High-dose cyclophosphamide for hard-to-treat patients with relapsed or refractory B-cell non-Hodgkin's lymphoma, a phase II result

Background: High-dose cyclophosphamide to treat solid refractory tumors demonstrated meaningful activity, while data to treat lymphoma remain scarce. This study aims to assess high-dose cyclophosphamide to treat relapsed or refractory lymphoma. Methods: A phase II study included adult patients with relapsed or refractory B-cell non-Hodgkin's lymphoma, previously treated by ≥2 prior lines with no other available option of therapy. High-dose cyclophosphamide was given intravenously 3 g/m² over two consecutive days and repeated once at 28 days in responding patients. Rituximab 375 mg/m² intravenously was added in patients not refractory to anti-CD20 antibody. Results: Forty-two patients with median age 65 [56-70] years were included. Patients had previously received a median of four lines of therapies. Tumor types were diffuse large B-cell lymphoma (n = 26; 62%), indolent B-cell non-Hodgkin lymphoma (n = 10; 24%), or mantle lymphoma (n = 6; 14%). Hematologic and non-hematologic grade 3-5 toxicities occurred in 42 (100%) and 18 (43%) of patients, respectively. The overall response rate was 45%. Conclusion: One to two cycles of high-dose cyclophosphamide in hard-to-treat patients with relapsed or refractory B-cell non-Hodgkin lymphoma demonstrated a favorable safety and efficacy profile. This regimen could serve as a bridge to modern cellular therapy with CAR-T cell.