Iodine-131-metaiodobenzylguanidine therapy with reduced-intensity allogeneic stem cell transplantation in recurrent neuroblastoma

Phase I/II clinical trial of high-dose [131I] meta-iodobenzylguanidine therapy for high-risk neuroblastoma preceding single myeloablative chemotherapy and haematopoietic stem cell transplantation

PURPOSE

Paediatric high-risk neuroblastoma has poor prognosis despite modern multimodality therapy. This phase I/II study aimed to determine the safety, dose-limiting toxicity (DLT), and efficacy of high-dose ¹³¹I-meta-iodobenzylguanidine (¹³¹I-mIBG) therapy combined with single high-dose chemotherapy (HDC) and haematopoietic stem cell transplantation (HSCT) in high-risk neuroblastoma in Japan.

METHODS

Patients received 666 MBq/kg of ¹³¹I-mIBG and single HDC and HSCT from autologous or allogeneic stem cell sources. The primary endpoint was DLT defined as adverse events associated with ¹³¹I-mIBG treatment posing a significant obstacle to subsequent HDC. The secondary endpoints were adverse events/reactions, haematopoietic stem cell engraftment and responses according to the Response Evaluation Criteria in Solid Tumours version 1.1 (RECIST 1.1) and ¹²³I-mIBG scintigraphy. Response was evaluated after engraftment.

RESULTS

We enrolled eight patients with high-risk neuroblastoma (six females; six newly diagnosed and two relapsed high-risk neuroblastoma; median age, 4 years; range, 1-10 years). Although all patients had adverse events/reactions after high-dose ¹³¹I-mIBG therapy, we found no DLT. Adverse events and reactions were observed in 100% and 25% patients during single HDC and 100% and 12.5% patients during HSCT, respectively. No Grade 4 complications except myelosuppression occurred during single HDC and HSCT. The response rate according to RECIST 1.1 was observed in 87.5% (7/8) in stable disease and 12.5% (1/8) were not evaluated. Scintigraphic response occurred in 62.5% (5/8) and 37.5% (3/8) patients in complete response and stable disease, respectively.

CONCLUSION

¹³¹I-mIBG therapy with 666 MBq/kg followed by single HDC and autologous or allogeneic SCT is safe and efficacious in patients with high-risk neuroblastoma and has no DLT.

TRIAL REGISTRATION NUMBER

jRCTs041180030.

NAME OF REGISTRY

Feasibility of high-dose iodine-131-meta-iodobenzylguanidine therapy for high-risk neuroblastoma preceding myeloablative chemotherapy and haematopoietic stem cell transplantation (High-dose iodine-131-meta-iodobenzylguanidine therapy for high-risk neuroblastoma). URL OF REGISTRY: https://jrct.niph.go.jp/en-latest-detail/jRCTs041180030 .

DATE OF ENROLMENT OF THE FIRST PARTICIPANT TO THE TRIAL

12/01/2018.

Iodine-131 metaiodobenzylguanidine therapy for neuroblastoma: reports so far and future perspective

Neuroblastoma, which derives from neural crest, is the most common extracranial solid cancer in childhood. The tumors express the norepinephrine (NE) transporters on their cell membrane and take in metaiodobenzylguanidine (MIBG) via a NE transporter. Since iodine-131 (I-131) MIBG therapy was firstly reported, many trails of MIBG therapy in patients with neuroblastoma were performed. Though monotherapy with a low dose of I-131 MIBG could achieve high-probability pain reduction, the objective response was poor. In contrast, more than 12 mCi/kg I-131 MIBG administrations with or without hematopoietic cell transplantation (HCT) obtain relatively good responses in patients with refractory or relapsed neuroblastoma. The combination therapy with I-131 MIBG and other modalities such as nonmyeloablative chemotherapy and myeloablative chemotherapy with HCT improved the therapeutic response in patients with refractory or relapsed neuroblastoma. In addition, I-131 MIBG therapy incorporated in the induction therapy was proved to be feasible in patients with newly diagnosed neuroblastoma. To expand more the use of MIBG therapy for neuroblastoma, further studies will be needed especially in the use at an earlier stage from diagnosis, in the use with other radionuclide formations of MIBG, and in combined use with other therapeutic agents.

I-131-Metaiodobenzylguanidine therapy with allogeneic cord blood stem cell transplantation for recurrent neuroblastoma

Iodine-131-metaiodiobenzylguanidine (131I-MIBG) therapy combined with allogeneic cord blood stem cell transplantation (SCT) was used to treat a 4-year-old girl with recurrent neuroblastoma. The patient experienced relapse 2 years after receiving first-line therapies, which included chemotherapy, surgical resection, irradiation, and autologous peripheral SCT. Although 131I-MIBG treatment did not achieve complete remission, the size of the tumor was reduced after treatment. Based on our findings, we suggest that 131I-MIBG treatment with myeloablative allogeneic SCT should be considered as first-line therapy for high-risk neuroblastoma patients when possible.

