OS Animal Health is developing OST-HER2, an immunotherapy for canine osteosarcoma that utilizes a bioengineered Listeria vector to target the HER2 protein. In a Phase 2 trial, the combination of OST-HER2 and radiation significantly improved survival rates compared to radiation alone, with a 2-year survival rate of 20% versus 1%. The company is currently engaging in a 'test the waters' campaign under Regulation Crowdfunding to gauge investor interest.