Long-term outcome of pomalidomide therapy in myelofibrosis

Ninety-four Mayo Clinic patients with myelofibrosis (MF) participated in two consecutive clinical trials of pomalidomide (0.5-3.5 mg/day), with or without prednisone. Overall anemia response was 27% and increased to 53% in JAK2V617F-positive patients with <10 cm palpable splenomegaly and <5% circulating blasts; response rate was 0% in mutation-negative patients with either ≥10 cm splenomegaly or ≥5% circulating blasts (P = 0.0001). Median duration of anemia response was 16 months. Treatment effect on splenomegaly was negligible. To date, pomalidomide therapy has been discontinued in 86 (91%) patients at a rate of 68% at 1 year and 89% at 2 years. Grade 1 sensory neuropathy developed in 4 (13%) of 30 patients treated for ≥1 year. Risk-adjusted survival in pomalidomide-treated primary MF patients (n = 72) was similar to their counterparts not exposed to the drug (n = 471; P = 0.19). Long-term follow-up of pomalidomide treatment in MF reveals palliative value for a select group of patients and treatment-emergent sensory neuropathy.