On October 28, 2020 Actinium Pharmaceuticals, Inc. (NYSE AMERICAN: ATNM) ("Actinium" or the "Company") reported a corporate update covering the progress made in 2020 thus far as well as major milestones expected by year-end and in 2021 (Press release, Actinium Pharmaceuticals, OCT 28, 2020, View Source [SID1234569245]).
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Sandesh Seth, Actinium’s Chairman and Chief Executive Officer, said, "We have made material advances in our key clinical trials and programs for targeted conditioning and therapeutic combinations this year and anticipate several important milestones before year-end and in 2021. Collectively, as described in our recent shareholder letter, upcoming data events with our Iomab-B SIERRA trial and Actimab-A combination trials will bring into view the opportunity for a much larger and attractive opportunity in R/R AML than either drug candidate alone. Iomab-B, which is in the final quarter of enrollment of the Phase 3 SIERRA trial for targeted conditioning of older patients with R/R AML, has the potential to make potentially curative BMT accessible for patients not able to receive BMT with today’s conditioning approaches. Our CD33 program is focused on enhancing patient outcomes by leveraging the potentiating or mechanistic synergy of targeted radiation via our Antibody Radiation Conjugates (ARCs) with other therapeutic modalities.
"We have also made great strides with our Iomab-ACT program for targeted conditioning for the large and growing fields of cell and gene therapies with our recent collaboration with Memorial Sloan Kettering and their CD19 CAR-T therapy that has been awarded an NIH STTR Fast-Track Phase 1/2 grant. Armed with a highly differentiated technology, a strong balance sheet, enhanced R&D capabilities through our recently acquired research facility and motivated team, we are excited to execute on our vision and for the multiple upcoming clinical milestones that have the potential to transform Actinium."
Key ARC Program Highlights and Outlook:
Iomab-B SIERRA Pivotal Trial
The SIERRA trial reached seventy-five percent enrollment.
In the second quarter, the Company exercised a single ad hoc interim analysis, which was guided by the positive interim results from the first fifty percent of patients enrolled on the pivotal Phase 3 SIERRA trial for Iomab-B that were presented in February 2020 at the Transplant & Cellular Therapy Conference (TCT).
Additionally, the difference in number of patients potentially evaluable for the primary endpoint, measured by 100-day non-relapse transplant related mortality, has remained consistent at roughly 6x greater for the study arm at the 25% and 50% enrollment updates.
The Company will report safety and feasibility data from 75% enrollment in the Fourth Quarter. Additionally, the ad hoc interim analysis to be completed in the Fourth Quarter could result in a recommendation for early termination of the trial for futility of one of the arms, or a continuation of the trial.
Actimab-A and CLAG-M Phase 1 Combination Trial
Successfully completed third and final dose cohort of 1.0 uCi/Kg of Actimab-A marking the completion of the planned Phase 1 trial.
The Company has reported that the second dose cohort demonstrated an 86% complete remission rate in relapsed or refractory AML patients treated with Actimab-A plus CLAG-M, which is a 60% improvement over what is seen with CLAG-M alone. Further, the minimal residual disease or MRD negative rate was 71%, which is an indicator of deep remissions.
The Company expects to present results from the third dosing cohort in the Phase 1 trial in the fourth quarter of 2020.
Actimab-A and Venetoclax Phase 1/2 Combination Trial
Successfully completed first dosing cohort thus allowing the study to proceed to a second dose cohort of 1.0 uCi/Kg Actimab-A and venetoclax combination.
First in human data expected in 2020; the Company expects to report study proof of concept results in 2021.
Iomab-ACT CAR-T Program
Actinium was awarded a Fast-Track Phase 1/2 STTR grant by the National Institutes of Health (NIH) for a clinical collaboration of Iomab-ACT targeted conditioning with Memorial Sloan Kettering Cancer Center’s (MSK) CD19 CAR T-Cell therapy, 19-28z.
Results published in the New England Journal of Medicine showed an 83% remission rate with MSK’s 19-28z CAR-T utilizing chemotherapy-based conditioning. However, cytokine release syndrome and neurotoxicity were cited as a challenge for further development in the study which included patients with relapsed or refractory B-cell acute lymphoblastic leukemia.
Preclinical data supporting Iomab-ACT’s application in targeted lymphodepletion prior to ACT such as CAR-T was published in the journal Oncotarget. These results support the application of CD45-targeted radioimmunotherapy lymphodepletion with a non-myeloablative dose of Iomab-ACT prior to adoptive cell therapy.
The Company expects Phase 1 proof of concept data from collaboration in 2021.
Research Facility and Expanded R&D Capabilities
Launched R&D Lab with a focus on applying its Antibody Warhead Enabling (AWE) technology platform and scientific expertise in radioimmunobiology to the development of ARCs. The Company intends to leverage the new facility to better evaluate new assets for in-licensing, broaden potential uses of its clinical stage candidates and to secure collaborations and partnerships with biopharmaceutical companies.
Financial Condition
Actinium reported a cash balance of $48.2 million as of September 30, 2020 compared with $9.2 million as of December 31, 2019 and a net loss of $5.5 million for 3Q:2020. Based on current estimates, the current cash balance is expected to fund operations through clinical milestones including completion of the Pivotal Phase 3 SIERRA trial, completion of ongoing Phase 1/2 Actimab-A combination trials and planned R&D activity.