CYP3A4 Inhibitor Research Articles

Pharmacokinetics (PK) and pharmacogenomics (PGx) of ribociclib (ribo) in Black patients with metastatic breast cancer (mBC): The LEANORA study.

1581 Background: Ribo is metabolized by CYP3A and used for the treatment of patients with hormone receptor-positive (HR+)/HER2- mBC. FDA recommends dose reduction if used with CYP3A inhibitors due to a 3.2x increase ribo area-under-the-curve (AUC). It is unknown if modifications are needed in patients who lack enzyme activity (e.g., genetic CYP3A5 poor metabolizers (PM)). CYP3A5varies by genetic ancestry, is known to affect dosing for other drugs (e.g., tacrolimus). CYP3A5, ~85% of people of European ancestry are PM, ~85% of African ancestry are normal or intermediate metabolizers (NM, IM), which may impact ribo exposure and response. 2 percent (41/2066) enrolled in MONALEESA 2, 3, and 7 were Black. Methods: This prospective, multicenter cohort study (NCT04657679) assessed the PK and PGx of ribo (600 mg daily + letrozole/fulvestrant) in self-identified Black women with HR+/HER2- mBC. PK (0.5, 1, 2, 4, and 6 hours after ribo) and PGx studies were performed during cycle 1 via liquid chromatography with tandem mass spectrometry and PharmacoScan (ThermoFisher) microarray, which tests 1,191 genes. Including variants in CYP3A5*3, *6,and *7. Phenotypes assigned: PM (2 variant alleles), intermediate metabolism (IM; 1 variant allele), NM (0 variant alleles). The area under the curve (AUCtau) was compared with the exact Wilcoxon rank-sum test; Fisher’s exact test assessed the AEs and grade 3+ AEs to day 28. Results: 14 completed the trial. CYP3A5 phenotypes were PM (7), IM (6), and NM (1). The primary endpoint, AUCtau, was similar between CYP3A5 PM (39,230 hr*ng/mL; interquartile range [IQR]: 18,745 to 57,566 hr*ng/mL) vs. IM/NM (43,546 hr*ng/mL; IQR: 35,298 to 46,647 hr*ng/mL; p = 0.38). Other PK properties were similar between groups (table). There was a non-statistically significant higher number of AEs and grade 3+ AEs in PMs, when compared to NM/IMs. Study was not powered to assess differences in AEs. Conclusions: This cohort study detected no association between CYP3A5 genotype and ribo exposure. However, PMs may have more AEs relative to IMs/NMs. Future steps include exploring the impact of rare variants, including ~70 variants in CYP3A 4 and 5, on ribo exposure in this population. We will explore the role of clinical and genetic factors on the interindividual variability of ribo. Diverse patient representation in clinical trials is critical to ensure research findings are applicable to all patients. Clinical trial information: NCT04657679 .[Table: see text]

A first-in-human, phase 1, dose escalation study of SGR-2921 as monotherapy in patients with relapsed/refractory acute myeloid leukemia or myelodysplastic syndrome.

TPS6590 Background: Cell division cycle 7-related protein kinase (CDC7) is a cell cycle kinase that maintains DNA replication by phosphorylation and activation of the minichromosome maintenance protein 2 and 4 (MCMs), components of the replicative DNA helicase. Due to the CDC7's central role in maintaining replication fork integrity, chemical inhibition of CDC7 can ultimately lead to cancer cell death. SGR-2921 is an oral, small molecule inhibitor of CDC7. Preclinical studies demonstrate that SGR-2921 has potent anti-proliferative activity in AML cell lines representative of difficult to treat patient populations, agnostic of serious mutations (including those with p53 mutations), BTK resistance, and multiple prior lines of treatment. This anti-tumor activity has also been demonstrated in cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) AML models. Methods: This is a phase 1, FIH, open-label, single-agent, two-arm, dose escalation study (NCT#05961839) designed to evaluate safety and tolerability and identify the recommended phase 2 dose (RP2D) of SGR-2921 as monotherapy in subjects with relapsed or refractory (R/R) AML, high risk (HR) MDS, or very high risk (VHR) MDS. The study utilizes an accelerated titration design with single patient cohorts that transitions to a 3+3 design once a single Grade 2 event is observed. This is a multicenter global study (US, Spain and France). SGR-2921 will be administered orally, once daily, utilizing a 5-day on and 9-day off dosing schedule over a 28-day cycle. A maximum of 144 patients will be enrolled into dose escalation and exploratory cohorts. To evaluate the effect of CYP3A4 inhibition on SGR-2921 exposure, subjects will be enrolled into one of two staggered, parallel study treatment arms, according to concomitant administration with (Arm B) or without (Arm A) azole antifungals that are strong CYP3A4 inhibitors. A single dose PK run-in will be required for subjects enrolled into the first 3 cohorts of each treatment arm. Subjects will be treated at increasing doses of SGR-2921 until the maximum tolerated dose (MTD) is exceeded. A RP2D will be selected from one of the tolerable dose levels. Key study inclusion criteria include: Age ≥ 18 years of age; Life expectancy ≥ 8 weeks; Confirmed diagnosis of R/R AML or HR and VHR MDS; Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2. Key study exclusion criteria include: Active malignancies not related to AML or MDS within two years prior to the first dose or requiring ongoing treatment; active CNS leukemia; QTcF ≥470 msec. The primary objectives are to evaluate the safety and tolerability of SGR-2921 as monotherapy and to identify the RP2D. Secondary objectives include evaluating SGR-2921 pharmacokinetics and investigating preliminary antitumor activity. Clinical trial information: NCT05961839 .

