Safety Pharmacology Studies Research Articles

Toxicology profile of a novel GLP-1 receptor biased agonist-SAL0112 in nonhuman primates

Oral small-molecule GLP-1 receptor biased agonists exhibit promising treatment efficacy of type 2 diabetes and obesity. SAL0112 is a novel compound that has demonstrated remarkable efficacy in preclinical animal models. Herein, both in vitro and in vivo preclinical toxicity investigations were conducted to explore the safety profile of SAL0112. The HTRF assay and TR-FRET assay were utilized for cAMP detection. Patch clamp assay was employed for hERG potassium ion channel determination. Cynomolgus monkeys were used in a cardiovascular safety pharmacology study and a 13-week repeated dose toxicity study. The telemetry system was employed to detect cardiovascular indicators such as ECG, HR, and BP. During the repeated dose toxicity study, body weight, food intake, hematology, coagulation function test, serum biochemistry tests, and urine analysis were measured. Macroscopic and microscopic observations were conducted at the end of the study. TK studies were conducted on Day 1 and Day 91. SAL0112 exhibited a high degree of potency in activating the monkey GLP-1 receptor whereas had no effect on the rodent GLP-1 receptor. In contrast to Danuglipron, which demonstrated high potency on hERG with an IC50 value of 6.9 μM, the IC50 of SAL0112 on hERG was greater than 100 μM. Compared to the Vehicle Control group, no significant changes in cardiovascular indicators were observed in the cardiovascular safety pharmacology study after a single dose of SAL0112 up to 250 mg/kg (P > 0.05). A repeated dose toxicity study revealed moderate anorexigenic effects and a reduction in body weight, effects that were found to be reversible and not associated with any pathological changes. The NOAEL of SAL0112 is 150 mg/kg, providing an approximate safety margin of threefold. SAL0112 demonstrated a favorable safety profile in cynomolgus monkeys, with a substantial therapeutic window that supports the progression of this compound into clinical studies.

Respiratory Responses to a Single Oral Dose of Caffeine in Male Sprague-Dawley Rats.

Caffeine is a key component of beverages such as coffee and tea and has effects on the cardiovascular and respiratory systems, prompting a variety of physiological changes. In our previous study, intravenously administered caffeine at high concentrations significantly influenced respiratory rates. However, comparative research on the potential adverse effects of caffeine consumption on the respiratory system is limited. To address this issue, in this study, we focused on evaluating the effects of orally administered caffeine (0, 2, 6, and 20 mg/kg) on the respiratory system of 6-week-old male Sprague-Dawley rats. We measured the respiratory rate, tidal volume, and minute volume following the guidelines set forth by the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use, specifically adhering to Harmonized Tripartite Guideline S7A for Safety Pharmacology Studies for Human Pharmaceuticals. Caffeine administration led to a notable increase in both the respiratory rate and the tidal volume. Conversely, a marked reduction in minute volume was recorded between 0.5 and 2 h following caffeine administration in doses exceeding 6 mg/kg.

Reevaluating safety pharmacology respiratory studies within the ICH S7A core battery: A multi-company evaluation of preclinical utility and clinical translation

Optimization of ICH safety guideline studies for inclusion into regulatory submissions is critical for resource conservation, animal use reduction, and efficient drug development. The ICH S7A guidance for Safety Pharmacology (SP) studies adopted in 2001 identified the core battery of studies to evaluate the acute safety of putative pharmaceutical molecules prior to First in Human (FIH) trials. To assess the utility of respiratory studies in predicting clinical AE's, seven pharmaceutical companies pooled preclinical and clinical respiratory findings. A large database of novel molecules included all relevant data from standard S7A respiratory (n = 459) and FIH studies (n = 309). The data were analyzed with respect to the progression of these molecules, clinical adverse event reporting of these same molecules, and achieved exposures. These S7A respiratory assay findings had no impact on compound progression, and only 12 of 309 drug candidates were ‘positive’ preclinically and reported a respiratory-related AE in clinical trials (i.e. cough, dyspnea, etc.), an overall incidence rate of 3.9%. Contingency tables/statistics support a lack of concordance of these preclinical assays. Overall, our extensive analysis clearly indicated that the preclinical respiratory assay fails to provide any prognostic value for detecting clinically relevant respiratory adverse events.

