Optimal Dose Selection Research Articles

In silico molecular targets, docking, dynamics simulation and physiologically based pharmacokinetics modeling of oritavancin

IntroductionOritavancin is a semi-synthetic lipoglycopeptide antibiotic primarily used to treat serious infections caused by Gram-positive bacteria. The aim of this study was to elucidate possible molecular targets of oritavancin in human and microbes in relevance to its mechanism of action and model its pharmacokinetics for optimal dose selection in clinical practice.MethodsComputational methods were used in this study which include target prediction, molecular docking, molecular dynamics simulation, pharmacokinetics prediction, and physiological-based pharmacokinetics (PBPK) modeling.ResultsOritavancin was moderately soluble in water and did not permeate the blood-brain barrier. Seven molecular targets were identified in humans. Molecular docking results showed highest binding affinity of oritavancin with PI3-kinase p110-gamma subunit (−10.34 kcal/mol), followed by Acyl-CoA desaturase (−10.07 kcal/mol) and Cytochrome P450 2C19 (−8.384 kcal/mol). Oritavancin PBPK modelling in adult human showed that infusion has lower peak concentrations (Cmax) compared to bolus administration, with 1200 mg dose yielded Cmax of 16.559 mg/L, 800 mg dose yielded Cmax of 11.258 mg/L, and 200 mg over 3 days dose yielded Cmax of 7.526 mg/L. Notably, infusion gave extended half-life (t1/2) for all doses and slightly higher clearance rates compared to bolus, particularly for the 1200 mg and 800 mg doses. The results corroborated existing clinical pharmacokinetic data, and confirmed the model’s accuracy and predictive capability.ConclusionThis comprehensive computational study has provided invaluable insights into the pharmacological profile of Oritavancin, aiding its further development and optimization for clinical use.

Exposure-Response-Based Multiattribute Clinical Utility Score Framework to Facilitate Optimal Dose Selection for Oncology Drugs.

The advent of new therapeutic modalities highlighted deficiencies in the traditional maximum tolerated dose approach for oncology drug dose selection and prompted the Food and Drug Administration (FDA)'s Project Optimus initiative, which suggests that sponsors take a holistic approach, including efficacy, safety, and pharmacokinetic (PK) and pharmacodynamic data, in conjunction with integrated exposure-response (ER) analyses. However, this method comes with an inherent challenge of the collation of the multisource data. To address this issue, an ER-based clinical utility score (CUS) framework, combining benefit and risk into a single measurement, was developed. Model-predicted outcomes for each clinically relevant end point, informed by ER modeling, are converted to a CUS using a user-defined utility function. Thereafter, individual CUS is integrated into a single score with user-defined weighting for each end point. The user-defined weighting feature allows the user to incorporate expert knowledge/understanding into weighing the product's benefit versus risk profile. To validate the framework, data were leveraged from over 50 oncology programs from 2019 to 2023 on the basis of FDA new drug application/biologics license application review packages and/or related literature studies. Five representative cases were selected for in-depth evaluation. Results showed that the optimal benefit-risk ratio (highest CUS) was consistently observed at PK exposures synonymous with recommended doses. A recurring theme across cases was a greater emphasis on safety over efficacy in oncology drug dose determination. The ER-based CUS framework offers a strategic tool to navigate the complexities of dose selection in oncology programs. It serves as a pillar to the importance of integrative data analysis, aligning with the vision of Project Optimus, and demonstrates its potential in guiding dose optimization by balancing therapeutic benefits against risk.

Restoration of Radiosensitivity by Soya Isoflavone Genistein is Accomplished by Facilitating DNA Damage Response in Radioresistant Cervical Cancer in vitro

ABSTRACT Context: Enhancing radiotherapeutic efficacy in tumor cells and sparing the normal tissues are major clinical concerns for the betterment of cancer therapy. Genistein (GEN) being a radiosensitizer ameliorates the effectiveness of radiation-induced cell killing by inducing DNA damage. This molecule is accountable for minimizing radiation-related toxicity and protecting healthy cells. However, the explicit mechanism of action of such molecules needs exploration. Aims: The objective of this study is to investigate the mechanistic action of GEN in cervical cancer cell radiosensitization. Settings and Design: Cervical squamous carcinoma cell SiHa and a radioresistant subline SiHa/RR (developed and isolated from SiHa) were taken for this study. The experiments were performed by pretreating the cells with IC30 dose of GEN, followed by acute irradiation to detect the impact of GEN in imparting radiosensitivity. Subjects and Methods: Optimal dose selection of GEN was performed by MTT assay, and radiosensitizing potency was determined by pretreating the cells with IC30 dose of GEN, followed by challenging with acute incremental doses of radiation. Mechanistic parameters were checked by clonogenic assay, cell cycle analysis, DNA damage estimation, apoptosis, and wound healing-sphere-forming assay. Statistical Analysis Used: Statistical analysis was performed in GraphPad software by performing the Student’s t-test. Results: Results depicted decreased numbers of colonies, increased frequency of DNA damage and apoptotic cells, and suppressed wound healing ability along with restrained sphere-forming ability upon the intervention of cells with GEN before radiation exposure. Such observations implied that GEN pretreatment renders improved radiosensitivity in cervical cancer by increased DNA damage-mediated G2/M arrest with subsequent apoptosis. Conclusions: GEN by inducing DNA damage stimulates radiation-induced cell killing in vitro.

