interest of the dosage of adalimumab serum levels in crohn's disease patients for prevention of postoperative recurrence

Conditions: Crohn Disease

Summary: study comparing 2 modalities of crohn's disease patients postoperative follow-up treated with adalimumab (humira® or biosimilar) : immunomonitoring of adalimumab serum levels versus standard follow-up, which is based on the clinical and biological activity of the disease.

patients in the experimental arm will have a post-operative follow-up based on the immunomonitoring of serum levels of adalimumab. after ileocolic resection surgery, patients will have a therapeutic optimization of their adalimumab (humira® or biosimilar) treatment, based on their serum residual rate of adalimumab. patients in the control group will receive a standard post-operative follow-up, which is based on clinical and biological recurrence.

Eligibility criteria:
inclusion criteria: * patient between the ages of 18 and 75 * use of an effective method of contraception during treatment with adalimumab for women of childbearing age * crohn's disease diagnosed according to the criteria defined by the national and international recommendations for at least 3 months * iieocolic resection with ileocolic anastomosis and absence of residual macroscopic lesion, or ileocolic resection with transient ostomy and restoration of continuity * for anti-tnf-naive patients: negative pre-anti tnf balance * indication of postoperative treatment for the prevention of recurrence of crohn's disease (with at least 1 risk factor for recidivism): * active smoking (≥ 1 cigarette / day at the time of surgery) * hail resection\> 50 cm * second intestinal resection * presence of anoperineal lesions * penetrating impairment (b3 of the montreal classification) * biotherapy treatment for more than 6 months before the surgery * written and signed consent by the participant and the investigator * affiliated person or beneficiary of the social security system. exclusion criteria: * intolerance or allergy to adalimumab (humira® or biosimilar) * patients to whom adalimumab (humira® or biosimilar) is contraindicated * intestinal stoma without restoration of continuity * pregnant woman (dosage of positive βhcg) or breastfeeding according to article l1121-5 of the french public health law. * contraindication or refusal of ileocolonoscopy at 6 months * patient who could not be followed regularly for psychological, social or geographical reasons * vulnerable people according to article l1121-6 of the french public health law * persons subject to legal protection (guardianship, trusteeship) or unable to express their consent according to article l1121-8 of the french public health law or under the protection of justice according to article l1122.2 of the csp * concomitant participation of the patient in another research involving the human person. * patient not affiliated to the social security system (article l.1121-11). * patient unable to sign the consent form * immunized patients (with anti-adalimumab antibodies \> 10ng / ml and undetectable adalimumab levels, elisa drug sensitive technique used) for patients already treated with adalimumab (humira® or biosimilar) before surgery * patients in combination therapy with azathioprine, 6-mercaptopurine or methotrexate post-operative, or treated by another biotherapy (infliximab, vedolizumab, ustekinumab ...)