Single-cell, single-nucleus, and spatial transcriptomics characterization of the immunological landscape in the healthy and PSC human liver

BACKGROUND & AIMS

Primary sclerosing cholangitis (PSC) is an immune-mediated cholestatic liver disease for which there is an unmet need to understand the cellular composition of the affected liver and how it underlies disease pathogenesis. We aimed to generate a comprehensive atlas of the PSC liver using multi-omic modalities and protein-based functional validation.

METHODS

We employed single-cell and single-nucleus RNA sequencing (47,156 cells and 23,000 nuclei) and spatial transcriptomics (one sample by 10x Visium and five samples with Nanostring GeoMx DSP) to profile the cellular ecosystem in 10 PSC livers. Transcriptomic profiles were compared to 24 neurologically deceased donor livers (107,542 cells) and spatial transcriptomics controls, as well as 18,240 cells and 20,202 nuclei from three PBC livers. Flow cytometry was performed to validate PSC-specific differences in immune cell phenotype and function.

RESULTS

PSC explants with parenchymal cirrhosis and prominent periductal fibrosis contained a population of cholangiocyte-like hepatocytes that were surrounded by diverse immune cell populations. PSC-associated biliary, mesenchymal, and endothelial populations expressed chemokine and cytokine transcripts involved in immune cell recruitment. Additionally, expanded CD4+ T cells and recruited myeloid populations in the PSC liver expressed the corresponding receptors to these chemokines and cytokines, suggesting potential recruitment. Tissue-resident macrophages, by contrast, were reduced in number and exhibited a dysfunctional and downregulated inflammatory response to lipopolysaccharide and interferon-γ stimulation.

CONCLUSIONS

We present a comprehensive atlas of the PSC liver and demonstrate an exhaustion-like phenotype of myeloid cells and markers of chronic cytokine expression in late-stage PSC lesions. This atlas expands our understanding of the cellular complexity of PSC and has potential to guide the development of novel treatments.

IMPACT AND IMPLICATIONS

Primary sclerosing cholangitis (PSC) is a rare liver disease characterized by chronic inflammation and irreparable damage to the bile ducts, which eventually results in liver failure. Due to a limited understanding of the underlying pathogenesis of disease, treatment options are limited. To address this, we sequenced healthy and diseased livers to compare the activity, interactions, and localization of immune and non-immune cells. This revealed that hepatocytes lining PSC scar regions co-express cholangiocyte markers, whereas immune cells infiltrate the scar lesions. Of these cells, macrophages, which typically contribute to tissue repair, were enriched in immunoregulatory genes and demonstrated a lack of responsiveness to stimulation. These cells may be involved in maintaining hepatic inflammation and could be a target for novel therapies.

Pursuing living donor liver transplantation improves outcomes of patients with autoimmune liver diseases - An intention-to-treat analysis

Background Living donor liver transplantation (LDLT) offers the opportunity to decrease waitlist time and mortality for patients with AILD; autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC). We compared the survival of patients with a potential live donor (pLDLT) on the waitlist vs. no potential live donor (pDDLT), on an intention-to-treat (ITT) basis. Methods Our retrospective cohort study investigated adults with AILD listed for liver transplant at our program between 2000 and 2021. The pLDLT group comprised recipients with a potential live donor. Otherwise, they were included in the pDDLT group. ITT survival was assessed from the time of listing. Results Of the 533 patients included, 244(43.8%) had a potential living donor. Waitlist dropout was higher for the pDDLT groups among all AILDs (pDDLT 85[29.4%] vs. pLDLT 9[3.7], p<0.001). The 1-, 3- and 5-year ITT survival rates were higher for pLDLT vs. pDDLT among all AILDs (95.7%vs.78.1%, 89.0%vs.70.1%, and 87.1%vs.65.5%, p<0.001). After adjusting for covariates, pLDLT was associated with a 38% reduction in the risk of death among the AILD cohort (HR:0.62, 95%CI:0.42-0.93[p<0.05]), and 60% among the PSC cohort (HR:0.40, 95%CI:0.22-0.74[p<0.05]). There were no differences in the 1-, 3- and 5-year post-transplant survival between LDLT and DDLT (AILD: 95.6%vs.92.1%, 89.9%vs.89.4%, and 89.1%vs. 87.1%, p=0.41). This was consistent after adjusting for covariates (HR: 0.97, 95%CI:0.56-1.68[p>0.9]). Conclusion Our study suggests that having a potential live donor could decrease the risk of death in patients with PSC on the waitlist. Importantly, the post-transplant outcomes in this population are similar between the LDLT and DDLT groups.

Adequate versus deep response to ursodeoxycholic acid in primary biliary cholangitis: To what extent and under what conditions is normal alkaline phosphatase level associated with complication-free survival gain?

BACKGROUND AND AIMS

Normal alkaline phosphatase (ALP) levels in ursodeoxycholic acid (UDCA)-treated patients with primary biliary cholangitis (PBC) are associated with better long-term outcome. However, second-line therapies are currently recommended only when ALP levels remain above 1.5 times the upper limit of normal (×ULN) after 12-month UDCA. We assessed whether, in patients considered good responders to UDCA, normal ALP levels were associated with significant survival gains.

APPROACH AND RESULTS

We performed a retrospective cohort study of 1047 patients with PBC who attained an adequate response to UDCA according to Paris-2 criteria. Time to liver-related complications, liver transplantation, or death was assessed using adjusted restricted mean survival time (RMST) analysis. The overall incidence rate of events was 17.0 (95% CI: 13.7-21.1) per 1000 out of 4763.2 patient-years. On the whole population, normal serum ALP values (but not normal gamma-glutamyl transpeptidase (GGT), alanine aminotransferase (ALT), or aspartate aminotransferase (AST); or total bilirubin < 0.6 ×ULN) were associated with a significant absolute complication-free survival gain at 10 years (mean 7.6 months, 95% CI: 2.7 - 12.6 mo.; p = 0.003). In subgroup analysis, this association was significant in patients with a liver stiffness measurement ≥ 10 kPa and/or age ≤ 62 years, with a 10-year absolute complication-free survival gain of 52.8 months (95% CI: 45.7-59.9, p < 0.001) when these 2 conditions were met.

CONCLUSIONS

PBC patients with an adequate response to UDCA and persistent ALP elevation between 1.1 and 1.5 ×ULN, particularly those with advanced fibrosis and/or who are sufficiently young, remain at risk of poor outcome. Further therapeutic efforts should be considered for these patients.

Seladelpar efficacy and safety at 3 months in patients with primary biliary cholangitis: ENHANCE, a phase 3, randomized, placebo-controlled study

BACKGROUND AND AIMS

ENHANCE was a phase 3 study that evaluated efficacy and safety of seladelpar, a selective peroxisome proliferator-activated receptor-δ (PPAR) agonist, versus placebo in patients with primary biliary cholangitis with inadequate response or intolerance to ursodeoxycholic acid (UDCA).

