First Patient Dosed in Phase 1 Trial Evaluating Relapsed/Refractory AML Treatment

Actinium Pharmaceuticals, Inc has announced that the first patient was dosed in a phase 1 trial studying the company’s Actimab-A in combination with CLAG-M for patients with relapsed or refractory (r/r) acute myeloid leukemia (AML), which is being conducted at the Medical College of Wisconsin.

Actinium previously received IND clearance from the US Food and Drug Administration (FDA) this past March for the combination therapy.

Actimab-A is an antibody radio-conjugate (ARC) made of the anti-CD33 monoclonal antibody lintuzumab and classified with the radioisotope actinium-225. On almost all AML cells, CD33 is an expressed marker.

“Actimab-A has demonstrated promising activity as a single agent in difficult to treat patient populations that we attribute to its targeting ability, potency, and tolerability,” stated Dr Mark Berger, Actinium’s chief medical officer in a recent statement. “We are excited to be leveraging these strengths of Actimab in a combination regimen to bring this potentially important therapy to a greater number of patients in indications that need improved outcomes.”

“We are confident that the addition of Actimab to a salvage chemotherapy regimen has the potential to improve outcomes through improved response rates and by increasing the number of patients that can receive a bone marrow transplant,” he added.

The phase 1 dose-escalation trial is assessing a single administration of Actimab-A post CLAG-M treatment in addition to evaluating safety, tolerability, response rates, rates of bone marrow transplant (BMT), progression-free survival (PFS), and overall survival (OS). Safely administering the maximum-tolerated dose of Lintuzumab-AC225 at 0.75uCi/kg through the course of 1 year currently serves as the current endpoint. Monitoring toxicities of the combination serves as the secondary endpoint.

Actinium’s CD33 ARC technology is a program that includes a targeted therapy for targeted conditioning of the bone marrow with Ac²²⁵-lintuzumab as a single agent and with novel combinations. It has been studied in over 100 patients to date and is the only CD33 targeting agent being studied in a broad range of diseases in which the CD33 antigen is expressed, including AML, myelodysplastic syndrome (MDS) and multiple myeloma. CLAG-M is a salvage chemotherapy regimen commonly used to treat patients with AML that consists of cladribine, cytarabine, filgrastim, and mitoxantrone.

“Through the utilization of targeted radioisotopes, we are able to add a new modality of treatment to a salvage cytotoxic chemotherapy regimen with the aim of improving efficacy,” Sandesh Seth, Actinium’s Chairman and CEO, added. “Further, we can apply our ARC technology to targeted conditioning to enable a bone marrow transplant that we will explore in this trial as well as our anticipated Actimab-MDS trial.”