The Seattle, US based biotech announced the halt this week, explaining that it received an oral communication from the FDA followed by a letter confirming the IND for pacritinib has been placed on full clinical hold.
CTI BioPharma also said it has withdrawn its New Drug Application (NDA) for the drug until it "has had a chance to review the safety and efficacy data."
The firm added that: "Under the full clinical hold, all patients currently on pacritinib must discontinue pacritinib immediately and no patients can be enrolled or start pacritinib as initial or crossover treatment.
"All clinical investigators worldwide have been delivered a notice of the full clinical hold."
According to CTI the FDA imposed a partial hold on the study on February 4 in response to "excess mortality and other adverse events in pacritinib-treated patients."
Global trial
The Phase III study - known as PERSIST-2 - is examining whether "once-daily or twice-daily pacritinib results in a greater proportion of patients with thrombocytopenia and myelofibrosis achieving ≥ 35% reduction in spleen volume from baseline."
The drug is being tested at sites in the US, Australia, Belgium, Canada, the Czech Republic, France, Germany, Hungary, The Netherlands, New Zealand, Russia and the UK. It has enrolled an estimated 300 people according to the latest information on US trial registry, clinicatrials.gov.
CTI BioPharma is planning to commercialize pacritinib with Baxalta - previously known as Baxter International - which licensed rights to the drug in 2013 for $60m upfront and an agreement to pay milestones of up to $112m.
Products
At present the Seattle biotech's only approved product is a drug called Pixuvri (pixantrone) that was cleared to treat aggressive B-cell non-Hodgkin lymphoma (NHL) by European authorities 2012.
French drugmaker Servier licensed commercialisation rights to pixantrone in September 2014 for an upfront payment of $18.1m (€14m).
Under the deal Servier has the right to commercialize the drug in all countries except Austria, Denmark, Finland, Germany, Israel, Norway, Sweden, Turkey, the UK and the US. In addition to the upfront payment, the France drugmaker also pays royalties on sales.