*4.2.1 Adolescents and young adults (AYA) with ALL*

AYA constitutes a unique group of ALL with an age range of 15–39 years as defined by the NCI. Based on disease biology, there has always been a debate as to the best regimen to be used in this age group. Historically, ALL in the AYA population has been associated with a poor outcome and higher treatment related morbidity. However, the current focus of treating AYA as per pediatric protocols has resulted in improvement in their outcomes [14, 15] as shown in **Table 1**. Chemotherapy protocols similar to the BFM backbone with corticosteroids, vincristine and asparaginase in induction, post-remission asparaginase, and CNS prophylaxis during induction have shown improved survival in this cohort of patients. Also, SCT is offered only to the very-high risk population in first complete remission (CR1) [80].

To support this further, the excellent results from the large study by the GRAALL group have shown significantly improved survival (66% vs. 44%, P < 0.001) for those treated with pediatric-inspired protocols compared to historical controls treated with adult protocols [81]. The largest study which has evaluated this hypothesis is the US intergroup trial C10403, in which 318 AYA patients were treated as per the standard arm of the COG AALL0232 protocol. Encouraging results from this study showed a 2-year event free survival (EFS) of 66% and overall survival (OS) of 78%, with manageable toxicity profile and subsequently the NCI recommended that pediatric-inspired protocols could be used effectively up to the age of 40 years [82].
