A PROSPECTIVE COMPARISON BETWEEN TREATMENT WITH PHLEBOTOMY ALONE AND WITH INTERFERON-ALPHA IN PATIENTS WITH POLYCYTHEMIA-VERA

Interferon alpha (alpha-IFN) is increasingly used for the treatment of patients affected by polycythemia vera (PV). As prior studies are dif ficult to interpret in view of the lack of appropriate controls, we un dertook a randomized comparison of lymphoblastoid alpha-IFN (alpha n-1 IFN) treatment against venesection treatment alone. In a crossover tr ial, we treated 22 PV patients alternatively for 5 months each with 3 MU/day sc of alpha n-1 IFN and phlebotomy alone. During IFN treatment, red blood cell count and hematocrit level were well controlled in bot h trial groups, reducing or eliminating the need for phlebotomy in all patients; furthermore, platelet number and white blood cell count dec lined during alpha-IFN therapy. In addition, the number of symptomatic patients was greatly reduced, and in six patients a reduction in sple nic size was observed. Finally, the only patient with chromosomal abno rmalities showed a complete cytogenetic conversion after 5 months of a -IFN therapy. Thus, for the first time, our results provide the unequi vocal demonstration that alpha-IFN is superior to phlebotomy in contro lling the pathologic expansion of erythroid elements and all the clini cal aspects of this disease.