Utilization of Immunotherapy as a Neoadjuvant Therapy for Liver Transplant Recipients with Hepatocellular Carcinoma.

Background: Hepatocellular carcinoma (HCC) is widely recognized as the predominant type of primary liver malignancy. Orthotopic liver transplantation (OLT) has emerged as a highly effective treatment option for unresectable HCC. Immunotherapies as neoadjuvant options are now being actively investigated in the transplant oncology era to enhance outcomes in patients with HCC. Here, we report our experience with patients with HCC who had received Immune Checkpoint Inhibitors (ICPI) prior to curative OLT. Methods: This was a retrospective cohort that included patients with HCC who received ICPI prior to OLT at a single institution from January 2019 to August 2023. Graft rejection was assessed and reported along with the type of ICPI, malignancy treated, and the timing of ICPI in association with OLT. Results: During this cohort period, six patients with HCC underwent OLT after neoadjuvant ICPI. All patients were male with a median age of 61 (interquartile range: 59-64) years at OLT. Etiology associated with HCC was viral (N = 4) or Non-alcoholic steatohepatitis, NASH (N = 2). Tumor focality was multifocal (N = 4) and unifocal (N = 2). Lymphovascular invasion was identified in four patients. No perineural invasion was identified in any of the patients. All patients received ICPI including atezolizumab/bevacizumab (N = 4), nivolumab/ipilimumab (N = 1), and nivolumab as monotherapy (N = 1). All patients received either single or combined liver-directed/locoregional therapy, including transarterial chemoembolization (TACE), Yttrium-90 (Y90), stereotactic body radiotherapy (SBRT), and radiofrequency ablation (RFA). The median washout period was 5 months. All patients responded to ICPI and achieved a safe and successful OLT. All patients received tacrolimus plus mycophenolate as immunosuppressant (IS) therapy post-OLT and one patient received prednisone as additional IS. No patient had clinical evidence of rejection. Conclusions: This cohort emphasizes the success of tumor downstaging by ICPI for OLT when employed as the neoadjuvant therapy strategy. In addition, this study illustrated the importance of timing for the administration of ICPI before OLT. Given the lack of conclusive evidence in this therapeutic area, we believe that our study lays the groundwork for prospective trials to further examine the impact of ICPI prior to OLT.

Transplant Oncology: An Emerging Discipline of Cancer Treatment.

Transplant oncology is an emerging concept of cancer treatment with a promising prospective outcome. The applications of oncology, transplant medicine, and surgery are the core of transplant oncology to improve patients' survival and quality of life. The main concept of transplant oncology is to radically cure cancer by removing the diseased organ and replacing it with a healthy one, aiming to improve the survival outcomes and quality of life of cancer patients. Subsequently, it seeks to expand the treatment options and research for hepatobiliary malignancies, which have seen significantly improved survival outcomes after the implementation of liver transplantation (LT). In the case of colorectal cancer (CRC) in the transplant setting, where the liver is the most common site of metastasis of patients who are considered to have unresectable disease, initial studies have shown improved survival for LT treatment compared to palliative therapy interventions. The indications of LT for hepatobiliary malignancies have been slowly expanded over the years beyond Milan criteria in a stepwise manner. However, the outcome improvements and overall patient survival are limited to the specifics of the setting and systematic intervention options. This review aims to illustrate the representative concepts and history of transplant oncology as an emerging discipline for the management of hepatobiliary malignancies, in addition to other emerging concepts, such as the uses of immunotherapy in a peri-transplant setting as well as the use of circulating tumor DNA (ctDNA) for surveillance post-transplantation.

Utilization of Immunotherapy for the Treatment of Hepatocellular Carcinoma in the Peri-Transplant Setting: Transplant Oncology View.

Hepatocellular carcinoma (HCC) represents the second most common cause of cancer-related deaths and accounts for over eighty percent of primary liver cancers worldwide. Surgical resection and radiofrequency ablation in small tumors are included in the treatment options for HCC patients with good liver function profiles. According to the Milan Criteria, only a small portion of HCC patients are eligible for liver transplantation due to advanced-stage disease and large tumor size preventing/delaying organ allocation. Recently, the use of anti-programmed cell death protein 1 and programmed cell death ligand 1 (PD-1 and PD-L1) checkpoint inhibitors in the treatment of cancers have evolved rapidly and these therapies have been approved for the treatment of HCC. Immune checkpoint inhibitors have resulted in good clinical outcomes in pre-and post-transplant HCC patients, although, some reports showed that certain recipients may face rejection and graft loss. In this review, we aim to illustrate and summarize the utilization of immune checkpoint inhibitor therapies in pre-and post-liver transplants for HCC patients and discuss the assessment of immune checkpoint inhibitor regulators that might determine liver transplant outcomes.

