Higher Drug Exposure Research Articles

Population Pharmacokinetic Simulations for Dose Optimization of Tenofovir Disoproxil Fumarate in HIV-Infected Patients with Moderate-to-Severe Renal Impairment.

Tenofovir disoproxil fumarate (TDF) requires dosage adjustments from the standard 300 mg once daily to every 48-96 h for moderate-to-severe renal impairment to avoid excessive exposure. However, this extended interval can lead to variable drug exposure and inconvenience. This study aimed to utilize the population pharmacokinetic (PPK) models to optimize TDF dosing regimens for HIV-infected patients with renal impairment. A systematic literature search was conducted across PubMed, Cochrane Library, and Scopus databases to identify relevant PPK studies of TDF in HIV-infected patients. From the included studies, the PPK models and associated parameters were extracted. Monte Carlo simulations (n = 2000) were performed to generate concentration-time profiles and derive PK parameters compared against reference ranges. For moderate renal impairment, the TDF 150 mg once-daily regimen achieved cumulative exposure comparable to the approved 300 mg every-other-day regimen. In severe renal impairment, TDF 75-100 mg administered once daily provided similar cumulative exposure as 300 mg every 72-96 h regimen while maintaining daily exposure comparable to the standard dose in patients with normal renal function. The approved extended dosing intervals of 72-96 h exhibited high drug exposure variability, initially resulting in supratherapeutic levels followed by suboptimal levels preceding the subsequent dose administration. In conclusion, administering smaller once-daily doses of TDF maintains consistent daily drug exposure comparable to the standard dose in patients with normal renal function while reducing variability in drug exposure, potentially mitigating the risk of nephrotoxicity. However, additional clinical studies are required to confirm these findings.

Optimization of the betamethasone and dexamethasone dosing regimen during pregnancy: a combined placenta perfusion and pregnancy physiologically based pharmacokinetic modeling approach

BackgroundAntenatal betamethasone and dexamethasone are prescribed to women who are at high risk of premature birth to prevent neonatal respiratory distress syndrome. The current treatment regimens, effective to prevent neonatal RDS, may be suboptimal. Recently, concerns have been raised regarding possible adverse long-term neurological outcomes due to high fetal drug exposures. Data from non-human primates and sheep suggest maintaining a fetal plasma concentration above 1 ng/mL for 48 hours to retain efficacy, while avoiding undesirable high fetal plasma levels. ObjectiveWe aimed to re-evaluate the current betamethasone and dexamethasone dosing strategies to assess estimated fetal exposure and provide new dosing proposals that meet the efficacy target but avoid excessive peak exposures. Study designA pregnancy physiologically-based pharmacokinetic model was used to predict fetal drug exposures. To allow prediction of the extent of betamethasone and dexamethasone exposure in the fetus, placenta perfusion experiments were conducted to determine placental transfer. Placental transfer rates were integrated in the PBPK model to predict fetal exposure and model performance was verified using published maternal and fetal PK data. The verified pregnancy physiologically-based pharmacokinetic models were then used to simulate alternative dosing regimens to establish a model-informed dose. ResultsEx vivo data showed that both drugs extensively cross the placenta. For betamethasone 15.7 ± 1.7% and for dexamethasone 14.4 ± 1.5% of the initial maternal perfusate concentration reached the fetal circulations at the end of the 3-hour perfusion period. Pregnancy physiologically-based pharmacokinetic models that include these ex vivo-derived placental transfer rates, accurately predicted maternal and fetal exposures resulting from current dosing regimens. The dose simulations suggest that for betamethasone intramuscular a dose reduction from 2 dosages 11.4 mg, 24 hours apart, to 4 dosages 1.425 mg, 12 hours apart would avoid excessive peak exposures and still meet the fetal response threshold. For dexamethasone, the dose may be reduced from four times 6 mg every 12 hours to 8 times 1.5 mg every 6 hours. ConclusionA combined placenta perfusion and pregnancy physiologically-based pharmacokinetic modeling approach adequately predicted both maternal and fetal drug exposures of two antenatal corticosteroids. Strikingly, our PBPK simulations suggest that drug doses might be reduced drastically to still meet earlier proposed efficacy targets and minimize peak exposures. We propose the provided model-informed dosing regimens are used to support further discussion on an updated antenatal corticosteroid scheme and design of clinical trials to confirm the effectiveness and safety of lower doses.

Everolimus Mitigates the Risk of Hepatocellular Carcinoma Recurrence after Liver Transplantation.

To obtain long-term data on the use of everolimus in patients who underwent liver transplantation for hepatocellular carcinoma, we conducted a retrospective, single-center analysis of adult recipients transplanted between 2013 and 2021. Patients on everolimus-incorporating immunosuppression were matched with those on tacrolimus using an inverse probability of treatment weighting methodology. Two propensity-matched groups of patients were thus compared: 233 (45.6%) receiving everolimus versus 278 (54.4%) on tacrolimus. At a median (interquartile range) follow-up of 4.4 (3.8) years after transplantation, everolimus patients showed a reduced risk of recurrence versus tacrolimus (7.7% versus 16.9%; RR = 0.45; p = 0.002). At multivariable analysis, microvascular infiltration (HR = 1.22; p < 0.04) and a higher tumor grading (HR = 1.27; p < 0.04) were associated with higher recurrence rate while being within Milan criteria at transplant (HR = 0.56; p < 0.001), a successful pre-transplant downstaging (HR = 0.63; p = 0.01) and use of everolimus (HR = 0.46; p < 0.001) had a positive impact on the risk of post-transplant recurrence. EVR patients with earlier drug introduction (≤30 days; p < 0.001), longer treatment duration (p < 0.001), and higher drug exposure (≥5.9 ng/mL; p < 0.001) showed lower recurrence rates versus TAC. Based on our experience, everolimus provides a reduction in the relative risk of hepatocellular carcinoma recurrence, especially for advanced-stage patients and those with earlier drug administration, higher drug exposure, and longer time on treatment. These data advocate for early everolimus introduction after liver transplantation to reduce the attrition rate consequent to chronic immunosuppression.

