Immune-mediated Hepatotoxicity Research Articles

Risk Factors of Immune-Mediated Hepatotoxicity Induced by Immune Checkpoint Inhibitors in Cancer Patients: A Systematic Review and Meta-Analysis

Immune checkpoint inhibitors (ICIs) significantly improve survival, while immune-mediated hepatotoxicity (IMH) has been reported. To evaluate the incidence and potential risk factors of IMH among cancer patients treated by ICIs, PubMed/Medline, Web of Science, Cochrane, and Embase were searched before 30 March 2024 for systematic review and meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CI) were calculated. Quality assessment was completed using the Newcastle–Ottawa scale. Of 1217 articles identified, 24 consisting of 9076 patients were included, with one study being prospective and the rest retrospective. The overall incidence of any grade IMH and grade ≥ 3 secondary to ICIs was 14% and 7%, respectively. The cholestatic pattern was more prevalent than the hepatocellular and mixed patterns. The meta-analysis revealed that ICI treatment was related to reduced risk of IMH in older patients (SMD: −0.18; 95% CI: −0.33 to −0.04), individuals with higher body mass index (WMD: −2.15; 95% CI: −3.92 to −0.38), males (OR: 0.44; 95% CI: 0.27 to 0.72), and patients with lung cancer (OR: 0.58, 95%CI 0.41 to 0.83). On the other hand, patients with liver metastasis (OR: 1.80; 95% CI: 1.47 to 2.20), history of ICI treatment (OR: 3.09; 95% CI: 1.21 to 7.89), diabetes (OR: 2.19; 95% CI: 1.36 to 3.51), chronic HBV (OR: 3.06; 95% CI: 1.11 to 8.46), and concomitant use of ICIs (OR: 8.73; 95% CI: 2.41 to 31.59) increased the risk of developing IMH. This study will provide clinicians with information on potentially high-risk groups for IMH, who need to be cautiously monitored for liver function when receiving immunotherapy.

Opportunities for Microphysiological Systems in Toxicity Testing of New Drug Modalities.

New drug modalities offer life-saving benefits for patients through access to previously undruggable targets. Yet these modalities pose a challenge for the pharmaceutical industry, as side effects are complex, unpredictable, and often uniquely human. With animal studies having limited predictive value due to translatability challenges, the pharmaceutical industry seeks out new approach methodologies. Microphysiological systems (MPS) offer important features that enable complex toxicological processes to be modeled in vitro such as (a) an adjustable complexity of cellular components, including immune components; (b) a modifiable tissue architecture; (c) integration and monitoring of dynamic mechanisms; and (d) a multiorgan connection. Here we review MPS studies in the context of four clinical adverse events triggered by new drug modalities: peripheral neuropathy, thrombocytopenia, immune-mediated hepatotoxicity, and cytokine release syndrome. We conclude that while the use of MPS for testing new drug modality-induced toxicities is still in its infancy, we see strong potential going forward.

The ABC of Immune-Mediated Hepatitis during Immunotherapy in Patients with Cancer: From Pathogenesis to Multidisciplinary Management.

Immune-mediated hepatotoxicity (IMH) is not-so-rare complication during treatment with immune checkpoint inhibitors (ICIs). This narrative review aims to report the current knowledge on hepatic immune-related adverse events (irAEs) during immunotherapy from pathogenesis to multidisciplinary management. The majority of cases of IMH are asymptomatic and only a few patients may have clinical conditions. The severity of IMH is usually stratified according to Common Terminology for Clinical Adverse Events (CTCAE) criteria, but these scores may overestimate the clinical severity of IMH compared to the Drug-Induced Liver Injury Network (DILIN) scale. The differential diagnosis of IMH is challenging because the elevated liver enzymes can be due to a number of etiologies such as viral infection, autoimmune and metabolic diseases, liver metastases, biliary diseases, and other drugs. The cornerstones of IMH management are represented by withholding or delaying ICI administration and starting immunosuppressive therapy. A multidisciplinary team, including oncologists, hepatologists, internists, and emergency medicine physicians, is essential for the management of IMH.

Immuno-inflammatory in vitro hepatotoxicity models to assess side effects of biologicals exemplified by aldesleukin.