Potential of 6′‑hydroxy justicidin B from Justicia procumbens as a therapeutic agent against coronavirus disease 2019

BackgroundSince the onset of the coronavirus disease 2019 (COVID-19) pandemic, remarkable advances have been made in vaccine development to reduce mortality. However, therapeutic interventions for COVID-19 are comparatively limited despite these intensive efforts. Furthermore, the rapid mutation capability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a characteristic of its RNA structure, has led to the emergence of multiple variants, necessitating a shift from a predominantly vaccine-centric approach to one that encompasses therapeutic strategies. 6′-Hydroxy justicidin B (6′-HJB), an arylnaphthalene lignan isolated from Justicia procumbens, a traditional Chinese medicine, is known for its antiviral properties. Hypothesis/PurposeThe aim of the present study was to assess the effectiveness and safety of 6′-HJB against SARS-CoV-2 in order to determine its potential as a therapeutic agent against COVID-19. MethodsThe efficacy of 6′-HJB was evaluated both in vitro using Vero and Calu-3 cell lines and in vivo using ferrets. The safety assessment included toxicokinetics, safety pharmacology, and Good Laboratory Practice (GLP)-compliant toxicity evaluations following single- and repeated-dose toxicity studies in dogs. ResultsThe anti-SARS-CoV-2 efficacy of 6′-HJB was evaluated through dose-response curve (DRC) analysis using immunofluorescence; 6′-HJB demonstrated superior inhibition of SARS-CoV-2 growth and lower cytotoxicity than remdesivir. In SARS-CoV-2-infected ferret, 6′-HJB showed efficacy comparable to that of the positive control, Truvada. Further GLP toxicity studies corroborated the safety profile of 6′-HJB. Single-dose and 4-week repeated oral toxicity studies in Beagle dogs demonstrated minimal harmful effects at the highest dosages. The lethal dose of 6′-HJB exceeded 2,000 mg kg-1 in Beagle dogs. Toxicokinetic and GLP safety pharmacology studies demonstrated no adverse effects of 6′-HJB on metabolic processes, respiratory or central nervous systems, or cardiac functions. ConclusionThis research highlights both the antiviral efficacy and safety profile of 6′-HJB, underscoring its potential as a novel COVID-19 treatment option. The potential of 6′-HJB was demonstrated using modern scientific methodologies and standards.

Safety pharmacology of human endogenous retrovirus-enveloped baculoviral DNA vaccines against SARS-CoV-2 in Sprague-Dawley rats and beagle dogs

The coronavirus disease 2019 (COVID-19) emerged as a major global health crisis, posing significant health, economic, and social challenges. Vaccine development has been a crucial response to the severe-acute-respiratory-syndrome-related coronavirus-2 pandemic owing to the critical role of immunization in controlling infectious diseases, leading to the expedited development of several effective vaccines. Although mRNA platform-based COVID-19 vaccines authorized under emergency-use authorization have been administered globally, concerns regarding the vaccines have increased owing to the occurrence of various side effects. The present study aimed to evaluate the safety of a non-replicating recombinant baculovirus expressing the human endogenous retrovirus envelope gene (AcHERV) vaccine encoding SARS-CoV-2 antigens. Owing to the limited number of existing safety pharmacology studies on AcHERV as a viral vector vaccine, we conducted neurobehavior (Modified Irwin’s Test), body temperature, and respiratory function studies in rats and cardiovascular system studies in male beagle dogs, which were administered the AcHERV-COVID-19 vaccine using telemetry. The safety assessment revealed no significant toxicological alterations. However, in rats, both sexes administered with the AcHERV-COVID-19 vaccine exhibited a temporary increase in body temperature, which normalized or showed signs of recovery. In conclusion, AcHERV-COVID-19 demonstrates a sufficient safety profile that supports its potential evaluation in future clinical trials.

Innovative approaches to cardiovascular safety pharmacology assessment

This editorial prefaces the annual themed issue on safety pharmacology (SP) methods which has been published since 2004 in the Journal of Pharmacological and Toxicological Methods (JPTM). Here we highlight content derived from the 2023 Safety Pharmacology Society (SPS) meeting held in Brussels, Belgium. The meeting generated 138 abstracts, reproduced in the current volume of JPTM. As in prior years, the manuscripts reflect various areas of innovation in SP including in silico modeling of stroke volume, cardiac output and systemic vascular resistance, computational approaches that compare drug-induced proarrhythmic sensitivity of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), an evaluation of the utility of the corrected J-Tpeak and Tpeak-to-Tend parameters from the ECG as potential proarrhythmia biomarkers, and the applicability of nonclinical concentration-QTc (C-QTc) modeling of data derived from the conduct of the in vivo QTc study as a component of the core battery of safety pharmacology studies.