Abstract 3296: IK-595, a best-in-class MEK-RAF molecular glue, drives broad and potent anti-tumor activity across RAS-MAPK pathway-altered cancers as a monotherapy and in combination

Abstract Alterations in the RAS/RAF/MEK/ERK pathway are the most common drivers of oncogenesis. Although MEK is a clinically validated cancer target and several MEK inhibitors have been approved by the FDA, their clinical utility has been limited to BRAF V600 mutant cancers and NF1 mutant neurofibromas. We developed the molecular glue, IK-595, a potent inhibitor of the MEK-RAF complex, to overcome the limitations of available MEK inhibitors. IK-595 traps MEK in an inactive complex with all RAF isoforms, as well as mutant forms of BRAF (Class I, II, and III), and blocks RAF-dependent MEK phosphorylation, thereby alleviating CRAF-mediated MEK reactivation that limits the efficacy of approved MEK inhibitors in RAS/RAF-driven tumors. We demonstrate that IK-595 leads to potent and prolonged inhibition of MEK and ERK1/2 phosphorylation in RAS-mutant cancer models. Importantly, IK-595 has a much slower off-rate binding to MEK and retains CRAF longer in an inactive complex with MEK than other MEK/RAF inhibitors, allowing for prolonged target engagement and durable pathway inhibition in RAS/RAF mutant cancer cells. IK-595 exhibits potent single agent activity across a wide range of cancer model indications harboring various RAS/MAPK pathway alterations, including KRAS, NRAS, BRAF and NF1 mutations, and BRAF and CRAF fusions. The benefits of combining IK-595 with inhibitors targeting key resistance mechanisms both within the RAS/MAPK pathway and across parallel survival pathways has also been observed in multiple models. Additionally, IK-595 improved the response of KRAS-driven tumor models to standard of care chemotherapeutic agents, expanding the potential clinical opportunity for IK-595. Key to the design of IK-595 is its PK profile that enables transient high plasma drug exposure and flexible dosing schedules. Intermittent dosing of IK-595 every other day (QOD) or every three days (Q3D) in KRAS-mutant mouse tumor models shows similar efficacy and improved tolerability compared to daily dosing (QD), affording a larger therapeutic window. Preclinical pharmacology studies provide clear guidance to the clinical development plan of IK-595, where flexible dosing schedules, multiple expansion cohorts in RAS/RAF altered patient populations, and combination therapies with mediators of resistance will be explored. IK-595 is a novel MEK-RAF molecular glue that prolongs pathway inhibition, minimizing the potential for resistance, while providing an optimal therapeutic window for patients with RAS/RAF-driven cancer. Citation Format: Eric Haines, Rachel Catterall, Victor De Jesus, Daniel Hidalgo, Jill Cavanaugh, Marta Sanchez-Martin, Joseph D. Manna, Michael Burke, Bin Li, Sarah R. Wessel, Ao Yang, Sergio Santillana, Jeffrey Ecsedy, X. Michelle Zhang, Sabine K. Ruppel. IK-595, a best-in-class MEK-RAF molecular glue, drives broad and potent anti-tumor activity across RAS-MAPK pathway-altered cancers as a monotherapy and in combination [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 3296.

Backflow reduction in local injection therapy with gelatin formulations

The local injection of therapeutic drugs, including cells, oncolytic viruses and nucleic acids, into different organs is an administrative route used to achieve high drug exposure at the site of action. However, after local injection, material backflow and side effect reactions can occur. Hence, this study was carried out to investigate the effect of gelatin on backflow reduction in local injection. Gelatin particles (GPs) and hydrolyzed gelatin (HG) were injected into tissue models, including versatile training tissue (VTT), versatile training tissue tumor-in type (VTT-T), and broiler chicken muscles (BCM), using needle gauges between 23 G and 33 G. The backflow material fluid was collected with filter paper, and the backflow fluid rate was determined. The backflow rate was significantly reduced with 35 μm GPs (p value < .0001) at different concentrations up to 5% and with 75 μm GPs (p value < .01) up to 2% in the tissue models. The reduction in backflow with HG of different molecular weights showed that lower-molecular-weight HG required a higher-concentration dose (5% to 30%) and that higher-molecular-weight HG required a lower-concentration dose (7% to 8%). The backflow rate was significantly reduced with the gelatin-based formulation, in regard to the injection volumes, which varied from 10 μL to 100 μL with VTT or VTT-T and from 10 μL to 200 μL with BCM. The 35 μm GPs were injectable with needles of small gauges, which included 33 G, and the 75 μm GPs and HG were injectable with 27 G needles. The backflow rate was dependent on an optimal viscosity of the gelatin solutions. An optimal concentration of GPs or HG can prevent material backflow in local injection, and further studies with active drugs are necessary to investigate the applicability in tumor and organ injections.

Use of Exposure Data to Establish Causality in Drug-Adverse Event Relationships: An Example with Desvenlafaxine.

Causality algorithms help establish relationships between drug use and adverse event (AE) occurrence. High drug exposure leads to a higher likelihood of an AE being classified as an adverse drug reaction (ADR). However, there is a knowledge gap regarding what concentrations are predictive of ADRs, as this has not been systematically studied. In this work, the Spanish Pharmacovigilance System (SEFV) algorithm was used to define the relationship between the AE occurrence and drug administration in 178 healthy volunteers participating in five desvenlafaxine single-dose clinical trials, a selective serotonin and norepinephrine reuptake inhibitor that may cause dizziness, headache, nausea, dry mouth, constipation and hyperhidrosis. Eighty-three subjects presented 172 AEs that were classified as possible (101), conditional (31), unrelated (24) and probable (16). AUC∞ and Cmax were significantly higher in volunteers with vs. without ADRs (5981.24 ng·h/mL and 239.06 ng/mL and 4770.84 ng·h/mL and 200.69 ng/mL, respectively). Six of 19 subjects with conditional AEs with an SEFV score of 3 points presented an AUC∞ ≥ 6500 ng·h/mL or a Cmax ≥ 300 ng/mL (i.e., above percentile 75) and were summed one point on their SEFV score and classified as "possible" (4 points), improving the capacity of ADR detection.

