A Study to Investigate the Safety, Tolerability, Pharmacokinetic, and Efficacy of ABY-035/AFO2

Inclusion Criteria: * Diagnosed with plaque psoriasis at least 6 months prior to Screening, if suitable for systemic treatment or phototherapy, and if have a stable active plaque-type psoriasis (stable is defined as without clinically significant flares during the 12 weeks before the first dose). Subjects with psoriatic arthritis may be included if they have not received systemic treatment within the last 12 months and their disease is stable * Subjects must use adequate contraceptive measures from the Screening Visit until 4 weeks after final administration of the investigational product * Subject that has a maximum body weight of 243 pounds (110 kg) Exclusion Criteria: * Subjects with psoriatic arthritis that have received systemic treatment within the last 12 months. * Subjects will not be eligible if they have current forms of psoriasis other than chronic plaque-type (e.g. erythrodermic, guttate, or pustular) * Subject that has a current drug-induced psoriasis form (e.g. a new onset of psoriasis or an exacerbation of psoriasis from beta blockers, calcium channel blockers, or lithium) * Subject that has a history of recurrent or medically important infections, a clinically significant candida infection or clinically significant skin infection with Staphylococcus aureus requiring systemic treatment in the last 12 months prior to the first administration of study drug * Subject that smokes more than 15 cigarettes, or equivalent in tobacco, per day Subject with a history of suicide attempt or suicidal behavior * Any live vaccination within 3 months prior to Screening * Subject that is pregnant, intends to become pregnant during the course of the study, or is lactating