Cyclerion Therapeutics had taken its lead drug candidate into the clinic, obtaining encouraging data in a rare disease. But the company was running out of cash to support that program and others in its pipeline. A key Cyclerion financial backer stepped in with a deal to acquire that asset and continue its development in a new biotech company.

That startup, the mitochondrial diseases-focused Tisento Therapeutics, formally launched on Monday, nearly three months after the deal was first announced. Cambridge, Massachusetts-based Tisento is backed by $81 million in Series A financing.

Tisento’s lead program is zagociguat, a small molecule previously known as CY6463 under Cyclerion. This drug is designed to penetrate the brain to stimulate soluble guanylate cyclase (sGC), an enzyme key to the nitric oxide signaling pathway. This pathway controls aspects of physiology throughout the body, including mitochondrial function.

Cyclerion was developing zagociguat for mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes, a rare disease typically shortened to “MELAS.” This disorder affects the energy-producing components of cells called mitochondria and leads to central nervous system problems, cognitive impairment, fatigue, and muscle weakness.

In mid-2022, Cyclerion announced data from an open-label Phase 1 study showing encouraging effects were observed on various aspects of MELAS in six of the eight patients in the study. Last October, Cyclerion announced it would hone its focus on mitochondrial disease, a strategy shift that led to the layoff of 45% of its staff. But cash continued to be problem. CEO Peter Hecht was part of a group that tried to buy some of Cyclerion’s assets to continue their development. The company’s independent board of directors unanimously turned down that proposal.

This past March, in its report of 2022 financial results, Cyclerion reported a cash position totaling just $13.4 million. In May, Cyclerion announced a deal to sell zagociguat and another asset, the preclinical CY3018, for $8 million cash and another $2.4 million to cover employee and development expenses for zagociguat. Cyclerion also received a 10% equity stake in Tisento as well as the right to purchase additional equity in the future. Hecht, who is also CEO of Tisento, personally invested $5 million in Cyclerion.

Tisento’s Series A financing includes participation of major Cyclerion shareholders, including Invus, Hecht, Polaris, and others. They are joined in the Tisento investor syndicate by Sanofi Ventures, Venrock, J. Wood Capital, and other unnamed investors.

Meanwhile, Cyclerion says it now has enough cash to last into 2025. Errol De Souza, chair of Cyclerion’s board, said in a prepared statement that the company will continue an “externalized business model” in which it targets later-stage, de-risked CNS assets that can be quickly advanced in development. In parallel, the company will explore ways to advance its systemic sGC stimulator drugs. The remaining pipeline includes praliciguat, a systemic sGC stimulator that is licensed to Akebia Therapeutics and is in clinical development for treating rare kidney diseases. Olinciguat is a clinical-stage vascular sGC stimulator that the company intends to out-license for cardiovascular diseases.

“We are very pleased to have found a good solution to advance our promising brain-penetrant sGC development programs on behalf of patients with significant unmet medical needs,” De Souza said. “In the midst of this extremely challenging financing climate for the biotech industry, we’re honored to partner with an excellent syndicate of investors.”

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