Keros Therapeutics Presents Additional Clinical Data from its KER-065 Program at the American Society of Bone and Mineral Research 2025 Annual Meeting

Rhea-AI Summary

Keros Therapeutics (NASDAQ: KROS) presented additional clinical data from its Phase 1 trial of KER-065 at the American Society of Bone and Mineral Research 2025 Annual Meeting. The trial, conducted in healthy male volunteers, demonstrated that KER-065, a modified activin receptor ligand trap, was generally well-tolerated with no serious adverse events related to treatment.

The study showed promising results for bone health, with sustained improvements in bone mineral density (BMD) through Day 141, particularly in whole body and lumbar spine measurements. The data supports KER-065's potential development for treating Duchenne muscular dystrophy and bone disorders, where bone loss occurs due to muscle weakness and corticosteroid use.

Positive

• Treatment with KER-065 was generally well-tolerated at all dose levels
• Demonstrated sustained improvements in bone mineral density through Day 141
• Showed positive changes in bone formation biomarkers and reduced bone resorption
• No serious adverse events related to treatment were reported

Negative

• One grade 4 treatment-emergent adverse event of elevated creatine kinase levels was observed

Insights

Clinical Pharmacologist

Keros' KER-065 shows positive bone biomarkers and sustained BMD improvements with good safety profile in Phase 1 trial.

The Phase 1 trial results for KER-065, Keros Therapeutics' modified activin receptor ligand trap, demonstrate promising clinical potential. The data reveal dual action on bone metabolism - simultaneously increasing bone formation while reducing bone resorption. This mechanism translated to measurable increases in bone mineral density (BMD), with improvements sustained through Day 141 (three months post-final dose). This prolonged efficacy window suggests a favorable pharmacodynamic profile that could potentially allow for less frequent dosing in future clinical applications.

The safety profile appears generally favorable, with no dose-limiting toxicities or serious adverse events reported. While one grade 4 elevated creatine kinase event occurred, investigators determined it was unrelated to treatment. Most adverse events were mild to moderate and resolved without intervention, indicating good tolerability across all tested dose levels.

These results provide strong pharmacological rationale for pursuing KER-065's development in Duchenne muscular dystrophy (DMD), where patients experience bone loss from both the underlying disease and corticosteroid treatment. The drug's demonstrated ability to improve BMD specifically in the lumbar spine is particularly relevant, as vertebral fractures are common complications in DMD patients on long-term corticosteroid therapy. The sustained effect on whole body BMD suggests KER-065 achieves a balanced modulation of osteoblast/osteoclast activity, which is essential for healthy bone remodeling and could address the dysregulated bone metabolism in DMD.

LEXINGTON, Mass., Sept. 08, 2025 (GLOBE NEWSWIRE) -- Keros Therapeutics, Inc. (“Keros”) (Nasdaq: KROS), a clinical-stage biopharmaceutical company focused on developing and commercializing novel therapeutics to treat a wide range of patients with disorders that are linked to dysfunctional signaling of the transforming growth factor-beta (“TGF-ß”) family of proteins, today announced that it presented additional clinical data from its Phase 1 clinical trial of KER-065 in healthy male volunteers at the American Society of Bone and Mineral Research 2025 Annual Meeting on Saturday, September 6, 2025.

“We are pleased to present additional data that highlights the broad therapeutic potential of KER-065, including its robust bone anabolic activity,” said Jasbir S. Seehra, President and Chief Executive Officer. “These data continue to demonstrate the potential of KER-065 in Duchenne muscular dystrophy, where bone loss occurs as a result of the progressive muscle weakness and chronic use of corticosteroids.”

Clinical Presentation

Phase 1 Trial in Healthy Participants of KER-065, a Modified Activin Receptor Ligand Trap, Supports Development in Duchenne Muscular Dystrophy and Bone Disorders

This Phase 1 clinical trial was a randomized, double-blind, placebo-controlled, two-part dose escalation (single and multiple ascending dose) trial in healthy male volunteers. The primary objectives of this trial were to assess safety, tolerability and pharmacokinetics of KER-065. Exploratory endpoints include assessments of the pharmacodynamic effect on bone, adipose, muscle, cardiac tissue and fibrosis. Initial topline data from this trial was reported in March 2025.

As of the final data cut-off date of April 29, 2025, treatment with KER-065 was generally well-tolerated at all dose levels tested. No dose-limiting toxicities or serious adverse events were reported. One grade 4 treatment-emergent adverse event of elevated creatine kinase levels was observed, but deemed unrelated to treatment. The majority of the adverse events that were observed were mild to moderate in severity and resolved.

