Capillary malformations

Capillary malformation (CM), or port wine birthmark, is a cutaneous congenital vascular anomaly that occurs in 0.1%-2% of newborns. Patients with a CM localized on the forehead have an increased risk of developing a neurocutaneous disorder called encephalotrigeminal angiomatosis or Sturge-Weber syndrome (SWS), with complications including seizure, developmental delay, glaucoma, and vision loss. In 2013, a groundbreaking study revealed causative activating somatic mutations in the gene (GNAQ) encoding guanine nucleotide-binding protein Q subunit α (Gαq) in CM and SWS patient tissues. In this Review, we discuss the disease phenotype, the causative GNAQ mutations, and their cellular origin. We also present the endothelial Gαq-related signaling pathways, the current animal models to study CM and its complications, and future options for therapeutic treatment. Further work remains to fully elucidate the cellular and molecular mechanisms underlying the formation and maintenance of the abnormal vessels.

Brain AVM compactness score in children with hereditary hemorrhagic telangiectasia

OBJECTIVE

The brain arteriovenous malformation (BAVM) nidus compactness score (CS), determined on angiography, predicts BAVM recurrence after surgical resection among children with sporadic BAVMs. We measured the angiographic CS for BAVMs among children with hereditary hemorrhagic telangiectasia (HHT) to determine CS characteristics in this population.

METHODS

A pediatric interventional neuroradiologist reviewed angiograms to determine the CS of BAVMs in children with HHT recruited to the BVMC. CS is based on overall nidus and perinidal anomalous vessel compactness. CS categories included 1 = diffuse nidus, 2 = intermediate nidus, and 3 = compact nidus.

RESULTS

Forty-eight of 78 children (61.5%) with HHT and brain vascular malformations had a conventional angiogram; 47 (97.9%) angiograms were available. Fifty-four BAVMs were identified in 40 of these 47 children (85.1%). Of 54 BAVMs in children with HHT, CS was 1 in 7 (13%), 2 in 29 (53.7%), and 3 in 18 BAVMs (33.3%) compared with CS of 1 in six (26.1%), 2 in 15 (65.2%), and 3 in 2 BAVMs (8.7%) among 23 previously reported children with sporadic BAVMs, p = 0.045 (Fisher's exact). Seven children with HHT had intracranial hemorrhage: 4 had CS = 3, 1 had CS = 2, and 2 had CS = 1.

CONCLUSIONS

A range of CSs exists across HHT BAVMs, suggesting it may be an angiographic measure of interest for future studies of BAVM recurrence and hemorrhage risk. Children with HHT may have more compact niduses compared to children with sporadic BAVMs. Additional research should determine whether CS affects hemorrhage risk or post-surgical recurrence risk in HHT-associated BAVMs, which could be used to direct BAVM treatment.

Practice Variations in Managing Infantile Hemangiomas

Infantile hemangioma (IH) is the most common benign tumor of infancy. For children with IH who require treatment, propranolol and other beta blockers have been shown to be safe and effective. Although consensus guidelines for managing IH have been published, anecdotal experience suggests that there remain variations in management. This study was performed to document these variations amongst providers and to identify areas for future research. We conducted an Internet-based survey of clinicians who treat patients with IH. Hypothetical cases and management scenarios were presented. Twenty-nine respondents participated in the survey. Most respondents use generic propranolol in infants with growing IH of the head and neck, with a goal dose of 2 mg/kg/d, until ~1 year of age. A variety of management strategies were documented including which patients should be treated, optimal dose and duration of therapy, how patients should be monitored, which patients should get additional workup, how propranolol should best be discontinued, and how often to see patients in follow-up. This study demonstrates wide practice variations in managing patients with IH. Further research is indicated to address these variations and develop additional/updated evidence-based guidelines.

