Netakimab (NTK) is an anti-interleukin-17A monoclonal antibody approved for psoriasis, ankylosing spondylitis, psoriatic arthritis (PsA) in Russia and Belarus. PATERA is an ongoing phase 3 international double-blind, placebo-controlled clinical study of NTK in PsA (NCT03598751).A subanalysis was performed to assess the effect of NTK on domains of the 5-level EuroQol 5 Dimensions questionnaire (EQ-5D-5L) in patients with inflammatory back pain (IBP) (IBP(+)) and without (IBP(-)) at baseline according to self-reported ASAS IBP criteria, 2009.194 adult patients with PsA (CASPAR criteria, 2006) with inadequate response to csDMARD or one TNFi, were randomly assigned to receive NTK 120mg or placebo at weeks 0,1,2,4,6,8,10,14,18,22. The proportion of patients reported >1 problem in each domain was evaluated. Patients with missing values were considered as non-responders in the analysis.97 PsA patients (N=54 IBP(+), N=43 IBP(-)) received NTK. The subpopulations didn’t differ significantly in gender, age, and PsA activity at baseline. Comparable percentage of patients reported any problems for each domain at baseline (p≥0.05) (data not shown). IBP(-) subpopulation had a greater improvement for all domains except of anxiety/depression. The absolute declines for IBP(+) vs IBP(-) patients were as followed: 24.1% vs 41.9% (mobility), 18.5 vs 41.9% (self-care), 24.0% vs 51.1% (usual activities), 24.1% vs 37.2% (pain/discomfort), 33.3% vs 9.3% (anxiety/depression). However, the only significant difference between IBP(+) and IBP(-) was observed in usual activity (Figure 1).NTK resulted in the growing improvement of each EQ-5D-5L domain through 24 weeks irrespectively of the presence of IBP. IBP(-) subjects showed trend to greater benefit compared to IBP(+).Figure 1Percentage of patients reported any problems in (A) pain/discomfort, (B) in usual activity at each visitThis study was sponsored by JSC BIOCAD.Inna Gaydukova Speakers bureau: Abbvie, Biocad, Eli Lilly, MSD, Novartis, Pfizer, Sandoz, Tatiana Korotaeva Speakers bureau: Abbvie, Biocad, Eli Lilly, Johnson & Johnson, Janssen, Novartis, Pfizer, UCB, V Mazurov: None declared., Aleksey Samtsov: None declared., Vladislav Khayrutdinov: None declared., Andrey Bakulev: None declared., Alena Kundzer: None declared., Nikolaj Soroka: None declared., Anna Eremeeva Employee of: Biocad.

Background: PATERA is an ongoing phase 3 international double-blind, placebo-controlled clinical study of netakimab (NTK) in psoriatic arthritis (PsA) ( NCT03598751 ). Netakimab (NTK) is an anti-interleukin-17A monoclonal antibody approved for psoriasis, ankylosing spondylitis, PsA in Russia and Belarus. Objectives: A subanalysis was performed to define the impact of NTK on PsA activity depending on the presence of axial disease: a subset of patients with inflammatory back pain (IBP) according to self-reported ASAS IBP criteria, 2009 (IBP(+) was compared to those without IBP (IBP(-)). Methods: 194 eligible adult patients with PsA fulfilling the CASPAR criteria, with inadequate response to csDMARD or one TNFi, were randomly assigned to receive NTK 120mg or placebo at weeks 0,1,2,4,6,8,10,14,18,22. Patients with missing values for categorical variables were considered as non-responders in the analysis. For quantitative variables, missing values were replaced using the multiple imputation method. Results: 97 PsA patients (N=54 IBP(+), N=43 IBP(-)) received NTK. Both subpopulations were comparable in gender, age and PsA activity at baseline. The treatment led to a pronounced decline in PsA activity in both subpopulations, significant differences between arms were observed only in DAPSA remission and very low disease activity (VLDA) at week 24 (Figure 1A). Changes from baseline in DAS28-CRP