Clinical Trial to Determinate Dose, Security and Efficacy or Lenalidomide and Rituximab (LR)-ESHAP in Patients With Diffuse Large B-cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most frequent subtype of non-Hodgkin's lymphoma (NHL), comprising approximately 30% of new cases. Treatment results of DLBCL have significantly improved after the introduction of rituximab (R) into CHOP-like, anthracycline-based, treatment schedules, and it is now the standard of care. Nevertheless, even with current R-CHOP-like treatment, approximately 30-40% of patients will ultimately relapse or progress.

To date, high-dose therapy (HDT) followed by autologous stem-cell transplantation (ASCT) is the reference treatment for patients with relapsed or primary refractory aggressive B-cell NHL, provided the disease is sensitive to second-line chemotherapy. Among patients with chemosensitive disease, the remission status at transplant has a significant impact on the outcome, because patients in complete remission (CR) before HDT achieve better long-term progression-free survival (PFS) than patients who undergo transplantation in partial remission (PR). Standard salvage chemotherapy for aggressive lymphoma does not exist. Commonly used second-line regimens include dexamethasone, cytarabine, cisplatin (DHAP), ESHAP (etoposide, methylprednisone, cytarabine, cisplatin), mini-BEAM (carmustine, etoposide, cytarabine, melphalan) and ICE (ifosfamide, carboplatin, etoposide). These regimens produce an overall response rate (ORR) of around 60%, and CR rates of 25% to 35%. More effective salvage regimens are needed in order to maximize the number of patients in CR prior to ASCT.

Increasing evidence suggests that rituximab added to salvage chemotherapy improves response rates and outcomes in relapsed DLBCL. In a recent randomized phase 3 study, the efficacy of adding rituximab to the DHAP-VIM-DHAP regimen was tested in 239 rituximab-naïve patients with relapsed or primary refractory aggressive cluster of differentiation 20 (CD20)+ B-cell NHL. In 225 evaluable patients, the addition of rituximab to second-line chemotherapy resulted in a significant improvement of ORR (75% versus 54%, p=.01) and PFS (52% versus 31% at two years, p<.002). Other small phase II trials (with a range of 35-55 patients) investigating rituximab in combination with ICE, DHAP or EPOCH have also shown encouraging results. However, the patients in these studies had not been previously exposed to rituximab, while at present, almost all patients with aggressive B-cell NHL receive rituximab combined with first-line chemotherapy.

In a recent multicenter retrospective study, we analyzed the influence of prior exposure to rituximab on response rates and outcomes in 163 patients with relapsed or refractory DLBCL who received Rituximab-ESHAP (R-ESHAP) as salvage therapy with a curative purpose. In this study, prior exposure to rituximab did not have an independent effect on response rates to R-ESHAP. However, a high proportion (57.4%) of patients who had received prior rituximab treatment experienced disease relapse or progression, that translated into a significantly worse PFS (17 v 57% at 3 years) and OS (38% v 67% at 3 years) as compared with rituximab-naïve patients. This observation was independent of other prognostic factors with an impact upon these outcomes, such as disease status at R-ESHAP, age-adjusted International Prognostic Index (IPI) or response to R-ESHAP. Results of the CORAL randomised trial comparing R-ICE with R-DHAP in 396 patients with relapsed or refractory DLBCL confirmed that exposure to rituximab prior to salvage therapy is associated with a worse outcome . Rituximab naïve patients had a 83% response rate and 47% 3-year event-free survival (EFS) compared with a 51% response rate and 21% EFS for patients who had received prior rituximab treatment.

These results suggest that the use of highly effective rituximab-containing primary therapy in DLBCL makes it more difficult to salvage patients who are refractory or who relapse. Thus, prospective studies incorporating new agents are needed for these patients.

Lenalidomide:

Lenalidomide, an analog of thalidomide, is a promising new therapeutic agent that does not seem to cause significant somnolence, constipation, and neuropathy, which are usually dose-limiting for thalidomide. It has been hypothesized that the mechanism of action of lenalidomide includes immunomodulatory, antineoplastic, anti-angiogenic and pro-erythropoietic properties. Preclinical as well as clinical observations demonstrate that lenalidomide downregulates production of various critical prosurvival cytokines in the tumour microenvironment while concurrently promoting activation of T- and natural killer (NK) cell-mediated antitumour response. In aggressive lymphomas, lenalidomide was shown to exert antiproliferative activity by enhancing the expression of cell cycle regulators, including p21 and SPARC, to induce G1 cell cycle arrest, caspase activation, and apoptosis.

