Background:Rituximab (RTX) is a monoclonal antibody against the CD20 B cell antigen that has been used successfully in recent years for the treatment of rheumatoid arthritis (RA). It is an effective drug that reaches survival rates of 60% at 5 years of treatment as reflected in the British experience. However, survival in Spanish patients is unknown.Objectives:To study the survival of RTX treatment and the characteristics of patients with RA treated with the drug since its commercialization in Spain.Methods:Observational, retrospective and analytical study of a cohort of patients with RA treated with at least one dose of RTX. We reviewed the medical records of all patients with RA from January 2007 to June 2017. A total of 178 previous defined variables were collected, highlighting data about treatment (use of RTX, associated conventional synthetic disease modifying drugs [FAMEsc], doses of corticosteroids [GC] used) and activity indices. Descriptive statistics were performed (median and the 25th and 75th percentiles are shown). The comparative analysis was done with χ2 and U of Mann Whitney for categorical variables and paired sign rank test or Student’s t for continuous. Survival Kaplan Mayer curves were constructed. The study was carried out in accordance with the standards of our Clinical Research Ethics Committee.Results:A total of 54 patients were analyzed. 74% (n = 40) of them were women, the age was 61.2 years (51.0 - 67.4). 74% (n = 40) presented some type of relevant comorbidity. Its RA was FR + in 96% (n = 52) and ACCP + in 78% (n = 42) of the cases, with an evolution time of 9.3 years (3.5-19, 2), and with radiographic erosions in up to 63% (n = 34). At the time of the start of the RTX, 100% of the patients (n = 54) received some FAMEsc, and 33 (61%) were treated with prednisone; the daily dose of prednisone was 9 (6-12) mg. The baseline DAS28-VSG was 5 (4.1 - 6.0). The duration of the follow-up was 56.6 (29.3-92.1) months. Patients received a mean of 5 (1-6) cycles of RTX at a dose of 1000 mg on days 0 and 15 in most cases. The final DAS28-VSG was 2.6 (2.1 - 4.0), p = 0.00001 compared to baseline. The delta between baseline and final DAS was -2.36 (-0.55 - -3.1). At the end of the RTX treatment, the EULAR response rate was good in 64% (n = 25), reaching remission in 17 (31%) of the patients, and moderate response in 21% (n = 8) of them (Figure 1). Only 2 (4%) patients were treated with GCC at the end of the follow-up, p<0,00001 compared to baseline. The daily dose of PDN at the end of follow-up was 6 mg in a case and 12 mg in the other, p=00001 compared to baseline. At the end of the follow-up 24%of the patients (n = 13) changed or discontinued the drug: 9 changed due to secondary failure, 2 suspended due to adverse events, 1 due to death due to prior neoplastic process and 1 due to complete disease remission. Survival at 1, 2, 3, 4, 5, 6 and 7 years was 92%, 92%, 82% 78%, 75%, 75% and 65% respectively; with a mean survival rate of 90 months (Figure 1).Conclusion:The results of our analysis show that patients with RA undergoing RTX treatment have adequate control of disease activity and drug survival rates, like published data. RTX treatment allowed stopped GCC treatment in 31 cases (90%).References:[1]Oldroyd AGS, et al. Rheumatology (Oxford). 2018 Jun 1;57(6):1089-1096.Disclosure of Interests:Gonzalo Jurado Quijano: None declared, Lola Fernández de la Fuente Bursón: None declared, Blanca Hernández-Cruz Speakers bureau: Sociedad Española de Reumatología, Abbvie, Roche, Bristol, MSD, Lilly, Pfizer, Amgen, Sanofi, Consultant of: Abbvie, Lilly, Sanofi, STADA, UCB, Amgen, Grant/research support from: Fundación para la Investigación Sevilla, Junta de Andalucía, Fundación Andaluza de Reumatología, Paloma Muñoz Reinoso: None declared, Vicente Merino Bohóquez: None declared, José Javier Pérez Venegas: None declared
Dirichlet-multinomial modelling outperforms alternatives for analysis of microbiome and other ecological count data