Abstract Background Certolizumab pegol (CZP) treatment has been shown to significantly improve work and household productivity and social participation compared to placebo in active non-radiographic axial spondyloarthritis (nr-axSpA) patients up to 24 weeks. Here, we report the impact of CZP in combination with non-biologic background medication (NBBM) on signs and symptoms of nr-axSpA compared to placebo+NBBM. Methods C-axSpAnd (NCT02552212) is a 3-year, phase 3, multicentre study including a 52-week double-blind, placebo-controlled period (completed). Patients had active nr-axSpA, objective signs of inflammation (OSI; elevated CRP and/or positive MRI of the sacroiliac joint), previous inadequate response to ≥ 2 NSAIDs and were randomised 1:1 to CZP (400 mg at Weeks 0/2/4, then 200 mg every 2 weeks) or placebo. The validated arthritis-specific Work Productivity Survey (WPS) assessed the impact of nr-axSpA on work and household productivity and social participation. Missing data were imputed using last observation carried forward (LOCF) post hoc in the Full Analysis Set (randomised patients who received ≥1 dose of CZP). Results 317 patients were randomised (CZP: 159; placebo: 158). Mean age at baseline was 37.3 years and 51.4% of patients were female. At baseline, most patients were employed (CZP: 124 [77.8%]; placebo: 123 [78.0%]) and reported a mean 3.7 (CZP) and 3.5 (placebo) workdays missed per month due to disease (Table 1). By Week 12, work absenteeism substantially improved in the CZP group compared with placebo (0.9 vs 2.1 days missed per month, LOCF), with further improvements at Week 52 (0.3 vs 2.0 days missed per month, LOCF). Between Week 12 and Week 52, most placebo patients (104, 65.8%) switched to open-label CZP, impacting Week 52 imputed outcomes. Despite this, similar patterns of improvement following CZP treatment were seen for absenteeism, workdays with impaired productivity, household days with missed/reduced productivity and social participation between imputed and observed case data (Table 1). Improvements were similar between male and female patients (data not shown). Conclusion CZP treatment resulted in improvements in work and household productivity and social participation for nr-axSpA patients as early as Week 12 compared to background medication only, with benefits maintained to Week 52. Disclosures K. Gaffney: Other; Research Grants/Consultancy Fees from Abbvie, Biogen, Celgene, Gilead, Izana, Janssen, Lilly, Novartis, Pfizer, UCB Pharma. A. Deodhar: Consultancies; AbbVie, Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Eli Lilly, Glaxo Smith and Klein, Janssen, Novartis, Pfizer and UCB. Grants/research support; BMS, Eli Lilly, Glaxo Smith & Kline, Janssen, Novartis, Pfizer and UCB. L. Gensler: Consultancies; Galapagos, Eli Lilly and Janssen. Grants/research support; AbbVie, Amgen, Novartis, UCB Pharma. J. Kay: Consultancies; AbbVie, Boehringer Ingelheim, Celltrion Healthcare, Horizon Therapeutics, Merck Sharp & Dohme, MorphoSys, Novartis, Pfizer, Samsung Bioepis, Sandoz and UCB Pharma. Grants/research support; Gilead Sciences, Novartis AG, Pfizer and UCB Pharma. W. Maksymowych: Other; Consultant and/or speaker fees and/or grants from AbbVie, Amgen, Eli Lilly, Janssen, Merck, Pfizer, Synarc, Sanofi and UCB Pharma. N. Haroon: Consultancies; Abbvie, Amgen, Eli Lilly, Janssen, Novartis and UCB Pharma. R. Landewé: Consultancies; Abbott, Ablynx, Amgen, Astra-Zeneca, Bristol Myers Squibb, Centocor, GlaxoSmithKline, Novartis, Merck, Pfizer, Roche, Schering-Plough, UCB Pharma, Wyeth. Member of speakers’ bureau; Abbott, Amgen, Bristol Myers Squibb, Centocor, Merck, Pfizer, Roche, Schering-Plough, UCB Pharma, Wyeth. Grants/research support; Abbott, Amgen, Centocor, Novartis, Pfizer, Roche, Schering-Plough, UCB Pharma, Wyeth. M. Rudwaleit: Consultancies; Abbott, Bristol-Myers Squibb, Janssen, MSD, Pfizer, Roche, UCB Pharma. S. Hall: Other; Consulting fees/ research grants from AbbVie, Eli Lilly, Novartis, and UCB Pharma. L. Bauer: Other; Employee of UCB Pharma. B. Hoepken: Other; Employee of UCB Pharma. N. de Peyrecave: Other; Employee of UCB Pharma. T. Kumke: Other; Employee of UCB Pharma. D. van der Heijde: Consultancies; AbbVie, Amgen, Astellas, AstraZeneca, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Daiichi, Eli Lilly, Galapagos, Gilead, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, and UCB. Other; Director of Imaging Rheumatology BV.