ABCB1/P-glycoprotein (Pgp) expression as stratification factor for treatment of patients with non-metastaticextremity high-grade osteosarcoma: A merged analysis of an Italian (ISG) and a Spanish (GEIS) sarcoma groups' multicentric prospective trials

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Background: Overexpression of ABCB1/P-glycoprotein (Pgp) predicts poor outcome in retrospective osteosarcoma series.Two prospective trials with Pgp expression and post-induction histologic response as stratification factors were activated in Italy (ISG/OS-2) and Spain (GEIS-33). Methods: Patients ≤ 40 years with extremity non-metastatic high-grade osteosarcoma were eligible. Analysisi of Pgp expression from diagnostic biopsy was centralized. Preoperatively, all patients received methotrexate, adriamycin, cisplatinum (MAP). Surgery was performed at week 8. All patients received a dose of adriamycin following surgery. In case of Pgp overexpression (Pgp+), mifamurtide (2 mg/m2 twice/week for 3 months then weekly for 6 months) was added after surgery, with 4 consecutive cycles of ifosfamide 3 gr/m2/day, day 1-5 (HDIFO) in case of poor histologic response (necrosis < 90%) to MAP. Patients without overexpression of Pgp (Pgp-) received MAP postoperatively, regardless the pathological response. From March 2013, an amendment increased high dose methotrexate cumulative dose from 60 g/m2 (5 cycles) to 120 mg/m2 (10 cycles). The post-amendment regimen was adopted in the observational prospective study by GEIS. Here we present the merged analysis of ISG/OS-2 patients treated post-amendment and GEIS-33. Results: From March 2013 to April 2018, 274 patients were included. Median age was 14 years (range 4-38), male/female: 163/111; 90 were Pgp-, 164 were Pgp+, 20 not evaluable. With a median follow-up of 48 months (1.3-78.5 months), the 3-year EFS and OS were 71.9% (95%CI 66-76.9) and 88% (95%CI: 83.2-91.5) respectively, with no inferior survival for Pgp positive patients and improved survival for good responders (Table). Conclusions: In this prospective uncontrolled study with a risk-adapted strategy for non-metastatic osteosarcoma, survival is superior to that of all ISG/GEIS previous series. The 3-year EFS of 71.9% compares favorably with other reports. Pgp+ patients performed well in this study, in which mifamurtide and HDIFO were added after a poor response to MAP. Clinical trial information: NCT01459484; NCT04383288. [Table: see text]

LGG-55. OUTCOME OF BRAF V600E PEDIATRIC GLIOMAS TREATED WITH TARGETED BRAF INHIBITION

Children with pediatric gliomas harboring BRAF V600E mutation have a poor outcome with current chemoradiation strategies. Our aim was to study the role of targeted BRAF inhibition in these tumors. We collected clinical, imaging, molecular and outcome information from BRAF V600E glioma patients treated with BRAFi across 29 centers from multiple countries. Sixty-seven patients were treated with BRAFi (56 pediatric low grade gliomas, PLGG and 11 pediatric high grade gliomas, PHGG) for up to 5.6 years. Objective responses were observed in 80% of PLGGs compared to 28% with conventional chemotherapy (p<0.001). These responses were rapid (median, 4 months), and sustained in 86% of tumors up to 5 years while on therapy. PLGG which discontinued BRAFi, 76.5% (13/17) progressed rapidly after discontinuation (median 2.3 months). However, upon re-challenge with BRAFi therapy, 90% achieved an objective response. Poor prognostic factors to conventional therapies, such as concomitant homozygous deletion of CDKN2A, were not associated with a lack of response to BRAFi. In contrast, only 36% of PHGG responded to BRAFi with all but one tumor progressing within 18 months. In PLGG, responses translated to 3-year progression-free survival of 49.6% (95%CI, 35.3% to 69.5%) vs 29.8% (95% CI, 20% to 44.4%) for BRAFi vs chemotherapy respectively (p=0.02). The use of BRAFi results in robust and durable responses while on therapy in BRAF V600E PLGG. Prospective studies are required to determine long-term survival and functional outcomes with BRAFi therapy in childhood gliomas.