A simple accurate method for concentration-QTc analysis in preclinical animal models

IntroductionIn preclinical cardiovascular safety pharmacology studies, statistical analysis of the rate corrected QT interval (QTc) is the focus for predicting QTc interval changes in the clinic. Modeling of a concentration/QTc relationship, common clinically, is limited due to minimal pharmacokinetic (PK) data in nonclinical testing. It is possible, however, to relate the average drug plasma concentration from sparse PK samples over specific times to the mean corrected QTc. We hypothesize that averaging drug plasma concentration and the QTc-rate relationship over time provides a simple, accurate concentration-QTc relationship bridging statistical and concentration/QTc modeling. MethodsCardiovascular telemetry studies were conducted in non-human primates (NHP; n = 48) and canines (n = 8). Pharmacokinetic samples were collected on separate study days in both species. Average plasma concentrations for specific intervals (CAverage0-X) were calculated for moxifloxacin in canines and NHP using times corresponding to super-intervals for the QTc data statistical analysis. The QTc effect was calculated for each super-interval using a linear regression correction incorporating QT and HR data from the whole super-interval. The concentration QTc effects were then modeled. ResultsIn NHP, a 10.9 ± 0.06 ms (mean ± 95% CI) change in QTc was detected at approximately 1.5× the moxifloxacin plasma concentration that causes a 10 ms QTc change in humans, based on a 0-24 h super-interval. When simulating a drug without QT effects, mock, no effect on QTc was detected at up to 3× the clinical concentration. Similarly, in canines, a 16.6 ± 0.1 ms change was detected at 1.7× critical clinical moxifloxacin concentration, and a 0.04 ± 0.1 ms change was seen for mock. ConclusionsWhile simultaneous PK and QTc data points are preferred, practical constraints and the need for QTc averaging did not prevent concentration-QTc analyses. Utilizing a 0-24 h super-interval method illustrates a simple and effective method to address cardiovascular questions when preclinical drug exposures exceed clinical concentrations.

Supporting an integrated QTc risk assessment using the hERG margin distributions for three positive control agents derived from multiple laboratories and on multiple occasions.

BackgroundDetermination of a drug's potency in blocking the hERG channel is an established safety pharmacology study. Best practice guidelines have been published for reliable assessment of hERG potency. In addition, a set of plasma concentration and plasma protein binding fraction data were provided as denominators for margin calculations.The aims of the current analysis were five-fold: provide data allowing creation of consistent denominators for the hERG margin distributions of the key reference agents, explore the variation in hERG margins within and across laboratories, provide a hERG margin to 10 ms QTc prolongation based on several newer studies, provide information to use these analyses for reference purposes, and provide recommended hERG margin ‘cut-off’ values. MethodsThe analyses used 12 hERG IC50 ‘best practice’ data sets (for the 3 reference agents). A group of 5 data sets came from a single laboratory. The other 7 data sets were collected by 6 different laboratories. ResultsThe denominator exposure distributions were consistent with the ICH E14/S7B Training Materials. The inter-occasion and inter-laboratory variability in hERG IC50 values were comparable. Inter-drug differences were most important in determining the pooled margin variability. The combined data provided a robust hERG margin reference based on best practice guidelines and consistent exposure denominators. The sensitivity of hERG margin thresholds were consistent with the sensitivity described over the course of the last two decades. ConclusionThe current data provide further insight into the sensitivity of the 30-fold hERG margin ‘cut-off’ used for two decades. Using similar hERG assessments and these analyses, a future researcher can use a hERG margin threshold to support a negative QTc integrated risk assessment.

The FIPO23 trial: First-in-human phase I/II study of XON7 in advanced solids tumors.

