Preclinical Toxicology Studies Research Articles

Reprogramming tumor immune microenvironment by milbemycin oxime results in pancreatic tumor growth suppression and enhanced anti-PD-1 efficacy

Pancreatic ductal adenocarcinoma (PDAC) has a survival rate of 12% and multiple clinical trials testing anti-PD1 therapies against PDAC have failed suggesting a need of novel therapeutic strategy. In this study, we evaluated the potential of milbemycin oxime (MBO), an antiparasitic compound, as an immunomodulatory agent in PDAC. Our results show that MBO inhibited growth of multiple PDAC cell lines by inducing apoptosis. In vivo studies showed that oral administration of 5 mg/kg MBO inhibited PDAC tumor growth in both subcutaneous and orthotopic models by 49 and 56%, respectively. Additionally, MBO treatment significantly increased the survival of tumor-bearing mice by 27 days as compared to control group. Interestingly, tumors from MBO-treated mice had increased infiltration of CD8+ T cells. Notably, depletion of CD8+ T cells significantly reduced the anti-tumor efficacy of MBO in mice. Further, MBO significantly augmented the efficacy of anti-PD1 therapy, and the combination treatment resulted in a greater proportion of active cytotoxic T cells within the TME. MBO was safe and well tolerated in all our preclinical toxicological studies. Overall, our study provides a new direction for the use of MBO against PDAC and highlights the potential of repurposing MBO for enhancing anti-PD1 immunotherapy.

Intranasal administration of a synthetic TLR4 agonist INI-2004 significantly reduces allergy symptoms following therapeutic administration in a murine model of allergic sensitization.

Atopic diseases have been steadily increasing over the past decades and effective disease-modifying treatment options are urgently needed. These studies introduce a novel synthetic Toll-like receptor 4 (TLR4) agonist, INI-2004, with remarkable efficacy as a therapeutic intranasal treatment for seasonal allergic rhinitis. Using a murine airway allergic sensitization model, the impact of INI-2004 on allergic responses was assessed. One or two intranasal doses of INI-2004 significantly reduced airway resistance, eosinophil influx, and Th2 cytokine production - providing strong evidence of allergic desensitization. Further investigations revealed that a liposomal formulation of INI-2004 exhibited better safety and efficacy profiles compared to aqueous formulations. Importantly, the liposomal formulation demonstrated a 1000-fold increase in the maximum tolerated intravenous dose in pigs. Pre-clinical GLP toxicology studies in rats and pigs confirmed the safety of liposomal INI-2004, supporting its selection for human clinical trials. These findings lay the groundwork for the ongoing clinical evaluation of INI-2004 in allergic rhinitis as a stand-alone therapy for individuals poly-sensitized to multiple seasonal allergens. The study underscores the significance of innovative immunotherapy approaches in reshaping the landscape of allergic rhinitis management.

A multi-center, open-label phase 1/1b dose finding, safety, and pharmacokinetic study of MBRC-101, an Anth-EphA5 monomethyl auristatin (MMAE) antibody drug conjugate, in advanced refractory solid tumors.

TPS3161 Background: EphA5 receptor is a member of the Ephrin receptor tyrosine kinase family. Several lines of compelling nonclinical evidence indicate EphA5 is a novel and selective target for solid tumor-directed therapy. Expressed only minimally in normal tissues, it is highly expressed in non-small cell lung carcinoma (NSCLC), head and neck squamous cell carcinoma (HNSCC), and breast, colorectal, pancreatic, gastric, and hepatic malignancies. MBRC-101 is a novel antibody drug conjugate (ADC) composed of an anti-EphA5 antibody conjugated to an MMAE payload (drug-to-antibody ratio of 4) through a valine citrulline cleavable linker. In pre-clinical toxicology studies and testing against a variety of cell-derived (CDX) and patient-derived (PDX) xenograft solid tumor models expressing EphA5--including NSCLC, triple negative breast cancer (TNBC), and HNSCC--MBRC-101 demonstrated favorable safety profiles and robust anti-tumor activity. Methods: This first-in-human, Phase 1/1b, multicenter, open-label study is examining the safety and efficacy of MBRC-101 in patients with advanced metastatic solid tumors refractory to standard treatment. Phase 1 will identify potential optimal biologically relevant doses (OBRD) and the maximum tolerated dose (MTD) of MBRC-101 at one or more dosing regimens. Phase 1b will evaluate the safety and preliminary clinical activity of MBRC-101 at potential OBRDs. Phase 1 will enroll patients (n ≈ 30) with advanced or metastatic solid tumors. EphA5 expression will not be required for enrollment into Phase 1 but will be assessed retrospectively. A modified toxicity probability interval (mTPI-2) method will guide dose escalation using a pre-specified decision matrix. The primary endpoints are MTD, dose limiting toxicities (DLTs), treatment emergent adverse events (TEAEs), and clinical laboratory tests. Phase 1b (n ≈ 60 patients) will include 3 expansion cohorts (n ≈ 20 patients per cohort): Cohort A, NSCLC; Cohort B, triple negative or HR+/HER2- breast cancer; and Cohort C, solid tumors irrespective of histologic tissue type (i.e., tumor agnostic) excluding NSCLC and breast cancer. Expression of EphA5 in primary or metastatic tumor tissue will not be required for enrollment into cohorts A and B but will be required for Cohort C. The primary endpoints are TEAEs, clinical laboratory tests, and investigator-assessed objective response rate (ORR) by RECIST v1.1 and clinical evaluation. Secondary endpoints for Ph1 and 1b include PK analytes and EphA5 expression as determined by immunohistochemistry (IHC). A Safety Review Committee will monitor safety at each dose escalation in Phase 1 and at regular intervals throughout Phase 1b. Clinical trial information: NCT06014658 .

