Relapses of childhood ALL that occur on therapy are associated with a dismal survival. To improve the prognosis for these patients, we developed an intensive multiagent chemotherapy protocol consisting of an induction with idarubicin, vincristine (VCR), dexamethasone (DEX), and peg-asparaginase (PEG). Consolidation included high-dose cytarabine (ARA-C), etoposide (VP-16), and PEG followed by VCR and methotrexate (MTX). After an interim maintenance (IM), induction and consolidation were repeated followed by maintenance therapy lasting two years. Maintenance and IM consisted of alternating two week cycles of VP-16, ARA-C, and PEG, with MTX ,VCR, DEX, and PEG. Between 1992 and 2002, 53 pts (32M, 21F) received treatment according to this protocol, 21 of whom were treated as part of the original study (
Leahey AM et al., Med Ped Onco34(5):313–8, 2000
). Median time to relapse was 37 months from diagnosis (range 12–86 mos). Twenty-one pts were on therapy at relapse and 25 pts were <36 months from diagnosis. Relapses included isolated bone marrow (BM) (32 pts), BM and central nervous system (CNS) (9 pts), BM and testicular (3 pts), and extramedullary (EM) (9 pts). By present day criteria 26 pts were standard risk (SR), 23 were high risk (HR), and 4 were infants. Two patients died in induction, and 2 never achieved a second remission. All others achieved remission by the end of induction (92%). Five-year event-free survival (EFS) and overall survival (OS) are both 56% +/−7% (CI 41%–68%), at a mean of 47 months from relapse (range 0–141 mos). Patients with a first complete remission (CR1) duration <36 months have an EFS of 40% +/−10% (CI 21%–58%); >36 months CR1 is associated with an EFS of 70% +/−9% (CI 50%–84%). Of the events in all pts who initiated therapy,13 were from refractory/recurrent ALL (25%), and 10 pts died of toxicity (19%). Four pts died from chemotherapy induced toxicity (8%), and 6 died from transplant (BMT) related toxicities (11%). Fourteen pts in second remission proceeded to BMT at a mean of 5 months from relapse (range 4.5–8 mos), and 7 of these pts remain in CR2. Of the 39 pts who continued on chemotherapy, 6 pts (35%) with CR1<36 months remain in CR2 and 16 patients (57%) with CR1>36 months remain in CR2 or 3. The 19 pts who were treated on modern standard risk (SR) protocols (CCG-1881 to present) were more salvagable than their 20 high risk (HR) counterparts (CCG-1882 to present). Five year EFS for SR and HR pts is 67% +/−8% (CI 48%–80%) and 38% +/−12% (CI 16%–59%) respectively. Intensive rotating therapy with reinduction and reconsolidation improves EFS. Children with early EM relapses of ALL, CR1 > 36 months, and SR patients all have very good long term survival. Novel therapies need to be integrated into intensive relapse protocols for children with early BM relapse and children treated upfront on HR protocols.
