Ritonavir's Evolving Role: A Journey from Antiretroviral Therapy to Broader Medical Applications

Ritonavir is a protease inhibitor initially developed for HIV treatment that is now used as a pharmacokinetic booster for other antiretrovirals due to it being a cytochrome P450 3A4 enzyme and P-glycoprotein inhibitor. Consequently, ritonavir is of special interest for repurposing in other diseases. It had an important role in battling the COVID-19 pandemic as a part of the developed drug Paxlovid® in association with nirmatrelvir and has shown effects in hepatitis and other pathogenic diseases. Ritonavir has also shown promising results in overcoming drug resistance and enhancing the efficacy of existing chemotherapeutic agents in oncology. Evidence of cancer repurposing potential was demonstrated in cancers such as ovarian, prostate, lung, myeloma, breast, and bladder cancer, with several mechanisms of action presented. In vitro studies indicate that ritonavir alone can inhibit key pathways involved in cancer cell survival and proliferation, causing apoptosis, cell cycle arrest, endoplasmic reticulum stress, and metabolic stress due to the inhibition of molecules like heat shock protein 90 and cyclin-dependent kinases. Ritonavir also causes resistant cells to become sensitized to anticancer drugs like gemcitabine or docetaxel. These findings indicate that repurposing ritonavir, either on its own or in combination with other medications, could be a promising approach for treating various diseases. This is particularly relevant in cancer therapy, where ritonavir repurposing is the central focus of this review.

High success rates for the use of ombitasvir/paritaprevir/ritonavir containing regimens in treatment of naïve and experienced chronic hepatitis C genotype 4: Real world results

INTRODUCTION AND AIMS

Treatment of hepatitis C virus (HCV) genotype 4 patient with fixed dose combination of ombitasvir-paritaprevir-ritonavir plus ribavirin (OBV/rPTV/RBV) has been proven efficacy and safety in many clinical trials. The current study reports the efficacy and safety of OBV/rPTV/RBV (for treatment-naïve), and OBV/rPTV/RBV/sofosbuvir (SOF) (for treatment-experienced), in chronic HCV genotype 4 patients in real life settings.

METHODS

Prospective cohort study including all adult chronic HCV genotype 4 patients who were scheduled to receive OBV/rPTV/RBV ± SOF for 12 or 24 weeks in New Cairo Viral Hepatitis Treatment Center. The primary efficacy endpoint was a virologic response at posttreatment week 12 (SVR12). Changes in hematological parameters, liver biochemical profile and fibrosis-4 index (FIB-4), as well as clinical and laboratory adverse events (AEs) across follow up visits (week 4, end of treatment [EOT], and SVR12), were recorded.

RESULTS

Our study included 325 patients (age; 47.63 ± 12.63 years, 55.38% [n = 180] men). Most of the included patients (89.85%, n = 292) were treatment naïve and only 7% (n = 23) had liver cirrhosis. Overall, SVR12 was attained by 98.44% (316 of 321) of the patients; 97.15% (307 of 316) of patients who received 12 weeks of OBV/rPTV/RBV ± SOF and 100% (9 of 9) of patients who received 24 weeks of OBV/rPTV/RBV as assessed by modified intention to treat analysis. There was a significant improvement of baseline alanine aminotransferase, aspartate aminotransferase, hemoglobin, FIB-4 at SVR12 (P < 0.05). The most common reported AEs were anemia (n = 106), fatigue (n = 41) and elevated indirect bilirubin (n = 37).

CONCLUSION

OBV/rPTV/RBV (±SOF) is a highly effective therapy for chronic HCV patients in real life settings.

Treatment of HCV infection in Poland at the beginning of the interferon-free era-the EpiTer-2 study

The aim of the EpiTer-2 study was to analyse patient characteristics and their medication for HCV infection in Poland at the beginning of the interferon-free era. Analysis of data of HCV infected patients treated during the initial period of availability of interferon-free regimens in Poland, who started therapy after 1 July 2015 and had available an efficacy evaluation report before 30 June 2017 was undertaken. A total of 2879 patients with chronic hepatitis C were entered, including 46% with liver cirrhosis. The most common was genotype 1b (86.8%). The study population was gender balanced, the majority of patients were overweight or obese and 69% presented comorbidities, with the highest prevalence that for hypertension. More than half of patients were retreated due to failure of previous therapy with pegylated interferon and ribavirin. Almost two-third of patients received current therapy with ombitasvir/paritaprevir/ritonavir±dasabuvir (OPrD) ±ribavirin. Other patients received mostly sofosbuvir-based regimens including combination with ledipasvir and pegylated interferon and ribavirin for genotype 3-infected patients. Efficacy of treatment in the whole study population measured as intent-to-treat analysis was 95%. The most frequent regimen, administered for patients infected with genotype 1b, was 12 weeks of OPrD, resulting in an SVR rate of 98%. At least one adverse event was reported in 38% of patients, and the death rate was 0.8%. In conclusion, data from the EpiTer-2 study confirmed the excellent efficacy and safety profile of the real-world experience with recently introduced therapeutic options for genotype 1 HCV infection, but demonstrated weakness of the current therapeutic programme regarding genotype 3 infections.

