Individualizing Treatment Approaches in MPN - Episode 13

A Review of Pacritinib and PACIFICA Data

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Srdan Verstovsek, MD, PhD, briefly reviews the role of pacritinib in patients with myelofibrosis as well as the PACIFICA study.

Srdan Verstovsek, MD, PhD: Although we have 2 JAK inhibitors approved, ruxolitinib and fedratinib, they are not suggested to be given to patients with low platelets, below 50,000 per mm3. This is because they can worsen the thrombocytopenia and possibly cause some bleeding. The guidelines are to be careful. And ruxolitinib in patients who have platelets between 50,000 and 100,000 per mm3 is given at a lower dose. Fedratinib does not need that adjustment in the dose. It can be given relatively safely in this patient group. However, when we get to the patients with platelets below 50,000 per mm3, we are in trouble. Pacritinib is nonmyelosuppressive JAK inhibitor that has been in clinical studies for several years. It is effective, to a degree, in patients with low platelets. It does not lower the blood cell count much. It has some toxicity on the GI [gastrointestinal] part, with some nausea, vomiting, and diarrhea, which one can control with supportive-care measures. This is because it inhibits the FLT3. FLT3 inhibitors cause some nausea, vomiting, and diarrhea. But that combination with nonmyelosuppressive agent that is relatively safe to give has, as we talk about the PACIFICA study, a possible role in everyday management of patients with such low platelets.

PACIFICA is a randomized study between pacritinib on 1 hand in 1 arm and the best-available therapy on the other hand. That would be the other arm, and one can use anything. It’s the best-available therapy, whatever the doctor wants to do. There is not much you can do, so pacritinib, if it’s successful in the PACIFICA study, would have a major impact on what we do in this unfortunate patient with low numbers, low platelet numbers. We can’t really give them an effective dose of ruxolitinib or fedratinib, and in the frontline and first line, or in the second line, pacritinib will have a significant role.

Transcript edited for clarity.