were consistent between IBP(+) and IBP(-) patients with a rapid decline during the first month with further improvement up to week 24 (Figure 1B). A similar trend was observed PsA-specific composite responder index (PSARC) (data not shown). A comparable percentage of IBP(+) and IBP(-) patients achieved PSARC at each timepoint of evaluation with 87% and 86% of responders respectively at week 24. Conclusion: NTK significantly improved PsA activity regardless of the presence of IBP. Figure 1. PsA activity after 24-week treatment with NTK. (A) Percentage of patients with DAPSA remission (0-4), very low disease activity (VLDA), minimal disease activity (MDA) at week 24; (B) change from baseline in DAS28-CRP Acknowledgements: This study was sponsored by JSC BIOCAD. Disclosure of Interests: Tatiana Korotaeva Speakers bureau: Abbvie, Biocad, Eli Lilly, Johnson & Johnson, Janssen, Novartis, Pfizer, UCB, Inna Gaydukova Speakers bureau: Abbvie, Biocad, Eli Lilly, MSD, Novartis, Pfizer, Sandoz, V Mazurov: None declared, Aleksey Samtsov: None declared, Vladislav Khayrutdinov: None declared, Andrey Bakulev: None declared, Alena Kundzer: None declared, Nikolaj Soroka: None declared, Anna Eremeeva Employee of: Biocad.

Background: Inflammatory back pain (IBP) is a common symptom of axial disease in patients with psoriatic arthritis (PsA). The reported prevalence of axial disease in patients with PsA is quite variable and must be taken into account while choosing treatment strategy. Netakimab (NTK) is an anti-interleukin-17A monoclonal antibody approved for psoriasis, ankylosing spondylitis, PsA in Russia and Belarus. Objectives: A subanalysis was aimed to investigate the ACR (American College of Rheumatology) 20/50/70 response rate in PsA patients with/without the axial disease, defined by the presence of IBP according to self-reported ASAS IBP criteria, 2009 at baseline. Methods: PATERA is an ongoing phase 3 international double-blind, placebo-controlled clinical study ( NCT03598751 ). 194 adult patients with PsA (CASPAR criteria, 2006) with inadequate response to csDMARD or one TNFi, were randomly assigned to receive NTK 120mg or placebo at weeks 0,1,2,4,6,8,10,14,18,22. The ACR response was calculated in NTK-treated patients with IBP (IBP(+)) and NTK-treated patients without IBP (IBP(-)) according to self-reported ASAS IBP criteria, 2009. Patients with missing values for categorical variables were considered as non-responders in the analysis. Results: 97 PsA patients (N=54 IBP(+), N=43 IBP(-)) received NTK. Both subpopulations were comparable in gender, age, and PsA activity at baseline. There were no significant differences in ACR20 achievement between the groups (Figure 1). The percentage of patients with ACR50 was significantly (p<0.05) higher in the IBP(-) subpopulation at weeks 4-20 (data not shown), but not at week 24 with 63% IBP(+) and 79% IBP(-) responders (p≥0.05). Similarly, IBP(+) patients had a lower frequency of ACR70 response (Figure 1). Conclusion: NTK is effective in PsA treatment irrespectively of the presence of axial disease. Both IBP(-) and IBP(+) subpopulations achieved ACR20/50/70 as well, however, the benefit in IBP(-) patients was more pronounced. Figure 1 ACR response rates Acknowledgements: This study was sponsored by JSC BIOCAD. Disclosure of Interests: Tatiana Korotaeva Speakers bureau: Abbvie, Biocad, Eli Lilly, Johnson & Johnson, Janssen, Novartis, Pfizer, UCB, Inna Gaydukova Speakers bureau: Abbvie, Biocad, Eli Lilly, MSD, Novartis, Pfizer, Sandoz, V Mazurov: None declared., Aleksey Samtsov: None declared., Vladislav Khayrutdinov: None declared., Andrey Bakulev: None declared., Alena Kundzer: None declared., Nikolaj Soroka: None declared., Anna Eremeeva Employee of: Biocad.

