Extensive Tissue Distribution Research Articles

Impact of Body Mass Index in the Cardioverter Efficacy of Amiodarone in Persistent Atrial Fibrillation

Background: Amiodarone is an anti-arrhythmic drug that has extensive tissue distribution and substantial storage in the fat tissue. Different studies have described some implications of body fat composition in its pharmacokinetics and pharmacodynamics. However, no clinical studies have described its implications for clinical efficacy. Methods: We studied 878 patients with persistent atrial fibrillation (AF) treated with a regimen of amiodarone and referred to electrical cardioversion (ECV), included prospectively in two Spanish registries. We analyzed the influence of body mass index (BMI), as well as overweight and obesity, in the efficacy of amiodarone for achieving pharmacologic cardioversion to sinus rhythm (SR) before ECV. Results: A total of 185 patients (21.1%) reverted to SR before ECV. Patients who reverted to SR had a lower BMI than those who did not revert (27.45 ± 4.36 kg/m2 vs. 29.11 ± 4.09 kg/m2; p < 0.001). We observed a progressively lower probability of reverting to SR in overweight and obese patients (normal weight 28.3%, overweight 21.3%, obesity 13.1%; p < 0.001). In the logistic regression, BMI (kg/m2) adjusted for other related variables remained as the main factor inversely related to reversion to SR (OR = 0.904 × kg/m2); CI 75% 0.864–0.946). Conclusions: We observed a negative relationship between an increased BMI and the efficacy of amiodarone for reversion to SR, suggesting a negative clinical impact of excess body fat in its efficacy.

Cannabidiol Bioavailability Is Nonmonotonic with a Long Terminal Elimination Half-Life: A Pharmacokinetic Modeling-Based Analysis.

Background: Oral and inhalation-based cannabidiol (CBD) administration has been clinically evaluated for various therapeutic indications, alongside widespread off-label use. However, the long-term exposure kinetics and varied bioavailability have not been fully characterized. Methods: Human CBD plasma concentration-time profiles from six studies evaluating the oral administration of Epidiolex® and three studies evaluating inhalation-based delivery were obtained. A four-compartment pharmacokinetic (PK) model with Weibull-based oral absorption kinetics was employed to describe the long-term PKs of CBD. Furthermore, a Cedergreen-Ritz-Streibig model was applied to evaluate nonmonotonic oral bioavailability. Results: CBD was extensively distributed into tissue compartments with varied kinetics resulting in a long plasma terminal elimination half-life of >134 h in humans. For once-a-day oral dosing, the plasma trough concentrations require >70 days to reach a steady state. The oral bioavailability of CBD for different doses administered in fasted state follows a nonmonotonic pattern with an inverted U-shaped profile. Oral administration of CBD under fed state or subjects with hepatic impairment yields higher oral bioavailability with varied exposure. In contrast, inhalation-based delivery of CBD, while delivering a similar systemic delivered dose compared with oral dosing due to high device losses, bypasses first-pass metabolism and can be efficient. Conclusion: CBD PKs vary across different doses due to nonmonotonic oral bioavailability, and inhalation-based delivery could minimize such variability in humans. The delayed attainment of steady state and prolonged terminal half-life, resulting from differential but extensive tissue distribution, needs to be considered when dosing CBD in the long term. These fundamental findings are critical for establishing dose-exposure relationship for further clinical evaluation of novel CBD-based therapies.

Anticarcinogenic Potency of EF24: An Overview of Its Pharmacokinetics, Efficacy, Mechanism of Action, and Nanoformulation for Drug Delivery.

EF24, a synthetic monocarbonyl analog of curcumin, shows significant potential as an anticancer agent with both chemopreventive and chemotherapeutic properties. It exhibits rapid absorption, extensive tissue distribution, and efficient metabolism, ensuring optimal bioavailability and sustained exposure of the target tissues. The ability of EF24 to penetrate biological barriers and accumulate at tumor sites makes it advantageous for effective cancer treatment. Studies have demonstrated EF24's remarkable efficacy against various cancers, including breast, lung, prostate, colon, and pancreatic cancer. The unique mechanism of action of EF24 involves modulation of the nuclear factor-kappa B (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways, disrupting cancer-promoting inflammation and oxidative stress. EF24 inhibits tumor growth by inducing cell cycle arrest and apoptosis, mainly through inhibiting the NF-κB pathway and by regulating key genes by modulating microRNA (miRNA) expression or the proteasomal pathway. In summary, EF24 is a promising anticancer compound with a unique mechanism of action that makes it effective against various cancers. Its ability to enhance the effects of conventional therapies, coupled with improvements in drug delivery systems, could make it a valuable asset in cancer treatment. However, addressing its solubility and stability challenges will be crucial for its successful clinical application.

Macrolide and Ketolide Antibiotics Inhibit the Cytotoxic Effect of Trastuzumab Emtansine in HER2-Positive Breast Cancer Cells: Implication of a Potential Drug-ADC Interaction in Cancer Chemotherapy.

