Post liver transplant immunosuppression

Shankar Zanwar

First successful organ transplant

Liver transplant • First human liver transplant – 1963 – Dr Thomas Starlz Colorado – Canada

• First 1 year survival – 1967

• Introduction of Calcineurin inhibitors in liver Tx

• First successful liver transplant in India – 1998

Liver – distinction in transplants• A huge load of antigens exposed to liver – pathogens, toxins tumor cells dietary and non dietary proteins

• Compared with other organ transplants• Immunologically privileged• Rarity of hyper-acute rejection despite positive T cell

cross match• Low incidence of graft loss due to chronic rejection• Potential of regeneration of liver cells after tissue

injury

Immunological basis of rejection -

1. Alloantigen recognition – • The graft antigen is

recognized as foreign by antigen presenting cells

• This recognition as foreign is presented to the T -lymphocytes along with major histocompatibility complex

• The antigen from MHC binds T-cells receptors

2. Lymphocyte activation – co-stimulation

• T cell activation – needs co-stimulation

• Ligands on APC binds to receptors on T cells – CD28, CD154, CD2, CD11a & CD54

• Receptor ligand complex activates immunophilin stimulates calcineurin nuclear factor of T cells IL-2 transcription.

3.Clonal expansion•Newly synthesized IL-2 by T cells binds to IL-2 receptors on the cells surface

• Stimulates T-cells in autocrine manner cell proliferation

• Finally this T- cell proliferation cell mediated cytotoxicity and secretion of cytokines, chemokines that attracts other attacker cells.

• Result in inflammatory environment and graft cell death.

Acute rejection•Occurs in 10-70% of patients depending on primary immunosuppression used, indication of transplant and definition of rejection

Neuberger J Hepatology 1998

• Early acute rejection –within 90 days• Late acute rejection after more than 180 days• Clinical presentation• Fever• Malaise • Abdominal pain , H/S megaly and rarely splenomegaly

Criteria• Clinical – in absence of no other obvious causes• Increase in ALT >50 U/l• And or Bilirubin > 6 mg/dl• Changes reversed by antirejection therapy

Schlitt, Transplantation 1992

•Despite many biomarkers (microRNAs), histology is gold standard, 3 classic findings• Mixed inflammatory infiltrate in portal triad• Nonsuppurative cholangitis • Endothelitis

Banff grading of ACR• Mild – Inflammatory infiltrate in the portal triad and around the bile duct limited to a minority of the triads/ducts - 1

• Moderate – Infiltrate involving most or all of the triads/ducts -2

• Severe – Spill over in the periportal areas, mod-sev endothelitis, perivenular extension and necrosis of hepatocytes – 3

Demetris et al Hepatology 1997

• Rejection activity index(RAI) - <4 Mild

• Though indicator of severity, RAI doesn't correlate steroid response or graft survival

Horolodt Liver transplant 2006

•Differential diagnosis of ACR• Recurrent HCV infection• Functional cholestasis – subcellular organelle damage

– cold ischemia time• Cyclosporine toxicity – ↑LFT a/w unexplained ↑ creat• Massive hemorrhagic necrosis - rare

Pharmacotherapy of immunosuppression•Drug classes• Signal I - Alloantigen recognition – Antilymphocyte/thymocyte

antibodies

• Signal II- Lymphocyte co-stimulation – inhibits signal transduction – Calcineurin inhibitors – Cyclosporine and Tacrolimus

• Signal III- Clonal expansion – IL-2R blockers – Basiliximab/Sirolimus

• DNA synthesis inhibitors – Mycophenolate and azathioprine

• Steroids

Antibodies – Induction therapy• Polyclonal antibodies – Thymoglobulin used commonly

•Use – induction or steroid resistant rejection

• 1st dose is given in intra-op – anhepatic phase

•May lead to cytokine release(flu like) syndrome, leucopenia and thrombocytopenia

• In metaanalysis of 19 trials – reduces acute rejection when compared to placebo, RR 0.85

• But overall no difference in mortality, graft loss or mortality

Penniga L, Ab induction vs placebo Cochrane Datab sys rev, 2014

Steroids•Glucocorticoids • suppress antibody and complement binding,• Upregulate IL-10 (anti-inflammatory)• Downregulate IL-2 and IL-6 (proinflammatory)• IFN-Y synthesis inhibition

• Commonly used steroids• Hydrocortisone• Prednisolone• Prednisone• Methylprednisolone

Baylor college steroid protocol

•No agreement on protocol amongst different centers

• Tapering to zero is usually is achieved over 3-6months but most centers leave 5mg/d indefinitely

• Side effects - known to all

• Budesonide – a possible alternative, reduced systemic effects d/t high first pass

•One study has used this with apparent success in post LTx pts. with significant success – further RCTs required

Bhat M Liver transplant 2012

HCV and glucocorticoids• Steroid ↑ HCV replication in post LTx HCV infection

• 3 options • Maintain low dose steroid 5mg/d indefinitely• Taper slowly• Avoid steroids

•Majority use slow tapering

• Rapid tapering ↑ chance of fibrosisVivarelli J Hepatology 2007

• Steroid free regimen can be tried – Multiple options available

• Latest trial – of 75 pts. compared tac + steroid with tac + Mycophenolate – Event free survival at 1 and 5 year similar in both group.