APPROACH AND RESULTS

Patients were randomized 1:1:1 to oral seladelpar 5 mg (n=89), 10 mg (n=89), placebo (n=87) daily (with UDCA, as appropriate). Primary end point was a composite biochemical response [alkaline phosphatase (ALP) < 1.67×upper limit of normal (ULN), ≥15% ALP decrease from baseline, and total bilirubin ≤ ULN] at month 12. Key secondary end points were ALP normalization at month 12 and change in pruritus numerical rating scale (NRS) at month 6 in patients with baseline score ≥4. Aminotransferases were assessed. ENHANCE was terminated early following an erroneous safety signal in a concurrent, NASH trial. While blinded, primary and secondary efficacy end points were amended to month 3. Significantly more patients receiving seladelpar met the primary end point (seladelpar 5 mg: 57.1%, 10 mg: 78.2%) versus placebo (12.5%) ( p < 0.0001). ALP normalization occurred in 5.4% ( p =0.08) and 27.3% ( p < 0.0001) of patients receiving 5 and 10 mg seladelpar, respectively, versus 0% receiving placebo. Seladelpar 10 mg significantly reduced mean pruritus NRS versus placebo [10 mg: -3.14 ( p =0.02); placebo: -1.55]. Alanine aminotransferase decreased significantly with seladelpar versus placebo [5 mg: 23.4% ( p =0.0008); 10 mg: 16.7% ( p =0.03); placebo: 4%]. There were no serious treatment-related adverse events.

CONCLUSIONS

Patients with primary biliary cholangitis (PBC) with inadequate response or intolerance to UDCA who were treated with seladelpar 10 mg had significant improvements in liver biochemistry and pruritus. Seladelpar appeared safe and well tolerated.

Living donor liver transplantation can address disparities in transplant access for patients with primary sclerosing cholangitis

BACKGROUND

Liver transplantation (LT) is frequently lifesaving for people living with primary sclerosing cholangitis (PSC). However, patients are waitlisted for LT according to the model for end-stage liver disease-sodium (MELD-Na) score, which may not accurately reflect the burden of living with PSC. We sought to describe and analyze the clinical trajectory for patients with PSC referred for LT, in a mixed deceased donor/living donor transplant program.

METHODS

This was a retrospective cohort study from November 2012 to December 2019, including all patients with PSC referred for assessment at the University Health Network Liver Transplant Clinic. Patients who required multiorgan transplant or retransplantation were excluded. Liver symptoms, hepatobiliary malignancy, MELD-Na progression, and death were abstracted from chart review. Competing risk analysis was used for timing of LT, transplant type, and death.

RESULTS

Of 172 PSC patients assessed, 84% (n = 144) were listed of whom 74% were transplanted. Mean age was 47.6 years, and 66% were male. Overall mortality was 18.2% at 2 years. During the follow-up, 16% (n = 23) were removed from the waitlist for infection, clinical deterioration, liver-related mortality or new cancer; 3 had clinical improvement. At listing, 82% (n = 118) had a potential living donor (pLD). Patients with pLD had significantly lower waitlist and liver-related waitlist mortality (HR 0.20, p<0.001 and HR 0.17, p<0.001, respectively), and higher rates of transplantation (HR 1.83, p = 0.05). Exception points were granted to 13/172 (7.5%) patients.

CONCLUSIONS

In a high-volume North American LT center, most patients with PSC assessed for transplant were listed and subsequently transplanted. However, this was a consequence of patients engaging in living donor transplantation. Our findings support the concern from patients with PSC that MELD-Na allocation does not adequately address their needs.

Optimizing therapy in primary biliary cholangitis: Alkaline phosphatase at six months identifies one-year non-responders and predicts survival

BACKGROUND AND AIMS

Patients with primary biliary cholangitis (PBC) and insufficient response to ursodeoxycholic acid (UDCA), currently assessed after 1 year, are candidates for second-line therapy. The aims of this study are to assess biochemical response pattern and determine the utility of alkaline phosphatase (ALP) at six months as a predictor of insufficient response.

METHODS

UDCA-treated patients in the GLOBAL PBC database with available liver biochemistries at one year were included. POISE criteria were used to assess response to treatment, defined as ALP <1.67 × upper limit of normal (ULN) and normal total bilirubin at one year. Various thresholds of ALP at six months were evaluated to predict insufficient response based on negative predictive value (NPV) and that with nearest to 90% NPV was selected.

RESULTS

For the study, 1362 patients were included, 1232 (90.5%) female, mean age of 54 years. The POISE criteria were met by 56.4% (n = 768) of patients at one year. The median ALP (IQR) of those who met POISE criteria compared to those who did not was 1.05 × ULN (0.82-1.33) vs. 2.37 × ULN (1.72-3.69) at six months (p < .001). Of 235 patients with serum ALP >1.9 × ULN at six months, 89% did not achieve POISE criteria (NPV) after one year of UDCA. Of those with insufficient response by POISE criteria at one year, 210 (67%) had an ALP >1.9 × ULN at six months and thus would have been identified early.

CONCLUSIONS

We can identify patients for second-line therapy at six months using an ALP threshold of 1.9 × ULN, given that approximately 90% of these patients are non-responders according to POISE criteria.

A44 A 1000 PATIENT CANADIAN NETWORK FOR AUTOIMMUNE LIVER DISEASE EVALUATION OF CLINICAL AND DEMOGRAPHIC PATTERNS OF AUTOIMMUNE HEPATITIS

Background

We sought to understand how the demographics of autoimmune hepatitis (AIH) have changed over time in Canada.

Purpose

Using a large multi-centre Canadian cohort of patients with AIH, we describe the trends in patient and disease characteristics at presentation across 30 years of clinical practice.

Method

Patients from the Canadian Network for Autoimmune Liver Disease with a confirmed diagnosis of AIH (simplified score ≥6) were included for analysis. Patients were grouped into five cohorts according to the year of diagnosis (i.e., <2000, 2000-2004, 2005-2009, 2010-2014, ≥2015). Patient demographics and baseline clinical and biochemistry features of disease activity were investigated using Chi-square tests and Kruskal-Wallis tests adjusted for multiple comparisons. Logistic and linear regression models with estimated means were utilized to further investigate relationships with time and to adjust for confounding.

Result(s)

1016 patients followed across 10 Canadian health centres with AIH were diagnosed between November 1965 and December 2021. Overall, 76.4% (n=776) of patients were female, and the median age at diagnosis was 46 years (IQR 28.2 - 58.3). Cirrhosis at presentation was seen in 20.6% of patients (n=209). The median age at diagnosis increased significantly from 31.8 years [IQR 17.9 - 46.8] pre-2000 to 54 years [IQR 9.0 - 95.2] after 2014 (p<0.001; Figure 1a). This effect of time persisted after adjusting for sex and cirrhosis status at diagnosis. Female sex and the presence of cirrhosis at diagnosis were factors independently associated with older age at presentation (p<0.0001).

