REduCed Dose of TNFi in Patients With Ankylosing SpondyliTis (RECAST)

Participants maintaining stable disease activity of Ankylosing Spondylitis (AS) with standard-dose tumor necrosis factor inhibitor (TNFi) treatment will randomly split into two groups: maintaining standard-dose TNFi, versus reduced-dose TNFi. The proportion of participants not underwent flare between the two groups will be analyzed.


Eligibility Criteria:
Inclusion Criteria:

* Documented diagnosis of Ankylosing spondylitis (AS) and meet the modified New York classification criteria for AS.
* Subjects maintaining stable disease (Bath Ankylosing Spondylitis Disease Activity Index \[BASDAI\] \< 4) with standard-dose subcutaneous tumor-necrosis factor inhibitor (TNFi) treatment during previous 6 months from screening.
* Ankylosing Spondylitis Disease Activity Score (ASDAS) \< 2.1 at screening and 12 weeks prior to screening
* In subjects treated with methotrexate or sulfasalazine, the dose should be maintained (methotrexate≤ 25mg/day, sulfasalazine ≤ 3 g/day) during previous 4 weeks before screening.
* In subjects treated with systemic glucocorticoids, the dose should be less than 10mg/day of predinisolone or equivalent during at least 2 weeks from the screening
* Subjects with stable dose of concomitant NSAID (including Cox2 inhibitors) during the 2 weeks from the randomization

Exclusion Criteria:

* Exposure to more than 1 TNFi
* History of hypersensitivity reaction to any TNFis
* Subjects with concomitant fibromyalgia, as determined by the investigator
* Subjects who have received any TNFis with reduced dosage
* Presence of total spinal ankylosis ('Bamboo spine')
* Female subjects who are breastfeeding, pregnant, or plan to become pregnant during the study
* Subjects with a history of malignancies and lymphoproliferative disorder including lymphoma within 5 years (Basal cell carcinoma treated within previous 3 months and showing no evidence of recurrence, actinic keratosis, and treated cervical/colon carcinoma in situ were allowed.)
* Subjects with current or history of severe, progressive, and/or uncontrolled renal, hepatic, hematological, endocrine, pulmonary, cardiac or neurological disease, as determined by the investigator
* Subjects with significant laboratory abnormalities included but not limited to:

  1. AST/ALT \> 3.0 X ULN
  2. White blood cell (WBC) \< 3000/μL and/or absolute neutrophil count (ANC) \< 1500/μL
  3. Platelet count \<100,000/μL and/or hemoglobin level \<8.5 g/dL
  4. Serum creatinine ≥ 1.5 X ULN
* Subjected with any high-potency opioids (ex. methadone, hydromorphone, morphine, oxycodone, oxymorphone, fentanyl, levorphanol, buprenorphine, meperidine)
* Subjects with current acute or chronic viral hepatitis B or C or with human immunodeficiency virus (HIV) infection
* Subjects planning to receive any live attenuated vaccinations after screening
* Subjects has history of chronic alcohol abuse or drug abuse within 6 months from screening
* Subjects concomitantly treated with systemic glucocorticoid (\>10mg/day of prednisolone or equivalent doses)
* Subjects with any other condition that, in the Investigator's judgment, would make the subject unsuitable for inclusion in the study