Unlocking the Potential of Arginine Deprivation Therapy: Recent Breakthroughs and Promising Future for Cancer Treatment.

Arginine is a semi-essential amino acid that supports protein synthesis to maintain cellular functions. Recent studies suggest that arginine also promotes wound healing, cell division, ammonia metabolism, immune system regulation, and hormone biosynthesis-all of which are critical for tumor growth. These discoveries, coupled with the understanding of cancer cell metabolic reprogramming, have led to renewed interest in arginine deprivation as a new anticancer therapy. Several arginine deprivation strategies have been developed and entered clinical trials. The main principle behind these therapies is that arginine auxotrophic tumors rely on external arginine sources for growth because they carry reduced key arginine-synthesizing enzymes such as argininosuccinate synthase 1 (ASS1) in the intracellular arginine cycle. To obtain anticancer effects, modified arginine-degrading enzymes, such as PEGylated recombinant human arginase 1 (rhArg1-PEG) and arginine deiminase (ADI-PEG 20), have been developed and shown to be safe and effective in clinical trials. They have been tried as a monotherapy or in combination with other existing therapies. This review discusses recent advances in arginine deprivation therapy, including the molecular basis of extracellular arginine degradation leading to tumor cell death, and how this approach could be a valuable addition to the current anticancer arsenal.

Peginterferon Is Superior to Nucleos(t)ide Analogues for Prevention of Hepatocellular Carcinoma in Chronic Hepatitis B.

BACKGROUND: Clinical factors associated with hepatocellular carcinoma (HCC) have been extensively studied in antiviral treatment-naive patients with chronic hepatitis B virus (HBV) infection but not in treatment-experienced patients. Owing to the wide availability of antiviral agents that effectively suppress HBV replication, we investigated HCC risk factors in treatment-experienced patients. METHODS: In a cohort of 330 patients who underwent pretherapeutic liver biopsy, we analyzed the HCC incidence in relationship to clinical parameters. Ultra-deep sequencing of the viral genome was performed on 11 entecavir-treated and pegylated interferon (peginterferon)-treated patients. RESULTS: Initial univariate/multivariate explorations indicated that cirrhosis and antiviral treatment were independently associated with HCC occurrence. The peginterferon-experienced patients had a lower HCC incidence than the nucleos(t)ide analogue-treated patients (P = .011). The peginterferon and entecavir monotherapy groups also differed in HCC incidence (P = .018). Results of analysis of baseline-matched subgroups concurred with cohort analysis (P = .009 for comparison of peginterferon-experienced vs nucleotide analogue-treated patients; P = .022 for comparison of peginterferon- vs entecavir-treated patients). Viral loads of entecavir-treated patients were constantly suppressed to levels lower than those of peginterferon-treated patients (P < .001). Oncogenic surface antigen truncation mutations were detected in entecavir-treated patients with HCC but not in peginterferon-treated patients (P = .015). CONCLUSIONS: Treatment by peginterferon was associated with a lower HCC incidence than nucleos(t)ide-analogue treatment in chronic HBV infection.

Efficacy, safety, and pharmacokinetics of capsid assembly modulator linvencorvir plus standard of care in chronic hepatitis B patients.

BACKGROUND/AIMS: Four-week treatment of linvencorvir (RO7049389) was generally safe and well tolerated, and showed anti-viral activity in chronic hepatitis B (CHB) patients. This study evaluated the efficacy, safety, and pharmacokinetics of 48-week treatment with linvencorvir plus standard of care (SoC) in CHB patients. METHODS: This was a multicentre, non-randomized, non-controlled, open-label phase 2 study enrolling three cohorts: nucleos(t)ide analogue (NUC)-suppressed patients received linvencorvir plus NUC (Cohort A, n=32); treatment-naïve patients received linvencorvir plus NUC without (Cohort B, n=10) or with (Cohort C, n=30) pegylated interferon-α (Peg-IFN-α). Treatment duration was 48 weeks, followed by NUC alone for 24 weeks. RESULTS: 68 patients completed the study. No patient achieved functional cure (sustained HBsAg loss and unquantifiable HBV DNA). By Week 48, 89% of treatment-naïve patients (10/10 Cohort B; 24/28 Cohort C) reached unquantifiable HBV DNA. Unquantifiable HBV RNA was achieved in 92% of patients with quantifiable baseline HBV RNA (14/15 Cohort A, 8/8 Cohort B, 22/25 Cohort C) at Week 48 along with partially sustained HBV RNA responses in treatment-naïve patients during follow-up period. Pronounced reductions in HBeAg and HBcrAg were observed in treatment-naïve patients, while HBsAg decline was only observed in Cohort C. Most adverse events were grade 1-2, and no linvencorvir-related serious adverse events were reported. CONCLUSION: 48-week linvencorvir plus SoC was generally safe and well tolerated, and resulted in potent HBV DNA and RNA suppression. However, 48-week linvencorvir plus NUC with or without Peg-IFN did not result in the achievement of functional cure in any patient.