Abstract B155: IK-595, a best-in-class MEK-RAF complex inhibitor, drives broad and potent anti-tumor activity in RAS/RAF-driven tumors

Abstract Alterations in the RAS/RAF/MEK/ERK pathway are the most common drivers of oncogenesis. Although MEK is a clinically validated cancer target and several MEK inhibitors have been approved by the FDA, their clinical utility has been limited to BRAF V600 mutant cancers and NF1 mutant neurofibromas. We developed IK-595, a potent inhibitor of the MEK-RAF complex, to overcome the limitations of available MEK inhibitors. IK-595 traps MEK in an inactive complex with all RAF isoforms and blocks RAF-dependent MEK phosphorylation, thereby alleviating CRAF-mediated MEK reactivation that hinders the efficacy of approved MEK inhibitors in RAS/RAF-driven tumors. We demonstrate that IK-595 leads to potent and prolonged inhibition of MEK and ERK1/2 phosphorylation, in KRAS-mutant cancer and NRAS-mutant melanoma models. In addition to trapping all three RAF isoforms, IK-595 stabilizes the interaction of MEK with BRAF Class I, II, and III mutant proteins. This delays the onset of known resistance mechanisms to other MAPK pathway targeting agents, such as CRAF-mediated pathway reactivation and receptor tyrosine kinase upregulation and/or activation. Importantly, IK-595 has a much slower off-rate binding to MEK and retains CRAF longer in an inactive complex with MEK than other MEK/RAF inhibitors allowing for more prolonged target engagement and durable pathway inhibition in RAS/RAF mutant cancer cells. Moreover, CRAF-ARAF heterodimerization, which is detected in type II pan-RAF inhibitor-treated KRAS mutant cells as an established resistance mechanism, is not observed upon IK-595 treatment. IK-595 exhibits potent signal agent activity across a wide range of cancer models harboring various RAS/RAF alterations, including lung, pancreatic, colorectal cancer (CRC), melanoma, AML, and others. Strong synergy with inhibitors targeting multiple key mechanisms, both within the RAS/MAPK pathway and across parallel survival pathways, has also been observed in multiple models. Key to the design of IK-595 is its PK profile that enables transient high plasma drug exposure and flexible dosing schedules. Intermittent dosing of IK-595 every other day (QOD) or every three days (Q3D) in KRAS mutant mouse tumor models shows similar efficacy and improved tolerability compared to daily dosing (QD), affording a larger therapeutic window. Preclinical pharmacology studies provide clear guidance to the clinical development plan of IK-595, where flexible dosing schedules and multiple expansion cohorts in RAS/RAF altered patient populations will be explored. IK-595 is a novel MEK-RAF complex inhibitor that prolongs pathway inhibition, minimizing the potential for resistance, while providing an optimal therapeutic window for patients with RAS/RAF-driven cancer. Citation Format: Eric Haines, Rachel Catterall, Victor De Jesus, Bin Li, Sarah R Wessel, Jill Cavanaugh, Michael Burke, Joseph D Manna, Okzana Zavidij, Ao Yang, Lan Xu, Sergio Santillana, Jeffrey Ecsedy, X. Michelle Zhang, Sabine K Ruppel. IK-595, a best-in-class MEK-RAF complex inhibitor, drives broad and potent anti-tumor activity in RAS/RAF-driven tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B155.

Endogenous Protein C Activation with AB002 Improves Outcomes in a Rat Model of Acute Ischemic Stroke

Background: The hemorrhagic side-effects of current thrombolytic agents limit their usefulness to a small subset of acute ischemic stroke patients. An early, effective, and hemostatically safe antithrombotic/neuroprotectant in addition to standard of care could improve outcomes. AB002 (E-WE thrombin) is an engineered recombinant thrombin analog (W215A/E217A) that activates cytoprotective and antithrombotic endogenous protein C on intravascular surfaces without any measurable procoagulant activity. In renal failure patients undergoing hemodialysis, AB002 treatment reduced dialyzer clotting without increasing markers of hemostasis impairment or coagulation (NCT03963895). Preclinical studies also showed that AB002 exhibits potent antithrombotic/thrombolytic effects in a non-human primate model of acute vascular graft thrombosis, as well as reduces infarct size and improves outcomes in an experimental acute myocardial ischemia-reperfusion model in mice. Aims: Here, we evaluated whether neuroprotective effects of AB002 can be observed following middle cerebral artery occlusion-recanalization (MCAO-R) in rats. Methods: The local animal care and use committee approved all studies. 8 to 9-week-old male rats (275-377 g) were anesthetized under isoflurane and a small laser-Doppler probe was affixed to the skull to monitor cortical perfusion and verify vascular occlusion and reperfusion. A silicone-coated 4-0 nylon monofilament was inserted into the right internal carotid artery (ICA) via the external carotid artery (ECA) until the laser-Doppler signal dropped to &amp;lt; 30 % of baseline. To evaluate the effect of AB002 on outcomes, rats (n = 4/ group) were treated with 25 µg/kg (0.25 mL/kg; i.v.) or saline placebo, administered 30 min after induction of ischemia. Since prolongation of the activated partial plasminogen time (aPTT) is a pharmacologic effect of high dose drug exposure, a 0.45 mL blood sample was collected at 20 min post treatment from the right jugular vein, processed to plasma and frozen for subsequent aPTT evaluation. At 90 min, the filament was removed, the surgical incisions were sutured closed and postoperative animals were monitored during recovery. Neurological performance scores and weight were assessed daily for 4 days. Rats were sacrificed on day 7 post-surgery and infarct size was measured using 2,3,5-triphenyltetrazolium chloride (TTC) staining. To account for the effect of edema, the infarcted area was estimated indirectly by subtracting the non-infarcted area in the ipsilateral hemisphere from the contralateral hemisphere and expressing infarct volume as a percentage of contralateral hemisphere. APTT was measured in duplicate using a KC-4 coagulometer. All analyses were performed by researchers blinded to treatment. Results: Compared to placebo, rats that received AB002 exhibited less ischemic damage, evidenced by a statistically significant reduction in infarct volume of the cortex (32.3% versus 8.9%, P &amp;lt; 0.05) and hemisphere (28.0% versus 9.8%, P &amp;lt; 0.01). In addition, rats had better neurological scores and greater weight gains during recovery following treatment with AB002, compared to placebo. Mean aPTT values were higher in AB002 treated rats compared to placebo (34 ± 2.2 s versus 21 ± 1.6 s), confirming drug exposure. Conclusions: Treatment with AB002 during ischemia reduced infarct volume and improved outcomes in the rat experimental stroke model. Considering its neuroprotective and antithrombotic properties, we propose that early treatment with AB002 may confer outcome benefit for patients experiencing acute thrombotic emergencies.

