Potential Pharmacokinetic Drug-drug Interactions Research Articles

Antiviral Use in Mild-to-Moderate SARS-CoV-2 Infections during the Omicron Wave in Geriatric Patients.

(1) Background: Geriatric patients are at high risk of complications of Coronavirus disease-2019 (COVID-19) and are good candidates for antiviral drugs. (2) Methods: A retrospective study of electronic health records (EHRs) aiming to describe antiviral (nirmatrelvir and ritonavir (nirmatrelvir/r) or remdesivir) use, drug-drug interactions (DDIs) and adverse drug reactions (ADRs) in elderly patients (75 and over), hospitalized with mild-to-moderate COVID-19 between July 2022 and June 2023. (3) Results: Out of 491 patients (mean age: 86.9 years), 180 (36.7%) received nirmatrelvir/r, 78 (15.9%) received remdesivir, and 233 (47.4%) received no antiviral therapy. No association was found between the choice of antiviral and the demographic or medical data. No serious ADR was observed. Nirmatrelvir/r dosage adjustment was inadequate in 65% of patients with renal impairment. In total, 128 patients (71%) on nirmatrelvir/r had potential pharmacokinetic DDIs, with 43 resulting in a possibly related ADR. In the remdesivir group, pharmacodynamic DDIs were more frequent, with QTc prolongation risk in 56 patients (72%). Only 20 patients underwent follow-up ECG, revealing QTc prolongation in 4. (4) Conclusions: There is an underutilization of antivirals despite their justified indications. Nirmatrelvir/r dosage was rarely adjusted to renal function. Dose adjustments and closer monitoring are needed due to the high risk of drug interactions.

Interactions médicamenteuses de type pharmacocinétique avec les inhibiteurs d’ALK: Pharmacokinetic drug-drug interactions with ALK inhibitors

The ALK inhibitors exhibit an inter-patient variability in clinical response (efficacy, toxicity). The pharmacokinetic variability is one of the factors contributing to this clinical variability. Patients treated with ALK inhibitors are candidates to drug-drug interaction since they are commonly polymedicated for the treatment of their comorbidities, pain and/or adverses events related to the antitumor treatment. Given ALK inhibitors exhibit a narrow therapeutic index, some pharmacokinetic drug-drug interactions can therefore result either in supra-therapeutic plasma concentrations raising the toxic risk or in infra-therapeutic concentrations leading to decreased efficacy. Besides, food or phytotherapy can also significantly altered the pharmacokinetics of some ALK inhibitors. This review focuses on the potential pharmacokinetic drug-drug interactions with ALK inhibitors.1877-1203/© 2023 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Iatrogenic Side Effects of Pain Therapies.

Pain regimens, particularly for chronic cancer and noncancer pain, must balance the important analgesic benefits against potential risks. Many effective and frequently used pain control regimens are associated with iatrogenic adverse events. Interventional procedures can be associated with nerve injuries, vascular injuries, trauma to the spinal cord, and epidural abscesses. Although rare, these adverse events are potentially catastrophic. Pharmacologic remedies for pain must also consider potential side effects that can occur even at therapeutic doses of over-the-counter remedies such as paracetamol (acetaminophen) or nonsteroidal anti-inflammatory drugs. Opioids are effective pain relievers but are associated with many side effects, some of which can be treatment limiting. A prevalent and distressing side effect of opioid therapy is constipation. Opioid-induced constipation is caused by binding to opioid receptors in the gastrointestinal system, making conventional laxatives ineffective. Peripherally acting mu-opioid receptor antagonists are a new drug class that offers the benefits of preserving opioid analgesia without side effects in the gastrointestinal system. An important safety concern, particularly among geriatric patients is the increasingly prevalent condition of polypharmacy. Many senior patients take five or more medications, including some that may be contraindicated in geriatric patients, duplicative of other drugs, have potential pharmacokinetic drug-drug interactions, or may not be the optimal choice for the patient's age and condition. Careful assessment of medications in the elderly, including possibly deprescribing with tapering of certain drugs, may be warranted but should be done systematically and under clinical supervision.

Pharmacokinetic interaction of voriconazole and clarithromycin in Pakistani healthy male volunteers: a single dose, randomized, crossover, open-label study.

