Higher Adalimumab Trough Levels Are Associated with Histologic Remission and Mucosal Healing in Inflammatory Bowel Disease.

(1) Many patients with inflammatory bowel disease (IBD) in endoscopic remission have persistent histologic activity, which is associated with worse outcomes. There are limited data on the association between adalimumab drug concentrations and histologic outcomes using validated histologic indices. We aimed to assess the relationship between adalimumab concentrations and the Robarts Histopathology Index (RHI). (2) Patients from a tertiary IBD center from 2013 to 2020 with serum adalimumab (ADA) trough concentrations measured during maintenance therapy (≥14 weeks) and a colonoscopy or flexible sigmoidoscopy with biopsies performed within 90 days of drug level were included. Blinded histologic scoring using the RHI was performed. Primary analysis assessed the relationship between adalimumab drug concentrations and histologic remission using receiver operating characteristic curve analysis. (3) In 36 patients (26 Crohn's Disease, 9 ulcerative colitis, 1 indeterminate), median adalimumab concentrations were higher (17.3 ug/mL, 12.2-24.0) in patients with histologic remission compared to those without (10.3 ug/mL, 6.8-13.9, p = 0.008). The optimal ADA concentration identified using the Youden threshold was ≥16.3 ug/mL (sensitivity 70%, specificity 90%). Patients with ADA ≥ 16.3 ug/mL had higher histologic remission rates (78%) compared to lower ADA concentrations (14%, p= 0.002), as well as higher mucosal healing rates (86%) compared to lower levels (12%, p = 0.001). Symptoms correlated weakly and non-significantly with both histologic (RHI) scores (r = 0.25, p = 0.2) and adalimumab concentrations (r = 0.05, p = 0.8). (4) The current study demonstrated that higher serum adalimumab concentrations (≥16.3 ug/mL) are needed for histologic remission and mucosal healing assessed using the RHI.

The Relationship Between the Endoscopic Healing Index, Fecal Calprotectin, and Magnetic Resonance Enterography in Crohn's Disease.

INTRODUCTION: The serum-based endoscopic healing index (EHI) test identifies endoscopic Crohn's disease (CD) activity. Data are lacking on the relationship between EHI with other endpoints. We assessed the relationship between EHI and the simplified Magnetic Resonance Index of Activity. MATERIALS AND METHODS: Data were prospectively collected on patients with CD with either an EHI or fecal calprotectin (FCAL) within 90 days of magnetic resonance enterography (MRE). Diagnostic accuracy was assessed using area under the receiver operator characteristics. Proportions with any, severe, and terminal ileum MR inflammation were compared above/below identified thresholds for both EHI and FCAL. RESULTS: A total of 241 MREs paired to either EHI or FCAL from 155 patients were included. Both EHI and FCAL had similar accuracy to diagnose inflammation (area under the receiver operator characteristics: EHI: 0.635 to 0.651, FCAL: 0.680 to 0.708). Optimal EHI values were 42 and 26 for inflammation on MRE and endoscopy, respectively. Patients with EHI ≥42 (100% vs. 63%, P=0.002), FCAL >50 µg/g (87% vs. 64%, P<0.001) and FCAL >250 µg/g (90% vs. 75%, P=0.02) had higher rates of simplified Magnetic Resonance Index of Activity ≥1 compared with lower values. EHI differentiated ileitis numerically more than FCAL (delta: 24% to 25% vs. 11% to 21%). Patients with FCAL ≥50 µg/g had higher rates of severe inflammation compared with FCAL <50 µg/g (75% vs. 47%, P<0.001), whereas smaller differentiation existed for EHI threshold of 42 (63% vs. 49%, P=0.35). CONCLUSION: Both EHI and FCAL were specific in their confirmation of inflammation and disease activity on MRE in patients with CD. However, MRE-detected inflammation was frequently present in the presence of low EHI and FCAL in similar proportions.

The Impact of Confounders on Symptom-Endoscopic Discordances in Crohn's Disease.

