Ruxolitinib Well-Tolerated, Active in Patients with CNL and Atypical CML
Results from a phase 2 clinical trial of patients with chronic neutrophilic leukemia (CNL) or atypical chronic myeloid leukemia (aCML) suggest that ruxolitinib therapy is active and well-tolerated (J Clin Oncol. 2019 Dec 27. Epub ahead of print).
There is currently no approved standard-of-care treatment available for patients with CNL or aCML. Thus, Kim-Hein T. Dao, DO, PhD, Knight Cancer Institute, Oregon Health & Science University, Portland, and colleagues sought to assess the safety and efficacy of ruxolitinib use in this patient population, irrespective of CSF3R mutation status.
A total of 44 patients with CNL (n = 21) or aCML (n = 23) were included in the study, and underwent 6 continuous 28-day treatment cycles. Oncogenic CSF3R mutations were observed in 50% of patients.
The primary end point of the study was overall response rate (ORR), including partial and complete responses, and secondary end points were grade >3 adverse events (AEs), spleen volume, symptom assessment, genetic correlates of response, and rates of survival at 2 years.
Among the first 25 patients enrolled, the ORR was 32%. Across all 44 patients, the ORR was 35%, including 4 complete responses (all CNL) and 11 partial responses (9 CNL and 2 aCML).
No serious AEs were attributed to ruxolitinib therapy, and the most common AEs reported were grade ≥3 anemia in 34% and thrombocytopenia in 14%.
“Ruxolitinib was well tolerated and demonstrated an estimated response rate of 32%,” concluded Dr Dao et al, who also noted that patients with CNL or the CSF3R-T618Imutation were most likely to respond.—Kaitlyn Manasterski
