Evolution of Liver Transplantation Indications: Expanding Horizons

Chronic Hepatitis B in the Transplant Setting: A 30-Year Experience in a Single Tertiary Italian Center

BACKGROUND

Hepatitis B virus (HBV) remains a leading etiology for liver transplantation (LT). In a large cohort of HBsAg-positive patients, this study evaluates long-term patient and graft survival after LT over the past 30 years while analyzing trends and outcomes following waiting list (WL) inclusion over the last 15 years.

METHODS

HBsAg-positive patients who underwent transplantation between 1991 and 2020 and were waitlisted from 2006 to 2020 at Padua Hospital were included in the analysis. Patients were stratified according to hepatitis delta virus (HDV) coinfection, transplant indication (decompensated cirrhosis vs. hepatocellular carcinoma (HCC)), and WL inclusion period.

RESULTS

Among 321 HBsAg-positive LT recipients (31.5% HDV-coinfected, 46.4% HCC), 1-year and 5-year patient/graft survival rates were 87.6%/86.7% and 82.6%/82.2%, respectively. From 2006 to 2020, 284 HBsAg-positive patients were waitlisted (32.6% HDV-coinfected), with a significantly higher prevalence of HCC compared to non-HBV patients (p = 0.008). High-barrier nucleos(t)ide analogues (hbNUCs) significantly reduced mortality (p = 0.041) and improved survival post-WL inclusion (p = 0.007). Survival rates were consistent regardless of LT indication, HDV coinfection, or WL inclusion period. Post-transplant prophylaxis predominantly involved immunoglobulins (HBIG) + NUCs, resulting in only two cases of HBV reactivation, both clinically inconsequential.

CONCLUSIONS

Over the past 30 years, HBV has remained a consistent indication for LT at our center. Thanks to hbNUCs, WL outcomes have improved and HCC has become the main indication for LT.

The role of living donor liver transplantation in colorectal cancer liver metastases

PURPOSE OF REVIEW

Despite technical and therapeutic advances, only 20-40% of patients with colorectal liver metastases (CRLM) have resectable disease. Historically, the remaining patients with unresectable, liver-only CRLM would receive palliative chemotherapy, with a median survival of 8 months.

RECENT FINDINGS

Liver transplantation has emerged as a viable option for selected patients with CRLM. This advancement stems from improved understanding of tumour genomics and biology and better patient selection criteria. The results of recent prospective clinical trials have further ignited enthusiasm for liver transplantation as a viable therapeutic option. Living donor liver transplantation (LDLT) offers several advantages over deceased donor liver transplantation (DDLT) for this disease, including reduced wait-time and optimized timing and coordination of oncologic therapy. On-going LDLT clinical trials have demonstrated favourable outcomes as compared with other liver transplantation indications. However, there is no established consensus or standardization in the implementation of LDLT for CRLM, beyond trials and centre-specific protocols.

SUMMARY

LDLT is an excellent therapeutic option in highly selected patients with CRLM. Refining prognostic factors and selection criteria will help to further optimize the utility and broaden the acceptance and implementation of LDLT for patients with CRLM.

Liver transplantation plus chemotherapy versus chemotherapy alone in patients with permanently unresectable colorectal liver metastases (TransMet): results from a multicentre, open-label, prospective, randomised controlled trial

BACKGROUND

Despite the increasing efficacy of chemotherapy, permanently unresectable colorectal liver metastases are associated with poor long-term survival. We aimed to assess whether liver transplantation plus chemotherapy could improve overall survival.

METHODS

TransMet was a multicentre, open-label, prospective, randomised controlled trial done in 20 tertiary centres in Europe. Patients aged 18-65 years, with Eastern Cooperative Oncology Group performance score 0-1, permanently unresectable colorectal liver metastases from resected BRAF-non-mutated colorectal cancer responsive to systemic chemotherapy (≥3 months, ≤3 lines), and no extrahepatic disease, were eligible for enrolment. Patients were randomised (1:1) to liver transplantation plus chemotherapy or chemotherapy alone, using block randomisation. The liver transplantation plus chemotherapy group underwent liver transplantation for 2 months or less after the last chemotherapy cycle. At randomisation, the liver transplantation plus chemotherapy group received a median of 21·0 chemotherapy cycles (IQR 18·0-29·0) versus 17·0 cycles (12·0-24·0) in the chemotherapy alone group, in up to three lines of chemotherapy. During first-line chemotherapy, 64 (68%) of 94 patients had received doublet chemotherapy and 30 (32%) of 94 patients had received triplet regimens; 76 (80%) of 94 patients had targeted therapy. Transplanted patients received tailored immunosuppression (methylprednisolone 10 mg/kg intravenously on day 0; tacrolimus 0·1 mg/kg via gastric tube on day 0, 6-10 ng/mL days 1-14; mycophenolate mofetil 10 mg/kg intravenously day 0 to <2 months and switch to everolimus 5-8 ng/mL), and postoperative chemotherapy, and the chemotherapy group had continued chemotherapy. The primary endpoint was 5-year overall survival analysed in the intention to treat and per-protocol population. Safety events were assessed in the as-treated population. The study is registered with ClinicalTrials.gov (NCT02597348), and accrual is complete.