Hepatotoxicity induced by immunotherapeutics is an appearing cause for immune-mediated drug-induced liver injury. Such immuno-toxic mechanisms are difficult to assess using current preclinical models and the incidence is too low to detect in clinical trials. As hepatotoxicity is a frequent reason for post-authorisation drug withdrawal, there is an urgent need for immuno-inflammatory in vitro models to assess the hepatotoxic potential of immuno-modulatory drug candidates. We developed several immuno-inflammatory hepatotoxicity test systems based on recombinant human interleukin-2 (aldesleukin). Co-culture models of primary human CD8+ T cells or NK cells with the hepatocyte cell line HepaRG were established and validated with primary human hepatocytes (PHHs). Subsequently, the HepaRG model was refined by increasing complexity by inclusion of monocyte-derived macrophages (MdMs). The main readouts were cytotoxicity, inflammatory mediator release, surface marker expression and specific hepatocyte functions. We identified CD8+ T cells as possible mediators of aldesleukin-mediated hepatotoxicity, with MdMs being implicated in increased aldesleukin-induced inflammatory effects. In co-cultures of CD8+ T cells with MdMs and HepaRG cells, cytotoxicity was induced at intermediate/high aldesleukin concentrations and perforin was upregulated. A pro-inflammatory milieu was created measured by interleukin-6 (IL-6), c-reactive protein (CRP), interferon gamma (IFN-γ), and monocyte chemoattractant protein-1 (MCP-1) increase. NK cells responded to aldesleukin, however, only minor aldesleukin-induced cytotoxic effects were measured in co-cultures. Results obtained with HepaRG cells and with PHHs were comparable, especially regarding cytotoxicity, but high inter-donor variations limited meaningfulness of the PHH model. The in vitro test systems developed contribute to the understanding of potential key mechanisms in aldesleukin-mediated hepatotoxicity. In addition, they may aid assessment of immune-mediated hepatotoxicity during the development of novel immunotherapeutics.

Brief Report: Severe Sotorasib-Related Hepatotoxicity and Non-Liver Adverse Events Associated With Sequential Anti–Programmed Cell Death (Ligand)1 and Sotorasib Therapy in KRASG12C-Mutant Lung Cancer

IntroductionSequential anti–programmed cell death protein 1 (PD-1) or anti–programmed death-ligand 1 (PD-L1) followed by small targeted therapy use is associated with increased prevalence of adverse events (AEs) in NSCLC. KRASG12C inhibitor sotorasib may trigger severe immune-mediated hepatotoxicity when used in sequence or in combination with anti–PD-(L)1. This study was designed to address whether sequential anti–PD-(L)1 and sotorasib therapy increases the risk of hepatotoxicity and other AEs. MethodsThis is a multicenter, retrospective study of consecutive advanced KRASG12C-mutant NSCLC treated with sotorasib outside clinical trials in 16 French medical centers. Patient records were reviewed to identify sotorasib-related AEs (National Cancer Institute Common Classification Criteria for Adverse Events—Version 5.0). Grade 3 and higher AE was considered as severe. Sequence group was defined as patients who received an anti–PD-(L)1 as last line of treatment before sotorasib initiation and control group as patients who did not receive an anti–PD-(L)1 as last line of treatment before sotorasib initiation. ResultsWe identified 102 patients who received sotorasib, including 48 (47%) in the sequence group and 54 (53%) in the control group. Patients in the control group received an anti–PD-(L)1 followed by at least one treatment regimen before sotorasib in 87% of the cases or did not receive an anti–PD-(L)1 at any time before sotorasib in 13% of the cases. Severe sotorasib-related AEs were significantly more frequent in the sequence group compared with those in the control group (50% versus 13%, p < 0.001). Severe sotorasib-related AEs occurred in 24 patients (24 of 48, 50%) in the sequence group, and among them 16 (67%) experienced a severe sotorasib-related hepatotoxicity. Severe sotorasib-related hepatotoxicity was threefold more frequent in the sequence group compared with that in the control group (33% versus 11%, p = 0.006). No fatal sotorasib-related hepatotoxicity was reported. Non-liver severe sotorasib-related AEs were significantly more frequent in the sequence group (27% versus 4%, p < 0.001). Severe sotorasib-related AEs typically occurred in patients who received last anti–PD-(L)1 infusion within 30 days before sotorasib initiation. ConclusionsSequential anti–PD-(L)1 and sotorasib therapy are associated with a significantly increased risk of severe sotorasib-related hepatotoxicity and severe non-liver AEs. We suggest avoiding starting sotorasib within 30 days from the last anti–PD-(L)1 infusion.

