A best molecular response of at least a 3-log reduction in BCR-ABL mRNA levels predicts better progression-free survival. Kaplan-Meier survival curves are shown for patients achieving a best RQ-PCR level (at any time) above various thresholds. The top panel compares 3 patient groups: those with a best molecular response of at least 3 (log-drop units), at least 2 (but below 3), and below 2. The bottom panel compares patients with a best molecular response of at least 3 versus those below 3. These are landmark analyses starting at the time of CCR.