Outcomes of BRAF V600E Pediatric Gliomas Treated With Targeted BRAF Inhibition

PURPOSE

Children with pediatric gliomas harboring a BRAF V600E mutation have poor outcomes with current chemoradiotherapy strategies. Our aim was to study the role of targeted BRAF inhibition in these tumors.

PATIENTS AND METHODS

We collected clinical, imaging, molecular, and outcome information from patients with BRAF V600E-mutated glioma treated with BRAF inhibition across 29 centers from multiple countries.

RESULTS

Sixty-seven patients were treated with BRAF inhibition (pediatric low-grade gliomas [PLGGs], n = 56; pediatric high-grade gliomas [PHGGs], n = 11) for up to 5.6 years. Objective responses were observed in 80% of PLGGs, compared with 28% observed with conventional chemotherapy (P < .001). These responses were rapid (median, 4 months) and sustained in 86% of tumors up to 5 years while receiving therapy. After discontinuation of BRAF inhibition, 76.5% (13 of 17) of patients with PLGG experienced rapid progression (median, 2.3 months). However, upon rechallenge with BRAF inhibition, 90% achieved an objective response. Poor prognostic factors in conventional therapies, such as concomitant homozygous deletion of CDKN2A, were not associated with lack of response to BRAF inhibition. In contrast, only 36% of those with PHGG responded to BRAF inhibition, with all but one tumor progressing within 18 months. In PLGG, responses translated to 3-year progression-free survival of 49.6% (95% CI, 35.3% to 69.5%) versus 29.8% (95% CI, 20% to 44.4%) for BRAF inhibition versus chemotherapy, respectively (P = .02).

CONCLUSION

Use of BRAF inhibition results in robust and durable responses in BRAF V600E-mutated PLGG. Prospective studies are required to determine long-term survival and functional outcomes with BRAF inhibitor therapy in childhood gliomas.

Phase I study of regorafenib in combination with vincristine and irinotecan in pediatric patients with recurrent or refractory solid tumors

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Background: In pediatric patients with solid tumors, regorafenib demonstrated acceptable tolerability and preliminary anti-tumor activity. This phase 1 study evaluated regorafenib in combination with vincristine/irinotecan in pediatric patients with rhabdomyosarcoma (RMS) and other solid tumors. Methods: Patients with relapsed/refractory tumors received intravenous vincristine (1.5 mg/m2, Days 1 and 8) and irinotecan (50 mg/m2/day, Days 1–5) plus once-daily oral regorafenib (patients 6– < 24 months: 60 mg/m2 escalating to 65 mg/m2; patients 2– < 18 years: 72 mg/m2 escalating to 82 mg/m2) on either Days 1–14 (concomitant dosing) or Days 8–21 (sequential dosing) during each 21-day cycle. As per protocol, at least 50% of patients were required to have RMS. Results: At the time of the cut-off, of 21 treated patients (RMS, n = 12; Ewing sarcoma, n = 5; neuroblastoma, n = 3; Wilms tumor, n = 1), two had concomitant (72 mg/m2) and 19 had sequential (72 mg/m2, n = 6; 82 mg/m2, n = 13) dosing. Median age was 10 years (1.5–17.0). Patients received a median of 3 cycles (1–17); dose reductions of irinotecan occurred in 62% of patients. Grade 3 dose-limiting toxicities were reported in both patients receiving concomitant dosing (peripheral neuropathy and liver injury; pain, vomiting, febrile aplasia) and one patient each in the sequential groups (rash and elevated AST; thrombocytopenia). Concomitant dosing was discontinued. The maximum tolerated dose and recommended phase 2 dose (RP2D) of regorafenib in the sequential combination was 82 mg/m2. The most common grade ≥3 treatment-emergent adverse events were neutropenia (71%), thrombocytopenia (33%), leukopenia (29%), anemia (24%), and ALT increased (24%). The response rate was 38%, including 1 complete (RMS) and 7 partial responders (5 RMS, 2 Ewing sarcoma); 3 of whom had prior irinotecan. Six (4 with alveolar subtype) of 12 patients with RMS had a response. Nine patients (43%) had stable disease (maximum duration 17 cycles). After the cut-off, partial response was reported for two additional patients (1 RMS, 1 Ewing sarcoma). Conclusions: Regorafenib can be combined at its single agent RP2D of 82 mg/m2 with standard-dose vincristine/irinotecan (with appropriate dose modifications) in pediatric patients with refractory/relapsed solid tumors in a sequential dosing schedule. Clinical activity was observed in patients with sarcoma. Clinical trial information: NCT02085148.

