Parabilis Medicines raised $305 million in a Series F financing to push its Helicon platform and lead candidate, zolucatetide, toward later-stage testing. The round, led by RA Capital, Fidelity and Janus Henderson, values Parabilis above prior rounds and funds expansion of clinical programs targeting intracellular, historically 'undruggable' proteins such as components of the beta-catenin pathway. Parabilis’ Helicon peptides are designed to penetrate cells and engage flat protein surfaces that small molecules and antibodies struggle to reach. The cash infusion positions the company to accelerate clinical development and signals investor appetite for platforms that can address difficult intracellular oncology targets. Company executives have previously signaled openness to an eventual IPO; this Series F strengthens Parabilis’ balance sheet ahead of potential late-stage milestones and public-market timing.