Efficacious Dose Range Research Articles

Prediction of Cardiac ATTR Depletion by NI006 (ALXN2220) Using Mechanistic PK/PD Modeling.

NI006 (aka ALXN2220) is a therapeutic antibody candidate in phase III clinical development for the depletion of amyloid transthyretin (ATTR) in patients with ATTR cardiomyopathy, an infiltrative cardiomyopathy leading to increased left ventricular wall thickness (LVWT). The mode-of-action consists in removal of disease-causing amyloid accumulations by activating phagocytic immune cells, a mechanism without precedent in cardiology. To select a safe and potentially efficacious dose range and treatment duration for a combined first-in-human and proof-of-concept clinical phase Ib study, we developed a mechanistic pharmacokinetic and pharmacodynamic (PK/PD) model that can predict NI006 exposure, its effects on cardiac amyloid load and on LWVT, which is a predictor of heart failure in this disease. The PK/PD model predictions supported 0.3 mg/kg monthly dosing as a safe starting dose and identified 10-60 mg/kg monthly as the potentially efficacious dose range with substantial and dose dependent cardiac amyloid burden reduction within 4 months for 60 mg/kg and 10 months for 10 mg/kg. These predictions were in good agreement with the observed primary results of the clinical phase Ib study where amyloid burden was measured by imaging. This novel translational PK/PD model provided important predictions to guide the design of the phase Ib study of NI006, indicating the value of this approach to integrate preclinical results into clinical trial design and increase translational success.

First-in-Human Study of the Ataxia Telangiectasia and Rad3-Related (ATR) Inhibitor Tuvusertib (M1774) as Monotherapy in Patients with Solid Tumors.

Tuvusertib (M1774) is a potent, selective, orally administered ataxia telangiectasia and Rad3-related (ATR) protein kinase inhibitor. This first-in-human study (NCT04170153) evaluated safety, tolerability, maximum tolerated dose (MTD), recommended dose for expansion (RDE), pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of tuvusertib monotherapy. Ascending tuvusertib doses were evaluated in 55 patients with metastatic or locally advanced unresectable solid tumors. A safety monitoring committee determined dose escalation based on PK, PD, and safety data guided by a Bayesian 2-parameter logistic regression model. Molecular responses (MR) were assessed in circulating tumor DNA samples. Most common grade ≥3 treatment-emergent adverse events were anemia (36%), neutropenia, and lymphopenia (both 7%). Eleven patients experienced dose-limiting toxicities, most commonly grade 2 (n = 2) or 3 (n = 8) anemia. No persistent effects on blood immune cell populations were observed. The RDE was 180 mg tuvusertib QD (once daily), 2 weeks on/1 week off treatment, which was better tolerated than the MTD (180 mg QD continuously). Tuvusertib median time to peak plasma concentration ranged from 0.5 to 3.5 hours and mean elimination half-life from 1.2 to 5.6 hours. Exposure-related PD analysis suggested maximum target engagement at ≥130 mg tuvusertib QD. Tuvusertib induced frequent MRs in the predicted efficacious dose range; MRs were enriched in patients with radiological disease stabilization, and complete MRs were detected for mutations in ARID1A, ATRX, and DAXX. One patient with platinum- and PARP inhibitor-resistant BRCA wild-type ovarian cancer achieved an unconfirmed RECIST v1.1 partial response. Tuvusertib demonstrated manageable safety and exposure-related target engagement. Further clinical evaluation of tuvusertib is ongoing.

Abstract LB_A25: Updated Phase 1 results from the PYNNACLE Phase 1/2 study of PC14586, a selective p53 reactivator, in patients with advanced solid tumors harboring a TP53 Y220C mutation

Abstract Background: Mutations in the TP53 gene leading to p53 inactivation are the most common mutational event across human cancers. PC14586 is a first-in-class p53 reactivator that selectively binds to the mutated p53 Y220C protein and restores p53 wild-type activity. Preclinical data support potential for activity of PC14586 across TP53 Y220C-bearing tumors, with enhanced activity in KRAS wild-type (WT) models, consistent with the important parallel roles for p53 inactivation and oncogenic KRAS in tumorigenesis. Preliminary analysis of Phase 1 data from the Phase 1/2 PYNNACLE trial (NCT04585750) evaluating PC14586 in patients with advanced TP53 Y220C solid tumors showed that PC14586 was well tolerated with preliminary clinical activity across multiple tumor types in the efficacious dose range (1150 mg QD to 1500 mg BID). This updated Phase 1 analysis assesses PC14586 in patients treated across the efficacious dose range. Methods: Eligible patients (≥12 years) with locally advanced or metastatic solid tumors with a TP53 Y220C mutation received increasing oral doses of PC14586 to evaluate safety, PK, and preliminary efficacy via RECIST v1.1, and to determine the Recommended Phase 2 Dose (RP2D). Tumor molecular profiling was assessed for the impact of KRAS status on response. Results: As of 1 May 2023, 61 patients were treated in the efficacious dose range (safety population): median age 63 (range 32-84) years, 62% female, and median of 3 (range 1–9) prior lines of systemic therapy. The most frequent treatment-related adverse events (TRAEs) (≥10%) were nausea (42.3%), vomiting (35.2%), diarrhea (19.7%), increased creatinine (18.3%), fatigue (14.1%), and increased AST and ALT (12.7% each); 3% of patients discontinued PC14586 due to TRAEs. Most TRAEs were grade 1 or 2; the most common grade 3 TRAEs were anemia (4.2%) and increased ALT (2.8%). PC14586 administered with food led to improvement in nausea and vomiting. Dose proportional and linear PK was observed with a median half-life of 19 hours. Among patients with measurable disease, 36 patients had KRAS WT and 15 patients had KRAS mutated tumors. A total of 12 PRs (ORR 33.3%) were observed (9 confirmed and 3 unconfirmed - pending confirmation) in patients with KRAS WT disease across multiple tumor types including ovarian, breast, prostate, small-cell lung, and endometrial cancer. The median duration of confirmed response was 7 months. In patients with a KRAS mutation, there were no confirmed responses, although clinical activity was observed. At 2000 mg QD, the ORR was 46.2% in patients with TP53 Y220C and KRAS WT tumors (n=13). A RP2D of 2000 mg QD was selected based on overall safety, PK and preliminary efficacy. Conclusions: PC14586 was well-tolerated with a favorable safety profile. Efficacy was achieved in heavily pre-treated patients across multiple tumor types. The PYNNACLE registrational Phase 2 trial will assess PC14586 as monotherapy at the RP2D of 2000 mg QD in patients with TP53 Y220C and KRAS WT advanced solid tumors. Additional/updated data will be presented at the conference. Citation Format: Alison M Schram, Geoffrey I Shapiro, Melissa L Johnson, Anthony W. Tolcher, John A Thompson, Anthony B El-Khoueiry, Andrae L Vandross, Shivaani Kummar, Aparna R Parikh, Dale R Shepard, Ursula Garczarek, Kim LeDuke, Lisa Sheehan, Marc Fellous, Leila Alland, Ecaterina E Dumbrava. Updated Phase 1 results from the PYNNACLE Phase 1/2 study of PC14586, a selective p53 reactivator, in patients with advanced solid tumors harboring a TP53 Y220C mutation [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_A25.

