NCCN Recommends Pacritinib for Treatment of Myeloproliferative Neoplasms

The National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines have been updated to include pacritinib, a novel oral kinase inhibitor with specificity for Janus associated kinase 2 (JAK2) and interleukin receptor associated kinase 1 (IRAK1), as a recommended treatment for myeloproliferative neoplasms.

“We are grateful that NCCN acted quickly to include [pacritinib] with a Category 2A designation in its Clinical Practice Guidelines in Oncology as a first-line treatment for high-risk patients with myelofibrosis with platelet counts <50 x 109/L who are not candidates for transplant…There is no other FDA-approved first line treatment for these patients with a 2A designation within the NCCN guidelines,” Adam R. Craig, MD, PhD, president and CEO of CTI BioPharma, said in a statement.

In addition, pacritinib was included as a Category 2A designation as second- line treatment for lower-risk and higher-risk patients with myelofibrosis with platelet counts ≥50 x 109/L who are not candidates for transplant.

Pacritinib is an oral kinase inhibitor with activity against JAK2, mutant Jak2 form, and FMS-like tyrosine kinase 3, which contributes to signaling for cytokines and growth factors important to hematopoiesis and immune function. Parcritinib does not inhibit JAK1. Myelofibrosis is associated with dysregulated JAK2 signaling.

A phase 2 trial was conducted in 2020 and determined that pacritinib was best prescribed in 200mg/twice daily doses. No excess of grade 3 or higher hemorrhages or cardiac events occurred in the highest dose group during this trial, although gastrointestinal adverse events, thrombocytopenia, and anemia were the most common adverse effects (AEs).

This treatment is for adults with intermediate or high-risk primary or secondary myelofibrosis. Continued approval for this may rely on verification and description of clinical benefit in a confirmatory trial.

Pacritinib comes with risk of AEs. Serious (11%) and fatal (2%) hemorrhages have occurred in patients with less than 100 platelet counts; serious (13%) and fatal (2%) hemorrhages have occurred in patients with platelet counts of less than 50. Grade 3 bleeding events occurred in 15% of patients compared with 7% in the control.

There were 48% of patients who experienced diarrhea while using pacritinib compared with 15% of patients in the control group. The incidence of reported diarrhea decreased over time from 41% in the first 8 weeks to 8% in the final 8 weeks.

Pacritinib can also cause worsening thrombocytopenia, and prolonged QTc intervals. Other JAK-inhibitors have increased risk of major adverse cardiac events, thrombosis, increased risk of lymphoma and other malignancies, and increased risk of infection.

Coadministration of pacritinib and CYP3A4 inhibitors or inducers is contraindicated.

Reference

NCCN guidelines recommend VONJO (pacritinib) for the treatment of myeloproliferative neoplasms. News Release. CTI Biopharma. April 14, 2022. Accessed April 15, 2022. https://investors.ctibiopharma.com/news-releases/news-release-details/nccn-guidelinesr-recommend-vonjotm-pacritinib-treatment