A phase I window, dose escalating and safety trial of metformin in combination with induction chemotherapy in relapsed refractory acute lymphoblastic leukemia: Metformin with induction chemotherapy of vincristine, dexamethasone, PEG-asparaginase, and doxorubicin

BACKGROUND

Acute lymphoblastic leukemia (ALL) remains a major cause of death in children. AMP-activated protein kinase (AMPK) affects the unfolded protein response (UPR), leading to increased vulnerability to endoplasmic reticulum (ER) stress in ALL cells. In vitro, metformin causes ALL cell death via AMPK-mediated inhibition of the UPR. It was evaluated whether ER stress could be induced in relapsed ALL through a phase I study investigating the safety and feasibility of metformin in combination with relapse induction chemotherapy.

PROCEDURE

Metformin was administered twice daily for 28 days in addition to vincristine, dexamethasone, PEG-asparaginase and doxorubicin (VXLD). Dose escalation of metformin was evaluated using a 3+3 design. Pharmacokinetics (PK), pharmacodynamic (PD) evaluation of the AMPK and ER stress/UPR pathways, and treatment response were assessed.

RESULTS

Fourteen patients were enrolled; all were evaluable for toxicity. The recommended phase 2 dose (RP2D) was Dose level 2, 1,000 mg/m² /day. A single dose-limiting toxicity (DLT), hypoglycemia with acidosis, was observed at the RP2D and two DLTs, diarrhea and acidosis, were observed at Dose Level 3. Nine patients were evaluable for response as defined by the protocol, receiving at least 85% of planned metformin doses. Five complete remissions, one partial response, and one stable disease were observed. PD evaluation showed induction of ER stress, activation of AMPK, and inhibition of the UPR.

CONCLUSIONS

The VXLD with metformin was tolerable with a RP2D for metformin of 1,000 mg/m² /day and yielded responses in a heavily pretreated population. ER stress was induced and toxicities attributable to metformin occurred in all dose levels.

Abstract 5872: Pediatric Preclinical Testing Consortium (PPTC) of eribulin in osteosarcoma (OS) patient-derived xenograft (PDX) models

Introduction: Eribulin is a synthetic analogue of halichondrin B and inhibits cancer cell proliferation via blockade of microtubule function. It is FDA approved for patients with breast cancer with two prior chemotherapy regimens for the treatment of metastatic disease and for previously treated patients with inoperable or metastatic liposarcoma. In vivo testing of eribulin against osteosarcoma (OS) Pediatric Preclinical Testing Program (PPTP) PDX models, developed from primary tumors, demonstrated significant single-agent activity. However, a Children's Oncology Group (COG) phase 2 trial of eribulin in patients with relapsed OS did not demonstrate significant antitumor activity of single-agent eribulin. In the current study the efficacy of eribulin in PDX models generated from primary and relapsed tumors, as well as dose-response, were assessed.

Methods: Eribulin was evaluated in 6 PPTC models, 4 from primary OS specimens (OS46, OS51, OS55, OS56) and 2 from relapsed specimens (OS39R, OS60). Eribulin was administered via intraperitoneal (IP) injection at a dose of 1mg/kg on days 1 and 4, repeated every 21 days. Response to treatment was determined based on PPTP-established endpoints (1). In addition, 3 dose levels of eribulin were evaluated in 3 PPTP models developed from primary tumors (OS1, OS17, OS33) and 1 model developed from a relapsed tumor (OS60). In the dose-response studies, eribulin was administered IP at 1mg/kg, 0.5mg/kg and 0.25mg/kg on days 1 and 4, repeated every 21 days with follow-up through day 42.

Results: Eribulin at a dose level of 1mg/kg induced stable disease (SD) or partial response (PR) in 4/9 and 3/9 OS xenografts, respectively. SD/PR responses were observed in PDX models generated from primary tumors (5/7) as well as PDX models generated from relapsed tumors (2/2). Eribulin demonstrated maximal antitumor activity at the highest dose level, 1mg/kg (SD/PR in 3/4). At 0.5 mg/kg 1/4 models achieved SD/PR, and at 0.25mg/kg all 4 models showed progressive disease within the 6-week testing period. Minimum relative tumor volumes also showed a dose-response effect from 0.25 to 1.0 mg/kg.