Barriers to Genetic Testing in Vascular Malformations

Importance

Vascular malformations (VMs) are rare disorders of vasculogenesis associated with substantial morbidity. Improved understanding of their genetic basis is increasingly guiding management, but logistical barriers to obtaining genetic testing in patients with VM may constrain treatment options.

Objectives

To examine the institutional mechanisms for and obstacles to obtaining genetic testing for VM.

Design, Setting, and Participants

This survey study invited members of the Pediatric Hematology-Oncology Vascular Anomalies Interest Group, representing 81 vascular anomaly centers (VACs) serving individuals up to 18 years of age, to complete an electronic survey. Respondents were mostly pediatric hematologists-oncologists (PHOs) but included geneticists, genetic counselors, clinic administrators, and nurse practitioners. Responses that were received between March 1 and September 30, 2022, were analyzed with descriptive methods. Requirements for genetic testing by several genetics laboratories were also reviewed. Results were stratified by size of the VAC.

Main Outcomes and Measures

Vascular anomaly center and associated clinician characteristics and practice patterns for ordering and obtaining insurance approval for genetic testing for VMs were collected.

Results

Responses were received from 55 of 81 clinicians, for a response rate of 67.9%. Most respondents were PHOs (50 [90.9%]). Most respondents (32 of 55 respondents [58.2%]) replied that they order genetic testing on 5 to 50 patients per year and reported a genetic testing volume increase of 2- to 10-fold over the past 3 years (38 of 53 respondents [71.7%]). Most testing was ordered by PHOs (35 of 53 respondents [66.0%]), followed by geneticists (28 [52.8%]) and genetic counselors (24 [45.3%]). In-house clinical testing was more common at large and medium-sized VACs. Small VACs were more likely to use oncology-based platforms, which potentially miss low-frequency allelic variants in VM. Logistics and barriers varied by size of the VAC. Obtaining prior authorization was the duty shared among PHOs, nurses, and administrative staff, but the burden of insurance denials and appeals were on PHOs (35 of 53 respondents [66.0%]). Lack of administrative support; unclear institutional, insurance, and laboratory requirements; and lack of clinician education were barriers to genetic testing at VACs of all sizes. The effort to obtain genetic testing for patients with VM, compared with patients with cancer, was perceived as excessive, despite genetic testing being considered standard of care for this population.

Conclusions and Relevance

Results of this survey study showed the barriers to genetic testing for VM across VACs, described differences between VACs based on size, and proposed multiple interventions to support clinicians ordering genetic testing for VM. The results and recommendations should have broader application to clinicians caring for patients for whom molecular diagnosis is important to medical management.

Kaposiform lymphangiomatosis: Diagnosis, pathogenesis, and treatment

Kaposiform lymphangiomatosis (KLA) is a life-threatening rare disease that can cause substantial morbidity, mortality, and social burdens for patients and their families. Diagnosis often occurs long after initial symptoms, and there are few centers in the world with the expertise to diagnose and care for patients with the disease. KLA is a lymphatic anomaly and significant advancements have been made in understanding its pathogenesis and etiology since its first description in 2014. This review provides multidisciplinary, comprehensive, and state-of-the-art information on KLA patient presentation, diagnostic imaging, pathology, organ involvement, genetics, and pathogenesis. Finally, we describe current therapeutic approaches, important areas for research, and challenges faced by patients and their families. Further insights into the pathogenesis of KLA may advance our understanding of other vascular anomalies given that similar signaling pathways may be involved.

