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Table 2 Dose-limiting toxicities in phase 1 (n = 43)

From: Phase 1/2 study of pacritinib, a next generation JAK2/FLT3 inhibitor, in myelofibrosis or other myeloid malignancies

Pacitinib dose cohort Patients, n DLTs in first cycle
N (%) Description Outcome
100 mg 3 0   
150 mg 6 1 (16.7) Grade 3 ECG QT prolonged from days 18–47 Resolved following pacritinib discontinuation.
200 mg 9a 0   
300 mg 6 1 (16.7) Grade 3 diarrhea on days 3–4. Resolved following interruption of pacritinib and treatment with antidiarrheal medication. Pacritinib was restarted.
400 mg 6 0   
500 mg 7 1 (14.3) Grade 2 diarrhea on days 8–140. Resolved following dose reduction to 400 mg and treatment with antidiarrheal medication.
600 mg 6 2 (33.3) Grade 3 diarrhea beginning on day 11. Pacritinib was interrupted then reduced to 400 mg. Antidiarrheal medication was started. Diarrhea was ongoing at the end of treatment.
Grade 1 nausea; grade 1 vomiting; grade 2 dizziness, grade 2 gait disturbance, grade 2 performance status decreased, grade 2 vision blurred Pacritinib was interrupted then reduced to 400 mg. Nausea and vomiting resolved with antiemetic therapy after ~85 days; dizziness resolved after 49 days; performance status decrease resolved after 4 days. Gait disturbance and vision blurred were ongoing at the end of treatment.
  1. aThis cohort included three patients treated with the pacritinib HCl salt formulation and an additional six patients treated with the citrate salt formulation. The two salt forms have been shown to be pharmaceutically equivalent
  2. DLT dose-limiting toxicity, ECG electrocardiogram