Clinicogenomic factors of biotherapy immunogenicity in autoimmune disease: A prospective multicohort study of the ABIRISK consortium.

BACKGROUND: Biopharmaceutical products (BPs) are widely used to treat autoimmune diseases, but immunogenicity limits their efficacy for an important proportion of patients. Our knowledge of patient-related factors influencing the occurrence of antidrug antibodies (ADAs) is still limited. METHODS AND FINDINGS: The European consortium ABIRISK (Anti-Biopharmaceutical Immunization: prediction and analysis of clinical relevance to minimize the RISK) conducted a clinical and genomic multicohort prospective study of 560 patients with multiple sclerosis (MS, n = 147), rheumatoid arthritis (RA, n = 229), Crohn's disease (n = 148), or ulcerative colitis (n = 36) treated with 8 different biopharmaceuticals (etanercept, n = 84; infliximab, n = 101; adalimumab, n = 153; interferon [IFN]-beta-1a intramuscularly [IM], n = 38; IFN-beta-1a subcutaneously [SC], n = 68; IFN-beta-1b SC, n = 41; rituximab, n = 31; tocilizumab, n = 44) and followed during the first 12 months of therapy for time to ADA development. From the bioclinical data collected, we explored the relationships between patient-related factors and the occurrence of ADAs. Both baseline and time-dependent factors such as concomitant medications were analyzed using Cox proportional hazard regression models. Mean age and disease duration were 35.1 and 0.85 years, respectively, for MS; 54.2 and 3.17 years for RA; and 36.9 and 3.69 years for inflammatory bowel diseases (IBDs). In a multivariate Cox regression model including each of the clinical and genetic factors mentioned hereafter, among the clinical factors, immunosuppressants (adjusted hazard ratio [aHR] = 0.408 [95% confidence interval (CI) 0.253-0.657], p < 0.001) and antibiotics (aHR = 0.121 [0.0437-0.333], p < 0.0001) were independently negatively associated with time to ADA development, whereas infections during the study (aHR = 2.757 [1.616-4.704], p < 0.001) and tobacco smoking (aHR = 2.150 [1.319-3.503], p < 0.01) were positively associated. 351,824 Single-Nucleotide Polymorphisms (SNPs) and 38 imputed Human Leukocyte Antigen (HLA) alleles were analyzed through a genome-wide association study. We found that the HLA-DQA1*05 allele significantly increased the rate of immunogenicity (aHR = 3.9 [1.923-5.976], p < 0.0001 for the homozygotes). Among the 6 genetic variants selected at a 20% false discovery rate (FDR) threshold, the minor allele of rs10508884, which is situated in an intron of the CXCL12 gene, increased the rate of immunogenicity (aHR = 3.804 [2.139-6.764], p < 1 × 10-5 for patients homozygous for the minor allele) and was chosen for validation through a CXCL12 protein enzyme-linked immunosorbent assay (ELISA) on patient serum at baseline before therapy start. CXCL12 protein levels were higher for patients homozygous for the minor allele carrying higher ADA risk (mean: 2,693 pg/ml) than for the other genotypes (mean: 2,317 pg/ml; p = 0.014), and patients with CXCL12 levels above the median in serum were more prone to develop ADAs (aHR = 2.329 [1.106-4.90], p = 0.026). A limitation of the study is the lack of replication; therefore, other studies are required to confirm our findings. CONCLUSION: In our study, we found that immunosuppressants and antibiotics were associated with decreased risk of ADA development, whereas tobacco smoking and infections during the study were associated with increased risk. We found that the HLA-DQA1*05 allele was associated with an increased rate of immunogenicity. Moreover, our results suggest a relationship between CXCL12 production and ADA development independent of the disease, which is consistent with its known function in affinity maturation of antibodies and plasma cell survival. Our findings may help physicians in the management of patients receiving biotherapies.

Endoscopic ultrasound for perianal Crohn's disease: disease and fistula characteristics, and impact on therapy.

BACKGROUND AND AIM: Appropriate treatment of perianal fistulas in Crohn's disease (CD) involves accurate anatomic evaluation. EUS is an accepted imaging method for this purpose. The aim of the current study was to evaluate the clinical and endosonographic characteristics of perianal fistula in CD and to assess its impact on therapy. METHODS: All CD patients referred to the Sheba medical center from June 2004 to August 2008 for EUS examination of perianal fistulas were included. Perianal fistulas were diagnosed based on a clinical examination revealing at least one perianal cutaneous orifice. Demographic, clinical and therapeutic data was obtained. EUS was performed using an ultrasound scanner producing a 360° cross sectional image of the anal sphincters. RESULTS: Fifty six patients were included in the study. Four patients were excluded from the final analysis: 3 because no fistula could be detected by EUS, and one due to inability to tolerate the examination. The mean CD duration was 10±9.16 years (range 1-37). Mean perianal disease duration was 5.3±6.5 (range 1-29) years. 27 patients had perianal involvement at presentation. Among the fistulas diagnosed, 13 were simple (25%) and 39 were (75%) complex. No correlation was found between CD duration or location, patients' age and gender or fistula location with fistula type or complexity. EUS results influenced patient management in 86% of the patients. CONCLUSIONS: CD-associated perianal fistulas are mainly complex. EUS is a well tolerated and informative imaging modality, with significant impact on treatment.

Budesonide foam vs. hydrocortisone acetate foam in the treatment of active ulcerative proctosigmoiditis.

INTRODUCTION: Rectal administration of corticosteroids is advocated in patients with proctosigmoiditis who have failed therapy with mesalamine enema. Foam offers patients better tolerability than an enema. In this study the efficacy and adverse effects of a new budesonide foam are compared with the presently available hydrocortisone foam. METHODS: Two hundred fifty-one patients with proctosigmoiditis were randomly assigned to receive either budesonide foam or hydrocortisone foam for eight weeks. RESULTS: Remission rates were comparable in the budesonide and hydrocortisone groups, 53 and 52 percent, respectively. The mean disease activity index for the two groups decreased to a similar extent, from 7.2 +/- 1.9 and 7 +/- 2 to 3.6 +/- 3.1 and 3.9 +/- 3.4 in the budesonide and hydrocortisone groups, respectively. In a subgroup of patients who had not responded to rectal administration of mesalamine, 23 of 44 (52 percent) patients who received budesonide responded favorably to the foam, as compared with 14 of 38 (37 percent) patients who received hydrocortisone (P = not significant). Low plasma cortisol occurred in 3 percent of the budesonide group and in none of the hydrocortisone patients. CONCLUSIONS: This trial demonstrates a similar efficacy and safety of the two foams in patients with proctosigmoiditis.