Risk stratification of high-risk metastatic neuroblastoma: A report from the HR-NBL-1/SIOPEN study

BACKGROUND

Risk stratification is crucial to treatment decision-making in neuroblastoma. This study aimed to explore factors present at diagnosis affecting outcome in patients aged ≥18 months with metastatic neuroblastoma and to develop a simple risk score for prognostication.

PROCEDURE

Data were derived from the European high-risk neuroblastoma 1 (HR-NBL1)/International Society for Paediatric Oncology European Neuroblastoma (SIOPEN) trial with analysis restricted to patients aged ≥18 months with metastatic disease and treated prior to the introduction of immunotherapy. Primary endpoint was 5-year event-free survival (EFS). Prognostic factors assessed were sex, age, tumour MYCN amplification (MNA) status, serum lactate dehydrogenase (LDH)/ferritin, primary tumour and metastatic sites. Factors significant in univariate analysis were incorporated into a multi-variable model and an additive scoring system developed based on estimated log-cumulative hazard ratios.

RESULTS

The cohort included 1053 patients with median follow-up 5.5 years and EFS 27 ± 1%. In univariate analyses, age; serum LDH and ferritin; involvement of bone marrow, bone, liver or lung; and >1 metastatic system/compartment were associated with worse EFS. Tumour MNA was not associated with worse EFS. A multi-variable model and risk score incorporating age (>5 years, 2 points), serum LDH (>1250 U/L, 1 point) and number of metastatic systems (>1, 2 points) were developed. EFS was significantly correlated with risk score: EFS 52 ± 9% for score = 0 versus 6 ± 3% for score = 5 (P < 0.0001).

CONCLUSIONS

A simple score can identify an "ultra-high risk" (UHR) cohort (score = 5) comprising 8% of patients with 5-year EFS <10%. These patients appear not to benefit from induction therapy and could potentially be directed earlier to alternative experimental therapies in future trials.

Event-free survival of infants and toddlers enrolled in the HR-NBL-1/SIOPEN trial is associated with the level of neuroblastoma mRNAs at diagnosis

BACKGROUND

The purpose of this study was to evaluate whether levels of neuroblastoma mRNAs in bone marrow and peripheral blood from stage M infants (≤12 months of age at diagnosis, MYCN amplified) and toddlers (between 12 and 18 months, any MYCN status) predict event-free survival (EFS).

METHODS

Bone marrow aspirates and peripheral blood samples from 97 infants/toddlers enrolled in the European High-Risk Neuroblastoma trial were collected at diagnosis in PAXgene™ blood RNA tubes. Samples were analyzed by reverse transcription quantitative polymerase chain reaction according to standardized procedures.

RESULTS

Bone marrow tyrosine hydroxylase (TH) or paired-like homeobox 2b (PHOX2B) levels in the highest tertile were associated with worse EFS; hazard ratios, adjusted for age and MYCN status, were 1.5 and 1.8 respectively. Expression of both TH and PHOX2B in the highest tertile predicted worse outcome (p = 0.015), and identified 20 (23%) infants/toddlers with 5-year EFS of 20% (95%CI: 4%-44%). Prognostic significance was maintained after adjusting for over-fitting bias (p = 0.038), age and MYCN status. In peripheral blood, PHOX2B levels in the highest tertile predicted a two-fold increased risk of an event (p = 0.032), and identified 23 (34%) infants/toddlers with 5-year EFS of 29% (95%CI: 12%-48%). Time-dependent receiver operating characteristic analysis confirmed the prognostic value of combined TH and PHOX2B in bone marrow and of PHOX2B in peripheral blood during the first year of follow-up.

CONCLUSIONS

High levels of bone marrow TH and PHOX2B and of peripheral blood PHOX2B at diagnosis allow early identification of a group of high-risk infant and toddlers with neuroblastoma who may be candidates for alternative treatments. Integration with additional biomarkers, as well as validation in additional international trials is warranted.