The proportion of patients that presented with cirrhosis at diagnosis increased significantly over calendar time, from 13.7% (n=23) pre-2000 to 30.8% (n=69) after 2014 (p=0.003; Figure 1b). Male sex was independently associated with an increased odds of having cirrhosis at presentation (OR= 1.46, CI 1.02 - 2.07) and higher baseline ALT levels compared to females (p=0.036). The proportion of patients that identified as non-white ethnicity increased significantly from 15.2% (n= 24) pre-2000, to 32% (n= 86) after 2014 (p<0.001, Figure 1b). This effect of time on ethnicity was most pronounced after the year 2010 (OR= 2.32, CI 1.39 - 3.98) and persisted after adjusting for sex. There was no significant pattern of change in sex over calendar time.

Image

Conclusion(s)

In Canada, patients with AIH at presentation are now older, have more advanced disease, and are more ethnically diverse than when compared to 30 years ago.

Please acknowledge all funding agencies by checking the applicable boxes below

Other

Please indicate your source of funding;

industry

Disclosure of Interest

None Declared

A42 LIVE DONOR LIVER TRANSPLANTATION IN PRIMARY SCLEROSING CHOLANGITIS: AN INDICATOR OF AN ORGAN ALLOCATION SYSTEM NOT ADDRESSING PATIENT NEED

Background

Liver transplantation is frequently lifesaving for people living with primary sclerosing cholangitis (PSC). However, patients are waitlisted for liver transplant (LT) according to the MELD-Na score, which may not accurately reflect the burden of living with PSC.

Purpose

We sought to describe and analyze the clinical trajectory for patients with PSC referred for LT, in a mixed deceased donor/live donor transplant programme.

Method

This was a retrospective cohort study from November 2012 to December 2019 including all patients with PSC referred for assessment at the University Health Network Liver Transplant Clinic. Patients who required multiorgan transplant or re-transplantation were excluded. Liver symptoms, hepatobiliary malignancy, MELD-Na progression, and death were abstracted from chart review. Competing Risk analysis was used for timing of LT, transplant type, and death.

Result(s)

Of 172 PSC patients assessed, 144 (84%) were listed, of whom 106/144 (74%) were transplanted. Mean age was 47.6 years and 66% were male. During follow-up through to 2021, 23/144 (16%) were removed from the waitlist due to infection, clinical deterioration, liver-related mortality or new cancer; 3 had clinical improvement. At the time of listing, 118/144 (81.95%) had a potential Living Donor (pLD) of whom 94 were transplanted: 64 live donor and 30 deceased donor. Patients with pLD had 79% lower mortality (p<0.001), and higher rates of transplantation (80% vs 46%). Exception points were granted to 13/172 (7.5%) patients.

Conclusion(s)

In a high-volume North American liver transplant centre, most patients with PSC assessed for transplant were listed and subsequently transplanted. However, this was a consequence of patients engaging in live donor transplantation. Our findings support the concern from patients with PSC that MELD-Na allocation does not adequately address their needs.

Please acknowledge all funding agencies by checking the applicable boxes below

CIHR, Other

Please indicate your source of funding;

This study was supported by PSC Partners Canada, Canadian Institutes of Health Research (CIHR), Toronto General and Western Hospital Foundation.

Disclosure of Interest

None Declared

IL-31 levels correlate with pruritus in patients with cholestatic and metabolic liver diseases and is farnesoid X receptor responsive in NASH

BACKGROUND AND AIMS

Pruritus is associated with multiple liver diseases, particularly those with cholestasis, but the mechanism remains incompletely understood. Our aim was to evaluate serum IL-31 as a putative biomarker of pruritus in clinical trials of an farnesoid X receptor (FXR) agonist, cilofexor, in patients with NASH, primary sclerosing cholangitis (PSC), and primary biliary cholangitis (PBC).

APPROACH AND RESULTS

Serum IL-31 was measured in clinical studies of cilofexor in NASH, PSC, and PBC. In patients with PSC or PBC, baseline IL-31 was elevated compared to patients with NASH and healthy volunteers (HVs). IL-31 correlated with serum bile acids among patients with NASH, PBC, and PSC. Baseline IL-31 levels in PSC and PBC were positively correlated with Visual Analog Scale for pruritus and 5-D itch scores. In patients with NASH, cilofexor dose-dependently increased IL-31 from Week (W)1 to W24. In patients with NASH receiving cilofexor 100 mg, IL-31 was higher in those with Grade 2-3 pruritus adverse events (AEs) than those with Grade 0-1 pruritus AEs. IL-31 weakly correlated with C4 at baseline in patients with NASH, and among those receiving cilofexor 100 mg, changes in IL-31 and C4 from baseline to W24 were negatively correlated. IL-31 messenger RNA (mRNA) was elevated in hepatocytes from patients with PSC and NASH compared to HVs. In a humanized liver murine model, obeticholic acid increased IL-31 mRNA expression in human hepatocytes and serum levels of human IL-31.

CONCLUSIONS

IL-31 levels correlate with pruritus in patients with cholestatic disease and NASH, with FXR agonist therapy resulting in higher serum levels in the latter group. IL-31 appears to derive in part from increased hepatocyte expression. These findings have therapeutic implications for patients with liver disease and pruritus.

Liver stiffness measurement by vibration-controlled transient elastography improves outcome prediction in primary biliary cholangitis

BACKGROUND & AIMS

Liver stiffness measurement (LSM) by vibration-controlled transient elastography (VCTE) has been shown to predict outcomes of patients with primary biliary cholangitis (PBC) in small-size studies. We aimed to validate the prognostic value of LSM in a large cohort study.

METHODS

We performed an international, multicentre, retrospective follow-up study of 3,985 patients with PBC seen at 23 centres in 12 countries. Eligibility criteria included at least 1 reliable LSM by VCTE and a follow-up ≥ 1 year. Independent derivation (n = 2,740) and validation (n = 568) cohorts were built. The primary endpoint was time to poor clinical outcomes defined as liver-related complications, liver transplantation, or death. Hazard ratios (HRs) with CIs were determined using a time-dependent multivariable Cox regression analysis.

RESULTS

LSM was independently associated with poor clinical outcomes in the derivation (5,324 LSMs, mean follow-up 5.0 ± 3.1 years) and validation (1,470 LSMs, mean follow-up 5.0 ± 2.8 years) cohorts: adjusted HRs (95% CI) per additional kPa were 1.040 (1.026-1.054) and 1.042 (1.029-1.056), respectively (p <0.0001 for both). Adjusted C-statistics (95% CI) at baseline were 0.83 (0.79-0.87) and 0.92 (0.89-0.95), respectively. Between 5 and 30 kPa, the log-HR increased as a monotonic function of LSM. The predictive value of LSM was stable in time. LSM improved the prognostic ability of biochemical response criteria, fibrosis scores, and prognostic scores. The 8 kPa and 15 kPa cut-offs optimally separated low-, medium-, and high-risk groups. Forty percent of patients were at medium to high risk according to LSM.