Discovery of BCL-XL Heterobifunctional Degrader with Potentially Improved Therapeutic Window and Minimal Platelet Toxicity for Hematological Malignancies

Background In hematologic malignancies, apoptosis evasion promotes tumor formation/progression and is driven by the overexpression of anti-apoptotic proteins, including BCL-2 and BCL-XL. BCL-2-targeting small molecule inhibitor venetoclax won FDA approval for chronic lymphocytic leukemia and acute myeloid leukemia. Interests in developing BCL-XL-selective inhibitors arise as BCL-XL overexpression is implicated in venetoclax resistance. However, these efforts failed in clinical development due to dose-limiting thrombocytopenia, as platelets (PLT) also depend on BCL-XL for survival. To mitigate this on-target toxicity, a degrader strategy has been proposed, whereby BCL-XL protein can be selectively degraded by the von Hippel-Lindau protein (VHL) E3 ligase in tumor cells, but not in PLT which minimally express VHL. The first such BCL-XL degrader (DT2216) was developed and is now in early clinical trials. Despite negligible PLT toxicity in vitro, DT2216 was still toxic to PLT in vivo. We reasoned that since earlier BCL-XL degraders used strong BCL-XL inhibitor as warhead, e.g. the warhead for DT2216 is ABT263, they could readily bind to and inhibit BCL-XL in PLT causing thrombocytopenia. Warhead-containing metabolites could also form and behave as an inhibitor, exacerbating PLT toxicity in vivo. Utilizing our artificial intelligence-empowered neoDegrader platform, which accurately characterizes the landscape of the degrader-mediated, metastable interactions between E3 and its target protein, we were able to computationally design molecules that were relatively weak BCL-XL binders but could maintain the ternary complex at metastable states. Herein, we report the preclinical profile of the lead candidate NXD02. Methods We assessed the binding affinity of NXD02 to BCL-XL by surface plasmon resonance. We conducted flow cytometry to quantify NXD02-mediated BCL-XL protein degradation and apoptotic effects in MOLT4 cells. We also quantified the anti-proliferative activity of NXD02 by CellTiter-Glo assay. We measured protein level changes of apoptosis markers by western blot. We simultaneously determined plasma concentration of NXD02 and PLT at various time points following a single injection of NXD02 in rodents and monkeys. Finally, we evaluated the anti-tumor activity of NXD02 in an orthotopicMOLT4-luc mouse xenograft (CDX) model by bioluminescence imaging. Results The binding affinity of NXD02 to BCL-XL was &amp;gt; 40-fold weaker than that to DT2216 (K D 28.7 vs 0.6 nM). Despite this, NXD02 strongly degraded BCL-XL protein (DC 50 6.6 nM) with no obvious hook effect, which was more potent than DT2216 (DC 50 17.4 nM) in MOLT4 cells. At 100 nM, NXD02 markedly increased levels of active caspase 3 and cleaved PARP, which was consistent with evidence of massive apoptosis. This was translated to a potent anti-proliferative effect comparable to DT2216 (IC 50 27.8 vs 42.7 nM). NXD02 did not affect PLT viability up to a concentration of 10 μM in vitro. Notably, a single dose of NXD02 at 10 mg/kg i.v. achieved an exposure &amp;gt;4-fold than that of DT2216 (dose-normalized AUC 68.5 vs 15.3 μg*h/mL/(mg/kg)) in CD1 mice, while producing similar levels of peak PLT reduction (58% vs 65%) at ~24 h, which recovered by day 3. Comparable or less PLT reduction was also observed in rats (64% vs 66%) at 15 mg/kg and in cynomolgus monkeys (63% for NXD02 vs 87% for DT2216) at 3 mg/kg, all of which fully recovered by days 5-6, supporting the possibility for weekly dosing. Furthermore, NXD02 demonstrated stronger in vivo anti-tumor activity than DT2216 in a CDX model. Weekly i.v. dosing of NXD02 at 3 and 10 mg/kg achieved 80% and 100% tumor growth inhibition (TGI) by day 28 respectively, as compared to 36% TGI for DT2216 at 10 mg/kg. There was no significant body weight loss for all groups. Conclusions We have discovered a structurally-novel, VHL-mediated, heterobifunctional BCL-XL degrader NXD02 with “Weak Inhibitor, Strong Degrader” properties. NXD02 displayed, at the same dose, a much higher drug exposure, better anti-tumor activity and comparable platelet toxicity profile in vivo than the most advanced BCL-XL degrader DT2216. The results suggest that NXD02 may have a more favorable safety margin. In vitro toxicity profiling of NXD02 including Ames test and safety panel revealed no concerns so far. In vivo safety assessment is ongoing for NXD02 as a promising candidate for clinical development in liquid and potentially select solid tumors.

