Outcome of Elderly Patients with Diffuse Large B-Cell Lymphoma Treated with R-CHOP: Subgroup Analysis from the UK NCRI R-CHOP 14 Vs 21 Trial

Background:

Elderly patients with diffuse large B-cell lymphoma (DLBCL) have an inferior prognosis compared to younger patients. Dose intense administration of cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP14) is superior to 3-weekly CHOP in elderly DLBCL patients (Pfreundschuh, Blood 2004), but this benefit has not been demonstrated with addition of rituximab (Delarue, Lancet Oncol 2013). We have previously shown that R-CHOP14 did not improve outcome compared to standard R-CHOP21 in newly diagnosed DLBCL patients aged 19-88 years across all subgroups (Cunningham, Lancet 2013). Here, we provide a detailed subgroup analysis of elderly patients (over 60 years) from the UK NCRI R-CHOP14 vs 21 randomised phase 3 trial.

Methods:

Between 2005 and 2008, 1080 patients were randomly assigned to receive 8 cycles R-CHOP21 or 6 cycles R-CHOP14 (+ G-CSF) with two additional rituximab applications. Of these, 604 patients were over 60 years and included in the current analysis (301 in the R-CHOP21 arm, 303 in the R-CHOP14 arm), with a median follow-up of 45 months.

Results:

Baseline characteristics were well balanced between treatment arms. 36% of patients were over 70 years, 15% had a WHO performance status (PS) of 2, 65% stage III/IV disease, 44% bulky disease and 42% B symptoms. There was a trend towards a higher rate of BCL6 rearrangements (26% vs. 16%; P=0.10) and concurrent MYC - and BCL2 rearrangements (double hit lymphoma as determined by FISH, 8% vs. 2%; P=0.06) in the R-CHOP14 arm compared to the R-CHOP21 arm.

85% (257/303) of patients received 8 cycles of R-CHOP14, whereas only 76% (230/301) completed all 8 cycles R-CHOP21. However, percentage of patients receiving at least 6 cycles of therapy was similar (88% and 89%, respectively). Dose delays of myelosuppressive drugs occurred more frequently in patients receiving R-CHOP21 vs. R-CHOP14 (51% vs. 39%; P=0.03) due to a higher incidence of haematological toxicities likely related to the reduced use of G-CSF. G-CSF was mandatory for patients on R-CHOP14 and was given to 57% of patients on R-CHOP21 as secondary prophylaxis. The frequency of dose reductions was similar in the R-CHOP21 and R-CHOP14 arms (15% vs. 16%; P=0.73). Toxicities of grade III+ were seen in 72% and 60% of patients in the R-CHOP14 and R-CHOP21 arms, respectively. There was evidence of a higher incidence of grade III+ neutropenia (62% vs. 36%) and a lower rate of thrombocytopenia (7% vs. 12%) in the R-CHOP21 arm compared to R-CHOP14. The incidence of fever and infections was similar in both arms.

There was no evidence of a difference in response rates between the R-CHOP14 and R-CHOP21 arms [complete response (CR)/unconfirmed CR (CRu) rates: 62% vs. 67%, respectively; overall response rate both 91%]. CR/CRu rates after 4 cycles of therapy were 33% and 39% respectively (P=0.15). There was no difference regarding progression-free survival (PFS) and overall survival (OS) between arms, neither in the total cohort of elderly patients, nor in the subgroup of patients over 70 years [OS (all elderly): hazard ratio (HR) 0.91 (95% CI: 0.67-1.24); P=0.55; PFS (all elderly): HR 0.98 (95% CI: 0.74-1.29); P=0.86]. 3-year PFS was 71% (95% CI: 67-74) in all patients over 60 years and 64% (95% CI: 58-71) in patients over 70 years. 3-year OS was 75% (95% CI: 72-79) and 67% (95% CI: 61-74) in patients over 60 years and over 70 years, respectively. In multivariate analysis including individual factors of the International Prognostic Index (IPI), as well as age as continuous variable, gender, presence of B symptoms, bulky disease, b2-microglobulin higher than 3mg/l and albumin higher than 35 g/l, only age was of independent prognostic significance for OS (P=0.01).

Besides the standard IPI and the NCCN-IPI, an elderly IPI (E-IPI; Advani, BJH 2010) and the ABE4 score (Prochazka, PLoS One 2014) have been proposed for better prognostication of elderly DLBCL patients. A detailed comparison of these different prognostic models in our dataset will be presented at the meeting.

Conclusion:

Outcome and toxicities in DLBCL patients over 60 years treated within the NCRI R-CHOP14 vs 21 trial are comparable to results from other randomised studies investigating R-CHOP14 or R-CHOP21 in elderly DLBCL patients. Our data further support the similar efficacy and tolerability of both R-CHOP variants for first-line treatment of this patient group.