When choosing the frst drug for genetically engineered biological therapy (GEBT), the following are taken into account: the psoriasis phenotype, diagnosed PsA or predictors of its development, the presence of comorbid pathology, contraindications, dosing regimen, the rate of onset of the effect, and the ‘survival rate’. With the advent of new classes of GEBT-drugs, the concept of ‘treat to target’ has been formed, in accordance with which the importance of achieving clear or almost clear skin as a goal of psoriasis therapy has been noted, since studies have shown that achieving clear or almost clear skin (PASI 90, 100) correlates with higher indicators of health-related quality of life. The concept is reduced to the long-term prescription of highly effective and safe therapies (methods) with a high level of evidence in medicine (A, B). The evolution of GIBT has led to the emergence of a new class of anti-IL-23 drugs. The article presents data from clinical studies on the effcacy and safety of the use of the interleukin-23 blocker guselcumab. Own clinical cases are presented with a discussion of the choice made in favor of guselcumab as the frst genetically engineered drug.Conclusions. Data from clinical trials on the high effcacy, ‘survival rate’ and safety of guselcumab in patients with psoriasis and psoriatic arthritis allows, including those with comorbid pathology, to consider it as a starting therapy using genetically engineered drugs. The data of our own results of observation allow us to conclude that guselkumab is highly effective in psoriasis of smooth skin, as well as in lesions of the scalp, anogenital area, with involvement of the nail plates in the process, which justifes its appointment as the frst GIBT drug.