A long-term response to allogeneic hemopoietic stem cell transplantation from haploidentical donor and post-transplant therapy in an adolescent with primary resistant neuroblastoma

Neuroblastoma (NB) is the most frequent pediatric extracranial solid tumor characterized by extreme biological heterogeneity with variable clinical course. Older age is an important risk factor. These patients may lack other common risk features but still have a chemoresistant disease with dismal prognosis. As there is currently no consensus on optimal treatment for patients with primary resistant NB, a number of clinical options is being explored including immunotherapy-based approaches. Immunotherapy with dinutuximab beta (DB) have proven its effectiveness as maintenance therapy. Allogeneic stem cell transplantation from haploidentical donor (haplo-HSCT) may be an effective consolidation in some cases. However, all forms of immunotherapy are much less effective in patients with large residual tumor. While there is no data on immune checkpoints inhibitors effectiveness in NB, some patients may benefit from this option as a part of complex immunotherapy strategy. Case presentation A 12-year old girl with gross paravertebral thoracic and abdominal tumor was diagnosed with undifferentiated neuroblastoma and bone metastases. While there was no response to several lines of chemotherapy, and only partial tumor resection was possible, the hematopoietic stem cell transplantation from haploidentical donor (haplo-HSCT) was performed as salvage therapy. Since there was only minor decrease in tumor volume with good dynamics by MIBG scan, additional post-transplant therapy was initiated. External beam radiotherapy was given for local control. The patient also received combined immunotherapy with DB and nivolumab. Currently, 3.5 years post haplo-HSCT, despite still gross residual tumor mass, it is MIBG-negative and shows signs of differentiation. Conclusion The combination of haplo-HSCT with post-transplant anti-GD2 and nivolumab may lead to a long-term response in an adolescent with primary resistant NB in spite of a large residual tumor mass.