The European Medicines Agency (EMA) has granted orphan status to Atir, a product consisting of T-cell-depleted donor immune cells, for the treatment of acute myeloid leukemia (AML).
The EMA and the US Food and Drug Administration previously granted Atir orphan status for the prevention of acute graft-vs-host-disease (GVHD) following hematopoietic stem cell transplant (HSCT).
The EMA’s orphan designation provides incentives to support drug development. This includes fee reductions and a 10-year period of market exclusivity in the European Union after product approval.
About Atir
Atir consists of donor immune cells from which the alloreactive T-cells that would otherwise attack the patient’s body have been selectively eliminated.
The product is produced using a molecule known as TH9402 to selectively remove those T cells from the donor graft, while preserving other immune cells. To activate patient-reactive T cells, the graft is mixed (ex vivo) with patient cells.
Then, TH9402 is added. As this phototoxic compound selectively accumulates in activated T cells, the cells can be eliminated by exposing the cell mixture to light of a specific wavelength. The resulting Atir product can be frozen and stored and is infused into the patient in a scheduled procedure.
Trial data
Researchers said Atir proved safe and effective in a phase 1/2 study in which high-risk leukemia patients with very poor prognosis were treated with escalating doses of Atir after a haploidentical HSCT.
The overall survival of 19 patients who received an optimal dose of Atir was 78% at 1 year and 67% at 5 years, rates that compare favorably to outcomes of HSCTs from fully matched donors. The data also suggest that immune cells responsible for the graft-vs-leukemia effect are retained in Atir.
Five-year follow-up data show that none of the 19 patients developed acute grade 3/4 GVHD, compared to an incidence of 30% in matched unrelated HSCTs. In the 9 patients who received an optimal dose of Atir, there was no transplant-related mortality.
Researchers are currently testing Atir in a phase 2 study of patients with AML, acute lymphoblastic leukemia, and myelodysplastic syndrome, to corroborate and extend the safety and efficacy results from the phase 1/2 study. Data from this trial are expected in the second half of 2014.
Atir is under development by Kiadis Pharma. For more information, visit the company’s website.
