Patients and methods
Study design and cohort
This is a retrospective study of prospectively collected data within the Italian PBC Registry, an ongoing, non-interventional, multicentre, observational cohort study that monitors patients with PBC in Italy. All adult patients who had received a diagnosis of PBC consecutively starting OCA treatment from 38 Italian centres between September 2017 and February 2020 were screened for the study. All patients who had taken at least 1 dose of OCA, and with an overall follow-up of at least 12 months (therefore, having started OCA not later than February 2019), were included in the study. Patients who had been previously enrolled in a sponsored trial with OCA were excluded. Patients receiving off-label fibrate therapy on stable treatment for at least 6 months at the time of starting OCA were not excluded. Hospitals with a dedicated autoimmune liver diseases outpatient clinic were defined as ’tertiary centres’; those with a general hepatology outpatient clinic were defined as ‘secondary centres’.
Diagnosis of PBC and ‘definite’ PBC-AIH overlap syndrome were defined according to European Association for the Study of the Liver (EASL) guidelines.
[1]- Hirschfield G.M.
- Beuers U.
- Corpechot C.
- Invernizzi P.
- Jones D.E.
- Marzioni M.
- et al.
EASL Clinical Practice Guidelines: the diagnosis and management of patients with primary biliary cholangitis.
The diagnosis of PBC-AIH overlap syndrome was histologically confirmed in all cases and all patients were on a stable immunosuppressive treatment for at least 6 months. Diagnosis of liver cirrhosis was based on clinical presentation (at ultrasound: surface nodularity, caudate hypertrophy, splenomegaly; at upper endoscopy: gastroesophageal varices), or histological evaluation.
Indications to OCA treatment are reported in
Appendix S1.
We defined the Overall Cohort (OC) as all patients who had received at least 1 dose of OCA and had at least 12 months of follow-up. The Treatment Completer Cohort (TCC) was defined as all patients who completed the treatment period of 6 or 12 months for the analysis at 6 or 12 months, respectively. The primary efficacy analysis was carried out on both the OC and TCC populations. Safety and tolerability were analysed in the OC population only.
The study was conducted in accordance with the Declaration of Helsinki guidelines and the principles of good clinical practice. All participants to the Italian PBC Registry provided written informed consent. The study was approved by the University of Milan-Bicocca research ethics committee (Study name: PBC322), coordinator of the Italian National Registry and by the Research and Development Department of each collaborating hospital.
Data source
Data were captured using baseline and follow-up case record forms (CRFs), completed by physicians in each collaborating centre. Demographic, clinical, and biochemical data were collected at baseline (immediately before starting OCA therapy), and at 6 and 12 months of treatment during follow-up visits. Management of OCA therapy was tailored for each patient and clinical decisions were taken independently by physicians based on the drug package insert. Data on OCA dose adjustment and OCA discontinuation were systematically collected.
Pruritus was systematically assessed at baseline and at every follow-up visit. Pruritus was classified as mild, moderate, or severe as follows: mild, pruritus of mild intensity or localised; moderate, pruritus of moderate intensity or diffuse but intermittent; severe, pruritus of severe intensity or diffuse and continuous. Moreover, pruritus was classified as ‘de novo’ if it occurred after the start of OCA treatment, or as ‘worsening’ if present at baseline but increased on OCA therapy. Other adverse events were not systematically assessed but registered when they led to permanent drug discontinuation.
Completed CRFs underwent quality control (QC) for completeness and accuracy at the University of Milan-Bicocca, Milan and University Campus Bio Medico, Rome. Missing, inaccurate, or implausible data were systematically queried with the treating physicians. Data that passed QC were uploaded into a bespoke database, collecting clinical and biochemical data at each follow-up time point. The database is an electronic data capture (EDC) system with an e-CRF developed for the purpose of this study and other projects on the Italian PBC Registry. The EDC system runs on a server maintained by a dedicated Clinical Research Organisation. The EDC system allows research staff in collaborating centres to log in from any National Health Service computer to view information about participants recruited from their own centres and to complete e-CRFs and upload the results of medical investigations directly into the database.