Genetic testing in the evaluation of individuals with clinical diagnosis of atypical Sturge-Weber syndrome

Sturge-Weber Syndrome (SWS) is a rare vascular malformation disorder characterized by abnormal blood vessels in the brain, skin, and eye. SWS is most commonly caused by a somatic mosaic GNAQ-p.Arg183Gln variant. In this series, 12 patients presented for clinical evaluation of SWS but were noted to have atypical features, and therefore germline and/or somatic genetic testing was performed. Atypical features included extensive capillary malformation on the body as well as the face, frontal bossing, macrocephaly, telangiectasia, overgrowth of extremities, absence of neurologic signs and symptoms, and family history of vascular malformations. Five patients had a somatic GNAQ or GNA11 pathogenic variant, one patient had a somatic mosaic likely-pathogenic variant in PIK3CA, and another one had a somatic mosaic deletion that disrupted PTPRD. The other five patients had germline variants in RASA1, EPHB4, or KIT. Our findings suggest that patients presenting for SWS evaluation who have atypical clinical characteristics may have pathogenic germline or somatic variants in genes other than GNAQ or GNA11. Broad germline and somatic genetic testing in these patients with atypical findings may have implications for medical care, prognosis, and trial eligibility.

How we approach genetics in the diagnosis and management of vascular anomalies

Vascular anomalies are a heterogeneous group of disorders that are currently classified based on their clinical and histological characteristics. Over the past decade, there have been significant advances in molecular genetics that have led to identification of genetic alterations associated with vascular tumors, vascular malformations, and syndromes. Here, we describe known genetic alterations in vascular anomalies, discuss when and how to test, and examine how identification of causative genetic mutations provides for better management of these disorders through improved understanding of their pathogenesis and increasing use of targeted therapeutic agents in order to achieve better outcomes for our patients.

Hereditary hemorrhagic telangiectasia (HHT): a practical guide to management

Hereditary hemorrhagic telangiectasia (HHT), the second most common inherited bleeding disorder, is associated with the development of malformed blood vessels. Abnormal blood vessels may be small and cutaneous or mucosal (telangiectasia), with frequent complications of bleeding, or large and visceral (arteriovenous malformations [AVMs]), with additional risks that can lead to significant morbidity and even mortality. HHT can present in many different ways and can be difficult to recognize, particularly in younger patients in the absence of a known family history of disease or epistaxis, its most common manifestation. HHT is commonly diagnosed using the established Curaçao clinical criteria, which include (1) family history, (2) recurrent epistaxis, (3) telangiectasia, and (4) visceral AVMs. Fulfillment of 3 or more criteria provides a definite diagnosis of HHT, whereas 2 criteria constitute a possible diagnosis of HHT. However, these criteria are insufficient in children to rule out disease due to the age-dependent development of some of these criteria. Genetic testing, when positive, can provide definitive diagnosis of HHT in all age groups. Clinical course is often complicated by significant epistaxis and/or gastrointestinal bleeding, leading to anemia in half of adult patients with HHT. The management paradigm has recently shifted from surgical approaches to medical treatments aimed at control of chronic bleeding, such as antifibrinolytic and antiangiogenic agents, combined with aggressive iron replacement with intravenous iron. Guidelines for management of HHT, including screening and treatment, were determined by expert consensus and originally published in 2009 with updates and new guidelines in 2020.

A review of mechanisms of disease across PIK3CA-related disorders with vascular manifestations

BACKGROUND

PIK3CA-related disorders include vascular malformations and overgrowth of various tissues that are caused by postzygotic, somatic variants in the gene encoding phosphatidylinositol-3-kinase (PI3K) catalytic subunit alpha. These mutations result in activation of the PI3K/AKT/mTOR signaling pathway. The goals of this review are to provide education on the underlying mechanism of disease for this group of rare conditions and to summarize recent advancements in the understanding of, as well as current and emerging treatment options for PIK3CA-related disorders.