Macrolides are widely used for the long-term treatment of infections and chronic inflammatory diseases. The pharmacokinetic features of macrolides include extensive tissue distribution because of favorable membrane permeability and accumulation within lysosomes. Trastuzumab emtansine (T-DM1), a HER2-targeting antibody-drug conjugate (ADC), is catabolized in the lysosomes, where Lys-SMCC-DM1, a potent cytotoxic agent, is processed by proteinase degradation and subsequently released from the lysosomes to the cytoplasm through the lysosomal membrane transporter SLC46A3, resulting in an antitumor effect. We recently demonstrated that erythromycin and clarithromycin inhibit SLC46A3 and attenuate the cytotoxicity of T-DM1; however, the effect of other macrolides and ketolides has not been determined. In this study, we evaluated the effect of macrolide and ketolide antibiotics on T-DM1 cytotoxicity in a human breast cancer cell line, KPL-4. Macrolides used in the clinic, such as roxithromycin, azithromycin, and josamycin, as well as solithromycin, a ketolide under clinical development, significantly attenuated T-DM1 cytotoxicity in addition to erythromycin and clarithromycin. Of these, azithromycin was the most potent inhibitor of T-DM1 efficacy. These antibiotics significantly inhibited the transport function of SLC46A3 in a concentration-dependent manner. Moreover, these compounds extensively accumulated in the lysosomes at the levels estimated to be 0.41-13.6 mM when cells were incubated with them at a 2 μM concentration. The immunofluorescence staining of trastuzumab revealed that azithromycin and solithromycin inhibit the degradation of T-DM1 in the lysosomes. These results suggest that the attenuation of T-DM1 cytotoxicity by macrolide and ketolide antibiotics involves their lysosomal accumulation and results in their greater lysosomal concentrations to inhibit the SLC46A3 function and T-DM1 degradation. This suggests a potential drug-ADC interaction during cancer chemotherapy.

Experimental co-infection of calves with SARS-CoV-2 Delta and Omicron variants of concern

ABSTRACT Since emerging in late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has repeatedly crossed the species barrier with natural infections reported in various domestic and wild animal species. The emergence and global spread of SARS-CoV-2 variants of concern (VOCs) has expanded the range of susceptible host species. Previous experimental infection studies in cattle using Wuhan-like SARS-CoV-2 isolates suggested that cattle were not likely amplifying hosts for SARS-CoV-2. However, SARS-CoV-2 sero- and RNA-positive cattle have since been identified in Europe, India, and Africa. Here, we investigated the susceptibility and transmission of the Delta and Omicron SARS-CoV-2 VOCs in cattle. Eight Holstein calves were co-infected orally and intranasally with a mixed inoculum of SARS-CoV-2 VOCs Delta and Omicron BA.2. Twenty-four hours post-challenge, two sentinel calves were introduced to evaluate virus transmission. The co-infection resulted in a high proportion of calves shedding SARS-CoV-2 RNA at 1- and 2-days post-challenge (DPC). Extensive tissue distribution of SARS-CoV-2 RNA was observed at 3 and 7 DPC and infectious virus was recovered from two calves at 3 DPC. Next-generation sequencing revealed that only the SARS-CoV-2 Delta variant was detected in clinical samples and tissues. Similar to previous experimental infection studies in cattle, we observed only limited seroconversion and no clear evidence of transmission to sentinel calves. Together, our findings suggest that cattle are more permissive to infection with SARS-CoV-2 Delta than Omicron BA.2 and Wuhan-like isolates but, in the absence of horizontal transmission, are not likely to be reservoir hosts for currently circulating SARS-CoV-2 variants.

Pharmacokinetics of a New Neuroprotector - Indenoquinoxalinone Derivative after Intravenous Administration in Rabbits and Rats.

The specific JNK inhibitor and NO donor 11H-indeno[1,2-b]quinoxalin-11-one oxime (IQ-1) demonstrated pronounced neuroprotective properties in an in vivo model of ischemic stroke in rats. The pharmacokinetic behavior of IQ-1 was studied in two animal species (rats, rabbits) after intravenous administration in a dose of 1 mg/kg. IQ-1 concentrations in venous blood plasma were measured by the liquid chromatography-tandem mass spectrometry method. The pharmacokinetics of IQ-1 was adequately described by the two-compartmental model. The calculated C0 for IQ-1 in rabbit and rat plasma were 2239.83±1229.55 and 1552.50±182.23 ng/ml, respectively. Two animal species are characterized by extensive tissue distribution of IQ-1 (Vss exceeded the total body water in rabbits and rats by 3.6 and 5.6 times, respectively) and high clearance values (88-94% of hepatic blood flow).

