Alethio Therapeutics Secures $90 Million for ATX-011 in Essential Thrombocythemia

Alethio Therapeutics has secured $90 million in Series A financing to develop its lead drug candidate for essential thrombocythemia. The funding round, which closed on November 5, 2026, was co-led by Sofinnova Partners and RA Capital Management with participation from founding investor Oxford Science Enterprises.

This capital will propel ATX-011 through IND-enabling studies and into Phase 1/2a clinical development. CEO Rohit Batta stated that the company now has the financing to run the clinical study, which will determine whether promising laboratory results translate to patients. The proceeds are intended to prepare the asset for Phase 3 development.

Target mechanism and preclinical validation

ATX-011 is a monoclonal antibody designed to bind G6B, a novel target expressed on disease-driving stem cells and megakaryocytes in myeloproliferative neoplasms. The target was validated across large cohorts of patient samples, showing selective marking of abnormal cells irrespective of the disease's driver mutation. G6B is also implicated in the development of bone marrow fibrosis.

In preclinical testing, an unconjugated G6B antibody produced controlled and reversible platelet reductions in nonhuman primates. Platelet counts fell by 80% after 96 hours of treatment and recovered as the antibody cleared from the system. Laboratory tests indicated ATX-011 does not directly activate human platelets, cause aggregation, or disrupt megakaryocyte maturation. The antibody is designed to enhance the body's existing platelet-clearance processes without altering G6B's normal function.

Dosing every three to four weeks is predicted to maintain normal platelet counts in patients with essential thrombocythemia. This remains pending confirmation in clinical trials.

Clinical development timeline and indications

The first clinical study of ATX-011 is expected to begin enrolling patients in the first half of 2028, pending regulatory approvals. This initial trial will assess safety, drug exposure, mechanism of action, and platelet normalization at 12 weeks as an early proof-of-concept readout.

ATX-011 is being developed for myeloproliferative neoplasms, a group that includes essential thrombocythemia, polycythemia vera, and primary myelofibrosis. Essential thrombocythemia involves uncontrolled platelet production and affects an estimated 140,000 to 150,000 patients in the United States. Current standard treatments include hydroxycarbamide and interferon.

The company, Alethio Therapeutics, was founded in late 2021 as Alethiomics by Oxford researchers Adam Mead and Beth Psaila. They identified G6B as highly expressed on abnormal stem cells in MPNs while being absent from healthy blood stem cells. The company's ARTEMIS platform uses single-cell analysis and computational methods on over 100 MPN patient samples to identify and validate drug targets.

Oxford Science Enterprises highlighted G6B's central role in its investment case, citing unique clinical insights from the founders. RA Capital's Maxwell DeNies pointed to G6B as a highly differentiated target with compelling human data. Sofinnova Partners' Graziano Seghezzi emphasized the evidence from patient samples and validation across diverse mutations. The financing is expected to transition Alethio into a clinical-stage company. Enrollment in the first clinical study is anticipated in the first half of 2028.