Abstract CT088: EVT801, a novel selective VEGFR-3 inhibitor targeting tumor angiogenesis, is pursuing dose escalation stage of phase I first-in-human study

Abstract Background: EVT801 is a highly selective, orally available VEGFR3 inhibitor that modulates tumor angiogenesis without inducing hypoxia, one of the main causes of cancer-associated immunosuppression. EVT801 has shown compelling efficacy as single agent in multiple in vivo models. In addition, combination of EVT801 and Immune Checkpoint Therapy (ICT) agents shows additive effects and thus holds promises for combination treatment without induction of hypoxia-induced immunosuppression. Clinical trial design: A phase I clinical study (NCT05114668) is underway to evaluate safety, tolerability, pharmacokinetics of EVT801 and explore patient characterization which is key for further development. The phase I trial consists in two sequential stages. During the first stage, currently ongoing, EVT801 is orally administered to patients with advanced solid tumors in a multiple ascending dose study using an accelerated 3+3 design (1 patient per dose until grade 2 toxicities are observed) in up to 48 patients in 8 dose levels. The primary objective is to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Stage 2 will focus on validation of this RP2D in two 6-patient cohorts diagnosed with 2 indications. In addition to conventional measures of safety, tolerability, efficacy, and pharmacokinetics, the phase I study employs a rich suite of biomarkers analysis using histology, transcriptomics and immunomonitoring to provide early insights into the pharmacological activity of EVT801. At end of September 2023, 20 patients have been treated in five different cohorts for EVT801 doses ranging from 50mg QD to 400mg BID. At this date, only 1 dose limiting toxicity was declared at the higher dose. Conclusion: Collection of safety data on these first enrolled patients showed no safety alert which allows further dose escalation and reinforces the good safety profile of EVT801 observed during the preclinical toxicology studies. Citation Format: Carlos Gomez-Roca, Philippe Cassier, Michael Fitzgerald, Lise Davenne, Cristina Costantin, Philippe Rochaix, Jean-Pierre Delord, John Friend, Andrea Nizzardo, Alessia Tagliavini, Marco Pergher, Pierre Fons, Marie Mandron. EVT801, a novel selective VEGFR-3 inhibitor targeting tumor angiogenesis, is pursuing dose escalation stage of phase I first-in-human study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT088.

Abstract LB126: Generation of a novel ROR1 x CD3 bispecific T-cell engager for better tumor killing and minimal cytokine release

Abstract Receptor tyrosine kinase-like orphan receptor 1 (ROR1) expression is a highly specific tumor associated antigen expressed in multiple hematological malignancies and solid tumors. EMB-07 is a novel monovalent asymmetrical tandem Fab (MAT-Fab) antibody composed of two different Fab fragments targeting ROR1 and CD3ε respectively, and a “knob-in-hole” Fc fragment maintaining FcRn binding and Ig-like pharmacokinetics in vivo. To avoid light chain miss-pairing, the anti-ROR1 light chain was directly connected to the N-terminus of the anti-CD3 heavy chain. The ROR1 binding arm has a high affinity of 0.52 nM and recognizes a membrane distal epitope, which is different from a reference BiTE molecule currently in clinical trial. In comparison with this BiTE molecule, EMB-07 showed similar tumor killing efficacy to ROR1 expressing tumor cell lines while it induced much lower levels of cytokines both in vitro and in vivo. Moreover, comparing with a clinical stage ROR1-vc-MMAE ADC, EMB-07 demonstrated ~500-fold increased tumor lysis potency in vitro. In PD-1 resistant tumor xenograft mice models, EMB-07 showed potent tumor growth inhibition and synergistic activity in combination with PD-1 blockade. In a preclinical GLP toxicological study, EMB-07 was well tolerated in cynomolgus monkeys with no evidence of lethality, life-threatening toxicity, or obvious EMB-07-related macroscopic and histopathological adverse findings up to 50 mg/kg. By using a highly specific IHC clone, we validated membrane-associated ROR1 expression in multiple tumor types, including triple negative breast cancer, ovarian cancer, endometrial cancer, lung adenocarcinoma, and pancreatic cancer, while the observation of its expression in normal tissues is very limited. This study supports the clinical development of EMB-07 for treating multiple solid tumors with ROR1 expression. A FIH study of EMB-07 in locally advanced/metastatic solid tumors or relapse/refractory lymphoma is currently ongoing (NCT05607498). Citation Format: Danqing Wu, Shiyong Gong, Xuan Wu, Gaowa Naren, Liqin Dong, Stephan Lensky, Chengbin Wu. Generation of a novel ROR1 x CD3 bispecific T-cell engager for better tumor killing and minimal cytokine release [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB126.