CONCLUSIONS

LSM by VCTE is a major, independent, validated predictor of PBC outcome. Its value as a surrogate endpoint for clinical benefit in PBC should be considered.

LAY SUMMARY

Primary biliary cholangitis (PBC) is a chronic autoimmune disease, wherein the body's immune system mistakenly attacks the bile ducts. PBC progresses gradually, so surrogate markers (markers that predict clinically relevant outcomes like the need for a transplant or death long before the event occurs) are often needed to expedite the drug development and approval process. Herein, we show that liver stiffness measurement is a strong predictor of clinical outcomes and could be a useful surrogate endpoint in PBC trials.

Greater Transplant-Free Survival in Patients Receiving Obeticholic Acid for Primary Biliary Cholangitis in a Clinical Trial Setting Compared to Real-World External Controls

BACKGROUND & AIMS

The Primary Biliary Cholangitis (PBC) Obeticholic Acid (OCA) International Study of Efficacy (POISE) randomized, double-blind, placebo-controlled trial demonstrated that OCA reduced biomarkers associated with adverse clinical outcomes (ie, alkaline phosphatase, bilirubin, aspartate aminotransferase, and alanine aminotransferase) in patients with PBC. The objective of this study was to evaluate time to first occurrence of liver transplantation or death in patients with OCA in the POISE trial and open-label extension vs comparable non-OCA-treated external controls.

METHODS

Propensity scores were generated for external control patients meeting POISE eligibility criteria from 2 registry studies (Global PBC and UK-PBC) using an index date selected randomly between the first and last date (inclusive) on which eligibility criteria were met. Cox proportional hazards models weighted by inverse probability of treatment assessed time to death or liver transplantation. Additional analyses (Global PBC only) added hepatic decompensation to the composite end point and assessed efficacy in patients with or without cirrhosis.

RESULTS

During the 6-year follow-up, there were 5 deaths or liver transplantations in 209 subjects in the POISE cohort (2.4%), 135 of 1381 patients in the Global PBC control (10.0%), and 281 of 2135 patients in the UK-PBC control (13.2%). The hazard ratios (HRs) for the primary outcome were 0.29 (95% CI, 0.10-0.83) for POISE vs Global PBC and 0.30 (95% CI, 0.12-0.75) for POISE vs UK-PBC. In the Global PBC study, HR was 0.20 (95% CI, 0.03-1.22) for patients with cirrhosis and 0.31 (95% CI, 0.09-1.04) for those without cirrhosis; HR was 0.42 (95% CI, 0.21-0.85) including hepatic decompensation.

CONCLUSIONS

Patients treated with OCA in a trial setting had significantly greater transplant-free survival than comparable external control patients.

Inflammatory conditions play a role in recurrence of PSC after liver transplantation – an international multicentre study

Background & Aims

Liver transplantation (LT) for primary sclerosing cholangitis (PSC) is complicated by recurrence of PSC (rPSC) in up to 25% of recipients. Recurrence has been shown to be detrimental for both graft and patient survival. For both PSC and rPSC, a medical cure is not available. To predict and ideally to prevent rPSC, it is imperative to find risk factors for rPSC that can be potentially modified. Therefore, we aimed to identify such factors for rPSC in a large international multicentre study including 6 centres in PSC-prevalent countries.

Methods

In this international multicentre, retrospective cohort study, 531 patients who underwent transplantation for PSC were included. In 25% of cases (n = 131), rPSC was diagnosed after a median follow-up of 6.72 (3.29–10.11) years post-LT.

Results

In the multivariable competing risk model with time-dependent covariates, we found that factors representing an increased inflammatory state increase the risk for rPSC. Recurrent cholangitis before LT as indication for LT (hazard ratio [HR] 3.6, 95% CI 2.5–5.2), increased activity of inflammatory bowel disease after LT (HR 1.7, 95% CI 1.08–2.75), and multiple acute cellular rejections (HR: non-linear) were significantly and independently associated with an increased risk of rPSC. In contrast to the findings of previous studies, pretransplant colectomy was not found to be independently protective against the development of rPSC.

Conclusions

An increased inflammatory state before and after LT may play a causal and modifiable role in the development of rPSC. Pretransplant colectomy did not reduce the risk of rPSC per se. Recurrent cholangitis as indication for LT was associated with an increased risk of rPSC.

Impact and implications

Recurrence of PSC (rPSC) negatively affects survival after liver transplant (LT). Modifiable risk factors could guide clinical management and prevention of rPSC. We demonstrate that an increased inflammatory state both before and after LT increases the incidence of rPSC. As these are modifiable factors, they could serve as targets for future studies and therapies. We also added further evidence to the ongoing debate regarding preventive colectomy for rPSC by reporting that in our multicenter study, we could not find an independent association between colectomy and risk of rPSC.

•

rPSC occurred after LT in 25% of recipients in this multicentre study from 6 transplant centres (Europe and North America).

•

An increased systemically inflammatory state, both before and after LT, increases the risk of rPSC development.

•

Increased IBD activity post-LT was associated with a higher risk of rPSC development.

•

Performing a colectomy before LT was not associated with a reduction of rPSC.

Safety and sustained efficacy of the farnesoid X receptor (FXR) agonist cilofexor over a 96-week open-label extension in patients with PSC

BACKGROUND & AIMS

Primary sclerosing cholangitis (PSC) is a major unmet medical need in clinical hepatology. Cilofexor is a nonsteroidal farnesoid X receptor agonist being evaluated for the treatment of PSC. Here, we describe the safety and preliminary efficacy of cilofexor in a 96-week, open-label extension (OLE) of a phase II trial.

METHODS

Noncirrhotic subjects with large-duct PSC who completed the 12-week, blinded phase of a phase II study (NCT02943460) were eligible, after a 4-week washout period, for a 96-week OLE with cilofexor 100 mg daily. Safety, liver biochemistry, and serum markers of fibrosis, cellular injury, and pharmacodynamic effects of cilofexor (fibroblast growth factor 19, C4, and bile acids [BAs]) were evaluated.

