A Phase 1 Study of Sea-CD70 in Myeloid Malignancies

Background

SEA-CD70 is being developed in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Current treatment options are limited for patients (pts) with relapsed or refractory (r/r) MDS or r/r AML and outcomes remain poor. SEA-CD70 is an investigational humanized, non‑fucosylated monoclonal antibody targeting CD70. Expression of CD70 is limited in normal tissue, but is aberrantly expressed on malignant myeloid blasts while absent from healthy hematopoietic progenitor cells. CD70 and its ligand, CD27, may play a role in malignant blast cell survival and/or tumor immune evasion. SEA-CD70 uses a novel sugar‑engineered antibody (SEA) platform to produce a non-fucosylated antibody with enhanced effector function. The proposed mechanism of action of SEA-CD70 includes elimination of CD70 positive cells via enhanced antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and mediation of complement‑dependent cytoxicity (CDC). Additionally, SEA‑CD70 has the potential to block the interaction of CD70 with CD27, which may disrupt signals that enhance blast proliferation and survival and may modulate the immune system to limit immune evasion and increase antigen specific T cell responses.

Methods

SGNS70-101 is a phase 1, open-label, multicenter, dose-escalation, and cohort expansion study designed to establish the safety, tolerability, and preliminary activity of SEA-CD70 in pts with myeloid malignancies (NCT04227847). Dose escalation is ongoing. In dose escalation, pts must have r/r MDS with 5-20% blasts which has failed prior treatment with a hypomethylating agent (HMA), and have no other therapeutic options known to provide clinical benefit for MDS. After conclusion of dose escalation, monotherapy expansion cohorts will be opened for pts with MDS and for pts with AML. Primary objectives are to evaluate the safety and tolerability, and to determine the maximum tolerated dose (MTD) or recommended expansion dose of SEA-CD70. Secondary objectives are to assess antitumor activity, PK, and immunogenicity of SEA-CD70. Once dose escalation is complete and the recommended monotherapy dose is identified, combination cohorts will be considered in AML and MDS. The study is currently enrolling with sites opening in the US and EU.