TPS2673 Background: XON7 is a first-in-class glyco-humanized polyclonal antibody (GH-pAb) targeting selectively multiple tumor-associated antigens. XON7 induces tumor cell apoptosis and promotes the elimination of tumor cells by immune effector cells through CDC (Complement Dependent Cytotoxicity) and ADCP (Antibody-Dependent Cell Phagocytosis). XON7 demonstrated anti-tumor efficacy in mice xenograft models with human solid tumors such as colon, prostate, lung and triple negative breast cancers. Safety pharmacology and toxicology studies in non-human primates demonstrated an acceptable safety profile for XON7. Taken together, these preclinical data support the initiation of human trials in patients with advanced solid tumors. Methods: First-in-patient, multicenter, open-label, two phases (dose-escalation (ESC) followed by dose expansion (EXP)) study of XON7 single agent, in patients with relapsed refractory, locally advanced or metastatic solid tumors without standard available treatments ( NCT06154291). Key eligibility criteria include disease progression after ≤ 4 lines of therapy; age > 18 years; ECOG performance status ≤2; adequate organ functions; no known CNS involvement. All advanced or metastatic tumor types except glioblastoma, can be included during ESC. Primary endpoints: safety, tolerability and determination of MTD/RP2D. Secondary endpoints: pharmacokinetics (PK), pharmacodynamics, immunogenicity and preliminary anti-tumor activity (RECIST 1.1). AEs graded according to CTCAE 5.0. In the ESC part, XON7 is administered as 60-min intravenous infusion every 2 weeks according to an escalating schedule of doses from 1.5 to 20 mg/kg for up to 12, 28-day cycles. Dose escalation/de-escalation is based on the Bayesian Optimal Interval (BOIN) design, up to 45 pts are planned. At the recommended dose, up to 7 EXP cohorts (30 pts each) defined according to the primary tumor site are planned. Bayesian sequential monitoring will be used. Patient recruitment is planned or ongoing at 25 sites worldwide. Results: As of Feb 3rd, 2024, 3 pts are enrolled in the first dose cohort and have received XON7 at dose 1,5 mg/kg Q2W for the first 28-days cycle. Conclusions Accrual is ongoing in this first-in-human trial of XON7. Clinical trial information: NCT06154291 .

In silico modelling of stroke volume, cardiac output and systemic vascular resistance in cardiovascular safety pharmacology studies by telemetry

The principle of proportionality of the systolic area of the central aortic pressure to stroke volume (SV) has been long known. The aim of the present work was to evaluate an in silico solution derived from this principle for modelling SV (iSV model) in cardiovascular safety pharmacology studies by telemetry. Blood pressure was measured in the abdominal aorta in accordance with standard practice. Central aortic pressure was modelled from the abdominal aortic pressure waveform using the N-point moving average (NPMA) method for beat-to-beat estimation of SV. First, the iSV was compared to the SV measured by ultrasonic flowmetry in the ascending aorta (uSV) after various pharmacological challenges in beagle dogs anaesthetised with etomidate/fentanyl. The iSV showed minimal bias (0.2 mL i.e. 2%) and excellent agreement with uSV. Then, previous telemetry studies including reference vasoactive and inotropic compounds were retrospectively reanalysed to model drug effects on stroke volume (iSV), cardiac output (iCO) and systemic vascular resistance (iSVR). Among them, the examples of nicardipine and isoprenaline highlight risks of erroneous or biased estimation of drug effects from the abdominal aortic pressure due to pulse pressure amplification. Furthermore, the examples of verapamil, quinidine and moxifloxacin show that iSV, iCO and iSVR are earlier biomarkers than blood pressure itself for predicting drug effect on blood pressure. This in silico modelling approach included in vivo telemetry safety pharmacology studies can be considered as a New Approach Methodology (NAM) that provides valuable additional information and contribute to improving non-clinical translational research to the clinic.

A comparison of the performance of contemporary, historical, and cross-lab controls in QTc assessment in conscious nonhuman primates

Cardiovascular safety pharmacology and toxicology studies include vehicle control animals in most studies. Electrocardiogram data on common vehicles is accumulated relatively quickly. In the interests of the 3Rs principles it may be useful to use this historical information to reduce the use of animals or to refine the sensitivity of studies.We used implanted telemetry data from a large nonhuman primate (NHP) cardiovascular study (n = 48) evaluating the effect of moxifloxacin. We extracted 24 animals to conduct a n = 3/sex/group analysis. The remaining 24 animals were used to generate 1000 unique combinations of 3 male and 3 female NHP to act as control groups for the three treated groups in the n = 3/sex/group analysis. The distribution of treatment effects, median minimum detectable difference (MDD) values were gathered from the 1000 studies. These represent contemporary controls.Data were available from 42 NHP from 3 other studies in the same laboratory using the same technology. These were used to generate 1000 unique combinations of 6, 12, 18, 24 and 36 NHP to act as historical control animals for the 18 animals in the treated groups of the moxifloxacin study. Data from an additional laboratory were also available for 20 NHP.The QT, RR and QT-RR data from the three sources were comparable. However, differences in the time course of QTc effect in the vehicle data from the two laboratories meant that it was not possible to use cross-lab controls. In the case of historical controls from the same laboratory, these could be used in place of the contemporary controls in determining a treatment's effect. There appeared to be an advantage in using larger (≥18) group sizes for historical controls. These data support the opportunity of using historical controls to reduce the number of animals used in new cardiovascular studies.