Local and distant response to intratumoral immunotherapy assessed by immunoPET in mice

BackgroundDespite the promising efficacy of immune checkpoint blockers (ICB), tumor resistance and immune-related adverse events hinder their success in cancer treatment. To address these challenges, intratumoral delivery of immunotherapies has...

SAT471 Hearing-Related Adverse Events in Teprotumumab Oncology Clinical Trials

Abstract Disclosure: T.J. Smith: Consulting Fee; Self; Horizon Therapeutics plc, Viridian, Lundbeck. Other; Self; US patents covering the use of IGF-1 receptor inhibitors in TED which are held by UCLA and the Lundquist Institute. Q. Fu: Employee; Self; Horizon Therapeutics plc. Stock Owner; Self; Horizon Therapeutics plc. R.J. Holt: Employee; Self; Horizon Therapeutics plc. Stock Owner; Self; Horizon Therapeutics plc. Background: Teprotumumab was originally developed for the treatment of a variety of cancers; however, the development program was terminated due to lack of efficacy although no major safety concerns were observed. Teprotumumab was eventually approved by the FDA for the treatment of thyroid eye disease (TED). Hearing-related adverse events (AEs) with insulin-like growth factor-I receptor inhibitors have been reported in clinical trials. Methods: The incidence and severity of hearing-related AEs, as classified by the Medical Dictionary for Regulatory Activities, in teprotumumab-treated patients (N=633) receiving monotherapy (N=362) or in combination with anti-neoplastic therapy (N=271) from oncology clinical trials was evaluated. The relation of events to teprotumumab, severity, and drug exposure up to time of each event was calculated. Results: A total of 8 oncology clinical trials were included with 8.1% (N=51) of patients reporting any Ear and Labyrinth Disorder AEs, and 2.1 % (N=13) reporting events considered teprotumumab-related by the investigators. 3.8% of patients (N=24) reported hearing impairment or tinnitus-related events with 1.3% (N=8) ascribed to teprotumumab. Approximately 80% of reported AEs were considered mild, with Ear Discomfort being the most common. More than half of AEs were reported within 60 days of therapy initiation. The majority of patients (74%) had teprotumumab exposures consistent with the current FDA-recommended dosing regimen of teprotumumab for TED (150 mg/kg). Findings were consistent regardless of relatedness to teprotumumab or whether given as monotherapy or in combination with anti-neoplastic agents (some of which have been reported to cause hearing-related events). Of the teprotumumab-ascribed hearing AEs, two were considered moderate (deafness and hypoacusis) and one as severe (bilateral deafness). The moderate hypoacusis event occurred in a patient exposed to nearly twice the total dose of the recommended regimen of teprotumumab for TED. The severe event occurred in a patient exposed to almost 7 times the expected exposure with the recommended TED dosing. Conclusions: Hearing-related AE type and incidence were similar in patients who received teprotumumab as monotherapy or in combination with other agents in this sizeable oncology trial program. The most severe events reported were at higher drug exposures than used in the TED clinical trials. The types of AEs and incidence were also comparable to those reported in the TED clinical trial program and as reported in the current FDA-approved prescribed labeling for teprotumumab in the United States. Presentation Date: Saturday, June 17, 2023

Case-control matching-guided exposure-efficacy relationship for avelumab in patients with urothelial carcinoma.

Exposure-response (E-R) analyses are an integral component of understanding the benefit/risk profile of novel oncology therapeutics. These analyses are typically conducted using data from the treatment arm to characterize the relationship between drug exposure (low vs. high) and efficacy or safety outcomes. For example, outcomes of patients with lower exposure in the treatment arm (e.g., Q1) might be compared to outcomes of those with higher drug exposure (Q2, Q3, and Q4). Outcomes from the lowest exposure quartile may be also compared to the control arm to evaluate whether the Q1 subgroup derived clinical benefit. However, the sample size and the distribution of patient baseline characteristics and disease risk factors are not balanced in such a comparison (Q1 vs. control), which may bias the analysis and causal interpretation of clinical benefit in the Q1 subgroup. Herein, we report the use of case-control matching to account for this bias and better understand the E-R relationship for avelumab in urothelial carcinoma, a PD-L1 inhibitor approved for the treatment of several cancers. Data from JAVELIN-100 was utilized which is a phase III study of avelumab in first-line maintenance treatment in patients with urothelial carcinoma; this clinical study demonstrated superiority of avelumab versus best-supportive care leading to approval in the United States, Europe, and other countries. A post hoc case-control matching method was implemented to compare the efficacy outcome between Q1 avelumab subgroup and matched patients extracted from the control arm with similar baseline characteristics, which showed a clinically relevant difference in overall survival in favor of the Q1 avelumab subgroup. This analysis demonstrates the importance of accounting for imbalance in important baseline covariates when comparing efficacy outcomes between subgroups within the treatment arm versus the control arm.

Population pharmacokinetics of apixaban in a real-life hospitalized population from the OptimAT study.

This study aimed to characterize apixaban pharmacokinetics (PKs) and its variability in a real-world clinical setting of hospitalized patients using a population PK (PopPK) approach. Model-based simulations helped to identify factors that affect apixaban exposure and their clinical significance. A classic stepwise strategy was applied to determine the best PopPK model for describing typical apixaban PKs in hospitalized patients from the OptimAT study (n = 100) and evaluating the associated variability and influencing factors. Apixaban exposure under specific conditions was assessed using the final model. A two-compartment model with first-order absorption and elimination best described the data. The developed PopPK model revealed a major role of renal function and a minor role of P-glycoprotein phenotypic (P-gp) activity in explaining apixaban variability. The final model indicated that a patient with stage 4 chronic kidney disease (creatinine clearance [CLcr] = 15-29 mL/min) would have a 45% higher drug exposure than a patient with normal renal function (CLcr >90 mL/min), with a further 12% increase if the patient was also a poor metabolizer of P-gp. A high interindividual variability in apixaban PKs was observed in a real-life setting, which was partially explained by renal function and by P-gp phenotypic activity. Target apixaban concentrations are reached under standard dosage regimens, but overexposure can rapidly occur in the presence of cumulative factors warranting the development of a predictive tool for tailoring apixaban exposure and its clinical utility in at-risk patients.