Abstract 1059: Biomarkers analysis on samples from patients in EVT801 clinical trial: Patient characterization and immunomonitoring

Abstract Introduction: EVT801 is a highly selective small molecule inhibitor of VEGFR3 that acts by inducing tumor (lymph)-angiogenesis normalization in and around the tumor. EVT801 has shown compelling activity in a wide range of cancer models showing a decrease of tumor hypoxia and an increase of CD8pos T-cells infiltration into the tumor micro-environment. EVT801 was well-tolerated in preclinical toxicology studies. A phase I study is underway focusing primarily on understanding the safety, tolerability, and pharmacokinetics of EVT801 across a range of doses (NCT05114668). Methods: The first stage of the phase I trial aims to determine the maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) for EVT801. Clinical samples from enrolled patients have been collected to explore preliminary signals of the biological activity of the drug and characterize tumor phenotypes. Patient characterization includes histology and mRNA signature in archival biopsies. Target engagement and pharmacodynamics effects are investigated by immunomonitoring as well as assessment of a defined set of proteins as markers of inflammation and angiogenesis as identified in preclinical in vivo models. Conclusion: Our first biomarkers analyses on a subpopulation of patients with High Grade Serous Ovarian Cancer (HGS-OC) enrolled in the first stage of the study showed that levels of VEGFR3 expression had a negative correlation with CD8 positive T-cells infiltration in the tumor microenvironment and a tendency to positive correlation with a PD1 mAb resistance signature. VEGFR3 expression also tends to be correlated with higher levels of hypoxia (CAIX labelling). Our working hypothesis is that patients with hypoxic HGS-OC tumors with high VEGFR3 expression may benefit from EVT801 treatment; this will need to be reinforced by inclusion of additional patients in dedicated PD biomarkers cohorts during stage 2 of the clinical trial. Citation Format: Lise Davenne, Michael Fitzgerald, Pierre-Benoit Ancey, Oona Delpuech, Céline Poussereau-Pomié, Michael Esquerre, Michael R. Paillasse, Marie Mandron, Philippe Rochaix, Maha Ayyoub, Clara Maria Scarlata, Christine Caux, Christophe Caux, Philippe Cassier, Carlos Gomez-Roca, Jean-Pierre Delord, John Friend, Pierre Fons. Biomarkers analysis on samples from patients in EVT801 clinical trial: Patient characterization and immunomonitoring [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 1059.

Abstract 6773: Tissue engineered colorectal cancer microspheres for drug screening

Abstract Three-dimensional (3D) disease models have garnered widespread interest for use in later stages of the drug discovery process, such as preclinical efficacy and toxicology studies, due to their pathophysiologically relevant properties. However, there is a need and opportunity for 3D cancer models to be used earlier in the drug screening process. To meet this need, the 3D models must strike a balance between throughput, which includes scalability and uniformity, and physiological relevance, such as the ability to modulate key attribute of the tumor microenvironment. Here we report the creation of 3D colorectal cancer (CRC) tissue models, referred to as VivoSpheres, and demonstrated their relevance to cancer drug screening. The VivoSphere production platform couples tissue engineering toolkits with microfluidics, enabling the scalable production of engineered cancer microspheres. The model supports the long-term maintenance of the cancer cell phenotype. In a preliminary study, we were able to generate more physiologically relevant drug responses. We formed CRC VivoSpheres by encapsulating HT-29 CRC cells within poly(ethylene glycol)-fibrinogen hydrogel microspheres using our previously developed microfluidic platform. CRC VivoSpheres were rapidly produced with high cell densities (20 × 106 cells/ml) and high uniformity on day 0 with a coefficient of variation (COV) < 7%. This high uniformity was maintained for 15 days (COV ≤ 10%), which is critical for long-term dose studies. The cells maintained high viability and showed high proliferative capability with a significant increase in colony size and expression of Ki67 up to day 29. The encapsulated cells maintained the CRC phenotype over time with the expression of CD44 (cancer stem cell marker) and CK20 (CRC marker). After establishing shipping conditions that maintained cell viability for remote use, the HT-29 VivoSpheres were shipped to the oncology team at Southern Research for drug testing. The CRC VivoSpheres were treated with DMSO, GANT61, and SRI-38832, the latter two of which are GLI1 inhibitors. Phase contrast images and western blot were used to assess the response of CRC VivoSpheres to the treatments. Oncogenic GLI1 transcription activity and NBS1 overexpression have been found to contribute to chemotherapeutic resistance, negating the anti-tumor effects of 5-fluorouracil. While 2D cultured HT-29s responded to treatment with GANT61, HT-29 VivoSpheres continued to express NBS1 following GANT1 treatment, but downregulated NBS1 in response to the GLI1 inhibitor SRI-38832, which is the same response Southern Research has seen in in vivo tumor models. In conclusion, we have developed tissue-engineered 3D CRC models that hold promise for use in drug screening. These models have demonstrated an initial capability to reproduce the CRC phenotype and mimic in vivo drug response. Citation Format: Yuan Tian, Mohammadjafar Hashemi, Benjamin Anbiah, Ruowen Zhang, Iman Hassani, Rebecca Boohaker, Elizabeth Lipke. Tissue engineered colorectal cancer microspheres for drug screening [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 6773.