Development and DoE-ANN based optimization of novel swellable matrix-diffusible doxorubicin loaded zinc oxide nanoflowers using sonochemical-precipitation method

This research aimed to acquire doxorubicin loaded zinc oxide nanoflowers (DOX-ZnO-NFs) for intracellular drug cargo possessing a synergistic in-vitro anticancer activity with minimal toxicity. Zinc is the main inorganic metallic component of various enzyme systems and has the possibility of fabrication into the diverse nano-structural forms. An easy absorption and extensive tissue distribution of zinc have made it unique candidate for drug delivery system. Hence, the zinc oxide nanoflowers were prepared with sonochemical-precipitation. The developed system was characterized using the reported methods and was optimized employing design of experiment, coupled with artificial neural network approach. The optimized nanoflowers (DOX-ZnO-NFV) were anionic with particle size of 24 ± 0.05 nm, polydispersity index of <0.5, a zeta potential of −25.68 ± 0.16 mV, yield of 87.40% and encapsulation efficiency of 85.25%. DOX-ZNO-NFV depicted sustained DOX release, around 65.413% release in 30 h at pH 7.4 and assumed Weibull model with its derived parameters, a and b of 22.77 and 0.918, respectively. DOX-ZnO-NFV remained stable on storage for 3 months at 4° C/50% RH and 25° C/60% RH. DOX-ZnO-NFV displayed a zone of inhibition of 13.50 ± 1.25 mm and 25.50 ± 0.98 mm, respectively against gram-positive Staphylococcus aureus and gram-negative Escherichia coli strains, presenting the nanoflowers as self-preservative. DOX-ZnO-NFV exhibited higher in-vitro anticancer activity in Henrietta Lacks cell line, with least hemolysis compared to the free DOX and ZnO-NF. Thus, doxorubicin loaded zinc oxide nanoflowers envisioned to act as better chemotherapeutic cargos with the maximize anticancer activity and minimal toxicity.

Investigation of preclinical pharmacokinetics of N-demethylsinomenine, a potential novel analgesic candidate, using an UPLC-MS/MS quantification method.

N- Demethylsinomenine (NDSM), the in vivo demethylated metabolite of sinomenine, has exhibited antinociceptive efficacy against various pain models and may become a novel drug candidate for pain management. However, no reported analytical method for quantification of N- Demethylsinomenine in a biological matrix is currently available, and the pharmacokinetic properties of N- Demethylsinomenine are unknown. In the present study, an ultra-high performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method for quantification of N- Demethylsinomenine in rat plasma was developed and utilized to examine the preclinical pharmacokinetic profiles of N- Demethylsinomenine. The liquid-liquid extraction using ethyl acetate as the extractant was selected to treat rat plasma samples. The mixture of 25% aqueous phase (0.35% acetic acid-10mM ammonium acetate buffer) and 75% organic phase (acetonitrile) was chosen as the mobile phases flowing on a ZORBAX C18 column to perform the chromatographic separation. After a 6-min rapid elution, NDSM and its internal standard (IS), metronidazole, were separated successfully. The ion pairs of 316/239 and 172/128 were captured for detecting N- Demethylsinomenine and IS, respectively, using multiple reaction monitoring (MRM) under a positive electrospray ionization (ESI) mode in this mass spectrometry analysis. The standard curve met linear requirements within the concentration range from 3 to 1000ng/mL, and the lower limit of quantification (LLOQ) was 3ng/mL. The method was evaluated regarding precision, accuracy, recovery, matrix effect, and stability, and all the results met the criteria presented in the guidelines for validation of biological analysis method. Then the pharmacokinetic profiles of N- Demethylsinomenine in rat plasma were characterized using this validated UPLC-MS/MS method. N- Demethylsinomenine exhibited the feature of linear pharmacokinetics after intravenous (i.v.) or intragastric (i.g.) administration in rats. After i. v. bolus at three dosage levels (0.5, 1, and 2mg/kg), N- Demethylsinomenine showed the profiles of rapid elimination with mean half-life (T1/2Z) of 1.55-1.73h, and extensive tissue distribution with volume of distribution (VZ) of 5.62-8.07L/kg. After i. g. administration at three dosage levels (10, 20, and 40mg/kg), N- Demethylsinomenine showed the consistent peak time (Tmax) of 3h and the mean absolute bioavailability of N- Demethylsinomenine was 30.46%. These pharmacokinetics findings will aid in future drug development decisions of N- Demethylsinomenine as a potential candidate for pain analgesia.

Difloxacin Disposition and Residues in Broiler Chickens

Difloxacin disposition in broiler chickens was studied, with the objective of establishing pharmacokinetic parameters in plasma and tissues and estimating a withdrawal period. Forty-two adult chickens were divided into 14 groups of 3 individuals each, which received a 10 mg/kg single oral dose of difloxacin after a period of fasting between 12 hours before and 3 hours after administration. Each batch was sacrificed at pre-established times, and blood, muscle lung, liver, skin and kidney samples were obtained in a period up to 120 hours post application. Assay consisted in the extraction of the analyte, its separation and quantification by high performance liquid chromatography (HPLC). Mean plasma and tissue concentrations of difloxacin by time were analyzed with the PK Solution software. Oral application determines rapid absorption, moderate plasmatic permanence and extensive tissue distribution. The analysis of residual concentrations in tissues using WT 1.4 software calculated the withdrawal period, based on maximum residue limits (MRL) of 300, 1900, 400, 600 and 300 µg/kg, established for muscle, liver, skin, kidney and lung, respectively, a withdrawal period of 3 days is estimated for muscle, liver and skin and 5 days for kidney and lung.

Plasma Protein Binding Rate and Pharmacokinetics of Lekethromycin in Rats.

