An analysis of the impact of CD56 expression in de novo acute promyelocytic leukemia patients treated with upfront all-trans retinoic acid and anthracycline-based regimens.

Out of 956, there were 95 (10%) CD56+ APL patients treated with PETHEMA ATRA and chemotherapy. CD56+ expression was associated with high WBC, BCR3 isoform, and co-expression of CD2, CD34, CD7, HLA-DR, CD15, and CD117 antigens. CD56+ vs CD56- APL presented higher induction death rate (16% vs 8%, p =.02) and 5-years cumulative incidence of relapse (33% versus 10%, p =.006), irrespectively of the Sanz score (low-risk 47% versus 5%, p <.001; intermediate 23% versus 7%, p <.001; and high-risk 42% versus 21%, p =.007). In the multivariate analysis, CD56 + (p <.0001), higher relapse-risk score (p =.001), and male gender (p =.05) retained the independent predictive value. CD56+ APL also showed a greater risk of CNS relapse (6% versus 1%, p <.001) and lower 5-year OS (75% versus 83%, p =.003). The AIDA-based LPA2012 trial, with an intensified consolidation schedule for CD56+ APL, will elucidate whether an intensified consolidation schedule could mitigate the relapse rate in this setting. [ABSTRACT FROM AUTHOR]