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Tandem transplants provide EFS edge in pediatric neuroblastoma

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Post-ASCT therapy may influence results

The ANBL0532 trial also does not address the important question as to whether tandem high-dose chemotherapy with autologous stem cell transplant results in benefit for all-comers with high-risk neuroblastoma, because just over half of the eligible patients underwent randomization. Although characteristics of the entire cohort and the randomized cohort were similar with respect to age, stage, tumor histology, and MYCN status, there may be differences unrelated to widely accepted neuroblastoma risk variables. A separate but important challenge in interpretation of these results, as with any clinical trial results, is to understand the generalizability of findings to patient populations who may not be enrolling in trials. Previous work in pediatric oncology showed that trial enrollment correlated with race, age, and zip code, and it is difficult to know whether the results of the ANBL0532 trial are applicable to patient groups who may not be well represented.

An additional challenge is that even though a difference in event-free survival was detected between groups assigned to receive single versus tandem transplant, and a difference in overall survival was detected in a post hoc analysis of patients who received immunotherapy, no difference in overall survival was detected in the overall randomized cohort. Overall survival was evaluated as a secondary outcome but the trial was not powered to detect a difference in overall survival. Moreover, as noted by the authors, overall survival can be influenced by therapies delivered after relapse. This is particularly relevant in an era in which relapse therapies have been shown to induce responses, including periods of remission.

Remarks from Rochelle Bagatell, MD, from the University of Pennsylvania, Philadelphia, and Meredith S. Irwin, MD, from the Hospital for Sick Children in Toronto, are adapted and condensed from an editorial accompanying the study by Park et al. Dr. Bagatell is the vice chair of the Children’s Oncology Group Neuroblastoma Disease Committee. Dr. Irwin reported receiving personal fees from Bayer Canada outside the submitted work and is the vice chair of the Children’s Oncology Group Neuroblastoma Biology Committee. Neither Dr. Bagatell nor Dr. Irwin was involved in the design of the ANBL0532 trial or in the analysis of the results.



For young patients with high-risk neuroblastoma, an intensive consolidation regimen with tandem autologous stem cell transplants was associated with significantly better event-free survival, compared with single-transplant consolidation, results of a randomized trial show.

Among 355 patients with high-risk neuroblastoma, the 3-year event-free survival (EFS) rate was 61.6% for patients randomized to tandem (sequential) autologous stem cell transplants, compared with 48.4% for patients randomized to a single transplant (P = .006), reported Julie R. Park, MD from Seattle Children’s Hospital in Washington, and coinvestigators in the Children’s Oncology Group’s ANBL0532 trial.

“Results of the current study are consistent with earlier trials demonstrating that induction chemotherapy followed by consolidation with autologous transplant improved EFS, compared with less intensive consolidation, and that further intensification of consolidation benefits some patients,” they wrote in JAMA.

But of the 652 patients enrolled in the study, only 355 were actually randomized. Although the randomization rate was slightly higher than anticipated, the authors acknowledged that the results may not apply to all patients with high-risk neuroblastoma.

Patients eligible for the trial included those with International Neuroblastoma Staging System (INSS) stage 4 neuroblastoma aged older than 18 months; INSS stage 3 neuroblastoma aged older than 18 months with International Neuroblastoma Pathology Classification of unfavorable histology; INSS stage 2, 3, 4, or 4S neuroblastoma with MYCN amplification; and INSS stage 4 neuroblastoma diagnosed from age 12-18 months whose tumors showed any unfavorable features. Patients initially diagnosed with non–high-risk neuroblastoma (including stage 1) who had not received chemotherapy and whose disease had progressed to high-risk neuroblastoma were also eligible.

Following induction with two cycles of topotecan and cyclophosphamide, patients underwent peripheral blood stem cell collection, followed by four alternating cycles of cisplatin and etoposide and doxorubicin and cyclophosphamide, and vincristine.

For those patients who did not have primary tumors resected at diagnosis, resection was performed after the fourth or fifth cycle.

Those patients who after induction had no disease progression, no uncontrolled infection, sufficient stem cell levels, and adequate organ function were then eligible for randomization. One patient did not receive any therapy, 27 were nonrandomly assigned to single transplant, 62 were not eligible for randomization, and 207 were not randomized because of physician or family preference.

Of the remaining patients (median age at diagnosis, 36.1 months) 176 were randomized to receive tandem transplant with thiotepa and cyclophosphamide followed by dose-reduced carboplatin, etoposide, and melphalan conditioning, and 179 were randomized to single transplant with standard-dose carboplatin, etoposide, and melphalan.

A total of 17 patients died on study from toxicity; 7 during induction and 10 during consolidation. Significant transplant-related toxicities included mucositis in 11.7% of tandem-transplant patients and 15.4% of single-transplant patients, and infections in 17.8% versus 18.3%, respectively.

As noted before, 3-year EFS from the time of randomization, the primary endpoint, was higher for patients in the tandem-transplant arm (61.6% vs. 48.4%, P = .006).

The median duration of follow-up after randomization for patients without relapse, disease progression, second malignancy, or death was 5.6 years.

A post hoc analysis of the randomized patients showed a 3-year overall survival rate of 71.6%, which did not differ significantly between the study arms (74.1% for the tandem-transplant group vs. 68.1% for the single-transplant group). The analysis also showed that 3-year EFS and overall survival was higher in the tandem- versus single-transplant groups among 250 patients who also received immunotherapy with isotretinoin plus an anti-GD2 chimeric antibody and cytokines.

The trial was supported by grants from the National Institutes of Health, National Cancer Institute, National Clinical Trials Network Operations Center, and St. Baldrick’s Foundation. Dr. Park reported no relevant disclosures. Multiple coauthors disclosed grants or personal feeds outside the submitted work.

SOURCE: Park JR et al. JAMA. 2019;322(8):746-55.

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