Dosing Recommendations Research Articles

Effects of different doses of intranasal dexmedetomidine on related complications and parents’ satisfaction in anesthetized children: a systematic review

BackgroundAgitation/delirium is commonly seen in children after anesthesia, and a proper dose of dexmedetomidine can prevent this complication. This study aimed to investigate the effects of different doses of Dexmedetomidine (DEX) on agitation/delirium and other complications in anesthetized children, providing clinical evidence for dose recommendations of DEX.MethodsThis study was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A systematic search was conducted in the Cochrane Library, PubMed, Web of Science, and EMBASE. Two independent researchers performed literature screening, data extraction, and assessed the methodological quality. Data analysis was conducted using R and STATA 16.0.ResultsIn the final analysis, 20 randomized controlled trials (RCTs) involving 2521 children were included. The results showed that in comparison to normal saline, 1 µg/kg, 1.5 µg/kg, and 2 µg/kg intranasal DEX significantly reduced the incidence of post-anesthetic emergence agitation in children with the most effective dose being 2 µg/kg (SUCRA = 0.91). Compared with normal saline, 1 µg/kg, 1.5 µg/kg, and 2 µg/kg intranasal DEX reduced patient’s need for postoperative analgesia, with the most effective dose being 1.5 µg/kg (SUCRA = 0.78). However, 1 µg/kg DEX performed the best in reducing Pediatric Anaesthesia Emergence Delirium (PAED) Scale score (SUCRA = 0.88).ConclusionCompared with normal saline, intranasal administration of 2 µg/kg DEX and 1.5 µg/kg DEX are the optimal doses to reduce the incidence of agitation and the need for postoperative pain relief in children under general anesthesia. Given effectiveness and safety, intranasal use of 1 µg/kg DEX appears to be the most effective dosage for anesthetized children.

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.

#2898 Exposure response model describing hematologic changes with chronic treatment of CKD anemia with vadadustat

Abstract Background and Aims Vadadustat (VADA) is an oral hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor, a class of drugs that stabilize HIF and stimulate endogenous erythropoietin production, increasing iron mobilization and red blood cell production. VADA is approved in 36 countries globally and is indicated in the European Union for the treatment of symptomatic anaemia associated with chronic kidney disease (CKD) in adults on chronic maintenance dialysis and is an alternative to treatment with erythropoiesis-stimulating agents (ESAs). The aim of this work was to develop a predictive, semi-mechanistic model to understand the effects of VADA and erythropoiesis-stimulating agents (ESAs) on hemoglobin response and to evaluate the impact of intrinsic and extrinsic patient characteristics on that response for non-dialysis dependent (NDD) and dialysis-dependent (DD) patient populations. Method A predictive semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model for VADA and ESA treatment was developed using nonlinear mixed effects methods. The model describes changes in reticulocyte count (RETICs), mature erythrocytes (RBCs) and hemoglobin (Hb) as a function of drug exposure and subject-specific characteristics. The dataset was based on data from 7 Phase 1 to Phase 3 studies (Table 1; N = 894 for VADA; N = 560 for ESA modeling) in healthy volunteers and subjects with NDD- or DD-CKD who were either ESA-naïve or ESA experienced but not receiving treatment at screening. Prior population PK modeling of VADA provided estimated drug exposures for VADA-treated subjects, while dose normalized to standard units (IU/kg/wk) was used as the exposure metric for subjects on ESA. Each of these exposure metrics could vary with time, as the dose was adjusted according to observed Hb response. This work evaluated alternative model structures, as well as covariate effects affecting Hb individual response. Results A predictive semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model for VADA and ESA treatment was developed using nonlinear mixed effects methods. The model describes changes in reticulocyte count (RETICs), mature erythrocytes (RBCs) and hemoglobin (Hb) as a function of drug exposure and subject-specific characteristics. The dataset was based on data from 7 Phase 1 to Phase 3 studies (Table 1; N = 894 for VADA; N = 560 for ESA modeling) in healthy volunteers and subjects with NDD- or DD-CKD who were either ESA-naïve or ESA experienced but not receiving treatment at screening. Prior population PK modeling of VADA provided estimated drug exposures for VADA-treated subjects, while dose normalized to standard units (IU/kg/wk) was used as the exposure metric for subjects on ESA. Each of these exposure metrics could vary with time, as the dose was adjusted according to observed Hb response. This work evaluated alternative model structures, as well as covariate effects affecting Hb individual response. A similar model structure was found to describe early changes in RETICs and longer-term changes in Hb for both VADA and ESAs. In each case, the magnitude of response increases with increased drug exposure up to a maximum value (Emax), and the Emax values were similar between VADA and ESAs. Subject intrinsic predictors of response included eGFR, subject age, BMI, and serum albumin, while extrinsic factors affecting response included geographic region, limits on acceptable Hb values (which also differ by geographic region) and the presence of previous ESA treatment. Interestingly, Hb responses were also correlated with changes in serum hepcidin, a key regulator of iron homeostasis, following both VADA and ESA treatment. Differences between the response to VADA and ESA were also described, including differences in temporal changes in RETICs and Hb. Conclusion This model showed an exposure-response relationship between VADA or ESA treatment and changes in RETICs and Hb for ESA naïve or ESA-experienced CKD subjects. The model will be used to inform dosage recommendations for VADA based on patient characteristics.