Anti-Leukemic Effects of CK1α Degrader As Monotherapy and in Combination with Targeted Drugs

CK1⍺ is a member of casein kinase 1 (CK1) family, a multifunctional serine/threonine kinase conserved in eukaryotes from yeast to humans. Substrates of CK1⍺ include various proteins important in cancer and regulate multiple survival pathways such as p53, Wnt, autophagy and NF-B signaling pathways. In particular, CK1- serves as an upstream regulator of p53 pathway through regulation of MDM2 and MDMX and degradation of CK1- may prevent MDM2 and/or MDMX mediated inactivation of p53 function, thus facilitate cell death. We identified an early hit compound, distinct from known immunomodulatory imide drugs (IMiDs) such as lenalidomide or thalidomide. In order to identify compounds having distinct characteristic with previously published IMiDs, we designed multiple compounds with a wide range of glue effect based on the binding mode analysis and binding structure of CRBN and known IMiDs. Among them, PinA1 (early lead compound) selectively degraded CK1-, in the nanomolar range with the highest potency. PinA1 induced expression of p53 which led to apoptosis in AML cell lines with wild-type TP53 (MV4-11, MOLM-13, and MOLM-14), but not in TP53 mutated cells (KASUMI-1, and KG-1). Of note, in TP53 wild-type cells, expression of MDM2 and p21 increased as well, which may limit p53-induced apoptosis in these cells. PinA1 also induced CK1- degradation and p53-dependent apoptosis in primary AML cells in vitro. On the other hand, PinA1 had marginal effects on the viability of human peripheral blood mononuclear cells and CD34+ cells, with minimal activation of the p53 pathway at an efficacious dose range for MV4-11 compared to MDM2 inhibitors. PinA1 enhanced apoptosis in combination with FLT3, BCL-2, or MDM2 inhibitors in AML cell lines (MV4-11, MOLM-14) and primary AML cells in vitro. To test the efficacy of PinA1 in vivo, we injected MOLM-14/ luc/GFP or MV4-11/ luc/Thy1.1 into nonirradiated NGS mice. Five or Six days after cell injection, mice were randomized into 4 groups: vehicle, PinA1, and PinA1 plus AMG232 (MDM2 inhibitor), venetoclax, or gilteritinib. Bioluminescence imaging (BLI) demonstrated significantly less leukemia burden in all treated groups than vehicles; leukemia progression was lowest with combination therapy. Flow cytometry with sacrificed mice revealed the lowest leukemia burden in combination therapy, consistent with those from BLI. Western blotting with sorted leukemic cells from bone marrow and spleen revealed CK1- degradation in vivo. PinA1- and other single drug-treated mice had prolonged survival compared with vehicles, and combination therapy extended survival even further. Patient-derived xenograft models from two FLT3-ITD-mutated AML patients also showed potent anti-leukemic effects of PinA1 as monotherapy and in combination with gilteritinib. In conclusion, our study showed that PinA1 selectively degrades CK1α, enhancing expression of p53, which then induces apoptosis in TP53-wild-type AML cells, but not in TP53-mutated AML cells, thereby producing anti-leukemic effects as monotherapy or in combination with targeted therapies. The minimal effect of PinA1 on normal hematopoietic cells may positively contribute to safety in future clinical trials. This novel targeting approach may improve the current targeted therapies in combination once validated.

A Phase 1, First-in-Human, Dose Escalation and Dose-Expansion Study of a BCMAxCD38xCD3 Targeting Trispecific Antibody ISB 2001 in Subjects with Relapsed/Refractory Multiple Myeloma