Background: Voriconazole an antifungal drug, has a potential for drug-drug interactions (DDIs) with administered drugs. Clarithromycin is a Cytochromes P450 CYP (3A4 and 2C19) enzyme inhibitor, and voriconazole is a substrate and inhibitor of these two enzymes. Being a substrate of the same enzyme for metabolism and transport, the chemical nature and pKa of both interacting drugs make these drugs better candidates for potential pharmacokinetic drug-drug interactions (PK-DDIs). This study aimed to evaluate the effect of clarithromycin on the pharmacokinetic profile of voriconazole in healthy volunteers. Methods: A single oral dose, open-label, randomized, crossover study was designed for assessing PK-DDI in healthy volunteers, consisting of 2weeks washout period. Voriconazole, either alone (2mg × 200mg, tablet, P/O) or along with clarithromycin (voriconazole 2mg × 200mg, tablet + clarithromycin 500mg, tablet, P/O), was administered to enrolled volunteers in two sequences. The blood samples (approximately 3 cc) were collected from volunteers for up to 24h. Plasma concentrations of voriconazole were analyzed by an isocratic, reversed-phase high-performance-liquid chromatography ultraviolet-visible detector (RP HPLC UV-Vis) and a non-compartmental method. Results: In the present study, when voriconazole was administered with clarithromycin versus administered alone, a significant increase in peak plasma concentration (Cmax) of voriconazole by 52% (geometric mean ratio GMR: 1.52; 90% CI 1.04, 1.55; p = 0.000) was observed. Similarly, the area under the curve from time zero to infinity (AUC0-∞) and the area under the concentration-time curve from time zero to time-t (AUC0-t) of voriconazole also significantly increased by 21% (GMR: 1.14; 90% CI 9.09, 10.02; p = 0.013), and 16% (GMR: 1.15; 90% CI 8.08, 10.02; p = 0.007), respectively. In addition, the results also showed a reduction in the apparent volume of distribution (Vd) by 23% (GMR: 0.76; 90% CI 5.00, 6.20; p = 0.051), and apparent clearance (CL) by 13% (GMR: 0.87; 90% CI 41.95, 45.73; p = 0.019) of voriconazole. Conclusion: The alterations in PK parameters of voriconazole after concomitant administration of clarithromycin are of clinical significance. Therefore, adjustments in dosage regimens are warranted. In addition, extreme caution and therapeutic drug monitoring are necessary while co-prescribing both drugs. Clinical Trial Registration: clinicalTrials.gov, Identifier NCT05380245.

Prevalence of polypharmacy and risk of potential drug-drug interactions among hospitalized patients with emphasis on the pharmacokinetics.

Both polypharmacy and potential drug-drug interactions (pDDIs), especially those at the pharmacokinetic level, are common in hospitalized patients and are associated with adverse effects and failure of therapy. The aim of the present study is to investigate retrospectively the prevalence of polypharmacy and the risk of potential pharmacokinetic drug-drug interaction among hospitalized patients. The medical documentation of hospitalized patients in the unit of internal diseases at the hospital "St Marina" in Varna, Bulgaria for a period of six months (January-July 2016) was retrospectively reviewed. Lexicomp® Drug Interaction software was used for the detection of pDDI. Descriptive statistic and logistic regression were used for data analysis. In this study, 294 patients out of 510 (57%) were selected with polypharmacy. The number of detected potential pharmacokinetic DDIs (pPKDDIs) was only 216 (or 12,4%), but almost 40% of patients with polypharmacy were exposed to at least one pPKDDIs. The most common pPKDDIs occur at the biotransformation level - 78 (36,1%), and the most common enzyme form that is involved in these interactions is cytochrome 3A4 (44 or 20,4%). The number of prescribed medications (>7) was found to increase the possibility of having pDDIs (OR 25.535, 95% CI 12.529 to 52.042; p = <0.001) and pPKDDIs (OR 5.165, 95% CI 3.430 to 7.779; p = <0.001) as well. Caution should be taken in patients taking more than seven drugs and careful assessment of the pPKDDIs should be made. When such interactions are detected, they need to be properly evaluated and managed.

The bioequivalence of fixed-dose combination tablets of bisoprolol and ramipril and its drug-drug interaction potential.