U-MET: Utility-Based Dose Optimization Approach for Multiple-Dose Randomized Trial Designs

The advent of dose optimization has led to a paradigm shift in oncology clinical trials to find the optimal biologic dose (OBD). Phase 1/2 trials with randomized doses can facilitate additional investigation of the identified OBD in a targeted population by incorporating safety and efficacy data. We propose to compare randomized doses by extending the Bayesian optimal interval phase 1/2 (BOIN12) approach, an OBD-finding design in which a utility is used to account for risk-benefit tradeoffs. Specifically, we used the BOIN12 standardized mean utilities in a hypothesis testing framework, in which frequentist and Bayesian inference were evaluated to compare the standardized mean utilities across doses and identify the OBD. We performed simulation studies and a hypothetical oncology study to compare the proposed BOIN12 utility-based extension (U-MET) design with an empirical design. The results demonstrated that the U-MET design has satisfactory operating characteristics for selecting the OBD. We recommend using the U-MET design as the primary dose comparison approach, or alternatively as supportive evidence, for optimal dose selection.

Leveraging pharmacokinetic parameters as covariate in Bayesian logistic regression model to optimize dose selection in early phase oncology trial

ABSTRACT Dose selection and optimization in early phase of oncology drug development serves as the foundation for the success of late phases drug development. Bivariate Bayesian logistic regression model (BLRM) is a widely utilized model-based algorithm that has been shown to improve the accuracy for identifying recommended phase 2 dose (RP2D) based on dose-limiting-toxicity (DLT) over traditional method such as 3 + 3. However, it remains a challenge to optimize dose selection that strikes a proper balance between safety and efficacy in escalation and expansion phase of phase I trials. In this paper, we first use a phase I clinical trial to demonstrate how the variability of drug exposure related to pharmacokinetic (PK) parameters among trial participants may add to the difficulties of identifying optimal dose. We use simulation to show that concurrently or retrospectively fitting BLRM model for dose/toxicity data from escalation phase with dose-independent PK parameters as covariate lead to improved accuracy of identifying dose level at which DLT rate is within a prespecified toxicity interval. Furthermore, we proposed both model- and rule-based methods to modify dose at patient level in expansion cohorts based on their PK/exposure parameters. Simulation studies show this approach leads to higher likelihood for a dose level with a manageable toxicity and desirable efficacy margin to be advanced to late phase pipeline after being screened at expansion phase of phase I trial.

A seamless phase II/III design with dose optimization for oncology drug development.

The US FDA's Project Optimus initiative that emphasizes dose optimization prior to marketing approval represents a pivotal shift in oncology drug development. It has a ripple effect for rethinking what changes may be made to conventional pivotal trial designs to incorporate a dose optimization component. Aligned with this initiative, we propose a novel seamless phase II/III design with dose optimization (SDDO framework). The proposed design starts with dose optimization in a randomized setting, leading to an interim analysis focused on optimal dose selection, trial continuation decisions, and sample size re-estimation (SSR). Based on the decision at interim analysis, patient enrollment continues for both the selected dose arm and control arm, and the significance of treatment effects will be determined at final analysis. The SDDO framework offers increased flexibility and cost-efficiency through sample size adjustment, while stringently controlling the Type I error. This proposed design also facilitates both accelerated approval (AA) and regular approval in a "one-trial" approach. Extensive simulation studies confirm that our design reliably identifies the optimal dosage and makes preferable decisions with a reduced sample size while retaining statistical power.

Exposure-response analyses for optimal therapeutic dose selection of ABBV-383 in patients with relapsed/refractory multiple myeloma (RRMM).