Background Despite advances, multiple myeloma (MM) remains an incurable disease and resistance mechanisms are emerging. ISB 2001 has been designed to overcome those resistance mechanisms inherent to current MM therapies such as monoclonal antibodies (e.g. daratumumab), BCMA-targeted therapies, proteasome inhibitors(PIs), or immunomodulatory drugs(IMiDs). ISB 2001 is a first in class Trispecific T cell engager (TCE) that redirects cytotoxic T cells to BCMA and/or CD38 expressing myeloma cells. Simultaneous targeting of the two tumor associated antigens (TAA) may increase binding to tumor cells through avidity even with heterogeneous or low expression of the targeted TAA (BCMA or CD38). Therefore, it may overcome tumor escape mechanisms associated with low tumor antigenic expression inherent to current MM targeted therapies. Preclinically, ISB 2001 has demonstrated improved activity when compared to other BCMA or CD38 targeted molecules either alone or in combination across different MM models (M. Pihlgren et al., Blood. 140, 858-859 (2022), M. Pihlgren et al., Cancer Res. 83, 2970-2970 (2023)). Study design and methods This first-in-human, multicenter, open label Phase 1 study is assessing the safety, tolerability, efficacy, pharmacokinetics (PK), and pharmacodynamics (PD) of ISB 2001 in relapsed/refractory multiple myeloma (RRMM) patients. This study will enroll subjects treated with prior IMiDs, PIs, and anti-CD38 therapies, or intolerant of, established therapies known to provide benefit (prior BCMA therapies, or prior transplantation and cellular therapies allowed).be conducted in two parts (Part 1: Dose escalation and Part 2: Dose expansion) (Figure 1). Criteria for enrollment in this study include patients with RRMM with measurable disease who have been treated with an anti-CD38 antibody, IMiDs, PIs either in combination or as a single agent, and /or intolerant of established therapies known to provide clinical benefit. ISB 2001 is being administered weekly by subcutaneous (SC) injection in 28-day cycles, with two step-up doses on cycle 1 day 1 (C1D1) and C1D4 before administering the full dose on C1D8. The first-in-human dose was derived by integrating both in vitro and in vivo preclinical data benchmarked to teclistamab utilizing a quantitative systems pharmacology (QSP) model guided approach. The fractionated step-up dosing before administering the full dose on C1D8 was included in every cohort preemptively to minimize the potential cytokine release syndrome (CRS) risk. The study will follow a rapid titration single patient dose escalation design until the completion of cohort 3 or until one of the safety conversion criteria are met, whichever comes first, after which the design will be converted to a conventional 3+3 dose escalation. The primary outcome measure is the number of DLTs during the first 28 days after the first study treatment (ie, Cycle 1) in each cohort. Once a potential safe and efficacious dose range is identified, the Part 2 expansion will start enrollment in two arms at two putative recommended Part 2 doses with 1:1 randomization with at least 20 patients per arm (FDA Project Optimus). The primary objective of Part 2 is to confirm safety and to select the recommended Phase 2 dose (RP2D). Secondary endpoints include PK parameters, immunogenicity incidence, ORR, CRR and DOR based on IMWG criteria. Exploratory endpoints include levels of cytokines, chemokines, sCD38, sBCMA, APRIL and BAFF in peripheral blood, immunophenotyping in peripheral blood and bone marrow, and MRD negative rate. Approximately 40 patients will be enrolled in Part 1 at sites in Australia, France and the United States. A total of approximately 40 evaluable patients will be enrolled in Part 2. The study is currently open for enrollment (Clinicaltrials.gov identifier: NCT05862012).

Integrated Preclinical Data Analysis of ISB 2001 Enables Optimal Starting Dose Selection for a First-in-Class Trispecific T Cell Engager Phase1 Study in Multiple Myeloma

Despite significant clinical benefit achieved by targeted immunotherapies in recent years, durable responses are still limited in multiple myeloma (MM) 1,2 potentially due to expansion of clones with low target expression 3,4,5. We have previously reported ISB 2001 as a first in class trispecific T cell engager (TCE) targeting BCMA and CD38 with a superior potency to a single Tumor Associated Antigen TCE 6,7. TCEs are often not fully cross reactive with preclinical species for conducting GLP toxicology. For TCEs, a MABEL approach is often used to derive a starting dose 9, generally requiring multiple dose escalations with low probability of patient benefit before an efficacious dose is reached. As ISB 2001 lacks cynomolgus cross reactivity, we could have used a MABEL approach to derive the starting dose. Instead, we generated datasets employing in vitro and in vivo models for ISB 2001 and teclistamab (possessing a similar mode of action). A quantitative systems pharmacology (QSP) model 8 incorporating in vitro and in vivo data was developed and used to predict clinically efficacious doses for both molecules. The QSP model demonstrated that inclusion of in vivo data was key to the best prediction of actual clinical efficacy for teclistamab. Based on this benchmarking, the ISB 2001 efficacious dose range and minimal pharmacologically active dose (MPAD) were derived. Further refinement of the starting dose was performed by introducing step-up dose administration to mitigate the risk of cytokine release syndrome and to reduce the concentration of the first administration of ISB 2001 below the threshold of cytokine release in vitro. This strategy led to the first full dose, which was approximately two-fold lower than the MPAD but 60-fold greater than the MABEL-based starting dose, and therefore significantly reduced patient exposure to sub-therapeutic doses. This approach for the selection of the starting dose for the First-in-Human clinical study was accepted by the U.S. FDA and the Human Research Ethics Committee in Australia. The utility of QSP modelling in the development of trispecific TCEs has been demonstrated before 10,11. However, to our knowledge this is the first time that a starting dose in clinical studies of a trispecific TCE, lacking species cross-reactivity and therefore a GLP toxicology preclinical package, has been derived based on integrated preclinical data analysis utilizing a QSP model. Clinical evaluation of ISB 2001 is ongoing in a phase I dose escalation and dose expansion study in subjects with relapsed/refractory MM (NCT05862012).

Dose Escalation of ISB 1342, a Novel CD38xCD3 Bispecific Antibody, in Patients with Relapsed / Refractory Multiple Myeloma (RRMM)

