Solstice Oncology

Solstice Oncology was a private biopharmaceutical company dedicated to developing next-generation, conditionally active immunotherapies for cancer. The company's primary focus was on engineering therapies that remain inactive in systemic circulation but become potent immune activators specifically within the tumor microenvironment, thereby reducing off-target toxicities. Its lead program centered on a 4-1BB (CD137) agonist designed to overcome the hepatotoxicity issues historically associated with this target. In July 2021, Solstice was acquired by Silverback Therapeutics to complement their Immuno-ADC platform and expand their oncology pipeline. Following the acquisition, its assets were integrated into Silverback's development programs.