Study endpoints
The ‘primary endpoint’ was the biochemical response at 6 and 12 months of OCA therapy using the Poise definition of biochemical response: (1) ALP<1.67/upper limit of normal (ULN) with a reduction of ≥15% from baseline and a normal total bilirubin level, as applied in the registrative trial of OCA (
Poise criteria).
[5]- Nevens F.
- Andreone P.
- Mazzella G.
- Strasser S.I.
- Bowlus C.
- Invernizzi P.
- et al.
A placebo-controlled trial of obeticholic acid in primary biliary cholangitis.
The ‘secondary endpoint’ was the biochemical response at 6 and 12 months of OCA therapy according to the following criteria: alanine aminotransferase (ALT), ALP, and bilirubin within the normal (
normal range criteria), as normalisation of liver biochemistry has been recently proposed as the new therapeutic target in PBC.
[8]- Murillo Perez C.F.
- Harms M.H.
- Lindor K.D.
- van Buuren H.R.
- Hirschfield G.M.
- Corpechot C.
- et al.
Goals of treatment for improved survival in primary biliary cholangitis: treatment target should be bilirubin within the normal range and normalization of alkaline phosphatase.
Other efficacy endpoints included variation of ALP, gamma-glutamyltransferase (GGT), ALT, aspartate aminotransferase (AST), and total bilirubin levels at 6 and 12 months of OCA therapy.
We defined missed up-titrations when patients were taking 5 mg/day at 12 months even though they had an ALP ≥1.5/UNL at 6 months and no pruritus.
Assessment of safety and side effects included systematic evaluation of pruritus, and collection of adverse events and laboratory abnormalities that led to treatment discontinuation.
Statistical analysis
Continuous variables were described by mean, standard deviation, and as median and IQRs in case they showed a skewed distribution with significant departure from the normal distribution. To account for inter-laboratory variability, ALP, GGT, ALT, AST, and total bilirubin were expressed as ratios of their respective ULN. Categorical variables were described by absolute frequencies and percentages. To compare groups, we used the χ
2 test for categorical variables (or Fisher exact test in the case of sparse data) and the Student
t test for continuous variables (or Wilcoxon test when a significant departure from normality was detected). The analysis of factors associated with an increased risk of no response after 12 months of OCA therapy was carried out by reporting risk ratios (RR) with 95% CIs, and performed by means of Poisson regression models with robust error variance, as described by Zou
et al.[9]A modified Poisson regression approach to prospective studies with binary data.
Age at OCA start (which was collinear with age and age at PBC diagnosis), and all variables associated at univariate analysis with a value of
p <0.10 entered the multivariate model. All analyses were undertaken using R version 3.6.1 (R Foundation for Statistical Computing, Vienna, Austria;
https://www.R-project.org/).
Discussion
Real-world studies enable evaluation of treatment effectiveness, safety, and prescribing patterns in routine clinical practice and represent an important complement to the results obtained from clinical trials. Our data, obtained in a large cohort of patients with a follow-up of 12 months, confirm in a real-world context that OCA is an effective and well-tolerated treatment option for patients with PBC who are non-responding to or non-tolerating UDCA. More importantly, the present study provides important novel evidence concerning response rates and side effects in patients with cirrhosis and those with overlap PBC-AIH, who had been either under-represented or excluded, respectively, from RCTs with OCA.
In the phase III registrative trial, 12-month treatment of PBC patients who were non-responders to UDCA
10- Parés A.
- Caballería L.
- Rodés J.
Excellent long-term survival in patients with primary biliary cirrhosis and biochemical response to ursodeoxycholic acid.
, 11- Corpechot C.
- Abenavoli L.
- Rabahi N.
- Chrétien Y.
- Andréani T.
- Johanet C.
- et al.
Biochemical response to ursodeoxycholic acid and long-term prognosis in primary biliary cirrhosis.
, 12- Kuiper E.M.M.
- Hansen B.E.
- de Vries R.A.
- den Ouden-Muller J.W.
- van Ditzhuijsen T.J.
- Haagsma E.B.
- et al.
Improved prognosis of patients with primary biliary cirrhosis that have a biochemical response to ursodeoxycholic acid.
, 13- Kumagi T.