Covalent-103: A phase 1, open-label, dose-escalation and expansion study of BMF-500, an oral covalent FLT3 inhibitor, in adults with acute leukemia (AL).

TPS6589 Background: FLT3 mutations occur in 25-35% of AML and result from an internal tandem duplication (ITD) of amino acids in the juxtamembrane domain of FLT3 kinase or point mutations in the tyrosine kinase domain (TKD). FLT3-ITD mutations are associated with increased relapse, shorter remission, and decreased disease-free and overall survival. BMF-500 is a novel oral, highly potent and selective covalent inhibitor of FLT3 including wild-type (WT), ITD, TKD, and resistance mutations (e.g., gatekeeper F691). BMF-500 has high affinity for FLT3, lack of cKIT inhibition, and sustained cell-killing despite drug washout (Law et al., ASH 2022 Abst 2756). BMF-500 shows sustained tumor regression and improved survival in subcutaneous and disseminated xenografts of FLT3-m AML. Methods: COVALENT-103 (NCT05918692) is a multicenter, first-in-human study evaluating the safety, tolerability, and antileukemic activity of escalating doses of daily BMF-500 in patients with relapsed or refractory (R/R) AL, including AML, ALL, or MPAL, with or without FLT3-m. The trial has 2 arms that dose escalate in parallel: Arm A (without) and Arm B (with) concomitant use of a CYP3A4 inhibitor. Using an accelerated titration design (ATD), doses of BMF-500 are escalated in single-subject cohorts until one subject experiences ≥Grade 2 related adverse event or dose-limiting toxicity (DLT). At that point, the cohort will switch to a classical “3 +3” design. Patients with WT FLT3 AL may enroll up to 33% per arm. Treatment continues in 28-day cycles until progression or intolerability. Expansion cohorts will enroll additional patients to obtain further safety and efficacy data. Patients must be refractory, relapsed or have progressed on or following discontinuation of the most recent anti-cancer therapy or be ineligible for any approved standard of care, including hematopoietic stem cell transplant (HSCT). FLT3-positive AML patients must have received a FLT3 inhibitor approved for R/R FLT3-m AML. Additional inclusion criteria include ECOG PS ≤2, adequate organ function, and documented FLT3 mutation status. Key exclusion criteria include known CNS disease, clinically significant cardiovascular disease, and WBC >50,000/µL (uncontrollable with cytoreductive therapy). The primary objective is to evaluate safety and tolerability and determine the optimal biological dose (OBD)/ recommended Phase 2 dose (RP2D) of BMF-500 monotherapy based on available pharmacokinetic/pharmacodynamic (PK/PD), safety and efficacy data. Secondary objectives include characterization of the PK/PD of BMF-500, and assessment of its antitumor activity per modified Cheson (2003) criteria or NCCN Clinical Practice Guidelines (ALL Version 1.2022) as determined by the investigator. The study was initiated in July 2023, is currently in dose escalation, and we plan to enroll approximately 110 patients total. Clinical trial information: NCT05918692 .

Peak study: A phase 3, randomized, open-label multi-center clinical study of bezuclastinib (CGT9486) and sunitinib combination versus sunitinib in patients with gastrointestinal stromal tumors (GIST).

