Bortezomib in combination with fludarabine and cyclophosphamide for patients with relapsed or refractory mantle-cell lymphoma: results of the LYM-4003 study


 Background The LYM-4003 study was initiated to identify the maximum tolerated dose (MTD) of cyclophosphamide when combined with bortezomib and fludarabine in a phase 1b trial, and to assess the efficacy and safety of this combination in a phase 2 trial in patients with relapsed or refractory MCL. Methods Patients with relapsed or refractory MCL who had received at least one previous lines of treatment were enrolled in this single-arm, open-label, phase 1/2 trial at six major cancer centers in China. In phase 1, to identify the MTD of cyclophosphamide, 3 patient cohorts received escalating doses (150, 200, and 250 mg/m2) of intravenous cyclophosphamide on days 1, 2 of each 28-day cycle. Patients also received bortezomib 1.3 mg/m2 on days 1, 4, 8 and 11, fludarabine 25 mg/m2 on days 1, 2, 3 of each 28-day cycle. In phase 2 study, patients received bortezomib and fludarabine plus the MTD of cyclophosphamide. Treatment in both phases to maximum 6 cycles of chemotherapy, continued until disease progression, or severe toxicity. The primary endpoint was overall response. The secondary endpoint was survival. We used the Kaplan-Meier method to estimate response duration, progression-free survival, and overall survival. Analysis was by intention to treat population. Results 40 patients were enrolled between April 8, 2011 and October 10, 2015, 9 in phase 1 and 34 (including three patients who received the MTD of cyclophosphamide in phase 1) in phase 2. In phase 1, we identified the MTD as 250 mg/m2 cyclophosphamide. In phase 2, grade 3–4 hematological toxicities included thrombocytopenia, leucopenia, neutropenia, and lymphopenia. Among 32 patients in phase 2, 23 (72%) had an overall response: 10 (31%) had a complete response and 13 (41%) had a partial response. The median follow-up time was 31.6 months. The median response duration was 26.3 months. The median progression-free survival was 21 months (95% CI 7.3–34.7), and the median overall survival was 32.4 months (95% CI 17.8–47.0). Conclusions Bortezomib in combination with fludarabine and cyclophosphamide is highly effective and well tolerated for patients with relapsed or refractory MCL. Trial registration ClinicalTrials.gov NCT01322776 (Registered on March 25, 2011)


Introduction
Mantel cell lymphoma (MCL) is a distinct subset of B-cell non-Hodgkin's lymphoma characterized by cyclin D1 overexpression resulting from the t(11;14)(q13;q32) translocation [1][2][3]. MCL represents an aggressive form of non-Hodgkin's lymphoma, and is incurable with the current front-line treatments. Although high-intensity chemotherapy plus stem-cell transplant appears beneficial for progression-free survival (PFS), the median overall survival (OS) is approximately 3 years from diagnosis [4][5][6]. Recurrence despite high response rates to front-line regimens, often occurred with typical short duration of response (DOR) [2,5]. New approaches are urgently needed.
Results of synergistic cytotoxic effects of fludarabine and bortezomib have been shown in pre-clinical studies [18,19].
On the basis of these preclinical data, we hypothesized that the combination of bortezomib and FC might have more antitumor activity than either drugs alone for patients with relapsed or refractory MCL. To test this hypothesis, we initiated a single-arm, open-label, phase 1b/2 clinical trial to identify the maximum tolerated dose (MTD) of cyclophosphamide when combined with bortezomib and fludarabine and to assess the efficacy and safety of this combination in patients with relapsed or refractory MCL.