Busulfan and melphalan versus carboplatin, etoposide, and melphalan as high-dose chemotherapy for high-risk neuroblastoma (HR-NBL1/SIOPEN): an international, randomised, multi-arm, open-label, phase 3 trial

BACKGROUND

High-dose chemotherapy with haemopoietic stem-cell rescue improves event-free survival in patients with high-risk neuroblastoma; however, which regimen has the greatest patient benefit has not been established. We aimed to assess event-free survival after high-dose chemotherapy with busulfan and melphalan compared with carboplatin, etoposide, and melphalan.

METHODS

We did an international, randomised, multi-arm, open-label, phase 3 cooperative group clinical trial of patients with high-risk neuroblastoma at 128 institutions in 18 countries that included an open-label randomised arm in which high-dose chemotherapy regimens were compared. Patients (age 1-20 years) with neuroblastoma were eligible to be randomly assigned if they had completed a multidrug induction regimen (cisplatin, carboplatin, cyclophosphamide, vincristine, and etoposide with or without topotecan, vincristine, and doxorubicin) and achieved an adequate disease response. Patients were randomly assigned (1:1) to busulfan and melphalan or to carboplatin, etoposide, and melphalan by minimisation, balancing age at diagnosis, stage, MYCN amplification, and national cooperative clinical group between groups. The busulfan and melphalan regimen comprised oral busulfan (150 mg/m2 given on 4 days consecutively in four equal doses); after Nov 8, 2007, intravenous busulfan was given (0·8-1·2 mg/kg per dose for 16 doses according to patient weight). After 24 h, an intravenous melphalan dose (140 mg/m2) was given. Doses of busulfan and melphalan were modified according to bodyweight. The carboplatin, etoposide, and melphalan regimen consisted of carboplatin continuous infusion of area under the plasma concentration-time curve 4·1 mg/mL per min per day for 4 days, etoposide continuous infusion of 338 mg/m2 per day for 4 days, and melphalan 70 mg/m2 per day for 3 days, with doses for all three drugs modified according to bodyweight and glomerular filtration rate. Stem-cell rescue was given after the last dose of high-dose chemotherapy, at least 24 h after melphalan in patients who received busulfan and melphalan and at least 72 h after carboplatin etoposide, and melphalan. All patients received subsequent local radiotherapy to the primary tumour site followed by maintenance therapy. The primary endpoint was 3-year event-free survival, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01704716, and EudraCT, number 2006-001489-17.

FINDINGS

Between June 24, 2002, and Oct 8, 2010, 1347 patients were enrolled and 676 were eligible for random allocation, 598 (88%) of whom were randomly assigned: 296 to busulfan and melphalan and 302 to carboplatin, etoposide, and melphalan. Median follow-up was 7·2 years (IQR 5·3-9·2). At 3 years, 146 of 296 patients in the busulfan and melphalan group and 188 of 302 in the carboplatin, etoposide, and melphalan group had an event; 3-year event-free survival was 50% (95% CI 45-56) versus 38% (32-43; p=0·0005). Nine patients in the busulfan and melphalan group and 11 in the carboplatin, etoposide, and melphalan group had died without relapse by 5 years. Severe life-threatening toxicities occurred in 13 (4%) patients who received busulfan and melphalan and 29 (10%) who received carboplatin, etoposide, and melphalan. The most frequent grade 3-4 adverse events were general condition (74 [26%] of 281 in the busulfan and melphalan group vs 103 [38%] of 270 in the carboplatin, etoposide, and melphalan group), infection (55 [19%] of 283 vs 74 [27%] of 271), and stomatitis (138 [49%] of 284 vs 162 [59%] of 273); 60 (22%) of 267 patients in the busulfan and melphalan group had Bearman grades 1-3 veno-occlusive disease versus 21 (9%) of 239 in the carboplatin, etoposide, and melphalan group.

INTERPRETATION

Busulfan and melphalan improved event-free survival in children with high-risk neuroblastoma with an adequate response to induction treatment and caused fewer severe adverse events than did carboplatin, etoposide, and melphalan. Busulfan and melphalan should thus be considered standard high-dose chemotherapy and ongoing randomised studies will continue to aim to optimise treatment for high-risk neuroblastoma.

FUNDING

European Commission 5th Framework Grant and the St Anna Kinderkrebsforschung.

