Inhibitor may fulfill unmet need in MF

In the ITT population, 24.5% of pacritinib-treated patients and 6.5% of BAT-treated patients had a 50% or greater reduction in TSS score (P<0.0001). In the evaluable population, 40.9% and 9.9% of patients, respectively (P<0.0001), met this endpoint.

Dr Mesa also pointed out that 25.7% of pacritinib-treated patients who were severely anemic and transfusion-dependent—requiring at least 6 units of blood in the 90 days prior to study entry—became transfusion independent. But none of the BAT-treated patients did so (P<0.043).

Adverse events

“The most common adverse events [in the pacritinib arm] were consistent with the earlier studies,” Dr Mesa said. “Gastrointestinal toxicities were most common, although typically at low grades.”

“As expected, we saw very few individuals with any significant thrombocytopenia or anemia as drug-emergent. There were individuals who enrolled in the study as a grade 4, so some of those remained.”

The most common adverse events of any grade were diarrhea (53.2% in the pacritinib arm and 12.3% in the BAT arm), nausea (26.8% vs 6.6%), anemia (22.3% vs 19.8%), thrombocytopenia (16.8% vs 13.2%), and vomiting (15.9% vs 5.7%).

Ten percent of patients in the pacritinib arm required dose reductions due to adverse events. Diarrhea prompted dose interruptions in 13 patients and discontinuation in 3 patients. But pacritinib-associated diarrhea typically resolved in a little over a week.

“Based on these preliminary results, pacritinib may represent a very important agent for individuals with advanced disease and may have an impact on the disease course,” Dr Mesa concluded.