Abstract 1891: Preclinical characterization of ADRX-0706: A next-generation anti-Nectin-4 antibody-drug conjugate with improved therapeutic window

Abstract Nectin-4 is a well validated tumor target, which is highly expressed in several solid cancers such as urothelial, head-and-neck, breast, lung, pancreatic, ovarian, and cervical cancer, while expression in normal tissues is limited. A first-generation antibody-drug conjugate targeting Nectin-4, called enfortumab vedotin-ejfv (EV), was granted accelerated FDA approval in 2019 for urothelial cancers, and is currently approved for frontline therapy in cisplatin-ineligible patients with locally advanced or metastatic urothelial carcinoma, providing groundbreaking improvement in patient survival. However, clinical use of EV has also revealed safety-driven limitations, which result in reduced and/or interrupted drug exposures impacting efficacy. To overcome these limitations in therapeutic window and to maximize on the potential of Nectin-4 as a tumor target beyond urothelial cancers, Adcentrx has developed ADRX-0706, a Nectin-4-targeting next-generation ADC with a drug-antibody ratio of 8. ADRX-0706 is comprised of a novel fully human IgG1k monoclonal antibody linked to an optimized tubulin inhibitor payload AP052 through a proprietary cleavable linker. ADRX-0706 has strong binding affinity and selectively induces cytotoxicity in Nectin-4-expressing tumor cells. Importantly, ADRX-0706 is designed to have improved bystander effect, which allows tumor regression even in cases of heterogeneous Nectin-4 expression. This translates to superior in vivo efficacy of ADRX-0706 over EV in multiple mouse xenograft models of other indications beyond bladder cancer. In a mouse clinical trial of patient-derived cervical cancers with a range of Nectin-4 expression levels, ADRX-0706 reaches a 73% ORR. Since peripheral neuropathy is a main platform toxicity for this payload class, ADRX-0706 is assessed in an in vitro co-culture model to evaluate its neurotoxic potential. While EV displays a 75% decrease in neurite outgrowth, ADRX-0706 strikingly has no impact at concentrations up to 1mg/ml, suggesting a lower risk of peripheral neuropathy in humans for ADRX-0706. In preclinical repeat dose toxicology study, ADRX-0706 reaches an HNSTD of 18mg/kg in NHPs well above therapeutic exposures in mouse pharmacology studies, indicating a tremendous increase in the therapeutic index compared to EV. In summary, the highly selective and potent anti-tumor activity in multiple tumor types and wide preclinical therapeutic index of ADRX-0706 support clinical evaluation of this next generation anti-Nectin-4 ADC. ADRX-0706 is currently in a phase 1a/b study (NCT06036121). Citation Format: Andrew M. Hau, Maria Shahmoradgoli, Dong Jun Lee, Wes Sisson, Anna Wang, Peter P. Challita, Erin Nye, Mario M. Kuo, Alexis Mahloch, Monica Leung, Oscar Betancourt, Alexander Chu-Kung, Maojun Guo, Hui Li, Sabine Rottmann, Pia M. Challita-Eid. Preclinical characterization of ADRX-0706: A next-generation anti-Nectin-4 antibody-drug conjugate with improved therapeutic window [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 1891.

An assessment of a GMP schistosomiasis vaccine (SchistoShield®).