7541 Background: ABBV-383 is a fully human, B-cell maturation antigen (BCMA) × CD3 T-cell–engaging IgG4 bispecific with an effector-silenced Fc region, 2 high-affinity BCMA- and a low-affinity CD3-binding domains. ABBV-383 monotherapy has shown promising activity in patients (pts) with RRMM (Blood 2023;142[suppl 1]:3378). Here, exposure-response (ER) analyses of efficacy and safety endpoints supporting the optimal therapeutic ABBV-383 dose selection are reported in alignment with US FDA’s Project Optimus. Methods: Efficacy (n=218) and safety (n=220) data from the phase 1 study (NCT03933735) escalation cohorts of 0.025 - 120 mg Q3W and expansion cohorts of 20, 40, 60 mg Q3W and 60 mg Q4W including objective response rate (ORR), very good partial response or better (≥VGPR), stringent complete response (sCR)/CR, adverse events (≥G3 and serious), infections (≥G3, overall and serious), cytokine release syndrome (CRS; any-grade, G1, G2, and ≥G2) were modeled. Total(unbound + bound to soluble BCMA) and free (unbound + partially bound to soluble BCMA) Cycle 1 AUCinf, Cmax, and Ctrough and population pharmacokinetic model-derived up to the time of event Cavg and avgCtrough metrics were utilized in the ER analyses (logistic regression; R Version 4.2.2). Relevant pt-specific covariates were tested. Dexamethasone premedication (36 vs 10 mg) was included in CRS models. The ER relationships were utilized to predict the probabilities of efficacy and safety endpoints for relevant doses and thereby, support justification of the optimal therapeutic dose selection. Results: Based on overall assessment, ORR, ≥VGPR, sCR/CR and ≥G3 neutropenia strongly correlated with free Cavg; CRS endpoints (any-grade CRS and G1 only CRS) strongly correlated with Cycle 1 total Cmax (p <0.05). No other endpoints had ER relationships (p >0.05). Only MM type (IgG vs Others) was selected in ≥VGPR and sCR/CR models. ER relationships suggested high response rates of >63% ORR, >53% ≥VGPR, and ≥30% sCR/CR for 40, 60 mg Q3W and 60 mg Q4W. Predictions demonstrated that 20 mg Q3W (<39% ORR and ≥VGPR; <13% sCR/CR) and untested 40 mg Q4W (<60% ORR, <45% ≥VGPR and <23% sCR/CR) provide suboptimal efficacy. The 60 mg Q4W with 36 mg dexamethasone in Cycle1 (limited follow-up and data) was predicted to have ~30% sCR/CR and 31% ≥G3 neutropenia (≈ 40 mg Q3W) and substantially lower any-grade CRS events compared with 40 and 60 mg doses with 10 mg dexamethasone in Cycle 1. Conclusions: While ER analyses indicated promising efficacy and acceptable safety profiles for 40, 60 mg Q3W, and 60 mg Q4W, they support 60 mg Q4W as the optimal ABBV-383 therapeutic dose due to its predicted better therapeutic benefit/risk profile (high response rates, improved/equivalent ≥G3 neutropenia, and lower CRS events) and extended dosing interval. ABBV-383 at 60 mg Q4W will be investigated in the registrational phase 3 trial (NCT06158841) in RRMM.

Contemporary radiation therapy use in Hodgkin lymphoma

Radiation therapy assumes a pivotal role in Hodgkin lymphoma management, especially within combined modality therapy. It serves as a cornerstone in early-stage disease and in mitigating high-risk instances of local relapse in advanced stages. Over recent decades, radiation therapy has undergone significant advancements, notably alongside diagnostic imaging improvements, facilitating the reduction of radiation field size and dosage. This progress has notably led to minimized toxicity while upholding treatment efficacy.This comprehensive review extensively evaluates the indications and advancements in radiation therapy for Hodgkin lymphoma, with a primary focus on enhancing treatment efficacy while minimizing radiation-related toxicities. The exploration encompasses a detailed examination of various radiation fields, techniques and delivery modalities employed in Hodgkin lymphoma treatment, including intensity-modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT), and proton therapy. It delves into the intricacies of optimal dose selection and treatment planning strategies aimed at achieving maximal disease control while concurrently minimizing the risk of long-term side effects.

#707 Effectiveness of a personalized approach to the treatment of patients with chronic coronary syndrome with type 2 diabetes and renal dysfunction

Abstract Background and Aims To evaluate the effectiveness of complex personalized treatment of patients with chronic coronary syndrome (CCS) with type 2 diabetes mellitus (T2DM). Method We observed patients with chronic stable angina pectoris III (FC) (Group I, 16) and CV IV FC (Group II, 18) with T2DM who underwent planned stenting of the coronary arteries (SCA). At baseline and after 3 and 6 months, we studied cholesterol, LDL cholesterol and HDL cholesterol, triglycerides (TG), ALT and AST, total bilirubin (TB), polymorphism of the CYP2C19 and 9p21 genes (rs 2383206 and rs 10757272), assessed myocardial viability (ECHOCG, MSCT), an ultrasound of the liver was performed. Against the background of basic therapy (antiplatelet agents, statins, beta blockers, ACE inhibitors), patients received a herbal hepatoprotector. Results Initial lipid parameters in patients with CCS and T2DM: cholesterol—6.9 mmol/l; LDL cholesterol –3.6; HDL cholesterol –1.1; TG –2.5 mmol/l. Parameters of global and regional systolic function were reduced. At the end of observation, lipid content: cholesterol—5.0; LDL cholesterol—2.3; HDL cholesterol –1.18; TG—1.61 mmol/l. Statins and antiplatelet agents were well tolerated, and there were no cases of withdrawal. Enzyme activity (ALT, AST), OB content were within normal values. The genetic studies carried out helped to select the most effective and safe doses of antiplatelet drugs and statins and significantly reduced the risk of complications and drug resistance. The hepatoprotector had a beneficial effect on the condition and function of the liver and improved the tolerability of medications. A personalized approach to the treatment of CCS was carried out taking into account the results of genetic testing with the selection of optimal doses of drugs. When the genotypes of CYP2C19*17 (rs 12248560) CC, ST and TT were distributed, the dose of antiplatelet agents was increased, and when the genotypes of the CYP2C19 gene (rs 4244285) GG, AG and AA were distributed, they were reduced. Assessment of myocardial viability, selection of doses of statins and antiplatelet agents according to individual characteristics, as well as a hepatoprotector increased the effectiveness and safety of treatment. SCA and basic treatment had an impact on the pathogenetic links of CCS, which is especially important in the treatment of patients with concomitant T2DM. Conclusion A personalized approach to the treatment of patients with CCS with T2DM who require SCA, taking into account the functional state and viability of the myocardium, the pharmacogenetic characteristics of the drugs, increases the effectiveness of revascularization, prevents the development of resistance, side effects and complications.

