Search Results (259)

Background: Traditional genotype-guided dosing often fails to predict real-time variability in the metabolic phenotype during complex polypharmacy. This secondary analysis of a retrospective cohort aims to elucidate mechanisms underlying real-time phenoconversion during antipsychotic therapy, focusing on homozygous loss-of-function CYP3A5*3/*3 non-expressors. Methods: Using an additive phenoconversion model that integrates a genotype-derived baseline with environmental modifiers for drug–drug interactions (DDI), systemic inflammation (CRP), and renal function (eGFR), we demonstrate that the expressed metabolic phenotype is a dynamic, context-dependent construct that can markedly diverge from the genotype-predicted state. Objectives: Our data show that patients with CYP3A5*3/*3 and CYP3A inhibitors (e.g., ritonavir) had a quetiapine plasma concentrations reached 1850 ng/mL, corresponding to 3.7-fold above the internationally accepted therapeutic reference range of 100–500 ng/mL. Acute systemic inflammation (CRP > 50 mg/L) induced a functional poor metabolizer phenotype (P_act < −0.9) in individuals with a genotypic normal metabolizer status. In contrast, strong inducers such as carbamazepine, phenytoin, and heavy smoking promoted an ultra-rapid metabolizer state (CL_ind > 4.0 L/h, quetiapine < 30 ng/mL), consistent with treatment failure. In this cohort, the additive P_act model showed a strong association with observed clearance and identified clinically relevant phenoconversion mechanisms not predicted from genotype alone. Conclusions: These results support a dynamic, multi-parametric approach that integrates pharmacogenomics, therapeutic drug monitoring, biomarker profiling (CRP, eGFR), and structured DDI assessment to enable higher-resolution, real-time phenotype tracking and more informed dose individualization in high-risk psychiatric polypharmacy. Full article

Drug repurposing presents as a promising strategy in oncology, particularly for urological prostate and bladder cancers, where resistance to current therapy remains a challenge. This study evaluated the anticancer potential of three antiretroviral drugs, namely ritonavir (RIT), saquinavir (SAQ), and rilpivirine (RPV), in PC-3 and UM-UC-5 cancer cell lines, using MTT, clonogenic, wound healing, toxicity assessment with fibroblast cells, and DCFDA assays; this last method included efavirenz (EFV) and etravirine (ETV) for intracellular reactive oxygen species (ROS) production. RIT and SAQ showed stronger antiproliferative effects than RPV, with lower concentration- and cell-line-dependent activity, while clonogenic assays confirmed a reduction in long-term proliferation, particularly for RIT in both cell lines and SAQ for UM-UC-5. In contrast, effects on cell migration were limited for all drugs. ROS production was cell-dependent, with EFV increasing ROS in PC-3 and SAQ and RIT in UM-UC-5 cells. Generally, all drugs showed minimal toxicity in non-malignant cells, with SAQ exhibiting some toxicity but only for concentrations higher than those required for anticancer activity. Overall, these findings suggest that antiretroviral, especially protease inhibitors, may cause anticancer effects, although these are concentration- and context-dependent, and further investigation is needed to understand the mechanisms involved. Full article

The coronavirus (COVID-19) pandemic necessitated unprecedented regulatory responses that enabled rapid therapeutic deployment. The integrated medico-legal framework—comprising the FD&C Act Section 564 (Emergency Use Authorization/EUA), PREP Act (liability immunity), and CICP (injury compensation)—facilitated emergency response while protecting all stakeholders. This normative legal and policy analysis examines nirmatrelvir/ritonavir (Paxlovid) as a case study, integrating emerging pharmacokinetic evidence demonstrating its passage across the blood–brain and blood–placenta barriers. The EUA-PREP-CICP framework achieved notable results: nirmatrelvir/ritonavir’s authorization enabled deployment approximately 1 year after trials began, demonstrating an 89% reduction in the risk of hospitalization or death and potentially preventing thousands of hospitalizations. The PREP Act enabled focused pharmaceutical development and protected frontline healthcare workers during the crisis, though access barriers and transparency concerns remain areas warranting ongoing attention. The CICP provided administrative compensation for qualifying injuries, with acknowledged limitations in filing timelines and causation standards. Pharmacokinetic studies published after authorization revealed biological barrier crossing, representing normal scientific progress through continued investigation. The EUA-PREP-CICP nexus functioned as an integrated system: EUA enabled rapid evidence-based access, PREP immunity facilitated development and deployment, and CICP provided injury remedy. Based on this experience, this study proposes targeted enhancements to further strengthen this framework: systematic post-authorization surveillance timelines, enhanced special population monitoring through registries, modest procedural refinements to CICP, and improved surveillance infrastructure. These evidence-based improvements would build on the framework’s demonstrated strengths, optimizing performance for future emergencies while preserving the essential functions that helped address the COVID-19 pandemic. Full article