Schistosomiasis is a neglected tropical disease that puts over 200 million people at risk, and prevention options are sparse with no approved vaccine. Our vaccine candidate, SchistoShield®, is based on an approximately 87 kDa large subunit of calcium activated neutral protease - termed Sm-p80 - combined with a potent TLR4 agonist-based adjuvant. SchistoShield® has been shown to prevent disease throughout the parasitic life cycle - including egg, juvenile, and adult worm stages - in numerous animal models up to and including baboons. SchistoShield® has been shown safe in both preclinical toxicology studies in rabbits and in a Phase 1 clinical trial in the USA. A Phase 1b trial was initiated in 2023 in endemic regions of Africa, and to date no serious safety signals have been reported. In preparation for large-scale Phase 2 clinical trials and eventual vaccine deployment, the Sm-p80 antigen production process has been transferred to a manufacturing organization, Quratis Corporation in South Korea, which specializes in preparation of vaccines for large-scale European and African trials. The process of scaling from our current production level of ~2000 vaccine doses, to a process that will generate more than 100 million doses has required multiple improvement steps in the process including fermentation, downstream purification of the protein antigen, lyophilization, and fill and finish. In this study, we detail the large-scale production process of the SchistoShield® protein product by Quratis. In addition, an effort was made to analyze and compare the Quratis-made lot of Sm-p80, referred to as QTP-105, to the cGMP lot of Sm-p80 which is in use in human trials in the USA and Africa, referred to as Sm-p80 DP (made in USA). We show that QTP-105 demonstrates excellent potency, purity, identity, and endotoxin levels compared to our Phase 1 Sm-p80 DP and is suitable for use in Phase 2 studies and beyond.

Evaluation of Preclinical Toxicity of Methanolic Extract of Sargassum tenerrimum using the Zebrafish Model

Introduction: In the field of biomedicine, marine algae have gained significant attention due to the abundance of bioactive compounds they contain. However, studies on the chronic toxicity of algae are limited. Aim: To evaluate the in-vitro, in-vivo acute, and subchronic toxicity of Sargassum tenerrimum (S. tenerrimum) in an adult zebrafish model. Materials and Methods: The current preclinical toxicological interventional study was conducted at the Department of Pharmacology, Sri Ramachandra Medical College and Research Institute, SRIHER, Chennai, Tamil Nadu, India, in September 2022. The algae S. tenerrimum was extracted with methanol using Soxhlet extraction. In-vitro toxicity of S. tenerrimum was performed using the MTT (3-[4,5-dimethylthiazol-2-yl]- 2,5 diphenyl tetrazolium bromide) assay on the SH-SY5Y cell line. Acute toxicity was carried out for 96 hours according to Organisation for Economic Cooperation and Development (OECD) 203 guidelines, and subchronic toxicity was carried out for 14 days on the zebrafish model using the immersion method. Additionally, histopathological changes were observed after the acute toxicity study, and the Lethal Concentration 50 (LC50) value was analysed. Results: The MTT assay of the methanolic extract of S. tenerrimum revealed an LC50 value of 140.014 μg/mL. An acute toxicity study conducted on zebrafish for 96 hours showed an LC50 value of 504.669 mg/L. Subchronic toxicity was done for 14 days, and on the 14th day of exposure, the LC50 value was found to be 404.196 mg/L. Histopathological changes were observed at higher concentrations (800 mg/L) of algal extract. Conclusion: The present study revealed that the methanolic extract of S. tenerrimum showed a toxic effect at higher concentrations on the zebrafish model. However, at lower concentrations, S. tenerrimum was deemed safe for further exploration of pharmacological activities in a zebrafish model.

A highly potent anti-VISTA antibody KVA12123 -a new immune checkpoint inhibitor and a promising therapy against poorly immunogenic tumors.

Immune checkpoint therapies have led to significant breakthroughs in cancer patient treatment in recent years. However, their efficiency is variable, and resistance to immunotherapies is common. VISTA is an immune-suppressive checkpoint inhibitor of T cell response belonging to the B7 family and a promising novel therapeutic target. VISTA is expressed in the immuno-suppressive tumor microenvironment, primarily by myeloid lineage cells, and its genetic knockout or antibody blockade restores an efficient antitumor immune response. Fully human monoclonal antibodies directed against VISTA were produced after immunizing humanized Trianni mice and single B cell sequencing. Anti-VISTA antibodies were evaluated for specificity, cross-reactivity, monocyte and T cell activation, Fc-effector functions, and antitumor efficacy using in vitro and in vivo models to select the KVA12123 antibody lead candidate. The pharmacokinetics and safety profiles of KVA12123 were evaluated in cynomolgus monkeys. Here, we report the development of a clinical candidate anti-VISTA monoclonal antibody, KVA12123. KVA12123 showed high affinity binding to VISTA through a unique epitope distinct from other clinical-stage anti-VISTA monoclonal antibodies. This clinical candidate demonstrated high specificity against VISTA with no cross-reactivity detected against other members of the B7 family. KVA12123 blocked VISTA binding to its binding partners. KVA12123 induced T cell activation and demonstrated NK-mediated monocyte activation. KVA12123 treatment mediated strong single-agent antitumor activity in several syngeneic tumor models and showed enhanced efficacy in combination with anti-PD-1 treatment. This clinical candidate was engineered to improve its pharmacokinetic characteristics and reduce Fc-effector functions. It was well-tolerated in preclinical toxicology studies in cynomolgus monkeys, where hematology, clinical chemistry evaluations, and clinical observations revealed no indicators of toxicity. No cytokines associated with cytokine release syndrome were elevated. These results establish that KVA12123 is a promising drug candidate with a distinct but complementary mechanism of action of the first generation of immune checkpoint inhibitors. This antibody is currently evaluated alone and in combination with pembrolizumab in a Phase 1/2 open-label clinical trial in patients with advanced solid tumors.

