High-dose melphalan with 6-hydroxydopamine-purged autologous bone marrow transplantation for poor-risk neuroblastoma

Naxitamab Combined with Granulocyte-Macrophage Colony-Stimulating Factor as Consolidation for High-Risk Neuroblastoma Patients in First Complete Remission under Compassionate Use-Updated Outcome Report

Naxitamab is an anti-GD2 antibody approved for the treatment of relapsed/refractory HR-NB. We report the survival, safety, and relapse pattern of a unique set of HR-NB patients consolidated with naxitamab after having achieved first CR. Eighty-two patients were treated with 5 cycles of GM-CSF for 5 days at 250 μg/m²/day (-4 to 0), followed by GM-CSF for 5 days at 500 μg/m²/day (1-5) and naxitamab at 3 mg/kg/day (1, 3, 5), on an outpatient basis. All patients but one were older than 18 months at diagnosis and had stage M; 21 (25.6%) pts had MYCN-amplified (A) NB; and 12 (14.6%) detectable MRD in the BM. Eleven (13.4%) pts had received high-dose chemotherapy and ASCT and 26 (31.7%) radiotherapy before immunotherapy. With a median follow-up of 37.4 months, 31 (37.8%) pts have relapsed. The pattern of relapse was predominantly (77.4%) an isolated organ. Five-year EFS and OS were 57.9% (71.4% for MYCN A) 95% CI = (47.2, 70.9%); and 78.6% (81% for MYCN A) 95% CI = (68.7%, 89.8%), respectively. EFS showed significant differences for patients having received ASCT (p = 0.037) and pre-immunotherapy MRD (p = 0.0011). Cox models showed only MRD as a predictor of EFS. In conclusion, consolidation with naxitamab resulted in reassuring survival rates for HR-NB patients after end-induction CR.

Autologous Stem-Cell Transplantation for High-Risk Neuroblastoma: Historical and Critical Review

Simple Summary

The original idea that providing higher doses of cytotoxic agents will result in higher rates of tumor cell killing was proposed in the 1980s. Preclinical data supported clinical testing. Advancements in bone marrow and peripheral stem-cell support technologies during the 1980s and 1990s allowed for clinical developments that permitted testing the higher dose hypothesis in oncology patients. The results of almost 20 years of clinical trials proved the linear relationship between dosing and clinical outcome to be mostly inaccurate. As a consequence, the adult oncology field abandoned high-dose chemotherapy strategies by the turn of the 21st century. Neuroblastoma is the only pediatric extracranial solid tumor where high-dose chemotherapy has remained part of the standard management for high-risk cases. This systematic review aims to understand the historical reason for such an exception and analyzes data challenging the benefit of high-dose chemotherapy and autologous stem-cell transplants in the era of anti-GD2 immunotherapy.

Abstract

Curing high-risk neuroblastoma (HR-NB) is a challenging endeavor, which involves the optimal application of several therapeutic modalities. Treatment intensity for cancer became highly appealing in the 1990s. Investigative trials assumed that tumor response correlated with the dosage or intensity of drug(s) administered, and that this response would translate into improved survival. It was postulated that, if myelotoxicity could be reversed by stem-cell rescue, cure might be possible by increasing the dose intensity of treatment. The principle supported autologous stem-cell transplant (ASCT) strategies. High-dose therapy transformed clinical practice, legislation, and public health policy, and it drove a two-decade period of entrepreneurial oncology. However, today, no ASCT strategies remain for any solid tumor indication in adults. As with most solid malignancies, higher dosing of cytotoxic agents has not resulted in a clear benefit in survival for HR-NB patients, whereas the long-term toxicity has been well defined. Fortunately, novel approaches such as anti-GD2 immunotherapy have demonstrated a significant survival benefit with a much less adverse impact on the patient’s wellbeing. On the basis of extensive experience, persisting with administering myeloablative chemotherapy as the standard to treat children with HR-NB is not consistent with the overall aim in pediatric oncology of curing with as little toxicity as possible.