Background: Psoriatic arthritis (PsA) is associated with multiple manifestations, resulting in reduced health-related quality of life (HR-QoL) of patients (pts). Netakimab (NTK) is a humanized anti-IL17A antibody approved for the treatment of moderate-to-severe plaque psoriasis. Objectives: To assess the impact of NTK on patient-reported outcomes (PROs) in active PsA pts, based on data of 24-week (wk) data from the ongoing PATERA study ( NCT03598751 ). Methods: PATERA is an international double-blind, placebo-controlled clinical study. 194 eligible adult pts with PsA (CASPAR, 2006), with inadequate response to csDMARD or one TNFi, were randomized (1:1) to receive NTK 120 mg or placebo (PBO) at Wk 0, 1, 2, 4, 6, 8, 10, 14, 18, 22. Pts from PBO arm failed to achieve ACR20 (20% improvement of the American College of Rheumatology criteria) by Wk 16 were switched to NTK. PROs included changes from baseline (BL) in Work Productivity and Activity Impairment General Health (WPAI GH), 36-item Short Form Health Survey (SF-36), European Quality of Life Questionnaire (EQ-5D-5L), Dermatology Quality of Life Index (DLQI), Health assessment questionnaire disability index (HAQ-DI). Results: BL demographics and PsA characteristics were similar between treatment arms (Table 1). The proportion of pts with an improvement of ≥1 level in EQ-5D domains at Wk 24 (among pts who reported problems at BL) was higher in NTK arm compared to PBO (Figure 1). The assessment of physical disability showed positive dynamics in NTK arm: at Wk 24 mean change in HAQ-DI from BL was -0.6 for NTK vs -0.1 for PBO (p<0.0001). DLQI was assessed in pts with ≥3% body surface area involvement at BL (N=76 in NTK arm, N=72 in PBO arm). A greater reduction in DLQI was observed in NTK-treated pts (-11.4) compared to PBO-treated pts (-1.8) (p<0.0001). After 24 wks WPAI response for NTK was better than for PBO in all aspects, except work time missed due to PsA (Table 2). Positive dynamics were reported for both SF-36 components, however, the difference between NTK and PBO was not statistically significant. At Wk 24 mean change from baseline in SF-36 PCS in NTK arm was 10.4 vs 7.7 in PBO (p=0.29), mean change in SF-36 MCS was 6.4 vs 9.0 in the same arms, respectively (p=0.56). Table 1. BL demographics and PsA characteristics Arm NTK (N=97 ) PBO (N=97 ) Age (years) * 44.0 (11.7) 43.1 (11.9) Male, n (%) 52 (53.6) 50 (51.6) PsA duration, mo * 63.1 (73.1) 68.2 (77.5) HAQ-DI * 1.15 (0.6) 1.21 (0.6) DLQI * 14.8 (6.5) 13.9 (7.3) SF36 PCS * 32.39 (9.5) 31.10 (8.9) SF36 MCS * 45.29 (10.7) 46.04 (11.5) * mean (standard deviation), N=number of pts, mo=months, PsA=psoriatic arthritis, HAQ-DI=Health assessment questionnaire disability index, DLQI=Dermatology Quality of Life Index, SF36=36-item Short Form Health Survey, MCS=Mental Component Summary, PCS=Physical Component Summary Table 2. WPAI change from BL at wk 24 (mean±standard deviation) Parameter NTK PBO Absenteeism (%) -8.7±29.1 N=60 -9.1±31.8 N=47 Presenteeism (%) -22.1 ±22.1 N=57 -1.0±26.5 N=42 Overall work impairment (%) -18.6±21.8 N=57 0.6±26.7 N=42 Activity impairment (%) -25.5±25.2 N=96 -5.4±29.1 N=97 N=number of pts in the analysis category Figure 1. Improvement in EQ-5D