Bhuvana A. Setty

Heterozygous M1V variant of ELA-2 gene mutation associated with G-CSF refractory severe congenital neutropenia†

Severe congenital neutropenia is an autosomal recessive disorder characterized by maturation arrest at the promyelocyte/myelocyte phase in the bone marrow, absolute neutrophil count <0.5 × 109/L and recurrent bacterial infections. Homozygous mutations of either HAX‐1 or ELA‐2 have been described. We report the case of a premature male infant with congenital neutropenia, associated with multiple infections, refractory to treatment with granulocyte colony stimulating factor who subsequently underwent matched sibling donor stem‐cell transplant. He was found to be heterozygous for the M1V variant of the ELA‐2 gene that we postulate to be causative for his severe neutropenia. Pediatr Blood Cancer 2011; 57: 514–515.

VIncristine, irinotecan, and temozolomide in children and adolescents with relapsed rhabdomyosarcoma

The combination of vincristine, irinotecan, and temozolomide (VIT) is often used to treat children and adolescents with relapsed rhabdomyosarcoma (RMS); however, the outcome of these patients has not been previously described.

Rhabdomyosarcoma of the Breast in Adolescent and Young Adult (AYA) Women.

Soft tissue sarcoma constitutes 8% of all tumors in adolescent and young adults (AYA), with rhabdomyosarcoma (RMS) accounting for 5.2% to 6.5% of the soft tissue sarcoma total within this group. AYAs have a higher propensity for metastasis and inferior outcomes. Metastases to the breast have been reported in ∼3% to 6% of RMS cases. A review of our hospital’s tumor registry identified cases of RMS diagnosed between January 1, 2004 and December 31, 2013. A total of 46 patients with RMS were identified, having a mean age of 12.5 years (range, 1 to 49 y). There were 26 males (57%) and 20 females (43%). Eighteen patients (39%) were AYAs, including 10 women. Four patients (8.7%) were identified with breast involvement, all of whom were AYA females. Treatment modalities included chemotherapy, surgical resection, and radiation. One patient is a long-term survivor. Although RMS is uncommon in AYAs, breast involvement occurs almost exclusively in AYA women and is associated with alveolar histology, metastatic disease, and poor outcomes. In total, 4/10 of all AYA females had breast involvement. Routine examination or imaging of the breasts in AYAs with RMS is not currently standard practice at diagnosis or follow-up, but this analysis suggests it should be considered in female AYA patients.

Hypoxic Proliferation of Osteosarcoma Cells Depends on Arginase II

Background/Aims: Despite significant advancements in the diagnosis and treatment of osteosarcoma, the overall survival has remained relatively unchanged for over two decades. Hypoxic conditions have been demonstrated in solid tumors and are associated with increased cell proliferation and angiogenesis. L-arginine metabolism by arginase produces L-ornithine, the precursor for polyamine and proline synthesis required for cellular proliferation. We hypothesized that hypoxia would increase cellular proliferation via arginase induction in human osteosarcoma cell lines. Methods: We utilized a variety of approaches to examine the role of arginase II in hypoxic (1% O2, 5% CO2) cellular proliferation. Results: Arginase II mRNA and protein levels were significantly increased in osteosarcoma cells exposed to hypoxia for 48 hours. There were twice as many viable cells following 48 hours of hypoxia than following 48 hours of normoxia (21% O2, 5% CO2). The addition of difluoromethylornithine (DFMO), a putative arginase inhibitor, prevented hypoxia-induced proliferation. Transfection of small interfering RNAs (siRNA) targeting arginase II resulted in knockdown of arginase II protein levels and prevented hypoxia-induced cellular proliferation. Conclusions: These data support our hypothesis that hypoxia increases proliferation of osteosarcoma cells in an arginase II-dependent manner. We speculate that arginase II may represent a therapeutic target in osteosarcoma.

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

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.

Chemotherapy Regimens for Patients with Newly Diagnosed Malignant Bone Tumors

The advent of chemotherapy brought dramatic improvements to the care of patients stricken with malignant bone tumors. Early experimentation with cytotoxic medications identified a number of agents with activity in both Ewing’s sarcoma and osteosarcoma. Survival rates in patients treated with these new agents improved five- to six-fold over the course of less than a decade. Therapies identified during the early years of chemotherapy continue to form the backbone upon which most modern regimens are built. Efforts to further improve outcomes have proved difficult. Modest, incremental gains have come only through experimentation involving large populations of patients made possible through the emergence of international cooperative groups. Advances in supportive care have facilitated the gradual intensification of treatment regimens both in terms of dose intensity and interval compression. Patients with refractory or metastatic disease continue to fare poorly. New approaches to the treatment of these patients are desperately needed.