RESULTS

Among 52 subjects enrolled in the phase II study, 47 (90%) continued in the OLE phase (median age, 44 years; 60% male patients, 60% with inflammatory bowel disease, and 45% on ursodeoxycholic acid [UDCA]). At OLE baseline (BL), the median serum alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) were 368 U/L (interquartile range [IQR], 277-468 U/L) and 417 U/L (IQR, 196-801 U/L), respectively. Of the 47 subjects enrolled, 15 (32%) discontinued treatment prematurely (pruritus [n = 5], other adverse events [n = 5], subject decision/investigator discretion [n = 5]). At week 96, reductions in liver biochemistry parameters occurred, including serum ALP (median, -8.3% [IQR, -25.9% to 11.0%]; P = .066), GGT (-29.8% [IQR, -42.3% to -13.9%]; P < .001), alanine aminotransaminase (ALT) (-29.8% [IQR, -43.7% to -6.6%]; P = .002), and aspartate aminotransaminase (AST) (-16.7% [IQR, -35.3% to 1.0%]; P = .010), and rebounded after 4 weeks of untreated follow-up. ALP response (≥20% reduction from BL to week 96) was similar in the presence or absence of UDCA therapy (29% vs 39%; P = .71). At week 96, cilofexor treatment was associated with a significant reduction in serum 7α-hydroxy-4-cholesten-3-one (C4) (-29.8% [IQR, -64.3% to -8.5%]; P = .001). In subjects with detectable serum BAs at BL (n = 40), BAs decreased -23.9% (IQR, -44.4% to -0.6%; P = .006) at week 48 (n = 28) and -25.7% (IQR, -35.9% to 53.7%; P = .91) at week 96 (n = 26). Serum cytokeratin 18 (CK18) M30 and M65 were reduced throughout the OLE; significant reductions were observed at week 72 (CK18 M30, -17.3% [IQR, -39.3% to 8.8%]; P = .018; CK18 M65, -43.5% [IQR, -54.9% to 15.3%]; P = .096). At week 96, a small, but statistically significant absolute increase of 0.15 units in Enhanced Liver Fibrosis score was observed compared with BL (median, 9.34 vs 9.53; P = .028).

CONCLUSIONS

In this 96-week OLE of a phase II study of PSC, cilofexor was safe and improved liver biochemistry and biomarkers of cholestasis and cellular injury.

CLINICALTRIALS

gov identifier: NCT02943460.

A210 HEPATOLITHIASIS IS A FREQUENT AND PROGNOSTIC FINDING IN PATIENTS WITH PRIMARY SCLEROSING CHOLANGITIS

Aims

Intrahepatic biliary stones (hepatolithiasis) are not well characterised in patients with primary sclerosing cholangitis (PSC).

Methods

Chart reviews were conducted on 302 patients with a histologic or radiographic diagnosis of PSC followed at the Toronto Centre for Liver Disease. Radiographic data were collected for patients between the years 2008–2018. Depending on frequency of testing, magnetic resonance imaging (MRI) and ultrasound (US) data was reviewed every 3–5 years. We assessed factors associated with hepatolithiasis based on sex, race, age and phenotype of PSC and inflammatory bowel disease (IBD). Qualitative radiographic findings on image report review, episodes of cholangitis, endoscopic retrograde cholangiopancreatography (ERCP) and occurrence of cholangiocarcinoma (CCA), death and transplant were documented. Data are reported with median and IQR and analysed using χ ² and Mann-Whitney U tests.

Results

302 patients were reviewed. The median time to follow-up, defined as from date of diagnosis to last clinic visit or to transplantation date, was 98 months (IQR = 87). The mean age at diagnosis was 38 (SD = 15.1) years; 54% of patients were male. A total of 224 patients had IBD (74%). Of the 302 patients, 80 patients (26%) had evidence of hepatolithiasis on US or MRI. Patients with hepatolithiasis were more likely to be younger (37.4 vs 39.1, p = 0.025), male (65% vs. 50%, p = 0.021), and have large duct disease (99% vs. 88%, p = 0.004). Imaging report review revealed patients with hepatolithiasis were more likely to have intrahepatic biliary thickening (76% vs. 45%, p < 0.001), extrahepatic biliary thickening (69% vs. 50%, p = 0.003), focal biliary dilation (96% vs. 78%, p < 0.001) and disease characterised by more reported strictures on qualitative imaging report review (89% vs 69%, p < 0.001). Concomitant presence of cholelithiasis was greater in the hepatolithiasis vs. the non-hepatolithiasis group (45% vs. 19%, p < 0.001). There was no significant difference in the prevalence of hepatic or portal venous thrombosis in both groups. Patients with hepatolithiasis more likely have experienced acute ascending cholangitis (50% vs. 20%, p < 0.001) and need for ERCP (50% vs. 35%, p = 0.020). CCA was numerically higher in the hepatolithiasis group (8.75% vs. 4%, p = 0.1). Patients with hepatolithiasis received transplant more frequently (26.3% vs 12.2%, p < 0.001) with no significant difference in mortality.

Conclusions

Hepatolithiasis is common in PSC and associated with an increased clinical and radiologic disease burden.

Funding Agencies

None

Fate of the liver in the survivors of adult heart transplant for a failing Fontan circulation

The Fontan circulation has inherent long-term vulnerabilities such that adult Fontan patients now comprise the largest, most rapidly growing subgroup of adult congenital heart disease referred for transplant assessment. Almost all have Fontan Associated Liver Disease (FALD). There is an absence of mid to late hepatic outcome data after heart transplant alone. Therefore, we analyzed outcomes of survivors of heart only transplant in patients with failing Fontan circulation. Including all 10 of our adult Fontan patients surviving >1 year after isolated heart transplant, we report evolution of their clinical features, bloodwork, hemodynamic data, and liver ultrasound findings over a median of 4.7 years. Nonprogression of FALD, resolution of ascites and freedom from hepatocellular carcinoma in the mid-term highlight the outcomes in this selected group once normal cardiac output and venous pressures are established by heart transplant.

1141 Robotic Assisted Surgery in Horseshoe Kidneys: A Safety and Feasibility Multicentre Case Series

Introduction

Horseshoe kidneys (HSK) are the most common renal fusion abnormality. However, they are only present in 0.2% of the population. Due to anatomical variation in vasculature, ectopia and malrotation, surgery has traditionally been performed via an open approach. We aimed to assess the safety and feasibility of robot-assisted surgery for HSK.

Method

Six patients (four female, two male) with HSKs were operated on between 2016 and 2019 across two high-volume centres by high-volume surgeons. All operations were robot-assisted, with three partial nephrectomies and one nephroureterectomy for renal masses and two benign nephrectomies for non-functioning kidneys. 3D reconstruction using CT renal angiograms was used to help identify vasculature and tumour location (where appropriate).

Results

The median age was 53 years (IQR 47-58.3) and the median BMI was 25 (IQR 25-25.8). Median tumour size in the four patients with renal masses was 35.5 mm (IQR 25.3-44.8). Median console time was 120 minutes (IQR 117-172.5) and the median estimated blood loss was 150 mL (IQR 112.5-262.5). The median pre-operative eGFR was 76 (IQR 70-86.5) and median post-operative eGFR was 65.5 (IQR 59.3-80.8). All operations were uneventful, there were no perioperative transfusions and no complications reported. Length of stay was two days for all patients.

Conclusions

We report the largest series of mixed robotic-assisted surgery on HSK. Robotic surgery is safe and feasible for HSK in high-volume centres with acceptable perioperative outcomes. Further prospective, longer-term, multi-centre studies are required to evaluative if robotic surgery for HSK is superior to open surgery.