categories Conclusion: NTK demonstrated rapid improvement in QoL, work productivity and physical function in pts with PsA. Acknowledgments: This study was sponsored by JSC BIOCAD. Disclosure of Interests: Tatiana Korotaeva Consultant of: Pfizer, MSD, Novartis, AbbVie, Celgene, JSC BIOCAD, Janssen, UCB, Lilly and Novartis-Sandoz, Speakers bureau: Pfizer, MSD, Novartis, AbbVie, Celgene, JSC BIOCAD, Janssen, UCB, Lilly and Novartis-Sandoz, Inna Gaydukova Grant/research support from: JSC BIOCAD, Speakers bureau: Pfizer, Novartis, AbbVie, JSC BIOCAD, Сelgene, MSD, Sanofi, V Mazurov: None declared, Aleksey Samtsov Grant/research support from: JSC BIOCAD, Novartis, Eli Lilly, Johnson&Johnson, Celgene, Glenmark, Galderma, Sanofi, Vladislav Khayrutdinov Grant/research support from: Akrikhin, Alkoy, Belupo, JSC BIOCAD, Bosnaliejk, Verteks, Glenmark, Elfa, Leo Pharma, MSD, Novartis, Pfizer, Sun Pharma, Sanofi, Celgene, Pharmtec, AbbVie, Eli Lilly, Jadran, Janssen, Andrey Bakulev Grant/research support from: AbbVie, Eli Lilly, Pfizer, UCB, MSD, Novartis, Galderma, Celgene, Leo Pharma and Johnson&Johnson, JSC BIOCAD, Consultant of: Novartis, Celgene and Johnson&Johnson, Speakers bureau: AbbVie, Eli Lilly, Galderma, UCB, Novartis, Celgene and Johnson&Johnson, Muza Kokhan Grant/research support from: AbbVie, Eli Lilly, Pfizer, UCB, MSD, Novartis, Galderma, Celgene, Leo Pharma and Johnson&Johnson, JSC BIOCAD, Consultant of: Novartis, Celgene and Johnson&Johnson, Speakers bureau: AbbVie, Eli Lilly, Galderma, UCB, Novartis, Celgene and Johnson&Johnson, Alena Kundzer: None declared, Nikolaj Soroka Grant/research support from: JSC BIOCAD, Ekaterina Dokukina Employee of: JSC BIOCAD, Anna Eremeeva Employee of: JSC BIOCAD

Background: Patients with psoriatic arthritis (PsA) have skin manifestations that negatively affect their quality of life. Netakimab (NTK) is a humanized anti-interleukin 17A antibody approved for the treatment of moderate-to-severe plaque psoriasis. Objectives: To evaluate the efficacy of NTK on PsA skin manifestations. This abstract presents 24-week data from the ongoing phase 3 PATERA study ( NCT03598751 ). Methods: PATERA is an international, multicenter, double-blind, placebo (PBO)-controlled study. 194 eligible adult patients with psoriatic arthritis (CASPAR, 2006), with inadequate response to csDMARD or one TNFi, were randomly assigned (1:1) to receive NTK 120 mg or placebo (PBO) subcutaneously at Week (Wk) 0, 1, 2, 4, 6, 8, 10, 14, 18, 22. 84 patients from PBO arm, failed to achieve ACR20 (20% improvement in American College of Rheumatology criteria) at Wk 16, were switched to NTK. Endpoints for assessment of skin involvement included PASI the proportion of patients achieving 75%, 90%, and 100% improvement in Psoriasis Area and Severity Index score (PASI75, PASI90 and PASI100, respectively). Results: 184 patients (NTK arm, N=94; PBO arm, N=90) had PASI>0 at baseline (BL). Demographics and BL characteristics were balanced between treatment arms (Table 1). Treatment response was assessed in patients with ≥3% body surface area involvement (BSA) at BL. PASI75/90/100 response rates for NTK arm were significantly greater than for PBO and increased throughout the whole analyzed