Improved Outcome of Adult Acute Lymphoblastic Leukemia Treated with Individualized Protocol Adjusted to the Status of Minimal Residual Disease and Age. Interim Analysis of PALG ALL 5–2007 Study

Abstract 2138

In a previous study by the Polish Adult Leukemia Group (PALG 4–2002) we demonstrated that status of minimal residual disease (MRD) during induction-consolidation is the most important factor predicting long-term outcome of adult ALL (Br J Haematol 2008). In a new PALG 5–2007 protocol the treatment was intensified for patients with MRD level >0.1% of bone marrow cells and adjusted to age. Induction consisted of Epirubicine(4×), Vincristine(4×), Prednisone and PEG-asparaginase. Patients with complete remission (CR) but MRD >0.1% obtained additional 2nd phase of induction: AraC+Cyclophosphamide(Ctx) + 6MP. Consolidation consisted of 2 courses of Methotrexate(Mtx) + Etoposide + Dexamethasone and subsequent 2 cycles of Ctx + high dose AraC, asparaginase, intrathecal prophylaxis and CNS irradiation. Doses of Mtx were 500 mg/m2 for patients with MRD<0.1%, aged >35y and 1500 mg/m2 for all remaining ones. For Ph+ ALL imatinib 600 mg/d was administered in parallel to chemotherapy. Patients with standard risk disease continued with 2 years maintenance while those with high-risk were referred for alloHSCT. High risk was defined as the presence of at least one of: initial WBC >30×10e9/L, age >35y, pro-B, early-T, mature-T, late CR, t(9;22), t(4;11) or MRD >0.1% at any time during induction-consolidation.

Results of PALG 5–2007 protocol (N=108, median age 32y, range 16–55y) were compared to PALG 4–2002 (N=253, age 28y, range 16–55y), in which MRD status was not taken into account for treatment decisions. CR rate was 92% for PALG 5–2007 compared to 89% for PALG 4–2002. The probability of the overall survival at 36 months was 56% vs. 33% (p=0.02), while leukemia-free survival was 53% vs. 28% (p=0.04), respectively. The probability of relapse decreased from 54% in PALG 4–2002 to 16% in PALG 5–2007 (p=0.002). In a multivariate analysis adjusted to age, initial WBC and the presence of t(9;22) treatment according to PLAG 5–2007 protocol was associated with decreased risk of mortality (HR=0.57, p=0.02), relapse (HR=0.37, p=0.006) and treatment failure (HR=0.64, p=0.049).

We conclude that individualized therapeutic approach with treatment intensity adjusted to MRD status and age may result in improved outcome of adults with ALL.

*This multi-institutional study was supported by Polish Ministry of Sciences Grant NN-402366433