Combination antiretroviral therapy improves recurrent primary biliary cholangitis following liver transplantation

1.1 Choice of repurposed HIV ART to treat HBRV infection

We evaluated HIV ART for activity against HBRV and found that reverse transcriptase inhibitors, such as tenofovir (TDF), and the HIV protease inhibitor lopinavir (LPR), can inhibit betaretrovirus activity in vitro.⁵ Others have reported that HIV integrase inhibitor raltegravir (RAL) exhibits broad spectrum activity against gammaretroviruses and betaretroviruses.¹² Accordingly, we evaluated the ability of RAL to inhibit pseudotyped particles containing either the HIV or HBRV integrase from expressing green fluorescent protein in vitro.¹³ We found that RAL inhibited HBRV reporter expression by 94%-97% at the EC50 and EC95 concentrations used for HIV (effective concentration of drug providing half-maximal or 95% inhibitory responses), suggesting that RAL should provide sufficient antiviral HBRV activity in patients at the 1200 mg daily dosing.¹²

In vivo studies using the NOD.c3c4 mouse model of PBC with MMTV cholangitis showed that combination of emtricitabine/tenofovir (FTC/TDF) and lopinavir boosted with ritonavir (LPRr) resulted in biochemical and histological improvement with amelioration of cholangitis.¹⁴ Others have reported that the FTC/TDF/LPRr regimen normalised hepatic biochemistry in a PBC patient with both HIV and HBRV co-infection.¹⁵ Accordingly, we used the same regimen in a randomised controlled for PBC patients unresponsive to UDCA but enrolment was discontinued prematurely because two thirds of subjects developed gastrointestinal intolerance to LPRr.⁹ Nevertheless, patients who continued to take FTC/TDF/LPRr in the open label extension study demonstrated significant and sustained biochemical responses to treatment.

Herein, we describe the clinical course of two liver transplant recipients with rPBC who were treated with different combination ART regimens. As we had not established the utility of prophylactic UDCA at the time, both patients received UDCA once rPBC was diagnosed.² Also, the combination ART regimens was instituted prior to the licencing of obeticholic acid in Canada, and therefore, other second line therapies were not employed. Written informed consent was obtained from each patient, and their management was discussed by all members of the Liver Transplant committee prior to starting therapy.

1.2 Case 1

At the age of 15, the female patient was diagnosed with PBC by liver biopsy, an AMA titer of 1:800 and cholestatic liver tests, and then was commenced on UDCA. She reported sensory neuropathy in a glove-and-stocking distribution and was subsequently diagnosed with rheumatoid arthritis and Sjogren's disease. Three years later, her mother required LT as a result of end-stage PBC and then the proband required LT at the age of 21. The initial immunosuppression regimen included mycophenolate mofetil (MMF) and tacrolimus, which was reduced to tacrolimus monotherapy for the second year as her liver tests stabilised. A flare in her liver enzymes occurred 2 years following LT, and the liver histology (biopsy 1) confirmed rPBC with mild cholangitis and F1 fibrosis (Figure 1). On reintroduction of UDCA and restarting the MMF 500-mg BID, her ALP level returned to near baseline by year 3. But the cholestatic liver disease worsened considerably, and into year 5 she developed abnormal bilirubin with histological evidence of cholangitis and ductopenia (biopsy 3). The tacrolimus immunosuppression was changed to cyclosporin A in an effort to improve the rPBC, but cyclosporin A was not tolerated and the tacrolimus was restarted.

At year 7 following LT, the patient developed EBV DNA in peripheral blood (10⁵-10⁵ copies/ug DNA), which was initially managed with valganciclovir and decreased dosing of immunosuppression. A diagnosis of posttransplant lymphoproliferative disorder (PTLD) was established by bone marrow biopsy showing a diffuse aggressive large B cell lymphoma. The MMF was discontinued, and methotrexate, Ara-C, hydrocortisone and Rituximab treatment was instituted that led to undetectable EBV DNA levels within the month. However, the biochemical disease had progressed significantly, and the liver biopsy (biopsy 7) revealed evidence of progressive ductopenia and bridging fibrosis.

