Rituximab Improves Paclitaxel/ Topotecan Salvage Efficacy in NHL

O R L A N D O - A d d i n grituximab (Rituxan) to paclitaxel(Taxol)/topotecan (Hycamtin) salvagetherapy raises response rates byabout 25%, more than triples completeresponse rates, and is effectivein both primary refractory and relapsedaggressive B-cell lymphomas.Phase II Study
Anas Younes, MD, and colleaguesfrom M.D. Anderson Cancer Centerreported data from a 45-patient phaseII study of the paclitaxel/topotecan/rituximab regimen in a poster presentationat the 43rd Annual Meetingof the American Society of Hematology(abstract 1456)."We concluded that rituximabimproves the response rate ofpaclitaxel/topotecan and increasesthe proportion of complete remissions.There was not a significantlydifferent toxicity profile with theaddition of rituximab. However, thisis not frontline treatment yet," Dr.Younes told ONI in an interview.The study enrolled 45 patientswith relapsed or refractory aggressivenon-Hodgkin's lymphoma(NHL) and included 34 with diffuselarge cell, 4 with follicular large cell,and 7 with transformed disease.Twenty patients (44%) had primaryrefractory disease, and 25 (56%) hadrelapsed after responding to previoustherapy. Most patients had receivedonly a single previous regimen,and 15 (33%) had receivedprior cytarabine/platinum. The medianage was 58.Complete
response rates
increased from
6% to 25%The regimen included paclitaxel200 mg/m2 IV given over 3 hourson day 1, topotecan 1 mg/m² IVgiven each day on days 1 to 5, andrituximab 375 mg/m² given 1 daybefore each paclitaxel/topotecancourse. All patients also receivedprophylactic filgastrim (G-CSF,Neupogen). Courses were repeatedevery 3 weeks, and patients receiveda median of 31% Dr. Younes hadreported in a previous study ofpaclitaxel/topotecan in a similargroup of patients.The quality of response also improveddramatically, with completeresponses rising from 6% withpaclitaxel/topotecan to 25% withthe three-drug regimen.The combination had similar effectsin patients who had relapsedafter initially responding to therapy.Adding rituximab increased the responserate to 80% from the 65%seen previously with paclitaxel/topotecan, and increased the completeresponse rate from 18% to 60%.Toxicity
"Toxicity was comparable to whatwe had seen with paclitaxel/topotecanalone," Dr. Younes said. A total of159 cycles of therapy were delivered.Neutrophil counts of less than500/?L were observed after 66 cycles(42%), and platelets below 10,000/μLafter 16 cycles (10%). There were noserious nonhematologic toxicities.Febrile neutropenia occurred in 7 of45 patients (16%).