Liver failure resolved via corticosteroids plus plasma exchange in a patient with hepatocellular carcinoma receiving nivolumab immunotherapy: case report

Background: Therapy with immune checkpoint inhibitors (ICIs) is an option for advanced hepatocellular carcinoma (HCC). Prednisone is recommended for immune-mediated hepatotoxicity (IMH) induced by ICIs in guidelines. However, liver failure is a severe and fetal IMH of ICIs, and little is known about the combined therapy of corticosteroids and plasma exchange (PE) for this IMH.

Hepatotoxicity of immune checkpoint inhibitors: What is Currently Known

This systematic review and network meta-analysis aimed to provide a complete hepatotoxicity profile, hepatotoxicity spectrum, and safety ranking of immune checkpoint inhibitor drugs for cancer treatment. PubMed, Embase, Scopus, CINAHL, Web of Science, psycINFO, Cochrane Library, and ClinicalTrials.gov. websites were searched, and a manual search of relevant reviews and trials up to January 1, 2022, was undertaken. Head-to-head III randomized controlled trials comparing any 2 or 3 of the following treatments or different doses of the same immune checkpoint inhibitor drug were included: programmed death 1 (PD-1), programmed death ligand 1, and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) inhibitors and conventional therapy. We included 106 randomized trials (n=164,782) containing 17 treatment arms. The overall incidence of hepatotoxicity was 4.06%. The rate of fatal liver adverse events was 0.07%. The programmed death ligand 1 inhibitor+targeted therapy drug+chemotherapy group had the highest risk of treatment-related increases in all-grade alanine aminotransferase and aspartate aminotransferase levels, and the differences were significant. For immune-related hepatotoxicity, no significant difference was found between PD-1 and CTLA-4 inhibitors for all-grade hepatotoxicity; however, CTLA-4 inhibitors were associated with a higher risk of grade 3-5 hepatotoxicity than PD-1 inhibitors. The highest incidence of hepatotoxicity and fatality was observed with triple therapy. The overall incidence of hepatotoxicity was similar between different dual regimens. For immune checkpoint inhibitor monotherapy, the overall risk of immune-mediated hepatotoxicity related to CTLA-4 inhibitors did not differ significantly from that of PD-1 inhibitors. There was no direct relationship between the risk of liver injury and drug dose, whether monotherapy or combination therapy was used.

A novel pathologic marker, indoleamine 2,3-dioxygenase 1, for the cholangiopathy of immune checkpoint inhibitors-induced immune mediated hepatotoxicity as adverse events and the prediction of additional ursodeoxycholic acid treatment.

Immune-related adverse events (irAE) has been clarified according the usage of immune checkpoint inhibitors(ICI). We primarily found indoleamine 2,3-dioxygenase 1(IDO-1) as a histologic biomarker for the cholangiopathy of primary biliary cholangitis(PBC). In this study, we evaluated the utility of IDO-1 in identifying ICI-induced immune-mediated hepatotoxicity(IMH). Immunostaining for IDO-1 using liver sections of PBC, ICI-induced IMH and controls, revealed that IDO-1 expression in bile ducts is mostly restricted in PBC and ICI-induced IMH. In ICI-induced IMH, IDO-1-positive bile ducts is found in 2/2 cases of cholangitis type and also positive/focal ducts in 11/15 cases of hepatitis type. Moreover, in 8/13 positive/focal cases, ursodeoxycholic acid as well as steroids were needed to improve liver dysfunction, but just one case (1/4) in IDO-1-negative cases. One IDO-1 positive case of hepatitis type did not receive additional UDCA, but biliary enzymes worsen. In vitro study using cultured human biliary epithelial cells revealed that IDO-1 induction was found with the stimulation of IFN-γ. In conclusion, the presence of IDO-1-positive cells is found in bile ducts in hepatitic type as well as sclerosing cholangitis of ICI-induced IMH. IDO-1 is surely a valuable pathologic marker for diagnosing ICI-induced IMH and also for predicting an additional need of UDCA in clinical practice.