Chronic antihypertensive treatment often includes combination of two or more therapies with complementary mechanism of action targeting different blood pressure (BP) control system. If available, these components are recommended to be administered as a fixed‐dose combination (FDC) to reduce tablet burden, improve adherence and thus BP control. A combination of ramipril (RAMI) and bisoprolol (BISO) is one of the options used in clinical practice and is supported by therapeutic guidelines. The clinical program for a novel BISO/RAMI FDC consisted of two randomized, open‐label, bioequivalence (BE) studies and one drug‐drug interaction (DDI) study. The BE was examined between two FDC strengths of BISO/RAMI (10/10 and 10/5 mg) and the individual reference products administered concomitantly at respective doses after a single oral dose under fasting conditions. In both BE studies, 64 healthy subjects were randomized according to a two‐way crossover design. The DDI study evaluated a potential pharmacokinetic (PK) interaction between BISO 10 mg and RAMI 10 mg following their single or concomitant administrations in 30 healthy subjects under fasting condition. BE for BISO/RAMI 10/5 mg and absence of a clinically relevant PK DDI between BISO and RAMI was demonstrated as the 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) for area under the concentration time curve (AUC) and maximum concentration (Cmax) remained within the acceptance range of 80.00 to 125.00%. However, BE for BISO/RAMI 10/10 mg was not demonstrated, as the lower bound of the 90% CI of Cmax for RAMI was outside the acceptance range of BE. Both drugs administered alone or combined were well‐tolerated. No PK interaction was observed between BISO and RAMI/ramiprilat, since the co‐administration of BISO and RAMI 10 mg single doses resulted in comparable rate and extent of absorption for BISO and RAMI when compared to their individual products.

Prevalence and Significance of Potential Pharmacokinetic Drug-Drug Interactions Among Patients with Lung Cancer: Implications for Clinical Trials.

The overall prevalence of potential drug-drug interactions (DDIs) among patients with lung cancer is unknown. The objective of this study was to determine the prevalence of potential DDIs and major DDIs among individuals newly diagnosed with lung cancer in a national cohort. We performed a retrospective cross-sectional study of adult patients in the United States Veterans' Affairs (VA) medical system diagnosed with lung cancer between 2003 and 2016. The primary endpoint was the prevalence of prescriptions for medications associated with any potential DDIs during the 3months leading up to and including the date of lung cancer diagnosis. The secondary endpoint was the prevalence of prescriptions associated with major DDIs during the same time period. Overall, 280,068 patients were included in the study; 55.9% of patients were prescribed medications associated with potential DDIs, while 5.3% received prescriptions for medications associated with major DDIs. Among the 20 most commonly prescribed drugs associated with potential DDIs, only two were associated with major DDIs. Medications with potential DDIs are prescribed to the majority of patients with lung cancer; however, only about 5% of patients are prescribed medications with major DDIs that might be prohibited in certain clinical trials.

Potential Pharmacokinetic Drug-Drug Interactions between Cannabinoids and Drugs Used for Chronic Pain.

Choosing an appropriate treatment for chronic pain remains problematic, and despite the available medication for its treatment, still, many patients complain about pain and appeal to the use of cannabis derivatives for pain control. However, few data have been provided to clinicians about the pharmacokinetic drug-drug interactions of cannabinoids with other concomitant administered medications. Therefore, the aim of this brief review is to assess the interactions between cannabinoids and pain medication through drug transporters (ATP-binding cassette superfamily members) and/or metabolizing enzymes (cytochromes P450 and glucuronyl transferases).

Emerging Use of Epidiolex (Cannabidiol) in Epilepsy

The first plant-derived, purified pharmaceutical-grade cannabidiol (CBD) medication, Epidiolex, was approved in the United States by the FDA on June 25, 2018. Its approval for patients ≥ 2 years of age with Dravet syndrome (DS) or Lennox-Gastaut syndrome (LGS) markedly altered the treatment of medically refractory seizures in these disorders. This state-of-the-art review will discuss the history of CBD, its current pharmacology and toxicology, evidence supporting its use in a variety of epileptic syndromes, common side effects and adverse effects, and pharmacokinetically based drug-drug interactions. Owing to the importance in considering side effects, adverse effects, and drug-drug interactions in patients with medically refractory epilepsy syndromes, this review will take a deeper look into the nuances of the above within a clinical context, as compared to the other antiepileptic medications. Furthermore, despite the limited data regarding clinically significant drug-drug interactions, potential pharmacokinetic drug-drug interactions with CBD and other antiepileptics are theorized on the basis of their metabolic pathways. The article will further elucidate future research in terms of long-term efficacy, safety, and drug interactions that is critical to addressing unanswered questions relevant to clinical practice.

Association between clinically relevant toxicities of pazopanib and sunitinib and the use of weak CYP3A4 and P-gp inhibitors.

