Surge Therapeutics has raised money to take its extended-release biodegradable hydrogel into the clinic, reeling in $26 million to test its belief that implanting the scaffolds after surgery will improve outcomes in solid tumor patients.

Surgical resection remains a mainstay of solid tumor treatment but can leave cancer cells behind, both at the site of the procedure and in other parts of the body. The presence of remaining cells raises the risk of recurrence and metastasis. Equally, the surgery removes tumor-specific leukocytes and tumor antigens, which may help establish immunity against the cancer, and produces an immunosuppressive state.

“Even after a tumor has been removed, it is common for a small number of cancer cells to remain behind, whether at the site of the primary tumor or elsewhere in the body. Indeed, 40% of cancer patients who undergo surgery relapse within five years, so this is a major unmet medical need,” Surge CEO and founder Michael Goldberg said in a statement.

Surge spun out of Goldberg’s laboratory at Harvard Medical School to tackle the shortcomings of surgery. The biotech is built on the laboratory’s development of hydrogel scaffolds that gradually release agonists of innate immunity, including agonists of TLR7/8 or STING.

Investors see promise in the approach. Camford Capital led the series A round with assists from Khosla Ventures, Intuitive Ventures, Pitango HealthTech, 8VC, Alumni Ventures and the Cancer Research Institute. Surge will use the money to expand its team and start clinical trials.

The investors put up the money after seeing preclinical data on the approach. Putting the biodegradable hydrogel in the tumor resection site in animals yielded better outcomes than systemic or local delivery of the therapy. Goldberg and his collaborators linked the therapy to changes including increased numbers of natural killer cells that showed the post-surgery environment went from suppressing to stimulating the immune system.