Evaluation the efficacy and safety of simultaneous splenectomy in liver transplantation patients: A meta-analysis

BACKGROUND

Simultaneous splenectomy during liver transplantation (LT) is debated. The present meta-analysis assessed the efficacy and safety of splenectomy on the outcome of LT patients.

METHODS

We searched PubMed, Embase, and Wanfang databases for relevant studies published until the date of July 15, 2017. Quality assessment of the included studies was performed using a modified Newcastle-Ottawa Scale judgment. The data were analyzed using RevMan5.3 software.

RESULTS

A total of 16 studies consisting of 2198 patients (892 patients received splenectomy during LT [SPLT group] and 1306 patients received LT only [LT group]) were included in the present meta-analysis. Efficacy analysis revealed that pooled hazard ratio for overall survival (OS) between 2 groups was not significantly different (hazard ratio = 1.03; 95% confidence interval [CI]: 0.71-1.50). SPLT group had less postoperative rejection (odds ratio [OR] = 0.63, 95% CI: 0.50-0.79) and small for size syndrome (OR = 0.23, 95% CI: 0.07-0.79). SPLT group had significantly lower preoperative platelet (mean difference [MD] = -17.23, 95% CI: -19.54, -14.91), but significantly higher postoperative platelet (MD = 170.45, 95% CI: 108.33-232.56). Conversely, SPLT group had significant higher preoperative portal pressure (MD = 1.54, 95% CI: 0.75-2.33) and significant lower postoperative portal pressure (MD = -1.17, 95% CI: -2.24, -0.11). Safety analysis revealed that SPLT group had significantly longer operation time (MD = 56.66, 95% CI: 35.96-77.35), more intraoperative blood loss (MD = 1.08, 95% CI: 0.25-1.91), and more intraoperative red blood cell (RBC) transfusion (MD = 3.77, 95% CI: 3.22-4.33). Furthermore, SPLT group had significantly higher incidence of postoperative hemorrhage (OR = 3.07, 95% CI: 1.92-4.91), postoperative thrombosis (OR = 3.63, 95% CI: 1.06-12.45), and perioperative infection (OR = 2.62, 95% CI: 1.76-3.90). In addition, perioperative mortality was significantly higher in the SPLT group (OR = 3.14, 95% CI: 1.31-7.52). Postoperative hospital stay did not differ significantly between 2 groups (OR = -1.75, 95% CI: -3.66-0.16).

CONCLUSIONS

Splenectomy benefits LT patients in increasing platelet count. However, splenectomy is a morbid procedure as splenectomy increases operation time, intraoperative blood loss, intraoperative RBC transfusion, and postoperative complications. Splenectomy does not improve OS but increase perioperative mortality. Therefore, splenectomy should be performed only in selective patients.

Direct-acting agents for hepatitis C virus before and after liver transplantation

Chronic hepatitis C virus (HCV) infection remains a widespread public health concern and many people are infected with HCV. HCV is one of the leading indications for liver transplantation. Direct-acting antiviral agents (DAAs) against HCV have changed the course of chronic HCV infection, however, making it a curable disease. DAA treatment may be initiated before or after liver transplantation. In the present review, we present the available data on DAA treatment of HCV in liver transplant recipients.

Successful twice interrupted therapy of HCV infection in patients with cirrhosis with hepatocellular carcinoma before and after liver transplantation

We are presenting the case study of the patient diagnosed at the age of 37 with liver cirrhosis due to genotype 1b hepatitis C virus infection. At the age of 46, he was diagnosed with hepatocellular carcinoma with subsequent resection of the tumour in May 2015. In December 2015, the treatment was started with ombitasvir, paritaprevir/ritonavir and dasabuvir (3D) with ribavirin (RBV) 1000 mg per day. After 24 days of this treatment, the patient received a deceased donor liver transplantation, followed by 18-day interruption of 3D therapy. Due to the anaemia, RBV dose was reduced to 600 mg per day for the rest of the treatment. At the 11th week of 3D+RBV treatment, there was another 8-day long discontinuation of therapy due to the postoperative wound infection. In total, the patient received 24 weeks of 3D+RBV treatment, achieving sustained virological response at week 24 post-treatment.