Combination therapy with vincristine, immunoglobulin and glucocorticosteroid (VIG regimen) is very effective for the management of grade 3/4 or steroid-refractory immune-related adverse events (irAE) secondary to PD-1 blockade.

e14577 Background: The management of grade 3/4 or steroid-refractory immune related adverse events (irAE) is based on a paucity of retrospective data analysis. Our initial experience with the combination therapy with Vincristine (VCR), immunoglobulin (IVIG) and glucocorticosteroid (VIG regimen) showed clinical improvement in a wide variety of irAEs. As a result, we recommend the use of VIG regimen for the management of grade 3/4 or steroid-refractory irAEs. Methods: The character and clinical course of irAEs were abstracted from the medical record and analyzed. The components of VIG regimens are as follows: Methylprednisolone (MP) 2-10mg/kg for 3days, VCR 1.4mg/m2 (≤2mg) continuous infusion for 4-8 hours on day 3 once a week with Immunoglobulin (IVIG) 0.4g/kg for 3-5 days. The dose of MP and IVIG will be reduced quickly after irAE improves. VCR 1.4mg/m2 once a week will be used for 1 to 3 times according to the improvement. Clinical improvement was defined as either: documentation of resolution of symptoms and normalisation of biochemical tests or hospital discharge within 14 days. Results: A total of 25 patients had grade3/4 or steroid-refractory irAEs after receiving immune checkpoint inhibitors and then received VIG regimen. Among them, 22 patients have been significantly improved, with an improvement rate of 88%. Twenty-three patents were treated in the inpatient setting (92%). The index grade 3/4 irAE was pneumonitis in 28%, immune mediated hepatotoxicity(IMH) in 28%, rash/SJS/TEN in 24%, cerebritis in 8 % and one case each of ITP, Near blindness and severe oral mucositis. In 7 patients with severe IMH, the range of total bilirubin was 80-481umol/L and ALT 35-5000u/L. Six patients with IMH recover well but one patient did not recover to normal due to IMH complicated with pneumonitis and TEN . Clinical improvement was noted in 22/25 patients (88%), 11 patients (44%) required a single dose, while 12 patients (48%) required two doses, 2 patients(8%) required three doses of VCR 1.4mg/m2 continuous infusion for 4-8 hours. What is impressive is that the two patients with encephalitis were significantly relieved within 2 weeks after using the VIG regimen. One patient with TEN (SCORETEN 3)was significantly improved and discharged from our hospital 11 days after using the VIG regimen. A patient with near-blind eyesight recovered to normal 3 days after using the VIG regimen. Conclusions: VIG regimen may be an effective therapeutic option for the management of grade3/4 or steroid-refractory irAEs secondary to immune checkpoint blockade. However, randomized trials are needed to better elucidate the efficacy and safety of VIG regimen.

Once upon a time the hepatotoxicity…

The liver ensures a large part of xenobiotics metabolism thanks to its sizeable enzymatic equipment, its anatomical localization and its abundant vascularization. However, these various characteristics also make it a privileged target for toxic compounds, particularly in the case of a toxic metabolism. Xenobiotics-induced hepatotoxicity is a major cause of liver damage and a real challenge for clinicians, pharmaceutical industry, and health agencies. Intrinsic, i.e. predictable and reproducible hepatotoxicities occurring at threshold doses are distinguished from idiosyncratic hepatotoxicities, occurring in an unpredictable manner in people with individual susceptibilities. Among them, idiosyncratic immune-mediated hepatotoxicity pathophysiology is still unclear. However, the development of tools to improve the prediction and understanding of these disorders may open avenues to the identification of risk factors and new mechanisms of toxicity.

Clinical features of immune-mediated hepatotoxicity induced by immune checkpoint inhibitors in patients with cancers.