period. At Wk 24 PASI75 was achieved by 82.89% vs 11.11% for NTK and PBO, respectively (p<0.0001). A significantly higher percentage of patients achieved complete skin clearance (PASI100) in NTK arm compared to PBO (48.68% vs 6.94%, p<0.0001). PASI90 response rate was also higher for NTK (Figure 1). Relative change (%) from baseline in PASI score correlated with PASI75/90/100 response rates throughout the entire analyzed period. PASI decreased by 87.5 % in NTK arm vs only 4.4% in PBO arm after 24 wks of treatment (Table 2). Table 1. BL characteristics (for patients with PASI>0 at BL) Arm NTK (N=94) PBO (N=90) Age (years) * 44.0 (11.82) 42.9 (12.14) Male, n (%) 51 (54.26) 48 (53.33) PsA duration, mo * 63.3 (73.81) 68.1 (79.79) PASI * 12.27 (11.31) 10.35 (9.80) * mean (standard deviation); mo=months, PASI=Psoriasis Area and Severity Index Table 2. Percentage (%) change from baseline in PASI total score (mean (SD)) NTK (N=76) PBO (N=72) Week 4* -61.1 (36.04) -8.6 (31.99) Week 8* -74.2 (35.36) -8.4 (37.57) Week 16* -80.8 (49.38) -2.3 (61.06) Week 24* -87.5 (32.83) -4.4 (63.48) Data are presented for patients with BL BSA ≥ 3%; *p<0.0001 vs placebo Figure 1. Percentage of patients with PASI75/90/100 at Wk 24 (in patients with BL BSA≥3) Conclusion: 24-week treatment with NTK at the dose of 120 mg resulted in significant improvement in skin manifestations in PsA patients: more than half of the patients with BSA≥3 at BL achieved complete skin clearance. Acknowledgments: This study was sponsored by JSC BIOCAD. Disclosure of Interests: Tatiana Korotaeva Consultant of: Pfizer, MSD, Novartis, AbbVie, Celgene, JSC BIOCAD, Janssen, UCB, Lilly and Novartis-Sandoz, Speakers bureau: Pfizer, MSD, Novartis, AbbVie, Celgene, JSC BIOCAD, Janssen, UCB, Lilly and Novartis-Sandoz, Inna Gaydukova Grant/research support from: JSC BIOCAD, Speakers bureau: Pfizer, Novartis, AbbVie, JSC BIOCAD, Сelgene, MSD, Sanofi, V Mazurov: None declared, Aleksey Samtsov Grant/research support from: JSC BIOCAD, Novartis, Eli Lilly, Johnson&Johnson, Celgene, Glenmark, Galderma, Sanofi, Vladislav Khayrutdinov Grant/research support from: Akrikhin, Alkoy, Belupo, JSC BIOCAD, Bosnaliejk, Verteks, Glenmark, Elfa, Leo Pharma, MSD, Novartis, Pfizer, Sun Pharma, Sanofi, Celgene, Pharmtec, AbbVie, Eli Lilly, Jadran, Janssen, Andrey Bakulev Grant/research support from: AbbVie, Eli Lilly, Pfizer, UCB, MSD, Novartis, Galderma, Celgene, Leo Pharma and Johnson&Johnson, JSC BIOCAD, Consultant of: Novartis, Celgene and Johnson&Johnson, Speakers bureau: AbbVie, Eli Lilly, Galderma, UCB, Novartis, Celgene and Johnson&Johnson, Muza Kokhan Grant/research support from: AbbVie, Eli Lilly, Pfizer, UCB, MSD, Novartis, Galderma, Celgene, Leo Pharma and Johnson&Johnson, JSC BIOCAD, Consultant of: Novartis, Celgene and Johnson&Johnson, Speakers bureau: AbbVie, Eli Lilly, Galderma, UCB, Novartis, Celgene and Johnson&Johnson, Alena Kundzer: None declared, Nikolaj Soroka Grant/research support from: JSC BIOCAD, Ekaterina Dokukina Employee of: JSC BIOCAD, Anna Eremeeva Employee of: JSC BIOCAD

