ASCO 2016: Tandem Autologous Stem-Cell Transplant Improves Outcomes for Children With High-Risk Neuroblastoma

Key Points

  • At 3 years, 61.4% of patients who received a double transplant were alive and cancer-free, compared to 48.4% of those who received a single transplant.
  • Among all patients on the study, the 3-year event-free survival from enrollment was 51% and 3-year overall survival was 68.3%.
  • Outcomes were generally better among patients who enrolled onto the immunotherapy trial that included anti-GD2 antibody plus cytokines after the transplant. Among those patients, the 3-year event-free survival rate was significantly higher for those who had been assigned to tandem transplant (73.2%) compared to those assigned to single transplant (55.5%). The 3-year overall survival rate was significantly higher with a tandem transplant than with a single transplant (85.6% vs 75.8%).

Historically, less than 50% of children with high-risk neuroblastoma live 5 or more years after diagnosis. A National Cancer Institute (NCI)-funded phase III trial performed by the Children’s Oncology Group found that adding a second autologous stem-cell transplant to standard therapy improves outcomes for these patients.

At 3 years, 61.4% of patients who received a double transplant were alive and cancer-free, compared to 48.4% of those who received a single transplant. Side effects were similar between single and double transplant.

These data were by presented Park et al in the Plenary Session of the 2016 ASCO Annual Meeting (Abstract LBA3).

“This finding will change the way we treat children with high-risk neuroblastoma in North America,” said lead study author Julie R. Park, MD, an attending physician at Seattle Children’s Hospital and Professor in Pediatrics at the University of Washington School of Medicine. “However, the regimen we use for high-risk neuroblastoma is also the most aggressive and toxic regimen we give to children with cancer. For that reason, future research needs to focus on both exploring possible late effects of current therapy and developing newer, less toxic therapies.”

About the Study

The trial enrolled children newly diagnosed with high-risk neuroblastoma, who were a median age of 3.1 years. The majority of patients (88%) had stage IV disease, and 38.2% had a tumor high-risk genetic abnormality called MYCN amplification.

All patients received six cycles of a multiagent induction chemotherapy regimen including an initial two cycles of high-dose cyclophosphamide/topotecan followed by collection of stem cells from the blood to be used for subsequent transplantation. At completion of the induction therapy, patients were randomly assigned to receive a single autologous stem-cell transplant with CEM (carboplatin/etoposide/melphalan) chemotherapy or a tandem autologous stem-cell transplant with thiotepa/cyclophosphamide prior to the first transplant followed by a modified CEM chemotherapy prior to second transplant. In the tandem autologous stem-cell transplant group, patients received the two transplants in the span of 6 to 8 weeks.

In the single autologous stem-cell transplant group, 129 out of 179 patients were subsequently enrolled onto a trial delivering anti-GD2 (dinutuximab [Unituxin]) plus cytokine immunotherapy after single-transplant consolidation therapy. A similar proportion of patients, 121 out of 176, received this immunotherapy following a tandem-transplant consolidation therapy.

The primary endpoint of the study was 3-year event-free survival. An “event” was defined as worsening or recurrence of cancer, diagnosis of a second cancer, or death from any cause.

Key Findings

Among all patients on the study, the 3-year event-free survival from enrollment was 51% and 3-year overall survival was 68.3%. Among patients randomized, the 3-year event-free survival rate from time of randomization was significantly higher following tandem transplant (61.4%) compared to single transplant (48.4%). The 3-year overall survival rate was slightly higher in the tandem-transplant group than the single-transplant group (74% vs 69.1%), but the difference was not statistically significant.

“We know that most neuroblastoma recurrences occur within 2 to 3 years from diagnosis, and that patients who had not had a recurrence at 3 years have a better chance of long-term survival. The study was not designed to observe a difference in overall survival, as this would take many years and cannot be adequately controlled for additional therapies received after an initial disease recurrence,” said Dr. Park. The researchers will continue following patients on this study for 10 years.

Outcomes were generally better among patients who enrolled onto the immunotherapy trial that included anti-GD2 antibody plus cytokines after the transplant. Among those patients, the 3-year event-free survival rate was significantly higher for those who had been assigned to tandem transplant (73.2%) compared to those assigned to single transplant (55.5%). The 3-year overall survival rate was significantly higher with a tandem transplant than with a single transplant (85.6% vs 75.8%).

The rates of severe toxicities were similar between treatment groups. Fewer treatment-related deaths occurred among patients who received a tandem transplant than among those who received a single transplant (2 vs 8).

The study received funding from the National Institutes of Health and was performed through the Children’s Oncology Group consortium.

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®.


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