Фолликулярная лимфома: результаты многоцентрового исследования терапии первой линии препаратами бендамустин и ритуксимаб, факторы риска неблагоприятных событий (протокол fl-rus-2013)

Background. Follicular lymphoma (FL) is the most common type of indolent lymphomas and accounts for 20–30 % of all non-Hodgkin’s lymphomas detected. High risk of recurrence and elderly patients make it difficult to choose induction therapy for FL. The R–B course in comparison with the R–CHOP course increases the progressive free survival (PFS) of FL patients and is less toxic. International studies have not studied the efficacy and toxicity of the R–B course due to various cytological types of FL. Aim of the study – assessment of the effectiveness and toxicity of the R–B course (with R support) in general and depending on the different cytological types of FL, the assessment of overall survival (OS) and PFS (adverse events: progression, relapse, death); identification of risk factors for an adverse event in general and death, in particular. The main endpoint of this study is selected BPV. Materials and methods. We performed a prospective, multicenter, open-label trial in Russia since June 1, 2013 till June 1, 2018. The study included 74 patients with FL. Median age of patients was 59 years (from 30 to 78 years). Treatment was completed in 66 patients, so this group of patients was analyzed. Ratio between men and women was 1:2. 32/66 of patients (48 %) were older than 60 years old. Patients received rituximab 375 mg/m2 on day 1 and bendamustine 90 mg/m2 on days 1 and 2 of a 4-week cycle (6 cycles). 49/66 (74 %) of patients were diagnosed with FL grade 1, 10/66 (15 %) – grade 2, 7/66 (11 %) – grade 3A. 34/66 (52 %) patients had nodular tumor growth type, 28/66 (42 %) – nodular-diffuse, 4/66 (6 %) – diffuse. High risk according to FLIPI had 25/59 (42 %) of patients with cytologic grade of FL 1–2 and 7/7 (100 %) of patients with FL grade 3A. Extranodal lesions were revealed in 26/66 (39 %) of cases: in 4/66 of cases – orbit, in 2/66 – parotid gland, in 5/66 – lungs, in 4/66 – intestines, in 2/66 – stomach, 2/66 – pancreas, 2/66 – uterus, 2/66 – skin, 1/66 – subcutaneous tissue, 3/66 – vertebrae, in 1/66 – latticed maze and nasal passages, 1/66 – kidneys, 1/66 – root of the tongue. In 23/26 (88 %) of cases extranodal lesion was revealed in generalized stage of FL (including lymph nodes and bone marrow). Extranodal lesions were found in 37 % of patients with FL grade 1–2, and 57 % with FL grade 3A. Bulky also was observed more frequently in pts with FL grade 3 3/7 (43 %) than in patients with FL grade 1–2 20/59 (34 %). (The risk factors of an adverse event are also its predictors in this study.) Results. Complete remission of disease was achieved in 40/66 (61 %) patients, partial remission – 13/66 (19 %) patients. Tumor progression observed in 11/66 (17 %) cases, patients were withdrawn from the protocol. А partial tumor response was achieved in 2/66 cases (3 %) and patients received high-dose therapy after 4 courses of R–B. Five-year (as well as the 3-year) overall survival (OS) of all patients (n = 66) in R–B was 90 % (95 % confidence interval (CI) 78–96), 5-year PFS – 70 % (95 % CI 55–85) and a 3-year PFS – 75 % (95 % CI 60–89). The cumulative incidence of relapse (considering competing risks of progression and death) at the 3th year after initiation of treatment was 11 % (95 % CI 3–19). The following independent statistically significant (p ≤0.05) predictors of PFS (measured in the onset of the disease) were determined (as a result of a stepwise multivariate cox regression analysis): 1) cytological type of tumor (only type 3A is significant); 2) involvement of nodal zones (more than 4); 3) presence of a conglomerate of tumor lymph nodes larger than 6 cm (bulky); 4) Ki-67 protein expression (more than 35 %). The first 3 characteristics (as well as the sign «presence of extranodal foci», close to the level of significance) are independent statistically significant predictors of OS. In the single factor analysis the following characteristics (besides the above) were significant: index FLIPI (significant only 5 points against all others), bone marrow damage, β2-microglobulin (more than 2.2 mg/L), age (over 68 years) and hemoglobin (less than 110 g/dL). Conclusion 1. The independent negative predictors of OS and PFS in follicular lymphoma were determined. 2. Of the predictors of an adverse event identified, the greatest risk (as a result of a multivariate analysis) is associated with a 3A cytological type of tumor. 3. The FLIPI index has a predictive value not only for the determination of OS, but also for the PFS (moreover, in reduced dichotomous form: 5 points against all the others combined). 4. An increase in the time interval between the first manifestations of follicular lymphoma (lymph node enlargement / appearance of a tumor formation) and the start of therapy beyond a certain threshold value (estimated to be approximately 22 months) is associated (according to the results of univariate analysis) with an increased risk of an adverse event. One of the reasons for the increase in this time interval is associated with expectant medical tactics adopted during the slow development of the clinical picture of the disease. The obtained result shows that the low rate of development of the clinical picture of the disease does not correlate with the low risk of adverse events, and, therefore, cannot be a determining factor when deciding whether to start treatment. 5. The morphology of the tumor is the determining factor in the choice of induction therapy. 6. After achieving full/partial remission of FL, there is a constant risk of recurrence of the disease (by the age of 3 from the termination of treatment, the risk is 11 % (95 % CI 3–19)). 7. The R–B course effectively sanitizes the bone marrow. 8. The R–B allows performing stem cells mobilization and autoSCT that is actual in FL patients with bone marrow involvement. 9. The treatment regimen of R–B is effective and has a relatively low toxicity, so it is advisable in the treatment of elderly patients.