The state of research into children with cancer across Europe: new policies for a new decade

Overcoming childhood cancers is critically dependent on the state of research. Understanding how, with whom and what the research community is doing with childhood cancers is essential for ensuring the evidence-based policies at national and European level to support children, their families and researchers. As part of the European Union funded EUROCANCERCOMS project to study and integrate cancer communications across Europe, we have carried out new research into the state of research in childhood cancers. We are very grateful for all the support we have received from colleagues in the European paediatric oncology community, and in particular from Edel Fitzgerald and Samira Essiaf from the SIOP Europe office. This report and the evidence-based policies that arise from it come at a important junction for Europe and its Member States. They provide a timely reminder that research into childhood cancers is critical and needs sustainable long-term support.

Excellent outcome with reduced treatment in infants with nonmetastatic and unresectable neuroblastoma without MYCN amplification: results of the prospective INES 99.1

PURPOSE

To evaluate the efficacy of low-dose chemotherapy in infants with nonmetastatic and unresectable neuroblastoma (NB) without MYCN amplification.

PATIENTS AND METHODS

Infants with localized NB and no MYCN amplification were eligible in the SIOPEN Infant Neuroblastoma European Study 99.1 study. Primary tumor was deemed unresectable according to imaging defined risk factors. Diagnostic procedures and staging were carried out according to International Staging System recommendations. Children without threatening symptoms received low-dose cyclophosphamide (5 mg/kg/d × 5 days) and vincristine (0.05 mg/kg at day 1; CyV), repeated once to three times every 2 weeks until surgical excision could be safely performed. Children with either one threatening symptom or insufficient response to CyV were given carboplatin and etoposide (CaE), sometimes followed by vincristine, cyclophosphamide, and doxorubicin. No postoperative treatment was to be administered.

RESULTS

Between December 1999 and April 2004, 120 infants were included in the study. Eighty-eight had no threatening symptoms and 79 received CyV. CaE was given to 49 of them because of insufficient response. Thirty-two children had threatening symptoms, 30 of whom received CaE. Anthracyclines were given to 46 children. Surgery was attempted in 102 patients, leading to gross surgical excision in 93. Relapse occurred in 12 patients (nine local and three metastatic). Five-year overall and event-free survivals were 99% ± 1% and 90% ± 3%, respectively, with a median follow-up of 6.1 years (range, 1.6 to 9.1).

CONCLUSION

Low-dose chemotherapy without anthracyclines is effective in 62% of infants with an unresectable NB and no MYCN amplification, allowing excellent survival rates without jeopardizing their long-term outcome.

Hypermethylation of apoptotic genes as independent prognostic factor in neuroblastoma disease

Neuroblastoma (NB) is an embryonal tumour of neuroectodermal cells, and its prognosis is based on patient age at diagnosis, tumour stage and MYCN amplification, but it can also be classified according to their degree of methylation. Considering that epigenetic aberrations could influence patient survival, we studied the methylation status of a series of 17 genes functionally involved in different cellular pathways in patients with NB and their impact on survival. We studied 82 primary NB tumours and we used methylation-specific-PCR to perform the epigenetic analysis. We evaluated the putative association among the evidence of hypermethylation with the most important NB prognostic factors, as well as to determine the relationship among methylation, clinical classification and survival. CASP8 hypermethylation showed association with relapse susceptibility and, TMS1 and APAF1 hypermethylation are associated with bad prognosis and showed high influence on NB overall survival. Hypermethylation of apoptotic genes has been identified as a good candidate of prognostic factor. We propose the simultaneous analysis of hypermethylation of APAF1, TMS1 and CASP8 apoptotic genes on primary NB tumour as a good prognostic factor of disease progression.

Epigenetic alterations in disseminated neuroblastoma tumour cells: influence of TMS1 gene hypermethylation in relapse risk in NB patients

PURPOSE

Most neuroblastoma patients over 18 months of age at diagnosis present disseminated disease. The presence of neuroblastoma cells in bone marrow can be used to evaluate the response to treatment. It is possible that alterations in certain tumour cells might confer a selective advantage over tumour dissemination process, and probably be helpful in the clonal selection of tumour-specific cells that could originate metastasis.

METHODS

We performed real-time quantitative PCR to identify the presence of disseminated tumour cells in bone marrow samples, and we used MSP to analyse the methylation profile of 20 genes putatively implied in dissemination.

