US-based biopharmaceutical company CTI BioPharma has reported positive top-line results of the Phase III PERSIST-2 trial of pacritinib to treat patients with a high risk of advanced myelofibrosis.

Pacritinib is an investigational, oral kinase inhibitor developed specifically for enzymes such as JAK2, FLT3, IRAK1 and CSF1R.

The JAK enzymes are the integral part in signal transduction pathways, which promotes normal blood cell growth and development, as well as trigger inflammatory cytokine expression and immune responses.

Mutations in these kinases are shown responsible for the outbreak of a variety of blood-related cancers, including myeloproliferative neoplasms, leukaemia and lymphoma.

"These patients represent up to 30% of all myelofibrosis patients and an unmet medical need."

A total of 311 patients were involved in the Phase III PERSIST-2 clinical trial that has been designed as a randomised, controlled study to compare pacritinib with physician-specified best available therapy (BAT) and ruxolitinib to treat myelofibrosis.

Initial results suggested that administration of pacritinib resulted to an improvement in spleen volume reduction (SVR) when compared with the results of BAT and ruxolitinib.

University of Texas MD Anderson Cancer Centre clinical research centre director and principal investigator of PERSIST-2 Phase III study Srdan Verstovsek said: "Unlike patients with myelofibrosis who have normal baseline platelet counts where median survival is reported at 88 months, we recently reported from our institution's experience that patients with severe thrombocytopenia (low platelets) had a median survival of about 14 months.

"These patients represent up to 30% of all myelofibrosis patients and an unmet medical need.

“Data from the PERSIST-2 prospective randomised, controlled trial is encouraging because we need an effective therapy to treat the most challenging patients with low platelet counts we see in our practice."

The previously held PERSIST-1 trial compared pacritinib with BAT, excluding JAK2 inhibitors, to treat primary myelofibrosis, and had also met the primary goal of achieving spleen volume reduction following the administration of pacritinib.