#2147 Enoxaparin dosing in advanced chronic kidney disease: importance of monitoring with anti-Xa levels

Abstract Background and Aims Enoxaparin is a low-molecular-weight heparin (LMWH) that is commonly used in the prevention of deep venous thrombosis (DVT) and the treatment of acute thomboembolic diseases. Current literature indicates that in advanced chronic kidney disease (CKD), there is a reduced clearance and increased half-life of LMWH and therefore, a dose adjustment is recommended. The prescription label recommends a dose adjustment of enoxaparin to 0.5 mg/kg/day for prophylaxis of DVT and 1 mg/kg/day for therapeutic anticoagulation when eGFR <30 ml/min. The aim of this study was to examine the accuracy of this dosing strategy to achieve the desired target of anticoagulation in advanced CKD. Method We conducted a prospective study in patients admitted from May 2019 to April 2023 in the Nephrology ward at our centre, who started anticoagulant treatment with enoxaparin during their in-hospital stay for prophylactic or therapeutic indications. We excluded patients with eGFR >30 ml/min at the onset of anticoagulation with enoxaparin. The dosing strategy was 0.5 mg/kg/day for prophylaxis of DVT and 1 mg/kg/day for therapeutic anticoagulation in all patients. Blood samples were drawn 4 hours after the third dose of enoxaparin to monitor anti-Xa levels in all cases. Results The study included 153 patients; 70 patients with stage 4-5 CKD and 83 patients on renal replacement therapy. 132 patients (86.3%) received enoxaparin for a therapeutic indication, while 21 patients (13.7%) received it as prophylaxis of DVT. In patients receiving enoxaparin for a therapeutic indication, 73 patients (55.3%) reached the therapeutic target anti-Xa levels (0.6-1), while 32.6% of patients had peak anti-Xa levels below the therapeutic target (<0.6) and 12.1% were over-anticoagulated (>1). There was an inverse relationship between the proportion of patients who were adequately anticoagulated and CKD stage; 66.7%, 58.6% and 48.6% of patients reached the target peak anti-Xa levels in CKD stage 4, 5 and 5D respectively. There was no significant association between anti-Xa levels and obesity or liver disease. In patients receiving enoxaparin for prophylaxis of DVT, 42.9% reached the target anti-Xa levels for prophylaxis (0.3-0.6), while 38.1% had anti-Xa levels below this range and 19% were over-anticoagulated. Conclusion The enoxaparin dosing recommendations indicated by its label entails a high proportion of patients with advanced CKD who do not achieve the target therapeutic levels of antiXa, especially in patients on renal replacement therapy. To ensure adequate anticoagulation in these patients, we recommend using individualized dosing adjustments based on monitoring of anti-Xa levels for the prevention of thromboembolic events and reducing the risk of hemorrhagic events.

