Patritumab deruxtecan in HER2-negative breast cancer: part B results of the window-of-opportunity SOLTI-1805 TOT-HER3 trial and biological determinants of early response.

Patritumab deruxtecan (HER3-DXd) exhibits promising efficacy in breast cancer, with its activity not directly correlated to baseline ERBB3/HER3 levels. This research investigates the genetic factors affecting HER3-DXd's response in women with early-stage hormone receptor-positive and HER2-negative (HR+/HER2-) breast cancer. In the SOLTI-1805 TOT-HER3 trial, a single HER3-DXd dose was administered to 98 patients across two parts: 78 patients received 6.4 mg/kg (Part A), and 44 received a lower 5.6 mg/kg dose (Part B). The CelTIL score, measuring tumor cellularity and infiltrating lymphocytes from baseline to day 21, was used to assess drug activity. Part A demonstrated increased CelTIL score after one dose of HER3-DXd. Here we report CelTIL score and safety for Part B. In addition, the exploratory analyses of part A involve a comprehensive study of gene expression, somatic mutations, copy-number segments, and DNA-based subtypes, while Part B focuses on validating gene expression. RNA analyses show significant correlations between CelTIL responses, high proliferation genes (e.g., CCNE1, MKI67), and low expression of luminal genes (e.g., NAT1, SLC39A6). DNA findings indicate that CelTIL response is significantly associated with TP53 mutations, proliferation, non-luminal signatures, and a distinct DNA-based subtype (DNADX cluster-3). Critically, low HER2DX ERBB2 mRNA, correlates with increased HER3-DXd activity, which is validated through in vivo patient-derived xenograft  models. This study proposes chemosensitivity determinants, DNA-based subtype classification, and low ERBB2 expression as potential markers for HER3-DXd activity in HER2-negative breast cancer.

HER2 quantitative continuous scoring for accurate patient selection in HER2 negative trastuzumab deruxtecan treated breast cancer.

Many targeted cancer therapies rely on biomarkers assessed by scoring of immunohistochemically (IHC)-stained tissue, which is subjective, semiquantitative, and does not account for expression heterogeneity. We describe an image analysis-based method for quantitative continuous scoring (QCS) of digital whole-slide images acquired from baseline human epidermal growth factor receptor 2 (HER2) IHC-stained breast cancer tissue. Candidate signatures for patient stratification using QCS of HER2 expression on subcellular compartments were identified, addressing the spatial distribution of tumor cells and tumor-infiltrating lymphocytes. Using data from trastuzumab deruxtecan-treated patients with HER2-positive and HER2-negative breast cancer from a phase 1 study (NCT02564900; DS8201-A-J101; N = 151), QCS-based patient stratification showed longer progression-free survival (14.8 vs 8.6 months) with higher prevalence of patient selection (76.4 vs 56.9%) and a better cross-validated log-rank p value (0.026 vs 0.26) than manual scoring based on the American Society of Clinical Oncology / College of American Pathologists guidelines. QCS-based features enriched the HER2-negative subgroup by correctly predicting 20 of 26 responders.

Trastuzumab deruxtecan in HER2-positive advanced gastric cancer: exploratory biomarker analysis of the randomized, phase 2 DESTINY-Gastric01 trial.

Trastuzumab deruxtecan (T-DXd) showed statistically significant clinical improvement in patients with human epidermal growth factor receptor 2-positive (HER2+) gastric cancer in the DESTINY-Gastric01 trial. Exploratory results from DESTINY-Gastric01 suggested a potential benefit in patients with HER2-low gastric cancer. Spatial and temporal heterogeneity in HER2 expression or gene alteration, an inherent characteristic of gastric cancer tumors, presents a challenge in identifying patients who may respond to T-DXd. Specific biomarkers related to therapeutic response have not been explored extensively. Exploratory analyses were conducted to assess baseline HER2-associated biomarkers in circulating tumor DNA and tissue samples, and to investigate mechanisms of resistance to T-DXd. Baseline HER2-associated biomarkers were correlated with objective response rate (ORR) in the primary cohort of patients with HER2+ gastric cancer. The primary cohort had 64% concordance between HER2 positivity and HER2 (ERBB2) plasma gene amplification. Other key driver gene amplifications, specifically MET, EGFR and FGFR2, in circulating tumor DNA were associated with numerically lower ORR. Among 12 patients with HER2 gain-of-function mutations, ORR was 58.3% (7 of 12). ORR was consistent regardless of timing of immunohistochemistry sample collection. Further investigations are required in larger studies.

