[Treatment of polycythemia vera with hydroxyurea or pipobroman. Efficacy and toxicity analysed from a protocol of 96 patients under 65 years of age. Le Groupe d'Etude des Polyglobulies].
Between 1980 and 1991, 96 patients with documented polycythemia vera were treated by hydroxyurea or pipobroman, according to a protocol including randomization, and maintenance therapy. Complete remission was induced in all cases. Two cases treated with hydroxy-urea had a very severe granulothrombocytopenia during the initial phase. Maintenance was generally satisfactory on pipobroman, but the platelet count often remained high (400 to 900.10(9)/l) on low-dosage hydroxy-urea, with a risk of vascular events. Progressive resistance to these drugs was observed in 5 cases. Digestive and cutaneous troubles were more frequent on pipobroman maintenance, sometimes enough to legitimate a therapeutic change. It may be concluded that such a treatment is less easy to use and to follow than is currently accepted. In the present series (397/years/patients follow-up, median 5-3 years), only one leukemia and one cancer were observed, which however only demonstrates the absence of any carcinogenic risk at short- but not at long-term.