Vaniprevir with pegylated interferon alpha-2a and ribavirin in treatment-naïve patients with chronic hepatitis C: a randomized phase II study.

UNLABELLED: Vaniprevir (MK-7009) is a macrocyclic hepatitis C virus (HCV) nonstructural protein 3/4A protease inhibitor. The aim of the present phase II study was to examine virologic response rates with vaniprevir in combination with pegylated interferon alpha-2a (Peg-IFN-α-2a) plus ribavirin (RBV). In this double-blind, placebo-controlled, dose-ranging study, treatment-naïve patients with HCV genotype 1 infection (n = 94) were randomized to receive open-label Peg-IFN-α-2a (180 µg/week) and RBV (1,000-1,200 mg/day) in combination with blinded placebo or vaniprevir (300 mg twice-daily [BID], 600 mg BID, 600 mg once-daily [QD], or 800 mg QD) for 28 days, then open-label Peg-IFN-α-2a and RBV for an additional 44 weeks. The primary efficacy endpoint was rapid viral response (RVR), defined as undetectable plasma HCV RNA at week 4. Across all doses, vaniprevir was associated with a rapid two-phase decline in viral load, with HCV RNA levels approximately 3 log(10) IU/mL lower in vaniprevir-treated patients, compared to placebo recipients. Rates of RVR were significantly higher in each of the vaniprevir dose groups, compared to the control regimen (68.8%-83.3% versus 5.6%; P < 0.001 for all comparisons). There were numerically higher, but not statistically significant, early and sustained virologic response rates with vaniprevir, as compared to placebo. Resistance profile was predictable, with variants at R155 and D168 detected in a small number of patients. No relationship between interleukin-28B genotype and treatment outcomes was demonstrated in this study. The incidence of adverse events was generally comparable between vaniprevir and placebo recipients; however, vomiting appeared to be more common at higher vaniprevir doses. CONCLUSION: Vaniprevir is a potent HCV protease inhibitor with a predictable resistance profile and favorable safety profile that is suitable for QD or BID administration.

Emergence of hepatitis B virus S gene mutants in patients experiencing hepatitis B surface antigen seroconversion after peginterferon therapy.

UNLABELLED: With anti-hepatitis B virus (anti-HBV) therapy using peginterferon, the seroconversion of hepatitis B surface antigen (HBsAg), which is considered a cure of the disease, can be achieved in a small percentage of patients. Eight of 245 consecutive patients (3.27%) with chronic hepatitis B who received peginterferon therapy at our center achieved HBsAg seroclearance. Surprisingly, two of the eight patients remained viremic according to standard HBV DNA assays. The coding regions of the HBV pre-S/S gene, which were derived from serial serum samples, were analyzed. Site-directed mutagenesis experimentation was performed to verify the phenotypic alterations in Huh-7 cells. In patient 1, an sT125A mutant developed during the HBsAg-negative stage and constituted 11.2% of the viral population. The HBV DNA level was 2.73 × 10(4) IU/mL at the time of detection. This mutant was not detectable in the HBsAg-positive stages. A phenotypic study of Huh-7 cells showed a significant reduction of antigenicity. In patient 2, an sW74* truncation mutation was found during the HBsAg-negative stage and constituted 83.1% of the viral population. The HBV DNA level was 4.12 × 10(4) IU/mL at the time of detection. A phenotypic study of Huh-7 cells showed a complete loss of antigenicity. Patient 2 subsequently experienced an episode of hepatitis relapse 7 months after the end of treatment and was negative for HBsAg throughout the hepatitis flare. CONCLUSION: During antiviral therapy with peginterferon, the achievement of HBsAg seroconversion does not necessarily indicate viral eradication. The emergence of S gene mutants is another possibility, and a relapse with HBsAg-negative hepatitis can occur.