Background: Discordances between clinical and endoscopic Crohn's disease (CD) activity indices negatively impact the utility of clinic visits and efficacy assessments in clinical trials. Bile acid diarrhea (BAD) and small intestinal bacterial overgrowth (SIBO) mimic CD symptoms. This study quantified the impact of BAD and SIBO on the relationship between clinical and endoscopic disease activity indices. Methods: CD patients with 7α-hydroxy-4-cholesten-3-one (7C4) serum measurements and/or SIBO breath tests and matched clinical and endoscopic scores were included. Clinical remission (stool frequency [SF] ≤ 1 and abdominal pain score ≤ 1) rates were compared between those with and without (1) endoscopic remission, (2) BAD (7C4 > 55 ng/mL), and (3) SIBO. Results: Of 295 CD patients, 219 had SIBO testing and 87 had 7C4 testing. Patients with elevated 7C4 had lower proportions with clinical remission (14% vs 40%, P = .007) and SF ≤ 1 (14% vs 42%, P = .004) compared to those with normal 7C4. In patients with normal 7C4, higher rates of clinical remission (65% vs 27%, P = .01) and SF ≤ 1 (71% vs 27%, P = .003) existed in patients with endoscopic remission compared to those without endoscopic remission. Conversely, among the entire 295 patient cohorts, nearly identical clinical remission rates existed between those with and without endoscopic remission (25% vs 24%, P = .8), and the Crohn's Disease Patient-Reported Outcome-2 score was not accurate for predicting endoscopic remission (Area Under the Curve (AUC): 0.48; 95% CI, 0.42-0.55). SIBO status did not impact clinical remission rates (P = 1.0). Conclusions: BAD, but not SIBO, contributed to symptom scores. A relationship between endoscopic inflammation and clinical remission rates only existed in patients without 7C4 elevations.

Increased Primary Bile Acids with Ileocolonic Resection Impact Ileal Inflammation and Gut Microbiota in Inflammatory Bowel Disease.

BACKGROUND: Most Crohn's disease [CD] patients require surgery. Ileitis recurs after most ileocolectomies and is a critical determinant for outcomes. The impacts of ileocolectomy-induced bile acid [BA] perturbations on intestinal microbiota and inflammation are unknown. We characterized the relationships between ileocolectomy, stool BAs, microbiota and intestinal inflammation in inflammatory bowel disease [IBD]. METHODS: Validated IBD clinical and endoscopic assessments were prospectively collected. Stool primary and secondary BA concentrations were compared based on ileocolectomy and ileitis status. Primary BA thresholds for ileitis were evaluated. Metagenomic sequencing was use to profile microbial composition and function. Relationships between ileocolectomy, BAs and microbiota were assessed. RESULTS: In 166 patients, elevated primary and secondary BAs existed with ileocolectomy. With ileitis, only primary BAs [795 vs 398 nmol/g, p = 0.009] were higher compared to without ileitis. The optimal primary BA threshold [≥228 nmol/g] identified ileitis on multivariable analysis [odds ratio = 2.3, p = 0.04]. Microbial diversity, Faecalibacterium prausnitzii and O-acetylhomoserine aminocarboxypropyltransferase [MetY] were decreased with elevated primary BAs. Amongst ileocolectomy patients, only those with elevated primary BAs had diversity, F. prausnitzii and MetY reductions. Those with both ileocolectomy and intermediate [p = 0.002] or high [≥228 nmol/g, p = 9.1e-11]] primary BA concentrations had reduced F. prausnitzii compared to without ileocolectomy. Those with ileocolectomy and low [<29.2 nmol/g] primary BA concentrations had similar F. prausnitzii to those without ileocolectomy [p = 0.13]. MetY was reduced with ileitis [p = 0.02]. CONCLUSIONS: Elevated primary BAs were associated with ileitis, and reduced microbial diversity, F. prausnitzii abundance and enzymatic abundance of MetY [acetate and l-methionine-producing enzyme expressed by F. prausnitzii], and were the only factors associated with these findings after ileocolectomy.

Utility of Therapeutic Drug Monitoring for Tumor Necrosis Factor Antagonists and Ustekinumab in Postoperative Crohn's Disease.