Abstract RF01-01: SERENA-3: A randomized pre-surgical window of opportunity study assessing dose and duration of camizestrant treatment in post-menopausal women with ER-positive, HER2-negative primary breast cancer

Abstract Background Camizestrant, a next-generation oral selective estrogen receptor (ER) degrader (SERD) and pure ER antagonist, has demonstrated statistically significant and clinically meaningful progression-free survival (PFS) benefit over fulvestrant at both 75 and 150 mg once-daily doses in the Phase 2 SERENA-2 (NCT04214288) study in post-menopausal women with ER+ HER2- advanced breast cancer. SERENA-3 (NCT04588298) was established to explore the biological effects of three camizestrant dose levels in post-menopausal women with ER+ HER2- primary breast cancer. Methods Post-menopausal women with ER+ HER2- primary breast cancer scheduled to undergo curative intent surgery were randomly assigned in Stages 1 and 2 to pre-surgical treatment with camizestrant at 75, 150 or 300 mg once daily for 5 to 7 days or, in a sequential Stage 3, randomly assigned to camizestrant at 75 or 150 mg once daily for 12 to 15 days. Image-guided tumor biopsies were accessed as pre-treatment samples, while on-treatment ultrasound-guided tumor biopsies were obtained on the last day of camizestrant treatment. The primary objective was to explore the effect of camizestrant on ER expression by comparison of pre-treatment and on-treatment biopsies as assessed by immunohistochemistry (IHC) H-score. Secondary objectives included assessment of Ki67 and progesterone receptor (PgR) expression, and also of safety and tolerability, with exploratory pharmacodynamic (PD) assessment using other transcriptomic and proteomic technologies. The study was undertaken in 17 centers across 3 countries (Georgia, Mexico and the United Kingdom). Results 135 patients were randomized and received treatment. 76 patients received camizestrant for 5 to 7 days at doses of 75 mg (n=30), 150 mg (n=33), and 300 mg (n=13); 59 received camizestrant for 12 to 15 days at doses of 75 mg (n=30) and 150 mg (n=29). Baseline disease characteristics, and ER, Ki67 and PgR levels were well balanced across arms and stages. Pharmacokinetic (PK) observations in all stages were commensurate with steady-state predictions derived from previous studies. PD data for ER and Ki67 are shown in Table 1. Camizestrant reduced ER H-score by approximately 65% irrespective of dose or duration. While the 75 mg dose reduced Ki67 score to a lesser degree than 150 mg and 300mg after 5–7 days exposure, after 12–15 days exposure 75 and 150 mg reduced Ki76 score to a similar substantial degree (82% reduction). PD results assessed by additional transcriptomics and proteomics assays were concordant with the IHC analyses. No serious adverse events were reported. All treatment-emergent adverse events were grade 1, apart from one patient with a grade 2 visual impairment, and one patient with grade 3 diarrhea. Conclusions SERENA-3 is the first study investigating the effect of multiple dose levels of camizestrant with different treatment durations on ER, Ki67 and PgR expression in post-menopausal women with primary ER+ HER2˗ breast cancer. SERENA-3 demonstrated that the 75 mg dose of camizestrant achieves maximal levels of ER degradation and Ki67 suppression. Together with SERENA-2, this provides strong evidence supporting 75 mg as the optimal dose of camizestrant, including for the early disease setting, and highlights the additive value of a specifically designed multi-dose pre-surgical PD study for optimal dose selection. Table 1 Citation Format: John Robertson, Teimuraz Gogitidze, Zaza Katashvili, Juan Enrique Bargallo Rocha, Ekaterine Arkania, Iain Moppett, Kwok-Leung Cheung, Gia Nemsadze, Maxine Ajimi, Itziar Irurzun-Arana, Justin Lindemann, Teresa Klinowska, Alastair Mathewson, Christopher Morrow, Myria Nikolaou, Giorgi Dzagnidze. SERENA-3: A randomized pre-surgical window of opportunity study assessing dose and duration of camizestrant treatment in post-menopausal women with ER-positive, HER2-negative primary breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr RF01-01.

