Phase II study of Rituximab combined with THP-COP as Wrst-line
therapy for patients younger than 70 years with diVuse large B cell
lymphoma

Abstract
Introduction We previously described the eVectiveness of the THP-COP regimen comprising cyclophosphamide, pirarubicin (tetrahydropyranyl adriamycin; THP), vincristine and prednisolone in patients with diVuse large B-cell lymphoma (DLBCL). The anthracycline drug THP was apparently less cardiotoxic than doxorubicin. However, that study was completed before rituximab was introduced into clinical practice. We conducted a phase II study to determine the eVectiveness of a regimen incorporating rituximab (R-THP-COP) against DLBCL.
Patients Six to 8 courses of the regimen were administered every 2 weeks in 48 patients who were younger than 70 years.
Results The complete remission rate was 92%, the 3-year overall survival rate was 83% and 3-year progression free survival rate was 74%. No deaths were associated with the treatment regimen.
Conclusion We conclude that R-THP-COP regimen is very eVective against DLBCL. The results of our study urge randomized trials of R-CHOP and R-THP-COP among patients with CD20+ DLBCL.
Keywords Non-Hodgkin’s lymphoma · Pirarubicin · R-CHOP · R-THP-COP
Introduction
Rituximab, a chimeric monoclonal antibody against the CD20 B cell antigen, combined with the CHOP regimen has raised the complete response (CR) rate and prolonged eventfree-and overall survival (OS) in previously untreated elderly patients with DLBCL (CoiYer et al. 2002; Fisher and Shah 2003). Thus, a combination of rituximab and CHOP (R-CHOP) is currently the standard treatment for DLBCL.
The doxorubicin (DOX)-derived anthracycline, THP, is apparently less cardiotoxic than DOX (Umezawa et al. 1979; Takagi and Oguro 1987; Miller and Salewski 1994).
Accordingly, elderly patients with NHL have been treated (Kitamura and Takaku 1990; Niitsu and Umeda 1997; Mori et al. 2005) with a THP-COP regimen (Tsurumi et al. 2004) comprising THP, cyclophosphamide (CPA), vincristine (VCR), and prednisolone (PSL).
We demonstrated that the therapeutic eVectiveness of THP-COP and CHOP regimens is similar in patients with diVuse large B cell lymphoma (DLBCL) before the clinical introduction of rituximab (Tsurumi et al. 2007).
We tested the feasibility of the R-THP-COP regimen as a Wrst-line therapy by evaluating response rates, survival and toxicity in a phase II study of patients with CD20+DLBCL. We also identiWed possible demographic and clinical factors that could aVect the therapeutic outcome of R-THP-COP regimen.
Patients and methods Study design This open, non-randomized, multicenter, phase II trial was organized by Gifu University Graduate School of Medicine (Gifu, Japan). The primary objective was to assess the eVect of R-THP-COP from response rates and the secondary objective was to assess the OS and drug safety. The ethics committee of each institution approved the study and all patients provided written, informed consent in accordance with our institutional guidelines and the Declaration of Helsinki before enrollment. Adverse eVects were graded according to the National Cancer Institute Common Toxicity Criteria version 2.0 and recorded as the maximum grade during the period from initiation of the Wrst course until recovery from the Wnal course of chemotherapy.
Patients
Adults aged between 18 and 70 years were eligible for inclusion in the study if diagnosed with untreated CD20+DLBCL from biopsies and classiWed according to the most recent World Health Organization classiWcation (JaVe et al. 2001). All patients had clinical stage (CS) II, III, or IV DLBCL according to the Ann Arbor staging system (Carbone et al. 1971). Staging was based on clinical Wndings and tumor measurements obtained before excisional biopsy. Bulky disease was deWned as a mediastinal mass with a maximum diameter exceeding one-third of the maximum chest diameter, or any other mass that was ¸10 cm.