Lack of survival advantage with autologous stem-cell transplantation in high-risk neuroblastoma consolidated by anti-GD2 immunotherapy and isotretinoin

Since 2003, high-risk neuroblastoma (HR-NB) patients at our center received anti-G_D2 antibody 3F8/GM-CSF + isotretinoin – but not myeloablative therapy with autologous stem-cell transplantation (ASCT). Post-ASCT patients referred from elsewhere also received 3F8/GM-CSF + isotretinoin. We therefore accrued a study population of two groups treated during the same period and whose consolidative therapy, aside from ASCT, was identical. We analyzed patients enrolled in 1st complete/very good partial remission (CR/VGPR). Their event-free survival (EFS) and overall survival (OS) were calculated from study entry. Large study size allowed robust statistical analyses of key prognosticators including MYCN amplification, minimal residual disease (MRD), FCGR2A polymorphisms, and killer immunoglobulin-like receptor genotypes of natural killer cells. The 170 study patients included 60 enrolled following ASCT and 110 following conventional chemotherapy. The two cohorts had similar clinical and biological features. Five-year rates for ASCT and non-ASCT patients were, respectively: EFS 65% vs. 51% (p = .128), and OS 76% vs. 75% (p = .975). In multivariate analysis, ASCT was not prognostic and only MRD-negativity after two cycles of 3F8/GM-CSF correlated with significantly improved EFS and OS. Although a trend towards better EFS is seen with ASCT, OS is near identical. Cure rates may be similar, as close surveillance detects localized relapse and effective salvage treatments are applied. ASCT may not be needed to improve outcome when anti-G_D2 immunotherapy is used for consolidation after dose-intensive conventional chemotherapy.

CD34+ immunoselection of autologous grafts for the treatment of high-risk neuroblastoma

BACKGROUND

Graft contamination has been blamed for causing relapse in children with high-risk neuroblastoma (HRNB) after autologous hematopoietic stem cell transplantation (HSCT).

PROCEDURE

We report the long-term results of hematopoietic reconstitution, post-transplant complications, and clinical outcome of 44 children with HRNB treated with busulfan/melphalan high-dose chemotherapy followed by transplantation of purged CD34+ immunoselected autologous peripheral HSCT. Minimal residual disease (MRD) of grafts was evaluated by anti-GD2 immunofluorescence or tyrosine hydroxylase reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Contaminating neuroblasts were found in 19/38 grafts (50%) before CD34+ positive selection, and none after (technique sensitivity of one cell in 10(5)). A median of 6.5 × 10(6) CD34+ cells/kg (range 0.8-23.7) were transplanted with only 2% of TRM. Neutrophils and platelet recovery occurred within a median of 12 days (range 9-47) and 44 days (range 12-259), respectively, without any secondary graft failure. Twenty-three percents of patients experienced a sepsis (10/44) and 14% a pyelonephritis (6/44). Recurrence of varicella zoster virus occurred in 21% of patients (9/44). Negative RT-PCR MRD within the leukapheresis product and cis-retinoic acid therapy were significantly and independently associated to a better survival (P < 0.05). Overall and event-free survivals at 5 years post-transplant were at 59.3% and 48.3% respectively.

CONCLUSIONS

Besides high rates of manageable infections due to late immune recovery, transplantation with CD34+ immunoselected grafts in HRNB children was feasible and did not affect long-term hematopoiesis.

Outcomes of the POG 9340/9341/9342 trials for children with high-risk neuroblastoma: a report from the Children's Oncology Group

BACKGROUND

From 1993 to 1995, the Pediatric Oncology Group (POG) enrolled patients with high-risk neuroblastoma on three sequential, conjoined studies: a phase II induction window (9340), followed by intensive multiagent induction chemotherapy (9341), and subsequent myeloablative therapy with autologous stem cell rescue (9342). We report here the outcomes of patients treated on these studies.

PATIENTS AND METHODS

Patients were between 1 and 21 years old with high-risk neuroblastoma. Phase II window therapy consisted of two courses of either paclitaxel, topotecan, or cyclophosphamide with topotecan. Induction therapy consisted of at least five cycles of intensive chemotherapy, followed by myeloablative therapy with purged autologous stem cell reinfusion. Patient responses, treatment toxicities, and overall and event-free survival rates were calculated.