Concentration-QTc modeling of sitravatinib in patients with advanced solid malignancies.

Sitravatinib (MGCD516) is an orally available, small molecule, tyrosine kinase inhibitor that has been evaluated in patients with advanced solid tumors. Concentration-corrected QT interval (QTc; C-QTc) modeling was undertaken, using 767 matched concentration-ECG observations from 187 patients across two clinical studies in patients with advanced solid malignancies, across a dose range of 10-200 mg, via a linear mixed-effects (LME) model. The effect on heart rate (HR)-corrected QT interval via Fridericia's correction method (QTcF) at the steady-state maximum concentration (Cmax,ss) for the sitravatinib proposed therapeutic dosing regimen (100 mg malate once daily [q.d.]) without and with relevant intrinsic and extrinsic factors were predicted. No significant changes in HR from baseline were observed. Hysteresis between sitravatinib plasma concentration and change in QTcF from baseline (ΔQTcF) was not observed. There was no significant relationship between sitravatinib plasma concentration and ΔQTcF. The final C-QTc model predicted a mean (90% confidence interval [CI]) ΔQTcF of 3.92 (1.95-5.89) ms and 2.94 (0.23-6.10) ms at the proposed therapeutic dosing regimen in patients with normal organ function (best case scenario) and patients with hepatic impairment (worst-case scenario), respectively. The upper bounds of the 90% CIs were below the regulatory threshold of concern of 10 ms. The results of the described C-QTc analysis, along with corroborating results from nonclinical safety pharmacology studies, indicate that sitravatinib has a low risk of QTc interval prolongation at the proposed therapeutic dose of 100 mg malate q.d.

Respiratory Responses to Single Oral Administration of Taurine in Sprague-Dawley Rats.

Taurine is a nonessential amino acid that has been increasingly consumed due to its various beneficial biological effects. Excessive taurine intake has been linked to the positive regulation of inflammatory responses and endoplasmic reticulum stress through the modulation of intracellular calcium levels. However, research on the potential adverse effects of taurine consumption on the respiratory system is limited. To address this, we investigated the respiratory responses of 6-week-old male Sprague-Dawley rats to taurine administered orally at 0, 100, 200, and 400 mg/kg. Respiratory rate, tidal volume, and minute volume were monitored in accordance with the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) Harmonized Tripartite Guideline S7A for Safety Pharmacology Studies for Human Pharmaceuticals. We found that taurine administration did not significantly alter respiratory rate or tidal volume; however, a significant increase in minute volume was observed 6 h after administration of 200 mg/kg taurine.

Abstract 3315: Preclinical studies of TSN1611, a potent, selective, and orally bioavailable KRASG12D inhibitor

