Rationale Heart failure (HF) with preserved ejection fraction (HFpEF) has become the predominant type of HF. Obesity-related HFpEF is the most common phenotype, associated with an especially high burden of symptoms and physical limitations, and a poor quality of life. Pulmonary hypertension (PH) is a common feature of obesity-related HFpEF. HS135 is a novel decoy trap for Activins and Growth Differentiation Factors (GDFs), including myostatin, which are genetically and clinically validated targets in PH, obesity, and HF. HS135 is differentiated from other Activin and GDF targeting mechanisms via its potential for best-in-class multi-specific potency which results in increased therapeutic window and qualitatively differentiated efficacy in PH, HF and body composition in pre-clinical models. Therefore, HS135 holds promise as a potential novel treatment option for patients with obesity-related HFpEF and PH. HS135-003 is a Phase 1b clinical trial to assess the preliminary safety and efficacy of HS135 in patients with PH and HFpEF (PH-HFpEF). The innovative trial design employs remote pulmonary artery (PA) pressure sensor technology which allows for frequent monitoring of PH-related hemodynamics. Methods This ongoing, randomized, double-blind, placebo-controlled, multiple ascending dose study is actively enrolling up to 40 adult male and female patients diagnosed with PH-HFpEF at centers in the US. Patients with a CardioMEMS™ HF System implanted as a part of standard care and a BMI of ≥30 kg/m2 are eligible. Several dose levels of subcutaneous HS135 will be explored in sequential fashion with a primary endpoint of safety. Secondary endpoints will include change from baseline up to week 24 in mean PA pressure and mean PA diastolic pressure measured using CardioMEMS™. Additional assessments of hemodynamics, patient-reported symptoms and physical limitations, exercise function, as well as echocardiographic, morphological, body composition and biomarker measurements will be assessed. Patients who desire and can benefit from HS135 therapy will be offered to enter an open label extension period upon completion of the initial treatment period. Results In progress. Conclusion This is a Phase 1b trial in progress to assess the preliminary safety and efficacy of the novel Activin and GDF inhibitor HS135 in obese patients with PH-HFpEF. Ambulatory PA pressure measurements in addition to patient-reported outcomes, measures of exercise function, biomarker and body composition endpoints are expected to provide valuable data to evaluate safety, identify efficacy signals and inform further development.

Introduction: Activins and growth differentiation factors (GDFs) are known drivers of cardiopulmonary pathology. Sotatercept (ActRIIA-Fc), which targets activins and GDFs, has recently reported Phase 3 success in Group 1 PH. However, its potential is curtailed by incomplete target engagement at the clinical target dose. HS135 is a rationally designed activin receptor-based trap with best-in-class in vivo target engagement of pathological activins and GDFs, while sparing BMP-9. HS135's differentiated efficacy profile was explored in preclinical models of Group 1 and 2 PH, and compared to ActRIIA-Fc. Methods: Efficacy in Group 1 and 2 PH was assessed using the 4-week rat monocrotaline (MCT) and the mouse transaortic constriction (TAC) models, respectively. In each case, HS135 was compared to ActRIIA-Fc, and tissue remodelling in the heart and lungs was assessed by IHC and RNA-seq. Results: Administration of MCT deregulated pathways related to inflammation and energy balance in the right ventricle, which were only modestly improved by ActRIIA-Fc. On the other hand, these pathways in HS135-treated animals were nearly indistinguishable from naïve mice. Similarly, in the lung, HS135 was more efficacious than ActRIIA-Fc at improving inflammation markers. In the TAC model, HS135, but not ActRIIA-Fc, completely reversed lung remodelling, and returned expression of genes related to fibrosis and heart failure back to baseline in the left ventricle. Conclusion: The best-in-class target engagement profile of HS135 translates into superior and differentiated heart and lung efficacy in Group 1 and 2 PH models, which warrants further exploration in clinical trials.

Introduction Six million patients in the US have left-sided heart failure (HF), a majority of which exhibit preserved Ejection Fraction (HFpEF). Obesity is an established risk factor for the development of HF, particularly HFpEF, with an estimated 80% of HFpEF patients living with obesity. Novel treatments that address both HF pathology and obesity are thus urgently needed. Activin and growth differentiation factor (GDF) cytokines are genetically and clinically validated drivers of HF and obesity. HS135 is a novel, rationally designed Activin and GDF ligand trap with a best-in-class ligand neutralization profile to treat HF with obesity. Here, we explored the cardiac and metabolic efficacy of HS135 in preclinical models of HF including obesity-associated HFpEF. Methods The transverse aortic constriction (TAC) and High-Fat Diet (HFD)/L-NAME mouse models were used to explore the potential of HS135 in left-sided HF and obesity-associated HFpEF, respectively. Fourteen days post-TAC surgery, animals were treated with 3, 10 and 30 mg/kg HS135 twice weekly for 28 days. Obesity-associated HFpEF was established by feeding mice HFD in combination with L-NAME supplied in drinking water ad libitum for 5 weeks before initiating twice weekly treatment with HS135 (5 and 25 mg/kg), empagliflozin (10 mg/kg daily), or both (25 mg/kg twice weekly and 10 mg/kg daily, respectively) for three weeks. In both the TAC and HFD/L-NAME models, changes in heart function, body composition, as well as plasma biomarkers were evaluated at the end of the study. Tissue remodelling in the heart and lungs was assessed by IHC and gene expression analyses. Results In the TAC model, HS135 achieved rebalancing of pathological Activin/GDF signalling, reversed markers of LV failure and fibrosis, and was efficacious at reversing lung remodeling. RNA sequencing of the LV revealed that TAC surgery negatively affected genes associated with cellular respiration and mitochondrial function while up-regulating genes associated with fibrotic adaptation. HS135 dose-dependently normalized these expression profiles and was efficacious at improving gene expression associated with positive metabolic function while reducing inflammatory pathways. In the HFD/L-NAME model, HS135 and/or empagliflozin were efficacious in normalizing left atrium weight, left-ventricular posterior wall thickness, and cardiac output. Importantly, HS135, but not empagliflozin, led to profound increases in skeletal muscle mass while decreasing white adipose tissue mass. As a consequence, HS135, but not empagliflozin, normalized lean over fat mass ratio, and induced a more metabolically favourable muscle gene expression profile. Furthermore, HS135 was able to improve circulating biomarkers of adiposity corroborating HS135's effect on improving body composition and metabolic health. Conclusion HS135's best-in-class ligand neutralization profile uniquely improves HF and metabolism in preclinical models of experimental heart failure. Collectively, these data support the development of HS135 as a novel agent in cardiometabolic disease, including obesity-associated HF.

