Development of a long‐acting relaxin analogue, LY3540378, for treatment of chronic heart failure

Abstract

Background and Purpose: Chronic heart failure, a progressive disease with limited treatment options currently available, especially in heart failure with preserved ejection fraction (HFpEF), represents an unmet medical need as well as an economic burden. The development of a novel therapeutic to slow or reverse disease progression would be highly impactful to patients and society. Relaxin-2 (relaxin) is a human hormone regulating cardiovascular, renal, and pulmonary adaptations during pregnancy. A short-acting recombinant relaxin, Serelaxin, demonstrated short-term heart failure symptom relief and biomarker improvement in acute heart failure trials. Here, we present the development of a long-acting relaxin analogue to be tested in the treatment of chronic heart failure.Experimental Approach: LY3540378 is a long-acting protein therapeutic composed of a human relaxin analogue and a serum albumin-binding VHH domain.Key Results: LY3540378 is a potent agonist of the relaxin family peptide receptor 1 (RXFP1) and maintains selectivity against RXFP2/3/4 comparable to native relaxin.The half-life of LY3540378 in preclinical species is extended through high affinity binding of the albumin-binding VHH domain to serum albumin. When tested in a single dose administration, LY3540378 elicited relaxin-mediated pharmacodynamic responses, such as reduced serum osmolality and increased renal blood flow in rats.In an isoproterenol-induced cardiac hypertrophy mouse model, treatment with LY3540378 significantly reduced cardiac hypertrophy and improved isovolumetric Abbreviations: albVHH, albumin binding variable heavy chain domain of a heavy-chain antibody; CMC, chemistry, manufacturing, and controls; FcRn, neonatal Fc receptor; NHP, nonhuman primate; RXFP1, relaxin family peptide receptor 1; RXFP2, relaxin family peptide receptor 2; SPR, surface plasmon resonance.

Identification of Novel Series of Potent and Selective Relaxin Family Peptide Receptor 1 (RXFP1) Agonists

“…In the said trial, serelaxin failed to lower the incidence of death from any cause after 180 d following a single 48 h infusion and was similarly without significant impact on reducing incidence of worsening of HF at 5 days relative placebo . Many attempts have been made to maintain the biological actions of relaxin H2 while extending its short half-life by chemical modifications such as truncation and conjugation. − If successful, these protein engineering approaches could enable the desired sustained target engagement (TE) at RXFP1 considered necessary to halt and potentially reverse chronic disease progression but would nonetheless likely require an injectable formulation.…”

Emergent Peptides of the Antifibrotic Arsenal: Taking Aim at Myofibroblast Promoting Pathways

“…Much like drugs, the susceptibility of peptides to rapid degradation and unspecific uptake, whether by circulating cells or the cells of off-target organs, ultimately restricts efficacy and increases the risk of off-target effects and toxicity. An exemplary effort in prolonging the in vivo activity of a peptide was presented by Verdino et al [ 53 ], wherein they conjugated single-chain RLX to the serum-albumin binding VHH domain to yield the relaxin analogue, LY3540378. The long-acting RLX analogue maintained selective receptor binding and activity comparable to native H2-relaxin hormone.…”

R2R01: A long‐acting single‐chain peptide agonist of RXFP1 for renal and cardiovascular diseases

“…Several approaches including small molecule agonists of RXFP1, single‐chain peptides like R2R01, recombinant forms of relaxin fused with albumin binders, or mRNA‐based therapeutics have been developed to allow longer durations of dosing and more convenient use in patients' daily life. Several of these compounds including R2R01 have completed Phase 1 and their safety and efficacy evaluation are ongoing (Magni, 2023; Verdino et al, 2023).…”

“…In addition, RXFP1 agonists have anti-fibrotic properties, and fibrosis is a common feature of many kidney diseases that can lead to progressive loss of function (Samuel et al, 2017). (Magni, 2023;Verdino et al, 2023).…”

“…Relaxin is a heterodimeric two-chain peptide hormone structurally related to insulin. Different options to extend the pharmacokinetic half-life of relaxin-2 include PEGylation, fatty acid (Muppidi et al 2019) Fc fusion (e.g., AZD3427), or fusion with the serum albumin binding VHH domain (albVHH) (LY3540378) (Verdino et al, 2023). In parallel, small molecule agonists of RXFP1 were identified (Sabnis, 2022), and pioneering studies showed that a single-chain peptide derived from the relaxin B chain (B7-33) maintains activity as a functional agonist for RXFP1, providing an important step towards simplification of the relaxin structure (Hossain et al, 2016).…”