Rituximab maintenance therapy after autologous stem-cell transplantation in patients with relapsed CD20(+) diffuse large B-cell lymphoma: final analysis of the collaborative trial in relapsed aggressive lymphoma

Abstract

Purpose: The standard treatment for relapsed diffuse large B-cell lymphoma (DLBCL) is salvage chemotherapy followed by high-dose therapy and autologous stem-cell transplantation (ASCT). The impact of maintenance rituximab after ASCT is not known.

Patients and methods: In total, 477 patients with CD20(+) DLBCL who were in their first relapse or refractory to initial therapy were randomly assigned to one of two salvage regimens. After three cycles of salvage chemotherapy, the responding patients received high-dose chemotherapy followed by ASCT. Then, 242 patients were randomly assigned to either rituximab every 2 months for 1 year or observation.

Results: After ASCT, 122 patients received rituximab, and 120 patients were observed only. The median follow-up time was 44 months. The 4-year event-free survival (EFS) rates after ASCT were 52% and 53% for the rituximab and observation groups, respectively (P = .7). Treatment with rituximab was associated with a 15% attributable risk of serious adverse events after day 100, with more deaths (six deaths v three deaths in the observation arm). Several factors affected EFS after ASCT (P < .05), including relapsed disease within 12 months (EFS: 46% v 56% for relapsed disease after 12 months), secondary age-adjusted International Prognostic Index (saaIPI) more than 1 (EFS: 37% v 61% for saaIPI < 1), and prior treatment with rituximab (EFS: 47% v 59% for no prior rituximab). A significant difference in EFS between women (63%) and men (46%) was also observed in the rituximab group. In the Cox model for maintenance, the saaIPI was a significant prognostic factor (P < .001), as was male sex (P = .01).

Conclusion: In relapsed DLBCL, we observed no difference between the control group and the rituximab maintenance group and do not recommend rituximab after ASCT.

Trial registration: ClinicalTrials.gov NCT00137995.

Conflict of interest statement

Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article.

Figures

Fig 1.

CONSORT diagram of the patient distribution according to the treatment arm resulting from the second random assignment. ASCT, autologous stem-cell transplantation; CRF, case report forms; R-DHAP, rituximab, dexamethasone, high-dose cytarabine, and cisplatin; R-ICE, rituximab, ifosfamide, carboplatin, and etoposide.

Fig 2.

Treatment protocol. BEAM, carmustine, etoposide, cytarabine, melphalan; CR, complete response; PBPC, peripheral-blood progenitor cells; PD, progressive disease; PR, partial response; R, rituximab; R1, first random assignment; R2, second random assignment; R-DHAP, rituximab, dexamethasone, high-dose cytarabine, and cisplatin; R-ICE, rituximab, ifosfamide, carboplatin, and etoposide; SD, stable disease.

Fig 3.

Survival of patients after autologous transplantation. (A) Event-free survival (EFS) according to the second random assignment and treatment arm of rituximab (n = 122) or observation (n = 120). (B) EFS at the second random assignment according to disease status before transplantation (complete response [CR] plus unconfirmed CR [CRu], n = 142; partial response [PR], n = 92). (C) EFS at the second random assignment according to prior rituximab exposure (n = 125) or no prior rituximab (n = 117) during first-line treatment. (D) EFS at the second random assignment according to age-adjusted International Prognostic Index at relapse of 0 to 1 (n = 165) versus 2 to 3 (n = 72).

Fig 4.

Survival of patients after autologous transplantation according to sex. (A) Progression-free survival (PFS) at the second random assignment according to male (n = 159) or female (n = 83) sex. (B) PFS at the second random assignment according to male (n = 78) or female (n = 46) sex and the rituximab treatment arm. (C) PFS at the second random assignment according to male (n = 83) or female (n = 37) sex and observation.

Fig A1.

(A) Event-free survival (EFS) according to treatment arm from induction treatment. (B) Overall survival (OS) according to treatment arm (induction intent to treat). NA, not available; R-DHAP, rituximab, dexamethasone, high-dose cytarabine, and cisplatin; R-ICE, rituximab, ifosfamide, carboplatin, and etoposide.