The risk factors and clinical characteristics of ICI-induced immune-mediated hepatotoxicity (IMH) are not fully understood. Thus, the present study sought to clarify the clinical features of IMH. All patients treated with ICIs between September 2014 and April 2019 at our institution were included. Clinical data were retrospectively collected from medical records. The frequency of grade ≥ 2 liver damage, clinical characteristics, and risk factors for developing IMH were examined. Overall, 250 patients (median age 71years; range 30-87years; 202 males and 48 females) were included in the analyses. Forty-five patients had elevated transaminase levels (> threefold the upper limit of normal). Of these, 21 were considered to have IMH. The remaining 24 patients had other causes of elevated transaminase levels. Steroids were administered to 13/21 patients with IMH. Although all patients exhibited improvement, IMH was not associated with the anticancer efficacy of the ICIs or OS. A multivariable analysis revealed that IMH was significantly associated with malignant melanoma (odds ratio [OR] 11.6; 95% confidence interval [CI] 3.5-38.0; P = 0.0002) and ipilimumab-nivolumab combination therapy (OR 61.2; 95% CI 7.9-1275.3; P < 0.0001). Immune-mediated hepatotoxicity occurred in 9.5% of patients treated with ICIs. Appropriate therapeutic interventions are important to avoid affecting the patient's prognosis, and accurate diagnosis of IMH is essential for this purpose. The frequency of IMH varied according to the type of cancer and the drug used, and was significantly higher in patients with malignant melanoma and in patients given ipilimumab-nivolumab combination therapy.

Hepatotoxicity From Immune Checkpoint Inhibitors: A Systematic Review and Management Recommendation

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies targeting immune checkpoint molecules. ICIs are an immunotherapy for the treatment of many advanced malignancies. The advent of ICIs has been a major breakthrough in the field of oncology, a fact recognized by the 2018 Nobel Prize in Physiology or Medicine being awarded for the discovery. The Food and Drug Administration approved the first ICI, ipilimumab, in 2011 for the treatment of metastatic melanoma. Seven ICIs are now used in clinical practice, including nivolumab and pembrolizumab for treatment of advanced hepatocellular carcinoma. ICIs are increasingly used across the spectrum of hepatobiliary neoplasia. The utility of ICI therapy has been limited by immune-related adverse reactions (irAEs) affecting multiple organ systems. Hepatotoxicity is an important irAE, occurring in up to 16% of patients receiving ICIs. Optimizing outcomes in patients receiving ICI therapy requires awareness of and familiarity with diagnosing and management of ICI-induced immune-mediated hepatotoxicity (IMH), including approaches to treatment and ICI dose management. The aim of this review article is to (1) provide a comprehensive, evidence-based review of IMH; (2) perform a systematic review of the management of IMH; and (3) present algorithms for the diagnosis and management of IMH.

Hepatotoxicity associated with tumor immune checkpoint inhibitors

Although tumor immune checkpoint inhibitors therapy brings survival benefits to cancer patients, it also faces many challenges, such as the occurrence of immune-mediated hepatotoxicity. Therefore, an in-depth understanding of the conditions, possible mechanisms, and risk factors that cause liver injury during the treatment of tumor immune checkpoint inhibitors will facilitate better clinical management.

Identification of Candidate Risk Factor Genes for Human Idelalisib Toxicity Using a Collaborative Cross Approach.

Idelalisib is a phosphatidylinositol 3-kinase inhibitor highly selective for the delta isoform that has shown good efficacy in treating chronic lymphocytic leukemia and follicular lymphoma. In clinical trials, however, idelalisib was associated with rare, but potentially serious liver and lung toxicities. In this study, we used the Collaborative Cross (CC) mouse population to identify genetic factors associated with the drug response that may inform risk management strategies for idelalisib in humans. Eight male mice (4 matched pairs) from 50 CC lines were treated once daily for 14 days by oral gavage with either vehicle or idelalisib at a dose selected to achieve clinically relevant peak plasma concentrations (150 mg/kg/day). The drug was well tolerated across all CC lines, and there were no observations of overt liver injury. Differences across CC lines were seen in drug concentration in plasma samples collected at the approximate Tmax on study Days 1, 7, and 14. There were also small but statistically significant treatment-induced alterations in plasma total bile acids and microRNA-122, and these may indicate early hepatocellular stress required for immune-mediated hepatotoxicity in humans. Idelalisib treatment further induced significant elevations in the total cell count of terminal bronchoalveolar lavage fluid, which may be analogous to pneumonitis observed in the clinic. Genetic mapping identified loci associated with interim plasma idelalisib concentration and the other 3 treatment-related endpoints. Thirteen priority candidate quantitative trait genes identified in CC mice may now guide interrogation of risk factors for adverse drug responses associated with idelalisib in humans.