RESULTS

We described epigenetic alterations in the methylated status of certain genes in disseminated tumour cells from bone marrow. Those cases with high rate of hypermethylation showed an increased probability of relapse during or after treatment. We found significantly poor prognosis in event-free survival in cases with hypermethylation of TMS1, MGMT and RARbeta2 genes.

CONCLUSION

We could not confirm the presence of a specific methylation profile in disseminated neuroblastoma tumour cells, but a high accumulation of epigenetic events in those cells is associated with a high risk of relapse, independently of MYCN amplification.

Poor Survival for Infants WithMYCN-Amplified Metastatic Neuroblastoma Despite Intensified Treatment: The International Society of Paediatric Oncology European Neuroblastoma Experience

Purpose

To report the results of a prospective, nonrandomized European study on infants with neuroblastoma and MYCN gene amplification.

Patients and Methods

Infants with neuroblastoma (stage 2, 3, 4, and 4s) and MYCN gene amplification who were diagnosed between 1999 and 2004 were eligible for enrollment onto the study. After diagnosis, staging, and mandatory biologic studies, induction chemotherapy (IC) with conventional drugs was administered, followed by delayed surgery, megatherapy (busulfan-melphalan as a conditioning regimen), and local radiotherapy.

Results

Of the 46 infants enrolled onto the study, 35 infants were eligible; of these 35 infants, 97% had metastatic spread (24 infants had stage 4, and 10 infants had stage 4s). Two-year overall survival (OS) was 30% (SE, 0.08), with median survival time of 12 months, and 23 deaths due to disease. Two-year, event-free survival (EFS) was 29% (SE, 0.07). The treatment was well tolerated with no deaths as a result of toxicity or severe toxicity. Despite protocol adherence, 30% of the patients who were assessable for response to IC experienced disease progression or did not respond. Stage and high lactate dehydrogenase reached significance in the univariate analysis (P = .028 and .039, respectively for OS; and P = .05 and .031 respectively, for EFS). Ten of 16 patients who received megatherapy are still alive.

Conclusion

Although treatment was well tolerated, survival was poor and our IC failed to achieve a satisfactory response in 30% of our patients. New therapeutic approaches and more intense world-wide collaboration are needed to achieve a cure in this population.

Subtelomeric analysis of pediatric astrocytoma: subchromosomal instability is a distinctive feature of pleomorphic xanthoastrocytoma

Astrocytic neoplasms are genetically heterogeneous; however a low frequency of genomic changes has been found in juvenile pilocytic astrocytoma (PA) in molecular studies. Concerning pleomorphic xanthoastrocytomas (PXA), recent studies have given heterogeneous results for chromosomal alterations. We studied the subtelomeric regions of 19 primary astrocytoma tumors. Results were near normality for the PA group with relative scarcity of chromosomal imbalances, except for the duplication of 3pter in 4/15 and deletion of 21qter in 5/15 of them. In contrast, a specific profile was observed in the 4 PXA tumoral samples. This involved 3pter, 14qter and 19pter duplication and 4qter, 6qter, 9qter, 13cen, 17pter, 18qter and 21qter deletion. Our results indicate that the chromosomal and genetic aberrations in PXAs differed from those typically associated with the diffusely infiltrating astrocytic and oligodendroglial gliomas. These genetic differences would likely contribute to the more favorable behavior of PXAs and may be helpful for molecular differential diagnosis of pediatric cerebral tumors.

Formal hydride transfer mechanism for photoreduction of 3-phenylquinoxalin-2-ones by amines. Association Of 3-phenylquinoxalin-2-one with aliphatic amines

The photophysical and photochemical behavior of 1-methyl-3-phenylquinoxalin-2-one (MeNQ) and 3-phenylquinoxalin-2-one (HNQ) in the presence of amines is reported. While HNQ fluorescence shows an auxochromic effect and a bathochromic shift with added amines, explained by association of HNQ with amine in the ground state and emission from both excited species HNQ and [HNQ-amine], both MeNQ and HNQ are photoreduced efficiently on irradiation in the presence of amines, leading to the semireduced quinoxalin-2-ones, MeNQH(-) and HNQH(-), respectively, via an electron-proton-electron transfer, with unit quantum yields at high amine concentrations. The semireduced quinoxalin-2-ones XNQH(-) (X = H, Me) revert almost quantitatively to the parent XNQ in a dark thermal reaction with an activation free energy for MeNQH(-) of 17.4 and 25.9 kcal/mol in acetonitrile and benzene, respectively. Kinetic and spectroscopic (UV and NMR) evidence supports the proposed reaction mechanism for the reversible photoreduction.