- Guindi M.
- Fischer S.E.
- Arenovich T.
- Abdalian R.
- Coltescu C.
- et al.
Baseline ductopenia and treatment response predict long-term histological progression in primary biliary cirrhosis.
, 14- Corpechot C.
- Chazouillères O.
- Poupon R.
Early primary biliary cirrhosis: biochemical response to treatment and prediction of long-term outcome.
, 15- Lammers W.J.
- Hirschfield G.M.
- Corpechot C.
- Nevens F.
- Lindor K.D.
- Janssen H.L.
- et al.
Development and validation of a scoring system to predict outcomes of patients with primary biliary cirrhosis receiving ursodeoxycholic acid therapy.
, 16- Carbone M.
- Sharp S.J.
- Flack S.
- Paximadas D.
- Spiess K.
- Adgey C.
- et al.
The UK-PBC risk scores: derivation and validation of a scoring system for long-term prediction of end-stage liver disease in primary biliary cholangitis.
led to biochemical response in 46%, 47%, and 10% in the OCA titration, OCA 10 mg fixed-dose and placebo arms, respectively.
[5]- Nevens F.
- Andreone P.
- Mazzella G.
- Strasser S.I.
- Bowlus C.
- Invernizzi P.
- et al.
A placebo-controlled trial of obeticholic acid in primary biliary cholangitis.
Pruritus was the main side effect and the principal cause of OCA discontinuation. The 3-year interim data from the open-label extension demonstrated that prolonged OCA treatment is associated with durable improvements in markers of cholestasis without new safety signals.
[6]- Trauner M.
- Nevens F.
- Shiffman M.L.
- Drenth J.P.H.
- Bowlus C.L.
- Vargas V.
- et al.
Long-term efficacy and safety of obeticholic acid for patients with primary biliary cholangitis: 3-year results of an international open-label extension study.
Nevertheless, to date, there have been no sizeable cohort studies reporting data concerning OCA therapy in a real-world context, where patient characteristics are more heterogeneous with respect to subphenotypes (
e.g. overlap PBC-AIH, cirrhosis) and drug schedule (
e.g. starting dose, criteria for up-titration or discontinuation) may be less rigid and more personalised by each treating physician. Indeed, only 1 real-world experience with OCA has been reported very recently, carried out in a small cohort of 64 patients, of which only 36 with at least 12 months of observation.
[7]- Roberts S.B.
- Ismail M.
- Kanagalingam G.
- Mason A.L.
- Swain M.G.
- Vincent C.
- et al.
Real-world effectiveness of obeticholic acid in patients with primary biliary cholangitis.
The present study analysed 191 patients from 38 Italian secondary and tertiary centres. The population enrolled was similar to that described in the Poise trial
[5]- Nevens F.
- Andreone P.
- Mazzella G.
- Strasser S.I.
- Bowlus C.
- Invernizzi P.
- et al.
A placebo-controlled trial of obeticholic acid in primary biliary cholangitis.
with the following exceptions: (1) 61 patients (32%) in our cohort had cirrhosis (clinically and/or histologically), compared with an estimated 20% in the Poise trial based on transient elastography, which was, however, performed only in 43% of the study population; (2) 28 patients (15%) had a histologically confirmed diagnosis of overlap PBC-AIH, which was an exclusion criterion in the POISE study;
[5]- Nevens F.
- Andreone P.
- Mazzella G.
- Strasser S.I.
- Bowlus C.
- Invernizzi P.
- et al.
A placebo-controlled trial of obeticholic acid in primary biliary cholangitis.
(3) 50 patients (26%) in our cohort had abnormal bilirubin levels at baseline, compared with 18 patients (8%) in the Poise cohort.
[5]- Nevens F.
- Andreone P.
- Mazzella G.
- Strasser S.I.
- Bowlus C.
- Invernizzi P.
- et al.
A placebo-controlled trial of obeticholic acid in primary biliary cholangitis.
Because liver cirrhosis, overlap PBC-AIH, and abnormal bilirubin are well-known predictors of worse prognosis in PBC,
[8]- Murillo Perez C.F.
- Harms M.H.
- Lindor K.D.
