Treatment of children with favorable histology Wilms tumor with extrapulmonary metastases: A report from the COG studies AREN0533 and AREN03B2 and NWTSG study NWTS-5

BACKGROUND

Patients with stage IV favorable histology Wilms tumor (FHWT) with extrapulmonary metastases (EPM) constitute a small subset of patients with FHWT. Because of their rarity and heterogeneity, optimal FHWT treatment is not well understood. Children's Oncology Group protocol AREN0533 assigned patients with FHWT and EPM to intensified chemotherapy, regimen M, after initial DD-4A chemotherapy. To improve understanding of prognostic factors and best therapies, experiences of patients with EPM on AREN0533, as well as on protocols AREN03B2 and NWTS-5, were reviewed.

METHODS

Combined outcomes for patients with EPM from NWTS-5, AREN0533, and AREN03B2 were determined. Those treated on AREN0533 were compared with those treated on NWTS-5. Prognostic factors were explored in the pooled cohort.

RESULTS

Forty-seven patients with FHWT with EPM enrolled on AREN0533, 37 enrolled on NWTS-5, and 64 were followed only on AREN03B2. The pooled cohort of all 148 patients demonstrated a 4-year event-free survival (EFS) of 77.3% (95% CI, 70.8-84.4) and 4-year overall survival of 88.9% (95% CI, 83.9-94.2). Four-year EFS of patients with EPM treated on AREN0533 was 76.0% (95% CI, 64.6-89.4) vs 64.9% (95% CI, 51.7-82.2) on NWTS-5; hazard ratio, 0.64, p = .26; no difference in overall survival was observed. Increasing linear age and slow incomplete lung response were associated with worse EFS in a pooled cohort.

CONCLUSIONS

Outcomes for patients with EPM are among the lowest for children with FHWT. Further trials with standardized surgical and radiation treatment to metastatic sites, and prospectively collected biologic and treatment details are needed.

CLINICAL TRIAL REGISTRATION

Clinical Trials.gov identifiers: NCT00379340, NCT00898365, and NCT00002611.

Prognostic impact of lymph node involvement and loss of heterozygosity of 1p or 16q in stage III favorable histology Wilms tumor: A report from Children's Oncology Group Studies AREN03B2 and AREN0532

INTRODUCTION

The prognostic impact of positive lymph nodes (LN+) and/or singular loss of heterozygosity (LOH) of 1p or 16q were assessed in children with stage III favorable histology Wilms tumor (FHWT) enrolled on AREN0532 or AREN03B2 alone.

PATIENTS AND METHODS

A total of 635 stage III FHWT vincristine/dactinomycin/doxorubicin (DD4A)-treated patients met inclusion criteria. Event-free survival (EFS) and overall survival are reported overall and by LN sampling, LN status, LOH 1p, LOH 16q, and a combination of LN status and singular LOH. Patients with unknown or positive combined LOH of 1p and 16q status and AREN03B2-only patients with unknown outcomes or treatment other than DD4A were excluded.

RESULTS

EFS did not differ by study, supporting pooling. Lack of LN sampling (hazard ratio [HR], 2.12; p = .0037), LN positivity (HR, 2.78; p = .0002), LOH 1p (HR, 2.18; p = .0067), and LOH 16q (HR, 1.72; p = .042) were associated with worse EFS. Compared with patients with both LN- and LOH-, those with negative nodes but positive LOH 1p or 16q and those with LN+ but LOH- for 1p or 16q had significantly worse EFS (HR, 3.05 and 3.57, respectively). Patients positive for both LN and LOH had the worst EFS (HR, 6.33; overall group factor, p < .0001).

CONCLUSION

Findings confirm LN+ status as an adverse prognostic factor amplified by presence of singular LOH 1p or 16q, supporting study of intensified therapy for patients with LN+ in combination with singular LOH in a prospective clinical trial.

The Trilogy of SARS-CoV-2 in Pediatrics (Part 3): Thrombosis, Anticoagulant, and Antiplatelet Considerations

The hypercoagulable state induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects all patients regardless of age. The incidence of venous thromboembolism in pediatric patients with SARS-CoV-2-related illnesses is not well established. Although deep vein thrombosis is rare in children in the absence of risk factors, coagulopathy and the development of thromboses have been described in pediatric patients with acute COVID-19 and multisystem inflammatory syndrome. This comprehensive review provides a detailed overview of SARS-CoV-2-associated coagulopathy as well as strategies for optimizing the evaluation, management, and prevention of thrombosis in pediatric patients.