Utility of Cell-Free DNA Detection in Transplant Oncology.

Transplant oncology is an emerging field in cancer treatment that applies transplant medicine, surgery, and oncology to improve cancer patient survival and quality of life. A critical concept that must be addressed to ensure the successful application of transplant oncology to patient care is efficient monitoring of tumor burden pre-and post-transplant and transplant rejection. Cell-free DNA (cfDNA) detection has emerged as a vital tool in revolutionizing the management of cancer patients who undergo organ transplantation. The advances in cfDNA technology have provided options to perform a pre-transplant evaluation of minimal residual disease (MRD) and post-transplant evaluation of cancer recurrence and transplant rejection. This review aims to provide a comprehensive overview of the history and emergence of cfDNA technology, its applications to specifically monitor tumor burden at pre-and post-transplant stages, and evaluate transplant rejection.

Transplant Oncology: An Evolving Field in Cancer Care.

Transplant oncology is an emerging concept of cancer treatment with a promising prospective outcome. The application of oncology, transplant medicine, and surgery to improve patients' survival and quality of life is the core of transplant oncology. Hepatobiliary malignancies have been treated by liver transplantation (LT) with significant improved outcome. In addition, as the liver is the most common site of metastasis for colorectal cancer (CRC), patients with CRC who have stable unresectable liver metastases are good candidates for LT, and initial studies have shown improved survival compared to palliative systemic therapy. The indications of LT for hepatobiliary malignancies have been slowly expanded over the years in a stepwise manner; however, they have only been shown to improve patient survival in the setting of limited systemic therapy options. This review illustrates the concept and history of transplant oncology as an evolving field for the management of hepatocellular carcinoma, intrahepatic biliary cancer, and liver-only metastasis of non-hepatobiliary carcinoma. The utility of immunotherapy in the transplant setting is discussed as well as the feasibility of using circulating tumor DNA for surveillance post-transplantation.

The Macrophages and Intestinal Symbiosis.

The human intestinal tract is inhabited by trillions of microorganisms and houses the largest pool of macrophages in the human body. Being a part of the innate immune system, the macrophages, the professional phagocytes, vigorously respond to the microbial and dietary antigens present in the intestine. Because such a robust immune response poses the danger to the survival of the non-harmful and beneficial gut microbiota, the macrophages developed mechanisms of recognition and hyposensitivity toward the non-harmful/beneficial inhabitants of the gut. We will discuss the evolution and identity of some of these mechanisms in the following chapter.

Siponimod (Mayzent) Downregulates RhoA and Cell Surface Expression of the S1P1 and CX3CR1 Receptors in Mouse RAW 264.7 Macrophages.

The Siponimod (Mayzent) is a newly developed drug, similar to Fingolimod (FTY720) but with fewer side effects, approved by the Food and Drug Administration for the treatment of multiple sclerosis (MS). The therapeutic effect of siponimod and FTY720 in MS relies on their inhibitory effect on the sphingosine 1-phosphate (S1P) signaling. These drugs bind to the S1P receptors and block the CCL2 chemokine pathway that is responsible for the exit of the immune cells from the lymphoid organs, and circulation, thus preventing immune cell-dependent injury to the nervous system. We recently found that FTY720 beside its effect on the S1P pathway also blocks the RhoA pathway, which is involved in the actin cytoskeleton-related function of macrophages, such as expression/recycling of fractalkine (CX3CL1) receptors (CX3CR1), which direct macrophages to the transplanted organs during the development of the long-term (chronic) rejection. Here we tested the effects of siponimod on the RhoA pathway and the expression of the S1P1 and CX3CR1 receptors in mouse RAW 264.7 macrophages. We found that siponimod downregulates the expression of RhoA protein and decreases the cell surface expression of S1P1 and CX3CR1 receptors. This newly discovered crosstalk between S1P and RhoA/CX3CR1 pathways may help in the development of novel anti-chronic rejection therapies in clinical transplantation.