A phase II trial of pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone), a novel anti-fibrosing agent, in myelofibrosis with myeloid metaplasia.

The anti-fibrotic and cytokine modulatory properties of pirfenidone suggest its usefulness in the treatment of myelofibrosis with myeloid metaplasia (MMM). In a prospective study, 28 patients with MMM were treated with oral pirfenidone. Twelve patients completed 1 year of therapy; 13 were withdrawn because of disease progression and three because of drug intolerance. Only one patient experienced a clinically relevant benefit with respect to anaemia and splenomegaly. The overall lack of clinical benefit correlated with no significant improvement in the bone marrow morphological features of the disease. We conclude that pirfenidone has no significant clinical or biological activity in MMM.