ALL Transretinoic Acid Followed by Intensive Chemotherapy in Newly Diagnosed Acute Promyelocytic Leukemia: A Pilot Study on 27 Cases

Abstract

Anthracyc1ine (or its derivatives) and cytosine arabinoside (Ara C) combinations give complete remission (CR), in 70 to 75% of cases of acute promyelocytic leukemia (APL) and 35 to 40% of patients achieving CR are cured with adequate consolidation therapy [1–5]. However, 25 to 30% of the patients failure to achieve CR, because of death due to DIC, or sepsis during the chemotherapy induced period of aplasia rather than because of true leukemic resistance, which is rare in APL. All transretinoic acid (ATRA) has selective in vitro and in vivo differentiating activity on abnormal promyelocytes in APL and is capable of inducing a high CR rate in newly diagnosed and relapsing APL [6–11]. Treatment with ATRA leads to rapid improvement of DIC, without any phase of aplasia, suggesting that ATRA may reduce the 2 main causes of failure to achieve CR with chemotherapy in APL. However, ATRA may be associated to rapidly developing hyperleucocytosis, leading to life threatening leucostasis [15–18] and patients who achieve CR with ATRA and are maintained on ATRA alone usually rapidly relapse. This lead us to start a pilot phase of A TRA followed by intensive chemotherapy in newly diagnosed APL. The purpose of intensive chemotherapy was to reduce leukocyte counts in patients with rapidly developing hyperleukocyfosis and to prolong remission duration in all cases.