Effects of a pediatric-inspired chemotherapy regimen vs an adult regimen on CNS relapse risk in adult patients with ALL

Extramedullary relapse in acute lymphoblastic leukemia (ALL) commonly occurs in the central nervous system (CNS), with 7–15% of adult patients with ALL experiencing CNS relapse. Pediatric-inspired chemotherapy regimens have demonstrated potential in adults with ALL, with 5-year survival rates of ~60% in adolescents and young adult patients.

A recent study investigated the effect of the pediatric-inspired Precision Classification-Directed Target Total Therapy-ALL-2016 (PDT-ALL-2016) regimen (n = 409), compared with the cyclophosphamide + vincristine + doxorubicin + dexamethasone (hyper-CVAD) regimen (n = 596), on CNS relapse in adult patients with ALL. The primary endpoint was CNS relapse. Results were published by Liang et al. in the British Journal of Haematology.

Key learnings 

Significantly fewer patients treated with the pediatric-inspired regimen experienced CNS relapse than those treated with the adult regimen (7.09% vs 11.24%, respectively; p = 0.037). 

The 5-year CIR in the CNS was lower with the pediatric-inspired regimen than with the adult regimen (7.09% vs 11.24%; p = 0.025), including in a high-risk subgroup (n = 311; 6.75% vs n = 366; 13.7%; p = 0.003).

Factors associated with reduced risk of CNS relapse in univariate analysis included allo-HSCT (OR, 0.52; p = 0.0030) and the pediatric-inspired regimen (OR, 0.60; p = 0.029).

These results indicate that pediatric-inspired chemotherapy regimens may reduce the risk of CNS relapse in adult patients with ALL, compared with adult regimens.