title: Monitoring drug and antidrug levels: a rational approach in rheumatoid arthritis patients treated with biologic agents who experience inadequate response while being on a stable biologic treatment.
abstract: Clinical response in patients with rheumatoid arthritis (RA) treated with biologic agents can be influenced by their pharmacokinetics and immunogenicity. The present study evaluated the concordance between serum drug and antidrug levels as well as the clinical response in RA patients treated with biological agents who experience their first disease exacerbation while being on a stable biologic treatment. 154 RA patients treated with rituximab (RTX), infliximab (IFX), adalimumab (ADL), or etanercept (ETN) were included. DAS28, SDAI, and EULAR response were assessed at baseline and reevaluated at precise time intervals. At the time of their first sign of inadequate response, patients were tested for both serum drug level and antidrug antibodies level. At the next reevaluation, patients retreated with RTX that had detectable drug level had a better EULAR response (P = 0.038) with lower DAS28 and SDAI scores (P = 0.01 and P = 0.03). The same tendency was observed in patients treated with IFX and ETN regarding EULAR response (P = 0.002 and P = 0.023), DAS28 score (P = 0.002 and P = 0.003), and SDAI score (P = 0.001 and P = 0.026). Detectable biologic drug levels correlated with a better clinical response in patients experiencing their first RA inadequate response while being on a stable biologic treatment with RTX, IFX, and ETN.
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Diana
authors: D
authors: Mazilu
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Daniela
authors: D
authors: Opriş
authors: "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Cecilia
authors: C
authors: Gainaru
authors: "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Mihaela
authors: M
authors: Iliuta
authors: Biology Faculty, Bucharest University, Bucharest, Romania.
authors: Natalia
authors: N
authors: Apetrei
authors: Biology Faculty, "Alexandru Ioan Cuza" University, Iasi, Romania.
authors: Giorgiana
authors: G
authors: Luca
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Andreea
authors: A
authors: Borangiu
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania.
authors: Tania
authors: T
authors: Gudu
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania.
authors: Alexandra
authors: A
authors: Peltea
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Laura
authors: L
authors: Groseanu
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Cosmin
authors: C
authors: Constantinescu
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Ioana
authors: I
authors: Saulescu
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Violeta
authors: V
authors: Bojinca
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Andra
authors: A
authors: Balanescu
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Denisa
authors: D
authors: Predeteanu
authors: Department of Rheumatology and Internal Medicine, "Sfanta Maria" Hospital, Bulevardul Ion Mihalache nr 37-39, 011172 Bucharest, Romania ; "Carol Davila" University of Medicine, Bucharest, Romania.
authors: Ruxandra
authors: R
authors: Ionescu
mesh_terms: D000906:Antibodies / Q000276:immunology; D018501:Antirheumatic Agents / Q000097:blood / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000188:drug therapy* / Q000276:immunology; D001688:Biological Products / Q000627:therapeutic use*; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring; D006801:Humans; D016896:Treatment Outcome
chemical_list: D000906:Antibodies; D018501:Antirheumatic Agents; D001688:Biological Products