Recurrent Primary Sclerosing Cholangitis: Current Understanding, Management, and Future Directions

Patients with primary sclerosing cholangitis (PSC) constitute 5 to 15% of patients listed for liver transplantation worldwide. Although post-transplant outcomes are favorable, recurrent PSC (rPSC) occurs in an important subset of patients, with higher prevalence rates reported with increasing time from transplant. Given its association with poor graft outcomes and risk of retransplant, effort has been made to understand rPSC, its pathophysiology, and risk factors. This review covers these facets of rPSC and focuses on implicated risk factors including pretransplant recipient characteristics, inflammatory bowel-disease-related factors, and donor-specific and transplant-specific factors. Confirming a diagnosis of rPSC requires thoughtful consideration of alternative etiologies so as to ensure confidence in diagnosis, management, subsequent risk assessment, and counseling for patients. Unfortunately, no cure exists for rPSC; however, future large-scale efforts are underway to better characterize the natural history of rPSC and its associated risk factors with hopes of identifying potential key targets for novel therapies.

Single Topic Conference on Autoimmune Liver Disease from the Canadian Association for the Study of the Liver

Autoimmune liver disease (AILD) spans a spectrum of chronic disorders affecting the liver parenchyma and biliary system. Three main categories of AILD are autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC). This review condenses the presentation and discussions of the Single Topic Conference (STC) on AILD that was held in Ottawa, Ontario, in November 2019. We cover generalities regarding disease presentation and clinical diagnosis; mechanistic themes; treatment paradigms; clinical trials, including approaches and challenges to new therapies; and looking beyond traditional disease boundaries. Although these diseases are considered autoimmune, the etiology and role of environmental triggers are poorly understood. AILDs are progressive and chronic conditions that affect survival and quality of life. Advances have been made in PBC treatment because second-line treatments are now available (obeticholic acid, bezafibrate); however, a significant proportion still present suboptimal response. AIH treatment has remained unchanged for several decades, and data suggest that fewer than 50% of patients achieve a complete response and as many as 80% develop treatment-related side effects. B-cell depletion therapy to treat AIH is in an early stage of development and has shown promising results. An effective treatment for PSC is urgently needed. Liver transplant remains the best option for patients who develop decompensated cirrhosis or hepatocellular carcinoma within specific criteria, but recurrent AILD might occur. Continued efforts are warranted to develop networks for AILD aimed at assessing geo-epidemiological, clinical, and biochemical differences to capture the new treatment era in Canada.

Goals of Treatment for Improved Survival in Primary Biliary Cholangitis: Treatment Target Should Be Bilirubin Within the Normal Range and Normalization of Alkaline Phosphatase

INTRODUCTION

In primary biliary cholangitis (PBC), bilirubin and alkaline phosphatase (ALP) are widely established as independent predictors of prognosis. Current treatment goals do not aim for normalization of surrogate markers because their association with survival has not been defined.

METHODS

The patient cohort from the GLOBAL PBC Study Group was used, comprising of long-term follow-up data from European and North American centers. Ursodeoxycholic acid-treated and untreated patients with bilirubin levels ≤1 × upper limit of normal (ULN) at baseline or 1 year were included. The association of normal ALP with transplant-free survival was assessed in a subgroup with ALP ≤1.67 × ULN at 1 year. Optimal thresholds of bilirubin and ALP to predict liver transplantation (LT) or death were evaluated.

RESULTS

There were 2,281 patients included in the time zero cohort and 2,555 patients in the 1-year cohort. The bilirubin threshold with the highest ability to predict LT or death at 1 year was 0.6 × ULN (hazard ratio 2.12, 95% CI 1.69-2.66, P < 0.001). The 10-year survival rates of patients with bilirubin ≤0.6 × ULN and >0.6 × ULN were 91.3% and 79.2%, respectively (P < 0.001). The risk for LT or death was stable below the bilirubin levels of 0.6 × ULN, yet increased beyond this threshold. Ursodeoxycholic acid-induced reduction in bilirubin below this threshold was associated with an 11% improvement in 10-year survival. Furthermore, ALP normalization was optimal, with 10-year survival rates of 93.2% in patients with ALP ≤ 1 × ULN and 86.1% in those with ALP 1.0-1.67 × ULN.

DISCUSSION

Attaining bilirubin levels ≤0.6 × ULN or normal ALP are associated with the lowest risk for LT or death in patients with PBC. This has important implications for treatment targets.

Methylation signatures in peripheral blood are associated with marked age acceleration and disease progression in patients with primary sclerosing cholangitis

Background & Aims

A DNA methylation (DNAm) signature derived from 353 CpG sites (the Horvath clock) has been proposed as an epigenetic measure of chronological and biological age. This epigenetic signature is accelerated in diverse tissue types in various disorders, including non-alcoholic steatohepatitis, and is associated with mortality. Here, we assayed whole blood DNAm to explore age acceleration in patients with primary sclerosing cholangitis (PSC).

Methods

Using the MethylationEPIC BeadChip (850K) array, DNAm signatures in whole blood were analyzed in 36 patients with PSC enrolled in a 96-week trial of simtuzumab (Ishak F0-1, n = 13; F5-6, n = 23). Age acceleration was calculated as the difference between DNAm age and chronological age. Comparisons between patients with high and low age acceleration (≥ vs. < the median) were made and Cox regression evaluated the association between age acceleration and PSC-related clinical events (e.g. decompensation, cholangitis, transplantation).

Results

Age acceleration was significantly higher in patients with PSC compared to a healthy reference cohort (median, 11.1 years, p <2.2 × 10^-16). In PSC, demographics, presence of inflammatory bowel disease, and ursodeoxycholic acid use were similar between patients with low and high age acceleration. However, patients with high age acceleration had increased serum alkaline phosphatase, gamma glutamyltransferase, alanine aminotransferase, enhanced liver fibrosis test scores, and greater hepatic collagen and α-smooth muscle actin expression on liver biopsy (all p <0.05). Moreover, patients with high age acceleration had an increased prevalence of cirrhosis (89% vs. 39%; p = 0.006) and greater likelihood of PSC-related events (hazard ratio 4.19; 95% CI 1.15–15.24).

Conclusion

This analysis of blood DNAm profiles suggests that compared with healthy controls, patients with PSC – particularly those with cirrhosis - exhibit significant acceleration of epigenetic age. Future studies are required to evaluate the prognostic implications and effect of therapies on global methylation patterns and age acceleration in PSC.

Lay summary

An epigenetic clock based on DNA methylation has been proposed as a marker of age. In liver diseases such as non-alcoholic steatohepatitis, age acceleration based on this epigenetic clock has been observed. Herein, we show that patients with primary sclerosing cholangitis have marked age acceleration, which is further accentuated by worsening fibrosis. This measure of age acceleration could be a useful marker for prognostication or risk stratification in primary sclerosing cholangitis.

•

A peripheral blood DNA methylation (DNAm) score identifies age acceleration in PSC patients vs. healthy controls.

•

PSC patients with high age acceleration had significantly more PSC-related events than those with low age acceleration.

•

These findings may enable stratification of at-risk PSC patients based on a DNAm score from peripheral blood.

