Dynamic of morphologic and molecular remission in patients (pts) with APL treated with frontline ATRA and arsenic trioxide (ATO).

6548 Background: APL is associated almost in all pts with t (15; 17) (q21; q22) leading to the fusion gene PML-RARα which can be identified by reverse transcriptase polymerase chain reaction (RT-PCR). Minimal residual disease (MRD) monitoring based on the detection of PML-RARα transcripts by PCR technology has a well-demonstrated role in APL. Purpose: To describe the dynamics of response in pts with APL on our frontline study of ATRA and ATO. Methods: From February 2002 to January 2010, 111 pts with newly diagnosed APL have been treated with ATRA plus ATO. The first cohort of 65 pts received ATRA and ATO (beginning on day 10 of ATRA). High risk pts (WBC > 10 x 109/L) received GO (gemtuzumab) on the first day. The second cohort of 46 pts (38 evaluable pts) received ATRA and ATO concomitantly on day one. They also received GO on day one, if high risk, and if their WBC increased to more than 30 x 109/L during induction. Quantitative PCR (Q-PCR) for PML-RARα fusion gene was conducted after induction and throu...