Introduction: ISB 1342 is a humanized CD38xCD3 bispecific T-cell engager using Ichnos proprietary Bispecific Engagement by Antibodies based on the T cell receptor (BEAT ®) platform, designed to simultaneously bind CD38 on multiple myeloma (MM) cells and CD3ε on T cells, to induce tumor killing. This mechanism of action is different from existing monospecific CD38 targeting therapies and was designed to overcome resistance to daratumumab in MM. ISB 1342 exhibits potent killing of the primary MM cells and MM cell lines with low sensitivity to daratumumab ( Pouleau B. et al. Blood 2023; 142 (3): 260-273). We report here, the updated findings from the weekly dose-escalations of intravenous (IV) and subcutaneous (SC) injections of an ongoing, single-agent phase 1 study (NCT03309111) of ISB 1342 in patients with RRMM. Methods: Adult patients with RRMM that relapsed after or were refractory to prior therapies, including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 antibody; received ISB 1342 on a weekly (QW) schedule by IV or SC injection with a priming dose on the first day in 2 parallel dose-escalation schemas. Patients had measurable disease per the International Myeloma Working Group (IMWG) criteria (2016). Dose escalation in the QW schedule began at 0.2/0.3 mg/kg priming/treatment dose and followed a “3 + 3” design. The primary study objectives are to determine the maximum tolerated dose (MTD) and select a recommended phase 2 dose (RP2D) of ISB 1342. Secondary objectives includ evaluation of anti-myeloma activity, pharmacokinetics (PK), pharmacodynamics, and immunogenicity of ISB 1342. Results: As of July 18, 2023, based on ongoing clinical database, 39 subjects had received weekly IV infusions of ISB 1342 in 8 dose-escalation groups from 0.2/0.3 mg/kg to 4.0/16.0 mg/kg as priming/treatment dose; and 7 additional subjects had received weekly SC injections at 2.0/8.0 mg/kg. Two different formulations have been tested in SC group. Median number of cycles administered was 2. The majority were male (57%) and white (74%); 13% were Black or African American. The median age was 69 years (range, 54-76) and the median time since diagnosis was 6.6 years (range, 2.8-22.2). The median number of prior anti-myeloma lines of therapy was 6 (range 1-12). Twenty-one (67%) subjects were considered to be triple-class refractory and 18 (48%) penta-drug refractory. Forty-one (89%) subjects experienced treatment-related adverse events (TRAEs) of any grade. Most TRAEs were grade 1-2, including infusion related reactions (37%), cytokine release syndrome (CRS, 34%, all grade 1or 2), anemia (24%), neutropenia (24%), and thrombocytopenia (17%). Five subjects in SC group (71% of SC) had injection site reaction, all grade 1 or 2. Grade 3 or higher TRAEs occurring in more than 5% of subjects were infusion related reaction (no grade 4), anemia (no grade 4), neutropenia, leukopenia. No Grade 5 TRAE was observed. After QW IV infusion, ISB 1342 serum concentration peaked at the end of infusion and then showed bi-exponential decline. ISB 1342 serum exposures increased in a dose linear fashion across the tested IV infusion dose range. The limited PK data after SC injection suggest slow presentation of ISB 1342 into the systemic circulation leading to lower C max and delayed T max relative to IV. Transient increases in serum cytokines were observed within 24 hours after ISB 1342 dosing, including IFNg, TNFa, IL-2, IL-6 and IL-10. Transient increases in T-cell activation were observed by flow cytometry at 24-48 hours after ISB 1342 dosing at 1.0 / 4.0 μg/kg and above, based on increased expression of CD69 on peripheral blood CD4+ and CD8+ T-cell populations (Figure 1). Comparison of the available data from subjects treated at 2 / 8 μg/kg (Cohort 109) indicated reduced T-cell activation following SC compared to IV administration of ISB 1342. The efficacy signals observed in Cohorts 108 and 109 are consistent with the estimates of the lower boundary of the predicted efficacious dose range using a quantitative systems pharmacology (QSP) model based on preclinical data. Updated clinical data, including response rates and safety data, will be present at the meeting. Conclusions: Treatment with ISB 1342 was well tolerated at higher dose levels evaluated. Observed CRS events were moderate. No increased risk of infection has been observed . Updated safety, efficacy, biomarker and PK data will be presented.

Abstract 4950: Discovery of potent and selective CK1α molecular degrader with a favorable safety profile for acute myeloid leukemia and solid tumors

Abstract CK1α, an isoform of casein kinase 1 (CK1), promotes tumor growth by enhancing negative effects of MDM2 and MDMX on p53. Unlike other cancer types, the frequency of TP53 mutations is relatively low (< 20%) in acute myeloid leukemia (AML). Therefore, promoting apoptosis by activation of p53 pathway has been a promising strategy for treatment of AML with wild-type (WT) TP53. However, preclinical activities of p53 activators have not been fully translated into clinic, partly due to their on-target hematological toxicities. We hypothesized that inhibition of CK1α can be an alternative strategy. To develop a small molecule targeting CK1α, we identified a novel CK1α-selective molecular glue degrader (MGD), PIN-A1 through screening of compounds hijacking cereblon (CRBN) E3 ligase. Here, we report its robust pharmacological activities in various preclinical AML models as a single agent or in combination with other targeted therapies along with its superior safety profile to MDM2 inhibitors. First, we demonstrated PIN-A1 can form a ternary complex with CK1α and CRBN using TR-FRET assay. Selective degradation of CK1α by PIN-A1 was also confirmed by global proteomics analysis. PIN-A1 induced rapid degradation of CK1α in human AML MV-4-11 cells harboring WT TP53, followed by increasing the level of p53 protein and its downstream target genes, ultimately leading to apoptotic cell death. Consistent with these results, preferential sensitivity of AML cells with WT TP53 to the CK1α degrader was demonstrated in screening assay of broad panel of liquid cancer cell lines. When combined with other targeted therapies agents used for AML, PIN-A1 displayed strong synergistic effects in cell killing. To evaluate its pharmacological activity in vivo, PIN-A1 was tested in a xenograft model engrafted with MV-4-11 and a dissemination model of MOLM-14, respectively. Systemic administration of PIN-A1 alone resulted in robust antitumor activity consistent with > 90% CK1α degradation in tumor tissues, comparably achieved at a much lower dose in combo treatments. Importantly, animals remained tumor-free (5/8) in the MV-4-11 model or prolonged survival in the disseminated model even after they were no longer on the combination treatment of PIN-A1 with a targeted agent X. Lastly, while PIN-A1 had negligible effects on the viability of human PBMC with minimal activation of the p53 pathway at an efficacious dose range for MV-4-11 (Therapeutic index= 8,333), agent X induced p53 pathway and enhanced anti-leukemic activity to a similar extent in two cell types (Therapeutic index=4). Also, we found that the combination treatment of PIN-A1 with agent X had a substantial effect on several solid tumors driven by enhancing the stability and activity of p53. In summary, these results suggest that a CK1α MGD with its favorable safety profile has a potential to become an effective treatment option for advanced AML and solid tumors. Citation Format: Jinuk Kong, Jisu Park, Heekyu Lee, Hyunseok Kang, Deokjae Lee, Hyunsun Jo. Discovery of potent and selective CK1α molecular degrader with a favorable safety profile for acute myeloid leukemia and solid tumors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4950.

Leveraging in vitro and pharmacokinetic models to support bench to bedside investigation of XTMAB-16 as a novel pulmonary sarcoidosis treatment.

