The Prognostic Role of Cell of Origin Profile and Myc Expression Assessed By Immunohistochemistry in Young High-Risk Patients with Diffuse Large B-Cell Lymphoma (DLBCL): Results of First-Line Randomized BIO-DLCL04 Trial of Fondazione Italiana Linfomi (FIL)

Background. The prognostic role of cell of origin profile (COO) assessed by immunohistochemistry (IHC) is controversial in Rituximab era. FIL conducted a phase III randomized trial aimed at investigating the benefit of intensification with high dose therapy plus autotransplant compared to R-dose-dense therapy as first line in young DLBCL at poor risk (aa-IPI 2-3). Clinical results were reported (Vitolo, ASH 2012). The aim of BIO-DLCL04 was to correlate the biological markers with PFS. Patients and Methods. From 2005 to 2010, 412 untreated DLBCL at aa-IPI 2-3 were enrolled. Central histology revision was mandatory and 13 patients were excluded due to different histologies. Biological markers were analyzed on DLBCL NAS; COO analysis was performed by IHC and cases were classified in germinal center (GC) and non-GC according to Hans' algorithm; COO determined by gene expression profile using the NanoString® nCounter® Analysis System based on 20-gene assay (Lymph2Cx) using formalin fixed paraffin embedded tissue is ongoing; BCL2, BCL6 and MYC anomalies were tested by IHC; final analysis by fluorescent in situ hybridization (FISH) is ongoing. Cases were deemed positive if at least 30% of lymphoma cells were stained with each antibody (with the exception of at least 40% for MYC). Results. At the time of this analysis, 223 DLBCL NAS were analyzed: 131 non-GC and 92 GC; BCL2, BCL6 and MYC anomalies were tested in 196, 74 and 107 cases respectively. Clinical characteristics for non-GC vs GC were: median age 51 years for both, male 49% vs 45%, aa-IPI 3 15% vs 25%, bone marrow involvement (BM) 16% vs 24%. R-HDC was performed in 45% of non-GC patients and in 49% of GC. Complete response was recorded in 105 (80%) non-GC patients and in 62 (67%) GC. At a median follow-up of 49 months, the 3-year PFS for non-GC vs GC was 75% (95% CI: 67-82) vs 57% (95% CI: 46-67) with crude hazard ratio, HR 0.55 (0.35-0.87), p.01 and adjusted (for age, gender, aa-IPI, BM) aHR 0.56 (0.35-0.88), p.013. No significant differences by treatment were reported. Overexpression of MYC by IHC had a relevant prognostic impact, with aHR 1.84 (0.99-3.44), p.054. By IHC, 3-years PFS for double negative vs single BCL2 or MYC overexpression vs double positive, was 85% vs 68% vs 51% respectively, with an aHR for double expressors compared to double negative of 3.91 (1.13-13.53), p.031. At the time of the present report, FISH analysis was conducted in 88 cases: 43 were triple negative, 37 single hit and 8 double/triple hit. By FISH, 3-years PFS for triple negative vs single hit vs double/triple hit was 74% vs 84% vs 25% respectively, with an aHR for double/triple hit compared to triple negative of 5.73 (2.05 to 16.02), p.001. Conclusions. In conclusion, with the limit of the analysis performed by IHC based on Hans' algorithm, BIO-DLCL04 showed an unexpected better outcome for non-GC compared to GC, irrespective of treatment arm. The ongoing analysis conducted by Nanostring will be more informative. The overexpression of MYC was an unfavourable risk factor, mainly if associated with BCL2 overexpression, irrespective of type of treatment. Moreover, double/triple hit patients represent a subgroup with extremely poor prognosis. High dose therapy plus autotransplant was not able to reverse the inferior outcome of neither double expressors nor double hit patients and new strategies are deemed for these poor prognosis patients.