Purpose: Anti-GD2 mAbs, acting via antibody-dependent cell-mediated cytotoxicity, may enhance the effects of chemotherapy. This pilot trial investigated a fixed dose of a unique anti-GD2 mAb, hu14.18K322A, combined with chemotherapy, cytokines, and haploidentical natural killer (NK) cells. Experimental Design: Children with recurrent/refractory neuroblastoma received up to six courses of hu14.18K322A (40 mg/m2/dose, days 2–5), GM-CSF, and IL2 with chemotherapy: cyclophosphamide/topotecan (courses 1,2), irinotecan/temozolomide (courses 3,4), and ifosfamide/carboplatin/etoposide (courses 5,6). Parentally derived NK cells were administered with courses 2, 4, and 6. Serum for pharmacokinetic studies of hu14.18K322A, soluble IL2 receptor alpha (sIL2Rα) levels, and human antihuman antibodies (HAHA) were obtained. Results: Thirteen heavily pretreated patients (9 with prior anti-GD2 therapy) completed 65 courses. One patient developed an unacceptable toxicity (grade 4 thrombocytopenia >35 days). Four patients discontinued treatment for adverse events (hu14.18K322A allergic reaction, viral infection, surgical death, second malignancy). Common toxicities included grade 3/4 myelosuppression (13/13 patients) and grade 1/2 pain (13/13 patients). Eleven patients received 29 NK-cell infusions. The response rate was 61.5% (4 complete responses, 1 very good partial response, 3 partial responses) and five had stable disease. The median time to progression was 274 days (range, 239–568 days); 10 of 13 patients (77%) survived 1 year. Hu14.18K322A pharmacokinetics was not affected by chemotherapy or HAHA. All patients had increased sIL2Rα levels, indicating immune activation. Conclusions: Chemotherapy plus hu14.18K322A, cytokines, and NK cells is feasible and resulted in clinically meaningful responses in patients with refractory/recurrent neuroblastoma. Further studies of this approach are warranted in patients with relapsed and newly diagnosed neuroblastoma. Clin Cancer Res; 23(21); 6441–9. ©2017 AACR.

Background: Most prior studies evaluating subsequent malignant neoplasms (SMNs) in patients with neuroblastoma are restricted to long-term survivors and/or their treatment exposures. This study investigates SMNs in patients diagnosed with neuroblastoma at our institution. Methods: Records of 646 patients treated for neuroblastoma at St Jude Children’s Research Hospital between 1961 and 2005 were reviewed. Data from patients with SMNs were analyzed and the 20- and 30-year cumulative incidence of SMNs and standardized incidence ratio were calculated. Results: Twenty-one patients had a SMN. The 20- and 30-year cumulative incidences of a SMN were 2.6%±0.7% and 4.6%±1.1%, respectively. The standardized incidence ratio was 8.3 (95% confidence interval, 5.0-13.0). Five patients developed a SMN within 5 years from diagnosis. The median latency for the development of acute myeloid leukemia/myelodysplastic syndrome (n=4), sarcomas (n=7), and carcinomas (n=5) were 3.6, 9, and 24.2 years, respectively. Nine patients died from their SMN, including all with acute myeloid leukemia/myelodysplastic syndrome. Conclusions: Patients with neuroblastoma have an increased risk of secondary neoplasia. Modification of risk-adapted therapies will likely alter the affected patient population and the incidence of SMNs. Future studies are necessary to link SMNs to treatment exposures and to evaluate the risk of SMNs beyond 30 years from diagnosis.

DNA damage response inhibitors have a potentially important therapeutic role in paediatric cancers; however, their optimal use, including patient selection and combination strategy, remains unknown. Moreover, there is an imbalance between the number of drugs with diverse mechanisms of action and the limited number of paediatric patients available to be enrolled in early-phase trials, so prioritisation and a strategy are essential. While PARP inhibitors targeting homologous recombination-deficient tumours have been used primarily in the treatment of adult cancers with BRCA1/2 mutations, BRCA1/2 mutations occur infrequently in childhood tumours, and therefore, a specific response hypothesis is required. Combinations with targeted radiotherapy, ATR inhibitors, or antibody drug conjugates with DNA topoisomerase I inhibitor-related warheads warrant evaluation. Additional monotherapy trials of PARP inhibitors with the same mechanism of action are not recommended. PARP1-specific inhibitors and PARP inhibitors with very good central nervous system penetration also deserve evaluation. ATR, ATM, DNA-PK, CHK1, WEE1, DNA polymerase theta and PKMYT1 inhibitors are early in paediatric development. There should be an overall coordinated strategy for their development. Therefore, an academia/industry consensus of the relevant biomarkers will be established and a focused meeting on ATR inhibitors (as proof of principle) held. CHK1 inhibitors have demonstrated activity in desmoplastic small round cell tumours and have a potential role in the treatment of other paediatric malignancies, such as neuroblastoma and Ewing sarcoma. Access to CHK1 inhibitors for paediatric clinical trials is a high priority. The three key elements in evaluating these inhibitors in children are (1) innovative trial design (design driven by a clear hypothesis with the intent to further investigate responders and non-responders with detailed retrospective molecular analyses to generate a revised or new hypothesis); (2) biomarker selection and (3) rational combination therapy, which is limited by overlapping toxicity. To maximally benefit children with cancer, investigators should work collaboratively to learn the lessons from the past and apply them to future studies. Plans should be based on the relevant biology, with a focus on simultaneous and parallel research in preclinical and clinical settings, and an overall integrated and collaborative strategy.