Actinium Announces Two Oral Presentations Featuring Data and Findings from the Phase 3 SIERRA Trial of Iomab-B at the 62nd American Society of…

By daniellenierenberg

NEW YORK, Nov. 4, 2020 /PRNewswire/ --Actinium Pharmaceuticals, Inc.,(NYSE AMERICAN: ATNM) ("Actinium") today announced that two abstracts on the Company's Antibody Radiation Conjugate (ARC) Iomab-B were accepted for oral presentations at the 2020 American Society of Hematology (ASH) annual meeting that is being held virtually December 5-8, 2020.

"This is an exciting fourth quarter for the company and we are honored to have multiple oral presentations at this year's ASH conference. Our 3 oral presentations and one poster presentation demonstrate the clinical progress we have seen not only with Iomab-B, but our other programs including Actimab-A in combination with novel and approved therapeutic agents," stated Sandesh Seth, Actinium's Chairman and CEO. "We look forward to presenting the Iomab-B data in further detail during the two oral presentations on the Iomab-B SIERRA study at ASH in December. The company remains on track to report safety and feasibility data from 75% of the patients to be enrolled in SIERRA, as well as to complete the ad hoc interim analysis in the fourth quarter."

Mark Berger, Actinium's Chief Medical officer, said, "We are encouraged that we continue to see positive ongoing results from our Phase 3 pivotal SIERRA trial in relapsed or refractory Acute Myeloid Leukemia (R/R AML) patients. In the Iomab-B Phase 3 trial we continue to see 100% engraftment in patients receiving a therapeutic dose of Iomab-B in the treatment arm whereas 83% of control arm patients failed salvage therapy, which includes the recently approved targeting agents such as venetoclax. This high failure rate demonstrates the significant need that exists in R/R AML and represents the paradigm shift we are looking to initiate with Iomab-B. The strong safety and feasibility data we have seen thus far gives us confidence that these older patients with active AML may benefit by undergoing a potentially curative bone marrow transplant which they could not receive otherwise."

Details & Highlights for Oral Presentations

Note: The two abstractsincludeSIERRA Phase 3 trial data available to the company from its CRO prior to August 10, 2020, the ASH submission cutoff date. Per ASH rules, updated data sets are permitted to be included in the live presentations.

OralPresentationTitle:

Personalized Targeted Radioimmunotherapy with Anti-CD45 Iodine (131I) Apamistamab [Iomab-B] in Patients with Active Relapsed or Refractory Acute Myeloid Leukemia Results in Successful Donor Hematopoietic Cells Engraftment with the Timing of Engraftment Not Related to the Radiation Dose Delivered

Publication Number:

193

Session Name:

721. Clinical Allogeneic Transplantation: Conditioning Regimens, Engraftment, and Acute Transplant Toxicities

Session Date:

Saturday, December 5, 2020

Presentation Time:

1:00 PM PT / 4:00 PM ET

Phase 3 SIERRA Preliminary Results

Baseline Characteristics

Randomized to Iomab-B(N=53)

Randomized to Conventional Care (CC)(N=53)

Age (yrs, median, range)

64 (55-77)

65 (55-77)

Molecular & Cytogenetic Risk

Favorable: 2%Intermediate: 33%

Adverse: 65%

Favorable: 4%

Intermediate: 30%

Adverse: 66%

% TransplantedIntent-to-Treat Group

87% (46/53)

17% (9/53)

59% (26/44)

Results

Received Therapeutic dose of Iomab-B & Transplanted (N=46)****

Eligible to Receive Std. of Care Transplant Post-Salvage (N=9)

Evaluated for Crossover (N=44)*****

Cross-over Rate

n/a

Received Therapeutic Dose of Iomab-B (N=26)

Transplanted (N=26)

59% (26/44)

% Transplanted

100% (46/46)

17% (9/53)

100% (26/26)

BM Blast % @ baseline (median, range)

26 (4-95)

14 (5-97)

30 (6-87)

BM Blast % pre-HCT (median, range)

26 (4-95)

1 (0-3)*

32.5 (2-75)

Days to ANC Engraftment

14 (9-22)***

17 (13-83)#

14 (10-37)**

Days to Platelet Engraftment

17 (4-39)***

22 (8-35)#

19 (1-38)**

Days to HCT (Post Randomization)

30 (23-60)

66 (51-86)

65 (36-161)^

Myeloablative Dose Delivered to Bone Marrow

14.7 (4.6-32) Gv

n/a

14.4 (6.3-30) Gv

540 (313-1008) mCi

632 (354-1027) mCi

Chimerism>/=95% by D100

91% (39/43^ Evaluable)

67% (4/6^^ Evaluable)

87% (20/23^^^ Evaluable)

100-day non-Relapse Transplant-Related Mortality

5% (2/40 Evaluable)

25% (2/8 Evaluable)

8% (2/24 Evaluable)

*1 pt with 8% BM blasts on D42 with CRp on D50, ** ANC engraftment data not available (N=3), platelet engraftment data not available (N=4); *** ANC engraftment data not available (N=4), platelet engraftment data not available (N=9), ^ 1 patient at 161 days had delayed transplant due to infection and respiratory failure, received Iomab & transplant when stable, # ANC and platelet engraftment data not available (N=2)

**** No Therapy Dose (7) due to: Declining KPS (4), Infusion Reaction (1), Unfavorable Biodistribution (1), Post-Randomization Eligibility (1); 1 Pending Treatment.

*****Ineligible for Iomab-B HCT after crossover evaluation - 13: due to Hospice Care/Progression (4), Declined/Ineligible for HCT (5), Died Pre-Crossover (4). 4 Received Dosimetry but No Therapy Dose due to Declining KPS; 2 Pending Evaluation for Crossover.

^ Did not achieve 95% chimerism (4); Data pending (2); Died (1); ^^ Did not achieve 95% chimerism (4); Data pending (1); ^^^Did not achieve 95% chimerism (4); Data pending (2);

Oral PresentationTitle:

High Doses of Targeted Radiation with Anti-CD45 Iodine (131I) Apamistamab [Iomab-B] Do Not Correlate with Incidence of Mucositis, Febrile Neutropenia or Sepsis in the Prospective, Randomized Phase 3 Sierra Trial for Patients with Relapsed or Refractory Acute Myeloid Leukemia