No Difference in Outcome With Purged vs Nonpurged Peripheral Blood Stem Cell Transplantation in High-Risk Neuroblastoma
The contribution of purging of peripheral blood stem cells to outcome of autologous stem cell transplantation in high-risk neuroblastoma has not been defined. In a trial (COG A3973) reported in Lancet Oncology by Susan G. Kreissman, MD, of Duke University Medical Center, and colleagues, children and young adults aged less than 30 years with high-risk neuroblastoma received purged or nonpurged peripheral blood stem cell transplantation. Purging of peripheral blood stem cells was not associated with improved outcome compared with nonpurged peripheral blood stem cells.
Study Details
In this phase III trial, 486 patients were treated with six cycles of induction chemotherapy, myeloablative consolidation, and radiation therapy to the primary tumor site plus metastases present before myeloablative therapy, followed by oral isotretinoin. Peripheral blood stem cells were collected after two induction cycles. For purging, peripheral blood stem cells were mixed with carbonyl iron, and phagocytic cells were removed with samarium cobalt magnets. Remaining cells were mixed with immunomagnetic beads prepared with five monoclonal antibodies targeting neuroblastoma cell surface antigens, and attached cells were removed using magnets. Patients were randomly assigned to undergo autologous stem cell transplantation with purged peripheral blood stem cells (n = 243) or nonpurged peripheral blood stem cells (n = 243) after six cycles of induction therapy. The primary endpoint was event-free survival on intention-to-treat analysis.
Outcomes
Of 243 patients in each group, peripheral blood stem cells were collected from 229 patients (94%) in the purged group and 236 patients (97%) in the nonpurged group, and 180 (74%) and 192 (79%), respectively, received transplants. Five-year event-free survival was 40% in the purged group vs 36% in the nonpurged group (P = .77). Five-year overall survival was 50% in the purged group and 51% in the nonpurged group (P = .81).
Toxic deaths occurred in 8 patients in the purged group and 7 in the nonpurged group during induction and in 8 and 4, respectively, during consolidation. The most common adverse event was grade 3 or worse stomatitis during both induction (36% of patients in the purged group and 38% of patients in the nonpurged group) and consolidation (74% and 76%). Serious adverse events during induction were grade 3 or higher decreased cardiac function (4 and 5 patients) and elevated creatinine (5 and 6 patients) and serious adverse events during consolidation were sinusoidal obstructive syndrome (7% and 9%), acute vascular leak (6% and 5%), and decreased cardiac function (1 and 4 patients).
The investigators concluded, “Immunomagnetic purging of [peripheral blood stem cells] for autologous stem cell transplantation did not improve outcome, perhaps because of incomplete purging or residual tumor in patients. Nonpurged [peripheral blood stem cells] are acceptable for support of myeloablative therapy of high-risk neuroblastoma.”
The study was supported by the National Cancer Institute and Alex’s Lemonade Stand Foundation.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