Intervention Bundle for Optimization of Procedural Sedation for Newborns Undergoing Magnetic Resonance Imaging: A Single-Center Quality Improvement Project in Qatar

Introduction: Magnetic resonance imaging (MRI) is a common procedure in tertiary care neonatal intensive care units (NICUs). MRIs aid in detailing structural anatomy and are increasingly utilized for prognostication. Keeping babies calm and motion-free in the MRI suite is challenging, and various approaches have been adopted to obtain the best image quality. We share our experience of intervention bundle for procedural sedation with the novel use of buccal midazolam in our NICU for babies undergoing MRI. Methods: This single-center quality improvement project comprised two epochs. Epoch 1 from April 2018 to December 2020 provided baseline data regarding sedation use and helped identify causes for suboptimal images and the adverse event rate. Following the implementation of an interventional bundle comprising specific midazolam dose recommendations tailored to background risk factors and streamlining the procedural sedation process, similar comparative data were collected in epoch 2 (May 2021 to December 2022) after a washout period. Results: Of 424 patients, 238 and 108 had MRI done under either procedural sedation protocol or feed and wrap technique in epoch 1 and 2, respectively. After excluding babies whose MRIs were performed under sedative infusions, 30 (13%) babies had adverse events in epoch 1, while only 8 (7%) events occurred in epoch 2. There was also a 37% improvement in the documentation of procedural sedation between the two epochs. Conclusion: Procedural sedation with buccal midazolam under neonatologist supervision is safe, efficient, and effective in babies undergoing MRI in this single-center study. More extensive studies may be warranted to assess the suitability of this sedation modality for broader use.

Comparison of shielding effects of over-glasses-type and regular eyewear in terms of occupational eye dose reduction

Given the new recommendations for occupational eye lens doses, various lead glasses have been used to reduce irradiation of interventional radiologists. However, the protection afforded by lead glasses over prescription glasses (thus over-glasses-type eyewear) has not been considered in detail. We used a phantom to compare the protective effects of such eyewear and regular eyewear of 0.07 mm lead-equivalent thickness. The shielding rates behind the eyewear and on the surface of the left eye of an anthropomorphic phantom were calculated. The left eye of the phantom was irradiated at various angles and the shielding effects were evaluated. We measured the radiation dose to the left side of the phantom using RPLDs attached to the left eye and to the surface/back of the left eyewear. Over-glasses-type eyewear afforded good protection against x-rays from the left and below; the average shielding rates on the surface of the left eye ranged from 0.70–0.72. In clinical settings, scattered radiation is incident on physicians’ eyes from the left and below, and through any gap in lead glasses. Over-glasses-type eyewear afforded better protection than regular eyewear of the same lead-equivalent thickness at the irradiation angles of concern in clinical settings. Although clinical evaluation is needed, we suggest over-glasses-type Pb eyewear even for physicians who do not wear prescription glasses.

Assessment of Cefuroxime and Cefuroxime Clavulanic Acid Prescription Practices for Infection Management in Routine Indian Healthcare Settings: Expert Insights

Background: Cefuroxime axetil has shown effectiveness as part of intravenous/oral sequential therapy for community-acquired pneumonia (CAP) treatment, although some countries currently lack dosage recommendations for this regimen. In addition, the perspectives of clinicians were not studied. So, this study evaluated the prescription practice of cefuroxime, and cefuroxime+ clavulanic acid in the management of infections in routine Indian settings. Methods: The cross-sectional survey, titled ‘Cefuroxime & Cefuroxime+Clavulanic acid in Management of Infections: Expert Perspective (CARE) Study’, utilized a 20-item, multiple-response questionnaire to gather expert opinion from specialists regarding the clinical use of cefuroxime and cefuroxime + clavulanic acid in managing infections. The survey encompassed questions about current prescription practices, clinical observations, preferences, and experiences related to the use of these antibiotics in routine settings. Results: Among the 164 clinicians surveyed, 78% of the respondents indicated that cefuroxime was highly effective in managing lower respiratory tract infections. Additionally, 91% of the experts stated that the combination of cefuroxime and clavulanic acid was very effective in managing infections. The majority of clinicians recommended cefuroxime + clavulanic acid as the initial therapy for complicated urinary tract infections (88%), as well as first-line therapy for uncomplicated skin and soft tissue infections (45%) and community-acquired pneumonia (58%). According to 40% of the clinicians, cefuroxime + clavulanic acid was recommended as the initial therapy for 21-30% of patients suspected of methicillin-resistant Staphylococcus aureus infection. Most respondents (88%) preferred cefuroxime + clavulanic acid as the antibiotic for managing Pseudomonas aeruginosa infection. Conclusion: The survey has emphasized the critical role of cefuroxime and cefuroxime + clavulanic acid as antibiotics in managing diverse infections. Clinicians' recognition of their efficacy and preference for combination therapy has underscored the importance of antibiotic stewardship in optimizing patient care.