Results of Preclinical Animal Studies to Evaluate the Effect of Iptacopan on Pregnancy-Related Outcomes

Introduction: Iptacopan is a first-in-class, oral, selective inhibitor of factor B, a key component of the complement system alternative pathway. Inhibition of the complement system represents a potential mechanism for treatment of several complement-driven diseases including paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome. Here, we report results from the preclinical GLP toxicology studies of iptacopan on embryo-fetal development in rats and rabbits and pre- and postnatal development in rats. Methods: In the definitive embryo-fetal development studies,iptacopan was dosed orally via gavage to pregnant rats at 0, 100, 300, and 1000 mg/kg/day (N=24/group) and to pregnant rabbits at doses of 0, 100, 250, and 450 mg/kg/day (N=20/group) during the period of organogenesis (Gestation Day [GD] 6 to 17 and GD7 to 20, respectively). The progress and outcome of pregnancy were evaluated and fetuses were examined for external, visceral, and skeletal abnormalities. In a pre- and postnatal developmental toxicity study in pregnant rats, iptacopan was dosed orally via gavage at 0, 100, 300, and 1000 mg/kg/day (N=22/group) from GD6 to Lactation Day (LD) 21. The untreated offspring were allowed to mature and the effects on development, behavior, and reproductive performance were assessed. Results: In the rat embryo-fetal development study, maternal administration of iptacopan resulted in no adverse clinical observations, no effects on maternal body weights, and no adverse fetal findings. Non-adverse fetal variations of delayed ossification were observed in the skull. Two fetuses in one out of 22 litters at 1000 mg/kg/day had benign cysts on the left side of the parietal region of the head, with no impact on skeletal (skull), CNS (brain), or any other head-based structure. The no observed adverse effect level (NOAEL) for maternal toxicity and embryo-fetal development was 1000 mg/kg/day. In the definitive rabbit embryo-fetal development study, administration of iptacopan caused reduced maternal body weight gain and food consumption at 450 mg/kg/day. There were no treatment-related fetal malformations or variations. The NOAEL was 250 mg/kg/day for maternal toxicity and 450 mg/kg/day for embryo-fetal development. In the pre- and postnatal development study, no adverse findings were observed in the mated female rats during gestation, parturition, and lactation and there were no adverse effects on development of their offspring, including survival, physical development, behavior, and reproductive performance. The NOAEL for maternal (F0 generation) toxicity, maternal performance, and development of the F1 generation offspring was the highest dose of 1000 mg/kg/day. NOAEL and estimated AUC-based safety margins based on total plasma concentrations for all mentioned studies are shown in the Table. Conclusion: In nonclinical reproductive toxicity studies conducted in pregnant rats and rabbits, iptacopan was found to be generally safe with no teratogenic effects in the rat and rabbit. Estimated AUC-based safety margins were >5-fold for all developmental findings compared to exposure at the clinical dose of 200 mg twice daily. While these preclinical data do not provide definitive conclusions or guidance on the use of iptacopan in pregnant women, they do provide reassurance that there is no overt preclinical signal of embryo-fetal toxicity.

Conceptualizing the use of the clinical index of liver fibrosis, FIB-4 index, in in vivo preclinical toxicological studies

Conceptualizing the use of the clinical index of liver fibrosis, FIB-4 index, in in vivo preclinical toxicological studies

Development of ADS051, an oral, gut-restricted, small molecule neutrophil modulator for the treatment of neutrophil-mediated inflammatory diseases.

Neutrophils are an essential component of the innate immune system; however, uncontrolled neutrophil activity can lead to inflammation and tissue damage in acute and chronic diseases. Despite inclusion of neutrophil presence and activity in clinical evaluations of inflammatory diseases, the neutrophil has been an overlooked therapeutic target. The goal of this program was to design a small molecule regulator of neutrophil trafficking and activity that fulfilled the following criteria: (a) modulates neutrophil epithelial transmigration and activation, (b) lacks systemic exposure, (c) preserves protective host immunity, and (d) is administered orally. The result of this discovery program was ADS051 (also known as BT051), a low permeability, small molecule modulator of neutrophil trafficking and activity via blockade of multidrug resistance protein 2 (MRP2)- and formyl peptide receptor 1 (FPR1)-mediated mechanisms. ADS051, based on a modified scaffold derived from cyclosporine A (CsA), was designed to have reduced affinity for calcineurin with low cell permeability and, thus, a greatly reduced ability to inhibit T-cell function. In cell-based assays, ADS051 did not inhibit cytokine secretion from activated human T cells. Further, in preclinical models, ADS051 showed limited systemic absorption (<1% of total dose) after oral administration, and assessment of ADS051 in human, cell-based systems demonstrated inhibition of neutrophil epithelial transmigration. In addition, preclinical toxicology studies in rats and monkeys receiving daily oral doses of ADS051 for 28 days did not reveal safety risks or ADS051-related toxicity. Our results to date support the clinical development of ADS051 in patients with neutrophil-mediated inflammatory diseases.