Brain translocator protein occupancy by ONO-2952 in healthy adults: A Phase 1 PET study using [11 C]PBR28.

ONO-2952, a novel antagonist of translocator protein 18 kDa (TSPO), binds with high affinity to TSPO in rat brain and human tumor cell line membrane preparations. This study used the TSPO-specific PET radioligand [11 C]PBR28 to confirm binding of ONO-2952 to brain TSPO in human subjects, and evaluate brain TSPO occupancy and its relationship with ONO-2952 plasma concentration. Sixteen healthy subjects received a single oral dose of 200, 60, 20, or 6 mg ONO-2952 (n = 4 per dose). Two PET scans with [11 C]PBR28 were conducted ≤7 days apart: at baseline and 24 h after ONO-2952 administration. [11 C]PBR28 regional distribution volume (VT ) was derived with kinetic modeling using the arterial input function and a two tissue compartment model. Nonspecific binding (VND ) was obtained on an individual basis for each subject using linear regression as the x-intercept of the Lassen plot. The binding potential relative to VND (BPND ) was derived as the difference between VT in the ROI (VT ROI) and VND , normalized to VND ; BPND = (VT ROI - VND )/VND . TSPO occupancy was calculated as the change in BPND (ΔBPND ) from individual's baseline scan to the on-medication scan to the baseline BPND value. TSPO occupancy by ONO-2952 was dose dependent between 20-200 mg, approaching saturation at 200 mg both in the whole brain and in 15 anatomic regions of interest (ROI). Estimated Ki values ranged from 24.1 to 72.2 nM. This open-label, single-center, single-dose study demonstrated engagement of ONO-2952 to brain TSPO. The relationship between pharmacokinetics and TSPO occupancy observed in this study support the hypothesis that ONO-2952 could potentially modulate neurosteroid production by binding to brain TSPO.

First Clinical Experience with ONO-4232: A Randomized, Double-blind, Placebo-controlled Healthy Volunteer Study of a Novel Lusitropic Agent for Acutely Decompensated Heart Failure.

PURPOSE: The aim of this study was to evaluate the safety, tolerability, and pharmacokinetic parameters of up to 15 dose levels of ONO-4232, a selective agonist for the EP4 subtype of the prostaglandin E2 receptor, with a dual left ventricular lusitropic and venodilatory action, in healthy, adult, male and female volunteers. METHODS: In this randomized, single-center, double-blind, placebo-controlled, single-dose, sequential-group escalation, first in human study, ONO-4232 (0.001, 0.003, 0.01, 0.02, 0.04, 0.08, 0.12, 0.15, 0.18, or 0.27 ng/kg/min) or placebo was administered as a continuous intravenous infusion over 3 hours. Safety, tolerability, and pharmacokinetic data were collected during dosing and over a period of 3 days (Day -1 to Day 2), and at the follow-up visit (Day 7 [±2 days]). FINDINGS: Fifty-seven subjects received ONO-4232 and 19 subjects received placebo. Ten of the planned 15 cohorts (dose range, 0.001-0.27 ng/kg/min) were conducted. A total of 34 treatment-emergent adverse events (TEAEs) were reported in 23 subjects. Overall, the majority of TEAEs were mild. No serious TEAEs or deaths were reported and no subjects discontinued due to adverse events. The most frequently reported TEAE was infusion site erythema. A decrease in systolic blood pressure from baseline occurred for ONO-4232 subjects compared with placebo that was statistically significant for the 0.08 ng/kg/min dose, and a dose-dependent increase in heart rate starting at 0.04 ng/kg/min and achieving statistical significance compared with placebo at 0.15 ng/kg/min and above. More orthostatic events occurred in the higher-dose groups and the dose escalation was terminated due to increasing occurrences of orthostatic hypotension/intolerance. Plasma concentrations of ONO-4232 reached steady state approximately 2 hours after the start of infusion and then declined rapidly after the end of infusion, and systemic exposure appeared to increase in a dose-proportional manner. Approximately 30% of the administered dose of ONO-4232 was excreted in the urine. IMPLICATIONS: In healthy adults ONO-4232 was generally well tolerated in the dose range of 0.001 to 0.27 ng/kg/min. There were dose-related changes in systolic blood pressure and heart rate. Infusion site erythema, which was likely associated with a venodilatory effect and possible evidence for the pharmacologic effects of ONO-4232, occurred increasingly with increasing dose. Pharmacokinetic parameters appeared to be dose-proportional. The study results support further evaluation of the cardiovascular effects of this first-in-class selective left ventricular lusitropic and venodilatory drug in patients with acutely decompensated heart failure.