Abstract Background: KRAS mutations are the most frequently encountered driver oncogene, involved in ~25% of all human cancers [1,2]. KRASG12D is the predominant KRAS mutation isoform, detected in approximately 35% of pancreatic cancer, 13% of colorectal cancer, and 5% of NSCLC [3]. Compared to KRASG12C, targeting KRASG12D has proven to be more challenging since the target protein lacks a reactive amino acid residue for irreversible inhibitory modification by a ligand. Herein, we disclose TSN1611, a potent and selective KRASG12D inhibitor, which possesses favorable oral PK profiles and demonstrates significant in vitro and in vivo anti-tumor activity in various KRASG12D-mutant models. Method: Biochemical HTRF assay was used to measure the inhibition of TSN1611 to both GDP-bound and GTP-bound state of KRASG12D. Biophysical SPR method was used to directly measure the binding of TSN1611 to GDP-bound KRASG12D and KRASWT. Cell based activities were evaluated in a series of in vitro cell proliferation assay utilizing Ba/F3 cells engineered with KRASG12D or non-KRASG12D mutations and tumor cell lines harboring KRASG12D mutation. Human cancer cell-derived xenograft models of HPAC (pancreatic) and GP2D (colorectal) were used to evaluate its in vivo antitumor effect. in vitro and in vivo PK studies were performed in mouse, rat, and dog. Systematic nonclinical safety evaluations, including safety panel screen testing, safety pharmacology studies, and repeat-dose toxicity studies were carried out to assess its preliminary toxicity profile. Results: TSN1611 inhibited both active (GTP-bound) and inactive (GDP-bound) forms of KRASG12D protein at IC50 1.23 and 1.49 nM, respectively; the KD value of its direct binding to KRASG12D protein is 1.93 pM in SPR assay. TSN1611 demonstrated potent anti-proliferation activity against several tumor cell lines harboring KRASG12D mutation, and excellent selectivity over cells of NRAS, HRAS, and other KRAS isoforms. It also showed dose-dependent anti-tumor efficacy in GP2D and HPAC models. Mechanism of action studies concluded that the antitumor effect of TSN1611 is resulted from its effective inhibition of KRAS signaling pathway. Oral bioavailability and safety profile across multiple species supported its further development. Conclusion: TSN1611 is a selective KRASG12D inhibitor. It exhibited excellent selectivity and activity both in vitro and in vivo; it demonstrated favorable physicochemical properties, oral PK profiles, and brain penetration potential; it also showed acceptable margins of safety. The preclinical data supports further development. Pending regulatory submission and review, the phase I/II study is planned to start in H1 of 2024.

Abstract 4649: BLX-3030, a potent, selective, orally available small molecule CDK9 inhibitor for aggressive variant prostate cancers

Abstract Background: The use of novel, potent targeted therapies in prostate cancers has led to the development of highly aggressive variant cancers, including neuroendocrine prostate cancer (NEPC). Gene amplification of N-MYC and C-MYC oncogenes leads to its overexpression in NEPC and mCRPC patients, highly prevalent in these lethal subtypes of cancers detected in 2% of all Prostate Cancers (PCa) and over 10-17% of mCRPC patients. N-MYC is a transcriptional target of CDK9, which acts as an oncogenic driver sufficient to transform human-derived prostate cancer to take on NEPC phenotypic changes resulting in a more aggressive disease identified in late-stage human PCa patients. Additionally, N-MYC and C-MYC are required for tumor drug resistance, and their downregulation through CDK9 inhibition lowers tumor growth. Our efforts have demonstrated that targeting both N-MYC and C-MYC as a driver of NEPC and mCRPC with highly selective CDK9 inhibitor BLX-3030 is a viable approach for therapeutic intervention of mCRPC and NEPC. Materials and Methods: Our empirical data-driven AI/ML MolecuLernTM fragment library, workflows, LigEdit design strategies, and hit2-lead optimization methods are employed. In vitro experiments include kinase glo, cell titer glo, selectivity profiler, ADME-Tox, FACS/apoptosis, cell migration, live cell imaging, immunofluorescent, western blot, combination studies and in vivo experiments including PK, prostate tumor models, 7-day tox, BLX-3030 non (GMP) scaleup and safety pharmacology experiments conducted. Results: We synthesized a series of novel small molecule CDK9 inhibitors that reversibly bind to CDK9, competitively block the ATP site with an IC50 of 1.06 nM, and elicit pharmacological responses in N-MYC, C-MYC, and other prostate cancer cells in vitro and in vivo. We studied the CDK9 N-MYC expression detected in PC-3, DU-145, LNCaP, and in LASCPC-01, NCI-H660, and 22RV1 cell lines. BLX-3030 exhibited potent cellular efficacy with an IC50 of 22 to 590 nM in PC cell lines and in N-MYC expressed cells had an activity of 76, 470, and 132 nM respectively, and reduced pCDK9, C-MYC, Mcl-1, N-MYC and its downstream RNA Pol II (Ser-2) and pAR (Ser-81) dose-dependently. BLX-3030 exhibits in vivo antitumor activity in LASCPC-01, 22RV1, and C4-2 prostate cancer mouse models. Several ADME-Tox, MTD, dose range finding, hERG and other in vivo safety pharmacology experiments have advanced BLX-3030 to the IND enabling studies. Conclusions: BLX-3030 is currently being investigated in non-clinical toxicology, toxicokinetic, and core battery of safety pharmacology studies including the assessment of effects on cardiovascular, central nervous, and respiratory systems. Citation Format: Zhaoang li, Chenyu Lin, Kyle Medley, Hariprasad Vankayalapati, David J. Bearss. BLX-3030, a potent, selective, orally available small molecule CDK9 inhibitor for aggressive variant prostate cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4649.