None of the patients was infected with human immunodeWciency virus or human T cell lymphotropic virus type I.
All patients had evaluable lesions at entry and underwent periodic assessments as follows: physical examination;chest radiology; computed tomography of the brain, neck, chest, abdomen and pelvis; bone marrow aspiration and biopsy; gallium scintigraphy, and/or Xuorodeoxyglucose positron emission tomography (FDG-PET) and laboratory measurements of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin, alkaline phosphatase (ALP), creatinine, lactate dehydrogenase (LDH), soluble interleukin-2 receptor (sIL-2R), C-reactive protein (CRP), and peripheral blood cell counts. All patients had normal cardiac function (left ventricular ejection fraction of >50%), serum creatinine <2.0 mg/dL, no severe complications, and no multiple malignancies. Their performance status (PS) ranged from 0 to 4.
Treatment strategy
The R-THP-COP regimen comprised 375 mg/m2 of rituximab given as a 24 h continuous intravenous (i.v.) drip infusion on day 1; 750 mg/m2 of CPA given as a 2 h i.v. drip infusion on day 3; 50 mg/m2 of THP given as a 30 min i.v. drip infusion on day 3; 1.4 mg/m2 (maximum dose 2.0 mg) of VCR given i.v. in a bolus over 5 min on day 3 and 100 mg of oral (p.o.) PSL on days 3–7. Six to eight courses were administered every 2 weeks. A 5-HT3 receptor antagonist prevented nausea and vomiting. Cardiac function was echocardiographically evaluated before and after every two courses of chemotherapy. Granulocyte colony-stimulating factor (G-CSF) was administered subcutaneously (s.c.) at 2
g/kg when the peripheral neutrophil count was <1 £ 109 cells/L. Patients with a bulky mass received radiotherapy ranging from 30 to 40 Gy after chemotherapy. The daily radiotherapy dose varied from 1.8 to 2.0 Gy. Patients who relapsed or whose disease progressed after R-THP-COP,and those who were resistant to R-THP-COP underwent salvage chemotherapy with R-P-IMVP-16/CBDCA (rituximab,methylprednisolone, ifosfamide, methotrexate, etoposide, and carboplatin) (Sawada et al. 2002).
End points
The primary end point was deWned as response rate after chemotherapy and was categorized after repeated physical examination, radiological studies, gallium scintigraphy or FDG-PET, bone marrow aspiration or biopsy, according to the criteria deWned by Cheson et al. (1999).
Secondary end points were OS and toxicity. OS was measured from the time of assignment to treatment until death from any cause. Progression-free survival (PFS) for all eligible patients, including non-responders, was taken as the interval from the day of starting chemotherapy to the day on which progression or death due to any cause occurred. Patients who received autologous peripheral blood stem cell transplantation were censored at the end of transplantation.
Statistical analysis The sample size for the study was calculated from a predicted response rate of 65% and a minimum of 45% with an alpha error of 0.05 and a beta error of 0.20 using Simon’s two-stage minimax design (Simon 1987). The estimated sample size was 43 plus a further 10% of predicted ineligible patients.
All follow-up data were updated on 30 June 2008.
Patient characteristics were compared using the Chisquared test. The eVects of several pretreatment factors on achieving CR or PR were analyzed using the Chi-squared test. The eVects of several pretreatment factors on survival were examined by univariate analyses using the log-rank test based on the method of Kaplan and Meier (Kaplan and Meier 1958). Multivariate analysis using Cox regression deWned the prognostic signiWcance of selected covariates (Cox 1972).
Results
Patient characteristics
All of 48 consecutive candidate patients (25 males and 23 females) presenting between 1 April 2003 and 31 December 2006 were eligible to participate and were enrolled in the study. Table 1 shows that the clinical characteristics did not signiWcantly diVer between this patient population and those in our previous study (data not shown).