Identification of Novel Metabolites of Vildagliptin in Rats: Thiazoline-Containing Thiol Adducts Formed via Cysteine or Glutathione Conjugation.

Vildagliptin (VG), a dipeptidyl peptidase-4 inhibitor, is used for treating type 2 diabetes. On rare occasions, VG causes liver injury as an adverse reaction. One case report suggested the involvement of immune responses in the hepatotoxicity, but the underlying mechanisms are unknown. We recently reported that VG binds covalently in vitro to l-cysteine to produce a thiazoline acid metabolite, M407, implying that the covalent binding may trigger the immune-mediated hepatotoxicity. There was no evidence, however, that such a thiazoline acid metabolite was formed in vivo. In the present study, we administered a single oral dose of VG to male Sprague-Dawley rats, and detected M407 in plasma. The sum of urinary and fecal excretions of M407 reached approximately 2% of the dose 48 hours postdosing. Using bile duct-cannulated rats, we demonstrated that M407 was secreted into bile as a glucuronide, designated as M583. Another newly identified thiazoline metabolite of VG, the cysteinylglycine conjugate M464, was detected in urine, feces, and bile. The formation of M464 was confirmed by in vitro incubation of VG with glutathione even in the absence of metabolic enzymes. A glutathione adduct against the nitrile moiety M611 was also detected in vitro but not in vivo. In summary, we found three new thiazoline-containing thiol adduct metabolites in VG-administered rats. Nonenzymatic covalent binding of VG would likely occur in humans, and it may be relevant to predicting adverse reactions.

Identification of a novel metabolite of vildagliptin in humans: Cysteine targets the nitrile moiety to form a thiazoline ring

The dipeptidyl peptidase-4 (DPP-4) inhibitor vildagliptin (VG) is used to treat type 2 diabetes. In rare cases, VG-induced liver injury has been reported. One case report suggested that immune responses were involved in the hepatotoxicity. However, the underlying mechanisms of VG-induced hepatotoxicity are uncertain. In the present study, we investigated whether VG has the potential to covalently bind to macromolecules in cells, a process that could initiate immune-mediated hepatotoxicity. For comparison, M20.7, a major metabolite of VG, and other DPP-4 inhibitors were also evaluated. We found that VG and anagliptin (ANG), which both contain a cyanopyrrolidine moiety, rapidly reacted in non-enzymatic manners on co-incubation with l-cysteine. Both VG and ANG had half-lives of 20–30 min. In contrast, incubation with GSH, rather than l-cysteine, failed to decrease the concentrations of VG or ANG. M20.7, sitagliptin, linagliptin, and alogliptin, having no cyanopyrrolidine moiety, were stable on incubation with l-cysteine or GSH. Structural analysis of the VG– and ANG–cysteine adducts, designated M407 and M487, respectively, revealed that the nitrile moieties of VG and ANG were irreversibly converted to a thiazoline acid. In conclusion, we found that VG and ANG have the potential to covalently bind to a thiol residue of l-cysteine in proteins. Such binding may lead to unpredictable immune responses in humans. l-Cysteine, rather than GSH, would likely be useful to detect the potential for covalent binding that could initiate immune-mediated hepatotoxicity.

Approach and management of checkpoint inhibitor-related immune hepatitis.

Immune checkpoint inhibitors have promising clinical activity across multiple gastrointestinal cancers and immune-mediated hepatotoxicity is particularly relevant for this group of patients. In this article we will review the recognition, workup and management of suspected checkpoint inhibitor related immune-hepatitis.

Prediction of drug-induced immune-mediated hepatotoxicity using hepatocyte-like cells derived from human embryonic stem cells.

