Subanalysis of the StiL NHL 1–2003 Study: Achievement of Complete Response with Bendamustine-Rituximab (B-R) and CHOP-R in the First-Line Treatment of Indolent and Mantle Cell Lymphomas Results in Superior Survival Compared to Partial Response.

Abstract 2724 Background: The NHL 1 study, a prospective, multicenter, randomized, phase 3 study which compared B-R and CHOP-R as first-line treatment in indolent lymphomas and mantle cell lymphoma (MCL), demonstrated a significant benefit in progression-free survival (PFS) as well as improved tolerability for B-R compared with CHOP-R. Here we present an analysis of the impact of response quality on outcome. Methods: 514 patients (pts) with indolent or MCL were randomized to receive B-R or CHOP-R for a maximum of 6 cycles. Results: The overall response rate in the 514 pts (261 B-R; 253 CHOP-R) was 92.7% and 91.3% in the B-R and CHOP-R arms, respectively (as presented at the last ASCO meeting, J Clin Oncol 30, 2012 (suppl; abstr 3). A complete response (CR) was observed in 39.8% in the B-R arm and in 30% in the CHOP-R arm (p=0.021). The achievement of CR was associated with a significantly prolonged PFS and overall survival (OS) (Table 1). Analysis by treatment arm revealed a trend for superior PFS and a significantly improved OS for patients achieving CR following treatment with B-R. In the CHOP-R arm, patients in CR had a significantly superior PFS compared to those in PR with a trend to superior OS. Regardless of the quality of response, PFS was superior with B-R versus CHOP-R: For patients in CR, the median PFS was not reached with B-R, whereas for CHOP-R it was 53.7 months (p=0.0204). In patients achieving PR, treatment with B-R resulted in a median PFS of 57.2 months, and this was 30.9 months with CHOP-R (p=0.0002). We noted a statistically significant difference in CR rates between male (n=272, median age 63 years) and female (n=242, median age 64 years) patients. The CR rate was 28.6% in male patients and 42.1% in female patients (p=0.0016). Female patients had a longer median PFS (51.4 months) compared to male patients (38.6 months), however, this difference was not statistically significant (p=0.0866). Conclusions: Patients in CR following first-line treatment in our study had a significantly longer PFS and OS compared to those achieving a PR. Therefore, our results strongly suggest an association between quality of response and outcome. Disclosures: No relevant conflicts of interest to declare.