Background: Sarcoidosis is a chronic, multisystem inflammatory disorder characterized by non-caseating epithelioid granulomas; infiltration of mononuclear cells; and destruction of microarchitecture in the skin, eye, heart, and central nervous system, and the lung in >90% of cases. XTMAB-16 is a chimeric anti-tumor necrosis factor alpha (TNFα) antibody, distinct from other anti-TNF antibodies based on its molecular structure. The efficacy of XTMAB-16 has not been clinically demonstrated, and it is still undergoing clinical development as a potential treatment for sarcoidosis. The current study demonstrates the activity of XTMAB-16 in a well-established in vitro sarcoidosis granuloma model, although XTMAB-16 is not yet approved by the United States Food and Drug Administration (FDA) for treatment of sarcoidosis, or any other disease. Objective: To provide data to guide safe and efficacious dose selection for the ongoing clinical development of XTMAB-16 as a potential treatment for sarcoidosis. Methods: First, XTMAB-16 activity was evaluated in an established in vitro model of granuloma formation using peripheral blood mononuclear cells from patients with active pulmonary sarcoidosis to determine a potentially efficacious dose range. Second, data obtained from the first-in-human study of XTMAB-16 (NCT04971395) were used to develop a population pharmacokinetic (PPK) model to characterize the pharmacokinetics (PK) of XTMAB-16. Model simulations were performed to evaluate the sources of PK variability and to predict interstitial lung exposure based on concentrations in the in vitro granuloma model. Results: XTMAB-16 dose levels of 2 and 4mg/kg, once every 2weeks (Q2W) or once every 4 weeks (Q4W) for up to 12weeks, were supported by data from the non-clinical, in vitro secondary pharmacology; the Phase 1 clinical study; and the PPK model developed to guide dose level and frequency assumptions. XTMAB-16 inhibited granuloma formation and suppressed interleukin-1β (IL-1β) secretion in the in vitro granuloma model with a half maximal inhibitory concentration (IC50) of 5.2 and 3.5μg/mL, respectively. Interstitial lung concentrations on average, following 2 or 4mg/kg administered Q2W or Q4W, are anticipated to exceed the in vitro IC50 concentrations. Conclusion: The data presented in this report provide a rationale for dose selection and support the continued clinical development of XTMAB-16 for patients with pulmonary sarcoidosis.

Translational PK/PD Modeling of Tumor Growth Inhibition and Target Inhibition to Support Dose Range Selection of the LMP7 Inhibitor M3258 in Relapsed/Refractory Multiple Myeloma.

M3258 is an orally bioavailable, potent, selective, reversible inhibitor of the large multifunctional peptidase 7 (LMP7, β5i, PSMB8) proteolytic subunit of the immunoproteasome, a component of the cellular protein degradation machinery, highly expressed in malignant hematopoietic cells including multiple myeloma. Here we describe the fit-for-purpose pharmacokinetic (PK)/pharmacodynamic (PD)/efficacy modeling of M3258 based on preclinical data from several species. The inhibition of LMP7 activity (PD) and tumor growth (efficacy) were tested in human multiple myeloma xenografts in mice. PK and efficacy data were correlated yielding a free M3258 concentration of 45 nM for half-maximal tumor growth inhibition (KC50). As M3258 only weakly inhibits LMP7 in mouse cells, both in vitro and in vivo bridging studies were performed in rats, monkeys, and dogs for translational modeling. These data indicated that the PD response in human xenograft models was closely reflected in dog PBMCs. A PK/PD model was established, predicting a free IC50 value of 9 nM for M3258 in dogs in vivo, in close agreement with in vitro measurements. In parallel, the human PK parameters of M3258 were predicted by various approaches including in vitro extrapolation and allometric scaling. Using PK/PD/efficacy simulations, the efficacious dose range and corresponding PD response in human were predicted. Taken together, these efforts supported the design of a phase Ia study of M3258 in multiple myeloma patients (NCT04075721). At the lowest tested dose level, the predicted exposure matched well with the observed exposure while the duration of LMP7 inhibition was underpredicted by the model. SIGNIFICANCE STATEMENT: M3258 is a novel inhibitor of the immunoproteasome subunit LMP7. The human PK and human efficacious dose range of M3258 were predicted using in vitro-in vivo extrapolation and allometric scaling methods together with a fit-for-purpose PK/PD and efficacy model based on data from several species. A comparison with data from the Phase Ia clinical study showed that the human PK was accurately predicted, while the extent and duration of PD response were more pronounced than estimated.

Nonhuman Primates Are Protected against Marburg Virus Disease by Vaccination with a Vesicular Stomatitis Virus Vector-Based Vaccine Prepared under Conditions to Allow Advancement to Human Clinical Trials.

Vaccines are needed to disrupt or prevent continued outbreaks of filoviruses in humans across Western and Central Africa, including outbreaks of Marburg virus (MARV). As part of a filovirus vaccine product development plan, it is important to investigate dose response early in preclinical development to identify the dose range that may be optimal for safety, immunogenicity, and efficacy, and perhaps demonstrate that using lower doses is feasible, which will improve product access. To determine the efficacious dose range for a manufacturing-ready live recombinant vesicular stomatitis virus vaccine vector (rVSV∆G-MARV-GP) encoding the MARV glycoprotein (GP), a dose-range study was conducted in cynomolgus macaques. Results showed that a single intramuscular injection with as little as 200 plaque-forming units (PFUs) was 100% efficacious against lethality and prevented development of viremia and clinical pathologies associated with MARV Angola infection. Across the vaccine doses tested, there was nearly a 2000-fold range of anti-MARV glycoprotein (GP) serum IgG titers with seroconversion detectable even at the lowest doses. Virus-neutralizing serum antibodies also were detected in animals vaccinated with the higher vaccine doses indicating that vaccination induced functional antibodies, but that the assay was a less sensitive indicator of seroconversion. Collectively, the data indicates that a relatively wide range of anti-GP serum IgG titers are observed in animals that are protected from disease implying that seroconversion is positively associated with efficacy, but that more extensive immunologic analyses on samples collected from our study as well as future preclinical studies will be valuable in identifying additional immune responses correlated with protection that can serve as markers to monitor in human trials needed to generate data that can support vaccine licensure in the future.