Anti-G(D2) antibody treatment of minimal residual stage 4 neuroblastoma diagnosed at more than 1 year of age

PURPOSE

To eradicate minimal residual disease with anti-G(D2) monoclonal antibody 3F8 in stage 4 neuroblastoma (NB) diagnosed at more than 1 year of age.

PATIENTS AND METHODS

Thirty-four patients were treated with 3F8 at the end of chemotherapy. Most had either bone marrow (n=31) or distant bony metastases (n=29). Thirteen patients were treated at second or subsequent remission (group I) and 12 patients in this group had a history of progressive/persistent disease after bone marrow transplantation (BMT); 21 patients were treated in first remission following N6 chemotherapy (group II).

RESULTS

Before 3F8 treatment, 23 patients were in complete remission CR, eight in very good partial remission (VGPR), one in partial remission (PR), and two had microscopic foci in marrow. Twenty-five had evidence of NB by at least one measurement of occult/minimal tumor (iodine 131[(131)I]-3F8 imaging, marrow immunocytology, or marrow reverse-transcriptase polymerase chain reaction [RT-PCR]). Acute self-limited toxicities of 3F8 treatment were severe pain, fever, urticaria, and reversible decreases in blood counts and serum complement levels. There was evidence of response by immunocytology (six of nine), by GAGE RT-PCR (seven of 12), and by (131)I-3F8 scans (six of six). Fourteen patients are alive and 13 (age 1.8 to 7.4 years at diagnosis) are progression-free (40 to 130 months from the initiation of 3F8 treatment) without further systemic therapy, none with late neurologic complications. A transient anti-mouse response or the completion of four 3F8 cycles was associated with significantly better survival.

CONCLUSION

Despite high-risk nature of stage 4 NB, long-term remission without autologous (A)BMT can be achieved with 3F8 treatment. Its side effects were short-lived and manageable. The potential benefits of 3F8 in consolidating remission warrant further investigations.

Intracranial ependymomas in children: a critical review of prognostic factors and a plea for cooperation

BACKGROUND

Current controversies in pediatric intracranial ependymoma include histologic categorization and management. Most of our knowledge of this disease comes from single-institution reports.

METHODS

A literature search was done, covering the period 1976-1996. The aim of this review is to analyze the prognostic factors reported in the literature over the last 20 years.

RESULTS

Forty-five series were reviewed, including more than 1,400 children. The largest series reported on 92 patients, and the accrual rate ranged from 0.32-12 patients per year. None of the prognostic factors reported achieved a consensus throughout the different series. Histology remains a major issue, and the range in the incidence of anaplastic ependymo mas (7-89%) highlights the difficulty in agreeing on a histological grading system. The role of surgery on the outcome seems to be determinant. Recent series based on homogeneous imaging-documented extents of resection strongly support the benefit of postoperative radiotherapy. The lack of a proven, effective chemotherapy regimen precludes its use except in prospective pilot studies.

CONCLUSIONS

Limited information is available from single-institution reports in ependymoma. Only large national or international studies can provide enough information to allow a multivariate analysis of the prognostic factors, and thus lead to new therapeutic proposals.

Quantitative studies of monoclonal antibody targeting to disialoganglioside GD2 in human brain tumors