Lekethromycin (LKMS), a novel macrolide lactone, is still unclear regarding its absorption. Thus, we conducted this study to investigate the characteristics of LKMS in rats. We chose the ultrafiltration method to measure the plasma protein binding rate of LKMS. As a result, LKMS was characterized by quick absorption, delayed elimination, and extensive distribution in rats following intramuscular (im) and subcutaneous (sc) administration. Moreover, LKMS has a high protein binding rate (78–91%) in rats at a concentration range of 10–800 ng/mL. LKMS bioavailability was found to be approximately 84–139% and 52–77% after im and sc administration, respectively; however, LKMS was found to have extremely poor bioavailability after oral administration (po) in rats. The pharmacokinetic parameters cannot be considered linearly correlated with the administered dose. Additionally, LKMS and its corresponding metabolites were shown to be metabolically stable in the liver microsomes of rats, dogs, pigs, and humans. Notably, only one phase I metabolite was identified during in vitro study, suggesting most of drug was not converted. Collectively, LKMS had quick absorption but poor absorption after oral administration, extensive tissue distribution, metabolic stability, and slow elimination in rats.

Deferiprone: A Forty-Year-Old Multi-Targeting Drug with Possible Activity against COVID-19 and Diseases of Similar Symptomatology.

The need for preparing new strategies for the design of emergency drug therapies against COVID-19 and similar diseases in the future is rather urgent, considering the high rate of morbidity and especially mortality associated with COVID-19, which so far has exceeded 18 million lives. Such strategies could be conceived by targeting the causes and also the serious toxic side effects of the diseases, as well as associated biochemical and physiological pathways. Deferiprone (L1) is an EMA- and FDA-approved drug used worldwide for the treatment of iron overload and also other conditions where there are no effective treatments. The multi-potent effects and high safety record of L1 in iron loaded and non-iron loaded categories of patients suggests that L1 could be developed as a “magic bullet” drug against COVID-19 and diseases of similar symptomatology. The mode of action of L1 includes antiviral, antimicrobial, antioxidant, anti-hypoxic and anti-ferroptotic effects, iron buffering interactions with transferrin, iron mobilizing effects from ferritin, macrophages and other cells involved in the immune response and hyperinflammation, as well as many other therapeutic interventions. Similarly, several pharmacological and other characteristics of L1, including extensive tissue distribution and low cost of production, increase the prospect of worldwide availability, as well as many other therapeutic approach strategies involving drug combinations, adjuvant therapies and disease prevention.

Activity of Adagrasib (MRTX849) in Brain Metastases: Preclinical Models and Clinical Data from Patients with KRASG12C-Mutant Non-Small Cell Lung Cancer.

Patients with KRAS-mutant non-small cell lung cancer (NSCLC) with brain metastases (BM) have a poor prognosis. Adagrasib (MRTX849), a potent oral small-molecule KRASG12C inhibitor, irreversibly and selectively binds KRASG12C, locking it in its inactive state. Adagrasib has been optimized for favorable pharmacokinetic properties, including long half-life (∼24 hours), extensive tissue distribution, dose-dependent pharmacokinetics, and central nervous system penetration; however, BM-specific antitumor activity of KRASG12C inhibitors remains to be fully characterized. A retrospective database query identified patients with KRAS-mutant NSCLC to understand their propensity to develop BM. Preclinical studies assessed physiochemical and pharmacokinetic properties of adagrasib. Mice bearing intracranial KRASG12C-mutant NSCLC xenografts (LU99-Luc/H23-Luc/LU65-Luc) were treated with clinically relevant adagrasib doses, and levels of adagrasib in plasma, cerebrospinal fluid (CSF), and brain were determined along with antitumor activity. Preliminary clinical data were collected from 2 patients with NSCLC with untreated BM who had received adagrasib 600 mg twice daily in the phase Ib cohort of the KRYSTAL-1 trial; CSF was collected, adagrasib concentrations measured, and antitumor activity in BM evaluated. Patients with KRAS-mutant NSCLC demonstrated high propensity to develop BM (≥40%). Adagrasib penetrated into CSF and demonstrated tumor regression and extended survival in multiple preclinical BM models. In 2 patients with NSCLC and untreated BM, CSF concentrations of adagrasib measured above the target cellular IC50. Both patients demonstrated corresponding BM regression, supporting potential clinical activity of adagrasib in the brain. These data support further development of adagrasib in patients with KRASG12C-mutant NSCLC with untreated BM. See related commentary by Kommalapati and Mansfield, p. 3179.

