Efficacy and safety of mycophenolate mofetil in treating immune-related hepatitis induced by immune checkpoint inhibitor use: A retrospective study

Evaluation of mycophenolic acid exposure in a patient with immune-related hepatotoxicity caused by nivolumab and ipilimumab therapy for malignant melanoma: a case report

BACKGROUND

Guidelines such as the National Comprehensive Cancer Network recommend mycophenolate mofetil (MMF) for the treatment of severe steroid-refractory immune-related hepatotoxicity. Mycophenolic acid (MPA) is an active form of MMF that suppresses T- and B-lymphocyte proliferation and immune-related adverse events caused by immune checkpoint inhibitors. MPA has a narrow therapeutic range (37-70 µg·h/mL) and overexposure increases the risk of leukopenia in transplantation. However, the optimal use of MMF in oncology has not yet been established; thus, monitoring plasma MPA concentrations is necessary to avoid excessive immunosuppression in oncology practice.

CASE PRESENTATION

We evaluated plasma MPA concentration in a 75-year-old man with immune-related hepatotoxicity following nivolumab and ipilimumab combination therapy for malignant melanoma. The patient developed severe hepatotoxicity after immunotherapy, and immunosuppressant therapy with corticosteroids was initiated. The patient then developed steroid-refractory immune-related hepatotoxicity; therefore, MMF (1,000 mg twice daily) was co-administered. Seven days after the administration of MMF, the plasma MPA concentration was measured using an enzyme multiplied immunoassay technique. The area under the plasma concentration-time curve for MPA from 0 to 12 h was 41.0 µg·h/mL, and the same dose of MMF was continued. Grade 2 lymphocytopenia, which could be attributed to MMF, was observed during the administration period. Unfortunately, the patient was infected with SARS-CoV-2 and died from respiratory failure.

CONCLUSION

Our patient did not exceed the upper limit of MPA levels as an index of the onset of side effects of kidney transplantation and achieved rapid improvement in liver function. Prompt initiation of MMF after assessment of the steroid effect leads to adequate MPA exposure. Therapeutic drug monitoring should be considered when MMF is administered, to avoid overexposure.

Treatment options for immune-related adverse events associated with immune checkpoint inhibitors

The immunotherapy revolution with the use of immune checkpoint inhibitors (ICIs) started with the clinical use of the first ICI, ipilimumab, in 2011. Since then, the field of ICI therapy has rapidly expanded - with the FDA approval of 10 different ICI drugs so far and their incorporation into the therapeutic regimens of a range of malignancies. While ICIs have shown high anti-cancer efficacy, they also have characteristic side effects, termed immune-related adverse events (irAEs). These side effects hinder the therapeutic potential of ICIs and, therefore, finding ways to prevent and treat them is of paramount importance. The current protocols to manage irAEs follow an empirical route of steroid administration and, in more severe cases, ICI withdrawal. However, this approach is not optimal in many cases, as there are often steroid-refractory irAEs, and there is a potential for corticosteroid use to promote tumour progression. This review surveys the current alternative approaches to the treatments for irAEs, with the goal of summarizing and highlighting the best attempts to treat irAEs, without compromising anti-tumour immunity and allowing for rechallenge with ICIs after resolution of the irAEs.

Clinical characteristics and prognostic implications of immune-related hepatitis in patients with advanced non-small cell lung cancer treated with immune checkpoint inhibitors: a retrospective study

Background

With the widespread use of immune checkpoint inhibitors (ICIs), patients inevitably experience immune-related adverse events (irAEs). Therefore, the study was conducted on the clinical characteristics and outcomes of patients with non-small cell lung cancer (NSCLC) with immune-related hepatitis (ir-hepatitis).

Methods

We identified patients with advanced NSCLC who developed ir-hepatitis after immunotherapy between June 2016 and December 2022. Their irAEs were categorized according to the Common Terminology Criteria for Adverse Events version 4.03 (CTCAE 4.03). Kaplan-Meier curves and log-rank tests were used to analyze survival.