P014 Safety and toxicity profile of SPL84, an inhaled antisense oligonucleotide cystic fibrosis therapeutic

The ASO field is an emerging area of drug development that targets the disease source at the RNA level, offering a promising alternative to therapies targeting downstream processes. SpliSense is developing SPL84, an inhaled ASO for the treatment of CF patients carrying the 3849 +10 kb C->T mutation. In order to move into the clinic, we performed a full battery of preclinical safety and toxicology studies with SPL84.

History of the discovery and development of Biomodulina T (InmunyVital®), a useful immunomodulator with a broad range of clinical applications.

Biomodulina T (InmunyVital®) is a thymic factor that modulates immune response and inflammation. Biomodulina T stimulates the differentiation, maturation and proliferation of T cells. Additionally, Biomodulina T improves the ability of T cells to produce cytokines, therefore enhancing T lymphocyte function. Biomodulina T stimulates the thymus gland and, thus, promotes the recovery of normal thymus size in children with thymic hypoplasia and restores the functions of immunosenescent T cells in aging people. In 1984 Rodriguez Martin RR established the laboratory of Biomodulators, where he created and developed an immunomodulatory thymic factor that he named "Biomodulina T." The biological activity of Biomodulina T was demonstrated in several studies. An extensive series of preclinical toxicological studies were conducted and these studies demonstrated that Biomodulina T is an active and safe thymic factor. Clinical trials were conducted with Biomodulina T in patients with immunodeficiency and infections, autoimmune diseases, older adults with recurrent respiratory infections, and cancer. In 1994, we obtained the approval of Biomodulina T as an immunomodulatory drug. This article identifies the milestones involved in the development of Biomodulina T. Since its discovery more than 35years ago, reports show that Biomodulina T is a modulator of immune response and inflammation that is very useful for restoring the immune system in young and elderly people with immunodeficiencies, autoimmune diseases, and infections. Biomodulina T is also useful as an immunotherapeutic agent for improving immune responses in cancer and vaccines, for reversing immunosenescence and for improving healthspan in aging.

Generation of cynomolgus monkey airway, liver ductal, and kidney organoids with pharmacokinetic functions

Over the past decades, the pre-clinical evaluation of new drugs requires toxicological screening in animal models. The development of non-animal and nonclinical screening models could potentially play a role in the prediction of human pharmacokinetics of new drug candidates. In this study, we established stable organoids of the cynomolgus monkey airway, liver ductal, and kidney that could be passaged and cryopreserved. Drug sensitivity analyses revealed that very low doses of gemcitabine and 5-fluorouridine were toxic to the airway, liver ductal, and kidney organoids. Only high doses of regorafenib were toxic to liver ductal organoids while airway organoids were resistant to all doses of pemetrexed. These organoids showed tissue-specific expression of drug-metabolizing enzymes and drug transporter genes with liver ductal organoids exhibiting the most significant expression of all drug-metabolizing enzymes and transporters. The systematic evaluation of the pharmacokinetic functions of the cynomolgus monkey kidney, liver ductal, and airway organoids could find application in the pre-clinical toxicological studies of new drugs.

Abstract LB245: ONM-501, a dual-activating polyvalent STING agonist, enhances tumor retention and demonstrates favorable preclinical safety profile

