ENGRAFTMENT AND MOLECULAR MONITORING OF CD34(-BLOOD STEM-CELL TRANSPLANTS FOR FOLLICULAR LYMPHOMA - A PILOT-STUDY() PERIPHERAL)

Purpose: A pilot study to validate the use of CD34(+) selection (Cepra te SC) of blood stem-cell collection in patients with advanced follicu lar lymphoma receiving myeloablative chemoradiotherapy, Patients and m ethods: Seventeen patients were entered onto the protocol. Thirteen of 17 patients have undergone transplantation; the median age is 42.5 ye ars (range, 33 to 51), seven of 13 are stage IVB, two stage IVA, three stage IIIB, and one stage IIB. All except two patients were treated a fter first or subsequent relapses after receiving cyclophosphamide, do xorubicin, vincristine, and prednisone (CHOP) chemotherapy to achieve a good partial (six of 13) or complete (seven of 13) response before s tem-cell mobilization with cyclophosphamide 3 g/m(2) and filgrastim 30 0 mu g once daily. Results: Eleven of 13 patients had a detectable t(1 4; 18) by nested polymerase chain reaction (PCR). Median CD34(+) count before selection was 2.9 x 10(6)/kg (range, 1.17 to 11.3) and after C D34(+) selection was 1.54 x 10(6)/kg (range, 0.88 to 7.6) with a media n CD34(+) yield of 62.4% (range, 17% to 95%) and purity of 60% (range, 39.3% to 73%). Of the 11 patients known to have t(14; 18), 10 had PCR -detectable contamination of stem-cell harvests that became PCR negati ve in six of the 10 after CD34(+) selection. Engraftment was rapid wit h a median day to absolute neutrophil count (ANC) greater than 0.5 x 1 0(9)/L of 13 days (range, 11 to 21) and platelet count greater than 20 x 10(9)/L of 14 days (range, 10 to 44). With a median follow-up durat ion of 15 months, three patients have remained persistently PCR-positi ve, two of whom received PCR-positive stem cells. Two have relapsed, O f the seven patients who received PCB-negative stem cells, five have h ad no PCR-detectable disease in posttransplant bone marrow samples, Co nclusion: Longer follow-up duration is required to determine the signi ficance of these findings, but we have confirmed the feasibility of CD 34(+) selected cells to deplete peripheral-blood stern cells of tumor cells from patients undergoing high-dose therapy for follicular lympho ma. (C) 1997 by American Society of Clinical Oncology.