The Short-Term Efficacy and Safety of Obinutuzumab Plus Chemotherapy in B-NHL with High Tumor Burden: A Real-World, Retrospective Study

Introduction: The prognosis of patients with B-cell non-Hodgkin's lymphoma (B-NHL) in high tumor burden is significant poor and patients frequently occur tumor lysis syndrome (TLS) during chemotherapy. There are no standard treatment regimens at present, so it is very crucial to explore effective treatment options to improve prognosis. The aim of present study is to analysis the short-term efficacy and safety of obinutuzumab plus chemotherapy in B-NHL with high tumor burden.

Methods: We retrospectively investigated the records of 19 patients of B-NHL with high tumor burden and received obinutuzumab treatment at the First Hospital of Jilin University from November 2021 to July 2022, including 9 marginal zone lymphoma (MZL), 7 chronic lymphocytic leukemia /small lymphocytic lymphoma (CLL/SLL), 2 mantle cell lymphoma (MCL), 1 B-prolymphocytic leukemia (B-PLL). All patients received obinutuzumab at a dose of 1000 mg (on days 1, 8, and 15 of cycle 1 and on day 1 of subsequent cycles). The primary endpoint was objective response rates (ORR), and secondary endpoints was incidence of adverse events (AEs).

Results: This study enrolled 19 patients completed ≥ 1cycles obinutuzumab plus chemotherapy, including 8 patients with initial treatment and 11 with relapsed and refractory (R/R). Among them, 15 received obinutuzumab with bendamustine (BG), 3 with Bruton tyrosine kinase inhibitors (G-BTKi), 1 with COP (cyclophosphamide, vincristine, and prednisone; G-COP). The median age was 65 years (range, 41-83 years); 12 males and 7 females. In addition, 94.7% patients (18/19) were identified with advanced stage; 73.7% (14/19) with B symptoms; 52.6% (10/19) with ECOG ≥ 2; 57.9% (11/19) with elevated lactate dehydrogenase (LDH) levels; 100% with elevated beta-2 microglobulin (β2MG) levels. 94.7% patients could quickly relieve the high tumor burden status after 1cycle obinutuzumab treatment (Figure 1A). Furthermore, there are 6 patients with hyperleukocytosis (blood cell count greater than 100,000/mL), all reduce to normal level on day 4 of obinutuzumab treatment (Figure 1B); 12 patients with splenomegaly, including 11 massive splenomegaly (long axis >20 cm), all significantly decreased after obinutuzumab treatment, and 7 patients has returned to normal level, and patients with enlarged lymph nodes also significantly reduced after obinutuzumab treatment (Figure 1C). Besides, 8 patients measured minimal residual disease (MRD) in peripheral blood and 6 (75%) achievement of undetectable MRD. Significantly, the ORR was 94.7% (18/19), and 57.9% (11/19) achieved complete remission by evaluation of images. (Figure 1D).

The most common AE of any grade were infusion-related reactions 7/19 (36.8%); expiratory dyspnea 2/19 (10.5%); nausea 1/19 (5.3%). In addition, 9/19(47.4%) neutropenia, which may also associate with chemotherapy. There was no incidence of AEs leading to treatment withdrawal or death under obinutuzumab plus chemotherapy treatment.

Conclusions: Obinutuzumab could quickly relieve the high tumor burden status and decrease the occurrence of TLS. Thus, obinutuzumab is a promising treatment in patients of B-NHL with high tumor burden.

No relevant conflicts of interest to declare.