Abstract 2903: ISB 1442, a first-in-class CD38 and CD47 bispecific antibody innate cell modulator for the treatment of CD38+ malignancies

Abstract ISB 1442 is a fully human bispecific antibody (BsAb) using BEAT (Bispecific Engagement by Antibodies based on the T-cell receptor) platform to target CD38 and CD47 as treatment for CD38+ malignancies, including multiple myeloma (MM). ISB 1442 is designed with a bi-paratopic anti-CD38 arm that strongly binds to CD38+ tumor cells and an anti-CD47 arm made of a single Fab designed to block interaction between CD47 and the signal-regulatory protein alpha (SIRPα) with low affinity. This approach is expected to induce minimal unintended effects on red blood cells (RBC) compared to anti-CD47 monoclonal antibody (mAb) magrolimab as it enables the CD47 binding only upon avidity induced CD38 crosslinking. The Fc portion of ISB 1442 is engineered to enhance antibody dependent cell phagocytosis (ADCP), antibody dependent cell cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC). In vitro, ISB 1442 exhibited higher killing potency compared to daratumumab across a range of CD38-expressing tumor cells. Additionally, ISB 1442 showed in vitro tumor killing potency through phagocytosis comparable to magrolimab, acting mostly through ADCP. To assess the complex mechanisms of action of ISB 1442 in a single system, a multiple mode of action of killing (MMoAK) assay was established to allow for simultaneous killing by natural killer cells, autologous macrophages, as well as complement from human serum. In the MMoAK assay, ISB 1442 exhibited tumor cell killing that was twice as high as daratumumab. In vivo, in a therapeutic model of subcutaneously established Raji tumor xenograft in CB17/SCID mice, ISB 1442 induced higher tumor growth inhibition than daratumumab and comparable tumor regression to magrolimab. On-target specificity was evaluated in vitro in human and monkey whole blood assays. ISB 1442 did not cause any detectable hemolysis, RBC depletion or platelet aggregation and showed markedly lower RBC hemagglutination relative to magrolimab, suggesting a more favorable on-target specificity profile in humans. On the contrary, due to the higher expression of CD38 in monkey RBC compared to human, ISB 1442 showed more pronounced binding on RBC than magrolimab, suggesting that monkey is a more sensitive species than human for toxicological evaluation of CD38-targeted therapies. Finally, by integrating in vitro pharmacology data along with available clinical information on benchmark antibodies, a quantitative systems pharmacology model was developed to simulate potential efficacious dose range in MM. In summary, we report a novel approach for the treatment for CD38+ cancers by co-targeting CD38 and CD47. Based on its unique design and multiple mechanisms of action, ISB 1442 is anticipated to enhance antitumor activity by overcoming known primary and acquired tumor escape mechanisms of resistance relative to daratumumab. Citation Format: Stefano Sammicheli, Camille Grandclement, Elie Dheilly, Maria Panagopoulou, Evangelia Martini, Perrine Suere, Blandine Pouleau, Carole Estoppey, Julia Frei, Jeremy Loyau, Thierry Monney, Adam Drake, Alain Rubod, Marie Agnes Doucey, Vinu Menon, Venkatesha Udupa, Sunitha GN, Daniel Rasmussen, Jeppe Koch Olsen, Roberto Gionannini, Girish Gudi, Ankita Srivastava, Cyril Konto, Mario Perro. ISB 1442, a first-in-class CD38 and CD47 bispecific antibody innate cell modulator for the treatment of CD38+ malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2903.

Elranatamab (PF-06863135), a B-Cell Maturation Antigen (BCMA) Targeted CD3-Engaging Bispecific Molecule, for Patients with Relapsed or Refractory Multiple Myeloma: Results from Magnetismm-1

Elranatamab (PF-06863135), a B-Cell Maturation Antigen (BCMA) Targeted CD3-Engaging Bispecific Molecule, for Patients with Relapsed or Refractory Multiple Myeloma: Results from Magnetismm-1

EFFICACY AND SAFETY OF ELRANATAMAB (PF-06863135), A B-CELL MATURATION ANTIGEN (BCMA)-CD3 BISPECIFIC ANTIBODY, IN PATIENTS WITH RELAPSED OR REFRACTORY MULTIPLE MYELOMA

Elranatamab (PF-06863135) is a humanized bispecific monoclonal antibody (IgG2a) that targets BCMA, a member of the tumor necrosis factor receptor superfamily expressed in multiple myeloma, and CD3 on T cells. We reported results for intravenous (IV) dosing (Raje et al. Blood. 2019;134(S1):1869) and now update for subcutaneous (SC) dosing from the ongoing Phase 1 study (MagnetisMM-1; NCT03269136). Patients received elranatamab at 80, 130, 215, 360, 600, and 1000 μg/kg SC weekly. A modified toxicity probability interval method was used for escalation, with monitoring for dose-limiting toxicity (DLT) to end of the first cycle. Treatment-emergent adverse events (TEAEs) were graded by Common Terminology Criteria for Adverse Events (v4.03), and cytokine release syndrome (CRS) by American Society for Transplantation and Cellular Therapy criteria (Lee et al. Biol Blood Marrow Transplant. 2019;25:625). Response was assessed by International Myeloma Working Group criteria. Pharmacokinetics, cytokine profiling, and T cell immunophenotyping were performed. 30 patients had received elranatamab as of 4-Feb-2021 at 80 (n = 6), 130 (n = 4), 215 (n = 4), 360 (n = 4), 600 (n = 6), or 1000 (n = 6) μg/kg SC weekly. Patients had a median of 8 prior treatments; 87% had triple refractory disease, 97% had prior anti-CD38 therapy, and 23% (7 patients) had prior BCMA-directed antibody drug conjugate (6 of 7 patients) or chimeric antigen receptor T cell therapy (3 of 7 patients). The most common all causality TEAEs included lymphopenia (n = 25, 83%; 20% G3, 63% G4), CRS (n = 22, 73%; 57% G1, 17% G2, none ≥G3), anemia (n = 18, 60%; 50% G3, 0% G4), thrombocytopenia (n = 16, 53%; 17% G3, 20% G4), neutropenia (n = 16, 53%; 23% G3, 30% G4), and injection site reaction (n = 15, 50%; 43% G1, 7% G2, none ≥G3). Both CRS and immune effector cell-associated neurotoxicity syndrome (n = 6, 20%) were limited to ≤G2 with median durations of 3 and 2.5 days, respectively. No DLT was observed. Exposure increased with dose, and T max ranged from 3–7 days. Cytokine increases occurred with the first dose, and increased T-cell proliferation was observed in peripheral blood. The overall response rate (ORR) for doses ≥215 μg/kg was 70% (n = 14/20) including partial response (PR; n = 1), very good PR (VGPR; n = 7), complete response (CR; n = 1), and stringent CR (sCR; n = 5). Median time to response was 22 days, and 3 of 4 patients (75%) with prior BCMA-directed therapy achieved response (VGPR, n = 2 and sCR, n = 1). Updated data, including duration of response, will be presented. Elranatamab demonstrated a manageable safety profile and, across the efficacious dose range (≥215 μg/kg), achieved ORR of 70% with CR/sCR rate of 30%, including responses after prior BCMA-directed therapy. These results demonstrate the safety and efficacy of elranatamab in this relapsed/refractory population and support ongoing development of elranatamab for patients with multiple myeloma, both as monotherapy and in combination with standard or novel therapies.