Preclinical Studies Support the Clinical Development of LP-284 in Relapsed and Refractory B-Cell Lymphomas

Genomic instability, a hallmark of many cancers, often results from corrupted DNA damage response/repair (DDR) pathways. Targeting DDR deficiencies in cancer therapy has been successful in solid tumors with dysfunctional homologous recombination repair (HR). However, while less recognized, lymphomas also carry DDR defects such as HR deficiency (HRD) and can account for approximately 18% of all lymphomas. LP-284 is a fully synthetic DNA-damaging agent that induces double-stranded DNA breaks and displays elevated potency in cancer cells with HRD or transcription-coupled nucleotide excision repair defects, including multiple advanced B-cell lymphomas. In preclinical pharmacology studies, the mantle cell lymphoma (MCL) xenograft tumor mouse model derived from JeKo-1, which has mutated TP53 and checkpoint kinase 2 (CHEK2), an HRD score of 46, and was refractory to ibrutinib and bortezomib, showed near complete response after LP-284 treatment. It is noteworthy that 40~50% of MCL patients may be HRD due to the presence of mutations in the ataxia-telangiectasia mutated (ATM) gene. HRD is also likely to be prevalent in high-grade lymphomas, as IGH/MYC translocation or BCL2 expression has been reported to be associated with HR inhibition. Studies of LP-284 in the MYC/BCL2 dual-translocated OCILY1 tumor xenograft model have shown a robust efficacy profile with an average of 99% tumor growth inhibition. Key pharmacokinetic studies demonstrated that LP-284 is neither a substrate nor modulator of major CYP-450 enzymes, multi-drug resistance transporters, renal drug transporters, or hepatic drug transporters. Safety pharmacology studies indicated that LP-284 does not inhibit hERG potassium channel and has a low potential to affect cardiovascular functions. Toxicology repeat dose studies of LP-284 in Sprague Dawley rats and Beagle dogs, using intravenous infusion on Days 1, 8, and 15 in a 28-day cycle, were generally well tolerated with notable adverse effects in Beagle dogs consisting mainly of reversible hematologic toxicity and testicular toxicity. The highest non-severely toxic dose (HNSTD) in dogs was considered to be 0.4 mg/kg/dose. Overall, based on its impressive preclinical anti-tumor efficacy profile, low drug-drug interaction liability, and findings from toxicological studies, a Phase 1 study is currently planned with LP-284 to assess its safety, tolerability, pharmacokinetics, and clinical activity in patients with relapsed or refractory B-cell lymphoma. Clinical development will be informed by an emphasis on patient selection strategy based on DDR/HR biomarkers.

Preclinical Safety Assessment of Gadopiclenol: A High-Relaxivity Macrocyclic Gadolinium-Based MRI Contrast Agent.

Gadopiclenol is a new high-relaxivity macrocyclic gadolinium-based contrast agent for magnetic resonance imaging of the central nervous system and other body regions. The product has been approved by US Food and Drug Administration and is currently being evaluated by European Medicines Agency. For risk assessment of the single diagnostic use in humans, the safety profile of gadopiclenol was evaluated with a series of preclinical studies. With exception of dose-ranging studies, all safety pharmacology and toxicology studies were performed in compliance with Good Laboratory Practice principles. Safety pharmacology studies were conducted to assess potential effects on cardiovascular (in vitro and in dogs), respiratory (in rats and guinea pigs), neurological (in rats), and renal endpoints (in rats). Toxicology studies were also performed to investigate acute toxicity (in rats and mice), extended single-dose (in rats and dogs) and repeated-dose toxicity (in rats and dogs), reproductive (in rats), developmental (in rats and rabbits) and juvenile toxicity (in rats), as well as genotoxicity (in vitro and in rats), local tolerance (in rabbits), potential immediate hypersensitivity (in guinea pigs), and potential tissue retention of gadolinium (in rats). Safety pharmacology studies conducted at high intravenous (IV) doses showed a satisfactory tolerance of gadopiclenol in the main body systems. After either single or repeated IV dosing (14 and 28 days) in rats and dogs, gadopiclenol was well tolerated even at high doses. The no-observed-adverse-effect level values (ie, the highest experimental dose without adverse effects) representing between 8 times in rats and 44 times in dogs (based on the exposure), the exposure achieved in humans at the intended diagnostic dose, provide a high safety margin. No or only minor and reversible effects on body weight, food consumption, clinical signs, clinical pathology parameters, or histology were observed at the highest doses. The main histological finding consists in renal tubular vacuolations (exacerbated after repeated exposure), which supports a well-known finding for this class of compounds that has no physiological consequence on kidney function. Reproductive toxicity studies showed no evidence of effects on reproductive performance, fertility, perinatal and postnatal development in rats, or reproductive development in rats or rabbits. The safety profile of gadopiclenol in juvenile rats was satisfactory like in adults. Gadopiclenol was not genotoxic in vitro in the Ames test, a mouse lymphoma assay, and a rat in vivo micronucleus test. There were no signs of local intolerance at the injection site after IV and intra-arterial administration in rabbits. However, because of minor signs of intolerance after perivenous administration, misadministration must be avoided. Gadopiclenol exhibited no signs of potential to induce immediate hypersensitivity in guinea pigs. High safety margins were observed between the single diagnostic dose of 0.05 mmol/kg in humans and the doses showing effects in animal studies. Gadopiclenol is, therefore, well tolerated in various species (mice, rats, dogs, rabbits, and guinea pigs). All observed preclinical data support the clinical approval.

