Myelofibrosis is characterized by splenomegaly and debilitating constitutional
symptoms that negatively impact patients’ quality of life. ROBUST, a
UK, open-label, phase II study, evaluated the safety and efficacy of ruxolitinib
in patients with myelofibrosis (N = 48), including intermediate-1 risk
patients. The primary composite endpoint was the proportion of patients
achieving treatment success [≥50% reduction in palpable spleen length
and/or a ≥50% decrease in Myelofibrosis Symptom Assessment Form Total
Symptom Score (MF-SAF TSS)] at 48 weeks. This was the first time that
efficacy of ruxolitinib in myelofibrosis has been evaluated based on these
criteria and the first time the MF-SAF was used in a population of patients
solely from the United Kingdom. Overall, 50% of patients and 57% of
intermediate-1 risk patients, achieved treatment success; reductions in
spleen length and symptoms were observed in all risk groups. The majority
of patients (66�7%) experienced ≥50% reductions from baseline in spleen
length at any time. Improvements in MF-SAF TSS were seen in 80�0%,
72�7%, and 72�2% of intermediate-1, intermediate-2, and high-risk patients,
respectively. Consistent with other studies of ruxolitinib, the most common
haematological adverse events were anaemia and thrombocytopenia. Results
indicate that most patients with myelofibrosis, including intermediate-1 risk
patients, may benefit from ruxolitinib treatment.