Final results of a randomized trial comparing 1, 3, or 6 infusions of Rituximab plus 6 cycles CHOP provide valuable preliminary data towards a more cost‐effective and safer treatment of advanced follicular lymphoma
Authors: F. McClanahan, T. Hielscher, M. Rieger, M. Hensel, M. Bentz, I. Schmidt‐Wolf, A. Käbisch, H. Salwender, H. Dürk, H. Staiger, T. Mandel, K. Neben, J. Hillengass, E. Leo, A. Krämer, A.D. Ho, M. Witzens‐Harig
Journal: American Journal of Hematology (2012)

Final results of a randomized trial comparing 1, 3, or 6 infusions of Rituximab plus 6 cycles CHOP provide valuable preliminary data towards a more cost-effective and safer treatment of advanced follicular lymphoma Rituximab has revolutionized the treatment of follicular lymphoma (FL). Although there is data supporting its use in maintenance therapy, it has never been established by randomized trials how much Rituximab is needed in first-line treatment. We report the final results of a study that randomized 126 patients with advanced-stage untreated FL between 1, 3, or 6 doses Rituximab with CHOP. Endpoints were differences in molecular remission, clinical remission, EFS, OS, and toxicity between the treatment arms. Among 99 patients analyzed in an intention-to-treat approach, 28% were PCR negative before treatment. There was no significant difference of clinical remission rates, EFS, OS, or toxicity. While the lack of significance might be explained by lack of power, the application of one dose seems to be inferior to three or six in terms of disease control and survival from a descriptive point of view. Treatment results with three and six courses seem to be equivalent to one another. With health-care systems worldwide being affected by high economic pressure, we provide unique preliminary data that less Rituximab may have a therapeutic effect without jeopardizing the success of treatment (trial registration: ISRCTN47525145). Several phase II and III clinical trials demonstrated significant activity of Rituximab as a single agent or in combination with alkylating agent-based chemotherapy in pretreated and previously untreated patients with FL [1-9]. In addition, Rituximab maintenance therapy has been shown to be effective after first-line therapy [10, 11] and in relapsed FL [12-14]. Several studies have investigated the level of molecular clearance achieved by single Rituximab and combination therapy in FL [7, 15-19], but the value of postinduction bcl-2/IgH mbp levels in bone marrow or peripheral blood samples for decisions on subsequent therapy for relapsed/resistant FL is discussed controversially [20]. In our study, 126 FL patients were randomized to receive 1, 3, or 6 doses Rituximab with CHOP chemotherapy as front line treatment. In 2004, an interim analysis showed that accrual was slower than intended but not violating premature termination protocols [21]. Major inclusion criteria were violated in 22 patients (differing reference histology n = 6, early stage n = 4, treatment not first-line treatment n = 8, missing/withdrawn informed consent n = 4, irretrievable documentation n = 4, other n = 1). Therefore, 99 patients form the base for an intend-to-treat analysis. 28 patients were PCR negative before treatment, and initial PCR-status was missing in 17, leaving 54 patients with a positive PCR-status. Of these, 26 did not have a PCR follow-up status. The presenting characteristics of all patients and among treatment arms are summarized in Table I. Molecular Remission Rate. The number of patients being evaluable for this stayed far behind the required sample size, especially as almost 30% of patients were PCR negative before treatment. Therefore, results regarding the primary endpoint are strongly biased, and neither the question whether a higher molecular remission rate can be achieved by multiple applications nor the duration of molecular remission could be answered Clinical Remission Rates and Remission Duration. After completion of immunochemotherapy, 29 of 99 patients had achieved CR and 58 PR. The proportion of patients with CR was similar in all three arms (30–34%). A total of 94% of patients had achieved at least PR (97% in arm B and C, 86% in arm A). There was a trend in clinical remission rates through different courses of Rituximab (P = 0.09). However, 3 courses were not inferior to 6 with regards to clinical remission rate. There was a nonsignificant trend of the clinical remission status between patients in arm B and C combined as