Background: The presence of axial involvement significantly impacts on psoriatic arthritis (PsA) activity, outcomes and patients (pts) quality of life. IL-17A inhibitors were previously shown to improve axial disease in PsA. Netakimab (NTK) is a humanized anti-interleukin 17A antibody approved for the treatment of moderate-to-severe plaque psoriasis. Objectives: To evaluate the effects of NTK on axial symptoms in patients with PsA, based on data of 24-week (wk) observation from an ongoing phase 3 PATERA study ( NCT03598751 ). Methods: PATERA is a phase 3 international double-blind, placebo-controlled clinical study. After completion of screening 194 eligible adult patients with PsA fulfilling the CASPAR criteria, with inadequate response to csDMARD or one TNFi, were randomly assigned (1:1) to receive NTK 120 mg or placebo (PBO) at Wks 0, 1, 2, 4, 6, 8, 10, 14, 18 and 22. 84 patients from PBO arm, failed to achieve ACR20 (20% improvement the American College of Rheumatology criteria) by Wk 16, were switched to NTK. A subset of pts with axial involvement (defined by presence of inflammatory back pain (IBP) according to ASAS IBP criteria, 2009) was evaluated with spondylitis-specific assessments: spinal pain (10-item numerical rating scale), nocturnal back pain (10-item numerical rating scale), BASDAI (Bath Ankylosing Spondylitis Disease Activity Index), ASDAS-CRP (Ankylosing Spondylitis Disease Activity Score with C-reactive protein. Results: 104 PsA patients (NTK N=54, PBO N=50) with IBP at baseline (BL) were included in the analysis. Demographic and BL disease characteristics were comparable across the groups (Table 1). During the analyzed period, BASDAI and ASDAS-CRP scores significantly decreased in NTK-treated patients (Figure 1). Maximum decrease in axial disease activity developed by Wk 4-8 depending on index of assessment. The achieved values maintained throughout the entire analyzed period (Table 2). At Wk 24, mean changes in ASDAS-CRP and BASDAI were -1.57 and -2.83 in NTK arm vs -0.11 and -0.19 in PBO arm respectively (p<0.0001). Table 1. Baseline demographics and mean composite endpoint scores Arm NTK (N=54) PBO (N=50) Age (years) * 43.5 (12.16) 42.7 (10.76) Male, n (%) 27 (50) 26 (52) PsA duration, mo * 70.0 (78.78) 79.0 (81.62) BASDAI score * 5.58 (1.80) 5.79 (1.94) ASDAS-CRP score * 3.38 (1.16) 3.38 (1.28) nocturnal pain * 4.2 (2.42) 5.1 (2.29) spinal pain * 4.4 (2.41) 5.3 (2.40) * mean (standard deviation) BASDAI=Bath Ankylosing Spondylitis Disease Activity Index, ASDAS-CRP=Ankylosing Spondylitis Disease Activity Score with C-reactive protein Table 2. Changes in BASDAI and ASDAS-CRP vs baseline BASDAI ASDAS-CRP NTK (N=54) PBO (N=50) NTK (N=54) PBO (N=50) Wk 4 -2.45 (1.94) -0.51 (1.26) -1.44 (1.06) -0.19 (0.60) Wk 8 -2.77 (2.22) -0.38 (1.55) -1.53 (1.07) -0.21 (0.74) Wk 16 -2.77 (1.83) -0.17 (1.67) -1.52 (0.98) -0.10 (0.97) Wk 24 -2.83 (2.15) -0.19 (1.70) -1.57 (1.06) -0.11 (0.95) mean (standard deviation) Figure 1. Mean change in BASDAI, ASDAS-CRP, spinal pain, and nocturnal pain at Wk 24 Conclusion: About 50% of subjects, randomized to PATERA study, had IBP at baseline. NTK leads to rapid and sustained improvement in axial disease in patients with active PsA. Acknowledgments: This study was sponsored by JSC BIOCAD. Disclosure of Interests: Tatiana Korotaeva Grant/research support from: Pfizer, Consultant