NCT03165734

A Phase 3 Study of Pacritinib in Patients With Primary Myelofibrosis, Post Polycythemia Vera Myelofibrosis, or Post-Essential Thrombocythemia Myelofibrosis

A Randomized, Controlled Phase 3 Study of Pacritinib Versus Physician's Choice in Patients With Primary Myelofibrosis, Post Polycythemia Vera Myelofibrosis, or Post-Essential Thrombocythemia Myelofibrosis With Severe Thrombocytopenia (Platelet Count <50,000/μL)(PACIFICA)

• Status: Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 399 (estimated)
• Sponsor: Swedish Orphan Biovitrum · Industry
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

This study (study ID PAC203 North America; PAC303 ex-North America) is evaluating 200 mg BID of pacritinib compared to physician's choice (P/C) therapy in patients with MF and severe thrombocytopenia (platelet count \<50,000/μL). Approximately 399 patients in total will be enrolled, randomized 2:1 to either pacritinib (approximately 266 patients) or to P/C therapy (approximately 133 patients) Condition or disease: Primary Myelofibrosis/Post-Polycythemia Vera Myelofibrosis/ Post-essential Thrombocythemia Myelofibrosis Intervention/treatment: Drug-Pacritinib

Detailed description

The study is a randomized, controlled phase 3 study comparing the efficacy of pacritinib with P/C therapy in patients with PMF, PPV-MF, or PET-MF (Dynamic International Prognostic Scoring System \[DIPSS\] risk score of Intermediate-1 to High-Risk), who have had had no or limited exposure to any JAK2 inhibitor or are JAK2 inhibitor-naive, and who have severe thrombocytopenia (platelet count \<50,000/µL). This study was designed to use the pacritinib 200 mg BID dose, which was determined to be the optimal dose based on dose- and exposure-response analyses conducted using all available data, including the dosing data from the previous portion of this study. Patients will be randomized 2:1 to receive pacritinib 200 mg BID or the P/C therapy (limited to single drugs from the following list: corticosteroids, hydroxyurea, danazol, or low-dose ruxolitinib). The proposed P/C regimen for a patient must be selected prior to randomization. Randomization will be stratified by prior JAK2 inhibitor therapy (yes/no) and P/C therapy selected prior to randomization. Prior JAK2 inhibitor therapy will be defined as any duration of treatment with a JAK2 inhibitor, such as ruxolitinib, fedratinib, or momelotinib. To be eligible, patients are not allowed to have been treated with more than one JAK2 inhibitor. Assigned treatment will continue until the patient experiences progressive disease or intolerable AEs, withdraws consent, or initiates new MF-directed therapy. No study treatment crossover will be allowed at any time. All patients should complete all visit procedures through Week 24, including patients who stop treatment or have protocol-defined progressive disease prior to Week 24, unless the patient withdraws consent for study procedures, dies, undergoes splenic irradiation or splenectomy, initiates any non-protocol-directed anti-MF treatment, or the study is terminated. In addition to the above, patients will be considered to have discontinued treatment if pacritinib or P/C therapy is held for \>28 consecutive days due to treatment toxicity, or if treatment is discontinued for lack of efficacy, or at the request of the principal investigator or the patient. Following the Week 24 assessment, patients who are benefiting from therapy will be allowed to continue receiving the assigned treatment (pacritinib or P/C) until the patient experiences progressive disease, intolerable AEs, withdraws consent, or initiates new MF-directed therapy. All randomized patients will be followed for survival for 2.5 years from the date of randomization unless consent for follow-up is withdrawn.

Conditions

• Primary Myelofibrosis
• Post-polycythemia Vera Myelofibrosis
• Post-essential Thrombocythemia Myelofibrosis

Interventions

Type	Name	Description
DRUG	Pacritinib	Oral administration. Supplied in capsules containing 100 mg (as the free base) in red cap/gray body size 0 opaque hard gelatin capsules. The inactive ingredients are microcrystalline cellulose, magnesium stearate, and polyethylene glycol 8000. Each capsule contains 146 mg of pacritinib citrate, which is equivalent to 100 mg pacritinib free base
DRUG	Physician's Choice medications	Physician's Choice medications will be selected and administered according to the investigator's judgement. Investigators can select individual P/C agents but cannot combine agents or give them sequentially.

Timeline

• Start date: 2017-06-26
• Primary completion: 2026-12-31
• Completion: 2027-07-30
• First posted: 2017-05-24
• Last updated: 2026-02-25

Locations

207 sites across 24 countries: United States, Australia, Belarus, Bosnia and Herzegovina, Brazil, Bulgaria, Canada, Czechia, France, Georgia, Hungary, India, Israel, Italy, Japan, Kazakhstan, Poland, Romania, Russia, Serbia, South Korea, Spain, Ukraine, United Kingdom

Regulatory

• FDA-regulated drug study