Evaluation of the Efficacy and Safety of Bimekizumab (BZK) or Adalimumab (ADA) in the Treatment of Anterior Chest Wall Pain Associated With Active Axial Spondyloarthritis Refractory to NSAIDs With Hypothesis of Superiority of Bimekizumab

Inclusion Criteria: * Female or male adult-patients aged between 18 and ≤ 60 years * Patient having an established diagnosis by a rheumatologist of axial or predominantly axial SpA with or without psoriasis fulfilling the 2009 ASAS classification criteria * SpA evolving \> 3 months * bDMARD and JAKi naïve * History of inadequate response to at least 2 NSAIDs at a therapeutic dose range for \>= 2 weeks each or intolerance to \>= 2 NSAIDs for at least 3 months * Patient with active disease defined by ASDAS-CRP ≥ 2,1 * Patient with spontaneous pain of the ACW ≥ 4 /10 on NS * Patient with tenderness at the pressure of at least one of the four chondro-sternal joints of enthesitis MASES score * Stable dose of ongoing drug prescriptions (analgesics, NSAIDs) during the last month * Patient having read and understood the information letter and signed the consent form * Patient affiliated with, or beneficiary of a social security (health insurance) category * Women of childbearing potential (in accordance with CTCG recommendations, a woman is considered of childbearing potential (WOCBP), i.e. fertile, following menarche and until becoming post-menopausal unless permanently sterile): * with effective contraception (Cf. CTCG recommendations) (progestogen-only oral hormonal contraception, where inhibition of ovulation is not the primary mode of action, male or female condom with or without spermicide, cap, diaphragm or sponge with spermicide) since 1 month, during treatment and for 5 months after cessation of ADA and BKZ treatments and, * a negative blood pregnancy test by b-HCG at inclusion * Women permanently sterile (hysterectomy, bilateral salpingectomy and bilateral oophorectomy) * Postmenopausal women: In accordance with CTCG recommendations, a postmenopausal state is defined as no menses for 12 months without an alternative medical cause. A high follicle stimulating hormone (FSH) level in the postmenopausal range may be used to confirm a post-menopausal state in women not using hormonal contraception or hormonal replacement therapy. However in the absence of 12 months of amenorrhea, a single FSH measurement is insufficient Exclusion Criteria: * Pregnant woman; * Woman of childbearing potential not using effective contraception; * Patient with an history of chest trauma and/or chest surgery; * Patient with an history of radiotherapy in the anterior thoracic region; * Infiltration of a cortisone derivative performed in one or more joints of the ACW during the last 3 months; * Satisfaction of the 2016 ACR diagnostic criteria of fibromyalgia (Appendix 9); * Concomitant inflammatory bowel disease (IBD) (contraindication for IL-17i use); * Moderate or severe plaque psoriasis requiring higher doses of ADA or BKZ; * Analgesic treatment with strong opioids (WHO level III) with an average daily dose \> 30 mg/day of morphine (or equivalent) * One of the pre-biotherapy assessment not respected (viral serology, oral health consultation, evaluation of active or inactive ("latent") tuberculosis infection, …). * Patient with contraindication to BIMZELX® 160 mg, solution for injection in pre-filled syringe or pre-filled pen: * Hypersensitivity to the active substance or to any of the excipients, * Clinically important active infections (e.g. active tuberculosis) * Patient with contraindication to adalimumab (HUMIRA or one of its biosimilars (AMGEVITA, IMRALDI, HULIO, IDACIO, YUFLYMA, AMSPARITY, HYRIMOZ, HUKYNDRA)) : * Hypersensitivity to the active substance or to any of the excipients, * Active tuberculosis or other severe infections such as sepsis and opportunistic infections, * Moderate to severe heart failure (NYHA classes III/IV). * Patient with a contraindication to performing MRI in centers performing MRI for the study * Person deprived of liberty by an administrative or judiciary decision or person placed under judicial protection, under guardianship or supervision * Patient participating or having participated in a therapeutic drug trial in the 3 months prior to inclusion Randomization criteria : * Patient with at least one unequivocal inflammatory lesion of the ACW highlighted by MRI and/or ultrasonography and/or scintigraphy and/or CT scan \< 6 months at the time of randomization, validated by the investigator of each center (no central reading for inclusion procedure) * Woman of childbearing potential with negative urinary pregnancy test