Patients
Patients with relapsed or refractory MCL who met the following criteria were eligible for this study: confirmed tissue diagnosis of MCL with CD20 and cyclin D1 positivity; had undergone one or two previous lines of treatment; and had an Eastern Cooperative Oncology Group performance status score of 2 or less. Additional eligibility criteria included an absolute neutrophil count of ≥ 1.5 × 10 9 cells per L, and a platelet count of ≥ 75 × 10 9 cells per L, aspartate aminotransferase and alanine aminotransferase concentrations of less than two times the upper limit of normal, and a creatinine clearance of more than 50 mL/min. A washout period of 4 weeks since previous therapy was required. Patients were excluded if they had grade 2 or higher peripheral neuropathy, signs of severe congestive heart failure (New York Heart Failure Guidelines Class III/IV) or active infection were present. Patients were also excluded if there was evidence that the lymphoma had involved the central nervous system, other condition likely to interfere with participation in this clinical study. Patients were excluded if they had received prior treatment with bortezomib (Complete eligibility and exclusion criteria are provided in the Supplementary Appendix).
This study was conducted in accordance with the Declaration of Helsinki and the International Conference on Harmonization Guidelines for Good Clinical Practice.
This study protocol was approved by the institutional review board of the Sun Yatsen University Cancer Center ethic committee (Reference number: YP2010170) and institutional review boards at each participant centers. Informed written consent was obtained from all participants before enrolment.

Procedures
In phase 1b, patients were sequentially enrolled in three cohorts to receive escalating of doses of 150 mg/m 2 , 200 mg/m 2 , and 250 mg/m 2 of intravenous cyclophosphamide by a 3 + 3 algorithm respectively. There were no intra-patient dose escalations. Patients received cyclophosphamide daily on days 1-2.
Bortezomib was given at 1.

Statistical analysis
In phase 1, the MTD of cyclophosphamide when combined with bortezomib and fludarabine was identified by a 3 + 3 algorithm. We used the Kaplan-Meier method to estimate response duration, progression-free survival (PFS), and overall survival (OS). Analyses were by intention-to-treat population. Response duration was calculated from the response date to the date of relapse, disease progression, or death. Eligible patients who achieved PR or better and who requested subsequent consolidation with SCT were censored for all response assessments at the time of SCT. For the response duration calculation, responders who went off study for any reason other than disease progression or death were censored on the last CT date.
Responders who did not experience disease progression but died of another reason were censored at the date of death. Responders who were still actively on study were censored at the survival date or the last CT date.
OS was defined as the time from study entry until death due to any cause, or until the last survival date if still alive. PFS was defined as the time from the start of treatment until lymphoma progression or death regardless of cause. Patients who were still actively on the study were censored at the survival date or the last CT date. The statistical calculations were done with IBM SPSS version 25.0.

Role of the funding source
Xian-Janssen provided free bortezomib and financial support. The sponsor of the study had no role in data collection, data analysis, or data interpretation. This investigator-initiated study was designed by the corresponding author who worked with co-authors at The Sun Yat-sen University Cancer Center and other hospitals.
We communicated and discussed the study design with the sponsor, but this did not lead to alteration of the study design. The sponsor reviewed the manuscript before submission and provided grammatical revisions. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.

Patients and enrollment
Between April 8, 2011 and November 7, 2011, 9 patients (per 3 patients at each dose level) were enrolled in the phase 1 portion of the study, 83% of whom were men ( Table 1). The median age was 60.5 years (range 41-74). Eight patients had one previous treatment and one patient had second prior lines of treatment. 89% of patient had received previous rituximab-containing treatments. Patients in phase 1 received a total of 40 cycles (median 4, range 2-6) of treatment.

Discussion
In this phase 1b/2 study, we identified the MTD of cyclophosphamide to be 250 mg/m 2 days 1-2 when combined with bortezomib and fludarabine. The combination was effective, with an OR of 72% and CR of 31% in patients with relapsed or refractory MCL.
The treatment of patients with relapsed or refractory MCL remains a major challenge [21]. Barr  The most common haematologic toxicity were neutropenia and thrombocytopenia.

Consent for publication
Not applicable.

Availability of data and materials
The authenticity of this article has been validated by uploading the key raw data onto the Research Data Deposit public platform (www.researchdata.org.cn), with the approval RDD number as RDDA2019001348

Competing interests
We declare no competing interests.

Funding
This study was financially supported by the Xian-Janssen pharmaceuticals company.

Author's contributions
XXW and HQH designed the study. HQH, XXW, YG, JJ, JNC, JFF, HLZ, QQC, ZML, and WQJ recruited and cared for patients. XXW and YG contributed to data collection and data assembly. XXW, YG and HQH did the data analyses and wrote the paper. All  Protocol_26866138LYM4003_XJP_20110505Final.doc