Favourable outcomes of poor prognosis diffuse large B-cell lymphoma patients treated with dose-dense Rituximab, high-dose Methotrexate and six cycles of CHOP-14 compared to first-line autologous transplantation

Ideal dose intensity of R-CHOP in diffuse large B-cell lymphoma

INTRODUCTION

The standard of care for diffuse large B-cell lymphoma (DLBCL) is rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). However, its ideal dose intensity varies among cases.

AREAS COVERED

This review provides the latest insights on the dose intensity of R-CHOP for DLBCL patients. Specifically, we discussed the optimal dose intensity for elderly patients, the optimal number of treatment cycles for limited or advanced-stage diseases, and the role of dose-intensified therapies or adding targeted inhibitors.

EXPERT OPINION

Performing a comprehensive or simplified geriatric assessment can distinguish elderly DLBCL patients who will likely benefit from curative R-CHOP. Very elderly or medically unfit patients may need dose reduction in R-CHOP; the Age, Comorbidities, and Albumin index may aid decision-making. Four cycles of R-CHOP followed by two rituximab cycles comprise a new standard for low-risk, limited-stage DLBCL patients. Compared to eight cycles, six cycles of R-CHOP have similar efficacy and fewer toxicities for advanced-stage DLBCL. Dose-intensified therapy is not recommended in most DLBCL cases but may be considered for patients with double (or triple)-hit lymphoma. Applying targeted inhibitors and not merely escalating R-CHOP dose intensity through molecular subtyping will improve the treatment outcome for DLBCL.

Rituximab Concentration Varies in Patients With Different Lymphoma Subtypes and Correlates With Clinical Outcome

Individual variations in concentrations of rituximab in different B cell non-Hodgkin's lymphoma subtypes and their relevance to efficacy were still unclear. From 2016 to 2021, a prospective clinical trial was conducted, and 510 samples with 6 uncommon subtypes of B-cell lymphoma were enrolled to examine the pharmacokinetic behaviour of rituximab and its impact on clinical outcomes, including complete response (CR), progression-free survival (PFS) and overall survival (OS). Considerable variability was observed in the rituximab trough concentration in the first cycle (C_1-trough, 1.16-55.52 μg/ml) in patients with different lymphoma subtypes. Patients with "double-hit" lymphoma (4.01 ± 0.77 μg/ml) or mantle cell lymphoma (MCL; 15.65 ± 16.45 μg/ml) had much lower C_1-trough and worse outcomes. Great individual variation in the C_1-trough existed among patients with mucosa-associated lymphoma (MALT), and the high C_1-trough observed in patients treated with the RB regimen was associated with a better response than was obtained with R-CHOP (38.41 ± 14.13 μg/ml vs 15.49 ± 8.80 μg/ml, p = 0.0029). Despite the high aggressiveness of the cancer, Burkitt lymphoma patients receiving intensive chemotherapy had the highest C_1-trough (28.85 ± 9.35 μg/ml) and maintained long-term PFS. The C_1-trough in patients with mixed, unclassifiable B-cell lymphoma was close to 20 μg/ml, and these patients had acceptable outcomes. Overall, a low rituximab C_1-trough was associated with adverse consequences, including persistent progression, early recurrence and a short OS, however, some high-risk factors appeared to be balanced by the presence of a high C_1-trough. Basal levels of circulating CD19⁺ lymphocytes differed between and within patients with diverse lymphoma subtypes and were negatively correlated with C_1-trough. Therefore, the traditional doses of rituximab are inadequate for patients with "double-hit" lymphoma and MCL. Increasing the initial rituximab dose according to the disease, high-risk factors and even the baseline CD19⁺ lymphocyte count will be new methods to optimize therapeutic regimens for patients with different lymphoma subtypes.

Rituximab exposure-response in triweekly R-CHOP treatment in DLBCL: A loading dose is recommended to improve clinical outcomes

Previous exposure-response analyses for rituximab suggest that higher rituximab concentrations were associated with an improvement in efficacy, however, clinical studies investigating a higher rituximab dose had mixed results. To further explore the exposure-response relationship of rituximab, a prospective observational analysis was performed involving 121 newly diagnosed patients with diffuse large B-cell lymphoma treated with triweekly rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). The trough concentration in the first cycle (C_1-trough ) was significantly higher in patients achieving complete response (CR) compared with patients that did not achieve CR (22.00 μg/ml vs. 16.62 μg/ml, p = 0.0016), however, this difference between the two groups disappeared in later cycles. The relationship between rituximab C_1-trough and achieving a CR was confirmed by matched-pair logistic regression analysis (odds ratio, 0.79; p = 0.0020). In addition, a higher C_1-trough (≥18.40 μg/ml) was associated with longer progression-free survival (p < 0.0001) and overall survival (p = 0.0038). The percentages of patients that did not achieve a CR and had recurrence after CR within 24 months were 35% and 22.50%, respectively, for patients with a C_1-trough less than or equal to 18.40 μg/ml, compared with 12.35% and 6.17% for patients with C_1-trough greater than 18.40 μg/ml. Disease stage was found to be the most significant influencing factor of C_1-trough , with 51.02% of patients at stage IV with an observed C_1-trough less than 18.40 μg/ml. For these advanced patients, population pharmacokinetic simulations using an established model suggest that a loading dose of 800 mg/m²  may help to improve clinical outcomes.