of: Abbvie, BIOCAD, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Novartis-Sandoz, Pfizer, UCB, Speakers bureau: Abbvie, BIOCAD, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Novartis-Sandoz, Pfizer, UCB, Inna Gaydukova Grant/research support from: JSC BIOCAD, Speakers bureau: Pfizer, Novartis, AbbVie, JSC BIOCAD, Сelgene, MSD, Sanofi, V Mazurov: None declared, Aleksey Samtsov Grant/research support from: JSC BIOCAD, Novartis, Eli Lilly, Johnson&Johnson, Celgene, Glenmark, Galderma, Sanofi, Vladislav Khayrutdinov Grant/research support from: Akrikhin, Alkoy, Belupo, JSC BIOCAD, Bosnaliejk, Verteks, Glenmark, Elfa, Leo Pharma, MSD, Novartis, Pfizer, Sun Pharma, Sanofi, Celgene, Pharmtec, AbbVie, Eli Lilly, Jadran, Janssen, Andrey Bakulev Grant/research support from: AbbVie, Eli Lilly, Pfizer, UCB, MSD, Novartis, Galderma, Celgene, Leo Pharma and Johnson&Johnson, JSC BIOCAD, Consultant of: Novartis, Celgene and Johnson&Johnson, Speakers bureau: AbbVie, Eli Lilly, Galderma, UCB, Novartis, Celgene and Johnson&Johnson, Muza Kokhan Grant/research support from: AbbVie, Eli Lilly, Pfizer, UCB, MSD, Novartis, Galderma, Celgene, Leo Pharma and Johnson&Johnson, JSC BIOCAD, Consultant of: Novartis, Celgene and Johnson&Johnson, Speakers bureau: AbbVie, Eli Lilly, Galderma, UCB, Novartis, Celgene and Johnson&Johnson, Alena Kundzer: None declared, Nikolaj Soroka Grant/research support from: JSC BIOCAD, Ekaterina Dokukina Employee of: JSC BIOCAD, Anna Eremeeva Employee of: JSC BIOCAD

Background: Netakimab (NTK) is a humanized anti-interleukin 17A antibody approved for the treatment of moderate-to-severe plaque psoriasis. Objectives: To determine the efficacy and safety of NTK in patients (pts) with active psoriatic arthritis (PsA), based on 24-week (Wk) data from an ongoing phase 3 study ( NCT03598751 , PATERA). Methods: 194 eligible adult pts with PsA (CASPAR, 2006) with inadequate response to csDMARD or one TNFi, were randomized (1:1) to receive NTK 120 mg or placebo (PBO) subcutaneously at Wk 0, 1, 2, 4, 6, 8, 10, 14, 18, 22. 84 pts from PBO arm who did not meet ACR20 (20% improvement of the American College of Rheumatology criteria) by Wk 16 were switched to NTK 120 mg. The primary endpoint was AСR20 at Wk 24. DAPSA (Disease Activity Index for Psoriatic Arthritis), the proportion of pts achieved ACR50/70, minimal disease activity (MDA) (≥5/7 MDA criteria) and Psoriatic arthritis response criteria (PsARC) were also analyzed. Results: Baseline demographics and disease characteristics were similar across treatment arms (Table 1). 80 (82.47%) pts in NTK arm and 9 (9.28%) in the PBO arm achieved ACR20 at Wk 24 (р<0.0001). A significantly greater percentage of NTK-treated pts had ACR50/70, PsARC response, MDA at Wk 24 (Figure 1). By Wk 24 DAPSA significantly improved for NTK vs PBO. DAPSA remission was achieved by 36.08% and 13.40% in NTK and PBO arms, respectively (p=0.003). NTK was well tolerated. The most frequent AEs (≥3%) were lymphopenia, neutropenia, hypercholesterolemia, ALT increased, upper respiratory tract infection, systolic blood pressure increased, hyperglycemia, hyperbilirubinemia. Most AEs were mild to moderate. Severe treatment-related AEs were observed in 