Phase 1 and 2 Safety, Tolerability and Pharmacokinetics of Single and Multiple Dose Rimegepant as Compared to the Predicted Clinically Efficacious Dose Range (2145)

Phase 1 and 2 Safety, Tolerability and Pharmacokinetics of Single and Multiple Dose Rimegepant as Compared to the Predicted Clinically Efficacious Dose Range (2145)

Efficacy and safety of eslicarbazepine acetate as adjunctive therapy for refractory focal-onset seizures in children: A double-blind, randomized, placebo-controlled, parallel-group, multicenter, phase-III clinical trial

PurposeThis was a phase-III, randomized, double-blind, placebo-controlled study aimed to evaluate efficacy and tolerability of eslicarbazepine acetate (ESL) as adjunctive therapy in pediatric patients with refractory focal-onset seizures (FOS). MethodsChildren (2–18 years old) with FOS, receiving 1–2 antiepileptic drugs, were randomized to ESL or placebo. Treatment was started at 10 mg/kg/day, up-titrated up to 20–30 mg/kg/day, and maintained for 12 weeks, followed by one-year open-label follow-up. Primary efficacy endpoints were relative reduction in standardized seizure frequency (SSF) and proportion of responders (≥50% SSF reduction) from baseline. Safety was evaluated by the incidence of treatment-emergent adverse events (TEAEs). ResultsThe intention-to-treat (ITT) set included 134 patients randomized to ESL and 129 to placebo; 89.6% and 91.5%, respectively, completed the trial. An unbalanced number of seizures at baseline were observed between groups. Least square (LS) mean relative change in SSF from baseline was higher in the ESL group (−18.1%) than in placebo (−8.6%). Proportion of responders between ESL and placebo groups was not statistically different. A post hoc analysis showed greater relative reduction in SSF in patients above 6 years old treated with ESL 20 or 30 mg/kg/day compared with placebo; this was significant in patients above 6 years old treated with ESL 30 mg/kg/day (LS mean difference: 31.9%; p = 0.0478). The observed safety profile in children was consistent with that established in adult studies. ConclusionsAdjunctive ESL treatment was well-tolerated, but this trial failed to demonstrate that ESL was more effective than placebo in the predefined efficacy endpoints; factors that may have contributed to this outcome, affecting particularly the young age group, include etiological heterogeneity, difficulty in recognizing simple partial seizures, high seizure frequency with risk of imbalance, and underestimation of the efficacious dose range.

Abstract CT019: Population pharmacokinetics of an aurora kinase A inhibitor, LY3295668 erbumine (AK-01), in patients with locally advanced or metastatic solid tumors

Abstract Background: The aurora kinase family plays a vital regulatory role in mitotic and meiotic events, with aurora kinase A (AurA) critical to centrosome maturation, mitotic spindle formation and checkpoint activation. LY3295668 erbumine (AK-01) is an inhibitor of AurA with 1000-fold selectivity for inhibition of AurA over aurora kinase B (AurB). Pharmacokinetic-pharmacodynamic (PK-PD) nonclinical models have shown that 90% inhibition of AurA phosphorylation (pAurA) over an extended period (≥ 16 hours per day) was required to yield efficacy in H446 (small cell lung cancer) xenograft models. Nonclinical plasma LY3295668 concentrations associated with 90% pAurA inhibition (IC90) were estimated previously using a direct sigmoidal relationship between PK and pAurA. In this first-in-man study, PK of LY3295668 in patients with advanced/metastatic cancer were evaluated. Human PK profiles were simulated subsequently and compared to pAurA IC90 to estimate a human efficacious dose range. Methods: LY3295668 erbumine was administered to 13 patients with locally advanced or metastatic solid tumors over a dose range of 25 to 75 mg given twice daily (BID). In the first cycle, serial plasma PK samples were collected up to 8 hours on Day 1 and Day 15. Additional trough samples were obtained prior to dosing on Day 2, on Day 8 and at discontinuation if applicable. PK parameter estimations were performed using non-linear mixed effects models in NONMEM v7.3. Results: The population PK model was developed using 146 plasma concentrations collected from 13 patients. A 2-compartment PK model with first order absorption best described the disposition of LY3295668. Following oral administration, LY3295668 was rapidly absorbed with peak concentrations occurring within 1 to 2 hours. The estimated elimination half-life was approximately 21 hours; therefore, steady state was attained within 4 to 5 days of dosing. Simulations of plasma concentration-time profiles showed that at the maximum tolerated dose (MTD) of 25 mg BID, 90% of patients are expected to achieve steady-state plasma concentrations greater than the pAurA IC90 for the entire day. Patients with dose limiting toxicities (DLTs) had the highest model-predicted exposures amongst the 13 patients. Conclusion: At the MTD of 25 mg BID, steady state LY3295668 plasma concentrations are maintained above the pAurA IC90 for the entire dosing interval, exceeding the minimum requirements for efficacy associated with non-clinical xenograft models. Trial Registration: NCT03092934 Citation Format: Eunice Yuen, Yu-Hua Hui, Amparo de la Peña, Sonya C. Tate, John R. Stille, Andrew Lithio, Patricia S. Smith, Quincy Chu, Gerald Batist, Nathaniel Bouganim, Caroline Fortier, Sara Zaknoen, Jill Kremer. Population pharmacokinetics of an aurora kinase A inhibitor, LY3295668 erbumine (AK-01), in patients with locally advanced or metastatic solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT019.