Response to therapy
Table 2 summarizes the responses to therapy. Responses of all 48 patients could be evaluated, and 44 (92%) of them reached CR or CRu. The rates of CR/CRu were signiWcantly lower in patients with high sIL-2R (¸2,000 U/ml) and also in those with a poor International Prognostic Index (HI/H) (A predictive model for aggressive non-Hodgkin’s lymphoma 1993).
Survival rates
The median follow-up was 37 months and the OS rate was 83% after 3 years (Fig. 1a). The PFS rate was 74% after 3 years with a median PFS duration of 36 months (Fig. 1b).
The OS rate did not diVer signiWcantly in accordance with IPI. SigniWcant factors associated with a worse OS were advanced CS, presence of B symptoms and higher sIL-2R (Table 2). The 3-year PFS signiWcantly diVered in accordance with IPI. Other signiWcant factors associated with a worse PFS were extranodal sites (>1), advanced CS, poor PS, presence of B symptoms and higher sIL-2R (Table 3).

Toxicity
Table 4 summarizes the adverse eVects of this regimen.
Hematological toxicity in 48 patients comprised 16 (33%), 35 (73%), and 7 (15%) with grade 3 or 4 anemia, neutropenia, and thrombocytopenia, respectively. The non-hematologic adverse eVects were almost always tolerable. Table 5 summarizes the change of cardiac function. There is no signiWcant diVerence of cardiac function between before and after chemotherapy. Grade 3 cardiac and pulmonary toxicity developed in one patient with normal cardiac function before entering the study. The left ventricular ejection fraction conWrmed the recovery of cardiac function. Excessive volume might have been responsible for the cardiac and pulmonary toxicity in this patient. None of the patients died due to causes related to the treatment regimen.

Discussion
Since the 1993 report published by Fisher et al. (1993), CHOP therapy has been considered the gold standard for DLBCL. Thereafter, the therapeutic eYcacy improved little although the frequency of infections has decreased due to the use of G-CSF (Bertini et al. 1994, 1996; Niitsu and Umeda 1997; Doorduijn et al. 2003). Pfreundschuh et al.
(2004) reported that reducing the CHOP interval from 3 to 2 weeks (CHOP-14) improves outcomes. Combining rituximab with the CHOP regimen (R-CHOP) resulted in a signiWcant advance (CoiYer et al. 2002; Fisher and Shah 2003). The RICOVER-60 (rituximab with CHOP for patients aged >60 years) trial of the German High-Grade

Non-Hodgkin’s Lymphoma Study Group (DSHNHL) showed that a combination of both approaches (R-CHOP-14) could further improve the prognosis of elderly patients with NHL (Pfreundschuh et al. 2008a, b). The MabThera International Trial Group (MInT) described the eVect of a rituximab combination among young patients (Pfreundschuh et al. 2008a, b). Thus, a combination of rituximab and CHOP (R-CHOP) or R-CHOP-14 might become the standard treatment for DLBCL.
Because it is apparently less cardiotoxic than DOX (Umezawa et al. 1979; Takagi and Oguro 1987; Miller and Salewski 1994), the beneWcial eVect of the DOX-derived THP has been assessed mainly in elderly lymphoma patients. Kitamura and Takaku (1990) showed that the THP-CVP regimen, which contains THP instead of DOX, safely and eVectively treated patients aged ¸65 years with NHL. Aoki et al. (1998) also showed that chemotherapies containing THP are useful and safe for elderly patients with NHL and that the results of such regimens are superior to those of DOX. We also described the eVect of the THPCOP regimen in patients with DLBCL (Tsurumi et al. 2007). Based on these results, the combination of rituximab and THP-COP (R-THP-COP) should also be tested for patients with CD20+ DLBCL.

The present study found that the eVects, feasibility and toxicity of the R-THP-COP regimen were similar to those of R-CHOP. The CR rate of 92% and the 3-year OS rate of 83% were better than those in our previous THP-COP study. The frequency of non-hematological (except cardiac) adverse eVects of R-THP-COP was similar to that of R-CHOP, whereas that of hematological toxicity induced by R-THP-COP was higher. Cardiac function evaluated by echocardiography during our study was not damaged throughout the period of R-THP-COP administration. One patient developed a cardiopulmonary disorder but completed the regimen, and causality related to THP remains unknown.
Rituximab is obviously eVective against CD20+DLBCL. The results of our clinical trial justify randomized comparisons of R-THP-COP and R-CHOP regimens in a phase III trial.

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