BACKGROUND: In postoperative Crohn's disease (POCD), data are lacking on relationships between serum biologic concentrations and treatment outcomes. We assessed if established threshold concentrations of infliximab (IFX), adalimumab (ADA), and ustekinumab (UST) impact outcomes in POCD. METHODS: Data were extracted from POCD patients with serum biologic concentration measurements using Weill Cornell Medicine biobanks. The primary outcome compared rates of deep remission (achieving both objective [endoscopic or biomarker] and clinical [Harvey-Bradshaw index or Crohn's Disease Patient Reported Outcome-2] remission), using established serum drug level cutoffs of IFX ≥3 µg/mL, ADA ≥7.5 µg/mL, and UST ≥4.5 µg/mL. RESULTS: In 130 patients, median IFX, ADA, and UST concentrations were 10 (interquartile range [IQR], 2.9-26.9) µg/mL, 10.5 (IQR, 4.9-14.9) µg/mL, and 6.9 (IQR, 5.1-10.2) µg/mL, respectively. In patients with IFX ≥3 µg/mL, higher rates of deep remission (39% vs 0%; P = .02) existed compared with those with IFX <3 µg/mL. Similar differences existed for clinical (44% vs 9%; P = .04) and objective (83% vs 62%; P = .1) remission. In patients with ADA ≥7.5 µg/mL, rates of deep (42% vs 0%; P = .02), clinical (42% vs 0%; P = .02), and objective (88% vs 40%; P = .007) remission were higher than patients with lower concentrations. For UST, rates of deep (28% vs 17%; P = 1.0), clinical (33% vs 33%; P = 1.0), and objective (70% vs 67%; P = 1.0) remission were similar between patients regardless of drug concentration. CONCLUSIONS: In POCD, established anti-tumor necrosis factor concentrations were associated with improved outcomes. No relationship between UST concentrations and postoperative outcomes existed.

Data are lacking on therapeutic drug monitoring in postoperative Crohn's disease. The current study found that tumor necrosis factor antagonist concentrations above established drug thresholds were associated with improved outcomes. In contrast, for ustekinumab, no relationship between drug thresholds and outcomes existed.

Cross-Subtype Detection of HIV-1 Capsid p24 Antigen Using a Sensitive Europium Nanoparticle Assay.

Accurate and early detection of diverse HIV-1 subtypes using currently available p24 antigen assays have been a major challenge. We report the development of a sensitive time resolved fluorescence (TRF) europium nanoparticle immuno assay for cross subtype detection of p24 antigen using broadly cross-reactive antibodies. Several antibodies were tested for optimal reactivity with antigens of diverse HIV-1 subtypes and circulating recombinant forms. We tested HIV strains using this assay for sensitivity and quantification ability at the pico-gram per millilter level. We identified two broadly cross-reactive HIV-1 p24 antibodies C65690M and ANT-152, which detected all strains of HIV tested. These two antibodies also yielded a better signal to cutoff ratio for the same amount of antigen tested in comparison to a commercial assay. Using an appropriate combination of C65690M and ANT-152 p24 antibodies capable of detecting all HIV types and highly sensitive TRF-based europium nano particle assay platform, we developed a sensitive p24 antigen assay that can detect HIV infection of all HIV subtypes and may be useful in early detection.

Novel Time-Resolved Fluorescence Europium Nanoparticle Immunoassay for Detection of Human Immunodeficiency Virus-1 Group O Viruses Using Microplate and Microchip Platforms.

Accurate detection and quantification of HIV-1 group O viruses have been challenging for currently available HIV assays. We have developed a novel time-resolved fluorescence (TRF) europium nanoparticle immunoassay for HIV-1 group O detection using a conventional microplate enzyme-linked immunosorbent assay (ELISA) and a microchip platform. We screened several antibodies for optimal reactivity with several HIV-1 group O strains and identified antibodies that can detect all the strains of HIV-1 group O that were available for testing. The antibodies were used to develop a conventional ELISA format assay and an in-house developed europium nanoparticle-based assay for sensitivity. The method was evaluated on both microwell plate and microchip platforms. We identified two specific and sensitive antibodies among the six we screened. The antibodies, C65691 and ANT-152, were able to quantify 15 and detect all 17 group O viruses, respectively, as they were broadly cross-reactive with all HIV-1 group O strains and yielded better signals compared with other antibodies. We have developed a sensitive assay that reflects the actual viral load in group O samples by using an appropriate combination of p24 antibodies that enhance group O detection and a highly sensitive TRF-based europium nanoparticle for detection. The combination of ANT-152 and C65690M in the ratio 3:1 was able to give significantly higher signals in our europium-based assay compared with using any single antibody.