Comparison of Compliance and Efficacy of Pegylated Interferon α-2a and α-2b in Adults with Chronic Hepatitis C.

This study compares treatment completion rates and outcomes in hepatitis C virus (HCV) patients between those aged <60 and ≥60 years receiving pegylated interferon (PEG-IFN) α-2a or α-2b combined with ribavirin. No significant differences were found in treatment completion rates and virological responses between age-stratified patients or between genotype-stratified patients receiving PEG-IFN α-2a versus PEG-IFN α-2b. Significantly more patients ≥60 years of receiving PEG-IFN α-2b exhibited an early virological response compared to those receiving PEG-IFN α-2a (P = 0.002); for patients <60 years of age, treatment outcomes were similar between the 2 groups. More liver fibrosis was observed in patients with HCV of genotype 1 than in those with genotypes 2 or 3. Mean changes in pre- and post-treatment fibrosis variables (bilirubin, platelet count, liver enzymes, FIB-4, and APRI) in HCV genotype 1 patients were greater in those receiving PEG-IFN α-2b than in those receiving PEG-IFN α-2a. Significant differences were not observed between age- and HCV genotype-stratified patients receiving PEG-IFN α-2a and -α-2b, but α-2b appears to have a modest efficacy advantage over α-2b, particularly in male HCV patients ≥60 years of age.

Gene gun bombardment with DNA-coated gold particles is a potential alternative to hydrodynamics-based transfection for delivering genes into superficial hepatocytes.

Although in vivo nonviral gene delivery to the liver is critical for hepatic gene therapy, there are a number of technical obstacles. Enhanced green fluorescent protein (EGFP)-encoding DNA was coated onto gold particles (gold-DNA), dissolved in phosphate-buffered saline (pure DNA), and prepared as a polymer adjuvant (jetPEI)-galactosidase solution (polymer-DNA). Murine liver transfection was attempted by nonviral approaches, which included hydrodynamics-based transfection (HBT) of pure DNA, transport and transhepatic injection of polymer-DNA, and gene gun bombardment with pure DNA, gold-DNA, and polymer-DNA. Only HBT and gene gun bombardment yielded significant numbers of EGFP(+) hepatocytes. With the exception of the edge of the liver, HBT had a whole-liver transfection rate of 20% under optimized conditions. HBT resulted in marked hepatic infarctions, most prominently at the edge of the liver. For gene gun bombardment, the transfection rate was pressure dependent and limited to 15% for gold-DNA. Triple or quadruple bombardment at 30 psi resulted in a transfection rate comparable to that of a single bombardment at higher pressure, but was associated with minimal scattered hepatic necrosis. The EGFP(+) hepatocytes were located mainly in the superficial layers. We conclude that both HBT and gene gun bombardment yielded efficient murine hepatocyte transfection in vivo. Severe hepatic infarction impedes foreign gene expression in the superficial hepatocytes after HBT. Repeated bombardment with gold-DNA, using an accelerated particle gene gun at 30 psi, is a potential alternative to HBT for delivering genes to superficial hepatocytes in vivo, although gold-related hepatic necrosis is a persistent problem.

Clinical Predictors for Neutrophil-to-Lymphocyte Ratio Changes in Patients with Chronic Hepatitis B Receiving Peginterferon Treatment.

BACKGROUND: A lower neutrophil-to-lymphocyte ratio (NLR) was found to be associated with better clinical outcomes in hepatitis B-related liver cirrhosis and hepatocellular carcinoma. We aimed to identify pre-therapeutic variables capable of predicting NLR changes in patients with hepatitis B receiving peginterferon therapy. PATIENTS AND METHODS: The baseline clinicopathological data were analyzed to correlate with NLR changes before and 1 year after peginterferon treatment in 71 patients with hepatitis B. RESULTS: Univariate analysis revealed that pre-treatment NLR itself negatively predicted NLR changes following peginterferon treatment (odds ratio(OR)=0.320, p=0.013). Further analysis identified pre-treatment NLR, hemoglobin and hepatitis B surface antigen level as independent predictors for NLR changes (adjusted p=0.028, 0.005, and 0.028, respectively). A predictive score composed of these three factors had an area under the curve of 76.5% (p<0.001). CONCLUSION: Pretreatment NLR, hemoglobin and hepatitis B surface antigen level in combination, effectively predicted NLR changes following peginterferon treatment.

