Non-Effectiveness of Using RICE Post RDHAP or RDHAP Post RICE after Failure of First Line Salvage Therapy in DLBCL Patients Who Are Eligible for ASCT

Background: The treatment of relapsed or refractory diffuse large B cell lymphoma (DLBCL) remains challenging. The use of salvage chemotherapy followed by autologous stem cell transplantation (ASCT) in young and fit patients is considered the standard of care. RDHAP (rituximab, dexamethasone, high dose cytosine arabinoside and cisplatin) and RICE (rituximab, ifosfamide, carboplatin, and etoposide) are the two most commonly used salvage-regimens with comparable efficacy (CORAL study). However, nearly 40% of the patients do no respond to these regimens and subsequently they do not proceed to ASCT. There are no guidelines concerning the choice of a second-line salvage regimen. There are sparse data in the literature concerning the best choice if the first salvage regimen fails. The aim of our study was to investigate the potential role of a second salvage regimen, before intensification, by RICE or RDHAP in patients with DLBCL refractory to the first line salvage therapy by RDHAP or RICE, respectively.

Methods: We retrospectively included all patients aged 18 years and above who had a relapsed or refractory DLBCL and who were eligible for an autologous stem cell transplant (ASCT) between the years 2008 and 2017. They should have had progressive or stable disease (PD/SD) following first-line salvage based on RICE (group 1) or RDHAP (group 2) and should have received a second-line salvage based on RDHAP or RICE, respectively. Patients who received carboplatin or oxaliplatin instead of cisplatin in the RDHAP protocol were also included. All cases were discussed at a tumor board and the revised International Working Group response criteria for Malignant lymphoma were used to assess the response to chemotherapy. Information were collected using electronic medical record. Ethics committee approval was not necessary.

Results: 100 patients' medical files were reviewed, out of which 69 were excluded for the following reasons: 5 patients lacked necessary information; 13 patients were treated for a non-DLBCL; 30 patients could not receive second line salvage therapy because of deterioration of their performance status; 21 patients because they received a bridging therapy (other than RICE or RDHAP) before second line salvage therapy. The study included 31 patients with 19 (61.3%) males and 12 (38.7%) females. The median age was equal to 59 years (standard deviation 14). DLBCL was at the initial diagnosis in all but 6 patients in whom DLBCL developed after an indolent lymphoma (follicular lymphoma in 4 and marginal zone lymphoma in 2). 70% had germinal centre B-cell subtype, while 30% had activated B-cell subtype. 70% were refractory to the primary therapy (CR not attained on primary therapy or relapsed within 6 months) and 30% recurred after a CR lasting more than 6 months. All patients included in group 1 (n=5) have received cisplatin during the treatment with the RDHAP regimen. Among the 26 patients included in the second group, 19 (73.1%) have received cisplatin, 4 (15.4%) oxaliplatin, and 3 (11.5%) carboplatin in first line salvage. No patient in group 1 responded to RICE and eventually no patient proceeded to ASCT. In the second group, 2 patients (7.7%) deceased after the first cycle of RDHAP because of drug related toxicities (1 due to ifosfamide-induced encephalopathy and 1 due to septic choc following febrile neutropenia). Ten patients (38.5%) responded to RDHAP, in whom an ASCT was planned. However, 2 patients could not proceed to ASCT because of peripheral stem cell collection failure. After a median follow up of 8.7 months, the median progression free survival (PFS) of the 8 patients who proceeded to ASCT was 6.3 months (CI 95% 2.6-10.1). Only 1 patient had a tumor response lasting more than 30 months. No factor was found to be associated with PFS on cox regression analysis (which included age, sex, type of DLBCL, and refractory or recurrent status).

Conclusion: There is little information regarding the effectiveness of a second-line salvage therapy in patients not responding to first line intensification. All except one patient either could not proceed to ASCT or had a limited response (less than 3 months) post ASCT. In addition, the toxicity was not negligible considering that 2 patients died because of drug related events. This study suggests that patients with DLBCL who failed to respond to first line salvage by RDHAP or RICE should be considered for investigational therapies rather than second line rescue.