In a recent phase II multicenter trial, 49 patients with relapsed or refractory aggressive NHL (diffuse large B-cell, follicular center grade 3, mantle cell, and transformed lymphomas) received oral lenalidomide monotherapy, 25 mg once daily on days 1 to 21, every 28 days, for 52 weeks, until disease progression or intolerance. The most common histology was diffuse large B-cell lymphoma. The median age was 65 years (range: 23 to 86). Patients had received a median of four prior treatment regimens; 56% were refractory to last therapy and 29% had received a prior ASCT. An objective response rate of 35% was observed in 49 treated patients, including a 12% rate of complete response/unconfirmed complete response. Responses were observed in each aggressive histologic subtype tested (19% ORR in patients with DLBCL). Of patients with stable disease or partial response at first assessment, 25% improved with continued treatment. Estimated median duration of response was 6.2 months, and median PFS was 4.0 months. The most common grade 4 adverse events were neutropenia (8.2%) and thrombocytopenia (8.2%); the most common grade 3 adverse events were neutropenia (24.5%), leukopenia (14.3%), and thrombocytopenia (12.2%). The results of this study show that lenalidomide monotherapy is active in relapsed or refractory aggressive NHL, with manageable side effects.

A confirmatory international phase II trial (NHL-003) of single-agent lenalidomide was performed for patients with relapsed/refractory aggressive NHL that had received at least one prior treatment and had measurable disease. Patients received 25 mg oral lenalidomide once daily on days 1-21 of every 28-day cycle and continued therapy until disease progression or toxicity. 217 patients enrolled and received lenalidomide. The ORR was 35% (77/217), with 13% (29/217) CR, 22% (48/217) PR, and 21% (45/217) with stable disease. The ORR for DLBCL was 28% (30/108), 42% (24/57) for mantel-cell lymphoma, 42% (8/19) for grade 3 follicular lymphoma, and 45% (15/33) for peripheral T-cell lymphoma. Median progression-free survival for all 217 patients was 3.7 months [95% confidence interval (CI) 2.7-5.1]. For 77 responders, the median response duration lasted 10.6 months (95% CI 7.0-NR). Median response duration was not reached in 29 patients who achieved a CR and in responding patients with follicular lymphoma (FL)-III or mantle cell lymphoma (MCL). The most common adverse event was myelosuppression with grade 4 neutropenia and thrombocytopenia in 17% and 6%, respectively.The results of this international study confirm that lenalidomide is active in heavily pre-treated patients with relapsed or refractory DLBCL with manageable side effects.

The results from these phase II studies demonstrate the activity of oral lenalidomide monotherapy in patients with relapsed or refractory aggressive NHL and warrant further investigation of lenalidomide therapy, alone or in combination, in the treatment of patients with aggressive NHL. It was recently reported that when used in combination, lenalidomide (maximum-tolerated dose [MTD] 20 mg/day, 21 of 28 days) and rituximab produce a robust response rate in relapsed or refractory mantle cell lymphoma, with a favourable toxicity profile. In multiple myeloma (MM) patients, several phase 1/2 trials have evaluated lenalidomide in conjunction with chemotherapy, such as melphalan and prednisone (MTD 10 mg/day, 21 days every 4 to 6 weeks), doxorubicin and dexamethasone (MTD 25 mg/day with G-Colony-stimulating factors (CSF), 21 of 28 days), or doxorubicin, vincristine and dexamethasone (MTD 10 mg/day, 21 days every 4 to 6 weeks). These combinations provide a considerable proportion of high-quality responses with substantial durability in patients with MM and overcomes several well-known adverse prognostic factors. A phase 1 study showed that lenalidomide can be safely combined with R-CHOP (R2CHOP) in the initial chemotherapy for aggressive B-cell lymphomas. Preliminary results of ongoing phase 2 suggest that the addition of lenalidomide to rituximab, cyclophosphamide, adriamycin, vincristine and prednisone (RCHOP) could overcome the negative prognostic impact of the non-germinal center B-cell (GCB) phenotype on outcome.

Thus, we propose an open-label, non-randomized, multicentre, escalating-dose, Phase I trial, to investigate the safety and the maximum-tolerated dose of the combination R-ESHAP with lenalidomide as salvage therapy for patients with relapsed or refractory diffuse large B-cell lymphoma candidates to stem-cell transplantation. We expect haematological toxicity as the main form of toxicity, as shown in previous studies. We must also take into account the possible adverse influence of lenalidomide treatment on stem cell mobilization. In patients with MM, prior lenalidomide therapy has been associated with high rates of failure in stem cell mobilization with filgrastim. Remobilization with chemotherapy and filgrastim is usually successful in these patients.

After selection of the maximum-tolerated dose of the combination R-ESHAP with lenalidomide a phase 2 of the study will be performed in order to evaluate the ORR of LR-ESHAP.

Partial data verification will be performed. A Clinical Research Organization (Dynamic Science S.L) Standard Operating Procedures will be used to manage the clinical trial.

Categorical variables were show by absolute and relative frequencies, including the confidence interval of 95%.

For the description of the continuous variables will be use the mean, standard deviation, median, mode, minimum and maximum, including the total number of valid values.

In the case of compare subgroups of patients, will be use for quantitative variables parametric tests or nonparametric as characteristics of the variables under study. For qualitative variables will be use Chi-square test.

Statistical analysis was planned with the Statistical Analysis System (SAS) package version 9.1 or later.