Optimal management of radiation pneumonitis: Findings of an international Delphi consensus study

PurposeRadiation pneumonitis (RP) is a dose-limiting toxicity for patients undergoing radiotherapy (RT) for lung cancer, however, the optimal practice for diagnosis, management, and follow-up for RP remains unclear. We thus sought to establish expert consensus recommendations through a Delphi Consensus study. MethodsIn Round 1, open questions were distributed to 31 expert clinicians treating thoracic malignancies. In Round 2, participants rated agreement/disagreement with statements derived from Round 1 answers using a 5-point Likert scale. Consensus was defined as ≥ 75 % agreement. Statements that did not achieve consensus were modified and re-tested in Round 3. ResultsResponse rate was 74 % in Round 1 (n = 23/31; 17 oncologists, 6 pulmonologists); 82 % in Round 2 (n = 19/23; 15 oncologists, 4 pulmonologists); and 100 % in Round 3 (n = 19/19). Thirty-nine of 65 Round 2 statements achieved consensus; a further 10 of 26 statements achieved consensus in Round 3. In Round 2, there was agreement that risk stratification/mitigation includes patient factors; optimal treatment planning; the basis for diagnosis of RP; and that oncologists and pulmonologists should be involved in treatment. For uncomplicated radiation pneumonitis, an equivalent to 60 mg oral prednisone per day, with consideration of gastroprotection, is a typical initial regimen. However, in this study, no consensus was achieved for dosing recommendation. Initial steroid dose should be administered for a duration of 2 weeks, followed by a gradual, weekly taper (equivalent to 10 mg prednisone decrease per week). For severe pneumonitis, IV methylprednisolone is recommended for 3 days prior to initiating oral corticosteroids. Final consensus statements included that the treatment of RP should be multidisciplinary, the uncertainty of whether pneumonitis is drug versus radiation-induced, and the importance risk stratification, especially in the scenario of interstitial lung disease. ConclusionsThis Delphi study achieved consensus recommendations and provides practical guidance on diagnosis and management of RP.

Pooled Population Pharmacokinetic Analysis and Dose Recommendations for Ciprofloxacin in Intensive Care Unit Patients with Obesity.

Recent studies have explored the influence of obesity and critical illness on ciprofloxacin pharmacokinetics. However, variation across the subpopulation of individuals with obesity admitted to the intensive care unit (ICU) with varying renal function remains unexamined. This study aims to characterize ciprofloxacin pharmacokinetics in ICU patients with obesity and provide dose recommendations for this special population. Individual patient data of 34 ICU patients with obesity (BMI >30 kg/m2) from four studies evaluating ciprofloxacin pharmacokinetics in ICU patients were pooled and combined with data from a study involving 10 individuals with obesity undergoing bariatric surgery. All samples were collected after intravenous administration. Non-linear mixed effects modeling and simulation were used to develop a population pharmacokinetic model and describe ciprofloxacin exposure in plasma. Model-based dose evaluations were performed using a pharmacokinetic/pharmacodynamic target of AUC/MIC >125. The data from patients with BMI ranging from 30.2 to 58.1 were best described by a two-compartment model with first-order elimination and a proportional error model. The inclusion of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) as a covariate on clearance reduced inter-individual variability from 57.3% to 38.5% (P <.001). Neither body weight nor ICU admission significantly influenced clearance or volume of distribution. Renal function is a viable predictor for ciprofloxacin clearance in ICU patients with obesity, while critical illness and body weight do not significantly alter clearance. As such, body weight and critical illness do not need to be accounted for when dosing ciprofloxacin in ICU patients with obesity. Individuals with CKD-EPI >60 mL/min/1.73 m2 may require higher dosages for the treatment of pathogens with minimal inhibitory concentration ≥0.25 mg/L.

Hematologic Toxicity and Bone Marrow-Sparing Strategies in Chemoradiation for Locally Advanced Cervical Cancer: A Systematic Review.

