A phase 1 dose escalation study of bortezomib combined with rituximab, cyclophosphamide, doxorubicin, modified vincristine, and prednisone for untreated follicular lymphoma and other low-grade B-cell lymphomas.

Abstract

Bortezomib has demonstrated efficacy in patients with relapsed B-cell non-Hodgkin lymphoma (NHL) both alone and in combination with other agents; however, limited data exist regarding its toxicity in combination with common frontline therapies for indolent NHL. A phase 1 study of bortezomib combined with rituximab, cyclophosphamide, doxorubicin, modified vincristine, and prednisone (R-CHOP) was conducted in patients with untreated follicular lymphoma (FL) and other indolent NHLs. Nineteen patients, including 10 patients with FL, were enrolled. The median patient age was 59 years (range, 29-71 years). Seven patients had a FL International Prognostic Index score ≥3. R-CHOP with the vincristine dose capped at 1.5 mg was administered on a 21-day cycle for 6 to 8 cycles, and 1 of 3 dose levels of bortezomib (1.0 mg/m(2) [n = 1], 1.3 mg/m(2) [n = 6], or 1.6 mg/m(2) [n = 12]) was administered on days 1 and 8 of each cycle using a Bayesian algorithm for dose escalation. The maximum tolerated dose (MTD) of bortezomib with modified R-CHOP was reached at 1.6 mg/m(2). Dose-limiting toxicity was observed in 5 patients (1 patient at a bortezomib dose of 1.0 mg/m(2), 1 patient at a bortezomib dose of 1.3 mg/m(2), and 3 patients at a bortezomib dose of 1.6 mg/m(2)). Neuropathy occurred in 16 patients (84%), including 2 patients (11%) who experienced grade 3 sensory neuropathy. Grade 4 hematologic toxicity occurred in 4 patients. Of 19 evaluable patients, 100% responded, and the complete response rate was 68%. At a median follow-up of 32 months, the 3-year progression-free survival rate was 89.5%. Bortezomib combined with modified R-CHOP produced high response rates without substantial increases in toxicity. A phase 2 study of R-CHOP and bortezomib given at this established MTD is currently ongoing.