Although ombitasvir/paritaprevir/ritonavir plus dasabuvir (OPrD) therapy is highly effective for chronic hepatitis C (CHC), clinicians frequently encounter transient hyperbilirubinemia, which can be misidentified as hepatotoxicity. This study investigated the role of SLCO1B1 (OATP1B1) and SLCO1B3 (OATP1B3) genetic polymorphisms in predicting bilirubin spikes and distinguishing transporter-mediated interference from hepatocellular injury. In this prospective study of 65 patients with HCV genotype 1, genotyping for OATP1B1 (c.388A>G, c.521T>C) and OATP1B3 (c.334T>G, c.699G>A) was performed using PCR-RFLP and capillary electrophoresis (QIAxcel Advanced System). Clinical and biochemical parameters were monitored over a 12-week treatment period. Hyperbilirubinemia (total bilirubin >1.1 mg/dL) developed in 18.5% of the cohort, typically within the first month. A distinct ‘AST-dominant’ biochemical signature, elevated bilirubin and AST paired with stable ALT, was identified, suggesting transporter-specific interference rather than hepatocyte damage. Statistical analysis pinpointed the OATP1B3 c.699G>A (rs7311358) variant as the sole genetic driver (p = 0.007). Carriers of the c.699G>A allele faced a 6.3-fold higher risk of developing hyperbilirubinemia (OR: 6.30, 95% CI: 1.48–26.80, p = 0.032), while no significant associations were found for OATP1B1 variants. We conclude that OATP1B3 c.699G>A is a potent predictor of OPrD-induced hyperbilirubinemia. Identifying this genotype pre-treatment allows clinicians to anticipate transient, benign bilirubin elevations and prevent unnecessary drug discontinuation, thereby mitigating therapeutic inertia and ensuring treatment continuity for CHC patients. Full article

Objectives: The co-administration of Bruton’s tyrosine kinase (BTK) inhibitors with antiretroviral drugs is challenging due to potential drug–drug interactions (DDIs). However, clinical trials specifically assessing such DDIs are lacking. We aimed to evaluate DDIs between the BTK inhibitors ibrutinib, zanubrutinib and acalabrutinib with representative antiretroviral drugs and to provide dose adjustment strategies using physiologically based pharmacokinetic (PBPK) models. Methods: PBPK models were developed in PK-Sim software. Model performance was verified by comparing simulated pharmacokinetic parameters and DDI magnitudes with probe drugs (midazolam or maraviroc) with reported clinical data. The validated models were subsequently applied to assess DDIs and explore dose adjustment strategies. Results: The developed PBPK model accurately describes the pharmacokinetics of each drug. Darunavir/ritonavir substantially increased the maximum plasma concentration (C_max) of ibrutinib, zanubrutinib, and acalabrutinib by 496%, 312%, and 160%, respectively. In contrast, efavirenz reduced C_max by 43%, 33%, and 37%, respectively, while etravirine caused smaller decreases of 5%, 0%, and 10%. Based on these predictions, recommended dose adjustment strategies include ibrutinib 105 mg once daily, zanubrutinib 40 mg twice daily, and acalabrutinib 50 mg twice daily when co-administered with darunavir/ritonavir or ibrutinib 980 mg once daily, zanubrutinib 240 mg twice daily, and acalabrutinib 150 mg twice daily when co-administered with efavirenz. No dose adjustment is required with etravirine. Conclusions: The PBPK models accurately predicted the in vivo pharmacokinetics of ibrutinib, zanubrutinib, acalabrutinib, and those of the antiretrovirals darunavir/ritonavir, efavirenz, and etravirine, and the DDIs between them. The dose adjustment strategies provided information valuable to the optimization of antineoplastic therapy in HIV-related lymphoma (HRL) patients. Full article

