Actinium Pharmaceuticals, Inc. announced that results from the Phase 3 SIERRA trial of Iomab-B have been accepted for an oral presentation and poster presentation at the 2024 European Hematology Association (EHA) Hybrid Congress being held June 13 ? 16, 2024, in Madrid, Spain. The Phase 3 SIERRA trial enrolled 153 patients ages 55 and above with active relapsed or refractory acute myeloid leukemia (r/r AML) and compared outcomes of patients receiving an Iomab-B led bone marrow transplant (BMT) to those of patients receiving physician's choice of care in the control arm.

Across all patients in SIERRA study, only patients receiving an Iomab-B led BMT achieved the trial's primary endpoint of durable complete remission with these patients having 92% 1-year survival and 69% 2-year survival with statistically significant higher event free survival. The SIERRA trial enrolled high-risk patients including those with one or more of the following: a TP53 mutation, advanced age up to 77 years old, complex cytogenetics and prior therapy including venetoclax and other targeted agents. In total, 24% (37/153) of the patients enrolled on SIERRA had a TP53 mutation, which is usually associated with limited treatment options and poor outcomes.

Median Overall Survival of 5.49 months observed in patients with a TP53 mutation receiving an Iomab-B led allogeneic bone marrow transplant compared to 1.66 months in patients that did not receive Iomab-B (hazard ratio=0.23, p=0.0002). Iomab-B EHA presentations titles are as follows: Oral Presentation: 131I-APAMISTAMAB-LED ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANT RESULTS IN IMPROVED SURVIVAL OUTCOMES IN R/R AML PATIENTS WITH HIGH-RISK TP53 MUTATIONS IN THE RANDOMIZED PHASE III SIERRA TRIAL. Poster Presentation: LONG TERM EFFICACY RESULTS OF THE SIERRA TRIAL: A PHASE 3 STUDY OF 131I-APAMISTAMAB-LED ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION VERSUS CONVENTIONAL CARE IN OLDER PATIENTS WITH ACTIVE, R/R AML.