- Approximately one-third of patients with chronic neutrophilic leukemia (CNL) or atypical chronic myeloid leukemia (aCML) responded to ruxolitinib.
- Patients with CNL or with CSF3R-mutated disease had a greater likelihood of response.
Why this matters
- No standard of care currently exists in this setting.
- Phase 2 study to investigate ruxolitinib in 44 patients (21 with CNL; 23 with aCML).
- Median patient age: 72.9 (range, 43.1-92.3) years.
- 50% of patients had colony-stimulating factor-3 receptor (CSF3R)-mutated disease.
- The study used Simon’s 2-stage "minimax" design to minimize sample size in the event that the study regimen demonstrated low activity.
- Funding: Incyte Corporation.
- 32.0% overall hematologic response rate (ORR) at the end of 6 cycles in the first 25 patients enrolled.
- ORR in the overall cohort of 44 patients:
- 34.9% for all patients.
- 65.0% in patients with CNL.
- 8.7% in patients with aCML.
- Factors associated with increased likelihood of response:
- CNL diagnosis: OR, 19.5 (P<.001>
- CSF3R-mutated disease: OR, 13.722 (P=.002).
- Open-label, single-group study.