UPLC-MS/MS method for the quantification of MCI-77, a novel sigma-1 receptor ligand, and its application to pharmacokinetic studies

Sigma-1 receptors are involved in pain modulation, particularly in cases of nerve injury and neuropathic pain. High-affinity ligands with improved pharmacokinetic profiles are needed to further investigate the properties of these receptors and their potential as a therapeutic target. The novel compound MCI-77 is one such selective sigma-1 receptor ligand, and the purpose of this study was to characterize its preclinical pharmacokinetic parameters. An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to quantify MCI-77 in mouse plasma and brain homogenate. The method was validated for sensitivity, selectivity, linearity, accuracy, precision, stability, and dilution integrity. The method has a linearity range of 2–200 ng/mL, a short run-time of 3.2 min, and requires a low sample volume of 25 µL. A simple protein precipitation procedure was used for compound extraction. Samples were run on an Acquity UPLC BEH C18 column (1.7 μm, 2.1 × 50 mm) following a gradient elution method using a mobile phase consisting of water containing 0.1% (v/v) formic acid and acetonitrile. The method was applied to the analysis of plasma and brain homogenate samples from preclinical pharmacokinetic studies in CD-1 mice. MCI-77 exhibited high systemic clearance (8.5 ± 0.3 L/h/kg) and extensive tissue distribution indicated by a high volume of distribution (20.1 ± 0.3 L/kg). The concentration levels were consistently higher in brain samples than in plasma (brain/plasma AUC ratio 2.9), indicating its ability to cross the blood–brain barrier.

KRYSTAL-1: Updated activity and safety of adagrasib (MRTX849) in patients (Pts) with unresectable or metastatic pancreatic cancer (PDAC) and other gastrointestinal (GI) tumors harboring a KRASG12C mutation.

519 Background: KRAS, the most frequently mutated oncogene in cancer, is a key mediator of the RAS/MAPK signaling cascade that promotes cellular growth and proliferation. KRAS mutations occur in approximately 90% of pancreatic cancer, and approximately 2% of these are KRASG12C mutations. Adagrasib, an investigational agent, is a KRASG12C inhibitor that irreversibly and selectively binds KRASG12C, locking it in its inactive state; adagrasib has been optimized for favorable pharmacokinetic (PK) properties, including long half-life (̃24 h), extensive tissue distribution, dose-dependent PK, as well as CNS penetration. Methods: KRYSTAL-1 (NCT03785249) is a multicohort Phase 1/2 study evaluating adagrasib as monotherapy or in combinations in pts with advanced solid tumors harboring a KRASG12C mutation. Here we report preliminary data from pts enrolled in a Phase 2 cohort evaluating single-agent adagrasib administered orally at 600 mg BID in previously treated pts with unresectable or metastatic solid tumors (excluding NSCLC and CRC), including pancreatic and other GI cancers. Study endpoints include clinical activity, safety, and PK. Results: The data cutoff was 10 September 2021. A total of 42 pts were enrolled in this cohort (median age 63.5 years, range 21–89; 52% female; 71% white; 29%/71% ECOG PS 0/1; median 2 prior lines of therapy, range 1–7; median follow-up 6.3 months), of whom 30 pts had KRASG12C-mutant GI tumors (12 PDAC, 8 biliary tract, 5 appendiceal, 2 gastro-esophageal junction, 2 small bowel, and 1 esophageal). In a preliminary analysis, 27 pts with GI tumors were evaluable for clinical activity; partial responses (PRs) were seen in 41% (11/27, including 3 unconfirmed PRs); the disease control rate (DCR) was 100% (27/27). Of the 12 pts with PDAC (median 3 prior lines of therapy; median follow-up 8.1 months), 10 were evaluable for clinical activity; PRs were seen in 50% (5/10, including 1 unconfirmed PR); the DCR was 100% (10/10). Median progression-free survival (PFS) was 6.6 months (95% CI 1.0–9.7), and treatment was ongoing in 50% of pts with PDAC. Among the 17 evaluable pts with other GI tumors, 6 achieved PR (35%; 2 unconfirmed) with a DCR of 100% (17/17); 11 pts were still receiving treatment. In the overall cohort, treatment-related adverse events of any grade occurred in 91% (38/42), the most frequent being nausea (48%), diarrhea (43%), vomiting (43%), and fatigue (29%); grade 3/4 events occurred in 21% of pts, with no grade 5 events. Conclusions: Adagrasib monotherapy is well tolerated and demonstrates encouraging clinical activity in pretreated pts with PDAC and other GI tumors harboring a KRASG12C mutation. Further exploration of adagrasib is ongoing in this pt population (NCT03785249). Clinical trial information: NCT03785249.

Preclinical Pharmacokinetics and Safety of Intravenous RTD-1.