Abstract Background: The Stimulator of Interferon Genes (STING) plays a crucial role in the innate immune response. Several previous STING agonist development compounds have shown limited therapeutic efficacy in oncology clinical trials. ONM-501 is a novel STING agonist: the endogenous STING agonist 2’,3’-cyclic GMP-AMP (cGAMP) is encapsulated within PC7A micelles. PC7A induces polyvalent STING condensation and prolongs immune activation. cGAMP-PC7A nanoparticles offer a dual ‘burst’ and ‘sustained’ STING activation. The anti-tumor efficacy and pharmacodynamic analysis of ONM-501 in multiple tumor models have been demonstrated previously. Here we report the pharmacokinetic (PK) and biodistribution (BD) analysis of ONM-501 in mice and safety evaluation in mice, rats and primates. Methods: PC7A polymers conjugated with LiCOR 800CW were mixed with unlabeled PC7A in 1:9 ratio and cGAMP was encapsulated into micelles to generate an “always-on” fluorescently labelled ONM-501-CW800. Naïve or tumor-bearing mice were injected subcutaneously (SC) or intratumorally (IT) with ONM-501-CW800, respectively, and plasma and multiple organ samples were collected; the whole tissue specimens were first imaged ex vivo using LiCOR Pearl Imaging system, and then homogenized and the fluorescence quantified against standard curves prepared by spiking ONM-501-CW800 into a homogenate of the relevant matrix. PK parameters were calculated using non-compartmental methods. Safety and tolerability were evaluated by single- and multiple-dose SC injections in naïve animals up to the highest feasible doses. Results: The BD pattern of ONM-501-CW800 was similar after IT and SC injections. The highest concentrations were observed at the injection sites and draining lymph nodes at all timepoints for both routes of administration. The concentrations in the injection site were much higher in tumors following IT than in dermal tissue following SC injection. After a 50 µg dose, systemic exposure to ONM-501-CW800 was ~1.8- and 2.4-fold lower after IT than SC injection based on Cmax and AUC(inf), respectively. The plasma t½ after IT injection, 17.4 hours, was ~1.3-fold longer than after SC injection, 12.9 hours. The Cmax and AUC (inf) in tumors were ~144- and 120-fold higher than in plasma after IT injection, with a t½ of 25.2 hours in tumors. In single-dose toxicology studies, ONM-501 was well tolerated in mice, rats and monkeys without severe or irreversible systemic toxicities up to the maximum feasible SC doses at 74, 45 and 30 mg/kg, respectively. In the 4-week repeat-dose GLP toxicology studies, the highest non-severely toxic SC dose (HNSTD) was 30 and 7.5 mg/kg in rats and monkeys, respectively. Conclusions: Systemic exposure to ONM-501 was lower after IT than SC administration, which is consistent with increased ONM-501 retention in tumors. Combined with preclinical toxicology studies, ONM-501 showed a favorable pharmacokinetic, tolerability and safety profile that support its continued development in cancer patients. Citation Format: Zirong Chen, Gang Huang, Katy Torres, Fiona Stavros, Alessandra Ahmed, Jason Miller, Tian Zhao, Jinming Gao, Ruolan Han. ONM-501, a dual-activating polyvalent STING agonist, enhances tumor retention and demonstrates favorable preclinical safety profile [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB245.

Safety Surveillance During Drug Development: Comparative Evaluation of Existing Regulations.

Drug safety monitoring is essential for developing efficient and safe treatments. It starts with preclinical toxicology studies and continues with the observation and analysis of potentially harmful effects in humans throughout the whole drug life cycle. Safety surveillance during the clinical phase is of paramount importance for protecting the health of clinical trial (CT) participants at a period when relatively little is known about the drug safety profile, and for reassuring that detected risks are minimized when the product obtains marketing approval. This review aimed to investigate current safety surveillance methods during drug development worldwide, in order to identify potential gaps and opportunities for amelioration. To this end, international guidelines, standards, and local legislations about CTs were reviewed and compared. Our review revealed common strategies, mainly in alignment with international guidelines, especially concerning the systematic collection, assessment, and expedition of adverse events by investigators and sponsors and the preparation of periodic aggregate safety reports by sponsors, as a means to inform health authorities (HAs) about the evolving benefit-risk balance of the investigational product. Inconsistencies in safety surveillance mainly concerned local expedited reporting requirements. Significant gaps were identified in the methodologies for aggregate analyses and the responsibilities of HAs. Addressing the regulatory discrepancies and harmonizing the safety surveillance processes at a global level would increase the usability of safety data accumulated by clinical studies worldwide, thus enabling and hopefully accelerating the development of safe and efficient drug therapies.

Preclinical development of non-viral gene therapy for patients with advanced pancreatic cancer

Pancreatic cancer remains one of the greatest challenges in oncology for which therapeutic intervention is urgently needed. We previously demonstrated that the intra-tumoral gene transfer of somatostatin receptor 2, to combat tumor aggressiveness, or of deoxycytidine kinase and uridylate monophosphate kinase, to sensitize to gemcitabine chemotherapy, has anti-tumoral potential in experimental models of cancer. Here, we describe the development of the CYL-02 non-viral gene therapy product that comprises a DNA-plasmid encoding for the three aforementioned genes, which expression is targeted to tumor cells, and complexed with polyethyleneimine non-viral vector. We performed pre-clinical toxicology, bio-distribution, and therapeutic activity studies of CYL-02 in two rodent models of pancreatic cancer. We found that CYL-02 is safe, does not increase gemcitabine toxicity, is rapidly cleared from blood following intravenous administration, and sequestered in tumors following intra-tumoral injection. CYL-02 drives the expression of therapeutic genes in cancer cells and strongly sensitizes tumor cells to gemcitabine, both invitro and invivo, with significant inhibition of tumor cells dissemination. This study was instrumental for the later use of CYL-02 in patients with advanced pancreatic cancer, demonstrating that rigorous and thorough preclinical investigations are informative for the clinical transfer of gene therapies against this disease.