compared to arm A (OR 4.86, 95% CI 0.65–56.91, P = 0.07). After a median follow-up of 60 months (range 4–90) 93 patients had achieved at least PR, with this being true for 94% of patients in each arm. Survival. After a median follow-up of 60 months (range 4–90) 39 patients relapsed or had PD (n = 16 arm A, n = 13 arm B, n = 10 arm C). Five-year EFS was 45% in arm A, 60% in arm B and 65% in arm C, with no difference between the three arms (P = 0.35; Fig. 1). Neither 3 (HR 0.67, 95% CI 0.32–1.40, P = 0.29) nor 6 courses (HR 0.58, 95% CI 0.26–1.29, P = 0.18) significantly altered EFS as compared to one course. We observed a trend towards a beneficial effect for group B and C combined compared to group A with respect to EFS (HR 0.63, 95% CI 0.33–1.20, P = 0.16; 5yrs EFS rates 61% vs. 46%), which however was not statistically significant. A total of 18 deaths were observed. The most common cause was disease progression with transformation (n = 8, of which n = 6 in arm A). Five-year OS was 72% in arm A, 82% in arm B and 80% in arm C, with no significant difference between the three arms (P = 0.46; Fig. 2). Neither 3 (HR 0.53, 95% CI 0.17–1.62, P = 0.26) nor 6 courses (HR 0.60, 95% CI 0.2–1.82, P= 0.36) significantly altered OS when compared to just one course. We observed a trend towards a beneficial effect for group B and C combined compared to group A with respect to OS (HR 0.56, 95% CI 0.22–1.42, P = 0.22; 5 yrs OS rates 86% vs. 72%), which however is not statistically significant. Kaplan-Meier graph of EFS. Five-year EFS was 45% in arm A, 60% in arm B, and 65% in arm C, with no significant difference between the three arms (P = 0.35). Kaplan-Meier graph of OS. Five-year OS was 72% in arm A, 82% in arm B, and 80% in arm C, with no significant difference between the three arms (P = 0.46). Toxicity. The most commonly observed toxicity was leucopoenia (70% of all CHOP cycles). There was no difference in infectious (P = 0.67) and allergic (P = 0.70) complications between the three arms. Although Rituximab is generally well-tolerated with a low toxicity profile, side effects of various degrees have been described [1, 22, 23]. Therefore, the amount of Rituximab to achieve optimal disease control while keeping its toxic profile minimal is an important question. In addition, health care systems worldwide are under enormous economical pressure, which justifies the need to optimize the cost-effective of cancer treatments without compromising their efficiency. In the current trial, the influence of Rituximab on mRR and duration of molecular remission is not assessable due to logistical problems, which underlines that this was an inappropriate primary study endpoint to choose. However, with almost 30% of patients being PCR negative before treatment, our data also indicates that the principle of MRD-guided treatment cannot be generalized to the entire population of FL patients. Our findings regarding the therapeutic effect are in line with previous studies [7, 8, 24, 25]. However, the lack of statistical significance of our findings might be explained by nonsufficient patient numbers and therefore lack of power, as sample size and power calculations were based on hypothesized differences in the primary endpoint. Our findings might possibly become statistically significant with larger numbers. It could be argued that sample size could be increased by modifying the exclusion process after randomization. However, we chose a set of subjects that is in full accordance to the EMEA ICH E9 guideline, and therefore conducted a valid intention-to treat analysis [26]. Previously, several trials have combined Rituximab with different chemotherapy regimens, such as CVP [8], MCP [25], CHOP [7], or Bendamustine [24]. The role of Rituximab in maintenance treatment seems to be well established by the PRIMA study [11]. Based on these studies, however, no conclusions can be drawn towards the optimal induction schedule, and the required amount of Rituximab as part of first-line therapy has never been determined. The HD2000 is the first and so far only trial that has randomized patients to receive alternative doses, and although statistical significance could not be demonstrated, our data provides good preliminary results for further studies to compare the effect of 3 versus 6 doses. Such a trial would ultimately contribute to a superior toxic profile and a cheaper and safer treatment. Patients were eligible if they had untreated, therapy-requiring CD-20 positive