ABSTRACTSevere illness caused by coronavirus disease 2019 (COVID-19) is characterized by an overexuberant inflammatory response resulting in acute respiratory distress syndrome (ARDS) and progressive respiratory failure (A. Gupta, M. V. Madhavan, K. Sehgal, N. Nair, et al., Nat Med 26:1017–1032, 2020, https://doi.org/10.1038/s41591-020-0968-3). Rhesus theta (θ) defensin-1 (RTD-1) is a macrocyclic host defense peptide exhibiting antimicrobial and immunomodulatory activities. RTD-1 treatment significantly improved survival in murine models of a severe acute respiratory syndrome (SARS-CoV-1) and endotoxin-induced acute lung injury (ALI) (C. L. Wohlford-Lenane, D. K. Meyerholz, S. Perlman, H. Zhou, et al., J Virol 83:11385–11390, 2009, https://doi.org/10.1128/JVI.01363-09; J. G. Jayne, T. J. Bensman, J. B. Schaal, A. Y. J. Park, et al., Am J Respir Cell Mol Biol 58:310–319, 2018, https://doi.org/10.1165/rcmb.2016-0428OC). This investigation aimed to characterize the preclinical pharmacokinetics (PK) and safety of intravenous (i.v.) RTD-1. Based on the lack of adverse findings, the no observed adverse effect level (NOAEL) was established at 10 mg/kg/day in rats and 15 mg/kg/day in monkeys. Analysis of single ascending dose studies in both species revealed greater-than-dose-proportional increases in the area under the curve extrapolated to infinity (AUC0-∞) (e.g., 8-fold increase from 5 mg/kg to 20 mg/kg in rats) suggestive of nonlinear PK. The volume of distribution at steady state (Vss) ranged between 550 and 1,461 mL/kg, indicating extensive tissue distribution, which was validated in a biodistribution study of [14C]RTD-1 in rats. Based on interspecies allometric scaling, the predicted human clearance and Vss are 6.48 L/h and 28.0 L, respectively, for an adult (70 kg). To achieve plasma exposures associated with therapeutic efficacy established in a murine model of ALI, the estimated human equivalent dose (HED) is between 0.36 and 0.83 mg/kg/day. The excellent safety profile demonstrated in these studies and the efficacy observed in the murine models support the clinical investigation of RTD-1 for treatment of COVID-19 or other pulmonary inflammatory diseases.

Phylogeny of the HO family in cyprinus carpio and the response of the HO-1 gene to adding Bacillus coagulans in feed under Cd2+ stress.

The heavy metal cadmium (Cd2+) is an environmental pollutant that poses serious health hazards. Due to the increasing contamination of aquatic systems with Cd2+, the increased accumulation of Cd2+ in fish has become a food safety and public health concern. Heme oxygenase (HO) is an important antioxidant enzyme that plays a key role in defending the body against oxidative damage, but little research has been done in common carp. In this study, 6 HO genes were identified in the common carp genome database. Comparative genomics analysis showed considerable expansion of the HO genes and verified the four-round whole genome duplication (WGD) event in common carp. Phylogenetic analysis revealed that all HO genes of common carp were clustered into orthologous groups, indicating high conservation during evolution. In addition, the tissue distribution results showed that most HO genes had extensive tissue distribution and showed tissue-specific expression patterns. Exposure to 0.5mg/L Cd2+ significantly reduced the expression of TGF-β and IL-10 in common carp, which may indicate that Cd2+ exposure can destroy the physical barrier function of the intestine, inhibit intestinal immune defense and induce intestinal inflammation. To find a suitable concentration of Bacillus coagulans that could activate HO-1 genes and the immunity of the organism, we investigated the changes in HO-1 gene expression levels in the intestinal tract of common carp under Cd2+ stress at 30days and 60days by adding different concentrations of B. coagulans to the feed. Compared with the Cd2+ stress group without supplementation, the expression levels of the HO-1 gene in the gut of three different concentrations of B. coagulans were almost increased. And B. coagulans with L2 concentrations had better activation effect on the HO-1 gene. Similarly, compared to the Cd2+ stressed group, adding B. coagulans to the diet can almost cause the early upregulation of IL-10 and TGF-β genes. Therefore, the addition of appropriate concentrations of B. coagulans may be a good way to activate HO-1, IL-10, and TGF-β genes, reduce oxidative damage, and encourage the immune.

P-71 KRYSTAL-10: A randomized phase 3 study of adagrasib (MRTX849) in combination with cetuximab vs chemotherapy in patients with previously treated advanced colorectal cancer with KRASG12C mutation