Background: Ribociclib, initially approved for HR+/HER2− advanced breast cancer (ABC) at a 600 mg dose, was recently approved for HR+/HER2− early breast cancer (EBC) at a 400 mg dose based on the NATALEE trial. Differences in dose and patient population warrant reassessment of ribociclib drug–drug interactions (DDIs) and the impact of hepatic or renal impairment (HI/RI) in EBC patients to guide co-medication management and subpopulation dose recommendations. Methods: Physiologically-based pharmacokinetic (PBPK) modeling based on a healthy volunteer population was conducted to assess ribociclib DDIs with CYP3A4 substrates/modulators in patients with EBC. Subgroup analysis from NATALEE assessed HI/RI impact on ribociclib PK in EBC patients. Existing data from ABC/advanced cancer patients and non-cancer subjects were also integrated to inform dose recommendations for EBC subpopulations. Results: PBPK modeling predicted that ritonavir or erythromycin (strong and moderate CYP3A4 inhibitors) would increase ribociclib steady-state area under the concentration–time curve (AUC) by 1.84-fold or show no meaningful impact, respectively. Steady-state ribociclib AUC was estimated to decrease by 83% and 74% with rifampicin and efavirenz, strong and moderate CYP3A4 inducers, respectively. Ribociclib was estimated to increase CYP3A4 substrate midazolam exposure by 280%. Mild HI or mild/moderate RI did not show an apparent impact on ribociclib PK. Conclusions: Using relevant data and methodology for EBC patients, this analysis informed the approved ribociclib label of no dose adjustment for EBC patients with concomitant use of a moderate CYP3A inhibitor, any degree of HI, or mild/moderate RI, and a reduced 200 mg dose for patients with concomitant use of a strong CYP3A inhibitor or severe RI. Full article

Early in 2020, the WHO recommended that existing drugs be evaluated as a repurposed resource to fight the SARS-CoV-2 pandemic. Here, we investigate the trends of using repurposed and off-label drugs among people living with HIV in Central and Eastern Europe (CEE). From November 2020 to May 2021, data on the clinical outcomes of HIV-positive patients diagnosed with COVID-19 were collected on eCRFs (SurveyMonkey^® platform, Inc. San Mateo, CA, USA). Factors associated with the off-label drugs available at this time (chloroquine, hydroxychloroquine, favipiravir, oseltamivir, and lopinavir/ritonavir) were identified using logistic regression models. Of the 557 HIV-positive patients assessed with COVID-19 disease, 67 (12.0%) received off-label drugs, as well as 11.6% (16/138) of hospitalized and 12.2% (51/419) of ambulatory patients (p = 0.8564). In the adjusted logistic regression model, higher odds of off-label drug use were found in patients who had their diagnoses confirmed by an RT PCR test (aOR 5.08 [95%CI 1.17–22.0], p = 0.0396), and who came from a non-EU region (aOR 6.79 [95%CI 3.51–13.1], p < 0.0001). The only factor decreasing the odds of off-label drug use was co-infection (aOR 0.31 [95%CI 0.10–0.94], p < 0.0395). In a cohort of HIV patients from the CEE, 12% were prescribed off-label drugs for COVID-19. Symptomatic patients with confirmed SARS-CoV-2 infection or who were from non-EU countries were more likely to receive a repurposed drug. Drug repurposing is an immediate solution to emerging pandemics. All data regarding the safety and effectiveness of such use should be monitored, reported, and publicly available. Access patterns within and outside the EU should be analyzed to prevent potential inequalities in access to care during epidemics in European settings. Full article