Treatment of high-risk neuroblastoma

Although high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT) have improved the prognosis for patients with high-risk neuroblastoma (NB), event-free survival rates remain in the range of 30 to 40%, which is unsatisfactory. To further improve outcomes, several clinical trials, including tandem HDCT/autoSCT, high-dose ¹³¹I-metaiodobenzylguanidine treatment, and immunotherapy with NB specific antibody, have been undertaken and pilot studies have reported encouraging results. Nonetheless, about half of high-risk NB patients still experience treatment failure and have no realistic chance for cure with conventional treatment options alone after relapse. Therefore, a new modality of treatment is warranted for these patients. In recent years, several groups of investigators have examined the feasibility and effectiveness of reduced-intensity allogeneic stem cell transplantation (RI alloSCT) for the treatment of relapsed/progressed NB. Although a graft-versus-tumor effect has not yet been convincingly demonstrated in the setting of relapsed NB, the strategy of employing RI alloSCT has provided hope that treatment-related mortality will be reduced and a therapeutic benefit will emerge. However, alloSCT for NB is still investigational and there remain many issues to be elucidated in many areas. At present, alloSCT is reserved for specific clinical trials testing the immunomodulatory effect against NB.

Reduced-intensity allogeneic stem cell transplantation for children with neuroblastoma who failed tandem autologous stem cell transplantation

BACKGROUND

To date, no effective curative option is available for children with neuroblastoma (NB) who failed tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT). The present study evaluated the feasibility and efficacy of reduced-intensity allogeneic stem cell transplantation (RI alloSCT) in six children with NB who failed tandem HDCT/autoSCT.

PROCEDURE

A cyclophosphamide/fludarabine regimen was used as a conditioning for HLA-matched SCT, and ATG was added for haploidentical SCT. Peripheral blood stem cells from four HLA-matched donors and two haploidentical donors were transplanted. Immune suppression was rapidly tapered if graft-versus-host disease (GVHD) was absent.

RESULTS

Regimen-related short-term toxicity was manageable, and complete donor chimerism was achieved in the early period after transplant. Grade I/II acute GVHD developed or was induced in all patients. Tumor response, attributed to a graft-versus-tumor (GVT) effect, was observed in two of six patients after induction of acute GVHD. The other four patients with significant tumor burden prior to transplant had tumor progression despite presence of GVHD. However, it was difficult to effectively reduce the tumor burden prior to transplant through the use of conventional treatment modalities.

CONCLUSION

Although regimen-related short-term toxicity was manageable in intensively pretreated patients with NB, GVT effect was not sufficiently strong to control tumor progression in patients who had a significant tumor burden at transplant. Therefore, new treatment modalities to effectively reduce tumor burden prior to transplant in concert with post-transplant adjuvant treatment to enhance the GVT effect are needed to improve the outcome after RI alloSCT.

[Reduced intensity allogenic hematopoietic stem cell transplantation in children]

Better understanding of the antitumor effect of allogeneic transplant and the need to reduce the toxicity of the procedure, particularly in elderly patients have spurred the development of reduced-intensity conditioning regimens (RIC). These regimens allow fast engraftment with very low chemotherapy-induced toxicity. They are widely used in adults and there are numerous studies to demonstrate their feasibility and efficiency, but in pediatrics, the place of RIC remains to be determined. They can be proposed in two pediatric populations. First, solid tumors or hematological malignancies remaining unresponsive to the reference strategies according to best practices in pediatrics. Second, in children presenting malignancies for which allografting is the only recognized curative indication but is contraindicated with myeloablative conditioning regimens. More than 100 pediatrics cases have been reported in various pathologies, including blood diseases, acute leukemia, Hodgkin's lymphoma and solid tumors, and promising results published recently underline how RIC warrants further investigation in prospective comparative multicentric trials. The use of new post-graft treatment modalities is expected to pave the way to the development of RIC in pediatric patients.

Treatment and outcomes of patients with relapsed, high-risk neuroblastoma: results of German trials

BACKGROUND

The prognosis of high-risk neuroblastoma patients has improved over the last decades. However, many patients experience relapse after successful initial treatment. We retrospectively analyzed the long-term outcome of relapsed patients of three consecutive national neuroblastoma trials.

METHODS

Patients were included when they fulfilled all of the following criteria: Age at diagnosis being 1 year or older, first diagnosis between 1990 and 2007, stage 4 disease or stage 3 neuroblastoma with MYCN amplification, and relapse or progression after successful first-line autologous stem cell transplantation (ASCT).

RESULTS

A total of 451 high-risk neuroblastoma patients 1 year or older underwent ASCT during first-line treatment, 253 experienced recurrence of disease, 158 received salvage chemotherapy, and 23 of them finally underwent a second ASCT. These 23 patients had a better median survival (2.08 years) and 3-year survival rate from recurrence (43.5 ± 10.9%) compared to 74 patients who had no second chemotherapy (median survival 0.24 years, 3-year survival rate 4.0 ± 2.6%) and 135 patients who underwent second-line chemotherapy but did not undergo second ASCT (median survival of 0.89 years, 3-year survival rate 9.6 ± 2.8%, P < 0.001). By February 2010, 3/23 patients were in complete remission, 3/23 in very good partial remission, 1/23 in partial remission, 14/23 patients died of disease after successful second ASCT, and 2/23 died of complications due to second ASCT.

CONCLUSION

Intensive second-line therapy is feasible. A small subgroup of relapsed high-risk neuroblastoma patients may benefit from intensive relapse chemotherapy and second ASCT. The potential of long-term survival justifies clinical trials on intensive second-line treatment.