Impact Of Induction Regimen and Consolidative Stem Cell Transplantation In Patients With Double Hit Lymphoma (DHL): A Large Multicenter Retrospective Analysis

DHL are high-grade B-cell lymphomas (BCL) characterized by dual gene rearrangements (RA) of MYC and either BCL2 or BCL6. Outcomes are typically dismal, particularly when treated with R-CHOP, as compared to those observed in patients (pts) with similar histologies without dual RA. Few reports have evaluated the use of intensive induction regimens, with or without consolidative stem cell transplantation (SCT). We sought to evaluate the role of intensive induction as well as SCT, and to investigate predictors of outcome in DHL.

This study was an IRB-approved retrospective analysis across 15 centers. Cases were diagnosed between 2000-2012 as aggressive BCL harboring RA, by FISH, of MYC along with RA of BCL2 and/or BCL6. Pts were treated with either R-CHOP, or one of the following intensified regimens: R-HyperCVAD, R-EPOCH, R-CODOX-M/IVAC, R-ICE. Survival was estimated using Kaplan Meier method, and comparisons made with log rank test. Multivariable analysis (MVA) was performed using the Cox proportional hazard regression.

One hundred six pts were analyzed. Median age at diagnosis was 60; 59% were male. The majority had DHL characterized by RA of MYC and BCL2 (77%); the remainder showed RA of MYC and BCL6 (10%), or all three (12%). History of indolent lymphoma was present in 29 pts (27%). The most common histology was DLBCL in 56 pts (53%), followed by BCL unclassifiable (BCLU) in 45 (42%), and Burkitt-like in 5 (5%). Thirty six pts (33%) received R-CHOP, 33 (31%) R-EPOCH, and 28 (36%) R-Hyper-CVAD or CODOX-M/IVAC. Fourteen pts (13%) were consolidated with SCT (n=1 allo and n=13 auto SCT); all were treated with intensive induction. Three additional pts underwent SCT in partial remission or progressive disease following R-CHOP induction. The median PFS and OS for the entire cohort were 8.8 mo and 12 mo, respectively (Table 1); of the 24 pts (23%) alive and without progression, median follow-up was 19 mo. R-EPOCH was superior in achieving complete response (CR) compared with R-CHOP (P 0.01), and trended towards significance compared with pts receiving other intensive induction (P 0.07). Additionally, primary refractory disease, observed in 37 pts (34.5%), occurred less frequently in pts receiving R-EPOCH compared to R-CHOP (P .005) or other intensive regimens (P 0.03); induction regimen did not impact OS in patients not receiving SCT (P 0.7; Fig 1). SCT in first remission was associated with improved OS (P 0.02), and PFS (P 0.006) compared with induction alone. However, among pts achieving CR, SCT was not associated with improved OS compared with observation (P 0.22; Fig 2). Pts with prior history of indolent NHL did not fare worse than those with de novo DHL (P 0.5). No difference in OS was observed based on histology (P 0.2). The following factors were evaluated in MVA: prior indolent lymphoma, histological subtype, IPI>/=3, primary refractory disease, type of induction (R-CHOP vs intensified), and consolidative SCT. Only primary refractory disease (P<0.0001) predicted for inferior OS. Consolidative SCT did not improve OS on MVA (P 0.13).

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In this analysis of DHL, primary refractory disease was the primary predictor of OS. Pts achieving CR did not appear to benefit from consolidative SCT, though our analysis was limited by the fact that pts receiving SCT are often highly selected (for chemosensitivity, age, comorbidities) and in this study, by the low number of pts receiving SCT. R-EPOCH was associated with a decreased rate of primary refractory disease compared to other regimens, and increased rate of CR compared to R-CHOP, but the lack of clear survival benefit suggests that relapsed disease offsets early benefit. Our analysis confirms the generally poor outcomes for pts with DHL, though a subset with chemosensitive disease has an improved prognosis, likely due to favorable disease biology. Further investigation on the role of SCT and of novel agents is needed for this high-risk population.

^Three patients untreated, one received multiple regimens

Off Label Use: Brentuximab Vedotin is approved for relapsed, refractory Hodgkin Lymphoma in patients who have already had a transplant or are ineligible for one, or for patients with relapsed, refractory anaplastic large cell lymphoma. Patients treated on clinical trials or off label will be included in this presentation. Petrich:Genetech: Consultancy, Honoraria. Fenske:Seattle Genetics : Consultancy, Honoraria. Smith:Seattle Genetics, Inc.: Research Funding; Spectrum: Consultancy; Cephalon: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; GlaxoSmith Kline: Speakers Bureau. Evens:Seattle Genetics: Consultancy, Honoraria; Millennium: Consultancy, Honoraria, Research Funding; Ziopharm, Inc: Research Funding; Celgene: Consultancy, Honoraria.