Antiviral substances are considered emerging contaminants. Once released into the environment, they may affect organisms through complex and often still-unknown mechanisms. This study focuses on a class of antiviral substances with potential use in treating COVID-19 patients, aiming to identify specific structural characteristics that significantly contribute to their ecotoxicity. An empirical approach called quantitative structure–activity relationship (QSAR) was used for this purpose. The study examined 13 antiviral substances: atazanavir, daclatasvir, darunavir, emtricitabine, favipiravir, lopinavir, nirmatrelvir, oseltamivir, remdesivir, ribavirin, ritonavir, and sofosbuvir. The ecotoxicity of these antivirals was assessed using three tests: the Aliivibrio fischeri test, the Chlorella sp. test, and the Pseudomonas putida test. These three microorganisms represent different trophic levels in aquatic and soil ecosystems. Ecotoxicity was expressed as EC₂₀ and EC₅₀, and these values served as the dependent variables in the QSAR models. A large set of numerical descriptors calculated from the molecular structures of the antivirals was used as an independent variable. EC₂₀-based QSAR models offer insight into the effects of antivirals under sub-lethal exposure conditions. The results indicated that sub-lethal exposure in Aliivibrio fischeri was associated with favorable electronic properties and compact structures that promote cellular accumulation, while long-range fragments reduced toxicity. In Chlorella sp., sub-lethal exposure was driven by optimal molecular size, chain length, and specific electronic groups enabling cell penetration and biochemical inhibition. For sub-lethal exposure in P. putida, lipophilicity and reactive group geometry enhanced toxicity, while high short-range polarity mitigated it by limiting membrane permeability. Acute toxicity patterns showed similar trade-offs: strong electronic reactivity increased potency, but steric bulk, long-range polarity, or unfavorable mass distribution frequently restricted bioavailability and reduced toxic effects. Overall, the models demonstrated that antiviral toxicity results from a balance of electronic activity, structural accessibility, and physicochemical constraints, providing a mechanistic basis for predicting the environmental risk of selected antiviral substances. Full article

Drug- and alcohol-induced liver injury involves impaired bile acids or bilirubin secretion, but it is not known how senescence influences the secretion of hepatocytes exposed to drugs and alcohol. In this study, the toxic effects of ritonavir, lopinavir, and alcohol on hepatocyte transporters and the secretion of bile acids and bilirubin were investigated in hydrogen peroxide-induced senescent HepG2 and doxorubicin-induced senescent primary human hepatocytes. In HepG2, intracellular conjugated bilirubin increased upon senescence and extracellular conjugated bilirubin in culture medium was decreased by ritonavir and lopinavir treatment. In the primary hepatocytes, intracellular bile acids or medium bilirubin were not significantly changed upon senescence. However, intracellular bile acids were increased, and medium conjugated bilirubin were decreased in senescent primary hepatocytes treated with alcohol and the two drugs. Transcriptional expressions of adenosine triphosphate (ATP)-binding cassette (ABC) transporters (ABCB4, ABCC6, ABCB11, and ABCD3) were decreased whereas UDP-glucuronosyltransferase (UGT1A1) was increased by ritonavir and lopinavir in senescent HepG2. In senescent primary hepatocytes, expressions of ABCB11, ABCC1, ABCC2, ABCC3, ABCC4, and ABCC6 were apparently reduced whereas UGT1A1 and the cytochrome P450 enzyme CYP7A1 were markedly increased by alcohol combined with ritonavir and lopinavir. Selective ABCC6 knockdown in the primary hepatocytes altered expressions of two senescence markers, Lamin A/C and cyclin-dependent kinase inhibitor CKI (p21), increased expressions of CYP7A1 and hydroxy methyl glutaryl-CoA reductase (HMGCR), and increased intracellular bile acids. Further, anti-cholestasis agents, ursodeoxycholic acid and glycyrrhizin, significantly ameliorated the impaired secretions of bile acids and bilirubin as well as reducing intracellular lipid accumulation and cell death caused by ritonavir, lopinavir, and alcohol in the primary hepatocytes with ABCC6 knockdown. These results indicate that senescence moderately impairs the ABC transporters of hepatocytes and secretion of bile acids or bilirubin, which become worse in the presence of the drugs and alcohol but could be improved by anti-cholestasis agents. Full article