Sunitinib and pazopanib, two tyrosine kinase inhibitors (TKI), may be targets of potential pharmacokinetic drug-drug interactions (P-PK-DDIs). While strong cytochrome P4503A (CYP3A4) inhibitors or inducers should cause a clinically relevant modification in plasma TKI concentrations, the effect of weak inhibitors is unknown. The objective of this study was to evaluate the association between weak P-PK-DDI and clinically relevant toxicity in real life. This was a single-center retrospective study including patients treated with sunitinib or pazopanib for any malignancies, for whom a PK-DDI analysis was performed before starting TKI. The primary endpoint was the correlation between P-PK-DDIs and a dose decrease after 1month of treatment. The secondary endpoint was the correlation between PK-DDIs and drug withdrawal due to toxicity. Seventy-six patients were assessed. A P-PK-DDI with weak CYP3A4 or P-gp inhibition was found in 14 patients. In patients with P-PK-DDI or without, the dose was reduced during the first month in 57.1% and 17.7% (p = 0.003) and the drug withdrawn in 42.8% and 11.3% (p = 0.011), respectively. In multivariate analysis, a significant correlation was found between P-PK-DDI (CYP3A4 and P-gp inhibitors) and dose reduction, and between drug withdrawal and PK-DDI (CYP3A4 inhibitors). P-PK-DDI was correlated with dose reduction and drug withdrawal due to toxicity. The causality of this relationship warrants to be assessed; therefore, therapeutic drug monitoring is necessary in patients treated with TKI.

Abstract 3895: A phase I-II pharmacokinetic drug-drug interaction evaluation of oral palbociclib in combination with vemurafenib in patients suffering metastatic melanoma with BRAF V600 mutated and CDKN2A loss &amp; expression of Rb

Abstract Background: A novel combination of vemurafenib (VM), a selectif inhibitor of BRAF V600 mutated protein + oral palbociclib (Palbo) a highly selective reversible oral inhibitor of cyclin-dependent kinases (CDK) 4 and 6, could provide a synergistic antitumor activity in patients with metastatic melanoma harbouring BRAF V600 mutation and CDKN2A loss. VM has been shown to be an inductor of CYP3A4 which is also mainly involved in Palbo metabolism. In this study we investigated the potential pharmacokinetic (PK) drug-drug interactions (DDI) related to the association of VM and Palbo. Methods: metastatic melanoma harbouring BRAF V600 mutation and CDKN2A loss patients were treated with a 14 days on followed by 7 days off dosing schedule of Palbo + continuous bid dosing of VM. Dose levels [DL, Palbo (mg/day)/VM (mg/bid)] ranged from 25/720 to 200/960. For PK analysis, 7 time point samples were collected on D1C1, D21C1, and D7C2, for Palbo and VM assays. Plasma concentrations of Palbo and VM, were measured using ultra high performance liquid chromatography (UHPLC) coupled with tandem mass spectrometry validated methods. Population PK (PPK) was modeled using a non linear mixed effect model program (Monolix version 2018r) by computing the maximum likelihood estimator of the parameters without any approximation of the model (no linearization). The following parameters were calculated absorption constant (Ka); apparent distribution volume (V/F); apparent clearance (CL/F) Results: A total of 18 patients were treated by the combination of Palbo + VM. VM and palbo plasma concentrations were measured in 236 and 275 blood samples respectively. A one-compartment open model with linear elimination adequately described Palbo concentration-time courses. The inter-individual variabilities (ISV) could be well estimated for all stuctural parameters. The PPK parameters obtained for the structural model were: Ka = 0.791 h-1, CL/F=76.0L/h, V1/F=2830 L. Albuminemia had a significant impact on palbo CL. A one-compartment model adequately fitted the VM plasma concentration-time data. The PPK parameters were CL/F=0.133 L/h, V/F=83.6 L and Ka has been fixed at 0.2 h-1. Body weight (BW) was the best size descriptor when VM CL and V terms were normalized to a mean BW of 70 Kg according to an allometric scaling rule. Conclusions: The PPK modeling satisfactorily described the plasma Plabo and VM time-concentration curves in patients. The main covariate effect was related to BW and albuminemia. There is no significant evidence for drug-drug PK interaction between Palbo and VM. PK-PD modeling will be performed. Citation Format: Samuel Huguet, Thierry Lesimple, Arthur Geraud, Mouna Amini-Adle, Caroline Dutriaux, Laetitia Da Meda, Florence Capelle, Zineb Ghrieb, Samia Mourah, Olivier Madar, Didier Bouton, Mathieu Resche-Rigon, Celest Lebbe, Keyvan Rezai. A phase I-II pharmacokinetic drug-drug interaction evaluation of oral palbociclib in combination with vemurafenib in patients suffering metastatic melanoma with BRAF V600 mutated and CDKN2A loss &amp; expression of Rb [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3895.

Potential drug-drug interactions with direct oral anticoagulants in elderly hospitalized patients.