Justification and Selection of Optimal Doses of Oral Iron in the Treatment of Iron Deficiency without Anemia in Young Women

Justification and Selection of Optimal Doses of Oral Iron in the Treatment of Iron Deficiency without Anemia in Young Women

Establishing an OCD Model in BALB/c Mice Using RU24969: A Molecular and Behavioural Study of Optimal Dose Selection.

Obsessive-compulsive disorder (OCD) is a disabling disease characterized by distressing obsessions and repetitive compulsions. The etiology of OCD is poorly known, and mouse modeling allows to clarify the genetic and neurochemical basis of this disorder and to investigate potential treatments. This study evaluates the impact of the 5-HT1B agonist RU24969 on the induction of OCD-like behaviours in female BALB/c mice (n = 30), distributed across five groups receiving varying doses of RU24969. Behavioural assessments, including marble test, tail suspension test, sucrose preference test, forced swim test, and nestlet shredding test, were conducted. Gene expression and protein quantitation of Gabra1 and serotonin transporter in mouse brain were also performed. Marble-burying behaviour increased significantly at high doses of RU24969 (15-20 mg/kg). The forced swimming test consistently showed elevated values at the same high concentrations, compared to the control. Altered reward-seeking behaviour was indicated by the sucrose preference test, notably at 15 and 20 mg/kg doses of RU24969. Nestlet shredding results did not show statistical significance among the tested animal groups. Gene expression analysis revealed reduced Gabra1 expression with increasing doses of RU, while serotonin transporter was not related to varying doses of RU24969. Western blotting corroborated these trends. The results underscore complex interactions between the serotonin system, GABAergic signaling, and OCD-relevant behaviours and suggest the use of intraperitoneal injection of 15 mg/kg of RU24969 to induce OCD-like behaviour in BALB/c mouse models.

Abstract 2115: Assessing BCL2 protein complex level in peripheral blood mononuclear cells as a surrogate pharmacodynamic biomarker of BCL2 inhibitors in hematological cancers

Abstract In the last decade, cancer therapeutics have adhered to the practice of administering drugs at the maximum tolerated dose (MTD) selected from limited patient cohorts. The emergence of targeted therapies has disrupted this dose selection paradigm, as optimal efficacy may be achievable at lower dose than MTD. Recently, a regulatory agency initiated "OPTIMUS" to redefine the dose selection process, recommending quantitative assessments of drug efficacy in relation to the target protein throughout development and clinical trials. ABT-199 is a protein interaction inhibitor that specifically disrupts the interaction of BCL2 protein. Consequently, the assessment of changes in the level of BCL2 protein complex is necessary to evaluate the ABT-199 efficacy for optimal dose selection. In this study, we adapted the Single-molecule Protein Interaction Detection platform for evaluating pharmacodynamics of BCL2 inhibitors in clinical samples. We assessed the dissociation of two BCL2-related biomarkers, BCL2-BAX and BCL2-BIM, from a model system under various ABT-199 doses. Following one hour treatment with 300 nM of ABT-199, the BCL2-BAX complex dissociated almost by 40%, while 80% of the BCL2-BIM complex remained. The reduction of the BCL2-BIM complex was not changed when extending the treatment for 3 hours, indicating that the BCL2-BAX complex may serve as a more sensitive biomarker for assessing the target engagement of ABT-199. To determine the assay sensitivity, we evaluated the ABT-199 response across different cell numbers and found that 100,000 cells are sufficient for performing the BCL2-BAX assay. Subsequently, we validated the utility of our method in assessing clinical samples, specifically BMMCs and PBMCs. We collected 4 PBMCs and the corresponding BMMCs from hematological cancer patients and treated them with various doses of ABT-199 ex vivo. With 100,000 BMMCs and 1,000,000 PBMCs, we can generate dose-response curves for the BCL2-BAX complex at doses of ABT-199 ranging from 1 to 1,000 nM. To explore the feasibility of employing the BCL2-BAX complex in PBMCs as a surrogate biomarker for assessing ABT-199 engagement with BCL2 in BMMCs, we compared the averaged dose-response curves from 4 PBMCs with that of BMMCs. Remarkably, the two curves showed a coherent dissociation trend, indicating that the biochemical effect of ABT-199 on the BCL2-BAX complex may be conserved across different sample types. Collectively, we have developed a target engagement assay for BCL2 inhibitors by measuring the BCL2-BAX complex. Notably, we observed a consistent dissociation pattern of the BCL2-BAX complex by ABT-199 treatment in both PBMCs and BMMCs. This molecular information offers an alternative way to assess the pharmacodynamics of BCL2 inhibitors, particularly in the case where collecting a series of BMMCs with sufficient amounts may not be feasible. Citation Format: Hongwon Lee, Byungsan Choi, Saem Hong, Yunseo Lee, Tae-Young Yoon, Janghee Woo. Assessing BCL2 protein complex level in peripheral blood mononuclear cells as a surrogate pharmacodynamic biomarker of BCL2 inhibitors in hematological cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2115.

