Actinium Pharmaceuticals, Inc. (NYSE AMERICAN: ATNM) (“Actinium” or the “Company”), a leader in the development of targeted radiotherapies for patients with unmet needs, today announced that the Phase 1 trial studying Actimab-A with the salvage chemotherapy CLAG-M in patients with relapsed or refractory acute myeloid leukemia (r/r AML) who are fit for intensive therapy has completed the planned dose escalation and patient enrollment. Patients in the fourth and final dose escalation cohort received 1.0 μCi/kg of Actimab-A with the standard CLAG-M dose regimen.
This novel combination trial is being conducted at the Medical College of Wisconsin. Updated Phase 1 data is expected will be presented at the American Society of Hematology (ASH) Annual Meeting in December and Actinium expects to provide an update on the future clinical development of this combination by year end.
Actimab-A CLAG-M combination data was presented at ASH 2020 from the first three dose cohorts, which highlighted:
- 100% remission rate (CR/CRi) in patients receiving 0.75 μCi/kg of Actimab-A with CLAG-M
- 83% remission rate in patients who received 3 or fewer lines of prior treatment
- 70% of patients achieving a remission were MRD negative
- 67% of patients in the study achieved a remission including patients receiving 0.25 and 0.50 μCi/kg of Actimab-A, which has shown to be subtherapeutic as a single agent in prior studies
- All patients had intermediate (N=5, 33%) or adverse (N=10, 67%) cytogenetics
- Patients had a median of 2 prior therapies (range:1- 5) including prior Venetoclax/HMA (N=7,47%) or bone marrow transplant (N=8, 53%)
These results compare favorably to outcomes with CLAG-M as a single agent, which was shown in a separate study to have a 55% overall response rate and a 39% MRD negativity rate.
Dr. Avinash Desai, Actinium’s Chief Medical Officer, said, “This novel combination has produced promising data with high rates of remission and MRD negativity with an acceptable safety profile thus far. Despite multiple new drug approvals for patients with AML, including several targeted agents, outcomes for patients with relapsed or refractory AML remain poor, especially those with adverse molecular or cytogenetic features. Actimab-A enables the treatment of AML with radiation at a cellular level, which is a novel mechanism not achievable with traditional external beam radiation given the diffuse nature of blood cancers like AML. Given the sensitivity of AML and other blood cancers to radiation, we are optimistic in its potential to improve patient outcomes. We hypothesized that the combination of Actimab-A with CLAG-M would be tolerable given the non-overlapping mechanisms of action and lead to higher and deeper remissions. We have been very pleased with the data from the trial to date and look forward to advancing this novel combination once we have reviewed the data from all dose cohorts, including the data to be presented at ASH in December.”