FINDINGS

Between Feb 18, 2016, and July 5, 2021, 94 patients were randomly assigned and included in the intention-to-treat population, with 47 in the liver transplantation plus chemotherapy group and 47 in the chemotherapy alone group. 11 patients in the liver transplantation plus chemotherapy group and nine patients in the chemotherapy alone group did not receive the assigned treatment; 36 patients and 38 patients in each group, respectively, were included in the per-protocol analysis. Patients had a median age of 54·0 years (IQR 47·0-59·0), and 55 (59%) of 94 patients were male and 39 (41%) were female. Median follow-up was 59·3 months (IQR 42·4-60·2). In the intention-to-treat population, 5-year overall survival was 56·6% (95% CI 43·2-74·1) for liver transplantation plus chemotherapy and 12·6% (5·2-30·1) for chemotherapy alone (HR 0·37 [95% CI 0·21-0·65]; p=0·0003) and 73·3% (95% CI 59·6-90·0) and 9·3% (3·2-26·8), respectively, for the per-protocol population. Serious adverse events occurred in 32 (80%) of 40 patients who underwent liver transplantation (from either group), and 69 serious adverse events were observed in 45 (83%) of 54 patients treated with chemotherapy alone. Three patients in the liver transplantation plus chemotherapy group were retransplanted, one of whom died postoperatively of multi-organ failure.

INTERPRETATION

In selected patients with permanently unresectable colorectal liver metastases, liver transplantation plus chemotherapy with organ allocation priority significantly improved survival versus chemotherapy alone. These results support the validation of liver transplantation as a new standard option for patients with permanently unresectable liver-only metastases.

FUNDING

French National Cancer Institute and Assistance Publique-Hôpitaux de Paris.

Comparison of wild-type and high-risk PNPLA3 variants in a human biomimetic liver microphysiology system for metabolic dysfunction-associated steatotic liver disease precision therapy

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a worldwide health epidemic with a global occurrence of approximately 30%. The pathogenesis of MASLD is a complex, multisystem disorder driven by multiple factors, including genetics, lifestyle, and the environment. Patient heterogeneity presents challenges in developing MASLD therapeutics, creating patient cohorts for clinical trials, and optimizing therapeutic strategies for specific patient cohorts. Implementing pre-clinical experimental models for drug development creates a significant challenge as simple in vitro systems and animal models do not fully recapitulate critical steps in the pathogenesis and the complexity of MASLD progression. To address this, we implemented a precision medicine strategy that couples the use of our liver acinus microphysiology system (LAMPS) constructed with patient-derived primary cells. We investigated the MASLD-associated genetic variant patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 (I148M variant) in primary hepatocytes as it is associated with MASLD progression. We constructed the LAMPS with genotyped wild-type and variant PNPLA3 hepatocytes, together with key non-parenchymal cells, and quantified the reproducibility of the model. We altered media components to mimic blood chemistries, including insulin, glucose, free fatty acids, and immune-activating molecules to reflect normal fasting (NF), early metabolic syndrome (EMS), and late metabolic syndrome (LMS) conditions. Finally, we investigated the response to treatment with resmetirom, an approved drug for metabolic syndrome-associated steatohepatitis (MASH), the progressive form of MASLD. This study, using primary cells, serves as a benchmark for studies using "patient biomimetic twins" constructed with patient induced pluripotent stem cell (iPSC)-derived liver cells using a panel of reproducible metrics. We observed increased steatosis, immune activation, stellate cell activation, and secretion of pro-fibrotic markers in the PNPLA3 GG variant compared to the wild-type CC LAMPS, consistent with the clinical characterization of this variant. We also observed greater resmetirom efficacy in the PNPLA3 wild-type CC LAMPS compared to the GG variant in multiple MASLD metrics, including steatosis, stellate cell activation, and the secretion of pro-fibrotic markers. In conclusion, our study demonstrates the capability of the LAMPS platform for the development of MASLD precision therapeutics, enrichment of patient cohorts for clinical trials, and optimization of therapeutic strategies for patient subgroups with different clinical traits and disease stages.