TPS11588 Background: Imatinib is the worldwide standard for first-line therapy of advanced KIT-mutant GIST. However, secondary resistance mutations in the KIT ATP-binding domain (exons 13, 14), activation loop (exons 17, 18), or both develop and result in loss of imatinib-sensitivity. Bezuclastinib has a highly selective inhibition profile, leading to minimal off-target toxicities and allowing for combination with sunitinib. While no single tyrosine kinase inhibitor (TKI) inhibits all KIT mutations, the combination of bezuclastinib + sunitinib targets commonly occurring primary (exons 9, 11) and secondary (exons 13, 14, 17, and 18) KIT mutations and may provide more durable responses. The early signs of clinical activity, tolerability, and safety observed with the combination thus far in Peak Part 1 (Somaiah et al. [presentation] CTOS 2023. Paper 62) are consistent with the completed Phase 1/2 study (PLX121-01). Methods: Peak (NCT05208047) is a global, randomized, open-label, multi-part Phase 3 study evaluating the efficacy and safety of bezuclastinib + sunitinib versus sunitinib as second-line treatment in adult pts who were intolerant to imatinib or whose tumors had imatinib-resistance. Current Peak study sites are located in North America (3 countries), South America (3 countries), Europe (12 countries), and Asia-Pacific (4 countries). The lead-in portion to test a new formulation of bezuclastinib, (Part 1) completed enrollment in April 2023. Based upon PK and safety, a dose of bezuclastinib 600 mg QD + sunitinib 37.5 mg QD was determined for Part 2 of the Peak study. Part 2 will enroll ~388 pts to be randomized (1:1) to bezuclastinib 600 mg QD + sunitinib 37.5 mg QD or sunitinib 37.5 mg QD alone. Key inclusion: >1 measurable lesion per modified Response Evaluation Criteria in Solid Tumors (mRECIST) v1.1, Eastern Cooperative Oncology Group Performance Status 0-2, adequate organ function, and prior imatinib therapy (no other prior therapy). Key exclusion: known PDGFR mutations or succinate dehydrogenase deficiency, clinically significant cardiac disease, and use of strong CYP3A4 inhibitors or inducers. The primary endpoint is progression-free survival (PFS) confirmed by blinded independent central review per mRECIST v1.1. Additional efficacy (including overall survival and objective response rate) and safety endpoints will be evaluated and circulating tumor DNA (ctDNA) will be collected and assessed. Clinical trial information: NCT05208047 .

Tipifarnib physiologically-based pharmacokinetic modeling to assess drug-drug interaction, organ impairment, and biopharmaceutics in healthy subjects and cancer patients.

A physiologically-based pharmacokinetic (PBPK) model for tipifarnib, which included mechanistic absorption, was built and verified by integrating invitro data and several clinical data in healthy subjects and cancer patients. The final PBPK model was able to recover the clinically observed single and multiple-dose plasma concentrations of tipifarnib in healthy subjects and cancer patients under several dosing conditions, such as co-administration with a strong CYP3A4 inhibitor and inducer, an acid-reducing agent (proton pump inhibitor and H2 receptor antagonist), and with a high-fat meal. In addition, the model was able to accurately predict the effect of mild or moderate hepatic impairment on tipifarnib exposure. The appropriately verified model was applied to prospectively simulate the liability of tipifarnib as a victim of CYP3A4 enzyme-based drug-drug interactions (DDIs) with a moderate inhibitor and inducer as well as tipifarnib as a perpetrator of DDIs with sensitive substrates of CYP3A4, CYP2B6, CYP2D6, CYP2C9, and CYP2C19 in healthy subjects and cancer patients. The effect of a high-fat meal, acid-reducing agent, and formulation change at the therapeutic dose was simulated. Finally, the model was used to predict the effect of mild, moderate, or severe hepatic, and renal impairment on tipifarnib PK. This multipronged approach of combining the available clinical data with PBPK modeling-guided dosing recommendations for tipifarnib under several conditions. This example showcases the totality of the data approach to gain a more thorough understanding of clinical pharmacology and biopharmaceutic properties of oncology drugs in development.

In Vitro Investigations into the Potential Drug Interactions of Pseudoginsenoside DQ Mediated by Cytochrome P450 and Human Drug Transporters.

Pseudoginsenoside DQ (PDQ), an ocotillol-type ginsenoside, is synthesized with protopanaxadiol through oxidative cyclization. PDQ exhibits good anti-arrhythmia activity. However, the inhibitory effect of PDQ on the cytochrome 450 (CYP450) enzymes and major drug transporters is still unclear. Inhibition of CYP450 and drug transporters may affect the efficacy of the drugs being used together with PDQ. These potential drug-drug interactions (DDIs) are essential for the clinical usage of drugs. In this study, we investigated the inhibitory effect of PDQ on seven CYP450 enzymes and seven drug transporters with in vitro models. PDQ has a significant inhibitory effect on CYP2C19 and P-glycoprotein (P-gp) with a half-inhibitory concentration (IC50) of 0.698 and 0.41 μM, respectively. The inhibition of CYP3A4 and breast cancer-resistant protein (BCRP) is less potent, with IC50 equal to 2.02-6.79 and 1.08 μM, respectively.