A novel bispecific antibody as an immunotherapeutic agent in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains one of the most common and highly fatal malignancies in humans worldwide with increasing prevalence and limited therapeutic options. For many decades, many researchers have attempted to find effective curative methods for HCC and great strides have been made. GPC3 is overexpressed in HCC, but not in normal liver, making it a rational immunotherapeutic target for HCC. GC33, a humanized mAb directed against GPC3, is a safe and well-tolerated therapy choice for patients with HCC, which tested in a phase I trial in advanced HCC patients. Phase II trials of GC33 to evaluate its efficacy and safety in advanced or metastatic HCC, showed no significant differences in overall survival and progression-free survival compared with the placebo. Retrospective analysis indicates that high drug exposure and high CD16 expression may contribute to the clinical efficacy of GC33. Chugai Pharmaceutical has restarted its Phase I trial of GC33, continuing to explore its clinical value targeting GPC3 in solid tumors. To enhance the antitumor potency of GC33, we designed a GPC3/CD16A bispecific antibody (QDEB). In this study, we obtained QDEB at high purity and assessed its effectiveness in the therapy of HCC compared with GC33. In vitro cytotoxicity assays and in vivo experiments demonstrated that QDEB could enhance anti-tumor efficacy compared with GC33. CD16A activation and increased cytokines release were associated with higher anti-tumor activity. In conclusion, this bispecific antibody may possibly help develop new therapeutic strategies for HCC and develop new treatment options in the future.

Single-dose pharmacokinetics and lung function of nebulized niclosamide ethanolamine in sheep

PurposeNiclosamide is approved as an oral anthelminthic, but its low oral bioavailability hinders its medical use requiring high drug exposure outside the gastrointestinal tract. An optimized solution of niclosamide for nebulization and intranasal administration using the ethanolamine salt has been developed and tested in a Phase 1 trial. In this study we investigate the pulmonary exposure of niclosamide following administration via intravenous injection, oral administration or nebulization.MethodsWe characterized the plasma and pulmonary pharmacokinetics of three ascending doses of nebulized niclosamide in sheep, compare it to intravenous niclosamide for compartmental PK modelling, and to the human equivalent approved 2 g oral dose to investigate in the pulmonary exposure of different niclosamide delivery routes. Following a single-dose administration to five sheep, niclosamide concentrations were determined in plasma and epithelial lining fluid (ELF). Non-compartmental and compartmental modeling was used to characterize pharmacokinetic profiles. Lung function tests were performed in all dose groups.ResultsAdministration of all niclosamide doses were well tolerated with no adverse changes in lung function tests. Plasma pharmacokinetics of nebulized niclosamide behaved dose-linear and was described by a 3-compartmental model estimating an absolute bioavailability of 86%. ELF peak concentration and area under the curve was 578 times and 71 times higher with nebulization of niclosamide relative to administration of oral niclosamide.ConclusionsSingle local pulmonary administration of niclosamide via nebulization was well tolerated in sheep and resulted in substantially higher peak ELF concentration compared to the human equivalent oral 2 g dose.

#2989 SELECTIVE RENAL DISPOSITION OF THE CALCINEURIN INHIBITORS VOCLSOPORIN, CYCLOSPORINE, AND TACROLIMUS

Abstract Background and Aims The calcineurin inhibitors (CNI) cyclosporine (CSA) and tacrolimus (TAC) were revolutionary immunosuppressants when first introduced for solid organ transplantation in the 1980s. Voclosporin (VCS), a novel CNI, recently became the first oral therapy approved in the United States, Great Britain, and Europe for the treatment of active lupus nephritis based on positive results from Phase 2 and 3 clinical trials. Unlike CSA and TAC, VCS has demonstrated a consistent pharmacokinetic and pharmacodynamic profile, eliminating the need for therapeutic drug monitoring. Further, VCS is associated with a more favorable metabolic profile and has not been associated with electrolyte disturbances. Emerging evidence indicates small molecule therapeutics may display differential disposition within organ tissues. This suggests that CNIs may be differentially distributed and retained in the kidney, potentially explaining the difference in their efficacy and safety profiles. To evaluate renal disposition of CSA, TAC, and VCS, we assessed in mice and humans the disposition of each CNI in the kidney relative to its systemic drug exposure. Method Single 30 mg/kg doses of CSA, TAC and VCS were administered intravenously to mice. Following intravenous administration, kidneys were collected at 15 minutes, 30 minutes, 1 hour and 2 hours, flash frozen in liquid nitrogen, and stored at −20 °C until sectioning. Sections of 10 μm kidney tissue were mounted on indium tin oxide coated glass slides. Matrix of 10 mg/mL α-Cyano-4-hydroxycinnamic acid in 85% acetonitrile/13% ethanol + 2% water + 0.1% trifluoroacetic acid was sprayed on the tissue using an HTX tissue sprayer, dried for 10 minutes in the vacuum, and subjected to Matrix-assisted Laser Desorption and Ionization Mass Spectrometry Imaging (MALDI-MSI). The systemic and renal clearance in humans of CSA and TAC were obtained from the literature; pharmacokinetic data on VCS was obtained from data on file. Renal secretion of each drug was compared to its expected passive filtration based on glomerular filtration rate (GFR), fraction unbound in plasma (fu), and respective systemic drug exposure. Results MALDI-MSI demonstrated significantly higher concentrations of drug and more diffuse tissue disposition of CSA in mouse kidney compared to VCS (Figure 1). CSA was retained in all kidney tissues up to 2 hours post-administration. Higher concentrations and more diffuse disposition of TAC was also noted compared to VCS at 15 and 30 minutes; TAC was distinctively retained in the cortex and medulla. VCS had moderate distribution in the cortex and was rapidly excreted with low levels of drug present in the kidney after 1 hour. According to published data, CSA has a measured renal clearance of 1.48 mL/min in healthy human subjects, representing approximately 10% of expected passive filtration of 12.5 mL/min (Table 1). TAC has a renal clearance of 0.014 mL/min representing &amp;lt;2% of expected passive filtration of 1.25 mL/min. VCS has a renal clearance of 7.82 mL/min representing approximately 200% of its expected passive filtration rate of 3.75 mL/min. Conclusion MALDI-MSI revealed differential retention and distribution of CSA, TAC and VCS in mice, consistent with their respective renal clearances in humans. Higher drug exposure and &amp;gt;90% renal reabsorption was observed for both CSA and TAC in this study, whereas the renal handling of VCS suggested a significant component of tubular secretion. The higher rate of secretion and lower overall exposure of kidney tissue to VCS may be associated with an improved safety profile when compared to the more diffuse distribution and greater renal retention of CSA and TAC.

