Helsinn and Mei Pharma have discontinued the Phase 3 trial that was investigating the safety and efficacy of a combination therapy of pracinostat and Vidaza (azacitidine) in newly-diagnosed patients with acute myeloid leukemia (AML) who were ineligible for high intensity chemotherapy due to advanced age, or other comorbidities.
The decision came after an Independent Data Monitoring Committee completed an interim analysis of the trial (NCT03151408) that indicated the study would likely fail to achieve its main goal of demonstrating the superiority of the combination therapy over Vidaza alone in prolonging patients’ survival.
Based on these findings, the companies decided to stop patient recruitment, which was underway at sites in the U.S., Europe, Australia, and Asia, and to end the study permanently.
The decision was solely based on the lack of efficacy of the combination therapy, as determined by the interim analysis, and not on safety concerns, according to a press release from Helsinn.
For the time being, patients currently enrolled in other trials of pracinostat will continue treatment as planned, while additional analyses are performed.
Pracinostat is an oral investigational inhibitor of the enzyme histone deacetylase (HDAC), which is responsible for chemical modifications that make DNA less accessible to be used for the production of proteins. By blocking the activity of HDAC, pracinostat is thought to help normalize the activity of certain genes that normally inhibit the growth of cancer cells.
The medication, which is being developed under a collaboration established between Helsinn and Mei Pharma in 2016, was being investigated as a potential treatment for newly-diagnosed AML patients, who are unfit for high-intensity chemo, when used in combination with Vidaza.
The combo therapy previously received the designation of orphan drug from the U.S. Food and Drug Administration (FDA) and the European Medicines Agency for this indication, as well as breakthrough therapy from the FDA.
The combo therapy is being tested in patients with high or very high risk myelodysplastic syndrome, another type of blood cancer, in a Phase 2 trial (NCT03151304) currently underway at several sites across the U.S.