Keros to Start Rinvatercept DMD Trial in Q1 2026, Plans ALS Regulatory Talks

Keros Therapeutics plans to initiate a phase II trial of its lead candidate rinvatercept (KER-065) in patients with Duchenne muscular dystrophy (DMD) in the first quarter of 2026. The company also intends to engage regulators in the second half of the year to discuss a potential phase II program in amyotrophic lateral sclerosis (ALS). Keros reported $383 million in cash, providing a runway into the first half of 2028.

Rinvatercept is a modified activin-receptor ligand trap designed to bind and inhibit TGF-β ligands that are negative regulators of muscle and bone, including activin A and myostatin, while reducing binding to BMP9 to avoid bleeding signals seen with earlier molecules. In phase I, the drug was generally well tolerated in healthy volunteers across single ascending doses (1 mg/kg to 5 mg/kg) and multiple ascending doses (1.25 mg/kg and 2 mg/kg for three months), with no dose-limiting toxicities or serious adverse events. Pharmacology signals included increased lean mass and thigh muscle volume, improvements in bone mineral density and bone biomarkers, and reductions in whole-body and visceral fat mass.

DMD is a severe, progressive, and ultimately fatal disease driven by lack of dystrophin protein, with no cures. Current approaches include glucocorticoids, exon-skipping therapies, gene therapy, and FDA-approved HDAC inhibitors, each with limitations. Preclinical and early clinical observations suggest rinvatercept could address multiple aspects of DMD, including muscle, bone, and fat parameters, and may mitigate negative consequences of glucocorticoids. The company also observed enhanced expression of truncated dystrophin when used with exon-skipping phosphorodiamidate morpholino oligomers (PMOs) and increased expression of utrophin in the absence of exon skipping. The FDA granted orphan drug designation for rinvatercept to treat DMD.

Keros is also advancing elritercept in partnership with Takeda under an exclusive license agreement announced in December 2024 and effective Jan. 16, 2025, covering worldwide rights excluding mainland China, Hong Kong and Macau. The deal included a $200 million upfront payment and more than $1.1 billion in potential milestones, with Takeda responsible for development in most territories. A phase III study, RENEW, is evaluating elritercept for anemia and thrombocytopenia in patients with myelodysplastic syndromes (MDS); the first patient was dosed in July 2025, triggering a $10 million milestone payment. A phase II study, RESTORE, is evaluating elritercept in myelofibrosis-associated cytopenias.

In August 2025, Keros discontinued its cibotercept program for pulmonary arterial hypertension and redirected resources to rinvatercept. The company implemented a workforce reduction of approximately 45%, resulting in about 85 full-time employees, and expects average annualized cost savings of roughly $17 million. Board and leadership changes were also announced in August 2025.

For the upcoming fourth-quarter results, the consensus estimate is $6.50 million in sales and a loss per share of 49 cents. Keros has beaten earnings estimates in three of the trailing four quarters, with an average surprise of 9,098.63% and a beat of 83.78% in the last reported quarter. Shares have surged 55.7% in the past year compared with the industry’s gain of 18.1%, and trade at 0.72 times tangible book value versus the industry average of 3.76.