Abstract CT145: A phase I window, dose escalating and safety trial of Metformin in combination with induction chemotherapy (VPLD)in relapsed/refractory acute lymphoblastic leukemia: NCT01324180

Background: Relapsed Acute Lymphoblastic Leukemia (ALL) remains a major cause of cancer-related deaths in children. We identified the AMP activated protein kinase (AMPK) as a potential target for ALL therapy due to its regulatory effects on the unfolded protein response (UPR), leading to increased vulnerability of ALL cells to endoplasmic reticulum (ER) stress inducers. In vitro, metformin leads to ALL cell death via AMPK-mediated inhibition of the UPR. Methods: Metformin was administered twice daily continuously on a 28 day cycle in addition to the Vincristine, Dexamethasone, PEG-Asparaginase and Doxorubicin (VPLD) systemic regimen and CNS-directed therapy in pediatric patients with relapsed/refractory ALL. Metformin doses were increased in a standard 3+3 phase I design with three dose levels evaluated, 666, 1,000 and 1,333 mg/m2/day. Pharmacokinetic (PK) and pharmacodynamic (PD) evaluation of the AMPK and ER stress/UPR pathways were ascertained on days 1 and 7, and treatment response was assessed on day 29. Results: Fourteen patients were enrolled, 11 evaluable. DL3 was the maximum administered dose with 2 related DLT’s of diarrhea and acidosis. A single DLT of hypoglycemia and acidosis during an episode of sepsis was observed in DL2. Infectious SAE’s occurred in 7 patients. Two patients had posterior reversible encephalopathy syndrome; both died of disease progression within 30 days of coming off study. A single patient had stable disease, 2 had a partial response, and 3 achieved a complete response. PK studies demonstrated levels within the therapeutic range for patients with diabetes, and PD evaluation showed induction of ER stress and inhibition of the UPR. Conclusions: This trial has been completed. We found induction of ER stress with inhibition of UPR consistent with that observed in vitro leading to metformin-induced apoptosis. The chemotherapeutic backbone was tolerable and the combination with metformin yielded responses in a heavily pretreated population. Toxicities attributable to metformin occurred in all dose levels, but DLT’s were only observed in dose levels above the standard dosing for diabetes. Clinical trial information: NCT01324180 Citation Format: Matteo Trucco, Julio Barredo, John Goldberg, Gregory Hale, Jonathan Gill, Bhuvana Setty, Tiffany Smith, Jae Lee, Damon Reed. A phase I window, dose escalating and safety trial of Metformin in combination with induction chemotherapy (VPLD)in relapsed/refractory acute lymphoblastic leukemia: NCT01324180 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT145. doi:10.1158/1538-7445.AM2017-CT145

Histological Response and Biological Markers

The optimization of treatment strategies for patients with bony tumors has proven to be elusive. Though patients with localized disease have achieved increased survival rates with the most recent therapeutic revolutions of dose escalation and interval compression, prognosis continues to remain significantly poor for those patients with metastatic disease. Stratification of bone tumor patients into risk categories is one method to target more intensified treatment regimens for patients with historically worse outcomes, while sparing patients with lower-risk disease from toxicities associated with highly aggressive therapies. Strategies to risk stratify these patients must involve incorporation of their tumor biology, including the presence or absence of significant biological markers, and their interval responses to treatment. The prognostic implications of biological markers and the histological response to neoadjuvant chemotherapy for bone tumors have been extensively studied. As further designations of risk groups for patients evolve, it has become apparent that these are crucial factors to consider.

Post-therapy Surveillance of Bone Tumors

Survival of patients with pediatric bone tumors have slowly improved, with more than half with localized disease staying alive 5 years after primary diagnosis. Post chemotherapy surveillance detects disease that can be managed by therapeutic options. The WHO and RECIST criteria utilize tumor response criteria as an endpoint for many clinical trials. International cooperative groups such as the Children’s Oncology Group Bone tumor committee have put forth consensus guidelines for surveillance. This chapter aims to discuss the rationale, utility and standard recommendations for surveillance post chemotherapy for those with pediatric bone tumors.