Response: “Lesser” ALL: should it be studied further as research budgets are diminishing?

We appreciate the letter by Drs Relling et al from St Jude Children's Research Hospital regarding our recent Inside Blood commentary.¹ 

We certainly agree with their exhortation that children with even the most favorable risk acute lymphoblastic leukemia (ALL) should continue to be studied, but need to point out a few errors in their comments:

(1) The delayed intensification phase of Children's Cancer Group (CCG) 1922 included 7 (not 8) systemic agents and the total number of vincristine/steroid pulses after remission induction was 25 for females and 37 for males (not 32 for all patients).

(2) Their literature citation for relapse beyond 6 years from diagnosis needs to focus on the patients with “lesser-risk” ALL (not all patients with ALL). This risk with contemporary therapy appears to be vanishingly small. We have yet to observe a single instance of relapse beyond 6 years in this patient group in the last 17 years, and there were none noted 7 years after study closure in the 1057 children who attained remission in CCG 1922 (Bruce Bostrom, study chair, CCG 1922, oral communication, August 31, 2007).

In addition, and more important, the fact is that funding for clinical trials by the Children's Oncology Group (COG) has been cut in the past several years and hard decisions have been made regarding what gets studied in the group. Until funding gets restored to its previous level, we suggest that a more appropriate target for clinical studies in ALL would be those children with ALL of higher initial risk and/or those who unfortunately relapse. Gaynon et al have shown that relapsed ALL is, in fact, the fourth most common diagnosis in pediatric oncology.²  The ultimate outcome with current therapy for most of these children is poor, and we need to better understand the basic biologic reasons for this.