Helsinn and MEI begin dosing in Phase II combination trial to treat MDS


Swiss pharmaceutical group Helsinn and US-based oncology firm MEI Pharma have begun dosing patients in a Phase II clinical trial of pracinostat and azacitidine combination for the treatment of patients with myelodysplastic syndromes (MDS).

Pracinostat is MEI Pharma’s investigational oral histone deacetylase (HDAC) inhibitor, while aazacitidine is a chemical analog of a nucleoside called cytidine.

The dose-optimisation, two-stage Phase II trial will assess the tolerability and efficacy of the combination in higher risk MDS patients who did not receive any prior treatment with hypomethylating agents (HMAs).

Designed to enrol approximately 120 patients at around 25 centres, the trial will investigate the combination of 45mg pracinostat with standard dose of azacitidine.

The trial is set to examine if the reduced pracinostat dose, when compared to previous trials, has the ability to improve the tolerance of the combination, as well as obtain a clinically meaningful improvement in efficacy.

"Based on our clinical experience with the combination, we believe that a reduced dose of pracinostat has the potential to improve tolerability in patients with higher risk MDS, thereby improving efficacy of the combination compared to azacitidine alone."

MEI Pharma chief medical officer Robert Mass said: "Based on our clinical experience with the combination, we believe that a reduced dose of pracinostat has the potential to improve tolerability in patients with higher risk MDS, thereby improving efficacy of the combination compared to azacitidine alone.”

The open-label, single arm first stage of the trial will evaluate if the lower pracinostat dose in around 40 patients will result in a discontinuation rate that approximates the rate previously observed with azacitidine alone.

Based on the results from the first stage, the randomised and placebo-controlled second stage will confirm the discontinuation rate in a blinded setting and will assess the safety and efficacy.

The results from the trial’s first stage are expected to be reported in the first quarter of next year.

In August last year, Helsinn and MEI Pharma signed an exclusive licence, development and commercialisation agreement for pracinostat in AML, MDS and other potential indications.