgotinib seems to be effective, with a significant improvement in clinical and endoscopic scores at week 10 in 665 patients. And the upadacitinib is the processing of which we have the most advanced data in this disease. with a significant improvement in scores in 49.5 % of patients against 29.1 % in week 12 and a healing of mucous membranes which reduces the risks of relapse in the year, “he adds.

Data does not exist in children for tofacitinib and fivility. “A monocentric study conducted on 20 patients with the Upadacitinib shows an improvement in clinical scores under treatment. but this requires confirmation with multicenter prospective studies,” he said.

For him. the advantage of these molecules is new biotherapies anti-jak pediatrics: between that they do not cause the patient’s immunization, are effective on extra-digestive symptoms and have a faster action than certain biotherapies, in a few days a few weeks.

“Anti-Jak have a demonstrated role in adults in the management of hemorrhagic rectocolitis. However, in children, there are not many studies, even if the upadacitinib seems to be interesting after failure of biotherapy. This type of treatment should therefore be used only in the third line. after discussion and validation in a multidisciplinary consultation meeting, ”he recommends.

New biotherapies anti-jak pediatrics: between

In pediatric dermatology. AMM in three indications

In pediatric dermatology, anti-jak have AMM in three indications: alopecia, vitiligo and atopic dermatitis. Helping is a non -serious disease, but whose psychological impact can be very important.

“Since 2024, the rilecitinib has had an AMM for severe excision, from 12 years old. However. it is necessary to think of carrying out new biotherapies anti-jak pediatrics: between a pre-therapeutic assessment, to verify in particular the absence of serious infection or tuberculosis, active or latent, ”warns the Dre Anne-Claire Bing-Lecointedermatologist at the Annecy hospital center (74).

In vitiligo. the cream ruxolitinib obtained an AMM in 2024, in non -segmental vitiligo with facial damage affecting less than 10 % of the total body surface. Its prescription is reserved for dermatology, hospital or city specialists.

“What has changed since 2024 is that it can be prescribed for adolescents over 12 years of age. adults, with active disease,” she notes. For children under the age of 12, the 0.1 % tacrolimus can be offered in compassionate prescription, from 2 years.

In atopic dermatitis. she emphasizes that “the application of dermocorticoids on the face of a child is still a problem for many doctors, wrongly”.

For her, “if you do not feel comfortable in this prescription, do not hesitate to hand over new biotherapies anti-jak pediatrics: between to a colleague”. A questionnaire “eczema and corticosteroid creams” makes it possible to measure the level of “corticophobia”.

The quantity of product used must also be well suited to each case. the duration of treatment should not be underestimated.

“You have to treat until complete healing and resume from the slightest recurrence,” she insists. In adolescents aged 12 to 17. she indicates that it is possible to go to Jaki if he suffers from a phobia of injections, if there is a quick action, in the event of predominant head and neck attack and if there is an associated pathology (vitiligo, excavation, MICI).

Upadacitinib and Abrocitinib benefit from AMM in adolescents. Again, their prescription can be done after a pre-therapeutic assessment and with biological follow-up. “However, you have to ask the question of side effects, as well as long -term effects,” recalls the dermatologist.

New biotherapies anti-jak pediatrics: between

Useful new biotherapies anti-jak pediatrics: between treatment in rheumatology

In rheumatology. “the advent of jaki was welcomed with great hope because they are oral drugs, unlike biotherapies that are injectable,” says the Dr. Isabelle Melkipediatrician at Armand Trousseau Hospital.

Tofacitinib. baricitinib have AMM in idiopathic juvenile arthritis in children over 2 years old, in the event of failure of first -line treatment. In Still’s disease. she believes that “this treatment may be useful, even if it does not have AMM in this indication”.

In juvenile dermatomyositis. an autoimmune disease that causes skin ulcers and muscle weakness, with possible very serious complications, metotrexate and corticosteroids are recommended in first intention in the current national and international recommendations.

“However, you should know that around 30 % of patients are resistant to first-line treatment,” she warns. In this context. a monocentric retrospective study has shown that the use of Jaki on 31 patients, including 24 refractories, allowed an new biotherapies anti-jak pediatrics: between inactivation of the disease at 6 months. Among the refractory patients, 54 % were in complete remission. For Dr. Melki “the use of Jak inhibitors can get us out of the rut but it is not magic”.

Side effects to monitor

In interferonopathy (pathology characterized by a constitutive activation of the interferon route. editor’s note), “the use of ruxolitinib is effective on certain cases, but it is necessary to take into account a certain number of criteria to prescribe it and pay attention to infectious risks”, she alerts. Thus. the risks of bacterial and fungal infection should not be overlooked, as are thromboembolic risks, even if they are extremely rare in children.

“Other complications may occur, for example metabolic (dyslipidemia, significant weight gain). Neoplastic risks exist especially in adults over 50. We must also be attentive to the possible drug interactions. as well as to withdrawal syndrome which new biotherapies anti-jak pediatrics: between can occur (cytokinic storm) ”, she lists.

For her, these risks justify the implementation of prospective surveillance registers. “We must also study the perspectives of combined therapies. in order to use lower doses and have less side effects,” she concludes.

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