To determine the prevalence and nature of potential drug-drug interactions (DDIs) with direct oral anticoagulants (DOACs) in elderly hospitalized patients. This was a retrospective observational study. Inclusion criteria were: aged over 65 years; taking apixaban, rivaroxaban or dabigatran; and admitted to the Repatriation General Hospital between April 2014 and July 2015. A list of clinically relevant 'perpetrator' drugs was compiled from product information, the Australian Medicines Handbook, the Australian National Prescribing Service resources, and local health network guidelines. The prevalence and nature of potential DDIs with DOACs was determined by comparing inpatient drug charts with the list of perpetrator drugs. There were 122 patients in the study with a mean age of 82 years. Most patients had nonvalvular atrial fibrillation and were taking DOACs to prevent thrombotic stroke (83%). Overall, 45 patients (37%) had a total of 54 potential DDIs. Thirty-five patients had potential pharmacodynamic DDIs with antidepressants, nonsteroidal anti-inflammatory drugs and antiplatelets (35/122, 29%). Nineteen patients had potential pharmacokinetic DDIs (19/122, 16%). Of these, 68% (13/19) were taking drugs that increase DOAC plasma concentrations (amiodarone, erythromycin, diltiazem or verapamil) and 32% (6/19) were taking drugs that decrease DOAC plasma concentrations (carbamazepine, primidone or phenytoin). There were no cases of patients taking contraindicated interacting drugs. Potential DDIs with DOACs in elderly hospital inpatients are relatively common, particularly interactions that may increase the risk of bleeding. The risk-benefit ratio of DOACs in elderly patients on polypharmacy should always be carefully considered.

Drug-drug interactions between immunosuppressants and antidiabetic drugs in the treatment of post-transplant diabetes mellitus.

Post-transplant diabetes mellitus is a frequent complication of solid organ transplantation that generally requires treatment with lifestyle interventions and antidiabetic medication. A number of demonstrated and potential pharmacokinetic drug-drug interactions (DDIs) exist between commonly used immunosuppressants and antidiabetic drugs, which are comprehensively summarized in this review. Cyclosporine (CsA) itself inhibits the cytochrome P450 (CYP) 3A4 enzyme and a variety of drug transporters. As a result, it increases exposure to repaglinide and sitagliptin, will likely increase the exposure to nateglinide, glyburide, saxagliptin, vildagliptin and alogliptin, and could theoretically increase the exposure to gliquidone and several sodium-glucose transporter (SGLT)-2 inhibitors. Currently available data, although limited, suggest that these increases are modest and, particularly with regard to gliptins and SGLT-2 inhibitors, unlikely to result in hypoglycemia. The interaction with repaglinide is more pronounced but does not preclude concomitant use if repaglinide dose is gradually titrated. Mycophenolate mofetil and azathioprine do not engage in DDIs with any antidiabetic drug. Although calcineurin inhibitors (CNIs) and mammalian target of rapamycin inhibitors (mTORi) are intrinsically prone to DDIs, their disposition is not influenced by metformin, pioglitazone, sulfonylureas (except possibly glyburide) or insulin. An effect of gliptins on the disposition of CNIs and mTORi is unlikely, but has not been definitively ruled out. Based on their disposition profiles, glyburide and canagliflozin could affect CNI and mTORi disposition although this requires further study. Finally, delayed gastric emptying as a result of glucagon-like peptide-1 agonists seems to have a limited, but not necessarily negligible effect on CNI disposition.

Abstract 2049: Pharmacokinetic drug-drug interaction: a phase Ib dose escalation study of LY2780301 in combination with weekly paclitaxel