MAIN BODY

PIK3CA-related disorders include PIK3CA-related overgrowth spectrum (PROS), PIK3CA-related vascular malformations, and PIK3CA-related nonvascular lesions. Somatic activating mutations (predominantly in hotspots in the helical and kinase domains of PIK3CA, but also in other domains), lead to hyperactivation of the PI3K signaling pathway, which results in abnormal tissue growth. Diagnosis is complicated by the variability and overlap in phenotypes associated with PIK3CA-related disorders and should be performed by clinicians with the required expertise along with coordinated care from a multidisciplinary team. Although tissue mosaicism presents challenges for confirmation of PIK3CA mutations, next-generation sequencing and tissue selection have improved detection. Clinical improvement, radiological response, and patient-reported outcomes are typically used to assess treatment response in clinical studies of patients with PIK3CA-related disorders, but objective assessment of treatment response is difficult using imaging (due to the heterogeneous nature of these disorders, superimposed upon patient growth and development). Despite their limitations, patient-reported outcome tools may be best suited to gauge patient improvement. New therapeutic options are needed to provide an alternative or supplement to standard approaches such as surgery and sclerotherapy. Currently, there are no systemic agents that have regulatory approval for these disorders, but the mTOR inhibitor sirolimus has been used for several years in clinical trials and off label to address symptoms. There are also other agents under investigation for PIK3CA-related disorders that act as inhibitors to target different components of the PI3K signaling pathway including AKT (miransertib) and PI3K alpha (alpelisib).

CONCLUSION

Management of patients with PIK3CA-related disorders requires a multidisciplinary approach. Further results from ongoing clinical studies of agents targeting the PI3K pathway are highly anticipated.

Multicenter Research Data of Epilepsy Management in Patients With Sturge-Weber Syndrome

BACKGROUND

Epilepsy in typical Sturge-Weber syndrome (SWS) is common, and many questions remain regarding the treatment outcomes. We analyzed a large multicenter database with focus on neurological drug treatment in different demographic and SWS characteristic groups.

METHODS

A total of 268 patients with brain involvement and a history of seizures were selected from a research data registry generated from a multicenter cross-sectional questionnaire. We examined associations between medication use and binary variables such as sex, ethnicity, and brain, skin, and eye involvement laterality. We analyzed group differences in mean number of antiseizure medications and age at diagnosis, enrollment, and seizure onset and examined differences in median SWS neurological scores in groups of interest.

RESULTS

The most frequently used medications were levetiracetam (48.1%), low-dose aspirin (44.8%), oxcarbazepine (39.9%), and phenobarbital (14.9%). Lamotrigine was more frequently used in adults than in children (P = 0.001). History of neurosurgery was associated with no current antiseizure medication use (P = 0.001), whereas bilateral brain involvement and family history of seizures were associated with using a higher number of antiseizure medications (P = 0.002, P = 0.027, respectively). Subjects with bilateral brain involvement and early seizure onset were associated with using a higher number of antiseizure medications (P = 0.002) and phenobarbital use (0.003).

CONCLUSIONS

Levetiracetam, low-dose aspirin, and oxcarbazepine were the most frequently used medications. More severely affected patients were frequently on a greater number of antiseizure medications. Surgery for epilepsy was associated with the ability to discontinue antiseizure medication. Longitudinal studies are needed to further investigate medication use in patients with SWS.

EPIK-P2: A prospective phase 2, double-blind, randomized, placebo-controlled study of alpelisib in pediatric and adult patients (Pts) with PIK3CA-related overgrowth spectrum (PROS)