Identification of an Epoxide Metabolite of Amitriptyline In Vitro and In Vivo.

Amitriptyline (ATL), a tricyclic antidepressant, has been reported to cause various adverse effects, particularly hepatotoxicity. The mechanisms of ATL-induced hepatotoxicity remain unknown. The study was performed to identify the olefin epoxidation metabolite of ATL and determine the possible toxicity mechanism. Two glutathione (GSH) conjugates (M1 and M2) and two N-acetylcysteine (NAC) conjugates (M3 and M4) were detected in rat liver microsomal incubations supplemented with GSH and NAC, respectively. Moreover, M1/M2 and M3/M4 were respectively found in ATL-treated rat primary hepatocytes and in bile and urine of rats given ATL. Recombinant P450 enzyme incubations demonstrated that CYP3A4 was the primary enzyme involved in the olefin epoxidation of ATL. Treatment of hepatocytes with ATL resulted in significant cell death. Inhibition of CYP3A attenuated the susceptibility to the observed cytotoxicity of ATL. The metabolic activation of ATL most likely participates in the cytotoxicity of ATL.

Xin-yi-san contains potent human CYP1A2 inhibitors and its combined use with theophylline in treatment increases adverse risks in patients

BackgroundThe Xin-yi-san herbal decoction (XYS) is commonly used to treat patients with allergic rhinitis in Taiwan. Theophylline is primarily oxidized with high affinity by human cytochrome P450 (CYP)1A2, and has a narrow therapeutic index. PurposeThis study aimed to investigate the inhibition of human CYP1A2-catalyzed theophylline oxidation (THO) by XYS and its adverse effects in patients. MethodsHuman CYPs were studied in recombinant enzyme systems. The influence of concurrent XYS usage in theophylline-treated patients was retrospectively analyzed. ResultsAmong the major human hepatic and respiratory CYPs, XYS inhibitors preferentially inhibited CYP1A2 activity, which determined the elimination and side effects of theophylline. Among the herbal components of XYS decoction, Angelicae Dahuricae Radix contained potent THO inhibitors. Furanocoumarin imperatorin was abundant in XYS and Angelicae Dahuricae Radix decoctions, and non-competitively inhibited THO activity with Ki values of 77‒84 nM, higher than those (20‒52 nM) of fluvoxamine, which clinically interacted with theophylline. Compared with imperatorin, the intestinal bacterial metabolite xanthotoxol caused weaker THO inhibition. Consistent with the potency of the inhibitory effects, the docking analysis generated Gold fitness values in the order−fluvoxamine > imperatorin > xanthotoxol. During 2017‒2018, 2.6 % of 201,093 theophylline users consumed XYS. After inverse probability weighting, XYS users had a higher occurrence of undesired effects than non-XYS users; in particular, there was an approximately two-fold higher occurrence of headaches (odds ratio (OR), 2.14; 95 % confidence interval (CI), 1.99‒2.30; p < 0.001) and tachycardia (OR, 1.83; 95 % CI, 1.21‒2.77; p < 0.05). The incidence of irregular heartbeats increased (OR, 1.36; 95 % CI, 1.07‒1.72; p < 0.05) only in the theophylline users who took a high cumulative dose (≥ 24 g) of XYS. However, the mortality in theophylline users concurrently taking XYS was lower than that in non-XYS users (OR, 0.24; 95 % CI, 0.14‒0.40; p < 0.001). ConclusionXYS contains human CYP1A2 inhibitors, and undesirable effects were observed in patients receiving both theophylline and XYS. Further human studies are essential to reduce mortality and to adjust the dosage of theophylline in XYS users.

Phase 1 drug-drug interaction study to assess the effect of CYP3A4 inhibition and pan-CYP induction on the pharmacokinetics and safety of fosmanogepix in healthy participants.

This study is registered with ClinicalTrials.gov as NCT04166669 and with EudraCT as number 2019-003586-17.