Abstract Introduction: LY2780301 is an orally available small molecule dual inhibitor of p70 S6 kinase and AKT. LY2780301 is an inhibitor of CYP3A4. By the one hand, Paclitaxel (PXL) undergoes extensive metabolism via CYP450 2C8 and CYP450 3A4 pathways. By the other hand, PXL induces weakly CYP3A4 activity. In this study we investigated for the first time, the potential pharmacokinetic (PK) drug-drug interaction (DDI) related to the combination of both drugs LY2780301 and PXL. Methods: Women with HER2- locally advanced or metastatic breast cancer, with and without PI3/AKT pathway activation, were treated with weekly administration of PXL on day1 (D1), D8 and D15. LY2780301 was administered by a daily flat dosing regimen starting at D3. Dose levels [DL, LY2780301 (mg/day)/PXL (mg/m2/week)] ranged from 400/70 to 500/80. For PK analysis, 7 time point samples were collected on D1 and D3 of cycle 1 for PXL and LY2780301 respectively. 7 samples were collected on D8 for both drugs. LY2780301 plasma concentrations were measured using Ultra Performance Liquid Chromatography (UPLC) coupled with tandem mass spectrometry validated method. PXL plasma concentrations were measured using UPLC coupled with UV validated method. A joint population PK (PK-POP) model has been developed for LY2780301 and its main metabolite. PK-POP modelling has been performed with a non linear mixed effect model program (Monolix version 4.3.2). Results: 12 patients, 35 to 67 years old, were treated. A total of 160 and 157 concentrations for LY2780301 and its metabolite were used respectively for PK-POP modeling. A one compartment open model adequately described LY2780301 and its metabolite concentration versus time courses respectively with the estimation of the fraction of absorbed dose (fm) of LY2780301 metabolised in that metabolite. The interindividual variabilities (ISV) could be well estimated for all structural parameters (clearance: CL, volume of distribution: V, L and the absorption constant: Ka). The population PK parameters obtained for the structural model were: Ka = 0.536 h−1, CL/F = 3.57 L/h, V/F = 85.2 L, CL/(F*fm) = 13.2 L/h, V2/(F*fm) = 13.2 L, fm = 0.747 for LY2780301 and its metabolite respectively. PXL increases LY2780301 CL from 3.57 to 4.4 L/h (p = 0.016). Conclusions: We have demonstrated a PK DDI between LY2780301 and PXL. PXL increases LY2780301 CL and decreases LY2780301 AUC. PXL PK modeling is ongoing in order to verify the effect of LY2780301 on PXL PK. Citation Format: Keyvan Rezai, Samuel Huguet, Olivier Madar, Jean-Marc Extra, Magali Provansal, Carole Tarpin, Nicolas Isambert, Jihane Pakradouni, Anthony Goncalves, François Lokiec. Pharmacokinetic drug-drug interaction: a phase Ib dose escalation study of LY2780301 in combination with weekly paclitaxel. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2049.

Abstract 2036: A phase Ib pharmacokinetic drug-drug interaction evaluation of oral buparlisib in combination with lapatinib in HER2+/PI3K-activated, trastuzumab-resistant locally advanced, recurrent and metastatic breast cancer (MBC)

Abstract Background: A novel combination of oral lapatinib (LPT), a selective dual ErbB1/ErbB2 targeted drug, + oral buparlisib (B) a pan-class I PI3K inhibitor, could provide a synergestic antitumor activity in trastuzumab resistant disease. LPT has been shown to be a potent CYP3A4 inhibitor which is also mainly involved in BKM120 metabolism. In this study we investigated the potential pharmacokinetic (PK) drug-drug interactions (DDI) related to the association of B and LPT. Methods: Trastuzumab-resistant HER2 + metastatic breast cancer (MBC) patients were treated with a continuous once daily dosing schedule of LPT + B. Dose levels [DL, LPT (mg)/B (mg)] ranged from 750/40 to 1,250/80. For PK analysis, 2 time point samples were collected on D1 and D8 and 10 time point samples were collected on D15 of cycle 1 for LPT and B assays. Plasma concentrations of B and LPT, were measured using UPLC coupled with tandem mass spectrometry validated methods. Population PK was modeled using a non linear mixed effect model program (Monolix version 4.3s) by computing the maximum likelihood estimator of the parameters without any approximation of the model (no linearization). Results: 343 and 322 plasma concentrations were available for PK analysis of LPT and B respectively. A two-compartment open model adequately described B concentration versus time courses. The inter-individual variabilities (ISV) could be well estimated for all stuctural parameters (clearance: CL, volume of distribution: V, inter-compartmental clearance: Q) except for absorption constant: Ka. The population PK parameters obtained for the structural model were: Ka = 0.985 h−1, CL/F = 10.5L/h, V1/F = 54.8 L, Q/F = 46.3 L/h, V2/F = 582 L. Mean AUC0-24h(CV%) values for B were 10130 (34%), 15450 (29%), and 20560 (38%) ng*hr/mL for 40 mg, 60 mg and 80 mg dose level respectively. A one-compartment model adequately fitted the LPT plasma concentration-time data. The population PK parameters were CL/F = 25.7 L/h, V/F = 291 L and the absorption constant, Ka = 0.214 h−1. B has no significant effect on the PK of LPT and vice versa. Conclusions: B AUC increased proportionally with increasing dose. LPT PK parameters are consistent with those already published. There is no significant evidence for drug-drug PK interaction between LPT and B. Intra-occasion variabilities will be discussed. Citation Format: François Lokiec, Anthony Goncalves, Fanny Bret, Jihane Pakradouni, Magali Provansal, Renaud Sabatier, Jean-Marc Extra, Carole Tarpin, Nicolas Isambert, Mario Campone, Keyvan Rezai. A phase Ib pharmacokinetic drug-drug interaction evaluation of oral buparlisib in combination with lapatinib in HER2+/PI3K-activated, trastuzumab-resistant locally advanced, recurrent and metastatic breast cancer (MBC). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2036.

