In December 2021, it was announced that Amunix had been acquired by Sanofi for an amount indicated as $1B. Active in SBIR for some6-7 years after start-up, the firm had been structured around developing prodrugs to bring the promise of potent immune-activating biotherapeutics to patients with solid tumor cancers. Leveraging the firm's proprietary T cell engager (XPAT™) and cytokine (XPAC) platforms the effort is to advance novel prodrugs that overcome the toxicity and immunogenicity challenges common to these therapeutic modalities via selective activation in the tumor microenvironment. By delivering breakthrough therapies that can safely harness the immune system, the effort is to conquer cancer and save lives. From the outsideof the firm's original establsihment in 2006, the approachhas been to operate as a technology licensing company. Management had previously forged agreements with various biopharmaceutical companies - Roche, Merck, Celgene, and Biogen - to leverage XTEN, a proprietary half-life extension technology, and Pro-XTEN, a next-generation prodrug technology. Pro-XTEN utilizes a protease-releasable XTEN polypeptide as a mask, thus enabling localized activation of potent therapies. This technology is designed to overcome a common challenge facing potent immune system activators: on-target, off-tumor toxicity. Pro-XTEN, which is the foundational technology for the XPAT and XPAC platforms, has been clinically validated, with the most advanced program utilizing the technology currently in a pivotal Phase 3 study for a non-oncology indication. The firm's lead development candidate currently is AMX-818 - an XPAT T cell engager targeting HER2+ solid tumors, toward the clinic