The standard treatment for locally advanced cervical cancer typically includes concomitant chemoradiation, a regimen known to induce severe hematologic toxicity (HT). Particularly, pelvic bone marrow dose exposure has been identified as a contributing factor to this hematologic toxicity. Chemotherapy further increases bone marrow suppression, often necessitating treatment interruptions or dose reductions. A systematic search for original articles published between 1 January 2006 and 7 January 2024 that reported on chemoradiotherapy for locally advanced cervical cancer and hematologic toxicities was conducted. Twenty-four articles comprising 1539 patients were included in the final analysis. HT of grade 2 and higher was observed across all studies and frequently exceeded 50%. When correlating active pelvic bone marrow and HT, significant correlations were found for volumes between 10 and 45 Gy and HT of grade 3 and higher. Several dose recommendations for pelvic bone and pelvic bone marrow sparing to reduce HT were established, including V10 < 90-95%, V20 < 65-86.6% and V40 < 22.8-40%. Applying dose constraints to the pelvic bone/bone marrow is a promising approach for reducing HT, and thus reliable implementation of therapy. However, prospective randomized controlled trials are needed to define precise dose constraints and optimize clinical strategies.

Meropenem Disposition in Neonatal and Pediatric Extracorporeal Membrane Oxygenation and Continuous Renal Replacement Therapy.

This study aimed to characterize the impact of extracorporeal membrane oxygenation (ECMO) on the pharmacokinetics (PK) of meropenem in neonates and children and to provide recommendations for meropenem dosing in this specific population of patients. Therapeutic drug monitoring (152 meropenem plasma concentrations) data from 45 patients (38 received ECMO) with a body weight (BW) of 7.88 (3.62-11.97) kg (median (interquartile range)) and postnatal age of 3 (0-465) days were collected. The population PK analysis was performed using NONMEM V7.3.0. Monte Carlo simulations were performed to assess the probability of target achievement (PTA) for 40% of time the free drug remained above the minimum inhibitory concentration (fT > MIC) and 100% fT > MIC. BW was found to be a significant covariate for the volume of distribution (Vd) and clearance (CL). Additionally, continuous renal replacement therapy (CRRT) was associated with a two-fold increase in Vd. In the final model, the CL and Vd for a typical patient with a median BW of 7.88 kg that was off CRRT were 1.09 L/h (RSE = 8%) and 3.98 L (14%), respectively. ECMO did not affect meropenem PK, while superimposed CRRT significantly increased Vd. We concluded that current dosing regimens provide acceptably high PTA for MIC ≤ 4 mg/L for 40% fT > MIC, but individual dose adjustments are needed for 100% fT > MIC.

Approval of Mycophenolate Mofetil for Prophylaxis of Organ Rejection in Pediatric Recipients of Heart or Liver Transplants: A Regulatory Perspective.

On June 6, 2022, the FDA expanded the indications for mycophenolate mofetil (MMF) to include the prophylaxis of organ rejection in combination with other immunosuppressants in pediatric recipients of allogeneic heart or liver transplants aged 3 months and older. The approved oral dosing regimen for these patients was a starting dose of 600 mg/m2 with titration up to a maximum of 900 mg/m2 twice daily. Data to support efficacy in pediatric patients were derived from established pharmacokinetic (PK) relationships across approved populations, a PK study in pediatric liver transplant recipients, and information from the Scientific Registry of Transplant Recipients database. Information supporting safety was based on comparing mycophenolic acid (MPA) exposure with that in pediatric kidney transplant recipients, the published literature, and post-marketing safety reports. Efficacy in pediatric patients was established based on extrapolation of efficacy from studies in adult liver, adult heart, and pediatric kidney transplant populations, and similarity in MPA exposure between pediatric and adult patients. Review of the data supported an oral dosing regimen for pediatric heart transplant and liver transplant recipients consisting of a starting dose of 600 mg/m2 up to a maximum of 900 mg/m2 b.i.d. A dosage range for MMF is recommended recognizing that the MMF dose may be modified in clinical practice for myriad factors. The dosage recommendations in the labeling for pediatric liver and pediatric heart transplant patients are intended to permit individualized dosing based on clinical assessment of these factors.