Predictive role of homologous recombination deficiency (HRD) for irinotecan in combination with venadaparib, a novel PARP1/2 inhibitor, as third- or fourth-line treatment in patients with advanced gastric cancer.

380 Background: Tumors with homologous recombination deficiency (HRD), including BRCA and ATM mutations, have shown to predict response to poly (adenosine diphosphate [ADP]–ribose) polymerase (PARP) inhibitors. The associations between treatment efficacy of PARP inhibitor-based regimen and mutations in BRCA (BRCAm) or ATM gene (ATMm) are not well known in previously treated advanced gastric cancer (GC). Combining PARP inhibitor and irinotecan is known to synergize cytotoxicity. The aim of this analysis was to evaluate the association of HRD and efficacy of irinotecan and venadaparib combined, in patients with metastatic GC who had failed at least 2 lines of therapy. Methods: MTT assays were performed in vitro to verify and characterize synergism between venadaparib and SN-38. Data were analyzed using the GraphPad Prism (version 9.5.1) and CompuSyn (version 1.0) software. Patients with at least two prior palliative treatments were enrolled in a multi-national phase Ib trial (NCT04725994). Tumor response was evaluated according to RECIST 1.1. Exploratory genomic analysis was included to assess the correlation between efficacy and HRD. Genomic analysis was conducted using ctDNA (GuardantOMNI Gene Panel version 1.0, Redwood City, CA) on Day 1 pre-dose. Results: In MTT assays, the combination of SN-38 and venadaparib exerted synergistic effect with combination indices (CI) ranging from 0.013 to 0.991 in SNU-638 (BRCA2m), SNU-668 (BRCA1m), AGS (low ATM) and SNU-484 (HR proficient) cells. We observe the synergistic effect between SN-38 and venadaparib remained consistent even at low concentrations of venadaparib (SN-38 IC50; without venadaparib → with 10 nM of venadaparib; SNU-638(1.72→0.28), SNU-668(10.7→1.5), AGS (0.62→0.049), SNU-484(2.25->0.38)). In the dose-finding part of the clinical study, 26 patients were enrolled, 13 had received two prior treatments and 13 had received three prior treatments. At data cut-off, median duration of follow-up (range) was 4.4 (1.3 – 23.7) months. Of the 26 patients enrolled, 5 (1 BRCA2m and 4 ATMm) had HRD (19.2%) and were treated with varying doses of irinotecan and venadaparib. In the five patients with HRD, an objective response rate (ORR) was 60% and median progression-free survival (mPFS) (95% CI) was not reached (1.2–21.5). Of the 26 patients enrolled, 11 received varying doses of venadaparib plus 100 mg/m2 of irinotecan, with an ORR of 36.4% and mPFS (95% CI) of 5.6 (3.5–not reached) months. Conclusions: Venadaparib in combination with irinotecan showed synergistic effect in vitro assays and promising clinical efficacy in the systemic treatment of refractory GC, particularly in patients with HRD. The dose expansion phase of the study is ongoing to investigate the optimal biological dose and patient selection strategies, in a randomized design. Clinical trial information: NCT04725994 .

Late manifestation of autoimmune polyglandular syndrome type 1 with hypoparathyroidism and autoimmune thyroiditis

Autoimmune polyglandular syndrome type 1 (APS 1) is a rare genetic disorder caused by a mutation in the autoimmune regulator AIRE gene. The diagnosis is usually based on the combination of at least two components of the classic triad: mucocutaneous candidiasis, hypoparathyroidism, and primary adrenal insufficiency. Other autoimmune disorders, including thyroid diseases, also occur and may manifest before the primary components. The disease is more likely to manifest during infancy, but some components may develop in adult patients. As the components of the syndrome do not occur simultaneously, verification of the diagnosis is often delayed. A significant challenge in the management of patients with APS 1 is the selection of optimal drug doses due to polypragmasy and the frequent presence of autoimmune disorders and/or candidiasis of the gastrointestinal tract. We present a clinical case of a patient with an atypical course of APS 1, in whom the first endocrine components (hypoparathyroidism and hypothyroidism) were diagnosed in adulthood. This case highlights the phenotypic diversity of APS 1, and the difficulties in selecting therapy when several autoimmune endocrine diseases are combined.

