Hüttmann A, Rekowski J, Müller SP, Hertenstein B, Franzius C, Mesters R, Weckesser M, Kroschinsky F, Kotzerke J, Ganser A, Bengel FM, La Rosée P, Freesmeyer M, Höffkes HG, Hertel A, Behringer D, Prange-Krex G, Griesshammer M, Holzinger J, Wilop S, Krohn T, Raghavachar A, Maschmeyer G, Brink I, Schroers R, Gaska T, Bernhard H, Giagounidis A, Schütte J, Dienst A, Hautzel H, Naumann R, Klein A, Hahn D, Pöpperl G, Grube M, Marienhagen J, Schwarzer A, Kurch L, Höhler T, Steiniger H, Nückel H, Südhoff T, Römer W, Brinkmann M, Ose C, Alashkar F, Schmitz C, Dürig J, Hoelzer D, Jöckel KH, Klapper W, and Dührsen U
Standard first-line treatment of aggressive B cell lymphoma comprises six or eight cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus eight doses of rituximab (R). Whether adding two doses of rituximab to six cycles of R-CHOP is of therapeutic benefit has not been systematically investigated. The Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL) trial investigated the ability of [ 18 F]-fluorodesoxyglucose PET scanning to guide treatment in aggressive non-Hodgkin lymphomas. Patients with B cell lymphomas and a negative interim scan received six cycles of R-CHOP with or without two extra doses of rituximab. For reasons related to trial design, only about a third underwent randomization between the two options. Combining randomized and non-randomized patients enabled subgroup analyses for diffuse large B cell lymphoma (DLBCL; n = 544), primary mediastinal B cell lymphoma (PMBCL; n = 37), and follicular lymphoma (FL) grade 3 (n = 35). With a median follow-up of 52 months, increasing the number of rituximab administrations failed to improve outcome. A non-significant trend for improved event-free survival was seen in DLBCL high-risk patients, as defined by the International Prognostic Index, while inferior survival was observed in female patients below the age of 60 years. Long-term outcome in PMBCL was excellent. Differences between FL grade 3a and FL grade 3b were not apparent. The results were confirmed in a Cox proportional hazard regression model and a propensity score matching analysis. In conclusion, adding two doses of rituximab to six cycles of R-CHOP did not improve outcome in patients with aggressive B cell lymphomas and a fast metabolic treatment response.