Iodine-131 3F8, a murine IgG3 monoclonal antibody that targets to GD2-bearing tumors, was administered intravenously to 12 patients with brain tumors. Six patients received 2 mCi (0.74 Bq) of 131I-3F8, five patients 10 mCi (3.7 Bq)/1.73 m2 of 131I-3F8, and one patient 2.6 mCi (0.96 Bq) of 124I-3F8, with no side-effects. Nine of 11 malignant gliomas and the single metastatic melanoma showed antibody localization, with the best tumor delineation on single-photon emission tomography (SPET) following 10 mCi (3.7 Bq)/1.73 m2 dose. No nonspecific uptake in the normal craniospinal axis was detected. There was no difference in the pharmacokinetics of low-dose versus the higher-dose antibody groups; plasma and total-body half-lives were 18 h and 49 h, respectively. Surgical sampling and time-activity curves based on quantitative imaging showed peak uptake in high-grade glioma at 39 h, with a half-life of 62 h. Tumor uptake at time of surgery averaged 3.5 x 10(-3) %ID/g and peak activity by the conjugate view method averaged 9.2 x 10(-3) %ID/g (3.5-17.8). Mean radiation absorption dose was 3.9 rad per mCi injected (range 0.7-9.6) or 10.5 cGy/Bq (range 1.9-26). There was agreement on positive sites when immunoscintigraphy was compared with technetium-99m glucoheptonate/diethylene triamine penta-acetic acid planar imaging, thallium-201 SPET, and fluorine-18 fluorodeoxyglucose positron emission tomography. Taken together, these data suggest that quantitative estimates of antibody targeting to intracranial tumors can be made using the modified conjugate view method.

Antibody response to murine anti-GD2 monoclonal antibodies: correlation with patient survival

Clinical strategies which modulate the human anti-mouse antibody response (HAMA) in patients may have a profound influence on the idiotype network inducible by murine monoclonal antibodies (MoAb). Prior to myeloablative chemotherapy (ABMT), 9 patients with Stage IV neuroblastoma were imaged with 131I-3F8, a MoAb specific for the ganglioside GD2. Their serum HAMA, anti-idiotypic, anti-GD2, and anti-anti-idiotypic antibodies were assayed by enzyme-linked immunosorbent assay prior to, and at 3 and 6 months postimaging. HAMA and anti-idiotypic levels remained low, in contrast to the high levels in 10 patients imaged with 131I-3F8 without ABMT. Five of the 9 patients are long-term survivors; all had elevated anti-GD2 and anti-anti-idiotypic levels, significantly higher than those who died of disease. Although 131I-3F8 imaging prior to ABMT detected abnormal sites in 4 of 9 patients, 3 of the 4 patients have continued in remission for 24-63 months after ABMT, and all 3 mounted anti-GD2 and anti-anti-idiotypic antibody responses. We conclude that myeloablative therapy strongly suppressed the HAMA/anti-idiotypic response to murine MoAb and that the prognostic significance of host immune response to ganglioside GD2 MoAb deserves further investigation.

Disialoganglioside GD2 anti-idiotypic monoclonal antibodies

Disialoganglioside GD2 is widely expressed among neuroblastomas, melanomas, small-cell lung carcinoma, sarcomas and brain tumors. Immunity directed against this antigen may have anti-tumor utility. Since GD2 is poorly immunogenic, anti-idiotypic antibodies may serve as alternative tumor vaccines. Monoclonal antibody 3F8, a murine IgG3 specific for GD2, has shown excellent tumor-targeting ability in vitro and in vivo. LOU/CN rats were immunized with 3F8 and their spleens were used in somatic-cell hybridization, using SP2/0, P3 and Y3 as fusion partners. Six anti-idiotypic (anti-id) MAbs (C2D8, Idio-2, AIG4, C2H7, C4E4, A2A6) were selected based on their reactivity with 3F8 and non-reactivity with murine IgG3 myelomas. Specificity of each anti-id was demonstrated by using various ELISA: (i) lack of direct binding to solid phase myelomas and serum proteins; (ii) inability of other myelomas to inhibit anti-id binding to 3F8; (iii) absence of cross-reactivity of other myelomas to solid-phase anti-id; (iv) lack of inhibition by anti-id of binding of other ganglioside antibodies to their antigens. Antigen specificity was further examined by inhibition of binding of 3F8 to GD2 on immuno-thin-layer chromatography, and by inhibition of 3F8 immunostaining of neuroblastoma cell lines. These 6 antibodies were demonstrated to be distinct, in view of their cross-reactivity, fusion partners and relative strength of binding to 3F8. Anti-GD2 antibodies were induced after immunization with these anti-id antibodies in C57Bl/6 mice. These rat anti-3F8-idiotypic antibodies with exquisite specificity for anti-GD2 antibodies may be useful in vaccine construction.