RESULTS

Eighty-four percent of patients responded to induction chemotherapy, with 39% achieving complete response. Toxicities were primarily hematologic. The 7-year EFS and OS rates for all eligible patients on POG 9341 were 23 +/- 4% and 28 +/- 4%, respectively. The 7-year EFS and OS rates for patients treated on POG 9342 were 27 +/- 6% and 29 +/- 6%, respectively.

CONCLUSIONS

These studies were the first attempt by POG to use autologous stem cell transplantation for neuroblastoma treatment in a cooperative group setting. Toxicities and outcomes were comparable to contemporary cooperative group studies. The phase II induction window had no detectable effect on outcomes. New strategies are needed to improve survival for this devastating disease.

6-fluorodopamine selectively destroys neuroblastoma cells expressing the noradrenaline transporter

BACKGROUND

6-Hydroxydopamine (6-OHDA) was used for ex vivo purging of bone marrow from neuroblastoma cells before autologous transplantation. However, this concept failed because of the rapid autoxidation of 6-OHDA, which leads to the generation of cytotoxic reactive oxygen species (ROS), mainly in the incubation medium before 6-OHDA can be incorporated by neuroblastoma cells.

PROCEDURE

We based our experiments on the theory that, in contrast, 6-fluorodopamine (6-FDA), which is slowly converted to 6-OHDA at neutral pH, is able to enter neuroblastoma cells via the noradrenaline transporter (NA-T). Therefore, most ROS are generated inside the target cells.

RESULTS

Small amounts of ascorbate prevent the extracellular conversion of 6-FDA to 6-OHDA without affecting its cytotoxicity, leading to an even more selective effect of 6-FDA.

CONCLUSIONS

We conclude that 6-FDA is a promising substance for selective destruction of NA-T-positive neuroblastoma cells.

Neuroblastoma cells expressing the noradrenaline transporter are destroyed more selectively by 6-fluorodopamine than by 6-hydroxydopamine

6-Hydroxydopamine (6-OHDA) has been used for lesioning catecholaminergic neurons and attempted purging of neuroblastoma cells from hematopoietic stem cells in autologous bone marrow transplantation (ABMT). Neurotoxicity is mediated primarily by reactive oxygen species. In ABMT, 6-OHDA, as a purging agent, has been unsuccessful. At physiological pH it autooxidizes before targeted uptake, resulting in nonspecific cytotoxicity of nontarget cells. A catecholamine analogue, similar to 6-OHDA but with a lower rate of autooxidation enabling uptake by target cells, is thus required. Electron paramagnetic resonance spectra in this study show that 6-fluorodopamine (6-FDA) hydrolyzes slowly to 6-OHDA at physiological pH. Oxygen consumption, H(2)O(2), and quinone production are found to be intermediate between those of 6-OHDA and dopamine (DA). Relative neurotoxicity of these compounds was assessed by cell viability and DNA damage in the human neuroblastoma lines SH-SY5Y and SK-N-LO, which express and lack the noradrenaline transporter, respectively. Specific uptake of DA and 6-FDA by SH-SY5Y cells was demonstrated by competitive m-[(131)I]iodobenzylguanidine uptake inhibition. The competition by 6-OHDA was low owing to rapid autooxidation during incubation with equal toxicity toward both cell types. 6-FDA toxicity was preferential for SH-SY5Y cells and reduced in the presence of desipramine, a catecholamine uptake inhibitor. We demonstrate that 6-FDA cytotoxicity is more specific for cells expressing catecholamine reuptake systems than is 6-OHDA cytotoxicity.

High-dose therapy with stem cell rescue for pediatric solid tumors: rationale and results

Metastatic and recurrent pediatric solid tumors usually respond to chemotherapy but are likely to recur. Because of steep dose-response relationships, HDT requiring hematopoietic rescue may improve outcome. This strategy has recently been shown to be effective for metastatic neuroblastoma. Metastatic Ewing's sarcoma appears to be a closely analogous situation, and promising phase II studies suggest that a definitive trial of efficacy would be appropriate. Phase I or II trials remain appropriate and are needed to define further the efficacy of HDT for most other poor prognosis pediatric solid tumors.