KRAS G12C mutation occurs in 3-4% of colorectal cancer (CRC) and is associated with poor prognosis. KRAS is a key mediator of the RAS/MAPK signaling cascade and promotes cellular growth and proliferation. Cetuximab, an EGFR-inhibiting monoclonal antibody, is indicated as monotherapy or in combination with chemotherapy for the treatment of KRAS wild-type metastatic CRC. However, in patients (pts) with KRAS G12C mutation, EGFR antibodies lack clinical activity, and no targeted therapy has been approved in this population, presenting a large unmet need for new treatments. Adagrasib, an investigational agent, is a potent, covalent inhibitor of KRAS G12C that irreversibly and selectively binds to KRAS G12C and locks it in its inactive state. Adagrasib was optimized for favorable PK properties, including oral bioavailability, long half-life (∼24 h), and extensive tissue distribution. Initial results from the Phase 1b KRYSTAL-1 study demonstrated encouraging antitumor activity and tolerability of adagrasib monotherapy (600 mg BID). In pretreated pts with CRC harboring KRASG12C mutation who had received a median of 4 prior lines of therapy, 17% (3/18) had confirmed objective responses and the disease control rate (DCR) was 94% as of the August 2020 data cutoff. Despite this observed activity of KRAS G12C inhibition, reactivation of RAS/MAPK pathway signaling may occur through adaptive feedback mediated by EGFR, which is expressed in a variety of human tumors including CRC. These observations indicate that combined treatment of adagrasib with cetuximab may enhance inhibition of KRAS-dependent signaling to overcome adaptive feedback and improve clinical outcomes. Preclinical data in KRAS G12C human xenograft CRC mouse models suggest synergistic activity of adagrasib and cetuximab. These data, along with initial feasibility and efficacy signals seen in KRYSTAL-1, support further evaluation of the combination. Open-label, randomized Phase 3 study. KRYSTAL-10 (NCT04793958) is a global, open-label, randomized Phase 3 study evaluating the efficacy and safety of adagrasib (600 mg BID) in combination with cetuximab (500 mg/m2 Q2W) vs chemotherapy in pts with CRC harboring a KRAS G12C mutation who have progressed on or after treatment with a standard first-line fluoropyrimidine-based chemotherapy regimen containing either oxaliplatin or irinotecan. Pts randomized to the chemotherapy control arm will receive FOLFIRI or mFOLFOX6 depending on their first-line treatment regimen; a VEGF/VEGFR inhibitor may be used in combination with chemotherapy at the investigator’s discretion. Dual primary endpoints are progression-free survival (PFS) and overall survival (OS). Secondary endpoints include safety, objective response rate (ORR) per RECIST 1.1, duration of response (DOR), plasma PK parameters of adagrasib, and patient-reported outcomes (PROs). The study will also explore correlations between tumor biomarkers, gene alterations (at baseline and upon treatment resistance), and efficacy. Approximately 420 pts will be randomized 1:1 to receive adagrasib in combination with cetuximab or chemotherapy. Randomization will be stratified by region (United States/Canada vs all other countries) and time to disease progression after beginning first-line treatment (This study will be enrolling at sites in North America, South America, Europe, Asia, and Australia. NCT04793958. Writing and editorial assistance were provided by Rohan Gidvani of Axiom Healthcare Strategies, funded by Mirati Therapeutics, Inc. Mirati Therapeutics, Inc.

KRYSTAL-12: A randomized phase 3 study of adagrasib (MRTX849) versus docetaxel in patients (pts) with previously treated non-small-cell lung cancer (NSCLC) with KRASG12C mutation.

TPS9129 Background: Despite significant advances in chemotherapy and immunotherapy for advanced NSCLC, the majority of pts ultimately develop progressive disease associated with poor outcomes. KRAS is a key mediator of the RAS/MAPK signaling cascade that promotes cell growth and proliferation. KRASG12C mutations occur in 14% of NSCLC (adenocarcinoma), and mutations in KRAS are associated with a poor prognosis. Although KRAS has historically been undruggable, recent research into the development of agents that specifically bind mutant KRAS has led to the development of direct inhibitors of KRASG12C. Adagrasib, an investigational agent, is a potent, covalent inhibitor of KRASG12C that irreversibly and selectively binds to and locks KRASG12C in its inactive state. Adagrasib was optimized for favorable pharmacokinetic (PK) properties, including oral bioavailability, long half-life (̃24 h), and extensive tissue distribution. Initial results have demonstrated encouraging antitumor activity and tolerability of adagrasib monotherapy in pts with NSCLC harboring a KRASG12C mutation. Methods: KRYSTAL-12 is a multicenter, randomized Phase 3 study evaluating the efficacy of adagrasib (600 mg BID) vs docetaxel in pts with advanced NSCLC harboring a KRASG12C mutation who have progressed during or after treatment with a platinum-based regimen and an immune checkpoint inhibitor. The study is designed to demonstrate improvement in the dual primary endpoints of progression-free survival (PFS) and overall survival (OS). Secondary endpoints include safety, objective response rate (ORR) per RECIST 1.1, duration of response (DOR), plasma PK parameters of adagrasib, and patient-reported outcomes (PROs). The study will also explore correlations between gene alterations (at baseline and upon development of treatment resistance) and efficacy. Approximately 450 patients will be randomized in a 2:1 ratio to receive adagrasib or docetaxel and will be stratified by region (United States/Canada vs other countries) and sequential vs concurrent administration of prior platinum-based chemotherapy and anti–PD-1/PD-L1 antibody. The planned sample size is sufficiently powered for the hypothesized treatment effect of the endpoints. Pts will receive study treatment until disease progression, unacceptable adverse events, investigator decision to terminate treatment, or patient withdrawal. This study is currently enrolling and will be open at sites in the United States, Europe, and Asia. Clinical trial information: NCT04685135.

KRYSTAL-2: A phase I/II trial of adagrasib (MRTX849) in combination with TNO155 in patients with advanced solid tumors with KRAS G12C mutation.