Examining dietary supplements containing Euterpe oleracea Mart. (açaí) for potential botanical-drug interactions involving CYP3A4 inhibition

BackgroundBotanical dietary supplements (BDS) are consumed more by cancer patients than otherwise healthier patients to alleviate side effects of chemotherapy drugs or increase quality of life. The enzyme responsible for the metabolism of most anticancer drugs is CYP3A4, an enzyme predominantly located in the liver. HypothesisOur research team examined the potential risk between CYP3A4-interactive cancer drugs and Euterpe oleracea Mart. (açaí) berry and found that the compounds that passively and non-passively diffused from methanol açaí extract displayed significant inhibition of liver CYP3A4 – suggesting the potential for interactions between açaí and drugs metabolized by CYP3A4 if used synchronously. This study aims to identify the compounds responsible for the CYP3A4 inhibition using the newly automated Bioactivity – Global Natural Product Social Molecular Networking (GNPS) tool. MethodsDietary supplement capsules from two manufacturers (F1 and F2) containing aqueous extracts of açaí fruits were extracted separately by methanol (ME) and acidic methanol (AC) and standardized to cyanidin-3-O-glucoside (CG) concentration at a human-relevant dose. After solvent removal, a parallel artificial membrane permeability assay (PAMPA) was utilized to filter intestinal passive diffusion of the four extract constituents so that compounds could be tested for inhibition of hepatic CYP3A4. Passively and non-passively diffused constituents of extracts from PAMPA assays were injected into the liquid chromatography-mass spectrometry (LC–MS) and characterized for visualization and comparison of chemical entities. To elucidate the non-passively diffused compounds responsible for significant CYP3A4 inhibition, the Bioactivity – GNPS tool was used to hypothesize which compounds within the formulation extract were potentially active to accelerate their identification. ResultsThere was no significant inhibition of CYP3A4 by passively diffused constituents for any extract. There was, however, significant inhibition by non-passively diffused constituents of both F1ME and F1AC extracts with 50 % CYP3A4 inhibition at the donor compartment concentrations 5.764 and 15.58 ng/ml CG, respectively. Six compounds were predicted to be inhibitors of CYP3A4 from methanol F1 extract, including betaine and 5 unknown compounds. ConclusionThis indicates that BDS containing açaí may not inhibit CYP3A4 through passively diffused compounds. Compounds from açaí BDS that inhibit CYP3A4 may be absorbed through other mechanisms, such as transporters.

Evaluating Drug Interactions between Ritonavir and Opioid Analgesics: Implications from Physiologically Based Pharmacokinetic Simulation.

Several commonly used opioid analgesics, such as fentanyl, sufentanil, alfentanil, and hydrocodone, are by report primarily metabolized by the CYP3A4 enzyme. The concurrent use of ritonavir, a potent CYP3A4 inhibitor, can lead to significant drug interactions. Using physiologically based pharmacokinetic (PBPK) modeling and simulation, this study examines the effects of different dosing regimens of ritonavir on the pharmacokinetics of these opioids. The findings reveal that co-administration of ritonavir significantly increases the exposure of fentanyl analogs, with over a 10-fold increase in the exposure of alfentanil and sufentanil when given with ritonavir. Conversely, the effect of ritonavir on fentanyl exposure is modest, likely due to additional metabolism pathways. Additionally, the study demonstrates that the steady-state exposure of hydrocodone and its active metabolite hydromorphone can be increased by up to 87% and 95%, respectively, with concurrent use of ritonavir. The extended-release formulation of hydrocodone is particularly affected. These insights from PBPK modeling provide valuable guidance for optimizing opioid dosing and minimizing the risk of toxicity when used in combination with ritonavir-containing prescriptions.

Design, synthesis, molecular modeling, in vitro and in vivo biological evaluation of potent anthranilamide derivatives as dual P-glycoprotein and CYP3A4 inhibitors

Paclitaxel (PTX) is considered the blockbuster chemotherapy treatment for cancer. Paclitaxel's (PTX) oral administration has proven to be extremely difficult, mostly because of its susceptibility to intestinal P-glycoprotein (P-gp) and cytochrome P450 (CYP3A4). The concurrent local inhibition of intestinal P-gp and CYP3A4 is a promising approach to improve the oral bioavailability of paclitaxel while avoiding potential unfavorable side effects of their systemic inhibition. Herein, we report the rational design and evaluation of novel dual potent inhibitors of P-gp and CYP3A4 using an anthranilamide derivative tariquidar as a starting point for their structural optimizations. Compound 14f, bearing N-imidazolylbenzyl side chain, was found to have potent and selective P-gp (EC50 = 28 nM) and CYP3A4 (IC50 = 223 nM) inhibitory activities with low absorption potential (Papp (A-to-B) <0.06). In vivo, inhibitor 14f improved the oral absorption of paclitaxel by 6 times in mice and by 30 times in rats as compared to vehicle, while 14f itself remained poorly absorbed. Compound 14f, possessing dual P-gp and CYP3A4 inhibitory activities, offered additional enhancement in paclitaxel oral absorption compared to tariquidar in mice. Evaluating the CYP effect of 14f on oral absorption of paclitaxel requires considering the variations in CYP expression between animal species. This study provides further medicinal chemistry advice on strategies for resolving concerns with the oral administration of chemotherapeutic agents.

