A Two-Part 26-Week Study of Etoricoxib as Treatment for Ankylosing Spondylitis (AS) (MK-0663-108)

Inclusion Criteria:

- Has a definite diagnosis of Ankylosing Spondylitis (AS) per Modified New York
Criteria made at least 6 months prior to screening

- Has a history of positive therapeutic benefit with non-steroidal anti-inflammatory
drugs (NSAIDs) and regular use of NSAIDS for past 30 days

- Has a score on Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) Question 2
at screening visit that is <77 mm

- Must demonstrate sufficient "flare" or worsening of AS pain

- Is in general good health (other than AS)

- Has had approved non-study antirheumatic therapy that has been at stable dosing AND
is not anticipated to undergo a change within the first 6 weeks of the protocol

Exclusion Criteria:

- Has inflammatory arthritis (eg, rheumatoid arthritis, psoriatic arthritis,
crystal-induced arthritis, spondyloarthropathy, diffuse idiopathic skeletal
hyperostosis [DISH]), polymyalgia rheumatica, a history of septic arthritis or
intra-articular fracture of the study joint, Wilson's disease, hemachromatosis,
ochronosis, or primary osteochondromatosis

- Has acute peripheral articular disease (onset within 4 weeks prior to screening) of
an active (painful or swollen) peripheral arthritis

- Has a history of gastric or biliary surgery, or small intestine surgery that causes
clinical malabsorption

- Has has an active peptic (gastric or duodenal) ulcer or history of inflammatory bowel
disease

- Has undergone coronary artery bypass graft surgery (CABG), angioplasty, or has a
cerebrovascular accident or transient ischemic attack within the past 6 months or has
active ischemic heart disease, cerebrovascular disease, or peripheral vascular
disease

- Has Class II-IV congestive heart failure

- Has uncontrolled hypertension

- Has a history of neoplastic disease (cancer or benign tumor), except adequately
treated basal cell carcinoma or carcinoma in situ of the cervix, or malignancies that
have been successfully treated ≥ 5 years prior to screening

- Has history of leukemia, lymphoma, malignant melanoma, and myeloproliferative disease

- Allergy to etoricoxib or naproxen, or history of a significant clinical or laboratory
adverse experience associated with etoricoxib or naproxen

- Has a history or family history of an inherited or acquired bleeding disorder

- Is considered morbidly obese and demonstrates significant health problems stemming
from obesity, which would confound study participation or interpretation of study
results

- Is pregnant, breast-feeding, or expecting to conceive during the study

- Has a clinical diagnosis of hepatic insufficiency defined as Child-Pugh score ≥ 5