Fibrosis stage is an independent predictor of outcome in primary biliary cholangitis despite biochemical treatment response

BACKGROUND

Fibrosis stage predicts prognosis in patients with chronic liver disease independent of aetiology, although its precise role in risk stratification in patients with primary biliary cholangitis (PBC) remains undefined.

AIM

To assess the utility of baseline fibrosis stage in predicting long-term outcomes in the context of biochemical risk stratification METHODS: In a large and globally representative cohort of patients with PBC, liver biopsies performed from 1980 to 2014 were evaluated. The predictive ability of histologic fibrosis stage in addition to treatment response at 1 year (Toronto/Paris-II criteria), as well as non-invasive markers of fibrosis (AST/ALT ratio [AAR], AST to platelet ratio index [APRI], FIB-4), for transplant-free survival was assessed with Cox proportional-hazards models.

RESULTS

There were 1828 patients with baseline liver biopsy. Advanced histologic fibrosis (stage 3/4) was an independent predictor of survival in addition to non-invasive measures of fibrosis with the hazard ratios ranging from 1.59 to 2.73 (P < .001). Patients with advanced histologic fibrosis stage had worse survival despite biochemical treatment response, with a 10-year survival of 76.0%-86.6% compared to 94.5%-95.1% depending on the treatment response criteria used. Poor correlations were observed between non-invasive measures of fibrosis and histologic fibrosis stage.

CONCLUSION

Assessment of fibrosis stage grants prognostic value beyond biochemical treatment response at 1 year. This highlights the need to incorporate fibrosis stage in individual risk stratification in patients with PBC, partly to identify those that may derive benefit from novel therapies.

The Nonsteroidal Farnesoid X Receptor Agonist Cilofexor (GS-9674) Improves Markers of Cholestasis and Liver Injury in Patients With Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) represents a major unmet medical need. In a phase II double-blind, placebo-controlled study, we tested the safety and efficacy of cilofexor (formerly GS-9674), a nonsteroidal farnesoid X receptor agonist in patients without cirrhosis with large-duct PSC. Patients were randomized to receive cilofexor 100 mg (n = 22), 30 mg (n = 20), or placebo (n = 10) orally once daily for 12 weeks. All patients had serum alkaline phosphatase (ALP) > 1.67 × upper limit of normal and total bilirubin ≤ 2 mg/dL at baseline. Safety, tolerability, pharmacodynamic effects of cilofexor (serum C4 [7α-hydroxy-4-cholesten-3-one] and bile acids), and changes in liver biochemistry and serum fibrosis markers were evaluated. Overall, 52 patients were randomized (median age 43 years, 58% male, 60% with inflammatory bowel disease, 46% on ursodeoxycholic acid). Baseline median serum ALP and bilirubin were 348 U/L (interquartile range 288-439) and 0.7 mg/dL (0.5-1.0), respectively. Dose-dependent reductions in liver biochemistry were observed. At week 12, cilofexor 100 mg led to significant reductions in serum ALP (median reduction -21%; P = 0.029 versus placebo), gamma-glutamyl transferase (-30%; P < 0.001), alanine aminotransferase (ALT) (-49%; P = 0.009), and aspartate aminotransferase (-42%; P = 0.019). Cilofexor reduced serum C4 compared with placebo; reductions in bile acids were greatest with 100 mg. Relative reductions in ALP were similar between ursodeoxycholic acid-treated and untreated patients. At week 12, cilofexor-treated patients with a 25% or more relative reduction in ALP had greater reductions in serum alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, tissue inhibitor of metalloproteinase 1, C-reactive protein, and bile acids than nonresponders. Adverse events were similar between cilofexor and placebo-treated patients. Rates of grade 2 or 3 pruritus were 14% with 100 mg, 20% with 30 mg, and 40% with placebo. Conclusion: In this 12-week, randomized, placebo-controlled study, cilofexor was well tolerated and led to significant improvements in liver biochemistries and markers of cholestasis in patients with PSC.

Effects of Age and Sex of Response to Ursodeoxycholic Acid and Transplant-free Survival in Patients With Primary Biliary Cholangitis

BACKGROUND & AIMS

Primary biliary cholangitis (PBC) predominantly affects middle-aged women; there are few data on disease phenotypes and outcomes of PBC in men and younger patients. We investigated whether differences in sex and/or age at the start of ursodeoxycholic acid (UDCA) treatment are associated with response to therapy, based on biochemical markers, or differences in transplant-free survival.

METHODS

We performed a longitudinal retrospective study of 4355 adults in the Global PBC Study cohort, collected from 17 centers across Europe and North America. Patients received a diagnosis of PBC from 1961 through 2014. We evaluated the effects of sex and age on response to UDCA treatment (based on GLOBE score) and transplant-free survival using logistic regression and Cox regression analyses, respectively.

RESULTS

Male patients were older at the start of treatment (58.3±12.1 years vs 54.3±11.6 years for women; P<.0001) and had higher levels of bilirubin and lower circulating platelet counts (P<.0001). Younger patients (45 years or younger) had increased serum levels of transaminases than older patients (older than 45 years). Patients older than 45 years at time of treatment initiation had increased odds of a biochemical response to UDCA therapy, based on GLOBE score, compared to younger patients. The greatest odds of response to UDCA were observed in patients older than 65 years (odds ratio compared to younger patients 45 years or younger, 5.48; 95% CI, 3.92-7.67; P<.0001). Risk of liver transplant or death (compared to a general population matched for age, sex, and birth year) decreased significantly with advancing age: hazard ratio for patients 35 years or younger, 14.59 (95% CI, 9.66-22.02) vs hazard ratio for patients older than 65 years, 1.39 (95% CI, 1.23-1.57) (P<.0001). On multivariable analysis, sex was not independently associated with response or transplant-free survival.

CONCLUSION

In longitudinal analysis of 4355 adults in the Global PBC Study, we associated patient age, but not sex, with response to UDCA treatment and transplant-free survival. Younger age at time of treatment initiation is associated with increased risk of treatment failure, liver transplant, and death.

Milder disease stage in patients with primary biliary cholangitis over a 44-year period: A changing natural history

Changes over time in the presenting features and clinical course of patients with primary biliary cholangitis are poorly described. We sought to describe temporal trends in patient and disease characteristics over a 44-year period across a large international primary biliary cholangitis cohort of 4,805 patients diagnosed between 1970 and 2014, from 17 centers across Europe and North America. Patients were divided into five cohorts according to their year of diagnosis: 1970-1979 (n = 143), 1980-1989 (n = 858), 1990-1999 (n = 1,754), 2000-2009 (n = 1,815), and ≥2010 (n = 235). Age at diagnosis, disease stage, response to ursodeoxycholic acid, and clinical outcomes were compared. Mean age at diagnosis increased incrementally by 2-3 years per decade from 46.9 ± 10.1 years in the 1970s to 57.0 ± 12.1 years from 2010 onward (P < 0.001). The female to male ratio (9:1) and antimitochondrial antibody positivity (90%) were not significantly variable. The proportion of patients presenting with mild biochemical disease (according to Rotterdam staging) increased from 41.3% in the 1970s to 72.2% in the 1990s (P < 0.001) and remained relatively stable thereafter. Patients with a mild histological stage at diagnosis increased from 60.4% (1970-1989) to 76.5% (1990-2014) (P < 0.001). Correspondingly, response to ursodeoxycholic acid according to Paris-I criteria increased; 51.7% in the 1970s and 70.5% in the 1990s (P < 0.001). Recent decades were also characterized by lower decompensation rates (18.5% in the 1970s to 5.8% in the 2000s, P < 0.001) and higher 10-year transplant-free survival (48.4%, 68.7%, 79.7%, and 80.1% for each respective cohort; P < 0.001).