1.03% vs 2.06% for NTK and PBO, respectively. No treatment-related SAEs were reported. No anti-drug antibodies were detected. Table 1. Baseline demographics and disease severity characteristics Arm NTK (N=97 ) PBO (N=97 ) Age (years) * 44.0 (11.66) 43.1 (11.88) Male, n (%) 52 (53.61) 50 (51.55) PsA duration, mo* 63.1 (73.12) 68.2 (77.49) DAS28-CRP* 4.62 (0.97) 4.41 (1.11) DAPSA* 32.19 (12.23) 33.54 (15.98) TJC (66/68) * 12.9 (9.97) 12.0 (9.88) SJC (66/68) * 7.0 (4.93) 7.2 (7.18) MTX at baseline 83 (85.6) 83 (85.6) Previous PsA therapy Sulfasalazine, n (%) 9 (9.28) 11 (11.34) Leflunomide, n (%) 4 (4.12) 8 (8.25) Anti-TNFα, n (%) 22 (22.68) 17 (17.53) * mean (standard deviation); Mo=months, PsA=psoriatic arthritis, SJC=swollen joint count, TJC=tender joint count, DAS28=Disease Activity Score, MTX=methotrexate, CRP=C-reactive protein, DAPSA=Disease activity index for psoriatic arthritis, TNF=tumor necrosis factor Figure 1. Treatment response at Wk 24 Conclusion: NTK is a well-tolerated monoclonal antibody, that provided sustained improvements in signs and symptoms of active PsA through 24 Wks of therapy. Table 2. Safety data Arm NTK (N=97) PBO (N=97) p-value Treatment-related AEs 12 (12.37) 7 (7.22) 0.227 1 Treatment-related SAEs 0 (0) 0 (0) 1.00 2 Treatment-related AEs (grade 3-4) 1 (1.03) 2 (2.06) 1.00 2 Local reactions 0 (0) 0 (0) - Grade 3-4 treatment-related AEs blood pressure increased 1 (1.03) 0(0) 1.00 2 lymphopenia 0 (0) 2 (2.06) 0.497 2 n (%) are presented, 1 Pearson’s χ 2 test, 2 Fisher’s exact test; N=number of patients, AE=adverse event, SAE=serious adverse event, ALT=Alanine transaminase Acknowledgments: This study was sponsored by JSC BIOCAD. Disclosure of Interests: Tatiana Korotaeva Consultant of: Pfizer, MSD, Novartis, AbbVie, Celgene, JSC BIOCAD, Janssen, UCB, Lilly and Novartis-Sandoz, Speakers bureau: Pfizer, MSD, Novartis, AbbVie, Celgene, JSC BIOCAD, Janssen, UCB, Lilly and Novartis-Sandoz, Inna Gaydukova Grant/research support from: JSC BIOCAD, Speakers bureau: Pfizer, Novartis, AbbVie, JSC BIOCAD, Сelgene, MSD, Sanofi, V Mazurov: None declared, Aleksey Samtsov Grant/research support from: JSC BIOCAD, Novartis, Eli Lilly, Johnson&Johnson, Celgene, Glenmark, Galderma, Sanofi, Vladislav Khayrutdinov Grant/research support from: Akrikhin, Alkoy, Belupo, JSC BIOCAD, Bosnaliejk, Verteks, Glenmark, Elfa, Leo Pharma, MSD, Novartis, Pfizer, Sun Pharma, Sanofi, Celgene, Pharmtec, AbbVie, Eli Lilly, Jadran, Janssen, Andrey Bakulev Grant/research support from: AbbVie, Eli Lilly, Pfizer, UCB, MSD, Novartis, Galderma, Celgene, Leo Pharma and Johnson&Johnson, JSC BIOCAD, Consultant of: Novartis, Celgene and Johnson&Johnson, Speakers bureau: AbbVie, Eli Lilly, Galderma, UCB, Novartis, Celgene and Johnson&Johnson, Muza Kokhan Grant/research support from: AbbVie, Eli Lilly, Pfizer, UCB, MSD, Novartis, Galderma, Celgene, Leo Pharma and Johnson&Johnson, JSC BIOCAD, Consultant of: Novartis, Celgene and Johnson&Johnson, Speakers bureau: AbbVie, Eli Lilly, Galderma, UCB, Novartis, Celgene and Johnson&Johnson, Alena Kundzer: None declared, Nikolaj Soroka Grant/research support from: JSC BIOCAD, Ekaterina Dokukina Employee of: JSC BIOCAD, Anna Eremeeva Employee of: JSC BIOCAD