Results

A total of 35 patients were enrolled in the study. The numbers of mild (grade 1-2) and severe (grade 3-4) ir-hepatitis cases were 13 (grade 1, 3; grade 2, 10) and 22 (grade 3, 17; grade 4, 5), respectively. The median onset time of ir-hepatitis was 1.6 months. The median progression-free survival (mPFS) was 8.3 months. PFS differed between patients with early ir-hepatitis developing within two treatment cycles and those with ir-hepatitis developing more than two treatment cycles (5.5 vs. 12.7 months, P=0.004). Patients with severe rather than mild ir-hepatitis tended to poorer PFS survival (5.8 vs. 11.2 months, P=0.130). The appearance of ir-hepatitis within two treatment cycles (P=0.002) and higher severity grades of ir-hepatitis (P=0.005) were independent risk factors for PFS.

Conclusions

Early and severe ir-hepatitis are associated with worse survival benefits, which still required more basic and perspective studies.

Achilles' Heel of currently approved immune checkpoint inhibitors: immune related adverse events

Immunotherapy has revolutionized the cancer treatment landscape by opening up novel avenues for intervention. As the use of immune checkpoint inhibitors (ICIs) has exponentially increased, so have immune-related adverse events (irAEs). The mechanism of irAEs may involve the direct damage caused by monoclonal antibodies and a sequence of immune responses triggered by T cell activation. Common side effects include dermatologic toxicity, endocrine toxicity, gastrointestinal toxicity, and hepatic toxicity. While relatively rare, neurotoxicity, cardiotoxicity, and pulmonary toxicity can be fatal. These toxicities pose a clinical dilemma regarding treatment discontinuation since they can result in severe complications and necessitate frequent hospitalization. Vigilant monitoring of irAEs is vital in clinical practice, and the principal therapeutic strategy entails the administration of oral or intravenous glucocorticoids (GSCs). It may be necessary to temporarily or permanently discontinue the use of ICIs in severe cases. Given that irAEs can impact multiple organs and require diverse treatment approaches, the involvement of a multidisciplinary team of experts is imperative. This review aims to comprehensively examine the pathogenesis, clinical manifestations, incidence, and treatment options for various irAEs.

Immunosuppressant mycophenolate mofetil for patients with steroid-refractory immune-related hepatitis induced by checkpoint inhibitors in oncology

BACKGROUND

Immune-checkpoint inhibitor (ICI) hepatitis, which does not improve with steroids and requires additional immunosuppressant, is defined as steroid-refractory ICI hepatitis. The outcome of patients with steroid-refractory ICI hepatitis remains poorly determined. Herein, we investigated the incidence, clinical features, and outcome of patients treated with second-line immunosuppressant for steroid-refractory ICI hepatitis.

METHODS

This is a retrospective analysis of patients who presented ICI hepatitis from 1st June 2016 to 30th September 2022. Steroid-refractory ICI hepatitis was defined as no clinical and biological improvement after systemic steroid therapy ≥1 mg/kg/d. Main objectives were to assess the frequency and risk factors associated with steroid-refractory ICI hepatitis and to evaluate the efficacy of second-line immunosuppressants.

RESULTS

In total, 130 patients with grade ≥3 ICI hepatitis were screened, of them 60 (46.2%) were treated with systemic steroids. In total, 11/130 (8.5%) had steroid-refractory hepatitis. Statistically significant factors associated with steroid-refractory hepatitis included previous liver comorbidities (54.5% versus 11.6%; p < 0.01), hyperbilirubinemia (p < 0.001), and general symptoms (fever, jaundice, ascites, and/or encephalopathy) associated with hepatitis (72.7% versus 30.8%; p = 0.015). The 11 patients with steroid-refractory hepatitis were treated with mycophenolate mofetil. In total, resolution or return to grade ≤1 for hepatitis was observed in 81.8% (9/11) of patients.

CONCLUSIONS

Steroid-refractory ICI hepatitis accounted for 8.5% of patients with grade ≥3 immune-related hepatitis and was statistically associated with previous liver comorbidities, hyperbilirubinemia, and general symptoms. Mycophenolate mofetil was a suitable option of therapy for steroid-refractory ICI hepatitis.