Drug-Cannabinoid Interactions in Selected Therapeutics for Symptoms Associated with Epilepsy, Autism Spectrum Disorder, Cancer, Multiple Sclerosis, and Pain.

Clinical practice entails a translation of research that assists in the use of scientific data and therapeutic evidence for the benefit of the patient. This review critically summarizes the potential impact of cannabinoids in conjunction with other drugs when associated with treatments for epilepsy, autism spectrum disorder, cancer, multiple sclerosis, and chronic pain. In these associations, potential drug interactions may occur and alter the predicted clinical results. Therefore, the potential for drug interactions must always be assessed to avoid therapeutic failures and/or increased side effects. Some effects may be additive, synergistic, or antagonistic, but changes in absorption, distribution, metabolism, particularly through cytochrome P450 (CYP) isoenzymes (e.g., CYP2C9 and CYP3A4), and excretion may also occur. For example, the combination of cannabis-derived compounds and the antifungal drug ketoconazole, a CYP3A4 inhibitor, increases the plasma concentration of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). In contrast, rifampicin, a CYP3A4 inducer, stands out for reducing plasma THC levels by approximately 20-40% and 50% to 60% for CBD. Other CYP3A4 inhibitors and inducers are likely to have a similar effect on plasma concentrations if co-administered. Pharmacokinetic interactions with anticonvulsant medications have also been reported, as have pharmacodynamic interactions between cannabinoids and medications with sympathomimetic effects (e.g., tachycardia, hypertension), central nervous system depressants (e.g., drowsiness, ataxia), and anticholinergics (e.g., tachycardia and somnolence). Although further studies are still pending, there is currently clinical evidence supporting drug interactions with cannabinoids, requiring doctors to evaluate the risk of drug combinations with cannabinoids and vice versa. The tables provided here were designed to facilitate the identification of biorelevant interactions that may compromise therapeutic efficacy and toxicity.

Lack of CYP3A4 protein induction despite mRNA induction in primary hepatocytes exposed to rifabutin as a possible explanation for its low interaction risk in vivo.

Rifampicin is a strong inducer of cytochrome P450 (CYP3A4) and P-glycoprotein (P-gp/ABCB1), leading to profound drug-drug interactions. In contrast, the chemically related rifabutin does not show such pronounced induction properties in vivo. The aim of our study was to conduct a comprehensive analysis of the different induction potentials of rifampicin and rifabutin in primary human hepatocytes and to analyze the mechanism of potential differences. Therefore, we evaluated CYP3A4/ABCB1 mRNA expression (polymerase chain reaction), CYP3A4/P-gp protein expression (immunoaffinity-liquid chromatography-mass spectrometry, IA-LC-MS/MS), CYP3A4 activity (testosterone hydroxylation), and considered intracellular drug uptake after treatment with increasing rifamycin concentrations (0.01-10µM). Furthermore, rifamycin effects on the protein levels of CYP2C8, CYP2C9, and CYP2C19 were analyzed (IA-LC-MS/MS). Mechanistic analysis included the evaluation of possible suicide CYP3A4 inhibition (IC50 shift assay) and drug impact on translational efficiency (cell-free luminescence assays). Rifabutin accumulated 6- to 15-fold higher in hepatocytes than rifampicin, but induced CYP3A4 mRNA comparably to rifampicin (e. g. rifampicin 61-fold vs. rifabutin 44-fold, 72h). While rifampicin for example enhanced protein (10µM: 21-fold) and activity levels considerably (53-fold), rifabutin only slightly increased CYP3A4 protein expression (10µM: 3.3-fold) or activity (11-fold) compared to rifampicin after 72h. Both rifamycins similarly influenced expression of other eliminating proteins. A potential CYP3A4 suicide inhibition by a specific rifabutin metabolite or disruption of ribosome function were excluded experimentally. In conclusion, the lack of protein enhancement, could explain rifabutin's weaker induction-related drug-drug interaction risk in vivo.

Comparison of the CYP3A Selective Inhibitors CYP3cide, Clobetasol, and Azamulin for Their Potential to Distinguish CYP3A7 Activity in the Presence of CYP3A4/5.

