SixPeaks Bio emerged from stealth Wednesday with up to $110 million, a deal with AstraZeneca and plans to take weight-loss candidates designed to preserve muscle mass toward the clinic.
SixPeaks Bio has emerged from stealth with up to $110 million for obesity R&D and an agreement that could see it acquired by AstraZeneca within two years, the startup said Wednesday.
Venture capital firm Versant Ventures founded SixPeaks at its site in Switzerland in 2022 to develop better therapies for weight loss. People can experience significant weight loss when taking GLP-1 receptor agonists such as Eli Lilly’s Zepbound (rirzepatide) and Novo Nordisk’s Wegovy (semaglutide) but they lose both fat and muscle. SixPeaks wants to help people preserve muscle mass while losing weight.
AstraZeneca sees promise in the idea. The drugmaker has committed up to $80 million in upfront and near-term payments to support SixPeaks over the next two years. In return, AstraZeneca has received an option to buy SixPeaks at an agreed price when the biotech files to study its lead candidate in humans.
SixPeaks raised a further $30 million in a Series A round led by Versant. AstraZeneca contributed to the financing round. The biotech will use the money to push two obesity drug candidates toward the clinic.
The pipeline is built on an activin IIA/B receptor antibody. Studies have shown inhibiting activin signaling drives significant increases in muscle mass, leading SixPeaks and other research groups to pursue the blockade of the receptors to potentially address the limitations of GLP-1 drugs.
Regeneron began a Phase II trial of molecules including the anti-activin A antibody garetosmab in March 2024. Eli Lilly acquired Versanis for a monoclonal antibody that binds activin type II A and B receptors in 2023 in deal worth up to almost $2 billion. A Phase II trial of Versanis’ antibody in combination with Wegovy is scheduled to reach primary completion this week.
SixPeaks is yet to reach human testing but said preclinical studies suggest it has best-in-class efficacy for muscle mass preservation. The claimed benefits are linked to improved potency, biophysical properties, and pharmacokinetics and pharmacodynamics, plus reduced off-target binding. SixPeaks has attached its antibody to a GLP-1 peptide to create a candidate that could both drive fat loss and muscle retention.
If AstraZeneca acquires SixPeaks, the candidates will slot into a pipeline that already includes a clutch of obesity programs. The company has an oral GLP-1 molecule, a long-acting amylin and a GLP-1/glucagon dual active peptide that are approaching Phase II. AstraZeneca sees opportunities to use the molecules in combination with other assets to treat overweight and obesity, as well as associated comorbidities.
At an investor day Tuesday, Martin Cowie, interim senior vice president for late-stage development at the AstraZeneca group handling obesity, said the company wants “high quality weight loss, not losing muscle as well as fat.” Cowie said maintaining muscle is “super important for the long term.” The long-acting amylin is one way AstraZeneca wants to help people retain muscle. SixPeaks could provide other options.
Nick Paul Taylor is a freelance pharmaceutical and biotech writer based in London. He can be reached on LinkedIn.
