Monday, Actinium Pharmaceuticals released promising results Monday from a Phase III trial studying its lead radiotherapy candidate, Iomab-B, for patients with relapsed or refractory AML.
Actinium Pharmaceuticals released promising results Monday from a Phase III trial studying its lead radiotherapy candidate, Iomab-B, for patients with relapsed or refractory acute myeloid leukemia.
The SIERRA trial utilized Iomab-B as a conditioning regimen designed to help patients qualify for a bone marrow transplant, a potentially curative treatment for AML.
With a statistical significance value of p<0.0001, 100% of the patients receiving Actinium’s first-in-class radiotherapy were able to receive a bone marrow transplant, with engraftment occurring without delay.
In the control arm, 82% of patients failed to achieve durable complete remission. Many from this arm were able to cross over to receive Iomab-B treatment.
Bone marrow transplants typically become an option when the patient is considered in remission. A transplant can then prevent a relapse. Once the leukemia is relapsed/refractory, the prognosis is poor and treatment challenging.
In the over-55 group, it is difficult to get the patient into remission with traditional chemotherapies and radiation, yet this is the prime candidate needing treatment, as the median age for AML diagnosis is 68. Once AML has relapsed, a transplant is likely the patient’s only option.
Many biotech companies developing radiotherapy treatments are working toward conditioning, targeting patients that are in remission. Actinium’s Iomab-B stands out as a targeted radiotherapy, zeroed in on CD45 cell expression to both induce remission and condition the body for the bone marrow transplant to take place successfully.
“It’s certainly exciting to get these results with that P value,” said Sandesh Seth, Actinium CEO, in an interview with BioSpace.
“Presuming the drug is approved at some point, this would be a paradigm change for patients and how many of them, who live maybe a few months today, can access a bone marrow transplant and have long-term survival,” he continued.
What’s Behind and Ahead
Actinium has never had more than 30 people on staff but the company is poised for growth to take that next step – a BLA submission to the FDA.
Three additions to the leadership team were announced along with multiple other junior positions. Seth also hinted at bringing on “somebody from big pharma who is a very senior person,” but wasn’t ready to name names ahead of the official announcement.
Not wanting to put up any projections for coming growth, he made it clear the company would be scaling up to the opportunity.
Having moved past previous CMC issues, Actinium plans to continue manufacturing Iomab-B itself. Seth said it’s less complex than the CAR-T manufacturing process, although shelf life is crucial due to the radiation as the drug essentially starts eating itself after five to 10 days. The plan is to continue with the current ecosystem as the therapy moves forward.
The SIERRA trial design was selected by the FDA with 20 different regimens in the control arm. Seth believes the trial’s results warrant an early access program. Both the FDA and EMA have granted the Orphan Drug Designation to Iomab-B.
Actinium will submit a BLA for the radiotherapy in 2023 with hopes for a 2024 approval. In the meantime, the company has enough cash on hand to take operations into 2025.
Also high on the company’s list of priorities is its second product candidate targeting CD33, another marker for AML. Actimab-A is also in studies for relapsed/refractory AML as a therapeutic to be used in combination with a chemo regimen.
Seth said he is excited about this program as well and hopes that having both of these tools - a therapeutic and a conditioning drug for transplant - in the arsenal will offer AML patients a chance at longer-term survival.