Using Nonexperts for Annotating Pharmacokinetic Drug-Drug Interaction Mentions in Product Labeling: A Feasibility Study.

BackgroundBecause vital details of potential pharmacokinetic drug-drug interactions are often described in free-text structured product labels, manual curation is a necessary but expensive step in the development of electronic drug-drug interaction information resources. The use of nonexperts to annotate potential drug-drug interaction (PDDI) mentions in drug product label annotation may be a means of lessening the burden of manual curation.ObjectiveOur goal was to explore the practicality of using nonexpert participants to annotate drug-drug interaction descriptions from structured product labels. By presenting annotation tasks to both pharmacy experts and relatively naïve participants, we hoped to demonstrate the feasibility of using nonexpert annotators for drug-drug information annotation. We were also interested in exploring whether and to what extent natural language processing (NLP) preannotation helped improve task completion time, accuracy, and subjective satisfaction.MethodsTwo experts and 4 nonexperts were asked to annotate 208 structured product label sections under 4 conditions completed sequentially: (1) no NLP assistance, (2) preannotation of drug mentions, (3) preannotation of drug mentions and PDDIs, and (4) a repeat of the no-annotation condition. Results were evaluated within the 2 groups and relative to an existing gold standard. Participants were asked to provide reports on the time required to complete tasks and their perceptions of task difficulty.ResultsOne of the experts and 3 of the nonexperts completed all tasks. Annotation results from the nonexpert group were relatively strong in every scenario and better than the performance of the NLP pipeline. The expert and 2 of the nonexperts were able to complete most tasks in less than 3 hours. Usability perceptions were generally positive (3.67 for expert, mean of 3.33 for nonexperts).ConclusionsThe results suggest that nonexpert annotation might be a feasible option for comprehensive labeling of annotated PDDIs across a broader range of drug product labels. Preannotation of drug mentions may ease the annotation task. However, preannotation of PDDIs, as operationalized in this study, presented the participants with difficulties. Future work should test if these issues can be addressed by the use of better performing NLP and a different approach to presenting the PDDI preannotations to users during the annotation workflow.

Imidazoacridinone antitumor agent C-1311 as a selective mechanism-based inactivator of human cytochrome P450 1A2 and 3A4 isoenzymes.

5-Diethylaminoethylamino-8-hydroxyimidazoacridinone (C-1311), a promising antitumor agent that is also active against autoimmune diseases, was determined to be a selective inhibitor of the cytochrome P450 (CYP) 1A2 and 3A4 isoenzymes. Therefore, C-1311 might modulate the effectiveness of other drugs used in multidrug therapy. The present work aimed to identify the mechanism of the observed C-1311-mediated inactivation of CYP1A2 and CYP3A4. The inactivation experiments were performed in vitro using the human recombinant CYP1A2 and CYP3A4 (Bactosomes). CYP isoenzyme activities were determined using the CYP-specific reactions, 7-ethoxycoumarin O-deethylation (CYP1A2) and testosterone 6β-hydroxylation (CYP3A4). The concentrations of CYP-specific substrates and their metabolites formed by CYP isoenzymes were measured by RP-HPLC with UV-Vis detection. The inhibition of CYPs by C-1311 was time-, concentration- and NADPH-dependent, which suggested a mechanism-based mode of action. Using a 10-fold dilution method and potassium ferricyanide we demonstrated the irreversible nature of the inhibition. In addition, the inhibition was attenuated by the presence of alternate substrates (alternative active site ligands) but not by a nucleophilic trapping agent (glutathione) or a reactive oxygen scavenger (catalase), which further supported a mechanism-based action. Substrate depletion partition ratios of 299 and 985 were calculated for the inactivation of CYP1A2 and CYP3A4, respectively. Our results indicated that C-1311 is a potent mechanism-based inactivator of CYP1A2 and CYP3A4. This finding provided new insights into the mechanism of C-1311 antitumor action, particularly in relation to potential pharmacokinetic drug-drug interactions between C-1311 and/or its derivatives and the substrates of CYP isoforms.

