Swiss pharmaceutical group Helsinn and US-based MEI Pharma have decided to discontinue the ongoing Phase III clinical trial of pracinostat to treat patients with acute myeloid leukaemia (AML).
The trial was designed to assess the drug in combination with azacitidine in patients not eligible for standard intensive chemotherapy.
Pracinostat is an oral inhibitor of histone deacetylase (HDAC), while azacitidine is a chemical analogue of a nucleoside called cytidine that is found in DNA and RNA.
The randomised, double-blind, placebo-controlled Phase III trial was meant to evaluate the combination therapy in up to 500 patients aged 75 and above.
The primary endpoint of the trial is overall survival, while the secondary endpoints include morphologic complete remission (CR) rate, event free survival (EFS), and duration of CR.
An interim futility analysis by the Independent Data Monitoring Committee (IDMC) has found that the study was not likely to meet the primary endpoint when compared to the control group.
Based on these interim analysis findings, the companies decided to discontinue the enrolment of patients and end the study.
Helsinn and MEI Pharma said in a statement: “The decision was based on a lack of efficacy and not on safety concerns. Pending further evaluation, patients currently enrolled in other pracinostat studies will continue treatment.”
Pracinostat is also undergoing a Phase II trial for the treatment of patients with high or very high-risk myelodysplastic syndromes (MDS).
The combination of the drug with azacitidine to treat newly diagnosed AML secured orphan drug designation from the US and European regulatory authorities.
Helsinn and MEI Pharma signed an exclusive agreement in August 2016 to licence, develop and commercialise the drug in AML and other potential indications.
Under the terms of the agreement, Helsinn is primarily responsible for development and commercialisation costs.