PDF file - 60K, Examination of gene alterations relevant to spontaneous melanoma brain metastases

PDF file, 297KB, TGF-B1 neutralization using a (TBRII)2 trap having a natural or artificial linker sequence.

PDF file - 39K, Examination of levels of gene expression in modified (induced overexpression and knockdown) melanoma cell lines

Abstract Disclosure: G. Schang: Employee; Self; 35Pharma Inc. M. Poujol de Molliens: Employee; Self; 35Pharma Inc. E. Brûlé: Employee; Self; 35Pharma Inc. C. Chauvet: Employee; Self; 35Pharma Inc. J. Denis: Employee; Self; 35Pharma Inc. A. Sours: Employee; Self; 35Pharma Inc. V. Ganesh: Employee; Self; 35Pharma Inc. G. Tremblay: Employee; Self; 35Pharma Inc. J. Schoelermann: Employee; Self; 35Pharma Inc. M. O'Connor-McCourt: Employee; Self; 35Pharma Inc. Introduction: Novel anti-obesity medications including incretin mimetics have revolutionized the pharmacotherapy of obesity and type 2 diabetes, leading to unprecedented weight loss and clinically meaningful improvement of glucose metabolism and cardiometabolic health. However, this loss of fat mass is accompanied by undesirable loss of lean body mass (LBM) which can account for 15 - 40% of overall weight loss. Loss of LBM by incretin-based therapies negatively impacts resting metabolic rate, leading to a weight loss plateau and often unsustainable results. The preservation, or even increase, of LBM is therefore a desirable treatment goal for obesity pharmacotherapy and improvement of overall health. Activins and growth differentiation factors (GDFs), which are members of the TGF-beta superfamily, are validated targets controlling body composition and metabolism. Specifically, blockade of activins and GDFs has anabolic effects in metabolically active tissues such as skeletal muscle and brown adipose tissue, while reducing white adipose tissue mass. Therefore, specific and selective blockade of activins and GDFs represents a novel anti-obesity treatment strategy which can act orthogonally to current anti-obesity medications. Aims and objectives: HS235 is an activin receptor ectodomain-based (ActR) Fc-fusion protein that has been rationally designed to attain optimal inhibition of ligands controlling body composition in obesity. Methods: A structure-assisted rational molecular engineering approach coupled with cell-based potency screening was employed to design HS235. In vivo target engagement and pharmacodynamic response to HS235 were assessed in mice by quantifying metabolic biomarkers including muscle hypertrophy, muscle and fat gene expression, as well as plasma metabolites. To further validate the anti-obesogenic potential of HS235, diet-induced obese (DIO) mice were injected with HS235, an incretin mimetic, or a combination of both. Fat mass, LBM, glucose metabolism, exercise tolerance, and biomarker readouts were assessed at the end of study. Results: In cell-based assays, HS235 potently and selectively neutralized activins and GDFs implicated in body composition. This translated to complete in vivo target engagement and pharmacodynamic response. In a DIO mouse model, both HS235 and the incretin mimetic significantly improved metabolic parameters and decreased fat mass, but only HS235 increased LBM, while incretin-based treatment led to LBM loss. Importantly, the addition of HS235 to the incretin mimetic prevented this loss of LBM. Conclusion: Potent and selective inhibition of activins and GDFs by HS235 represents a novel LBM preserving weight loss strategy. Collectively, these data support the development of HS235 as a novel anti-obesity agent that may also complement currently approved incretin-based medications. Presentation: Friday, June 16, 2023

PDF file, 971KB, Assessment of the effects of TGF-B and (TBRII)2 trap on 4T1 cells in vitro.

PDF file - 37K, Role of EDNRB in melanoma cell proliferation and intracranial melanoma growth

PDF file - 25K, Examination of the role of BCL2a1 in intracranial tumor growth

PDF file, 832KB, Schematics and molecular models of single-chain activin and BMP traps.

PDF file, 243KB, Improved neutralization of BMP-2 using single-chain bivalent trap (BMPR1a)2 compared to monovalent receptor BMPR1a-ED.

PDF file - 26K, QRT-PCR examination of levels of expression of additional genes highlighted by microarray analysis

PDF file, 2243KB, Molecular dynamics analysis of the (TBRII)2 trap in complex with TGF-B3.

PDF file, 293KB, Quantification of proliferating cells in 4T1 tumors.

PDF file - 158K, Comparison of EDRNA vs. EDNRB expression and EDNRB immunostaining in clinical samples of primary melanoma and melanoma metastases (lymph node, brain and lung)

PDF file - 108K, Confirmation of ET1 and ET3 expression in brain and lung