Re-discover the value of protein binding assessments in hepatic and renal impairment studies and its contributions in drug labels and dose decisions.

One of the key pharmacokinetic properties of most small molecule drugs is their ability to bind to serum proteins. Unbound or free drug is responsible for pharmacological activity while the balance between free and bound drug can impact drug distribution, elimination, and other safety parameters. In the hepatic impairment (HI) and renal impairment (RI) clinical studies, unbound drug concentration is often assessed; however, the relevance and impact of the protein binding (PB) results is largely limited. We analyzed published clinical safety and pharmacokinetic studies in subjects with HI or RI with PB assessment up to October 2022 and summarized the contribution of PB results on their label dose recommendations. Among drugs with HI publication, 32% (17/53) associated product labels include PB results in HI section. Of these, the majority (9/17, 53%) recommend dose adjustments consistent with observed PB change. Among drugs with RI publication, 27% (12/44) of associated product labels include PB results in RI section with the majority (7/12, 58%) recommending no dose adjustment, consistent with the reported absence of PB change. PB results were found to be consistent with a tailored dose recommendation in 53% and 58% of the approved labels for HI and RI section, respectively. We further discussed the interpretation challenges of PB results, explored treatment decision factors including total drug concentration, exposure-response relationships, and safety considerations in these case examples. Collectively, comprehending the alterations in free drug levels in HI and RI informs treatment decision through a risk-based approach.

Dose Optimization Informed by PBPK Modeling: State-of-the Art and Future.

Model-informed drug development (MIDD) is a powerful quantitative approach that plays an integral role in drug development and regulatory review. While applied throughout the life cycle of the development of new drugs, a key application of MIDD is to inform clinical trial design including dose selection and optimization. To date, physiologically-based pharmacokinetic (PBPK) modeling, an established component of the MIDD toolkit, has mainly been used for assessment of drug-drug interactions (DDIs) and consequential dose adjustments in regulatory submissions. As a result of recent scientific advances and growing confidence in the utility of the approach, PBPK models are being increasingly applied to provide dose recommendations for subjects with differing ages, genetics, and disease states. In this review, we present our perspective on the current landscape of regulatory acceptance of PBPK applications supported by relevant case studies. We also discuss the recent progress and future challenges associated with expanding the utility of PBPK models into emerging areas for regulatory decision making, especially dose optimization in highly vulnerable and understudied populations and facilitating diversity in clinical trials.

"Getting the Dose Right"-Revisiting the Topic With Focus on Biologic Agents.

Nearly two decades after the Peck and Cross article '"Getting the dose right: facts, a blueprint, and encouragements" was published, a review of dose recommendations for biologics shows that the success in getting the dose right appears to have improved given the relatively low incidence of drug withdrawals and dosing/label changes. However, the clinical experience with monoclonal antibodies (MAbs) following approval has been less than perfect. In inflammatory diseases, the disease burden changes with time and high treatment failure rates have been reported. In addition, the use of concomitant steroids and immunosuppressant drugs with MAbs is common. These concomitant agents have their own safety issues and many immunosuppressant agents are not well-tolerated although they have been shown to reduce the incidence of anti-drug antibodies (ADA). This same complexity is seen in MAbs used in oncology as well, although with these agents the doses appear to be higher than needed, which results in high treatment costs and incidence of adverse events. Given the complexity of MAb pharmacokinetics, which makes providing a detailed description of dose options difficult, product labeling should include the options for alternative dose strategies and potentially include the use of therapeutic drug monitoring with dose individualization which have been shown to improve clinical response and reduce the incidence of ADA. So, while the recommended dosing for biologics seems improved over the issues noted 17 years ago, we still have some work to do.