CONCLUSION

In recent decades, a pattern of primary biliary cholangitis presentation consistent with an older age at diagnosis alongside reduced disease severity has been noted; the observed trends may be explained by an increase in routine testing of liver function and/or a changing environmental trigger. (Hepatology 2018;67:1920-1930).

Neutralization of IL-15 abrogates experimental immune-mediated cholangitis in diet-induced obese mice

Obesity is a global epidemic affecting chronic inflammatory diseases. Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease that can occur as an extraintestinal manifestation of inflammatory bowel disease (IBD). Previously we reported that patients with PSC who are obese have a higher risk of advanced liver disease. Currently it is unknown how obesity accelerates or worsens PSC. We evaluated the progression of PSC in an antigen-driven cholangitis mouse model of diet-induced obesity. Obesity was induced in our murine model of immune-mediated cholangitis (OVAbil). OVAbil mice were fed standard chow or high-fat/sucrose diet for twelve weeks followed by induction of biliary inflammation by OVA-specific T cell transfer. Histopathological damage in portal tracts was scored and serum collected. Neutralizing antibodies against IL-15 were administered daily until study termination. Obese mice developed exacerbated liver inflammation and damage. Immune cell phenotyping in liver revealed greater numbers of neutrophils and CD8+ T cells in obese mice. Higher levels of cytokines and chemokines were found in obese mice with cholangitis. Immuno-neutralizing antibodies against IL-15 greatly attenuated cholangitis in obese mice. Obesity exacerbated experimental PSC in part by overproduction of IL-15. Timely targeting of IL-15 may slow the progression of PSC.

The transition from phase II to phase III studies

6514

Background: Phase II trials are performed to detect potential anti-tumor effects of a new treatment and should be used to decide whether to proceed to a phase 3 trial or not. However, many phase 2 trials never lead to a phase 3 trial despite encouraging results. Here we sought to determine how often (i) positive phase 2 trials have led to phase 3 trials, and (ii) how often phase 2 trials were designed to lead to a phase 3 trial. Methods: We reviewed 200 phase 2 trials, presented at ASCO meetings in 1995–1996, and 2006, selecting randomly 20 abstracts with encouraging results for 5 cancer sites (breast, lung, GI, GU, Gyn) in each time period. For those presented in 1995–1996, we searched systematically for subsequent randomized studies where one treatment arm was similar to that in the phase 2 study. For those presented in 2006, a questionnaire was sent to authors asking whether they recommend evaluating the regimen in a phase 3 trial, whether a phase 3 trial is planned and whether resources (budget, patients, drugs) are available to conduct a phase 3 trial. Results: Ten years after presenting phase 2 trials with positive results, only 13 regimens have been evaluated in a phase 3 trial. Of 100 investigators who presented a phase 2 trial in 2006, 42 returned the questionnaire, 36 confirmed that the results met criteria of efficacy and 25 thought the regimen should be evaluated in a phase 3 trial. Only 10 investigators plan to undertake a phase 3 trial, and 8 stated they had resources to do so. Reasons for not planning a phase 3 study included insufficient efficacy (7), insufficient access to patients (5) or financial support (5), lack of interest from colleagues (6), and lack of support from the company (8). Conclusions: Few (∼13%) phase 2 trials with promising activity are followed by phase 3 trials and this is not increasing with time. Reasons include lack of resources such as money, drugs and patients. Many of these limitations are known when planning the phase 2 study, implying that many phase 2 trials are not planned as precursors of phase 3 trials. Resources spent on such trials would be better applied to practice-changing phase 3 trials.

No significant financial relationships to disclose.

The effect of sodium salicylate on the rat embryo in culture: an in vitro model for the morphological assessment of teratogenicity

The optimum teratogenic dose of subcutaneously administered sodium salicylate was determined in vivo at 9.5 days of gestation. Fetuses from rats injected with this dose at 9.5 days were examined at 11.5 days and its propensities for producing resorption as well as deformities noted. Next, maternal serum levels 3-3.5 hours and 18.5 hours after salicylate injection were determined. Having established the feasibility of determining an effect due to salicylate at 11.5 days, after injection at 9.5 days, the following experiments were performed in vitro in animals cultured between 9.5 and 11.5 days by the method of New et al. (1976a): (1) Sodium salicylate was added to the culture serum, at levels equivalent to those obtained 3-3.5 hours after maternal injection of the optimum teratogenic dose, for 24 of the 48 hours culture period. (2) Rats were cultured for the first 24 hours of the 48 hours culture period in serum taken from rats injected 3.5 hours previously with the optimum teratogenic dose. (3) Rats were cultured for 24 out of 48 hours in serum from animals which had been injected with the optimum teratogenic dose 18.5 hours before bleeding. (4) Rats were cultured for 24 out of 48 hours in serum containing salicylate added to make up levels normally associated with (3). (5) A control culture was performed. The experiment indicates great similarity between the results obtained from animals cultured in serum with salicylate added and results from culture in serum of salicylate treated rats. It appears therefore that sodium salicylate - acting directly on the feto-placental unit - is the active teratogen rather than any of its metabolites.

The effect of trypan blue on the development of the ferret and rat

The teratogenic effects of trypan blue given to pregnant rats and ferrets at equivalent stages of embryonic development are described. In the rat the well known teratogenicity of the dye at 8.5 days of gestation and the surprising cessation of teratogenic effect at 11.5 days (20+ somites) is confirmed. In the ferret the drug is teratogenic both at 13 and 18 days of gestation though the principal abnormalities seen are different to those described in the rat. It has been suggested that the teratogenic action of trypan blue in rats is due to an interference in the function of the yolk sac which is an organ of histiotrophic nutrition and provides the principal source of nutrition for the 8.5-day embryo that is largely replaced by a functional chorio-allantoic placenta after 11.5 days of gestation. In ferrets histiotrophic nutrition does not involve an inverted yolk sac placental system. In this species endometrial symplasma provides histiotroph which is ingested by the invading trophoblast. Histiotrophic nutrition is still of great importance at 18 days and morphological evidence indicates that chorio-allantoic placentation becomes important by about 20 days (35+ somites).