Drug-induced liver injury (DILI) is a leading cause of liver disease and a key safety factor during drug development. In addition to the initiation events of drug-specific hepatotoxicity, dysregulated immune responses have been proposed as major pathological events of DILI. Thus, there is a need for a reliable cell culture model with which to assess drug-induced immune reactions to predict hepatotoxicity for drug development. To this end, stem cell-derived hepatocytes have shown great potentials. Here we report that hepatocyte-like cells derived from human embryonic stem cells (hES-HLCs) can be used to evaluate drug-induced hepatotoxic immunological events. Treatment with acetaminophen significantly elevated the levels of inflammatory cytokines by hES-HLCs. Moreover, three human immune cell lines, Jurkat, THP-1, and NK92MI, were activated when cultured in conditioned medium obtained from acetaminophen-treated hES-HLCs. To further validate, we tested thiazolidinedione (TZD) class, antidiabetic drugs, including troglitazone withdrawn from the market because of severe idiosyncratic drug hepatotoxicity. We found that TZD drug treatment to hES-HLCs resulted in the production of pro-inflammatory cytokines and eventually associated immune cell activation. In summary, our study demonstrates for the first time the potential of hES-HLCs as an in vitro model system for assessment of drug-induced as well as immune-mediated hepatotoxicity.

Idelalisib given front-line for treatment of chronic lymphocytic leukemia causes frequent immune-mediated hepatotoxicity

AbstractIdelalisib is a small-molecule inhibitor of PI3Kδ with demonstrated efficacy for the treatment of relapsed/refractory chronic lymphocytic leukemia (CLL). To evaluate idelalisib as front-line therapy, we enrolled 24 subjects in a phase 2 study consisting of 2 months of idelalisib monotherapy followed by 6 months of combination therapy with idelalisib and the anti-CD20 antibody ofatumumab. After a median follow-up period of 14.7 months, hepatotoxicity was found to be a frequent and often severe adverse event. A total of 19 subjects (79%) experienced either grade ≥1 ALT or AST elevation during the study, and 13 subjects (54%) experienced grade ≥3 transaminitis. The median time to development of transaminitis was 28 days, occurring before ofatumumab introduction. Younger age and mutated immunoglobulin heavy chain status were significant risk factors for the development of hepatotoxicity. Multiple lines of evidence suggest that this hepatotoxicity was immune mediated. A lymphocytic infiltrate was seen on liver biopsy specimens taken from 2 subjects with transaminitis, and levels of the proinflammatory cytokines CCL-3 and CCL-4 were higher in subjects experiencing hepatotoxicity. All cases of transaminitis resolved either by holding the drug, initiating immunosuppressants, or both, and rates of recurrent toxicity were lower in patients taking steroids when idelalisib was reinitiated. A decrease in peripheral blood regulatory T cells was seen in patients experiencing toxicity on therapy, which is consistent with an immune-mediated mechanism. These results suggest that caution should be taken as drugs within this class are developed for CLL, particularly in younger patients who have not received prior disease-specific therapy. This study was registered at www.clinicaltrials.gov as #NCT02135133.

Co-culture of Hepatocytes and Kupffer Cells as an In Vitro Model of Inflammation and Drug-Induced Hepatotoxicity

Immune-mediated drug-induced hepatotoxicity is often unrecognized as a potential mode of action due to the lack of appropriate in vitro models. We have established an in vitro rat donor-matched hepatocyte and Kupffer cell co-culture (HKCC) model to study immune-related responses to drug exposure. Optimal cell culture conditions were identified for the maintenance of co-cultures based on cell longevity, monolayer integrity, and cytokine response after lipopolysaccharide (LPS) exposure. Hepatocyte monocultures and HKCCs were then used to test a subset of compounds associated with hepatotoxic effects with or without LPS. Cytokine levels and metabolic activity (cytochrome P450 3A [Cyp3A]) were measured after a 48-h exposure to monitor endotoxin-induced changes in acute phase and functional end points. LPS-activated HKCCs, but not hepatocyte monocultures, treated with trovafloxacin or acetaminophen, compounds associated with immune-mediated hepatotoxicity, showed LPS-dependent decreases in interleukin-6 production with concomitant increases in Cyp3A activity. Differential endotoxin- and model-dependent alterations were observed in cytokine profiles and Cyp3A activity levels that corresponded to specific compounds. These results indicate the utility of the HKCC model system to discern compound-specific effects that may lead to enhanced or mitigate hepatocellular injury due to innate or adaptive immune responses.