Résumé
Temsirolimus has shown clinical activity in heavily pretreated patients with mantle cell lymphoma (MCL) leading to evaluate tolerability and efficacy of combinations regimens. The T3 trial is a multicenter, Phase IB, dose escalation study (3+3) of Temsirolimus administered in combination with three chemotherapy regimens in relapse or refractory (R/R) mantle cell lymphoma (MCL) patients. The primary objective was to determine the maximum tolerated dose (MTD). DLT was assessed during the first two cycles.
Study design: Temsirolimus was added for 6 cycles to R-CHOP (R-CHOP-T) administered every 3 weeks or to or R-FC (R-FC-T) and R plus high dose cytarabine and dexamethasone (R-DHA-T) administered every 4 weeks. Temsirolimus was administered IV at day 2, 8 and 15. Three dose levels of Temsirolimus was tested: 15 mg, 25 mg (starting dose) and 50 mg. Patients were treated with one of these 3 chemotherapy regimens according to the choice of local investigator and no randomization was performed. LYSARC was the sponsor and the trial was conducted with a financial support of Pfizer Results: forty-one patients (R-CHOP-T n=10; R-FC-T n=14 and R-DHA-T, n=17)were enrolled. At time of inclusion, median age of patients was 68y (56-79), 32 patients were male, median time from last therapy to inclusion was 23,1m (2-143), MIPI score was low in 8, intermediate in 13 and high in 19 cases (missing=1). Previous lines of treatment included autologous stem cell transplantation in 18 patients. Among patients treated in the R-CHOP-T arm, all patients (n=4) presented grade 3 toxicities at the 25mg dose level. At the 15mg dose level (n=6), one DLT occurs (Thrombopenia). Consequently, the maximum tolerated dose (MTD) of Temsirolimus in the R-CHOP-T was 15 mg. Among patients of the R-FC-T arm (n=14) and R-DHA-T, the recommended dose of Temsirolimus has not been found because of toxicities that occurred at all Temsirolimus doses (25 and 15mg). Hematologic grade 3/4 toxicities were the most frequent, mainly thrombocytopenia (n=28). In term of efficacy, ORR (CR/CRu/PR) during treatment period was 40% for R-CHOP-T including 2 patients who reached CR, 35,7% for R-FC-T including 3 patients who reached CR and 47,1% for R-DHA-T including 6 patients who reached CR. For all patients, mFU is 30.5 m (23-39). The mPFS and mOS according to treatment arms and for all patients (n=41) are as followed: 15,1m and not reached for R-CHOP-T (n= 10); 8.6m and 17.8 m for R-FC-T (n=14) ; 11.9m and 24.2m for R-DHA-T (n=17).
In conclusion, the recommended dose of Temsirolimus for R-CHOP-T is 15mg D1,8,15. We are not able to recommend a dose of Temisrolimus for both R-DHA-T and R-FC-T. Hematologic toxicity was the main concern in all arms. A good efficacy in term of response rates PFS and OS was observed in all arms suggesting that Temsirolimus-based chemotherapy regimen should be further investigated in prospective trials but dose of Temsirolimus should be carefully investigated.