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