Safety, Tolerability, and Pharmacokinetic Profile of the Novel Translocator Protein 18 kDa Antagonist ONO-2952 in Healthy Volunteers.

PURPOSE: To investigate safety, tolerability, and pharmacokinetic properties of single and multiple doses of novel translocator protein 18 kDa antagonist ONO-2952 in healthy subjects. METHODS: Double-blind, placebo-controlled single (SAD) and multiple (MAD) dose escalation studies were conducted. Healthy men and women aged 18 to 55 years inclusive and without history of psychiatric disorders were eligible. Forty-eight volunteers received single doses of ONO-2952 (3, 10, 30, 100, 200, or 400 mg) or placebo under fasted conditions (SAD study), and 36 received ONO-2952 (30, 60, or 100 mg/d) or placebo for 21 consecutive days under fed conditions (MAD study). ONO-2952 10 and 200 mg were administered under fasted and fed conditions in the SAD study to investigate the effect of food on the absorption of ONO-2952. Safety assessments included adverse events, vital signs, 12-lead ECGs, and clinical laboratory evaluations. Plasma and urine pharmacokinetic profiles of ONO-2952 were determined. FINDINGS: Across both studies, mean age ranged from 29.8 to 39.8 years, most participants were white, and the proportion of female volunteers was 52%. No treatment or dose-related trends in adverse events were observed. The most frequent adverse events were headache and presyncope (n = 2 each [SAD study]) and constipation and headache (n = 3 each [MAD study]). All headache and constipation episodes were possibly related to the study drug. Plasma ONO-2952 concentrations peaked 2.5 to 3.5 hours (SAD study) and 3.0 to 4.0 hours (MAD study) postdose. ONO-2952 systemic exposure increased less than dose proportionally under fasted conditions. Fed conditions significantly increased exposure compared with fasted conditions: geometric mean ratios of Cmax (90% CIs) were 229% (176-299 [10 mg]) and 778% (623-971 [200 mg]), and AUClast were 159% (131-192 [10 mg]) and 382% (288-506 [200 mg]). In the MAD study, the systemic exposure of ONO-2952 increased in a slightly greater than dose-proportional manner. Geometric mean accumulation ratios (95% CI) of AUC24 were 2.50 (2.09-2.98 [30 mg]), 2.23 (1.85-2.68 [60 mg]), and 2.73 (2.10-3.55 [100 mg]); and Cmax were 1.65 (1.43-1.90 [30 mg]), 1.56 (1.31-1.85 [60 mg]), and 1.85 (1.38-2.49 [100 mg]). IMPLICATIONS: ONO-2952 was safe and well tolerated in these early clinical studies investigating safety, tolerability, and pharmacokinetic properties of single and multiple doses. ONO-2952 systemic exposure increased in a less than dose-proportional manner under fasted conditions and in a slightly greater than dose-proportional manner under fed conditions. These results support the progression of ONO-2952 to further studies in humans. SAD study: ClinicalTials.gov identifier: NCT01364441. MAD study: ClinicalTrials.gov identifier: NCT01489345.

IOP-Lowering Effect of ONO-9054, A Novel Dual Agonist of Prostanoid EP3 and FP Receptors, in Monkeys.