Conclusions: Eribulin demonstrated antitumor activity against OS PDX models generated from primary and relapsed tumors at a dose level of 1mg/kg. Eribulin showed a clear dose-response effect in terms of its ability to induce SD/PR responses, highlighting the importance of dose selection. This dose-response effect suggests that an inability to achieve comparable serum drug concentrations in human clinical trials may explain the limited tumor responses observed in the COG phase 2 trial of eribulin. Pharmacokinetic studies from the COG phase 2 study are ongoing in an effort to understand the disparate tumor responses seen in the in vivo studies and the phase 2 clinical trial.

Reference: 1. Houghton PJ et al. Pediatr Blood Cancer 2007;49:928-40.

Supported by NCI Grants: CA199222, CA199221.

Citation Format: Wendong Zhang, E. Anders Kolb, Richard Gorlick, Michael Roth, Jonathan Gill, Sudie Rowshan, Stephen Erickson, Raushan Kurmasheva, Peter Houghton, Beverly Teicher, Malcolm A. Smith. Pediatric Preclinical Testing Consortium (PPTC) of eribulin in osteosarcoma (OS) patient-derived xenograft (PDX) models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5872.

Heavy Drinkers and the Potential Impact of Minimum Unit Pricing-No Single or Simple Effect?

Aims

To explore the potential impact of a minimum unit price (MUP: 50 pence per UK unit) on the alcohol consumption of ill Scottish heavy drinkers.

Methods

Participants were 639 patients attending alcohol treatment services or admitted to hospital with an alcohol-related condition. From their reported expenditure on alcohol in their index week, and assuming this remained unchanged, we estimated the impact of a MUP (50 ppu) on future consumption. (Around 15% purchased from both the more expensive on-sale outlets (hotels, pubs, bars) and from off-sales (shops and supermarkets). For them we estimated the change in consumption that might follow MUP if (i) they continued this proportion of 'on-sales' purchasing or (ii) their reported expenditure was moved entirely to off-sale purchasing (to maintain consumption levels)).

Results

Around 69% of drinkers purchased exclusively off-sale alcohol at <50 ppu. Their drinking, post MUP, may reduce by a mean of 33%. For this group, from a population of very heavy, ill consumers, we were unable to show a differential effect across multiple deprivation quintiles. For other drinkers there might be no reduction, especially if after MUP there were many products priced close to 50 ppu. Moving away from on-sales purchases could support, for some, an increase in consumption.

Conclusions

While a proportion of our harmed, heavy drinkers might be able to mitigate the impact of MUP by changing purchasing habits, the majority are predicted to reduce purchasing. This analysis, focusing specifically on harmed drinkers, adds a unique dimension to the evidence base informing current pricing policy.

Short Summary

From drink purchasing data of heavy drinkers, we estimated the impact of legislating £0.50 minimum unit price. Over two thirds of drinkers, representing all multiple deprivation quintiles, were predicted to decrease alcohol purchasing; remainder, hypothetically, could maintain consumption. Our data address an important gap within the evidence base informing policy.

Allogeneic hematopoietic stem cell transplantation is associated with cure and durable remission of late-onset primary isolated central nervous system hemophagocytic lymphohistiocytosis

Primary isolated CNS presentation of HLH is exceedingly rare and typically associated with significant morbidity and mortality. We describe an adolescent patient with late-onset, primary isolated CNS HLH and a compound heterozygous PRF1 mutation (c50delT (p.L17 fs); c.1229G>C (p.R410P)), not previously reported with this phenotype. He was successfully treated with allogeneic HSCT following a reduced-intensity conditioning regimen, despite a high pre-HSCT comorbidity index. Two years after transplant, he is alive and in disease remission. While patients with systemic HLH and active CNS disease have relatively poorer outcomes, a high index of suspicion may aid with early diagnosis of primary isolated CNS HLH; prompt treatment with HSCT may be associated with improved cure and durable remission of this rare disease.

