Use of maintenance rituximab (R) in the United States following R-based induction for follicular lymphoma (FL).

Abstract

8100 Background: The benefits of R maintenance after R-based induction as front line therapy, and the patterns of R maintenance use for FL in the US remain undefined. Methods: The National LymphoCare Study (NLCS) is a multicenter observational study collecting data on treatment and outcomes for patients (pts) with newly diagnosed FL in the US. From 2004-2007, 2,734 pts were prospectively enrolled from 226 community and 38 academic sites. Initial treatment and maintenance/observation decisions were made by the treating clinician. Pts without progression within 215 days of completing initial induction were classified as either R maintenance or observation. Demographic and baseline disease characteristics were summarized for each group. Univariate associations between baseline factors, treatment setting, initial treatment, and R maintenance vs. observation were tested by X2. Results: Among pts receiving R-based induction, 1,046 met inclusion criteria for this analysis with a median age of 61 (range 22-97); FLIPI 0-1, 31%; 2, 31%; ≥3, 38%. Pts received initial R (n=220), RCVP (n=195), RCHOP (n=467), R-fludarabine (n=122), or R-other (n=42). After initial treatment with R alone, 54% of pts had R maintenance and 46% were observed. Following R- chemo, 45% of pts had maintenance and 55% were observed. Pts on R maintenance were more likely to have FL grade 1/2 (73% v 59%; p<0.001), stage 3/4 (81% v 70%; p=0.003), normal LDH(64% v 56%; p=0.029), >4 lymph nodes (39% v 34%; p=0.019) and ≥2 extranodal sites (27% v 19%; p=0.012). Pts in the West were more often observed (p=0.003). Pts receiving R alone vs. R-chemo were more likely to get maintenance (p=0.02). There were no differences in maintenance use by age, gender, race, or FLIPI. With median follow-up of 45 months, 257 progression events and 75 deaths have occurred. Conclusions: Following R-based induction, US practices are evenly split between maintenance R and observation. Grade 1/2, stage 3/4, and initial R alone are associated with more R maintenance use, but regional variation influences maintenance as much as other clinical factors. Results from completed phase 3 trials on R maintenance after R-based induction are needed to provide clearer standards for use. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Genentech Genentech, GlaxoSmithKline, sanofi-aventis Roche Amgen, Biogen Idec, Genentech, GlaxoSmithKline, Roche