Phase II study of CVP followed by tositumomab and iodine I 131 tositumomab (Bexxar therapeutic regimen) in patients with untreated follicular non-Hodgkin's lymphoma (NHL)

Abstract

6520 Background: A phase II, open-label, multicenter study was conducted to determine the efficacy of Bexxar therapy following CVP in pts with previously untreated follicular NHL. Methods: Pts received cyclophosphamide (400 mg/m2, days 1–5), vincristine (1.4 mg/m2, day 1), and prednisone (100 mg/m2, days 1–5) followed by Bexxar therapy (65 or 75 cGy total body dose). Treatment with CVP was repeated every 21 days for 6 cycles followed by Bexxar therapy within 56 days. The primary endpoint was overall response (CR, CRu, PR). Secondary endpoints were CR, duration of response, progression-free survival (PFS), and safety. Pts with untreated, stage III/IV or bulky stage II, follicular NHL were enrolled from Feb 2000 to Jan 2001. Inclusion/exclusion criteria were similar to previous Bexxar therapy studies. Results: All enrolled pts (n = 30) completed all therapy and were included in the analysis. Median age was 52 yrs (range, 34–72 yrs). Histology: 77% follicular grade 1, 17% follicular grade 2, 7% follicular unclassified. The majority (97%) of pts had stage 3/4 disease and 50% had a maximum tumor diameter ≥ 5.0 cm. Following CVP 100% pts had a response (50% CR; 50% PR). Following Bexxar therapy, 9 of 15 pts converted from PR to CR. With a median follow-up of 2.3 yrs from start of therapy, median PFS has not been reached, and 23 (77%) pts continue in response for 0.6 to 3.4 yrs. Following Bexxar therapy, grade 4 neutropenia and thrombocytopenia occurred in 33% and 23% pts, respectively; there were no serious infections; 1 patient has developed AML; and there were no reported cases of conversion to HAMA positivity. Conclusions: Treatment of pts with newly diagnosed follicular NHL with CVP followed by the Bexxar therapeutic regimen produced an overall response rate of 100% and a CR rate of 80%. Among pts who achieved less than a CR with CVP, 60% achieved a CR after Bexxar therapy. With a median follow-up of 2.3 yrs, 77% of pts continue in response. This study suggests that CVP/Bexxar is a promising therapeutic regimen for patients with previously untreated, advanced-stage, follicular NHL. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Corixa; GlaxoSmithKline