A Phase 2, Multicenter Open-Label Extension (OLE) Study With ABT-122 in Active Psoriatic Arthritis Subjects Who Have Completed a Preceding Study M14-197

Inclusion Criteria: 1. Subjects who have completed preceding Study M14-197 (ABT-122) RCT study and have not developed any discontinuation criteria of Study M14-197. 2. If female, subject must meet one of the following criteria: * Postmenopausal (defined as no menses for at least 1 year). * Surgically sterile (bilateral oophorectomy or hysterectomy) If subject does not meet one of the above two categories, subject must use one of the following methods of birth control, from the time of the first dose of study drug until 150 days after the last dose of study drug: * Combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation started at least 2 months prior to the first dose of study drug: oral, intravaginal or transdermal * Progestogen-only hormonal contraception associated with inhibition of ovulation started at least two months prior to randomization: oral, injectable, or implantable * Intrauterine device (IUD) * Intrauterine hormone-releasing system (IUS) * Bilateral tubal occlusion/ligation * Be with a vasectomized partner (procedure at least 6 months earlier, the vasectomized male partner should be your sole partner) * Sexual abstinence (refraining from heterosexual intercourse during the entire study period) 3. If male, subject must be surgically sterile (have had a vasectomy more than 6 months prior to Screening) or must be practicing at least 1 of the following methods of birth control from the time of the first dose of study drug until 150 days post last dose of study drug: * Subject using condom and female partner(s) using an intrauterine device (IUD); * Subject using condom and female partner(s) using hormonal contraceptives (oral, vaginal, parenteral or transdermal); * Subject using condom and female partner(s) using double-barrier method (contraceptive sponge; diaphragm or vaginal ring with spermicidal jellies, creams, or spermicide); * Total abstinence from sexual intercourse as the preferred lifestyle of the subject; periodic abstinence is not acceptable. * Subject must also agree to not donate sperm starting on the first day of study drug administration until 150 days after the last dose of study drug. 4. Subjects must voluntarily sign and date an informed consent, approved by an Independent Ethics Committee (IEC)/Institutional Review Board (IRB), prior to the initiation of any study-specific procedures. 5. Subject is judged to be in good health as determined by the Investigator. Exclusion Criteria: 1. Pregnant or breastfeeding or plans to become pregnant during study participation. 2. Ongoing infections at Day 1 (Week 0) that have NOT been successfully treated within 14 days. 3. Anticipated requirement or receipt of any live vaccine during study participation including up to 120 days after the last dose of study drug. 4. Current enrollment in another investigational study; with the exception of Study M14-197, which is required. 5. Consideration by the Investigator, for any reason, that the subject is an unsuitable candidate to continue to receive ABT-122.