A Phase I/II Trial of Lenalidomide and RCHOP (R2CHOP) in Patients with Newly Diagnosed Diffuse Large B -Cell (DLBCL) and Follicular Grade 3 Lymphoma.

The addition of rituximab to chemotherapy significantly improved the results of therapy in aggressive non-Hodgkin's B cell lymphoma (NHL). However, significant number of the patients relapse following initial therapy. Lenalidomide was shown to have significant single agent activity in relapsed aggressive B cell lymphoma (J Clin Oncol 26:4952-7, 2008) however the safety in combination with standard first line immunochemotherapy is unknown. We initiated a phase I/II trial of R2-CHOP (cyclophosphamide, vincristine, doxorubicin, prednisone rituximab and lenalidomide) to establish the safety and efficacy of this therapy in the treatment of patients with newly diagnosed aggressive B cell NHL. Herein, we report the results of phase I portion of this study.

A phase I study was designed to define the maximum tolerated dose (MTD) of lenalidomide administered on days 1-10 with R-CHOP chemotherapy (rituximab 375 mg/m2, cyclophosphamide 750 mg/m2, doxorubicin 50mg/m2, vincristine 1.4 mg/m2, all on day 1, prednisone 100 mg/m2 days 1-5 of 21 day cycle) utilizing 3+3 dose escalation design. Lenalidomide dose escalation levels were 15 mg, 20 mg and 25 mg. All patients received 6 mg pegfilgrastim injection on day 2. Dose limiting toxicity (DLT) was defined as any grade 3 or more non-hematological toxicity or a hematological toxicity requiring a delay of the next cycle of chemotherapy due to cytopenia. The latter criterion was to ensure maintenance of the dose intensity and schedule of RCHOP; a potentially curative therapy in this setting. Eligible patients were adults newly diagnosed with CD20 positive diffuse large cell or follicular grade III B cell lymphoma, ECOG PS 0-2 and good organ function. There was no upper age restriction to participate in this study.

Twelve patients were enrolled in phase I of this study. The median age was 69 years (range, 49-82) and 58% (7/12) of patients were males. Ten patients (83%) had DLBCL and two (17%) patients had follicular grade 3B lymphoma. International prognostic index was intermediate, high- intermediate and high in 6, 4 and 2 patients respectively. Patients distribution by lenalidomide dose was: 3 patients received 15 mg/day, 3 received 20 mg/day and 6 received 25 mg/day on days 1-10. Non-hematological toxicities included: grade 3 toxicity - neuropathy in one patient (8.3%), grade 2 toxicities were: infection in 17% (2/12) patients (skin in one patient, otitis media, and urinary tract infection in one patient); nausea 8% (1/12), rash 8% (1/12) and alopecia 41% (5/12). The most common toxicity to R2-CHOP was myelosuppresion. Grade 3 and 4 neutropenia occurred in 17% (2/12) and 41% (5/12) of patients, respectively. The neutropenia was of short duration, and no patients developed neutropenic complications. Grade 3 thrombocytopenia was seen in 8% (1/12). Most importantly, there were no delays in chemotherapy due to cytopenias. No DLT was seen. The 25 mg/day days 1-10 dose of lenalidomide was taken forward to an ongoing phase 2 trial.

Lenalidomide at a dose of 25 mg/day for days 1- 10 combined with R-CHOP chemotherapy is well tolerated. The addition of lenalidomide did not affect hematological recovery and did not result in treatment delays. This dose and schedule is now being evaluated in the phase II part of the trial.

Zent:Genentech, Bayer, Genzyme, Novartis: Research Funding. Witzig:Novartis: Research Funding.