Potential for Optimization of Growth Hormone Treatment in Children with Growth Hormone Deficiency, Small for Gestational Age, and Turner Syndrome in Germany: Data from the PATRO® Children Study

Introduction: Growth hormone (GH) treatment in children with growth hormone deficiency (GHD), short children born small for gestational age (SGA), and Turner syndrome (TS) is well established. However, a variety of parameters are still under discussion to achieve optimal growth results and efficiency of GH use in real-world treatment. Methods: German GH-treatment naïve patients of the PATRO Children database were grouped according to their start of treatment into groups of 3 years from 2007 to 2018. Time trends in age, gender, GH dose, height standard deviation score (SDS), first-year growth response, and Index of Responsiveness (IoR) were investigated in children with GHD, short children born SGA, and TS starting GH treatment in the German patient population of the PATRO Children database from 2007 to 2018 to determine specific parameters for GH treatment optimization. Results: All patient groups started GH treatment at a relatively high chronological age (2007–2009: GHD 8.33 ± 3.19, SGA 7.32 ± 2.52, TS 8.65 ± 4.39) with a slight but not significant trend towards younger therapy start up to 2016–2018 (GHD 8.04 ± 3.36, SGA 6.67 ± 2.65, TS 7.85 ± 3.38). In the GHD and SGA groups, female patients were underrepresented compared to male patients (GHD 32.3%, SGA 43.6%) with no significant change over the 4 time periods. Patients with GHD started GH treatment at a low dose (0.026 mg/kg/day). In SGA and TS patients, GH therapy was started below the registered dose recommendation (30.0 μg/kg/day and 33.7 μg/kg/day, respectively). In the first year of treatment, the mean GH dose was increased moderately (GHD: 30.7, SGA: 35.7, TS: 40.8 μg/kg/day). There was no significant change of GH dosing over time from 2007 to 2018. The IoR was comparable between time-groups for all 3 diagnoses. Discussion: This study shows potential for improvement of GH treatment results in GHD, SGA, and TS patients in terms of early dose adjustment and younger age at the start of treatment. This is in accordance with important parameters used in prediction models.

CoaguChek and Coag-Sense PT2 Meter Point of Care INR Device Validation

ObjectiveTo standardize international normalized ratio (INR) measurements and improve data integrity by enabling electronic result transmission for warfarin monitoring, two point-of-care (POC) devices were evaluated against an internal plasma INR reference method. MethodsA multicenter study was pursued (January 24, 2022, through October 19, 2022) to compare concordance of two commercially available POC devices, Coag-Sense PT2 Meter (Coag-Sense) and CoaguChek XS Pro and Plus devices (CoaguChek), against an internal plasma INR method among patients treated with warfarin. Bias and linear regression analysis were assessed for these devices including dosing decision accuracy compared with plasma INR reference. ResultsTwo hundred ninety-nine patients treated with warfarin across three Mayo Clinic sites agreed to participate. Atrial fibrillation (n=191, 63.9%), venous thromboembolism (n=65; 21.7%), and heart valve prosthesis (n=46; 15.4%) were common anticoagulant indications with a 2.5 INR target for 280 (93.6%) of patients. For the CoaguChek devices, 243 (81.3%) of values fell within 0.2 INR units with plasma INR referent and 285 (95.3%) within 0.4 units (R2=0.93). For the Coag-Sense device, 102 (34.1%) of values fell within 0.2 INR units and 180 (60.2%) within 0.4 INR units of plasma INR values, (R2=0.83; P<.0001). Using the plasma INR as the gold standard, appropriate dosing recommendations would have occurred for 292 (97.7%) of the CoaguChek and 244 (81.6%) of the Coag-Sense results. ConclusionCompared with a plasma referent, INR values obtained from the CoaguChek devices exhibited less systematic bias compared with Coag-Sense measures. This translates to a greater percentage of concordant management decisions between POC and laboratory INR methods.

Hepatic Dysfunction Quantified by HepQuant DuO Outperforms Child-Pugh Classification in Predicting the Pharmacokinetics of Ampreloxetine.