A phase I trial of the pan-ERBB inhibitor neratinib combined with the MEK inhibitor trametinib in patients with advanced cancer with EGFR mutation/amplification, HER2 mutation/amplification, HER3/4 mutation or KRAS mutation

PurposeAberrant alterations of ERBB receptor tyrosine kinases lead to tumorigenesis. Single agent therapy targeting EGFR or HER2 has shown clinical successes, but drug resistance often develops due to aberrant or compensatory mechanisms. Herein, we sought to determine the feasibility and safety of neratinib and trametinib in patients with EGFR mutation/amplification, HER2 mutation/amplification, HER3/4 mutation and KRAS mutation.MethodsPatients with actionable somatic mutations or amplifications in ERBB genes or actionable KRAS mutations were enrolled to receive neratinib and trametinib in this phase I dose escalation trial. The primary endpoint was determination of the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT). Secondary endpoints included pharmacokinetic analysis and preliminary anti-tumor efficacy.ResultsTwenty patients were enrolled with a median age of 50.5 years and a median of 3 lines of prior therapy. Grade 3 treatment-related toxicities included: diarrhea (25%), vomiting (10%), nausea (5%), fatigue (5%) and malaise (5%). The MTD was dose level (DL) minus 1 (neratinib 160 mg daily with trametinib 1 mg, 5 days on and 2 days off) given 2 DLTs of grade 3 diarrhea in DL1 (neratinib 160 mg daily with trametinib 1 mg daily). The treatment-related toxicities of DL1 included: diarrhea (100%), nausea (55.6%) and rash (55.6%). Pharmacokinetic data showed trametinib clearance was significantly reduced leading to high drug exposures of trametinib. Two patients achieved stable disease (SD) ≥ 4 months.ConclusionNeratinib and trametinib combination was toxic and had limited clinical efficacy. This may be due to suboptimal drug dosing given drug–drug interactions.Trial registration ID: NCT03065387.

Degradable Hydrogel for Sustained Localized Delivery of Anti-Tumor Drugs

Disadvantages of systemically administered immunomodulatory anti-tumor therapies include poor efficacy and high toxicity. Direct intratumoral injection of a drug is often associated with rapid efflux from the site of administration, thus reducing local exposure and therapeutic efficacy, while potentially increasing systemic adverse events. To address this, a sustained release prodrug technology was developed using a transient conjugation (TransConTM) technology to provide long-term high local drug exposure after injection in the tumor while minimizing systemic exposure. TransCon technology for systemic delivery is clinically validated, with multiple compounds in late-stage clinical development and approval of a once-weekly growth hormone for pediatric growth hormone deficiency. As a further application of this technology, this report describes the design, preparation, and functional characterization of hydrogel microspheres as insoluble, yet degradable carrier system. Microspheres were obtained after reaction of PEG-based polyamine dendrimers and bifunctional crosslinkers. Resiquimod, a TLR7/8 agonist, and axitinib, a vascular endothelial growth factor tyrosine kinase inhibitor, were chosen as anti-cancer drugs. The drugs were covalently attached to the carrier by linkers, which released the drugs under physiological conditions. Essentially all resiquimod or axitinib was released over weeks before physical degradation of the hydrogel microsphere was observed. In summary, TransCon Hydrogel technology allows localized sustained-release drug delivery for cancer therapy enabling high local drug concentrations while at the same time ensuring low systemic drug exposure over weeks with a single injection, which may improve the therapeutic index and improve efficacy, while minimizing systemic adverse events. A hydrogel prodrug of resiquimod, TransCon TLR7/8 agonist, is currently being investigated in clinical trials of patients with solid tumors (NCT04799054).

Abstract 4020: HMPL-760 is a highly potent and selective reversible BTK inhibitor, targeting BTK and BTKC481S in B-cell malignancies