A double-blind randomized controlled study to evaluate the efficacy of low-dose oral interferon-alpha in preventing hepatitis C relapse.

Low-dose oral interferon could exert immune-modulating effects in human. We conducted a clinical trial to investigate the efficacy of oral interferon-alpha in preventing hepatitis C relapse. Totally 169 genotype 1b chronic hepatitis C patients having achieved end-of-therapy virological clearance were randomized to receive interferon-alpha lozenge 500 IU/day (n=59), 1,500 IU/day (n=53), or placebo (n=57) for 24 weeks. Overall, no significant differences were found for the relapse rates in the 3 groups (P>0.05). However, in patients with fibroindex 1.4-1.7, relapse occurred in 1/12 (8.3%) 500 IU-group patients versus 9/21 (42.9%) patients of the other groups (P=0.05). In 158 patients receiving at least 4 weeks of oral interferon, significantly higher platelet count was found at the end of trial in the 500 IU group (P=0.003). In thrombocytopenic patients, a significantly expedited recovery of platelet count was found in the 500 IU group (P=0.002). No drug-related severe adverse events were reported. In conclusion, at 500 IU/day, oral interferon exerted a borderline suppression effect of virological relapse in chronic hepatitis C patients with mild liver fibrosis. Additionally, it significantly expedited platelet count recovery after the end of peginterferon therapy.

Distinct patterns of the lipid alterations between genotype 1 and 2 chronic hepatitis C patients after viral clearance.

BACKGROUND: The hepatitis C virus (HCV) genotype-specific impacts on the host metabolic alterations remained inconclusive. METHODS: A prospective study including 229 (118 genotype 1 (G1) and 111 G2) consecutive chronic HCV patients who had completed a course of anti-HCV treatment and underwent pre- and 24 weeks post-treatment surveys of metabolic profiles was conducted. Patients were stratified according to the therapeutic response, viral genotype and baseline insulin resistance (IR: homeostasis model assessments of IR (HOMA-IR) ≥ 2.5). Paired t-tests were used to compare the pre- and post-treatment variables. RESULTS: Significant post-therapeutic increases in cholesterol, triglyceride, HDL, LDL, apolipoprotein A1 and apolipoprotein B were observed in patients with sustained virological response (SVR) but not in those without. Among those with SVR, post-therapeutic increases in HDL (p<0.001) and apolipoprotein A1 (p = 0.012) were only found in G2, whereas increased triglyceride/HDL (p = 0.01) ratios were only found in G1 patients. When stratified by baseline IR among those with SVR, a significant increase in post-treatment HDL (p = 0.019) and apolipoprotein A1 (p = 0.012) but a decrease in HOMA-IR (p = 0.04), C-peptide (p = 0.019) and hemoglobin A1c (p = 0.047) were found in patients with baseline IR; a significant increase in HOMA-IR (p = 0.002) was found in patients without baseline IR. The latter change was observed only in G1 (p = 0.01) but not G2 patients. Although the pre-treatment metabolic profiles of G1 and G2 patients were indifferent, G1 had higher post-treatment triglyceride/HDL ratios (p = 0.041) and triglyceride (p = 0.044) levels than G2 patients. CONCLUSIONS: G2 benefit more than G1 patients from viral clearance in metabolic alterations, particularly in those without baseline IR.

Impact of the novel hepatotropic viruslike agent NV-F during chronic hepatitis C virus infection.

NV-F is a novel hepatotropic viruslike agent. To investigate the impact of the NV-F agent during chronic hepatitis C virus (HCV) infection, 101 consecutive patients with chronic HCV infection were evaluated. NV-F DNA in serum samples and NV-F antigen expression in liver tissues were assessed. All patients subsequently received a 6-month course of interferon-based antiviral therapy. Of the 101 patients, 30 (29.7%) were positive for serum NV-F DNA. Immunohistochemical analysis revealed positive NV-F antigen expression in the liver in 14 of these 30 patients. Patients positive for serum NV-F DNA had significantly higher serum aminotransferase levels (P < .001) and higher Knodell histology activity index values (P < .001). The sustained virological response rate for HCV clearance was not significantly different between patients with and those without detectable serum NV-F DNA. In conclusion, coinfection of the NV-F agent in chronic HCV infection is associated with more severe hepatitis activity.