stage IIIa or IV FL. The diagnosis of FL was verified centrally by a reference pathologist. Study treatment consisted of six cycles standard CHOP every 3 weeks with 375 mg/m2 Rituximab. Patients were randomized to receive Rituximab once before the first cycle of CHOP (arm A), three times before the first three cycles of CHOP (arm B) or six times before each cycle of CHOP (arm C). The primary endpoint was to compare the three arms with regards to molecular remission rates after the end of treatment. Translocation t(14;18) PCR of peripheral blood and bone marrow samples among patients with positive PCR at diagnosis was performed as previously described, using nested PCR with primers specific for the t(14;18) translocation [27]. Peripheral blood samples and bone marrow aspirates were obtained before therapy and after three and six cycles. Total cellular DNA was extracted using the QIAamp DNA blood maxi kit (Qiagen). For nested PCR, the mbr of the t(14;18) translocation was amplified by a two-step nested PCR. Samples were tested as duplicates in three independent runs, and scored as PCR-positive when at least one of six reactions produced a specific amplification product. Nested PCR was shown to detect one positive cell in 105 normal cells. Potential remission probabilities were in part estimated from the literature from the pre-Rituximab era: 5 months after CHOP, a 37% mRR rate was observed [28], while after 6 cycles of R-CHOP 7 out of 8 patients converted to PCR negativity after therapy [29]. Assuming mRRs of 40% in arm A and 80% in arm C and a monotone relationship between dose and mRR, sample size and power calculations revealed that 105 PCR positive patients were required (35/arm) to answer the primary endpoint. Patients underwent CT-staging before treatment, after three and six courses, 6 months after completion of all study treatment, and after 12 months. The evaluation of CR and PR followed the recommendations by the National Cancer Institute sponsored international working group in 1998 [30]. Normal lymph node size was defined as ≤1.5cm in the longest transverse diameter for nodes >1.5cm before therapy, and ≤1cm for lymph nodes 1.1 to 1.5cm before therapy, as determined by CT-scan. Minimal Response was defined as ≤50% reduction in SPD of measurable lymphoma. The exact Cochran-Armitage test was used to examine the hypothesis of an increasing trend between number of Rituximab applications and the likelihood of remission. In case the null hypothesis of no difference among treatment groups could not be rejected, a descriptive analysis was intended to test treatment arms pair-wise for noninferiority using a confidence interval approach with a threshold of 20%. Fisher's exact test was used to examine the difference of clinical remission rates between arm A and arm B/C combined (less vs. more Rituximab). Fisher's exact test and Kruskal-Wallis test were used to examine differences among demographic and presenting characteristics at baseline. Time-to-event endpoints were analyzed with Kaplan-Meier estimates, logrank test and Cox's proportional hazard model. Patients were analyzed following the intention-to-treat principle defined by the EMEA ICH E9 guidelines “Statistical principles for clinical trials” [26]. Toxicities were graded according to WHO. All statistical tests were performed at the significance level of 0.05 for two-sided and 0.025 for one-sided tests. Analyses were carried out using “R” version 2.8, the exact Cochran-Armitage test was calculated with “SAS” version 9.1. F. McClanahan* , T. Hielscher , M. Rieger§, M. Hensel¶, M. Bentz**, I. Schmidt-Wolf , A. Käbisch , H. Salwender§§, H. Dürk¶¶, H. Staiger11, T. Mandel12, K. Neben*, J. Hillengass*, A.D. Ho*, E. Leo*, A. Krämer*, M. Witzens-Harig*, * Internal Medicine V, University of Heidelberg, Heidelberg, Germany, Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London, United Kingdom, Department of Biostatistics, German Cancer Research Centre, Heidelberg, Germany, § Onkologische Schwerpunkt Praxis, Mannheim, Germany, ¶ Onkologische Schwerpunkt Praxis, Mannheim, Germany, ** City Hospital Karlsruhe, Medicine II, Karlsruhe, Germany, Medicine I, University Hospital Bonn, Bonn, Germany, Facharztpraxis Internal Medicine, Gieβen, Germany, §§ Asklepios Klinik Altona, Medicine II, Hamburg, Germany, ¶¶ St. Marien-Hospital Hamm, Hamm, Germany, 11 Klinikum Mittelbaden, City Hospital, Baden-Baden, Germany, 12 SLK Kliniken Heilbronn, Medicine II, Bad Friedrichshall, Germany.