Sonnet BioTherapeutics is a clinical-stage biotech developing engineered cytokine therapies for cancer and neurological diseases. Its core technology is the proprietary FHAB (Fully Human Albumin Binding) platform, which links cytokines to albumin to extend half-life, improve tumor targeting, and reduce toxicity. The lead asset, SON-1010 (IL12-FHAB), is in two active Phase 1/Phase 1b-2a trials: one combining SON-1010 with trabectedin in soft-tissue sarcoma, and one combining SON-1010 with Roche's atezolizumab in platinum-resistant ovarian cancer under a Roche/Genentech collaboration. A third program, SON-080 (low-dose IL-6), targets peripheral neuropathy and has been licensed to Alkem Laboratories for the Indian market. SON-1210, a bifunctional IL-12/IL-15 candidate targeting pancreatic cancer, is advancing toward an investigator-initiated Phase 1/2a trial. Sonnet has no approved products and no commercial revenue, funding operations through equity and debt financings. Its long-term model relies on out-licensing or partnering pipeline assets to larger pharma companies. Sonnet manages costs through an outsourced model, using a CDMO in India for manufacturing and running trials in Australia to benefit from government R&D tax credits. In late 2025, Sonnet completed a business combination with Hyperliquid Strategies, becoming a wholly-owned subsidiary trading under "PURR" on Nasdaq.