Takada, Liver Tx, 2013

• Caution – aggressive immunosuppression - late consequences as post Tx lymphoproliferative dis.

Calcineurin inhibitors

Cyclosporine• Administration – IV, oral tabs or suspension

• Peak blood levels in 2-4 hours

• Avg t ½ - 15 hours

• Cleared from bile, hepatic metabolism – CYP3A4

•Dosing • initially - 8-10mg/kg/d,• maintenance – 2-6mg/kg/d

• Initially daily monitoring with reducing frequency after graft function stabilization

•Multiple drugs interact with cyclosporine.

• Target level initial 3 mons 200-250ng/ml, tapered down to 12 months to 80-120ng/ml

•Microemulsion fromulations better – ↑ bioavailability, faster acting and less variability

Tacrolimus•Macrolide isolated from Streptomyces

• Inhibits IL-2 and IFN-Y production, 100X more potent than cyclosporine

•Metabolized in liver same enzyme as Cyclo

•Not removed by dialysis

• Tacrolimus dosing should be individualized – to start with 0.5 to 1mg 12 hours on POD 1

• Aim target of 7-10ng/dl by end of 1 week

• A level 6ng/ml is satisfactory at 6 mons and 4-6ng/ml beyond 1 year

• Slightly higher levels are better for autoimmune, PBC and PSC

• Lower doses are appropriate alcohol and hemochromatosis.

OD tacrolimus•Many studies now recommend prolonged release Tacrolimus over the twice daily regime

• Trial • n= 34 pt switched from BD to OD regimen• Median conversion period median 38 (range 8-211)• No difference in the mean trough levels• Renal function – GFR increased in OD dosing regimen

67ml/min vs 73ml/min mean p=0.003Valente G Transplant 2013

•OD dosing in stable pts. improves quality of care and renal function and adherence to immunosupp.

S/e of calcineurin inhibitors• Hepatotoxicity• Cardiovascular• HTN(C>T)• Hypercholesterolemia

• Glucose intolerance(T>C)• Neurotoxicity(T>C)• Tremors, myoclonus• Headache, seizures• Insomnia, hallucinations• Paresthesia • Dysarthria,

polyneuropathy

• Nephrotoxicity• Striped fibrosis• HyperK, hypomag.• Type IV RTA

• Cosmetic • Gingival hypertrophy(C>T)• Hirsutism(C>T)• Alopecia(T>C)

•Malignancy • Skin cancers• Cervical cancers• Lymphoproliferative

disorders• GI upset(T>C)

Interactions with other drugs• That ↑ levels• CCBs• Azole antifungals• Sirolumus• Methyl prednisolone• Macrolide antibiotics• Protease inhibitors

(ART)• Grape juice

• That ↓ levels• ATT (INH and Rif)• Anticonvulsants – older• Imipenem• Ciproflox• Cephalosporin• Ticlopedine

Cyclosporine Vs Tacrolimus • Landmark study – O’ Grady – Lancet 2002• RCT with 606 pts.

• All results statistically significant• All results studied at end 1 year• Tacrolimus scores more!

Outcomes Microem Cyclosporine TacrolimusDeath 32% 21%MODS 10% 10%Treatment failure 4% 2%Renal dysfunction and need for antihypertensive equal in both group

• Another metaanalysis of 16 trials – treating 100pts with tac vs cyclo would avoid rejection in 9 pt and death in 2 but would create 4 extra diabete

McAlister Am J Transplant 2006

Sirolimus

Sirolimus•Macrolide antibiotic from Streptomyces

•Works synergistically with Tacrolimus

•May be useful as substitute in CNI intoleranceBeckebaum Clin Transpl 2004, Watson CJ Liver transplant 2007

•Dosing • 2-5 mg once daiy• Level should be maintained at 5-15ng/ml

• S/e - Similar to CNI, may also have pancytopenia, interstitial pneumonia, Hep AT, delayed healing

• Benefits in renal failure are not clear

• Some initial improvement in GFR but may not sustain in long term

DuBay Liver transplant 2008

•May be of benefit in patients with HCC – since antiproliferative action

Zimmerman Liver transplant 2008

• Because of many side effects FDA warning – do not use in de-novo in liver transplant recipients

Stamp release on first successful liver transplant survivor in India

Everolimus•Hydroxyethyl derivative of sirolimus

• Starting dose 0.75mg BD, levels at 3-8ng/dl maintenance

• In a study with 3 groups, n= 719(after 1 month tac post LTx)• Everolimus with tac elimination (EVR)• Everolimus + low dose Tacrolimus (EVR + TAC)• Standard dose TAC

De Simone Am J Trans 2012

• Everlolimus facilitates early Tacrolimus minimization, with comparable efficacy and superior renal function compared with std. tac regimen at 1 year