HepQuant tests quantify liver function from clearance of deuterium- and 13C-labeled cholates administered either intravenously and orally (SHUNT) or orally (DuO). Hepatic impairment studies have relied on clinical or laboratory criteria like Child-Pugh classification to categorize the degree of hepatic dysfunction. We compared HepQuant tests with Child-Pugh classification in predicting the pharmacokinetics of ampreloxetine. Twenty-one subjects with hepatic impairment (8 Child-Pugh A, 7 Child-Pugh B, and 6 Child-Pugh C), and 10 age- and sex-matched controls were studied. The pharmacokinetics of ampreloxetine were measured after oral administration of a single dose of 10 mg. Disease severity index (DSI), portal-systemic shunting (SHUNT%), hepatic reserve, and hepatic filtration rates (HFRs) were measured from serum samples obtained after intravenous administration of [24-13C]-cholate and oral administration of [2,2,4,4-2H]cholate. Ampreloxetine plasma exposure (AUC0-inf) was similar to controls in Child-Pugh A, increased 1.7-fold in subjects with Child-Pugh B, and 2.5-fold in subjects with Child-Pugh C and correlated with both Child-Pugh score and HepQuant parameters. The variability observed in ampreloxetine exposure (AUC0-inf) in subjects with moderate (Child-Pugh B) and severe hepatic impairment (Child-Pugh C) was explained by HepQuant parameters. Multivariable regression models demonstrated that DSI, SHUNT%, and Hepatic Reserve from SHUNT and DuO were superior predictors of ampreloxetine exposure (AUC0-inf) compared to Child-Pugh score. HepQuant DSI, SHUNT%, and hepatic reserve were more useful predictors of drug exposure than Child-Pugh class for ampreloxetine and thus may better optimize dose recommendations in patients with liver disease. The simple-to-administer, oral-only DuO version of the HepQuant test could enhance clinical utility.

The Impact of Augmented Renal Clearance on Vancomycin Pharmacokinetics and Pharmacodynamics in Critically Ill Patients.

Augmented renal clearance (ARC), defined as a creatinine clearance (CrCl) > 130 mL/min/1.73 m2, is observed in 30-65% of critically ill patients. When following standard dosage guidelines, patients with ARC often experience subtherapeutic vancomycin levels, resulting in treatment failure due to accelerated drug elimination. This review aims to explore ARC's impact on vancomycin pharmacokinetics and pharmacodynamics (PK/PD) indices in ARC patients, seeking to identify an accurate dose adjustment method for this patient population. In September 2023, a comprehensive literature search was conducted on the MEDLINE and EMBASE databases to include all available studies providing information on the impact of ARC on vancomycin therapy in critically ill adults. Articles that studied the pediatric population and those with insufficient PK data were excluded. A total of 21 articles met the inclusion criteria. The findings revealed a positive correlation between CrCl and vancomycin clearance, indicating low serum concentrations. Therefore, upward dosing adjustments are necessary to improve treatment success. Younger age consistently emerged as a major contributor to ARC and vancomycin PK/PD alterations. This study summarizes the PK/PD alterations, current dosage recommendations and proposes preliminary recommendations on possible dosing approaches to decrease the risk of subtherapeutic exposure in this patient population.

Knowledge of and Stated Adherence to the 2020 ACR Guideline for Gout Management: Results of a Survey of US Rheumatologists.

This report evaluates rheumatologists' stated adherence to and agreement with the 2020 American College of Rheumatology (ACR) Guideline for the Management of Gout. A 57-item questionnaire was administered to a sample of US rheumatologists. Stated adherence scores were based on several guideline recommendations reported to be followed by rheumatologists in practice, whereas stated agreement scores were based on whether respondents always followed the recommendations. All 201 rheumatologists approached completed the questionnaire. The mean overall stated adherence score was 11.5 (maximum 15), whereas the mean overall stated agreement score was 7.7 (maximum 14). Less experienced rheumatologists (≤ 8 yrs; n = 49) were likely to claim adherence to more individual ACR recommendations than those with more experience (> 8 yrs; n = 152; mean stated adherence score: 12.3 vs 11.3; P ≤ 0.05). Rheumatologists who claimed to see ≤ 75 patients with gout in 6 months (n = 66) had a mean stated adherence score of 12.1 vs 11.2 for those who claimed to have seen > 75 patients (P ≤ 0.05). Approximately 78% of rheumatologists claimed to follow the guideline for initiating urate-lowering therapy (ULT), and 89% were likely to prescribe allopurinol as a first-line ULT. Claimed adherence to recommendations for dosing was lower (febuxostat: 43%; allopurinol: 39%). Rheumatologists from academic settings were more likely to prescribe an interleukin-1 inhibitor for gout flares. The self-reported practice of the surveyed US rheumatologists was generally concordant with the 2020 ACR Guideline for the Management of Gout. However, there were gaps in guideline knowledge and stated adherence among rheumatologists, mainly concerning the dosing of treatment regimens.