TPS146 Background: KRAS is the most frequently mutated oncogene in cancer and a key mediator of the RAS/MAPK signaling cascade that promotes cellular growth and proliferation. KRAS G12C tumor mutations occur in approximately 14% of patients with lung adenocarcinoma and 3-4% of colorectal adenocarinoma. SHP2 is a phosphatase that acts as a key mediator of signaling from receptor tyrosine kinases (RTKs) to downstream RAS/MAPK pathways. Adagrasib (MRTX849) is a specific small-molecule investigational inhibitor of KRAS G12C that covalently binds to and locks mutant KRAS in its GDP-bound inactive form. Adagrasib has been optimized for a long half-life and extensive tissue distribution to enable inhibition throughout the entire dosing interval. Preliminary results from a Phase 1/2 study of adagrasib demonstrated promising antitumor activity and tolerability across multiple KRAS G12C tumor types. TNO155 is a selective inhibitor of SHP2 with demonstrated inhibition of RTK signaling and significant antitumor activity in preclinical models. Preclinical studies have shown that resistance to KRAS G12C inhibition may be mediated by SHP2-dependent feedback loops. Because KRAS G12C retains some level of cycling between GTP- and GDP-bound states, KRAS G12C that is not bound by inhibitor can activate downstream signaling. Active SHP2 functions to increase the active state of RAS proteins (including mutant KRAS) and also increases ERK pathway activation. Therefore, the addition of TNO155 to adagrasib may augment antitumor activity and overcome resistance by inhibiting cycling to GTP-bound KRAS and/or through inhibition of feedback activation and more comprehensively inhibiting downstream ERK signaling. In KRAS G12C human tumor models, adagrasib combined with a SHP2 inhibitor demonstrated greater activity compared to each agent alone. These data provide support for clinical evaluation of this combination in KRAS G12C tumors. Methods: KRYSTAL-2 is a multicenter Phase 1/2 study evaluating adagrasib and TNO155 in patients with advanced solid tumors harboring a KRAS G12C mutation. Overall objectives of the trial include evaluating safety, tolerability, and PK. The Phase 1 portion will evaluate adagrasib and TNO155 utilizing a modified Toxicity Probability Interval dose escalation design to identify maximum tolerated dose and recommended Phase 2 dose. The Phase 2 portion utilizes a Simon's optimal two-stage design to evaluate the clinical activity of adagrasib with TNO155 in 2 cohorts of up to 108 patients—CRC (54 patients) and NSCLC (54 patients). Efficacy endpoints include Objective Response Rate (RECIST 1.1), Duration of Response (DOR), Progression-free Survival (PFS), and Overall Survival (OS). The study is currently enrolling and patients will receive study treatment until disease progression, unacceptable adverse events, patient withdrawal, or death. Clinical trial information: NCT04330664.

637. Outcomes by Body Mass Index (BMI) in the STRIVE Phase 2 Trial of Once-Weekly Rezafungin for Treatment of Candidemia and Invasive Candidiasis Compared with Caspofungin

BackgroundThere is increasing evidence of antifungal underdosing in the treatment of invasive disease, particularly in special populations such as the obese. Body size is often an important variable affecting drug exposure, and pharmacokinetic (PK) models of antifungal dosing have suggested size-based dose adjustments to achieve target drug exposure.Rezafungin (RZF) is a novel echinocandin in Phase 3 development for treatment of candidemia and invasive candidiasis (IC) and for prevention of invasive fungal disease caused by Candida, Aspergillus, and Pneumocystis in blood and marrow transplant recipients. Distinctive PK properties of RZF (e.g., long half-life, extensive tissue distribution, and front-loaded drug exposure) lend themselves to RZF once-weekly (QWk) dosing and antifungal efficacy. In this sub-analysis of the Phase 2 STRIVE trial of RZF in the treatment of candidemia and/or IC, outcomes based on patient BMI were evaluated.MethodsThe STRIVE trial (NCT02734862) compared the safety and efficacy of RZF QWk compared with once-daily caspofungin (Fig. 1). For this subanalysis, data were stratified by BMI categories of < 30 kg/m2 and ≥ 30 kg/m2. Efficacy (overall response [resolution of clinical signs of infection + mycological eradication], mycological response, and investigator assessment of clinical response) and safety (treatment-emergent adverse events [TEAEs]) endpoints by treatment group were evaluated, as well as PK data (area under the curve [AUC]) from RZF-treated patients.Figure 1. ResultsMean BMI values were similar across treatment arms (26.9 kg/m2 in RZF Group 1 and 26.8 kg/m2 in RZF Group 2 and CAS arms). Efficacy outcomes at Day 14 were similar between BMI categories (Table 1). Rates of TEAEs were generally similar between BMI categories as well (Table 2), with no concerning safety trends. Following one dose of RZF 400 mg (Week 1), the ranges of AUCs by BMI category overlapped and there was a minor mean difference of ~20% (lower for those with BMI ≥ 30 kg/m2) (Fig. 2).Table 1 Table 2 Figure 2. ConclusionThe safety, efficacy, and PK of RZF in the Phase 2 STRIVE trial was consistent across BMI categories. These results suggest that dose adjustments in obese patients are not necessary. These findings contribute to the evaluation of RZF in a range of patient populations and its ongoing development.Disclosures Shawn Flanagan, PhD, Cidara Therapeutics, Inc. (Employee, Shareholder) Peter Pappas, MD, SCYNEXIS, Inc. (Consultant, Advisor or Review Panel member, Research Grant or Support) Taylor Sandison, MD, MPH, Cidara Therapeutics, Inc. (Employee, Shareholder) Patrick M. Honore, MD, PhD, FCCM, Cidara Therapeutics, Inc. (Scientific Research Study Investigator)