New insights into the role of VKORC1 polymorphisms for optimal warfarin dose selection in Caribbean Hispanic patients through an external validation of a population PK/PD model

Warfarin, an oral anticoagulant, has been used for decades to prevent thromboembolic events. The complex interplay between CYP2C9 and VKORC1 genotypes on warfarin PK and PD properties is not fully understood in special sub-groups of patients. This study aimed to externally validate a population pharmacokinetic/pharmacodynamic (PK/PD) model for the effect of warfarin on international normalized ratio (INR) and to evaluate optimal dosing strategies based on the selected covariates in Caribbean Hispanic patients. INR, and CYP2C9 and VKORC1 genotypes from 138 patients were used to develop a population PK/PD model in NONMEM. The structural definition of a previously published PD model for INR was implemented. A numerical evaluation of the parameter-covariate relationship was performed. Simulations were conducted to determine optimal dosing strategies for each genotype combinations, focusing on achieving therapeutic INR levels. Findings revealed elevated IC50 for G/G, G/A, and A/A VKORC1 haplotypes (11.76, 10.49, and 9.22 mg/L, respectively), in this population compared to previous reports. The model-guided dosing analysis recommended daily warfarin doses of 3–5 mg for most genotypes to maintain desired INR levels, although subjects with combination of CYP2C9 and VKORC1 genotypes * 2/* 2-, * 2/* 3- and * 2/* 5-A/A would require only 1 mg daily. This research underscores the potential of population PK/PD modeling to inform personalized warfarin dosing in populations typically underrepresented in clinical studies, potentially leading to improved treatment outcomes and patient safety. By integrating genetic factors and clinical data, this approach could pave the way for more effective and tailored anticoagulation therapy in diverse patient groups.

Роль вітаміну D при ювенільному ідіопатичному артриті

Considering the role of vitamin D in mineral metabolism and its extracellular effects, including immunomodulation with a tendency to suppress the immune response, there is significant interest in determining its role in developing autoimmune diseases, including juvenile idiopathic arthritis (JIA). Purpose - to determine the role of vitamin D in the development and course of JIA based on a systematic analysis of literature sources over the last 7 years. A search was conducted on PubMed for articles on the role of vitamin D in the development and course of JIA, using combinations of the following terms: “vitamin D” and “juvenile idiopathic arthritis”. The review included scientific publications with available full texts published from January 2017 to August 2023. The analysis results showed significant variations in the level of 25(OH)D among patients with JIA, and the vitamin D status in the majority of JIA patients was not optimal. However, the percentage of patients with suboptimal levels and vitamin D deficiency, according to the majority of studies, was not more significant than in the general population. Nevertheless, a correlation was found between low 25(OH)D concentration and high activity of JIA. Additional vitamin D supplementation did not impact the reduction of JIA activity or the improvement of indicators of bone mineral density. However, some publications emphasize the positive effect of sun exposure in reducing the risk of JIA. Further research is needed to clarify the necessity of additional vitamin D supplementation involving a larger number of patients, standardization, selection of optimal doses, and treatment duration. No conflict of interests was declared by the authors.

Population Pharmacokinetic-Pharmacodynamic Modeling of Neutrophil and Platelet Count for Lower-Intensity Therapy of CPX-351 Combined with Venetoclax in Acute Myeloid Leukemia

Background: Improved survival outcomes and a comparable safety profile with CPX-351 (a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio) vs conventional 7+3 chemotherapy in a pivotal phase 3 trial led to the approval of CPX-351 for newly diagnosed therapy-related acute myeloid leukemia (tAML) or AML with myelodysplasia-related changes (AML MRC) in adults and pediatric (aged ≥1 year) patients in the United States and in adults in Europe. The approved induction dose is 1-2 cycles of CPX-351 100 units/m 2 (daunorubicin 44 mg/m 2 and cytarabine 100 mg/m 2) as a 90-minute intravenous infusion on days 1, 3, and 5 (days 1 and 3 for second induction). In this study, we developed a population pharmacokinetic-pharmacodynamic (PK-PD) model of absolute neutrophil count (ANC) and platelet count to determine the optimal dose for a lower-intensity therapy (LiT) of CPX-351 combined with venetoclax. Methods: The CPX-351 population PK-PD analysis was based on data collected from 3 clinical studies (phase 1 study [NCT00389428; J Clin Oncol 2011; 29(8):979-85];phase 2 study [NCT02238925; Cancer Chemother Pharmacol 2019; 84(1):163-73];phase 3 study [NCT01696084; J Clin Oncol 2018; 36(26):2684-92]) in patients with newly diagnosed high-risk/secondary AML. Venetoclax population PK-PD analysis was based on data from a comprehensive safety analysis of venetoclax monotherapy ( Clin Cancer Res 2018; 24(18):4371-9). ANC and platelet data used in the analysis were from 94 patients for CPX-351 and 272 patients for venetoclax. Generalized semi-mechanistic population PK-PD analyses were performed using non-linear mixed-effects modeling to characterize the time-course of ANC and platelet count following administration of CPX-351 and venetoclax monotherapy. The majority of system parameters were shared across the 2 therapies and a limited number of treatment-specific parameters were estimated by fitting CPX-351 and venetoclax PK time-courses simultaneously. An R Shiny app was developed for the simulation of different dosing regimens with favorable safety profiles to guide optimal dose selection for LiT of CPX-351 combined with venetoclax, assuming the 2 drug effects on ANC and platelet count were additive. Results: The generalized PK-PD model included multi-compartment transit models for ANC and platelet count with separate semi-mechanistic compartments to represent proliferating, maturing, and circulating cells. The model fitted CPX-351 and venetoclax PK-PD data with shared system parameters except for the drug-specific parameter IC 50 (concentration producing 50% of maximal inhibition of cell proliferation). For ANC, the estimated IC 50 values for CPX-351 and venetoclax were 295 μM (relative standard error [RSE]: 8.96%) and 120 μM (RSE: 18.0%), respectively; the shared mean transit time (MTT) estimate for ANC maturation was 66.6 h (RSE: 4.95%), and shared maximal inhibition of cell proliferation (I max) was fixed to 1. For platelet count, the estimated IC 50 values for CPX-351 and venetoclax were 0.0109 μM (RSE: 50.2%) and 16.5 μM (RSE: 8.73%); the shared MTT estimate for platelet maturation was 87.2 h (RSE: 9.01%) and shared I max estimate was 0.313 (RSE: 11.2%). Simulations with different doses of CPX-351 in combination with 400 mg venetoclax were performed. The simulated mean nadir ANC were 2.1, 1.5, 1.1, and 0.6 × 10 9/L for CPX-351 doses of 20, 40, 60, and 100 units/m 2, respectively, when administered on days 1 and 3 and combined with venetoclax 400 mg daily for 28 days. The simulated mean nadir platelet counts were 31.0, 30.3, 30.0, and 29.7 × 10 9/L for CPX-351 doses of 20, 40, 60, and 100 units/m 2, respectively, when administered on days 1 and 3 and combined with venetoclax 400 mg daily for 28 days. Model-based simulated outcomes of ANC and platelet count were consistent with the observed trial data. C onclusions: A generalized semi-mechanistic population PK-PD model was developed to adequately describe the time-courses of ANC and platelet counts in patients with AML following the administration of CPX-351 and venetoclax monotherapy and was used to infer the impact on ANC and platelet count when given in combination. Model-based simulations supported initial dose selection in the phase 1b study of combined CPX-351 LiT plus venetoclax as first-line treatment for patients with AML who are unfit for intensive chemotherapy (NCT04038437).