- van Buuren H.R.
- Hirschfield G.M.
- Corpechot C.
- et al.
Goals of treatment for improved survival in primary biliary cholangitis: treatment target should be bilirubin within the normal range and normalization of alkaline phosphatase.
,[9]A modified Poisson regression approach to prospective studies with binary data.
,[17]- Carey E.J.
- Ali A.H.
- Lindor K.D.
Primary biliary cirrhosis.
the present study population is more difficult to treat, as expected in an early post-marketing real-world context, where the most severely affected patients
[3]- Carbone M.
- Mells G.F.
- Pells G.
- Dawwas M.F.
- Newton J.L.
- Heneghan M.A.
- et al.
Sex and age are determinants of the clinical phenotype of primary biliary cirrhosis and response to ursodeoxycholic acid.
,[18]- Cristoferi L.
- Nardi A.
- Ronca V.
- Invernizzi P.
- Mells G.
- Carbone M.
Prognostic models in primary biliary cholangitis.
are frequently granted the new therapeutic option first.
In our study, the benefit of OCA on liver biochemistry was evident in the whole cohort, with an overall reduction of ≅30% for ALP and ALT levels, and ≅10% reduction of bilirubin levels, at 12 months. We reported results for the cut-off ALP <1.67/ULN, as this is how UDCA response has been defined in the RCT Poise. This cut-off is, however, debatable. Given the strong correlation between ALP and histological features of biliary injury,
[4]- Carbone M.
- Nardi A.
- Flack S.
- Carpino G.
- Varvaropoulou N.
- Gavrila C.
- et al.
Pretreatment prediction of response to ursodeoxycholic acid in primary biliary cholangitis: development and validation of the UDCA Response Score.
,[13]- Kumagi T.
- Guindi M.
- Fischer S.E.
- Arenovich T.
- Abdalian R.
- Coltescu C.
- et al.
Baseline ductopenia and treatment response predict long-term histological progression in primary biliary cirrhosis.
,[19]- Carbone M.
- D’Amato D.
- Hirschfield G.M.
- Jones D.E.J.
- Mells G.F.
Letter: histology is relevant for risk stratification in primary biliary cholangitis.
it might be argued that the threshold should be the complete biochemical remission. Indeed, this has already been used in the Bezurso trial.
[20]- Corpechot C.
- Chazouillères O.
- Rousseau A.
- Le Gruyer A.
- Habersetzer F.
- Mathurin P.
- et al.
A placebo-controlled trial of bezafibrate in primary biliary cholangitis.
Recognising this on-going debate, we provide results also for the
normal range criteria, which highlighted an enormous unmet clinical need with only 11% of patients normalising ALP, ALT, and bilirubin in the OC analysis.
[21]- Gerussi A.
- D’Amato D.
- Cristoferi L.
- O’Donnell S.E.
- Carbone M.
- Invernizzi P.
Multiple therapeutic targets in rare cholestatic liver diseases: time to redefine treatment strategies.
Given limited healthcare budgets and the limited evidence of efficacy of this drug in some patients, with the assumption that patient-centred care must be fair and cost effective, these data should prompt cost-effective analysis.
One-third of patients in our cohort had cirrhosis, including 2 with Child-Pugh B function and 12 with gastro-oesophageal varices. The response rate was lower in the cirrhosis group in the OC analysis, owing to higher rate of drop-out and higher baseline bilirubin levels. Indeed, cirrhosis was not associated with non-response in the multivariate model corrected also for OCA discontinuation. Indeed, the degree of reduction of the liver biochemistry was comparable between patients with and without cirrhosis (12-month reduction was 29.4% and 34% for ALP, 30% and 31.4% for ALT, and 3.7% and 14.3% in patients with cirrhosis vs. those without cirrhosis, respectively, p = n.s. for all comparisons). Three patients with cirrhosis (2 with Child-Pugh B) experienced worsening liver function during OCA treatment. We believe OCA is effective in patients with cirrhosis providing the disease class is Child-Pugh A (97% of our cohort with cirrhosis), the treatment regimen is correct, and pruritus (the major cause for drop-out in this population) is monitored and appropriately prevented and/or managed.