Additional results from this trial, as of the data cut-off date, demonstrated that treatment with KER-065 resulted in:

• Changes in bone biomarkers of increased bone formation and reduced bone resorption that were consistent with tissue level changes, as demonstrated by observed increases in bone mineral density (“BMD”)
• Whole body BMD improvements at Day 85 that were sustained through Day 141 (three months after the last dose in the multiple ascending dose cohorts), suggesting a balance between osteoblast and osteoclast activity
• Increased lumbar spine BMD following three doses that were sustained through Day 141
  

About KER-065

KER-065 is a novel ligand trap comprised of a modified ligand-binding domain derived from activin receptor type IIA and activin receptor type IIB that is fused to the portion of the human antibody known as the Fc domain. KER-065 is designed to act as a ligand trap and inhibit the biological effects of myostatin and activin A, two ligands that signal through activin receptors, to increase skeletal muscle regeneration, increase muscle size and strength, reduce body fat, reduce fibrosis of the skeletal muscle and increase bone strength. We are developing KER-065 for the treatment of neuromuscular diseases, with an initial focus on DMD.

About Duchenne Muscular Dystrophy (DMD)

DMD is the most common form of muscular dystrophy and results in muscle degeneration and premature death. DMD results from the lack of functional dystrophin protein that helps promote myofiber stability, caused by a gene mutation. The lack of dystrophin, an important structural component of muscle cells, causes muscle cells to have increased susceptibility to damage and to progressively die. Additionally, the absence of dystrophin in muscle cells leads to significant cell damage and ultimately causes muscle cell death and the replacement of muscle with fibrotic and fatty tissue. The replacement of muscle fibers with fatty and fibrotic tissue leads to progressive loss of muscle strength and function leading to immobility and respiratory and cardiac complications. In DMD patients, heart muscle cells progressively die and are replaced with scar tissue. This cardiomyopathy eventually leads to heart failure, which is currently the leading cause of death among those with DMD. The National Organization for Rare Disorders estimates that approximately one in every 3,500 male births is affected by DMD worldwide.

About Keros Therapeutics, Inc.

Keros is a clinical-stage biopharmaceutical company focused on developing and commercializing novel therapeutics to treat a wide range of patients with disorders that are linked to dysfunctional signaling of the TGF-ß family of proteins. Keros is a leader in understanding the role of the TGF-ß family of proteins, which are master regulators of the growth, repair and maintenance of a number of tissues, including blood, bone, skeletal muscle, adipose and heart tissue. By leveraging this understanding, Keros has discovered and is developing protein therapeutics that have the potential to provide meaningful and potentially disease-modifying benefit to patients. Keros’ lead product candidate, KER-065, is being developed for the treatment of neuromuscular diseases, with an initial focus on DMD. Keros’ most advanced product candidate, elritercept, is being developed for the treatment of cytopenias, including anemia and thrombocytopenia, in patients with myelodysplastic syndrome and in patients with myelofibrosis.

Cautionary Note Regarding Forward-Looking Statements

Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. Words such as “anticipates,” “believes,” “continue,” “expects,” “enable,” “intention,” “potential” and “will” or similar expressions are intended to identify forward-looking statements. Examples of these forward-looking statements include statements concerning: Keros’ expectations regarding its strategy, progress and timing of its clinical trials for KER-065; and the broad therapeutic potential of KER-065. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. These risks and uncertainties include, among others: Keros’ limited operating history and historical losses; Keros’ ability to raise additional funding to complete the development and any commercialization of its product candidates; Keros’ dependence on the success of its product candidates, KER-065 and elritercept; that Keros may be delayed in initiating, enrolling or completing any clinical trials; competition from third parties that are developing products for similar uses; Keros’ ability to obtain, maintain and protect its intellectual property; and Keros’ dependence on third parties in connection with manufacturing, clinical trials and preclinical studies.

These and other risks are described more fully in Keros’ filings with the Securities and Exchange Commission (the “SEC”), including the “Risk Factors” section of the Company’s Quarterly Report on Form 10-Q, filed with the SEC on August 6, 2025, and its other documents subsequently filed with or furnished to the SEC. All forward-looking statements contained in this press release speak only as of the date on which they were made. Except to the extent required by law, Keros undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made.

Contacts

Investor Contact:
Justin Frantz
jfrantz@kerostx.com
617-221-6042

Media Contact:
Mahmoud Siddig / Adam Pollack / Viveca Tress
Joele Frank, Wilkinson Brimmer Katcher
(212) 355-4449

FAQ

What were the key findings from Keros Therapeutics' (KROS) Phase 1 trial of KER-065?

The trial showed KER-065 was generally well-tolerated, with sustained improvements in bone mineral density through Day 141 and positive changes in bone formation biomarkers.

How long did the bone density improvements from KER-065 last in the Keros Phase 1 trial?

The bone mineral density improvements were sustained through Day 141 (three months after the last dose) in both whole body and lumbar spine measurements.

What were the safety results of KER-065 in Keros Therapeutics' Phase 1 trial?

KER-065 was generally well-tolerated with no serious adverse events related to treatment. Most adverse events were mild to moderate and resolved, though one unrelated grade 4 elevated creatine kinase event occurred.

How could KER-065 potentially help patients with Duchenne muscular dystrophy?

KER-065 shows potential to address bone loss in Duchenne muscular dystrophy patients, which occurs due to progressive muscle weakness and chronic corticosteroid use.

What type of study was the Keros Therapeutics KER-065 Phase 1 trial?

It was a randomized, double-blind, placebo-controlled, two-part dose escalation trial (single and multiple ascending dose) conducted in healthy male volunteers.