The CYP3A7 enzyme accounts for ∼50% of the total cytochrome P450 (P450) content in fetal and neonatal livers and is the predominant P450 involved in neonatal xenobiotic metabolism. Additionally, it is a key player in healthy birth outcomes through the oxidation of dehydroepiandrosterone (DHEA) and DHEA-sulfate. The amount of the other hepatic CYP3A isoforms, CYP3A4 and CYP3A5, expressed in neonates is low but highly variable, and therefore the activity of individual CYP3A isoforms is difficult to differentiate due to their functional similarities. Consequently, a better understanding of the contribution of CYP3A7 to drug metabolism is essential to identify the risk that drugs may pose to neonates and developing infants. To distinguish CYP3A7 activity from CYP3A4/5, we sought to further characterize the selectivity of the specific CYP3A inhibitors CYP3cide, clobetasol, and azamulin. We used three substrate probes, dibenzylfluorescein, luciferin-PPXE, and midazolam, to determine the IC50 and metabolism-dependent inhibition (MDI) properties of the CYP3A inhibitors. Probe selection had a significant effect on the IC50 values and P450 inactivation across all inhibitory compounds and enzymes. CYP3cide and azamulin were both identified as MDIs and were most specific for CYP3A4. Contrary to previous reports, we found that clobetasol propionate (CP) was not an MDI of CYP3A5 but was more selective for CYP3A5 over CYP3A4/7. We further investigated CYP3cide and CP's ability to differentiate CYP3A7 activity in an equal mixture of recombinant CYP3A4, CYP3A5, and CYP3A7, and our results provide confidence of CYP3cide's and CP's ability to distinguish CYP3A7 activity in the presence of the other CYP3A isoforms. SIGNIFICANCE STATEMENT: These findings provide valuable insight regarding in vitro testing conditions to investigate the metabolism of new drug candidates and help determine drug safety in neonates. The results presented here also clearly demonstrate the effect that probe selection may have on CYP3A cytochrome P450 inhibition studies.

A physiologically-based pharmacokinetic precision dosing approach to manage dasatinib drug-drug interactions.

Dasatinib, a second-generation tyrosine kinase inhibitor, is approved for treating chronic myeloid and acute lymphoblastic leukemia. As a sensitive cytochrome P450 (CYP) 3A4 substrate and weak base with strong pH-sensitive solubility, dasatinib is susceptible to enzyme-mediated drug-drug interactions (DDIs) with CYP3A4 perpetrators and pH-dependent DDIs with acid-reducing agents. This work aimed to develop a whole-body physiologically-based pharmacokinetic (PBPK) model of dasatinib to describe and predict enzyme-mediated and pH-dependent DDIs, to evaluate the impact of strong and moderate CYP3A4 inhibitors and inducers on dasatinib exposure and to support optimized dasatinib dosing. Overall, 63 plasma profiles from perorally administered dasatinib in healthy volunteers and cancer patients were used for model development. The model accurately described and predicted plasma profiles with geometric mean fold errors (GMFEs) for area under the concentration-time curve from the first to the last timepoint of measurement (AUClast) and maximum plasma concentration (Cmax) of 1.27 and 1.29, respectively. Regarding the DDI studies used for model development, all (8/8) predicted AUClast and Cmax ratios were within twofold of observed ratios. Application of the PBPK model for dose adaptations within various DDIs revealed dasatinib dose reductions of 50%-80% for strong and 0%-70% for moderate CYP3A4 inhibitors and a 2.3-3.1-fold increase of the daily dasatinib dose for CYP3A4 inducers to match the exposure of dasatinib administered alone. The developed model can be further employed to personalize dasatinib therapy, thereby help coping with clinical challenges resulting from DDIs and patient-related factors, such as elevated gastric pH.

Discovery of a Novel and Potent Cyclin-Dependent Kinase 8/19 (CDK8/19) Inhibitor for the Treatment of Cancer.

The mediator kinases CDK8 and CDK19 control the dynamic transcription of selected genes in response to various signals and have been shown to be hijacked to sustain hyperproliferation by various solid and liquid tumors. CDK8/19 is emerging as a promising anticancer therapeutic target. Here, we report the discovery of compound 12, a novel small molecule CDK8/19 inhibitor. This molecule demonstrated not only decent enzymatic and cellular activities but also remarkable selectivity in CDK and kinome panels. Besides, compound 12 also displayed favorable ADME profiles including low CYP1A2 inhibition, acceptable clearance, and high oral bioavailability in multiple preclinical species. Robust in vivo PD and efficacy studies in mice models further demonstrated its potential use as mono- and combination therapy for the treatment of cancers.

