Actinium Pharmaceuticals, Inc. announced its presence at the upcoming Tandem Meetings: Transplantation & Cellular Therapy Meetings of the American Society for Transplantation and Cellular Therapy (ASTCT) and the Center for International Blood & Marrow Transplant Research (CIBMTR) being held February 15 – 19, 2023 at the World Center Marriott in Orlando, Florida. Actinium will host an investor conference call and webcast to present full topline results from its pivotal Phase 3 SIERRA trial of Iomab-B at 6:00 PM EST on Saturday, February 18, 2023. The investor conference call will follow the late-breaker presentation of the full Phase 3 SIERRA trial results.

In addition, Iomab-B will be highlighted in a CME Event titled, "The Convergence of Innovative Therapy and AlloHCT in AML: Applying Current Evidence to Improve Outcomes Across Patient Populations. Iomab-B is a first-in-class targeted radiotherapy intended to improve patient access to potentially curative BMT by simultaneously and rapidly depleting blood cancer, immune and bone marrow stem cells that uniquely express CD45. Multiple studies have demonstrated increased survival in patients receiving BMT, however, an overwhelming majority of patients with blood cancers do not receive BMT as current approaches do not produce a remission, which is needed to advance to BMT, or are too toxic.

Studied in over 400 patients, prior studies with Iomab-B have demonstrated nearly universal access to BMT, increased survival and tolerability in multiple clinical trials including the recently completed pivotal Phase 3 SIERRA trial in patients with active (leukemic blasts >5%), relapsed or refractory acute myeloid leukemia (r/r AML) age 55 and above. The SIERRA trial produced positive topline results, meeting its primary endpoint of durable Complete Remission (dCR) of 6 months with statistical significance (p<0.0001). Actinium intends to submit a Biologics License Application (BLA) seeking approval for Iomab-B to address patients age 55+ with r/r AML who cannot access BMT with currently available therapies.

Iomab-B has been granted Orphan Drug Designation from the U.S. Food and Drug Administration (FDA) and has patent protection into 2037. The pivotal Phase 3 SIERRA (Study of Iomab-B in Elderly relapsed or refractory AML) is a 153-patient, randomized, multi-center clinical trial, studying Iomab-B compared to the control arm of physician's choice of salvage therapy. Control arm options included chemotherapies like cytarabine and daunorubicin and targeted agents such as a Bcl-2 inhibitor (Venetoclax), FLT3 inhibitors and IDH 1/2 inhibitors.

The SIERRA control arm reflects real-world treatment of r/r AML patients with over 20 single agents or combination of agents as no standard of care exists for this patient population. Data from full patient enrollment presented at the Transplantation & Cellular Therapy Tandem Meetings in April 2022 showed that 100% of patients receiving Iomab-B accessed BMT and engrafted without delay. Iomab-B was also shown to be well tolerated given its targeted nature, consistent with its previous clinical data.

The SIERRA trial enrolled patients at 24 leading transplant centers in the United States and Canada that perform over 30% of AML BMTs. Developed at the Fred Hutchinson Cancer Research Center, a pioneer in the field of BMT, Iomab-B is supported by data in six disease indications including leukemias, lymphomas and multiple myeloma, which afflict over 100,000 patients annually. Actinium intends to pursue additional indications for Iomab-B beyond AML.

Actinium also intends to pursue international regulatory approvals independently and through partnerships. In April 2022, Actinium licensed the European, Middle East and North African commercial rights for Iomab-B to Immedica AB, a fully-fledged independent pharmaceutical company headquartered in Sweden. In exchange, Actinium received an upfront payment of $35 million USD with the potential for an additional $417 million USD in regulatory and sales milestones and mid-twenty percent royalties.

Europe represents a commercial opportunity double the size of the United States by number of patients with AML receiving BMT. Iomab-B has been granted Orphan Drug Designation by the European Medicines Agency (EMA) and has received positive Scientific Advice from the Committee for Medicinal Products for Human Use (CHMP) of the EMA indicating that the Phase 3 SIERRA trial design, primary endpoint and planned statistical analysis are acceptable as the basis for a Marketing Authorization Application.