Levy, R.

7083 Background: Patients with Myelofibrosis (MF) suffer from significant fatigue, constitutional symptoms and splenomegaly (Mesa et. al. Cancer 2007) not improved by current therapy. The 6MWT measures functional status in cardio-pulmonary clinical trials. We undertook a prospective feasibility study of the 6MWT in MF patients for use in therapeutic clinical trials. Methods: MF patients (able to walk, normal vitals, not on a JAK2 inhibitor) were eligible. Baseline features and the MF symptom assessment form (MFSAF: Mesa et. al. Blood 2008) was administered. The 6MWT was administered in standardized fashion (American Thoracic Society: observed laps of a 30 - 35 meter long course, indoors, level, without encouragement), and then repeated for further validation. Results: Safety of the 6MWT: Fifty five MF patients were enrolled with only 2 patients (3%) stopping the 6MWT early secondary to fatigue. There were no adverse events attributable to undergoing the 6MWT in test subjects. Results of the 6MWT: Current results of our ongoing study demonstrate compared to age matched healthy volunteer controls, males with MF walk approximately 90 meters less and females with MF walk approximately 60 meters less (Table). Correlation of 6MWT Results to Patient Reported Symptoms (MFSAF): Results from the MFSAF demonstrated the fatigue (as assessed by the brief fatigue inventory (Medoza et. al. Cancer 1999) embedded in the MFSAF) showed patients with a higher BFI (i.e., more fatigued) had more impairment in the 6MWT than those with low BFI scores. Symptomatic burden as assessed by the MFSAF were typical for MF, correlation of individual symptom severity with 6MWT will require a larger trial for adequate power. Conclusions: The 6MWT can be safely performed in un-selected MF patients, and demonstrates a functional deficit compared to published controls. Validation of the ability of the 6MWT to measure functional improvements in MF patients as a response to novel therapy trials is planned. [Table: see text] No significant financial relationships to disclose.