Serum Cytokeratin-18 levels as a prognostic biomarker in advanced liver disease: a comprehensive meta-analysis

Cytokeratin-18 (CK-18) is a marker of hepatic cell death. Serum CK-18 could serve as a prognostic marker for patients with advanced liver disease (ALD). This meta-analysis aims to explore the association between total CK-18 (M65) and caspase-cleaved CK-18 (M30) levels with the prognosis of ALD patients. Relevant longitudinal observational studies were identified through comprehensive searches of the Medline, Web of Science, and Embase databases. A random-effects model was utilized to synthesize the findings, accommodating heterogeneity among studies. The analysis included 14 datasets from 11 studies. Elevated serum CK-18 levels at admission were linked to a higher risk of death or liver transplantation during follow-up. This association was consistent for both M65 (risk ratio [RR] 1.99, 95% confidence interval [CI] 1.65 to 2.40, p < 0.001; I2 = 43%) and M30 (RR 1.94, 95% CI 1.57 to 2.40, p < 0.001; I2 = 46%). Subgroup analysis revealed that the relationship between serum M65 levels and adverse outcomes was attenuated in studies using multivariate analysis compared to those using univariate analysis (RR 1.78 vs. 2.80, p for subgroup difference = 0.03). Further subgroup analyses indicated that the prognostic significance of CK-18 for ALD patients was not significantly influenced by study design, methods of determining CK-18 cutoff values, or follow-up durations. Elevated serum CK-18 levels at admission indicate a poor prognosis in patients with ALD. This finding holds for both M65 and M30.

Comparison of Wild-Type and High-risk PNPLA3 variants in a Human Biomimetic Liver Microphysiology System for Metabolic Dysfunction-associated Steatotic Liver Disease Precision Therapy

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a worldwide health epidemic with a global occurrence of approximately 30%. The pathogenesis of MASLD is a complex, multisystem disorder driven by multiple factors including genetics, lifestyle, and the environment. Patient heterogeneity presents challenges for developing MASLD therapeutics, creation of patient cohorts for clinical trials and optimization of therapeutic strategies for specific patient cohorts. Implementing pre-clinical experimental models for drug development creates a significant challenge as simple in vitro systems and animal models do not fully recapitulate critical steps in the pathogenesis and the complexity of MASLD progression. To address this, we implemented a precision medicine strategy that couples the use of our liver acinus microphysiology system (LAMPS) constructed with patient-derived primary cells. We investigated the MASLD-associated genetic variant PNPLA3 rs738409 (I148M variant) in primary hepatocytes, as it is associated with MASLD progression. We constructed LAMPS with genotyped wild type and variant PNPLA3 hepatocytes together with key non-parenchymal cells and quantified the reproducibility of the model. We altered media components to mimic blood chemistries, including insulin, glucose, free fatty acids, and immune activating molecules to reflect normal fasting (NF), early metabolic syndrome (EMS) and late metabolic syndrome (LMS) conditions. Finally, we investigated the response to treatment with resmetirom, an approved drug for metabolic syndrome-associated steatohepatitis (MASH), the progressive form of MASLD. This study using primary cells serves as a benchmark for studies using patient biomimetic twins constructed with patient iPSC-derived liver cells using a panel of reproducible metrics. We observed increased steatosis, immune activation, stellate cell activation and secretion of pro-fibrotic markers in the PNPLA3 GG variant compared to wild type CC LAMPS, consistent with the clinical characterization of this variant. We also observed greater resmetirom efficacy in PNPLA3 wild type CC LAMPS compared to the GG variant in multiple MASLD metrics including steatosis, stellate cell activation and the secretion of pro-fibrotic markers. In conclusion, our study demonstrates the capability of the LAMPS platform for the development of MASLD precision therapeutics, enrichment of patient cohorts for clinical trials, and optimization of therapeutic strategies for patient subgroups with different clinical traits and disease stages.