DNA synthesis inhibitors

Mycophenolate• Derrived from penicillium

• Oral dose but poor absorption

• Inhibits enzyme for guanine nucleotide formation inhibit DNA synthesis

• Lymphocyte lack a salvage pathway of guanine nucleotide formation succumb

• Usual dose 1gm BD (Myfortic 720mg), level to be maintained – 1.6-2.75mg/dl

• S/e – Pancytopenia and GI upset

• Role of MMF is similar to siroliminus i.e. reduce or discontinue CNI dosing to treat side effects

• In a RCT with 150pts., CNI vs MMF(alone) 5 year follow-up• No significant difference in ACR, higher rejection freq. in

MMF• No significant difference CVS, GI and CNS S/e• Renal functions improved significantly when switched to

MMF from CNI Schmeding, Transplantation 2011

• Azathioprine vs MMF almost similar except for expenses (MMF costlier),but AZA less studied in LTx

Antibody therapy• Monoclonal antibodies• Muromonab –CD3(OKT3) – 1st MAB approved for transplant

• Blocks cytotoxic t cells in graft

• Standard dose 5mg IV daily for 10-14 days

• Initital few doses flu like syndrome – managed with hydrocort, avil and PCM

• Successful OKT3 treatment – rapid decline in CCD3+ T cells – from 60 5%

• Long term side effect Lymphoproliferative disease – 3%HC Devarbhavi Am J Transplant 2006

•Muromonab – • Main utility is for steroid resistant rejection• Trial - steroid resistant rejection

• n=28, steroid continuation vs OKT3, with cross over if failed• Steroid group - 3/13 responded, 10 switched to OKT

• 9/10 switched responded with median improvement for 8months• OKT group 11/15 responded, 2 rescued by steroid 1 retransplant,

1 death• OKT3 is superior to higher dose steroids in reversing

allograft rejection in failed steroid therapyCosimi AB Transplantation 1987

Other MABs

Other MABs• Basiliximab and daclizumab –• Humanized MABs block IL-2 receptors

• Less immunogenic than OKT3(though not relevant here)

• Longer T ½ and better tolerated

• Similar efficacy for both agents

• Dosing –• Basiliximab 20mg IV preop and POD4• Daclizumab 1mg/kg preop and every week X 6 doses

•Main role of these is for renal sparing induction regimen

• Abs can reduce CNI use in pts. with preOLT renal disesase

• These may also be used in to minimize steroid use

• Trial - RCT • Tac + steroid (n=347) vs Tac + daclizumab (n=351)• Steroid resistant ACR incidence 6 vs 3• Adverse events were similar

Boillot Liver Transplant 2005

• But these agents can’t be used as for treating rejection

Experimental Agents• Belatacept – CD80/86 binder – • Proven beneficial in renal transplant• Increased rate of PTLPD• Clear data in liver transplant are awaited

• Efalizumab – CD11a inhibitor• Stabilizes APC-T cell complex• One trial has shown benefit• More data needed to prove efficacy

• Alemtuzumab – anti CD52 • In LTx it has been used as agent to reduce CNI/steroid use• Infectious complications are prominent

Balancing act – immunosuppression in renal impairment

Renal sparing regimens• Significant renal dysfunction – 40% of LTx,

• AKI occurs in 15% post op cases, worsens mid or long term survival

• CNI cause dose related and reversible ↓ in GFR

• CNI induced nephrotoxicity caused by intense arteriolar vasoconstrictions prerenal dysfunction

• Chronic renal dysfunction impacts long term survivalDuvoux, J of Hepatology 2011

Approach in early post op period

Duvoux, J of Hepatology 2011

Mid & long term renal protection

Duvoux, J of Hepatology 2011

Immunosuppression in post transplant HCV• Steroids and Antilymphocyte therapies are a/w severe HCV recurrence

• Tacrolimus and cyclosporine similar in recurrence, but graft and pt. survival better with Tacrolimus

• Benefits from low dose and slow tapering of steroids and long term azathioprine are seen

• Rapid changes in regimens may be deleterious

•Weaning off the immunosuppression is appealing but not yet practical.

Dimitrios J of Hepatology 2012

Immunosuppression - HCC• Recurrence rates post transplant 3.5-21%

• CNI may pose risk of recurrence

• Cyclosporine better than Tacrolimus – lesser risk

• CNI and mTtor regimen better since sirolimus has anti tumor activity due to anti VEGF action

•Metaanalysis substantiates role if sirolimus contain regimen

Liang W Liver transplant 2012

Neuberger, Clinical and experimental Immunology 2005

Immunosuppression for surgical candidates• Continue ongoing medications, route may be changed

• IV administration of CNI is more cytotoxic avoid if possible

• Check drug interactions

• IV steroids as an addition in routine dose in steroid based regimen since they are likely to have hypothalamo-pituitary axis

Stopping immunosuppression • Some pts develop tolerance and may be able to stop immunosuppression

• In a study discontinuation was tried in 24 pts.,• 63% were tolerant at 14 moths(median)• Remaining had acute or chronic rejections

Srobe Liver transplant 2013

• Complete weaning – still a far fetched dream

Thank You