A phase 4, multicenter, randomized, double-blind, placebo-controlled, parallel-group study to evaluate the efficacy and safety of apremilast (CC-10004) in subjects with early, oligoarticular psoriatic arthritis despite initial stable treatment with either non-steroidal anti-inflammatory drugs (NSAIDs) and/or <=1 conventional synthetic disease-modifying antirheumatic drugs (DMARD).

1. 1. Subject is a male or female, >= 18 years at time of consent.
2. Subjects must understand and voluntarily sign an informed consent document
prior to any study related assessments/procedures being conducted.
3. Subject is willing and able to adhere to the study visit schedule and other
protocol requirements.
4. Subject must have a documented diagnosis of PsA (by any criteria) of >= 3
months but <= 24 months duration at the time of the Screening Visit.
5. Subject meets the CASPAR (Appendix B) criteria for PsA at the Screening
Visit.
6. Subject must have a total number of swollen joints greater than 1 and equal
or less than 4 (> 1 but < 4 swollen joints) at the Screening Visit and
confirmed prior to randomization at the Baseline Visit.
7. Subject must have a total number of tender joints greater than 1 and equal
or less than 4 (> 1 but < 4 tender joints) at Screening and confirmed prior to
randomization at the Baseline Visit.
8. Subjects taking oral glucocorticosteroids must be on a stable dose of
prednisone <= 10 mg/day or equivalent for at least 4 weeks prior to the Baseline
Visit (Section 8.1).
9. For all regions, the local Regulatory Label for treatment with apremilast
must be followed. For example, subjects in the EU must have had inadequate
response or intolerance to a prior csDMARD.
10. Subjects taking 1 protocol-allowed csDMARD (methotrexate [MTX] or
sulfasalazine [SSZ]) may enter the study provided that the duration of
treatment is <=6 months prior to the Baseline Visit and treatment is taken at a
stable dose for at least 3 months prior to the Baseline Visit. See Permitted
Medications (Section 8.1) for details describing dose criteria.
11. Subjects exposed to MTX or SSZ and stopped treatment due to intolerance or
due to safety reasons may enter the study provided that treatment was stopped
within at least 4 days of the Baseline Visit.
12. Subjects taking NSAIDs may enter the study provided that the dose is stable
for at least 2 weeks prior to the Baseline Visit. Subjects may discontinue
NSAIDs at any time up to and including the Baseline Visit, prior to study
randomization.
13. Females of childbearing potential (FCBP*) must have a negative pregnancy
test at Screening and the Baseline Visit. While on investigational product and
for at least 28 days after taking the last dose of investigational product,
FCBP who engage in activity in which conception is possible must use one of the
approved contraceptive** options described below:
Option 1: Any one of the following highly effective methods: hormonal
contraception (oral, injection, implant, transdermal patch, vaginal ring);
intrauterine device (IUD); tubal ligation; or partner*s vasectomy;
OR
Option 2: Male or female condom (latex condom or non-latex condom NOT made out
of natural [animal] membrane [for example, polyurethane]); PLUS one additional
barrier method: (a) diaphragm with spermicide; (b) cervical cap with
spermicide; or (c) contraceptive sponge with spermicide.
NOTE: Option 2 may not be acceptable as a highly effective contraception option
in all countries per local guidelines/regulations.
*A female of childbearing potential is defined as a sexually mature female who:
1) has not undergone a hysterectomy (the surgical removal of the uterus) or
bilateral oophorectomy (the surgical removal of both ovaries) or 2) has not
been postmenopausal for at least 24 consecutive months (that is, has had menses
at any time during the preceding 24 consecutive months).
**The female subject*s chosen form of contraception must be effective by the
time the female subject is screened into the study (for example, hormonal
contraception should be initiated at least 28 days before screening).
14. Must be in general good health (except for psoriatic arthritis) as judged
by the Investigator, based on medical history, physical examination, and
clinical laboratories. (Note: The definition of good health means a subject
does not have uncontrolled significant comorbid conditions).

1.1. Prior use of >1 cs DMARD.
2. Prior exposure to a JAK-inhibitor, including tyk2 inhibitors and/or a
biologic DMARD.
3. Use of intra-articular (IA) or intra muscular (IM) glucocorticoid injection
within 8 weeks before the Baseline Visit.
4. Use of leflunomide within 12 weeks of randomization. Subjects who stopped
leflunomide and completed 11 days of treatment with cholestyramine (8 g, 3 x
daily) prior to the Baseline Visit may enter the study.
5. Prior use of cyclosporine.
6. Prior treatment with apremilast, or participation in a clinical study,
involving apremilast.
7. Use of any investigational drug within 4 weeks of the Baseline Visit, or 5
pharmacokinetic/pharmacodynamic half-lives, if known (whichever is longer).
8. History of clinically significant or uncontrolled disease (as determined by
the Investigator), which places the subject at unacceptable risk if he/she were
to participate in the study.
9. Any condition, including the presence of laboratory abnormalities, which
places the subject at unacceptable risk if he/she were to participate in the
study. Subjects with a creatinine clearance level less than 30 mL/min
(estimated by the Cockcroft-Gault equation) will be considered to have severe
renal impairment and will be excluded from the study.
10. Prior history of suicide attempt at any time in the subject's lifetime
prior to signing the informed consent, or major psychiatric illness requiring
hospitalization within the last 3 years prior to signing the informed consent.
11. Pregnant or breast feeding.
12. Active substance abuse or a history of substance abuse within 6 months
prior to Screening.
13. History of allergy or hypersensitivity to any component of the
investigational product.
14. History of positive human immunodeficiency virus (HIV), or congenital or
acquired immunodeficiency (eg, Common Variable Immunodeficiency Disease).
15. Active tuberculosis or a history of incompletely treated tuberculosis.
16. Bacterial infections requiring treatment with oral or injectable
antibiotics, or significant viral or fungal infections, within 4 weeks of
Screening. Any treatment for such infections must have been completed and the
infection cured, at least 4 weeks prior to Screening and no new or recurrent
infections prior to the Baseline Visit.
17. Malignancy or history of malignancy or myeloproliferative or
lymphoproliferative disease within the past 3 years, except for treated (ie,
cured) basal cell or squamous cell in situ skin carcinomas.
18. Major surgery (including joint surgery) within 8 weeks prior to the
Screening Visit or planned major surgery within 6 months following the Baseline
Visit.
19. Rheumatic autoimmune disease other than PsA, including, but not limited to:
systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD),
scleroderma, polymyositis, or fibromyalgia.
20. Prior history of or current inflammatory joint disease other than PsA (eg,
gout, reactive arthritis, rheumatoid arthritis [RA], ankylosing spondylitis,
Lyme disease), which confounds the ability to interpret data from the study.
21. Erythrodermic, guttate, or generalized pustular psoriasis at randomization.