Molecular Docking and Pharmacokinetic Studies of Moringa oleifera As Angiotensin-Converting Enzyme Inhibitors

Background: Hypertension in pregnancy is a vascular disorder that occurs before pregnancy or arises during pregnancy that there were 30% of cases of maternal death. Moringa oleifera's potential to lower blood pressure can be utilized as an alternative antihypertensive during pregnancy, minimizing the risk of preeclampsia. Objective: The purpose of this study was to determine the molecular target of Moringa oleifera is intended to optimize pharmacodynamic activity based on the interaction pattern of the compounds with the ACE inhibitor (PDB ID: 1O86). Methods: Molecular docking is carried out using Autodock 4.0 program (AutoDock Tools). Results: According to the binding energy value and ACE inhibitory interaction, a-Rhamnopyranosyl, b-Sitosterol, and Sinalbin are prospective Moringa oleifera compounds as alternative antihypertensive. These potential compounds can inhibit ACE with binding energy -8.23; -9.27; -9.14 kcal/mol. Pharmacokinetic predictions reported that the potential compounds are absorbed in the intestine and indicates as molecules are tightly bound to plasma proteins and, as well as CYP3A4 and CYP2C9 inhibitors. The prediction of toxicity indicates that the potential compounds are classified as drug-induced acute liver failure with low carcinogens. Conclusion: a-Rhamnopyranosyl, b-Sitosterol and Sinalbin can be suitable lead compounds for synthetic drugs for antihypertensive agents.

Pharmacokinetic study of capivasertib and the CYP3A4 substrate midazolam in patients with advanced solid tumors

PurposeCapivasertib, a potent, selective inhibitor of all three AKT serine/threonine kinase (AKT) isoforms, is being evaluated in phase 3 trials in advanced breast and prostate cancer. This study evaluated the drug–drug interaction risk of capivasertib with the cytochrome P450 3A substrate midazolam in previously treated adults with advanced solid tumors.MethodsPatients received oral capivasertib 400 mg twice daily (BID) on an intermittent schedule (4 days on/3 days off) starting on day 2 of cycle 1 (29 days) and on day 1 of each 28-day cycle thereafter. In cycle 1 only, patients received oral midazolam (1 mg) on day 1 (alone), and days 8 and 12 (3rd day off and 4th day on capivasertib, respectively). Midazolam pharmacokinetics on days 8 and 12 were analyzed versus day 1. Capivasertib, with or without standard-of-care treatment, was continued in patients deemed likely to benefit. Safety and exploratory efficacy analyses were conducted.ResultsCapivasertib–midazolam coadministration increased midazolam exposure (n = 21): geometric mean ratio (90% confidence interval) AUCinf and Cmax was 1.13 (0.97–1.32) and 1.15 (0.99–1.33) for day 8 versus day 1, and 1.75 (1.50–2.05) and 1.25 (1.08–1.46) for day 12 versus day 1. The capivasertib safety profile was manageable when administered with or without midazolam. Two patients had partial responses to treatment.ConclusionThe up to 1.75-fold increase in midazolam exposure indicates capivasertib is a weak CYP3A inhibitor at 400 mg BID on an intermittent schedule. Capivasertib was well tolerated; exploratory efficacy analysis demonstrated evidence of clinical activity in this heavily pre-treated population.ClinicalTrials.gov: NCT04958226.

Pharmacokinetic analysis of antiviral drug ritonavir across the blood–brain barrier and its interaction with Scutellaria baicalensis using multisite microdialysis in rats

Ritonavir, an excellent inhibitor of CYP3A4, has recently been combined with nirmatrelvir to form Paxlovid for the treatment of severe acute respiratory syndrome coronavirus 2 infections. The root of Scutellaria baicalensis Georgi (S. baicalensis), a traditional Chinese medicinal (TCM) herb commonly used to treat heat/inflammation in the lung and digestive tracts, which are major organs targeted by viral infections, contains flavones that can influence the CYP3A metabolism pathway. To investigate the ability of ritonavir to cross the bloodbrain barrier (BBB) and its potential herb-drug interactions with an equivalent TCM clinical dose of S. baicalensis, multisite microdialysis coupled with an LCMS/MS system was developed using rat model. Pretreatment with S. baicalensis extract for 5 days, which contains less flavones than those used in previous studies, had a significant influence on ritonavir, resulting in a 2-fold increase in the total concentration of flavones in the blood and brain. Treatment also boosted the maximum blood concentration of flavones by 1.5-fold and the maximum brain concentration of flavones by 2-fold, all the while exerting no noticeable influence on the transfer ratio across the bloodbrain barrier. These experimental results demonstrated that the use of a typical traditional Chinese medicinal dose of S. baicalensis is sufficient to influence the metabolic pathway and synergistically increase the concentration of ritonavir in rats.