Safety and Clinical Activity of Temsirolimus in Combination with Rituximab and DHAP in Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma - Results of the Part I Cohort of the STORM Trial

Purpose.

To evaluate the safety, tolerability and efficacy of the combination of the mTOR inhibitor Temsirolimus and a standard salvage regimen (R-DHAP) in patients with relapsed or refractory diffuse large cell B-Cell lymphoma (DLBCL).

Patients and Methods.

This is a prospective, multicenter, phase II, open-label study. Patients with relapsed or refractory DLBCL with a maximum of two prior treatment lines were eligible. The STORM regimen consisted of Rituximab 375 mg/m² (day 2) and DHAP (Dexamethasone 40mg day 3-6, Cisplatine 100 mg/m² day 3, Cytarabine 2x2 g/m² day 4)  with Temsirolimus added on day 1 and 8 of a 21 d cycle, with 2-4 cycles planned. In part I, dose levels for the mTOR inhibitor Temsirolimus from  25, 50, 75 and 100 mg were predefined.

Results.

Here we report on the preliminary results of part I of this clinical trial. 15 patients were included  -  8 patients in the 25 mg cohort and 7 patients in the 50 mg cohort. Median age was 70 (range 49-76) years and median number of prior regimen was 1. Two DLTs (one venous thrombosis in the 25 mg cohort, one esophagus infection in the 50 mg cohort) were observed. The most frequent non-hematologic side effects were nausea (9 pts, 60%), epistaxis (7 pts, 47%), fatigue (6 pts, 40%), increased ALT (6 pts, 40%) and increased creatinine (6 pts, 40%). Frequent grade 3/4 events (n>2) in both cohorts (25mg|50mg) included leukopenia (11 pts, 73% - with a mean duration of 4.4 days | 6.7 days ), thrombocytopenia (11 pts, 73% - with a mean duration of 4.6 days | 11.9 days), lymphopenia (6pts, 40%), anemia (5 pts, 33%), neutropenia (3 pts, 20%), renal failure (3 pts, 20%) and infections (4 pts, 27%, bladder infection, esophagus infection, central venous access infection, soft tissue infection, mucositis). Based on the observed toxicity profile, the independent data safety committee recommended a Temsirolimus dose of 25 mg given on day 1 and 8 for the part II extension cohort of the trial.  All but one evaluable patient responded (10/11 pts, 91%), with two CRs and one CRu (27%). Four patients could not be evaluated for response at the time of this report. After a median follow up of 12 (range 5-22) months, no relapse has been documented so far (1 pt lost to follow up).

Conclusion.

Temsirolimus can be safely added to DHAP and Rituximab with promising activity. Recruitment into part II is ongoing and updated results will be presented.