Evaluation of drug–drug interaction between henagliflozin, a novel sodium-glucose co-transporter 2 inhibitor, and metformin in healthy Chinese males

1. Henagliflozin is a novel sodium-glucose transporter 2 inhibitor and presents a complementary therapy to metformin for patients with T2DM due to its insulin-independent mechanism of action. This study evaluated the potential pharmacokinetic drug-drug interaction between henagliflozin and metformin in healthy Chinese male subjects.2. In open-label, single-center, single-arm, two-period, three-treatment self-control study, 12 subjects received 25 mg henagliflozin, 1000 mg metformin or the combination. Lack of PK interaction was defined as the ratio of geometric means and 90% confidence interval (CI) for combination: monotherapy being within the range of 0.80-1.25.3. Co-administration of henagliflozin with metformin had no effect on henagliflozin area under the plasma concentration-time curve (AUC0–24) (GRM: 1.08; CI: 1.05, 1.10) and peak plasma concentration (Cmax) (GRM: 0.99; CI: 0.92, 1.07). Reciprocally, co-administration of metformin with henagliflozin had no clinically significant on metformin AUC0–24 (GRM: 1.09, CI: 1.02, 1.16) although there was an 11% increase in metformin Cmax (GRM 1.12; CI 1.02, 1.23). All monotherapies and combination therapy were well tolerated.4. Henagliflozin can be co-administered with metformin without dose adjustment of either drug.

Prevalence and type of potential pharmacokinetic drug-drug interactions in old aged psychiatric patients

Purpose: The number of prescribed drugs increases with age, and resulting polypharmacy bears the risk of drug-drug interactions (DDI). We assessed the prevalence and type of cytochrome P450 (CYP) associated pharmacokinetic DDI that were considered as clinically relevant in elderly psychiatric patients under conditions of every day pharmacotherapy. Methods: For retrospective analysis a large therapeutic drug monitoring (TDM) data base was used. Patients included were elderly in- and outpatients, aged ≥ 65 years with a psychiatric disorder for whom serum level measurements of a psychotropic drug had been requested. Medication data were examined for co-prescription of clinically relevant CYP inhibitors or inducers and drugs that are substrates of these enzymes (victim drugs). Results: Data from 1243 patients (65.3% female) with a mean (± standard deviation) age of 73 ± 6 years were available for analysis. Mean number of prescribed drugs was 5.3 ± 3.4 per patient. Moderate (n=189, 73.8%) or strong (n=67, 26.2%) CYP inhibitors or inducers were prescribed in 18.9% of all patients. Most frequently prescribed CYP inhibitors were duloxetine (CYP2D6 inhibitor, n=73, 31.7%), melperone (CYP2D6 inhibitor, n=63, 27.4%) and omeprazole (CYP2C19 inhibitor, n=20, 8.7%). Carbamazepine was the most commonly prescribed CYP inducer (primarily CYP3A4 inducer, n=25, 96.2%). Taken inhibitory, inducing and substrate properties of combined drugs together, CYP-mediated DDI considered as clinically relevant could be detected in 133 (10.7%) of included patients. Conclusions: CYP-mediated DDI are common among elderly psychiatric patients. To avoid potentially supra- or sub-therapeutic concentrations of victim drugs, physicians should be more aware of these preventable interactions and adjust the dose.

Pharmacokinetic interaction study of ticagrelor and cyclosporine in healthy volunteers.

Patients with acute coronary syndrome and certain co-morbidities may receive ticagrelor, a reversibly binding P2Y(12) receptor antagonist, and cyclosporine, a commonly used immunosuppressant drug. This study assessed the potential pharmacokinetic drug-drug interaction between ticagrelor and cyclosporine. In this single-centre, open-label, three-treatment, three-period crossover study (NCT01504906), healthy volunteers (n = 26) randomly received each of three treatments: cyclosporine (600 mg single oral dose) plus ticagrelor (180 mg single oral dose); cyclosporine alone; ticagrelor alone. Treatments were separated by a washout period of ≥14 days. Plasma concentrations of ticagrelor and its active metabolite (AR-C124910XX) and blood concentrations of cyclosporine were analyzed, and pharmacokinetic parameters were calculated. Safety and tolerability were assessed. Compared with ticagrelor alone, the geometric least squares mean (LSM) ratio (90 % confidence interval [CI]) for the ticagrelor area under the plasma concentration-time curve from time zero to infinity (AUC(∞)) was 2.83 (2.63-3.06), and the maximum plasma concentration (C(max)) was 2.30 (2.06-2.58), in the presence of cyclosporine. Co-administration of cyclosporine with ticagrelor significantly increased AR-C124910XX AUC(∞) (1.33 [1.23-1.42]) and decreased C(max) (0.85 [0.76-0.94]). Ticagrelor had no effect on cyclosporine pharmacokinetic parameters, as the 90 % CIs of the LSM ratios were all within the 0.80-1.25 no-effect range. Co-administration of ticagrelor and cyclosporine was generally well tolerated. Co-administration of cyclosporine with ticagrelor increased exposure to ticagrelor and its active metabolite and had no effect on cyclosporine pharmacokinetic parameters. The magnitude of cyclosporine's effect on ticagrelor pharmacokinetics does not warrant dose adjustment of ticagrelor.