Abstract Introduction: Bruton’s tyrosine kinase (BTK), a member of the Tec family, plays a crucial role in signaling through B-cell receptor (BCR). BTK inhibition blocks BCR signals and prevents B-cell activation and growth. First-generation BTK inhibitors such as ibrutinib covalently binds to a cysteine residue (C481) of BTK. Their most frequent acquired resistance is the development of a serine mutation in the binding site (C481S). Next generation BTK inhibitors such as LOXO-305 and ARQ 531 are being developed to overcome this resistance to first-generation inhibitors. Methods: HMPL-760 was tested in biochemical assays using recombinant human wild type (WT) and C481S mutant BTKs. Its selectivity was carried out using Eurofins Cerep KinaseProfilerTM panel. Cellular activity of HMPL-760 was evaluated in HEK293 cells stably transfected with BTKWT or BTKC481S, and other tumor cell lines, which are either human diffuse large B cell lymphoma (DLBCL) or mantle cell lymphoma (MCL) cell lines. The in vivo antitumor activity and PKPD correlation of HMPL-760 was studied in HBL-1 xenograft mouse models bearing BTKWT or BTKC481S respectively. Results: In biochemical assays, HMPL-760 strongly inhibits BTK kinase activities towards wild-type BTK (BTKWT) and C481S mutant (BTKC481S), and binds to BTK in a reversible way. HMPL-760 demonstrates high selectivity in a panel containing 413 kinases. In cellular assays, HMPL-760 displays strong anti-proliferative activities in B-cell lymphoma cells (TMD-8, OCI-LY10, REC-1, HBL-1 and HBL-1-BTKC481S) harboring either BTKWT or BTKC481S (GI50: 0.0015-0.046 μM). In human whole blood assay, HMPL-760 inhibits activation of B-cells at nanomolar concentrations measured by inhibition of immunoglobulin-induced CD69 expression in CD19+cells. HMPL-760 shows ≥ 10-fold inhibitory potency than ARQ 531 in both BTKWT and BTKC481S cells, and ~3-fold higher inhibitory potency than that of LOXO-305 in BTKC481S cells. In cellular assay by detecting p-BTK after compound washout, HMPL-760 maintains a longer duration of target inhibition than LOXO-305 in both BTK wild type (HBL-1) and BTK mutant (HBL-1-BTKC481S) cell lines. HMPL-760 displays dose-dependent antitumor efficacy in multiple human B cell lymphoma xenograft models in mice when orally administered at 3~50 mg/kg once daily. Complete tumor regression occurs in most of the tested models at the high dose levels. HMPL-760 shows much stronger antitumor efficacy than LOXO-305 and ARQ 531 at similar dose level, which may be associated with HMPL-760’s higher drug exposures and more sustainable inhibition on BTK phosphorylation in the tumor tissues. Conclusion: HMPL-760 is a reversible, selective, highly potent, BTK inhibitor targeting both BTKWT and BTKC481S. The first-in-human Phase 1 clinical trials of HMPL-760 are under way in patients with r/r B-NHL (NCT05190068, NCT05176691). Citation Format: Linfang Wang, Junqing Liang, Zhihu Gao, Jia Hu, Weigang He, Xianwen Yang, Fangfang Mao, Wei Zhang, Ying Yu, Qihang Zhang, Na Yang, Chun Zhang, Jian Wang, Yu Cai, Xiong Li, Weiguo Qing, Guangxiu Dai, Yongxin Ren, Michael Shi, Weiguo Su. HMPL-760 is a highly potent and selective reversible BTK inhibitor, targeting BTK and BTKC481S in B-cell malignancies. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4020.

Abstract 2929: Modular peptide cargo delivery by targeting CD40 enables ligandome driven, precision immunotherapy via the Adaptable Drug Affinity Conjugate (ADAC™) technology

Abstract Agonistic anti-CD40 therapy has shown impressive efficacy in preclinical murine models, models inert to toxicity of high systemic drug exposure. Clinical data consist of pharmacodynamic responses reported as non-specific cytokine release, transient drop of CD40-expressing cells in blood and induction of co-stimulatory ligands/receptors on antigen-presenting cells, but so far clinically meaningful efficacy data on monotherapy use is lacking. Clinical data also indicate a bell-shaped dose-response curve, with excessive immune activation leading to immune exhaustion when combined with check-point inhibitors[1]. Intratumoral route of administration, bispecific antibodies for tumor drug localization or Antibody-Drug Conjugates (ADCs) carrying antigenic cargo are or have been assessed, but have associated clinical utility enigmas. Herein we present a novel solution ensuring modular peptide delivery along with an efficient T cell priming strategy; a bivalent anti-CD40 agonistic antibody equipped with a peptide-binding single chain variable fragment (scFv) that binds a short peptide tag (pTag) in the low nM range. The resulting drug strategy makes use of synthetic long peptide production of any tumor-associated antigen (TAA) of choice where the pTag itself ensures simple conjugate production to the protein, through affinity linkage, leading to a final rapid in-hospital mixing step. Data suggest that the novel candidate drug (STRIKE2001), now developed based on the ADAC concept[2], retains similar agonistic activity in its bispecific, IgG2 format and does not inhibit CD40L binding to the CD40 protein. Data further show impressive expansion of endogenous tumor-specific T cells (as measured by tetramer staining), along with effective anti-tumor responses in the TC1 model. In addition, by using the subcutaneous delivery strategy CD40 agonist exposure to liver and spleen is vastly reduced, limiting systemic immune toxicity/exhaustion risks[3]. [1] Padrón, L.J., et al. Sotigalimab and/or nivolumab with chemotherapy in first-line metastatic pancreatic cancer: clinical and immunologic analyses from the randomized phase 2 PRINCE trial. Nat Med 28, 1167-1177 (2022). https://doi.org/10.1038/s41591-022-01829-9 [2] Eltahir, M., et al. (2022), An Adaptable Antibody-Based Platform for Flexible Synthetic Peptide Delivery Built on Agonistic CD40 Antibodies. Adv. Therap., 5: 2200008. https://doi.org/10.1002/adtp.202200008 [3] Sandin, L., et al. Locally Delivered CD40 Agonist Antibody Accumulates in Secondary Lymphoid Organs and Eradicates Experimental Disseminated Bladder Cancer. Cancer Immunol Res 1 January 2014; 2 (1): 80-90. https://doi.org/10.1158/2326-6066.CIR-13-0067 Citation Format: Aman Mebrahtu, Ida Lauren, Rosanne Veerman, Alexandros Kostakis, Gözde Gucluler Akpinar, Oskar Andersson, Lindvi Gudmundsdotter, Tina Furebring, Helena Persson, Pierre Donnes, Johan Rockberg, Sara Mangsbo. Modular peptide cargo delivery by targeting CD40 enables ligandome driven, precision immunotherapy via the Adaptable Drug Affinity Conjugate (ADAC™) technology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2929.