Detection of circulating tumor DNA in patients with osteosarcoma

Identification and quantification of somatic alterations in plasma-derived, circulating tumor DNA (ctDNA) is gaining traction as a non-invasive and cost effective method of disease monitoring in cancer patients, particularly to evaluate response to treatment and monitor for disease recurrence. To our knowledge, genetic analysis of ctDNA in osteosarcoma has not yet been studied. To determine whether somatic alterations can be detected in ctDNA and perhaps applied to patient management in this disease, we collected germline, tumor, and serial plasma samples from pediatric, adolescent, and young adult patients with osteosarcoma and used targeted Next Generation Sequencing (NGS) to identify somatic single nucleotide variants (SNV), insertions and deletions (INDELS), and structural variants (SV) in 7 genes commonly mutated in osteosarcoma. We demonstrate that patient-specific somatic alterations identified through comparison of tumor-germline pairs can be detected and quantified in cell-free DNA of osteosarcoma patients.

Pediatric oncologist willingness to offer germline TP53 testing in osteosarcoma

BACKGROUND

Li-Fraumeni syndrome (LFS) is a cancer predisposition syndrome caused by mutations in the tumor-suppressor gene TP53. Osteosarcoma is a sentinel cancer in LFS. Prior studies using Sanger sequencing platforms have demonstrated that 3% of individuals with osteosarcoma harbor a mutation in TP53. New data from next-generation sequencing have demonstrated that 3.8% of patients with osteosarcoma have a known pathogenic variant, and an additional 5.7% carry exonic variants of unknown significance in TP53.

METHODS

Pediatric oncologists were e-mailed an anonymous 18-question survey assessing their willingness to offer TP53 germline testing to a child with osteosarcoma with or without a family history, and they were evaluated for changes in their choices with the prior data and the new data.

RESULTS

One hundred seventy-seven pediatric oncologists (22%) responded to the survey. Respondents were more likely to offer TP53 testing to a patient with a positive family history (77.4% vs 12.4%; P < .0001). Significantly more providers responded that they would offer TP53 testing once they were provided with the new data (25.4% vs 12.4%; P = .0038). The proportion of providers who responded that they were unsure increased significantly when they were presented with the new data (25.4% vs 10.2%; P = .0002). Potential implications for other family members and the possibility that surveillance imaging would detect new malignancies at an earlier stage were important factors influencing a provider's decision to offer TP53 testing.

CONCLUSIONS

Recent data increase the proportion of providers willing to offer testing, and this suggests concern on the part of pediatric oncologists that variants of unknown significance may be disease-defining in rare cancers. Cancer 2018;124:1242-50. © 2018 American Cancer Society.

Provider views on the management of Ewing sarcoma of the spine and pelvis

BACKGROUND

Curative therapy for ES requires both chemotherapy and local control of primary tumor. There is no universally accepted standard approach to local control modalities. This survey was conducted to determine practice patterns and factors influencing the choice to offer various local control modalities to patients with ES of the spine and pelvis.

METHODS

The survey consisted of four scenarios involving a 15-year-old girl who presented with Ewing sarcoma of thoracic vertebra, sacrum, iliac wing, and acetabulum with or without neurologic compromise. The questionnaire was sent to oncologists, orthopedic surgeons, and radiation oncologists, asking their recommendations for local control modality.

RESULTS

Among 94 respondents, radiotherapy was most frequently chosen for sacral tumors (68.1%) and T10 vertebral tumors (46.2%) whereas surgery was preferred for iliac wing pelvic tumors (45.7%) and acetabular tumors (43.6%). Orthopedic surgeons were significantly more likely to offer surgery than radiation oncologists (OR 3.07, 95%CI 1.37-6.88, P = 0.007). Providers outside North America were more likely to offer combined surgery plus radiotherapy (OR 10.58, 95%CI 5.41-20.70, P < 0.001).

CONCLUSION

Considerable heterogeneity exists in local control modalities for Ewing sarcoma of the spine and pelvis. Specialty and location of practice may influence treatment recommendations.