Lenalidomide and Low-dose Cyclophosphamide for MALT Lymphoma

\[Background\]: In addition to Helicobacter pylori-negative gastric marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (named as MALT lymphoma) (Sci Rep. 2017;7(1):14333), the investigators recently demonstrated that first-line antibiotics treatments can cure around 50% patients with stage IE/IIE1 extragastric MALT lymphoma (2018 ESMO poster discussion). However, the optimal management for antibiotics-unresponsive MALT lymphomas is not clearly defined. \[Rationale\]: The investigators previously reported that thalidomide resulted in an overall response rate (ORR, including complete remission \[CR\] and partial remission \[PR\]) of 50% in 10 patients with antibiotics-unresponsive or chemotherapy-resistant MALT lymphoma. Lenalidomide (an immunomodulatory derivatives \[IMiDs\] of thalidomide) exhibits anti-angiogenic and immunomodulatory effects and has been proved efficacies in the treatment of multiple myeloma (MM). In the previous phase II study, single agent of lenalidomide resulted in ORR of 61.1% in 18 patients with MALT lymphoma. In addition to kill lymphoma cells, single low-dose cyclophosphamide, is an option for restoring immune response in patients with advanced cancer. The investigators also showed that low-dose cyclophosphamide (50 mg daily for 21 days, every 28 days) alone resulted in the ORR of 44.4 % in 9 patients with antibiotics-unresponsive MALT lymphoma. Previous studies also demonstrated that the addition of low-dose cyclophosphamide can overcome lenalidomide resistance in patients with MM. \[Hypotheses\]: Considering that lenalidomide and cyclophosphamide are found to have anti-tumor effects in MALT lymphoma, the investigators speculated that combined lenalidomide and low-dose cyclophosphamide can increase the ORR rate as well as dural time of tumor remission, and avoid alternative treatments, including radiotherapy or chemotherapy-related adverse effects in antibiotics-unresponsive, relapsed or refractory extranodal MALT lymphoma. \[Methods\]: Therefore, in this proposal, the investigators will design a prospective phase II study to evaluate the treatment efficacies of combination of oral lenalidomide and low-dose cyclophosphamide (LC: lenalidomide \[Leavdo®\] 15 mg daily, day 1 to day 21; cyclophosphamide \[Endoxan\] 50 mg daily, day 1 to day 21; courses will be repeated every 28 days) in patients with antibiotics-unresponsive, relapsed or refractory extranodal MALT lymphoma. The primary endpoint of this current study is ORR, and the second endpoint is adverse effect. The investigators will enroll 21 patients with antibiotics-unresponsive, relapsed or refractory MALT lymphoma based on the Simon minimax two-stage design. The translational studies, including predictive markers and immunological profiles (BAFF-related canonical and non-canonical NF-κB signaling molecules, and immune-related molecules markers) will be included in the second points. The investigators will further assess immune-related molecules of nucleated cells of whole blood using flow cytometry, and analyze serum BAFF and cytokines.