Treatment of polycythemia. II - Randomized protocol in polycythemia vera patients comparing hydroxyurea and pipobroman.

Aims. - To compare by a prospective study in low risk polycythemia vera (PV) patients alone two drugs: hydroxyurea and pipobroman. Toxicity, efficiency, and leukemogenic potential were studied. Patients. - 294 patients with a documented PV, aged less than 65 years, have been included since 1980 in a prospective study comparing hydroxyurea and pipobroman. Blood cell counts were performed every two months and a clinical evaluation by a specialist was obtained every four or six months. Results. - Hematologic toxicity of both drugs was higher than expected, requiring strict surveillance. These drugs were tolerated in some (gastric pain and diarrhea on pipobroman, buccal aphtosis and chronic leg ulcers on hydroxyurea), leading to a change of arm in 10 % of the cases, Hydroxyurea did not control the mega-karyocitic hyperplasia in 40 % of the cases, which probably explains a high rate of progression to myelofibrosis,vith myeloid metaplasia in this arm. Both drugs were leukemogenic with an actuarial risk of about 15 % at the 15 th gear, not significantly lower than that observed in the P-32 treated patients, A significant risk of cutaneous malignancy was observed in the hydroxyurea arm. The mean expectancy of life cannot get be accurately evaluated, but seems significantly lower than that of the reference population. Conclusion. - The treatment of PV by hydroxyurea or pipobroman has to account for these results less optimistic than those traditionally well-known to hematologists and internists.