UK startup Alethio Therapeutics raised an oversubscribed $90 million Series A to advance ATX-011, a first-in-class monoclonal antibody targeting G6B for essential thrombocythemia. The University of Oxford spinout plans to move ATX-011 through Phase I/IIa studies, with an eye toward Phase III readiness after initial first-in-human efficacy and safety signals. Alethio is positioning the antibody as mutation-agnostic across myeloproliferative neoplasms by targeting platelet-associated biology and upstream effects on MPN-initiating stem cells. The financing was co-led by Sofinnova Partners and RA Capital, with support from Oxford Science Enterprises and partners including Cancer Research Horizons and the University of Oxford.