Actinium Pharmaceuticals Inc. (NYSE AMERICAN: ATNM) presented preclinical data at the American Association for Cancer Research Annual Meeting showing how its drug candidate Actimab-A works against acute myeloid leukemia cells.

The company reported that Actimab-A demonstrated activity across multiple AML models regardless of mutation status when tested in laboratory studies. The drug showed effectiveness in primary patient samples with various genetic mutations including FLT3, KMT2A, NPM1, IDH1, IDH2, and TP53.

Preclinical studies showed that combining Actimab-A with standard treatments including revumenib, gilteritinib, and azacitidine enhanced cancer cell killing in laboratory models. Gene analysis revealed that the combinations altered cellular programs, reducing proliferation signals while increasing differentiation and cell death pathways.

Actimab-A is a radiotherapy that delivers Actinium-225, an alpha-emitting radioisotope, to CD33-expressing AML cells. The company has tested the drug in more than 150 AML patients across multiple clinical trials as both a single treatment and in combinations.

In a Phase 1 trial for relapsed/refractory AML, Actimab-A combined with CLAG-M chemotherapy produced an 83% overall response rate and 75% minimal residual disease negativity at the recommended Phase 2 dose, according to the company.

Actinium is advancing the drug through a collaboration with the National Cancer Institute, including an ongoing frontline trial combining Actimab-A with venetoclax and ASTX-727 in newly diagnosed AML patients. The company is seeking a development partner for a planned Phase 2/3 registrational study.

The data was presented in a poster titled "Actimab-A, a CD33-Targeted Actinium-225 Radioconjugate, Drives Mutation-Agnostic Anti-Leukemic Activity and Synergizes with Standard Therapies in AML Through Transcriptional Reprogramming."