Photobac derived from bacteriochlorophyll-a shows potential for treating brain tumor in animal models by photodynamic therapy with desired pharmacokinetics and limited toxicity in rats and dogs

Photobac is a near infrared photosensitizer (PS) derived from naturally occurring bacteriochlorophyll- a, with a potential for treating a variety of cancer types (U87, F98 and C6 tumor cells in vitro). The main objective of the studies presented herein was to evaluate the efficacy, toxicity and pharmacokinetic profile of Photobac in animals (mice, rats and dogs) and submit these results to the United States Food and Drug Administration (US FDA) for its approval to initiate Phase I human clinical trials of glioblastoma, a deadly cancer disease with no long term cure. The photodynamic therapy (PDT) efficacy of Photobac was evaluated in mice subcutaneously implanted with U87 tumors, and in rats bearing C6 tumors implanted in brain. In both tumor types, the Photobac-PDT was quite effective. The long-term cure in rats was monitored by magnetic resonance imaging (MRI) and histopathology analysis. A detailed pharmacology, pharmacokinetics and toxicokinetic study of Photobac was investigated in both non-GLP and GLP facilities at variable doses following the US FDA parameters. Safety Pharmacology studies suggest that there is no phototoxicity, cerebral or retinal toxicity with Photobac. No metabolites of Photobac were observed following incubation in rat, dog, mini-pig and human hepatocytes. Based on current biological data, Photobac-IND received the approval for Phase-I human clinical trials to treat Glioblastoma (brain cancer), which is currently underway at our institute. Photobac has also received an orphan drug status from the US FDA, because of its potential for treating Glioblastoma as no effective treatment is currently available for this deadly disease.

The "One-Step" approach for QT analysis increases the sensitivity of nonclinical QTc analysis.

Whether a compound prolongs cardiac repolarization independent of changes in beat rate is a critical question in drug research and development. Current practice is to resolve this in two steps. First, the QT interval is corrected for the influence of rate and then statistical significance is tested. There is renewed interest in improving the sensitivity of nonclinical corrected QT interval (QTc) assessment with modern studies having greater data density than previously utilized. The current analyses examine the effects of moxifloxacin or vehicle on the QT interval in nonhuman primates (NHPs) using a previously described one-step method. The primary end point is the statistical sensitivity of the assessment. Publications suggest that for a four animalcrossover (4 × 4) in NHPs the minimal detectable difference (MDD) is greater than or equal to 10 ms, whereas in an eight animal crossover the MDD is ~6.5 ms. Using the one-step method, the MDD for the four animal NHP assessments was 3 ms. In addition, the one-step model accounted for day-to-day differences in the heart rate and QT-rate slope as well as drug-induced changes in these parameters. This method provides an increase in the sensitivity and reduces the number of animals necessary for detecting potential QT change and represents "best practice" in nonclinical QTc assessment in safety pharmacology studies.

P24-01: A Review of the Incidence of Common Arrhythmias in Bama Minipigs observed in Stand-alone Safety Pharmacology and General Toxicology Studies

P24-01: A Review of the Incidence of Common Arrhythmias in Bama Minipigs observed in Stand-alone Safety Pharmacology and General Toxicology Studies