The extensive use of antiviral substances (SASs) during and after the COVID-19 pandemic has increased their release into wastewater systems, raising concerns regarding their persistence and potential ecotoxicological effects. The primary objective of this study was to isolate bacterial strains from activated sludge (AS) that possess the ability to biodegrade SASs. From the AS sample, three bacterial species, Comamonas testosteroni (I2), Bacillus amyloliquefaciens (I3) and Bacillus mycoides (I4), were successfully isolated and identified. These strains were subsequently applied in biodegradation experiments targeting seven SASs: daclatasvir (DCV), darunavir (DRV), favipiravir (FAV), lopinavir (LOP), remdesivir (REM), ritonavir (RIT), and umifenovir (UMI). During the experiments, residual SAS concentrations, microbial growth parameters, physicochemical indicators and ecotoxicity were monitored. All three strains demonstrated substantial biodegradation potential, achieving reductions exceeding 90% for most tested compounds, with particularly low toxicity observed in experiments conducted with AS and Bacillus amyloliquefaciens. These findings highlight the relevance of AS-derived bacteria as promising candidates for enhancing SAS removal in wastewater treatment processes. Full article

Organic anion-transporting polypeptides (OATPs) are key transporters of hepatic uptake for endogenous compounds and xenobiotics. Human OATP1B1 and OATP1B3 are well-studied due to their role in drug–drug interactions. In contrast, data on murine OATP1B2, the rodent orthologue of these transporters, are limited, despite its importance in early drug development. Here, we systematically compared the transport characteristics of mouse and rat OATP1B2 under identical experimental conditions. The K_m values for estrone-3-sulfate (E₁S) and taurocholate (TCA) were 242 and 73 µM for mOATP1B2 and 90 and 16 µM for rOATP1B2. Nine clinically relevant drugs were evaluated for inhibitory effects, showing strong correlation between species. Cyclosporine A, ritonavir, odevixibat, rosuvastatin, and rifampicin markedly inhibited uptake. Rifampicin demonstrated species-specific differences, with higher IC₅₀ values for mOATP1B2 (E₁S: 9.6 µM; TCA: 7.7 µM) than rOATP1B2 (E₁S: 1.1 µM; TCA: 2.4 µM). A comparison of the rodent data with the human orthologues revealed similar inhibition patterns but distinct substrate selectivity: hOATP1B1 showed high affinity for E₁S but negligible TCA uptake, while hOATP1B3 transported TCA weakly but not E₁S. This study provides insights into species-specific differences in OATP-mediated hepatic uptake and is therefore valuable for the interpretation of preclinical studies and their transfer to human pharmacology. Full article

Background: Immunocompromised patients, particularly those with humoral immune deficiencies or receiving B-cell-targeted therapies, are at increased risk of persistent SARS-CoV-2 infection, a condition often underrecognized and lacking standardized treatment. Methods: We present a case series of patients with persistent SARS-CoV-2 infection and underlying humoral immunodeficiency, treated at the General University Hospital “Attikon” from February 2023 to September 2024. Persistent infection was defined by prolonged symptoms, compatible imaging findings, and RT-PCR positivity beyond 21 days. All patients received combination antiviral therapy with remdesivir and nirmatrelvir/ritonavir, and intravenous immunoglobulin (IVIG), using a structured diagnostic and therapeutic algorithm. Results: Eleven patients (55% male), median age 56 [IQR 50–66] years, were included. Seven (64%) had hematologic malignancy, 10 (91%) received anti-CD20 therapy, and 6 (55%) had both. Median symptom duration before diagnosis was 63 [58–135] days. Ten (91%) experienced recurrent symptoms; one (9%) had progressive symptoms with severe respiratory failure requiring high-flow nasal cannula. Persistent infection was confirmed via bronchoscopy with bronchoalveolar lavage in 6 patients (55%). Prior to diagnosis, 5 patients (45%) required one hospitalization, 1 (9%) was hospitalized twice, and 2 (18%) had more than two hospitalizations. Following combination therapy, 10 (91%) achieved complete response at 180-day follow-up. Conclusions: The proposed diagnostic and therapeutic algorithm combining remdesivir, nirmatrelvir/ritonavir, and IVIG enhanced diagnostic value and therapeutic outcomes in this high-risk population. Full article