PURPOSE: The purpose of this study was to determine whether a better IOP reduction can be observed in conscious, normotensive monkeys treated with ONO-9054, a novel dual EP3 and FP receptor agonist, compared with prostaglandin F2α analogs. METHODS: The binding affinities and agonistic activities of ONO-AG-367, a carboxylic acid of ONO-9054, to prostanoid receptors were assessed. The IOP-lowering effect of ONO-9054 in monkeys was analyzed after a single (0.3, 3, or 30 µg/mL) or 7-day repeated (30 µg/mL, every day) topical ocular administration. Ophthalmologic and histopathologic evaluations of the eye were performed after 4-week ocular administration of ONO-9054 (30 µg/mL, twice a day) in monkeys. RESULTS: The ONO-AG-367 exhibited high affinity for both EP3 and FP receptors and potent agonist activity, with EC50 values of 28.6 nM for the EP3 receptor and 22.3 nM for the FP receptor. Single and repeated topical ocular administration of ONO-9054 caused IOP reductions in normotensive monkeys. The maximum IOP reductions on day 7 observed with ONO-9054 (7.3 ± 0.8 mm Hg) were significantly greater than those observed with latanoprost (50 µg/mL, 4.9 ± 0.4 mm Hg) or travoprost (40 µg/mL, 5.1 ± 0.6 mm Hg). In ophthalmologic and histopathologic evaluations, slight and transient mydriasis was occasionally observed and no histopathologic lesions attributable to ONO-9054 were noted. CONCLUSIONS: A more profound and longer-lasting reduction in IOP in normotensive monkeys can be observed with ONO-9054, which simultaneously stimulates both EP3 and FP receptors, compared with prostaglandin analogs.

A Novel Dual Agonist of EP3 and FP Receptors for OAG and OHT: Safety, Pharmacokinetics, and Pharmacodynamics of ONO-9054 in Healthy Volunteers.

PURPOSE: The use of a dual prostaglandin E3 (EP3) and prostaglandin F (FP) receptor agonist is a novel approach for the reduction of intraocular pressure (IOP) in open angle glaucoma and ocular hypertension and, as such, ONO-9054 may have benefits over existing therapies. The objectives of this phase I study were to assess the safety, tolerability, systemic pharmacokinetics (PK), and pharmacodynamics (PD) profiles of ONO-9054 (Sepetoprost), the prodrug of ONO-AG-367, in healthy, normotensive adults. METHODS: In this randomized, double-masked, placebo-controlled, single-dose escalating study, 48 male and female healthy volunteers each received a single drop of ONO-9054 0.3, 1.0, 3.0, 10.0, 20.0, or 30.0 µg/mL, or matching placebo in each eye. Blood samples of PK were taken up to 24 hours post dose; ocular and systemic safety, tolerability, and PD assessments were conducted up to approximately 72 hours post dose, and on day 7 at the follow-up visit. RESULTS: We found ONO-9054 was safe and well tolerated and ONO-AG-367 exhibited dose-dependent systemic PK with rapid elimination. The effect of PD was assessed by reduction in IOP, with the maximum change from baseline in IOP in these normotensive individuals of -28.23% achieved at the 30.0 µg/mL dose at 9 hours post administration. CONCLUSIONS: A single dose of the novel EP3 and FP receptor agonist ONO-9054 was safe and well tolerated in healthy volunteers at doses between 0.3 and 30.0 µg/mL and resulted in a significant reduction in intraocular IOP with maximum reduction at 9 hours post dose. This supports further evaluation of ONO-9054 for the treatment of ocular hypertension and open angle glaucoma. (ClinicalTrials.gov number, NCT01508988.).

Sterol Regulatory Element-Binding Protein-2 modulates human brain acyl-CoA hydrolase gene transcription.

The brain shows high catalyzing activity during hydrolysis of long-chain acyl-CoAs into fatty acids and CoA-SH. Brain acyl-CoA hydrolase (BACH) is responsible for most of the long-chain acyl-CoA hydrolyzing activity in the brain and is localized exclusively in neurons. We analyzed the human BACH gene promoter, focusing on transcriptional regulation by Sterol Regulatory Element-Binding Protein-2 (SREBP-2), which is a transcription factor that activates genes involved in cholesterol biosynthesis and uptake. When the nuclear form of SREBP-2 gene was transfected into human neuroblastoma cells, transcription of a BACH gene promoter-luciferase reporter gene was activated through a sterol regulatory element (SRE) motif. Moreover, a gel shift assay demonstrated that SREBP-2 specifically bound to the SRE motif. These results suggest that transcription of the BACH gene is activated by SREBP-2. This study also provides insights into BACH function in the interaction between the metabolism of acyl-CoAs and cholesterol in neurons.