Following discussion with the patient and the liver transplant committee, the patient was commenced on daily FTC/TDF 200/300 mg and LPRr 800/200 mg. Maintaining stable tacrolimus levels became challenging as a result of LPRr blocking CYP450 3A activity. Eventually, a dose of 0.5-mg tacrolimus per week resulted in achievement of therapeutic levels. Within the first month of combination ART, she experienced a biochemical hepatitis consistent with LPRr toxicity.⁹ Although serum aminotransferases remained elevated, the ALP levels had fallen by >350 U/L and bilirubin by 4 μmol/ml by the end of the first month, and the combination ART was continued. In the ensuing years, her bilirubin and AST stabilised close to the ULN and the ALP subsided and normalised on one occasion. The serial HBRV DNA was measured by digital droplet PCR in whole blood DNA with the initiation of therapy.⁹ The viral load was initially positive and subsequently became negative with one borderline measurement (Figure 1).

To determine the efficacy of combination ART, coded liver biopsies were assessed using the cholangitis, hepatitis, ductopenia and fibrosis parameters from the Nakanuma scoring system.¹⁶ After 3 years of antiviral therapy, there was a reduction in fibrosis and the cholangitis score remained at baseline in all the biopsies derived whist on ART (biopsies 8-11). However, 4 years after commencing antiviral treatment (year 12), the patient found it difficult to swallow large tablets (LPRr and UDCA) because of the sensory neuropathy. Smaller UDCA and LPRr tablets were provided, but she subsequently discontinued all combination ART, which resulted in a degree of rebound in her hepatic biochemistry.

1.3 Case 2

A 45-year-old female, First Nations patient presented with a 3-year history of intermittent right upper quadrant pain, early satiety, weight loss and abnormal cholestatic liver tests. The family history revealed that her mother died aged 60 with cirrhosis and jaundice. A laparoscopic cholecystectomy was performed for chronic cholecystitis related to cholelithiasis, and a wedge liver biopsy revealed PBC with ductopenia and bridging fibrosis. The serology revealed a weakly positive antismooth muscle antibody 1:50, negative AMA and ANA and markedly raised serum IgM of 11.7 g/L. Despite UDCA treatment, her clinical disease rapidly progressed over the next 6 years and she subsequently became AMA positive. A LT was performed with a split-liver allograft at the age of 51.

MMF and tacrolimus were initially used for immunosuppression, but the latter was changed to sirolimus due to delirium in the postoperative period. Four months after LT, the patient developed increased ALP and the liver biopsy revealed evidence of cholangitis with a rejection activity index score of 4/9 (biopsy 1). The sirolimus was changed to cyclosporin A with MMF, and ursodiol was commenced. Her liver biochemistry improved but failed to normalise, and a second biopsy performed at 2 years was consistent with rPBC. Her low dose MMF was discontinued at this point. Following a rise in her AST and ALP three and a half years after LT, a third liver biopsy was obtained, which revealed moderate interface hepatitis accompanying the rPBC (biopsy 3). Her immunoglobulin IgG levels were within normal limits 12 g/L, whereas her IgM was elevated at 9.0 g/L. A decision was made to treat her with 40-mg prednisone, and the patient's liver tests subsequently normalised with a very slow taper and the institution of azathioprine as a steroid sparing agent.

After discontinuing the prednisone, she developed rebound biochemical hepatitis. Her azathioprine was also discontinued because of neutropenia. The liver biopsy showed histological features consistent with rPBC with focal lymphocytic cholangitis and moderate interface activity (biopsy 4).

Following discussion with the patient and the liver transplant committee, a decision was made to commence combination ART. By then, we had established that RAL had an EC95 in the nM range against HBRV suitable for inhibition at doses used for HIV, whereas LPRr was associated with GI intolerance.⁹ As the patient already suffered from chronic kidney injury, the combination ART treatment was commenced with RAL and Tenofovir alafenamide (TAF)/FTC instead of than TDF/FTC. After 1 year, her ALP, AST and bilirubin had returned to normal values. A liver biopsy to monitor the combination ART showed reduction in the severity of interface hepatitis and curtailment of cholangitis (biopsy 5). A year later, she was admitted to hospital with confusion and acute on chronic kidney injury. A biopsy was performed to monitor therapy (biopsy 6), which showed increased inflammation with deterioration of the hepatitis and cholangitis scores. The combination ART was discontinued, and she developed a biochemical rebound with increased ALP, AST and bilirubin.