The Mini-Teddi-R Treatment Demonstrated a High Rate of Remission in Patients with DLBCL Involving the CNS Who Had Previously Been Exposed to BTK Inhibitors

Background: Secondary CNS B-cell lymphomas (SCNSL) are aggressive lymphomas with a bleak prognosis. TEDDI-R has been successful in achieving lasting remission in relapsed/refractory primary DLBCL of the CNS (PCNSL), but the effectiveness of ibrutinib-responsive tumors in SCNSL remains unknown. This study presents initial findings from the use of mini-TEDDi-R in SCNSL.

Methods: Efficacy and safety data of mini-TEDDi-R were retrospectively analyzed for patients with DLBCL involving the CNS. All patients experienced relapse in the CNS or/and peripheral region after initial therapy. Brain parenchyma involvement allowed for treatment with MTX, Ara-c, and/or BTK inhibitors. The dosage of the drugs used in the original regimen was reduced, leading to the adoption of the term “mini-TEDDi-R.” Each 21-day cycle involved the following treatments: intravenous rituximab at a dose of 375 mg/m ²/day on days 1-2, oral temozolomide at a dose of 150 mg/m ²/day on days 2-5, intravenous infusion of 30 mg/m ²/day etoposide on days 2-5, intravenous infusion of 25 mg/m ² of pegylated liposomal doxorubicin on day 2, intravenous infusion of dexamethasone at a dose of 10 mg/m ²/BID on days 1-5, and oral zanubrutinib at a dose of 200mg/BID or oral orelabrutinib at a dose of 150mg/qd or oral ibrutinib at a dose of 560mg/qd from day 1 until neutrophil count <0.5*10^9/L or platelet count <30*10^9/L. Additionally, intrathecal administration of 70 mg of cytarabine occurred on days 1 and 5, All remissions observed on MRI were confirmed through FDG-PET and CSF analysis.

Results: Between December 2019 and June 2023, 24 patients with a median age of 53 (range 28-69) received mini-TEDDi-R treatment. All patients had DLBCL, comprising 16 (66.7%) non-GCB, 6 (25%) GCB, and 2 (8.3%) transformed from FL. All patients experienced relapse in the CNS system after a median of 6 (range 1-17) prior therapies, and all (100%) patients received prior anthracycline treatment. A total of 21 patients (87.5%) had received multiple lines of therapy before mini-TEDDi-R. Among them, 19 patients (79.2%) had received HD-MTX based salvage therapy, 11 patients (45.8%) had received HD-Ara-c based salvage therapy, and 14 patients (58.3%) had been exposed to BTK inhibitors. Seven patients (29.2%) showed triple resistance to MTX, Ara-c, and BTK inhibitors. Six patients had previously undergone transplantation, and four patients had experienced failure of CD19 CART treatment. Thirteen patients (54.2%) had isolated CNS disease, while 11 patients (45.8%) had both CNS and peripheral disease. Thirteen patients (54.2%) underwent 1 cycle of mini-TEDDi-R, 8 patients (33.3%) completed 2 cycles, 2 patients (8.3%) finished 3 cycles, and 1 patient (4.2%) completed 4 cycles.

The objective remission rate (ORR) was determined to be 70.8%, with a complete remission (CR) rate of 58.3%. Notably, patients (N=14) exposed to BTK inhibitors previously exhibited a similar CR rate compared to patients (N=10) who had not received prior BTK inhibitor treatment (50% vs. 70%, p = 0.348). Patients (N=19) who had undergone HD-MTX based salvage therapy achieved an ORR of 74% and a CR rate of 58%. No significant difference in response rate was observed between patients with peripheral and non-peripheral secondary CNS involvement. In patients who achieved complete remission, only one patient experienced a second CNS relapse. Four patients bridged to auto-HSCT, 2 patients bridged to CART treatment, and 4 patients underwent auto-HSCT combined with CART treatment for consolidation. The median overall survival and median PFS have not been reached within the 11.8-month follow-up period.

Toxicity was evaluated over 39 cycles. Grade 3 and 4 neutropenia occurred in 51% and 16% of cycles, respectively, while febrile neutropenia was observed in 10% of cycles. The median duration of neutropenia was 6 days (range 4-10). Three cycles (8%) were complicated by infections graded as ≥G3, but no opportunistic infections (including Aspergillus) were observed. Grade 3 and 4 thrombocytopenia occurred in 26% and 14% of cycles, respectively. The median duration of neutropenia was 7 days (range 3-14).

Conclusions: The mini-TEDDi-R regimen demonstrated a favorable remission rate in patients with DLBCL involving the CNS. The treatment was well-tolerated, and patients with tumors that were previously exposed to BTK inhibitors and HD-MTX treatment also showed positive responses to mini-TEDDi-R.