Oncology Combination Dose-Finding Study Design for Targeted and Immuno-Oncology Therapies.

Combination therapies are often evaluated during the clinical development of oncology investigational agents. A new investigational agent may be combined with one or more approved agent(s) or investigational agent(s). As the initial step to test combination therapies, combination dose escalation of an investigational agent and an approved drug is generally conducted using one of the following designs: sequential design, parallel (staggered) design, healthy participant first-in-human prior to first-in-patient combination escalation, monotherapy lead-in (intra-patient "crossover"), and potentially combination escalation (no monotherapy component). Dose-finding studies for the combinations of two investigational agents may follow similar principles and considerations, and a more conservative approach may be required. A comparison of the characteristics of these designs indicates an efficient design should consider factors including the predicted difference in dose/exposure-response relationships between monotherapy and combination therapy, any potential for pharmacokinetic and pharmacodynamic interactions between the combinatory agents, and the benefit/risk to study participants, etc. In this report, we propose application scenarios for each trial design based on the above considerations and a review of the internal database and published external studies. Generation of robust exposure-response data via an appropriate design will assist the selection of appropriate doses for further assessment to support optimal dose selection as encouraged by the US Food and Drug Administration based on Project Optimus.

A Mechanistic Physiologically-Based Pharmacokinetic Platform Model to Guide Adult and Pediatric Intravenous and Subcutaneous Dosing for Bispecific T Cell Engagers.

Bispecific T cell engagers (Bi-TCEs) have revolutionized the treatment of oncology indications across both liquid and solid tumors. Bi-TCEs are rapidly evolving from conventional intravenous (i.v.) to more convenient subcutaneous (s.c.) administrations and extending beyond adults to also benefit pediatric patients. Leveraging clinical development experience across three generations of Bi-TCE molecules across both liquid and solid tumor indications from i.v./s.c. dosing in adults and pediatric subjects, we developed a mechanistic-physiologically-based pharmacokinetic (PBPK) platform model for Bi-TCEs. The model utilizes a full PBPK model framework and was successfully validated for PK predictions following i.v. and s.c. dosing across both liquid and solid tumor space in adults for eight Bi-TCEs. After refinement to incorporate physiological ontogeny, the model was successfully validated to predict pediatric PKs in 1 month - < 2 years, 2-11 years, and 12-17 years old subjects following i.v. dosing. Following s.c. dosing in pediatric subjects, the model predicted similar bioavailability, however, a shorter time to maximum concentration (Tmax ) for the three age groups compared with adults. The model was also applied to guide the dosing strategy for first generation of Bi-TCEs for organ impairment, specifically renal impairment, and was able to accurately predict the impact of renal impairment on PK for these relatively small-size Bi-TCEs. This work highlights a novel mechanistic platform model for accurately predicting the PK in adult and pediatric patients across liquid and solid tumor indications from i.v./s.c. dosing and can be used to guide optimal dose and dosing regimen selection and accelerating the clinical development for Bi-TCEs.