The ATLAS Study NCT07156565 : A First-in-Human Phase 1/2 Trial of [Ac-225]RTX-2358 in Patients with Relapsed or Refractory FAP positive Soft Tissue Sarcoma

The ATLAS (Actinium Therapy for Late-stage Aggressive Sarcomas) Study, is an open-label, seamless, Phase 1/2 clinical study to evaluate safety, tolerability, dosimetry, biodistribution, pharmacokinetic (PK), and anti-tumor activity of [Ac-225]RTX-2358. [Ac-225]RTX-2358 is planned initially in patients with relapsed or treatment-resistant FAP positive soft tissue sarcoma. The study consists of two phases, an ascending administered activity phase (Phase1) and an expansion phase (Phase 2). In the Phase 1 portion of the trial patients will be divided into three groups, each group receiving a higher dose and/or a different dose schedule than the last. A modified “3 + 3” dose escalation with Phase 1 queue (IQ) design approach will be used, with potential backfill in cohorts.