Soluble Interleukin-2 Receptor and C-Reactive Protein Levels Are Associated with the Efficacy of Bendamustine As a Salvage Treatment for Indolent Lymphoma

Background:

Bendamustine has demonstrated a favorable efficacy and toxicity profile in relapsed or refractory indolent lymphoma. Limited information is available regarding the prognostic factors (particularly laboratory parameters) of bendamustine treatment, although studies have shown a relationship between the hampered effect of bendamustine and an increase in lactate dehydrogenase (LDH) levels. Therefore, we retrospectively evaluated clinical and laboratory factors immediately prior to initiating bendamustine treatment and analyzed its correlation with the clinical outcome among patients with relapsed or refractory indolent lymphoma.

Patients and methods:

We analyzed 55 relapsed or refractory indolent lymphoma patients who had been treated with bendamustine alone (n = 19) or rituximab plus bendamustine (n = 36) at our hospital from 2000 to 2015. The median age at diagnosis was 65 years and the median follow-up period was 552.5 days. Histological analysis revealed follicular lymphoma (n = 21), mantle cell lymphoma (n = 10), MALT lymphoma (n = 7), lymphoplasmacytoid lymphoma (n = 5), and other low-grade B cell lymphomas (n = 4). We further analyzed the relationships between the clinical outcome [overall response rate (ORR), complete response (CR), progression-free survival (PFS), and overall survival (OS)] and clinical data, including sex, patient age (≥65 years), performance status (≥2), IPI (≥HI), FLIPI (≥HI), no. of previous therapies (≥2), prior purine analogue treatment, response to last treatment, and laboratory parameters [white blood cell count (≥5000/µl), lymphocyte count (≥1000/µl), platelet count (≥10000/µl), LDH (elevated or normal), sIL-2R (elevated or normal), and CRP (elevated or normal)], before starting bendamustine treatment.

Results:

The median number of cycles of bendamustine was 4 (range: 1-8). The ORR was 80.3% with a CR of 39.2%. Moreover, the CR rate was significantly worse in patients who had elevated sIL-2R and CRP, high or high-intermediate IPI scores, and a high WBC count (P = 0.002, P < 0.001, P = 0.072, and P < 0.046, respectively). Among follicular lymphoma patients, elevated CRP was only associated with a low CR rate (P = 0.028). In multivariate analysis, sIL-2R, CRP, and a high WBC count were all significantly associated with a worse CR rate (P = 0.044, P = 0.002, and P = 0.032, respectively). The 1- and 2- year OS rates were 80.3% and 76.1%, respectively. The OS was significantly higher in a group of the patients who obtained CR after bendamustine, were treated with rituximab plus bendamustine, and did not receive prior purine analogue treatment (P = 0.007, P = 0.008, and P < 0.001, respectively). An elevated CRP was associated with worse OS (P = 0.055). In multivariate analysis, only CR after bendamustine was significantly associated with improved OS (P = 0.023).

The 1- and 2-year PFS rates were 69.2% and 60.5%, respectively. PFS was significantly better in patients who obtained CR after bendamustine treatment, had a normal CRP, had not received more than 2 previous therapies, and had a good performance status (P < 0.001, P = 0.007, P = 0.031, and P = 0.033, respectively). In multivariate analysis, any prognosis factors were significantly associated with PFS.

Conclusion:

This is the first study to demonstrate a correlation between laboratory parameters (i.e., CRP and sIL-2R) and the clinical outcome in patients with relapsed or refractory indolent lymphoma who were treated with bendamustine. In this study, CRP and sIL-2R levels as well as the WBC count were associated with the CR rate. In addition, the CRP levels were associated with OS and PFS, but LDH levels were not associated with any clinical outcomes. Previous studies have reported that the elevation of serum CRP and sIL-2R levels were associated with poor OS or PFS in patients who were treated with rituximab combined with CHOP in diffuse large B-cell lymphoma or follicular lymphoma. Our study indicates that serum CRP and sIL-2R levels are also important laboratory parameters for patients with indolent lymphoma who underwent bendamustine treatment.