Population Pharmacokinetic/ Pharmacodynamic Modelling of Auditory-Evoked Event-Related Potentials with Lorazepam.

Event-related potentials (ERPs) are commonly used in Neuroscience research, particularly the P3 waveform because it is associated with cognitive brain functions and is easily elicited by auditory or sensory inputs. ERPs are affected by drugs such as lorazepam, which increase the latency and decrease the amplitude of the P3 wave. In this study, auditory-evoked ERPs were generated in 13 older healthy volunteers using an oddball tone paradigm, after administration of single 0.5 and 2 mg doses of lorazepam. Population pharmacokinetics (PK)/pharmacodynamics (PD) models were developed using nonlinear mixed-effects methods in order to assess the effect of lorazepam on the latency and amplitude of the P3 waveforms. The PK/PD models showed that doses of 0.3 mg of lorazepam achieved approximately half of the maximum effect on the latency of the P3 waveform. For P3 amplitude, half the maximum effect was achieved with a dose of 1.2 mg of lorazepam. The PK/PD models also predicted an efficacious dose range of lorazepam, which was close to the recommended therapeutic range. The use of longitudinal P3 latency data allowed better predictions of the lorazepam efficacious dose range than P3 amplitude or aggregate exposure-response data, suggesting that latency could be a more sensitive parameter for drugs with similar mechanisms of action as lorazepam and that time course rather than single time-point ERP data should be collected. Overall, the results suggest that P3 ERP waveforms could be used as potential non-specific biomarkers for functional target engagement for drugs with brain activity, and PK/PD models can aid trial design and choice of doses for development of new drugs with ERP activity.

Aripiprazole Lauroxil: Pharmacokinetic Profile of This Long-Acting Injectable Antipsychotic in Persons With Schizophrenia.

BackgroundAripiprazole lauroxil is an extended-release prodrug of aripiprazole for intramuscular injection, approved for schizophrenia treatment. We developed a population pharmacokinetic (PopPK) model to characterize aripiprazole lauroxil PK and evaluate dosing scenarios likely to be encountered in clinical practice.MethodsData from 616 patients with schizophrenia, collected from 5 clinical studies, were used to construct the PopPK model. The model was subsequently used to evaluate various dose levels and frequency and the impact of dosing delay on aripiprazole concentrations.FindingsThe results of the model indicate that aripiprazole is released into the systemic circulation after 5 to 6 days, and release continues for an additional 36 days. The slow increase in aripiprazole concentration after injection necessitates the coadministration of oral aripiprazole for 21 days with the first injection. Based on the PopPK model simulations, a dosing interval of 882 mg every 6 weeks results in aripiprazole concentrations that fall within the concentration range associated with the efficacious aripiprazole lauroxil dose range (441–882 mg dosed monthly). A 662-mg monthly dose also resulted in aripiprazole concentrations within the efficacious dose range. Aripiprazole lauroxil administration results in prolonged exposure, such that dose delays of 2 to 4 weeks, depending on the dose regimen, do not require oral aripiprazole supplementation upon resumption of dosing.ConclusionsThis PopPK model and model-based simulations were effective means for evaluating aripiprazole lauroxil dosing regimens and management of missed doses. Such analyses play an important role in determining the use of this long-acting antipsychotic in clinical practice.

CBLB502 administration protects gut mucosal tissue in ulcerative colitis by inhibiting inflammation.

Ulcerative colitis (UC) is a nonspecific inflammatory disease for which medications and therapeutic strategies have only been moderately successful. CBLB502, a toll-like receptor 5 (TLR5) agonist derived from Salmonella flagellin, exhibits anticancer and radioprotective activities via modulation of TLRs and the nuclear factor kappa B (NF-κB) signaling pathway and can protect against acute renal ischemic failure. In this study, we intend to examine the effects of CBLB502 on both TLR responses and the interleukin (IL) and NF-κB signaling pathways in UC treatment. The UC mouse model was prepared in BALB/c mice by administering 2,4,6-trinitrobenzene sulfonic acid (TNBS). CBLB502 was used as the therapeutic drug. After CBLB502 therapy, the IL and tumor necrosis factor-α (TNF-α) levels were measured by ELISA. Total RNA and protein of colon samples was extracted. We found that CBLB502 had a distinctive therapeutic effect in the UC model. In control group animals, IL-10 expression in serum was 91.48±24.38 ng/mL; this was higher than in the model group (59.36±14.46 ng/mL, P<0.05) or the treatment group (54.29±5.83 ng/mL, P<0.05). In model group animals, the concentration of TNF-α in serum was 140.11±12.70 ng/mL, which was lower than protein levels in the control group (173.86±29.26 ng/mL, P<0.05). The mRNA levels of TLR1, 2, 3, 4, 6, 7, 8, and 9 in the CBLB502 treatment group were significantly lower than in the model group (P<0.05). Western blot revealed that CBLB502 also reduced NF-κB expression in the mouse colon, but that NF-κB expression was not significantly lower than the model group. CBLB502 can reduce mucosal damage induced by TNBS and inhibit inflammation and TLR expression. The inhibition of UC by CBLB502 is strictly TLR-IL-dependent and is dose-dependent within the efficacious dose range. Therefore, our results suggested that CBLB502 might be a candidate drug for the treatment of UC.