Inclusion Criteria:

- Patients (18 years and ≤45 years) with axial SpA according to the ASAS criteria

- Active SpA assessed by physician.

- Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ≥ 4.

- Faecal calprotectin ≥ 100mg/kg.

- Negative pregnancy test (serum-HCG) for women of childbearing age before the start of
the study. (Women not of childbearing age are defined as postmenopausal for at least
1 year or surgically sterilised (bilateral tubal ligation, bilateral oophorectomy or
hysterectomy)). Women of childbearing age included in the study will be required to
use contraception during the entire study period (i.e. one of the following:
contraceptive pills, intrauterine device, depot injection of gestagen, subdermal
implant, hormonal vaginal ring or transdermal patch). In addition, contraception must
be used following any discontinuation of the study drug for a period of 150 days.

- Ability and willingness to self-administer the subcutaneous injections or have a
person available to administer the injections.

- Ability and willingness to give written informed consent and meet the requirements of
the study protocol.

Exclusion Criteria:

- Diagnosed inflammatory bowel disease or high risk of intestinal stricture (previous
abdominal stricture, radiation of abdomen, major abdominal surgery).

- Non steroid anti inflammatory Drugs (NSAID) ingestion less than 4 weeks before
inclusion.

- Psoriasis

- Persons with latent Tuberculosis (TB)(positive Mantoux skin test (>10 mm), positive
cultivation for mycobacteria in tissue samples and/or chest X-ray indicating TB) or
other risk factors for activation of untreated latent TB.

- Current or recurrent infections or serious infections requiring hospitalisation or
treatment with intravenous antibiotics within the last 30 days or oral antibiotics
within the last 14 days before inclusion.

- Positive serology for Hepatitis B or C indicating active infection.

- Medical history of positive HIV status (in case of suspicion control of HIV test).

- Medical history of histoplasmosis or listeriosis.

- Previous cancer or lymphoid proliferative disease except completely well-treated
cutaneous squamous cell carcinoma, basal cell carcinoma or cervical dysplasia.

- Previous diagnosis or signs of demyelinising diseases of the central nervous system
(e.g. opticus neuritis, disturbance of vision, disturbed gait/ataxia, facial paresis,
apraxia).

- Severe renal insufficiency (creatinine clearance < 35 ml/min - normogram).Affected
hepatic function: Liver enzymes > 3 x above the normal limit.

- Clinically significant drug or alcohol abuse in the last year or daily current
alcohol consumption.

- Diabetes, unstable ischemic heart disease, heart failure (NYHA III-IV), recent
apoplexia cerebri (within 3 months), chronic leg ulcer and any other condition (e.g.
indwelling catheter) which at the discretion of the investigator means that
participation in the protocol would entail a risk for the person in question.

- Anticoagulant treatment.

- Pregnancy or breast-feeding.

- Other clinically significant inflammatory rheumatologic diseases that cannot be
related to spondyloarthritis

- Current parvovirus B 19 infection.

- Glucocorticosteroid treatment within the last 4 weeks (except nasal and inhalation
steroids).

- Contraindication to study drug.