Oncology Experts Review Initial Patient Outcomes From Ongoing Actimab-A Phase I/II Clinical Trial

NEW YORK, NY -- (Marketwired) -- 06/04/15 -- Actinium Pharmaceuticals, Inc. (NYSE MKT: ATNM) ("Actinium" or "the Company"), a biopharmaceutical Company developing innovative targeted payload immunotherapeutics for the treatment of advanced cancers, announced that the presentation of poster and abstract at ASCO 2015, the 51^stAnnual Meeting of American Society of Clinical Oncology, was given in Chicago on May 31. Data from the Company's ongoing multi-center Phase 1/2 Study for Actimab-A for the treatment of newly diagnosed Acute Myeloid Leukemia (AML) in elderly patients were presented by Dr. Joseph Jurcic of Columbia University Medical Center, Actinium's Clinical Advisory Board Chairman.

Among the first 12 patients treated at increasing dose levels, two Actimab-A treated patients achieved complete remission with different degrees of hematological recovery (CRi) and one patient achieved complete remission with incomplete platelet count recovery (CRp), for a combined overall response rate of 25% among all patients and 67% among patients treated at the highest dose level to date. Patients ranged from 68 to 87 years of age, all with high- or intermediate-risk cytogenetics; half of them had prior MDS therapy. Dose limiting toxicities were limited to one patient with prolonged myelosuppression. No extramedullary dose limiting toxicities were observed. Patients had high pre-treatment leukemia burdens of up to 88% in the bone marrow, and half had blast reductions >50% after Actimab-A treatment. The Company also recently began the fourth and last cohort (2.0 μCi/kg per dose) in the Phase I portion of this trial.

"These results generated significant interest and were well received by the oncology experts," said Dr. Joseph Jurcic, the presenter and lead author of the poster and abstract. "Oncologists were particularly excited to see objective responses in patients who already received best available therapy for their prior blood cancer."

Summary of the presented data can be found in the ASCO Abstract #7050 titled "Phase I trial of α-particle therapy with actinium-225 (225Ac)-lintuzumab (anti-CD33) and low-dose cytarabine (LDAC) in older patients with untreated acute myeloid leukemia (AML)."

Dr. Jurcic is Director of the Hematologic Malignancies Section of the Hematology/Oncology Division and Professor of Clinical Medicine at Columbia University Medical Center. He is a hematologist/oncologist focusing on the treatment of acute and chronic leukemias, myeloproliferative neoplasms, and myelodysplastic syndrome. His research interests include acute myeloid leukemia, radioimmunotherapy with alpha and beta particle-emitting radioisotopes, monoclonal antibody therapy for leukemia, development of novel small molecule inhibitors for leukemia and molecular monitoring of minimal residual disease. He is the primary investigator for the current Actimab-A clinical trial and Clinical Advisory Board Chairman. He received his medical degree from the University of Pennsylvania and completed his fellowship in Hematology-Oncology at Memorial Sloan-Kettering Cancer Center.

About Actimab-A
Actimab-A is a radiolabeled antibody being developed for newly diagnosed AML in patients over 60, and is currently in a multicenter Phase 1/2 clinical trial. Based on Actinium's alpha-particle immunotherapy (APIT) platform, Actimab-A consists of the CD33 antibody lintuzumab linked to the actinium-225 payload. Actimab-A has attracted support from leading experts at the prestigious and high-volume cancer treatment hospitals due to the potential of its safety and efficacy profile, as well as its potential potency, specificity and ease of use. Clinical trials are being conducted at world-class cancer institutions such as Memorial Sloan Kettering Cancer Center, MD Anderson Cancer Center, Johns Hopkins Medicine, Columbia University Medical Center, University of Pennsylvania Health System, Fred Hutchinson Cancer Research Center, and the Texas Oncology-Baylor Charles A. Sammons Cancer Center. Actimab candidates are in early development for other cancers.

About Iomab-B
Iomab-B™ is being developed to prepare patients for hematopoietic stem cell transplantation (HSCT) and will enter a single, pivotal Phase 3 clinical study in relapsed/refractory AML. Iomab-B is a radioimmunoconjugate consisting of BC8, a novel murine monoclonal antibody, and iodine-131 radioisotope. BC8 has been developed by Fred Hutchinson Cancer Research Center to target CD45, a pan-leukocytic antigen widely expressed on white blood cells. This antigen makes BC8 potentially useful in targeting white blood cells in preparation for hematopoietic stem cell transplantation in a number of blood cancer indications, including acute myeloid leukemia (AML), chronic myeloid leukemia (CML), acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), Hodgkin's disease (HD), Non-Hodgkin lymphomas (NHL) and multiple myeloma (MM).

About Actinium Pharmaceuticals
Actinium Pharmaceuticals, Inc. (www.actiniumpharma.com) is a New York-based biopharmaceutical company developing innovative targeted payload immunotherapeutics for the treatment of advanced cancers. Actinium's targeted radiotherapy products are based on its proprietary delivery platform for the therapeutic utilization of alpha-emitting actinium-225 and bismuth-213 and certain beta emitting radiopharmaceuticals in conjunction with monoclonal antibodies. The Company's lead radiopharmaceutical product candidate Iomab-B is designed to be used, upon approval, in preparing patients for hematopoietic stem cell transplant, commonly referred to as bone marrow transplant. The Company plans to conduct a single, pivotal, multicenter Phase 3 clinical study of Iomab-B in refractory and relapsed AML patients over the age of 55 with a primary endpoint of durable complete remission. The Company's second product candidate, Actimab-A, is continuing its clinical development in a Phase 1/2 trial for newly diagnosed AML patients over the age of 60 in a single-arm multicenter trial.

Forward-Looking Statement for Actinium Pharmaceuticals, Inc.
This news release contains "forward-looking statements" as defined in the Private Securities Litigation Reform Act of 1995. These statements are based on management's current expectations and involve risks and uncertainties, which may cause actual results to differ materially from those set forth in the statements. The forward-looking statements may include statements regarding product development, product potential, or financial performance. No forward-looking statement can be guaranteed and actual results may differ materially from those projected. Actinium Pharmaceuticals undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events, or otherwise.

Contact:
David Gould, MD
SVP, Finance and Corporate Development
Actinium Pharmaceuticals, Inc.
dgould@actiniumpharma.com

Source: Actinium Pharmaceuticals

Released June 4, 2015