Curable Potential with TBI Containing Regimen (L-PAM/TBI) Followed by In Vivo Purged Auto-PBSCT for Patients with Relapsed or Refractory Follicular Lymphoma.

Background: High-dose therapy (HDT) followed by autologous stem cell transplantation (ASCT) is one of the treatment options for relapsed or refractory follicular lymphoma (FL). However, whether ASCT is able to bring cure for relapsed FL, or what optimal high-dose regimen is remaining to be established.

Patients and Methods: Chemotherapy to obtain response and in vivo purging effect was CHASER regimen reported previously: rituximab 375 mg/m² on day 1; cyclophosphamide 1200mg/m² on day 3; cytarabine 2g/m² on days 4–5; etoposide 100mg/m² on days 3–5. Patients who achieved partial or complete response by CHASER were treated with L-PAM/TBI regimen comprised four fractionated TBI (8–12Gy) on days -6 to -5 or -5 to -4 and high-dose L-PAM 60 mg/m² on days -3 to -1 followed by autologous peripheral blood stem cell transplantation (auto-PBSCT) on day 0.

Results: Seventeen patients (median age 45 yrs; range, 26–59 yrs) were treated by this regimen. A median value of infused CD34 positive cells was 3.1×10⁶/kg (range, 1.7–10.1). All patients experienced grade 4 hematological toxicities and febrile neutropenia (FN) were observed in most of patients. Protracted thrombocytopenia was observed in some patients. No grade 4 non-hematologic toxicity was observed. Major grade 3 non-hematologic toxicities were FN and gastrointestinal. Two patients experienced grade 3 vomiting (11.8%), and nine patients experienced grade 3 diarrhea (52.9%), and two patients experienced grade 3 mucositis (11.8%). Two patients developed interstitial pneumonitis on days 130 and 229. They improved by steroid treatment immediately. The median times to reach a white blood cell count greater than 1.0×10⁹/L and platelet count 50×10⁹/L were 11days and 17days, respectively. Engraftment was obtained in all patients. There was no treatment related mortality within days 28 after auto-PBSCT. At a median follow-up of 2.6 years (range, 0.3–4.5 years), all patients were alive without relapse. No second malignancies was observed until now.

Conclusions: L-PAM/TBI regimen followed by in vivo-purged auto-PBSCT collected by CHASER might bring high %CR and have curable potential for patients with relapsed or refractory advanced FL, although large-scaled study is needed.