In the majority of patients (60%), OCA was started and continued until the 12th month at 5 mg/day, and in only 35% it was up-titrated to 10 mg/day. Notably, in 10 patients, including 5 Child-Pugh A patients with cirrhosis, OCA was maintained at the dose of <5 mg/day
(5 mg/every other day, every 3 days) and 86% of patients with cirrhosis on 5 mg/day did not up-titrate despite preserved liver function and no adverse events. This choice is likely the result of a prudent real-world approach after the FDA warning about serious liver injury with OCA when the drug was incorrectly dosed in patients with moderate-to-decreased liver function.
Inadequate response was the reason for OCA up-titration at 6 months, and increasing to 10 mg partially recovered the suboptimal result on ALP levels in these patients. Of note, beyond the majority of patients with cirrhosis, also 45% of patients without cirrhosis eligible for up-titration did not up-titrate. Hopefully, more experience and continuing medical education will tackle this clinical gap.
Among the 28 patients with PBC-AIH overlap syndrome,
[24]- Chazouillères O.
- Wendum D.
- Serfaty L.
- Rosmorduc O.
- Poupon R.
Long term outcome and response to therapy of primary biliary cirrhosis–autoimmune hepatitis overlap syndrome.
82% had incomplete response to immunosuppression therapy with elevated transaminase (and ALP) despite stable immunosuppression and UDCA. After treatment with OCA, they showed a median ALT reduction of 38%, and 16 patients normalised the ALT levels at 6 months and maintained normalised ALT levels at 12 months (with a median 33% reduction of ALP). This might suggest an anti-inflammatory and/or immunomodulatory effect of OCA on the hepatitis component of the overlap syndrome. In alternative, OCA might improve the hepatitis component secondary to cholestasis. However, this deserves confirmation, as we cannot certainly exclude that the cholestasis and hepatitic activity non-responding to immunosuppression was surrogate of an aggressive phenotype of PBC.
The lower rate of OCA response observed in tertiary centres is not surprising, considering that tertiary centres included ounger patients, with more elevated liver biochemistry, and more likely to be on triple therapy with UDCA, fibrates, and OCA (rate of response ≅30%).
[25]- Vespasiani-Gentilucci U.
- Rosina F.
- Pace-Palitti V.
- Sacco R.
- Pellicelli A.
- Chessa L.
- et al.
Rate of non-response to ursodeoxycholic acid in a large real-world cohort of primary biliary cholangitis patients in Italy.
However, owing to the limited number of patients on triple therapy, further studies are needed to make conclusions on this category of patients.
Pruritus was the most common adverse event affecting one-quarter of the cohort, compared with 18% in the titration arm and 30% in the 10 mg arm in the Poise trial. Pruritus was classified as mild, moderate, or severe, rather than using a visual-analogue scale to detect clinically significant pruritus. The rate of OCA permanent discontinuation was slightly higher than that observed in the Poise trial (17% vs. 9%). The other side effects leading to treatment discontinuation did not have any clustering.
This study has some limitations. We did not collect all side effects experienced under OCA treatment and all the medications of pruritus adopted. This approach was aimed at reducing the burden of workload for clinicians therefore maximising the adhesion of many (secondary) centres. Consistent with this, we did not include the biochemical variables which were not routinely assessed at every control by all centres, such as platelets, serum albumin, and immunoglobulins in the database. We included patients who were already on off-label fibrate therapy and with overlap PBC-AIH syndrome, who can bias the rate of response of a ‘pure’ second-line PBC population. However, this allows to have a full understanding of the treatment burden in a real-world context.
In conclusion, the present study suggests that the results obtained by OCA in the registrative RCTs can be substantially reproduced in a real-world context in efficacy, safety, and tolerability, even if including patients with cirrhosis and overlap PBC-AIH. A careful approach is required in patients with cirrhosis who might need optimisation of pruritus control before starting OCA and over the treatment. Patients with PBC-AIH overlap might experience additional benefit in terms of improvement of hepatitis activity. If complete normalisation of the liver biochemistry is the new therapeutic target in PBC, a significant population of patients will likely require an adjunctive tertiary treatment.