AZ64 inhibits TrkB and enhances the efficacy of chemotherapy and local radiation in neuroblastoma xenografts

Neuroblastoma is a common pediatric tumor characterized by clinical heterogeneity. Because it is derived from sympathetic neuroblasts, the NTRK family of neurotrophin receptors plays an integral role in neuroblastoma cell survival, growth, and differentiation. Indeed, high expression of NTRK1 is associated with favorable clinical features and outcome, whereas expression of NTRK2 and its ligand, brain-derived neurotrophic factor (BDNF), are associated with unfavorable features and outcome. AZ64 (Astra Zeneca) is a potent and selective inhibitor of the NTRK tyrosine kinases that blocks phosphorylation at nanomolar concentrations. To determine the preclinical activity of AZ64, we performed intervention trials in a xenograft model with NTRK2-overexpressing neuroblastomas. AZ64 alone significantly inhibited tumor growth compared to vehicle-treated animals (p = 0.0006 for tumor size). Furthermore, the combination of AZ64 with conventional chemotherapeutic agents, irinotecan and temozolomide (irino-temo), showed significantly enhanced anti-tumor efficacy compared to irino-temo alone [(p < 0.0001 for tumor size, p < 0.0005 for event-free survival (EFS)]. We also assessed the combination of AZ64 and local radiation therapy (RT) on a neuroblastoma hindlimb xenograft model, and the efficacy of local RT was significantly increased when animals were treated simultaneously with AZ64 (p < 0.0001 for tumor size, p = 0.0006 for EFS). We conclude that AZ64 can inhibit growth of NTRK-expressing neuroblastomas both in vitro and in vivo. More importantly, it can significantly enhance the efficacy of conventional chemotherapy as well as local RT, presumably by inhibition of the NTRK2/BDNF autocrine survival pathway.

Trk receptor expression and inhibition in neuroblastomas

Neuroblastoma, the most common and deadly solid tumor in children, exhibits heterogeneous clinical behavior, from spontaneous regression to relentless progression. Current evidence suggests that the TRK family of neurotrophin receptors plays a critical role in these diverse behaviors. Neuroblastomas expressing TrkA are biologically favorable and prone to spontaneous regression or differentiation, depending on the absence or presence of its ligand (NGF) in the microenvironment. In contrast, TrkB-expressing tumors frequently have MYCN amplification and are very aggressive and often fatal tumors. These tumors also express the TrkB ligand (BDNF), resulting in an autocrine or paracrine survival pathway. Exposure to BDNF promotes survival, drug resistance, and angiogenesis of TrkB-expressing tumors. Here we review the role of Trks in normal development, the different functions of Trk isoforms, and the major Trk signaling pathways. We also review the roles these receptors play in the heterogeneous biological and clinical behavior of neuroblastomas, and the activation of Trk receptors in other cancers. Finally we address the progress that has been made in developing targeted therapy with Trk-selective inhibitors to treat neuroblastomas and other tumors with activated Trk expression.

Acral erythema with oral methotrexate in a child

Acral erythema is a rare cutaneous reaction that has been associated with various chemotherapy regimens. Most occurrences have been described in adult patients. Recently, methotrexate has been implicated in the development of acral erythema; however, pediatric reports are few. All of the reports in the pediatric and adult literature have described patients receiving moderate to high-dose intravenous methotrexate. Here, we describe an instance of standard-dose oral methotrexate-associated acral erythema in a young girl with acute lymphoblastic leukemia, and review the recent literature as it relates to pediatric patients.

Heregulin-induced apoptosis

Heregulins (HRGs) are a group of polypeptide factors that are encoded by four different HRG genes that can express multiple isoforms through alternate RNA splicing. A number of HRG isoforms possess both growth stimulatory and growth inhibitory functions that are necessary for their important role in the development and maintenance of the heart, nervous system and epithelial cells in multiple organs including the breast. Growth inhibition by HRG relates to its ability to induce apoptosis, differentiation, and cell cycle G(2) arrest. Current studies suggest that HRGs can induce a unique form of apoptosis. In this article, we review recent progress in characterizing and understanding HRG-induced apoptosis. Particular attention has been given to: (1). the activation of caspases-7 and -9; (2). the role of the anti-apoptotic Bcl-2 protein; and (3). the signaling molecules and pathways that regulate HRG-induced apoptosis, including the p38, JNK, mTOR kinase, and PKC alpha kinase.

Additive effects of ciliary neurotrophic factor and testosterone on motoneuron survival; differential effects on motoneuron size and muscle morphology

Testosterone and ciliary neurotrophic factor (CNTF) each enhance motoneuron survival in the spinal nucleus of the bulbocavernosus (SNB) of newborn rats. Here we directly compared the effects of CNTF and testosterone, alone and in combination, on SNB motoneuron number, SNB cell size, and morphology of the levator ani (LA) target muscle. Female rat pups were treated daily from postnatal day 1 through 6 (P1-P6) with recombinant human CNTF (hCNTF), testosterone propionate (TP), both hCNTF and TP, or neither. Effects of treatment were assessed on P7. TP and hCNTF each increased the number of SNB motoneurons and did so to a similar degree. Females treated with both hCNTF and TP had significantly more SNB cells than those receiving either hCNTF or TP alone. TP administered from P1 to P6 also increased SNB motoneuron size on P7. In contrast, hCNTF alone did not significantly affect SNB cell size, and hCNTF in combination with TP antagonized the effect of TP on motoneuron size. TP also increased LA muscle fiber number and LA fiber size, whereas hCNTF did not significantly influence LA muscle morphology in this study. Immunohistochemistry established that virtually all SNB motoneurons of both males and females express the CNTF alpha receptor (CNTFRalpha) between embryonic day 20 and postnatal day 6. Thus, effects of TP and hCNTF on SNB motoneuron survival were additive, and increases in motoneuron survival were dissociated from changes in target muscle morphology in hCNTF-treated animals. SNB motoneurons express CNTFRalpha perinatally and are therefore potential direct sites of hCNTF action.