Ritonavir (RTV), an effective aspartyl protease inhibitor, was originally developed to counter the replication of human immune deficiency virus and then employed as a pharmacokinetic enhancer in antiretroviral therapy. Yet unexpectedly, RTV exerted antitumor effects that added to its antiviral action, as it impacted the migration, invasion, oxidative stress, and proteasome function of human tumor cells. More recently, RTV was shown to directly inhibit DNA repair enzymes, thereby enhancing radiosensitivity and synergizing with chemotherapeutics across multiple cancer models. However, RTV induced oxidative stress and DNA damage also in non-tumor cells, including the reproductive ones. This duality highlights both the possibility of RTV anticancer use and the concern for its safety. In this Perspective, we propose the repurposing of RTV as a novel tool to potentiate DNA-damage-based antitumor therapies such as radiotherapy and/or chemotherapy. At the same time, we underscore the need for a careful assessment of RTV side effects. Full article

Background/Objectives: Molnupiravir (MOV) and nirmatrelvir (NMV) are antiviral drugs that were FDA-approved under the emergency use authorization (EUA) for coronavirus disease-2019 (COVID-19) treatment. MOV and NMV target the viral RNA-dependent RNA polymerase and main protease, respectively. Paxlovid is a combination of NMV and ritonavir (RTV), an inhibitor of the human cytochrome P450-3A4 (hCYP3A4). In this study, the structural consequences in the hCYP3A4 caused by MOV-induced mutations (MIM) were evaluated using in silico tools. Methods: MOV-induced mutations (MIM) were inserted into all the possible hotspots in the active site region of the hCYP3A4 gene, and mutant protein models were built. Structural changes in the heme-porphyrin ring of hCYP3A4 were analyzed in the presence and absence of substrates/inhibitors, including RTV. Molecular dynamics (MD) simulations were performed to analyze the effect of MIM-induced structural changes in hCYP3A4 on drug binding. Results: MD simulations confirm that MIMs, R375G and R440G in hCYP3A4 severely affect the heme-porphyrin ring stability by causing a tilt that in turn affects RTV binding, suggesting a possible inefficiency in the function of hCYP3A4. Similar results were seen for amlodipine, atorvastatin, sildenafil and warfarin, which are substrates of hCYP3A4. Conclusions: The current in silico studies indicate that hCYP3A4 containing MIMs can create complications in the treatment of COVID-19 patients, particularly with co-morbidities due to its functional inefficiency. Hence, clinicians must be vigilant when using MOV in combination with other drugs. Further in vitro studies focused on hCYP3A4 containing MIMs are currently in progress to support our current in silico findings. Full article

Background: Medication safety in pregnancy, puerperium, and perinatal periods is underexplored because these populations are excluded from clinical trials. EudraVigilance offers post-marketing evidence, but disproportionality analyses focus on isolated drug event pairs and may miss syndromic patterns. We applied a network- and cluster-based framework to EudraVigilance reports on antiviral use in pregnancy to improve surveillance and identify meaningful constellations. Methods: We retrieved all individual case safety reports (ICSRs) from January 2015 to June 2025, including pregnancy, puerperium, or perinatal terms, focusing on suspect antivirals. After parsing terms, disproportionality metrics were computed as a benchmark. A bipartite drug–event network was built and projected to event–event co-occurrence networks; Louvain community detection identified clusters. Clusters were characterized by size, drug mix, seriousness, overlap with disproportionality signals, and stratification across periods. Results: The dataset comprised 106,924 ICSRs and 232,067 unique pairs. Disproportionality yielded 6142 signals, mainly involving antiretrovirals (ritonavir, lamivudine, zidovudine, emtricitabine/tenofovir). Network analysis revealed clusters grouping maternal and fetal/neonatal outcomes (e.g., fetal death, low birth weight), and transplacental transfer, highlighting structures not visible in pairwise analyses. Several clusters combined high-frequency exposures with clinically relevant outcomes, suggesting early-warning potential. Conclusions: Combining disproportionality with network- and cluster-based pharmacovigilance adds value for monitoring pregnancy medication safety. Beyond individual signals, this approach reveals meaningful clusters and “bridge” reactions connecting adverse-event domains, offering a richer framework for perinatal surveillance. Despite spontaneous-reporting limits, findings generate hypotheses for mechanistic and pharmacoepidemiologic follow-up and support network methods as complements to traditional pharmacovigilance. Full article