High Survival Rate in Adult Burkitt’s Lymphoma/Leukemia and Diffuse Large B-Cell Lymphoma with Mediastinal Involvement.

With short intensive chemotherapy mainly based on HDMTX, fractionated alkylators and HDAC outcome of Burkitt’s NHL and mature B-ALL (B-ALL) in adults could be improved substantially to CR rates of 80% and overall survival (OS) of 50–70% (Hoelzer et al, Blood, 1996). Further intensification - namely increase of MTX dose - failed to improve these results. Therefore the German Multicenter Study Group for Adult ALL (GMALL) invented in 2002 a new protocol for mature B-ALL/Burkitt and other high-grade NHL, namely primary mediastinal (med) DLBCL, including 6x Rituximab® 375 mg/m² before each chemo cycle and two R maintenance cycles. In addition 2 cycles based on HDAC 2 g /m² were included. HDMTX was 1,5 g/m² in the protocol for younger pts (<55 yrs). Older pts (>55 yrs) received a dose reduced regimen without HDAC and with MTX at 500 mg/m². 227 pts with Burkitt (27=Burkitt-like), B-ALL or med DLBCL aged between 16 and 78 enrolled between 09/02 and 12/06 were evaluable for response after the first two cycles. The median age was 36 yrs for Burkitt, 46 for B-ALL and 35 for med DLBCL; 18%, 41% and 12% were older than 55 yrs respectively. The subgroups were characterised as follows: 115 Burkitt (stage III–IV 52%, extranodal inv. 78%, aaIPI >1 47%), 70 B-ALL, 42 med DLBCL (stage III–IV 55%, extranodal inv. 71%, aaIPI >1 61%). The CR rate was 90% in Burkitt, 83% in B-ALL and 69% in med DLBCL; death under therapy occurred in 3%, 11% and 0% respectively. The overall survival at 3 yrs was 91% for Burkitt, 79% for B-ALL and 90% for med DLBCL in pts at the age of 15–55 yrs and 84%, 39% and 67% (N=5) respectively in pts >55 yrs. CNS relapses were observed in 3 out of 22 older CR patients with B-ALL whereas in younger pts the CNS relapse rate was 0. CNS relapses are among the reasons for inferior outcome in elderly B-ALL in contrast to elderly pts with Burkitt or med DLBCL. CNS relapse rate may hopefully be reduced by inclusion of an intermediate dose ARAC cycle in the elderly B-ALL. There was no difference in OS between pts with Burkitt (92%) vs Burkitt-like NHL (86%). Since no prognostic factors could be identified in younger pts, there was no need for SCT in CR1. Major grade III/IV toxicity was hematological (28–37%) and mucositis (36%, 37%, 28% in cycles A1, B1, C1 respectively). Compared to the previous GMLL trial B-NHL90 (without Rituximab) with 270 pts the OS of 272 patients (including LBL, LCAL, DLBCL) at 3 yrs improved significantly from 54% to 80% (p<.0001) overall, 56% to 85% (p<.0001) in younger and 39% to 65% (p=.01) in older pts. In this largest prospective study of adult Burkitt’s lymphoma/leukemia and med DLBCL the combination of Rituximab and 6 short intensive chemo cycles was feasible and lead to an OS of 90% in NHL and 79% in mature B-ALL in the younger patient cohort. Even in older pts with Burkitt’s NHL survival was 84%. The further aim is now to reduce toxicity, namely mucositis.