High-Dose Bi-Weekly THP-COP Induction Treatment Followed by High-Dose Therapy with Autologous Peripheral Blood Stem Cell Transplantation for Advanced-Stage Follicular Lymphoma as First-Line Therapy.

Introduction: Most patients with advanced-stage follicular lymphoma(FL) cannot be cured by conventional chemotherapy and have median survival of 7 to 10 years. High-dose chemotherapy (HDT) supported by autologous stem cell transplantation(ASCT) gives a survival benefit for patients with aggressive lymphoma. Recent several multicenter studies have shown that clinical and molecular remissions can be attained in patients with FL receiving intensified high-dose sequential chemotherapy and autografting. We have reported the efficacy and safety of high-dose bi-weekly THP-COP with G-CSF support (HDBW-TCOPG) for non-Hodgkin’s lymphoma. Therefore, we performed a pilot clinical trial to evaluate the efficacy and toxicity of HDBW-TCOPG followed by HDT with ASCT as first-line therapy in patients with advanced-stage FL.

Patients and methods: Between August 1998 and December 2003, 10 Japanese patients with previously untreated FL from whom informed consent was obtained were included in this single-center pilot study. Median age was 48 years. All patients had stage 3 or 4 disease, aaIPI LI 8 and HI 2. Histological subtypes of FL included grade 1 4; grade 2 4; grade 3a 2. HDBW-TCOPG consisted of pirarubicin 70 mg/m² on day 1; cyclophosphamide 1000 mg/m² on day 1; vincristine 1.4 mg/m² on day 1; predonisolone 50 mg/m² from day 1 to 5; lenograstim 2.0 mg/kg/day from day 3. Five patients who enrolled after rituximab was approved for indolent B-cell lymphoma in Japan received induction therapy combined HDBW-TCOPG with rituximab 375mg/m² on day -2 (R-HDBW-TCOPG). Six cycles were administered at intervals of two weeks. PBSC were collected during the later cycles of HDBW-TCOPG or on the recovery of high-dose etoposide regimen (500mg/m² for 3 days) administered after the completion of HDBW-TCOPG. Leukaphereses were performed until a minimum of 2.0x10⁶/kg CD34+ cells had been collected. The conditioning regimen consisted of ranimustine 200mg/m² on day-7 and -2; paraplatin 300mg/m² on day -6, -5, -4, -3; etoposide 500mg/m² on day −5, −4, −3; cytarabine 2.5 g/m² every 12 hours on day −2, −1 (MCE-CA regimen) in 2 patients or cyclophosphamide 50mg/kg on day −2, −1 (MCEC regimen) in 8 patients.

Results: Sufficient numbers of PBSC were collected in 5 of 7 patients mobilized with HDBW-TCOPG and in all 5 patients with high-dose etoposide. The median time to reach total number of leukocytes of 1.0 x10⁹/l was nine days (range 8–11). All 10 patients who were in PR at the end of HDBW-TCOP(G) achieved CR post APBSCT. After a median follow up of 36.6 months (range 7–66 months) PFS and OS are 90% and 90%, respectively, for all patients. One patient developed secondary myeloid leukemia with t(3;21) and died at 35 months after APBSCT without signs of recurrence of lymphoma. Another patient who relapsed at 35 months after transplantation. IgH or BCL2 rearrangement was detected by PCR analysis prior to therapy in three patients and one of them still showed detectable disease after HDBW-TCOPG induction. However, all three patients demonstrated MRD negativity after HDT with ASCT.

Conclusion: HDBW-TCOPG as induction therapy followed by HDT with ASCT is feasible for advanced-stage FL with acceptable toxicity, and this short term highly intensified therapy may induce cure of the disease by minimizing MRD, but longer follow up is needed to evaluate the impact on survival.