A free lunch proof for Gray versus Binary encodings

Transformation from indolent non-Hodgkin lymphoma (NHL) to diffuse large B cell lymphoma (DLBCL) has historically been associated with a poor prognosis. A small series of autologous stem cell transplantation (ASCT) studies using conventional conditioning regimens has demonstrated durable progression-free survival (PFS) rates ranging from 25% to 47%, but data in the rituximab era are lacking. Here we report the results of a multicenter retrospective trial evaluating ASCT in patients with transformed lymphoma using the Z-BEAM conditioning regimen, which combines yttrium-90-labeled ibritumomab tiuxetan (Zevalin) with high-dose BEAM (carmustine, etoposide, cytarabine, melphalan) chemotherapy. Sixty-three patients from 4 institutions were treated between 2003 and 2011. Histological confirmation of transformation was required and defined as a diagnosis of DLBCL in patients with either a prior history or concomitant diagnosis of low-grade B cell NHL. Median patient age at ASCT was 59.5 years, median number of prior regimens was 2, and all patients were exposed to rituximab. Disease status at ASCT was as follows: first complete remission (CR) (n = 30), first partial remission (n = 11), first relapse (n = 14), and at least second CR (n = 8). The median time from diagnosis of histological transformation to ASCT was 7.5 months (range, 2.8 to 116). Two-year nonrelapse mortality was 0%. Median follow-up for living patients was 28 months (range, 5 to 103). Two-year PFS was 68% (95% confidence interval, 58% to 75%), and overall survival was 90% (95% confidence interval, 80% to 95%). In conclusion, the Z-BEAM conditioning regimen for ASCT is well tolerated by patients with transformed lymphoma and demonstrates encouraging clinical outcomes.