Thiotepa, rituximab improve response in CNS lymphoma

The investigators also analyzed activity according to IELSG risk.

“Arm C was significantly more active in all the 3 subgroups,” Dr Ferreri observed, “and importantly, the overall response rate and complete remission rate were similar for each arm in the 3 different risk groups.”

Second randomization and survival

One hundred and eighteen patients went on to a second randomization, 35 from arm A, 35 from arm B, and 48 from arm C.

Fifty-nine patients were randomized to the whole-brain radiotherapy cohort, and 59 to the carmustine-thiotepa-autologous stem cell transplant cohort.

At a median follow-up of 21 months, 110 patients remain failure free, 32% from arm A, 54% from arm B, and 65% from arm C. Failure in 97% of the cases was due to primary site involvement, usually the brain.

Fifty-six percent of the patients are still alive, 39% in arm A, 59% in arm B, and 69% in arm C.

Ninety-seven patients died, 73 from lymphoma, 15 from toxicity of the first-line treatment, 2 from toxicity of the salvage regimen, 2 from neurotoxicity, and 5 from other causes.

Dr Ferreri concluded that the MATRIX regimen—the addition of rituximab and thiotepa to methotrexate and cytarabine—was associated with significant improvements in CR rate, ORR, and progression-free and overall survival.

The addition of rituximab and thiotepa did not increase toxicity, with the exception of greater hematologic adverse events, nor did the drugs increase the rates of severe complications. The agents also allowed for high rates of successful stem cell collection.