Treatment of neuroblastoma stage 4 with 131I-meta-iodo-benzylguanidine, high-dose chemotherapy and immunotherapy. A pilot study

Disseminated neuroblastoma after infancy has a prognosis of approximately 10-20% with conventional therapy. We investigated the role of high-dose chemotherapy (HDCT) with peripheral blood stem cell (PBSC) rescue in combination with 131I-metaiodobenzylguanidine ([131I-m]IBG). 11 children with neuroblastoma stage 4 were pretreated within the German Neuroblastoma Trial NB90 and included in a high-dose concept for consolidation. Remission was documented by ultrasound, CT, NMR, or [123I-m]IBG scanning. HDCT was a combination of melphalan (180 mg/m2), carboplatin (1,500 mg/m2) and etoposide (40 mg/kg). All children were treated by [131I-m]IBG (0.58 GBq/kg) prior to high-dose treatment. All 11 children were additionally treated with antiGD2 murine- or chimeric-antibody (ch14.18). 4 children had no change to their remission status but three achieved a complete response (from a partial response to first line) and one a partial response (from no response to first line). The other 3 children progressed, 2 dying of their disease. Using Kaplan-Meier analysis, the probability of progression-free survival was 0.70 +/- 0.15 with a median observation time of 19 months. 9/11 children are alive, 8 without progression or relapse, whilst 2 have died of their disease. The combination of mIBG plus high-dose chemotherapy with PBSC support supplemented by immunotherapy with antiGD2 antibody appears to be a feasible and effective treatment regimen for disseminated neuroblastoma in this limited series. Larger numbers of patients should be treated to confirm these results.

Thiotepa and cyclophosphamide with stem cell rescue for consolidation therapy for children with high-risk neuroblastoma: a phase I/II study of the Pediatric Blood and Marrow Transplant Consortium

PURPOSE

We report the results of a phase I/II stem cell rescue trial for patients with high risk neuroblastoma.

PATIENTS AND METHODS

Fifty-one patients with a median age of 2.3 years (range 1 to 20) who were in their first complete remission (CR) (n = 8), very good partial remission (VGPR) (n = 23), partial remission (PR) (n = 5), or subsequent CR/PR (n = 7) after receiving a platinum-based induction regimen were consolidated with high dose chemotherapy and stem cell rescue. They received an ablative regimen of thiotepa (300 mg/m2/day for 3 days) and cyclophosphamide (1500 mg/m2/day for 4 days) followed by either purged marrow (n = 16), unpurged bone marrow (BM) (n = 23), or peripheral blood stem cell (PBSC) rescue (n = 13). The median nucleated cell doses administered were 2.7 x 10(8)/kg for unpurged marrow (range 1.1 to 13), 1.7 x 10(8)/kg for purged marrow (range 0.8 to 6.4), and 2.1 x 10(8)/kg for the PBSC (range 1.1 to 13).

RESULTS

Engraftment was achieved for all patients. The time to achieve an absolute neutrophil count (ANC) >500 x 10(9)/l was 19 days for patients who received purged BM (range 13 to 18), 17.5 days for patients who received unpurged BM (range 9 to 38), and 13 days for patients who received PBSC (range 9 to 25). An unsustained platelet count >20 x 10(9)/l was attained in 33.5 days by patients who received purged BM (range 13 to 100), 35 days for patients who received unpurged BM (range 14 to 128), and 20 days for patients who received PBSC (range 11 to 64). There was one infectious death in the unpurged marrow group caused by aspergillosis pneumonia, but none in the other two groups. Progressive disease (PD) developed in 21 patients at a median of 271 days (range 31 to 1230). The remaining 29 patients are progression-free at a median follow-up of 1190 days (range 530 to 2383).

CONCLUSION

We conclude that this regimen is well tolerated, and that progression-free survival (PFS) with this chemotherapy-only regimen compares favorably with regimens containing total body irradiation (TBI).

Autotransplants with peripheral blood stem cells and clinical results obtained in children: a review

Peripheral blood stem cell transplantation (PBSCT) is increasingly used to support cancer treatment in adults and children. In this review we describe methodological aspects of PBSCT, compare it with autologous bone marrow transplantation (autoBMT), and review the first clinical results obtained with PBSCT in childhood.