Patients with high-risk DLBCL benefit from dose-dense immunochemotherapy combined with early systemic CNS prophylaxis

Survival of patients with high-risk diffuse large B-cell lymphoma (DLBCL) is suboptimal, and the risk of central nervous system (CNS) progression is relatively high. We conducted a phase 2 trial in 139 patients aged 18 to 64 years who had primary DLBCL with an age-adjusted International Prognostic Index (aaIPI) score of 2 to 3 or site-specific risk factors for CNS recurrence. The goal was to assess whether a dose-dense immunochemotherapy with early systemic CNS prophylaxis improves the outcome and reduces the incidence of CNS events. Treatment consisted of 2 courses of high-dose methotrexate in combination with biweekly rituximab (R), cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP-14), followed by 4 courses of R-CHOP-14 with etoposide (R-CHOEP) and 1 course of high-dose cytarabine with R. In addition, liposomal cytarabine was administered intrathecally at courses 1, 3, and 5. Coprimary endpoints were failure-free survival and CNS progression rates. Thirty-six (26%) patients experienced treatment failure. Progression occurred in 23 (16%) patients, including three (2.2%) CNS events. At 5 years of median follow-up, failure-free survival, overall survival, and CNS progression rates were 74%, 83%, and 2.3%, respectively. Treatment reduced the risk of progression compared with our previous trial, in which systemic CNS prophylaxis was given after 6 courses of biweekly R-CHOEP (hazard ratio, 0.49; 95% CI, 0.31-0.77; P = .002) and overcame the adverse impact of an aaIPI score of 3 on survival. In addition, outcome of the patients with BCL2/MYC double-hit lymphomas was comparable to the patients without the rearrangements. The results are encouraging, with a low toxic death rate, low number of CNS events, and favorable survival rates. This trial was registered at www.clinicaltrials.gov as #NCT01325194.

Rituximab is highly effective in children and adolescents with Burkitt lymphoma in Risk Groups R2 to R4

Data regarding the use of rituximab in children and adolescents with Burkitt's lymphoma (BL) is limited. This study retrospectively analyzed the effect of rituximab on children and adolescents with BL in risk group (R) 2 to R4. Patients underwent chemotherapy according to the revised NHL-BFM-95 protocol. Rituximab was administered at the dose of 375 mg/m² on day 0 of each cycle. A total of 106 patients were included. Stratified by the number of doses of rituximab, there were 49, 16, and 41 patients in group 1 (no rituximab), group 2 (1-3 doses of rituximab) and group 3 (≥4 doses of rituximab), respectively. The 3-year event-free survival (EFS) rates were 83.2% (95% CI = 72.6%-93.8%), 81.2% (95% CI = 52.3%-93.5%) and 96.8% (95% CI = 78.8%-99.6%) in group 1, group 2 and group 3, respectively (p = 0.077). In R2/R3, the relapse rates were 0 in patients treated with rituximab and 11.8% in those treated without rituximab (p = 0.516). In R4, the relapse rates were 18.8%, 21.4% and 3.0% in group 1, group 2 and group 3, respectively (p = 0.048). Rituximab is highly effective in children and adolescents with BL in R2 to R4. The optimal number of doses was 4-6 in patients with BL in R4.

Late relapse in patients with diffuse large B-cell lymphoma: impact of rituximab on their incidence and outcome

Diffuse large B-cell lymphoma (DLBCL) constitutes 25-35% of all non-Hodgkin lymphomas in Western countries. Approximately two thirds of the patients can be cured with standard immuno-chemotherapy. Most relapses occur within 1-2 years from diagnosis, however, the occurrence of relapses after 5 years or more has been described. We aimed at defining the incidence and clinical features of late relapses. Data of 1113 DLBCL patients were analysed. Among the 196 patients relapsing after a first complete remission, 36 (18% of relapses and 3% of all DLBCLs) experienced a recurrence more than 5 years from diagnosis. Late relapsing patients, in comparison with those relapsing earlier, showed a more favourable risk profile at presentation: normal lactate dehydrogenase levels (P = 0·002), early Ann Arbor stage (P = 0·006) and low International Prognostic Index (P = 0·003). The risk of late relapse was lowered by the introduction of rituximab as part of the front-line treatment (P < 0·001). Cause-specific survival (CSS) from the time of relapse was significantly better for late relapsing patients compared to those relapsing early: 5-year CSS rates were 53% and 31%, respectively (P = 0·033). A trend toward a better overall survival was also observed, with 5-year rates after relapse of 47% and 25%, respectively (P = 0·054).