TPS3160

Background: Somatic gain-of-function mutations in the PIK3CA gene, encoding the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) catalytic α subunit (p110α), can result in PI3K pathway hyperactivation. PROS is an umbrella term for rare, phenotypically varied, but overlapping features driven by PIK3CA mutations. Disease onset is often congenital or in early childhood; presentation ranges widely from localized overgrowth to pleiotropic, severe overgrowth. Complications depend on anatomical site and extent of overgrowth. Management of PROS currently involves symptomatic treatment of its manifestations; an unmet need exists for targeted, systemic therapies. Alpelisib, a PI3Kα inhibitor, has demonstrated encouraging clinical observations and a promising safety profile; after 6 mo of treatment, pediatric and adult pts with PROS experienced improvements in symptoms without requiring surgery. A low rate of side effects was observed (Venot Q, et al. Nature. 2018;558:540-6). Methods: EPIK-P2 is a prospective, phase 2, multicenter study with an upfront 16-week, randomized, double-blind, placebo-controlled period. Key eligibility criteria include male or female ≥6 yr of age with PROS and symptomatic and/or progressive overgrowth; ≥1 PROS-related measurable lesion confirmed by a Blinded Independent Review Committee (BIRC) and documented somatic PIK3CA mutation. Pts with isolated cases of macrodactyly, epidermal nevus/nevi, or macrocephaly in absence of other PROS-related lesions; previous treatment with PI3K inhibitor(s); or debulking surgery within 3 mo are not eligible. Approximately 138 pts will be enrolled into 2 groups comprising adult (age ≥18 yr) and pediatric (ages 6-17 yr) pts. Pts will be randomized 2:1 to daily oral alpelisib or matching placebo; adults will receive 125 mg and pediatric pts 50 mg. After 16 weeks, pts randomized to placebo will switch to alpelisib in a blinded fashion; pts receiving alpelisib will continue alpelisib. Treatment will continue for up to 5 yr. The primary objective is to demonstrate the efficacy of alpelisib by the proportion of pts randomized to alpelisib with a response at Week 24 in each group. Response is defined as ≥20% volume reduction in the symptomatic target lesion(s) per BIRC. The key secondary objective is to demonstrate efficacy of alpelisib vs placebo based on the proportion of pts in each group with response at Week 16. Other secondary outcomes include safety and tolerability, duration of response, overall clinical response rates, changes in symptoms and comorbidities, patient-reported outcomes, pharmacokinetics, and healthcare utilization. An exploratory group of pts (n = 12) ages 2-5 yr will be later enrolled once a starting dose of alpelisib is confirmed in these pts. Enrollment of 150 pts is anticipated. Clinical trial information: NCT04589650.

Sirolimus Treatment in Sturge-Weber Syndrome

BACKGROUND

Sturge-Weber syndrome is a rare neurovascular disorder associated with capillary malformation, seizures, cognitive impairments, and stroke-like episodes (SLEs), arising from a somatic activating mutation in GNAQ. Studies suggest this mutation may cause hyperactivation of the mammalian target of rapamycin pathway. Sirolimus is an mammalian target of rapamycin inhibitor studied in other vascular anomalies and a potentially promising therapy in Sturge-Weber syndrome.

METHODS

Ten patients with Sturge-Weber syndrome brain involvement and cognitive impairments were enrolled. Oral sirolimus was taken for six months (maximum dose: 2 mg/day, target trough level: 4-6 ng/mL). Neuropsychological testing, electroencephalography, and port-wine score were performed at baseline and after six months on sirolimus. Neuroquality of life, adverse events, and Sturge-Weber Syndrome Neurological Score (neuroscore) were recorded at each visit.

RESULTS

Sirolimus was generally well tolerated; one subject withdrew early. Adverse events considered related to sirolimus were mostly (15/16) grade 1. A significant increase in processing speed was seen in the overall group (P = 0.031); five of nine patients with available data demonstrated statistically rare improvement in processing speed. Improvements were seen in the neuroquality of life subscales measuring anger (P = 0.011), cognitive function (P = 0.015), and depression (P = 0.046). Three subjects experiencing SLEs before and during the study reported shortened recovery times while on sirolimus.

CONCLUSIONS

Sirolimus was well tolerated in individuals with Sturge-Weber syndrome and may be beneficial for cognitive impairments, especially in patients with impaired processing speed or a history of SLE. A future, randomized, placebo-controlled trial of sirolimus in patients with Sturge-Weber syndrome is needed to further understand these potentially beneficial effects.

Retrospective study of hematologic complications in patients with slow-flow vascular malformations undergoing sclerotherapy

BACKGROUND

Slow-flow vascular malformations (SFVM) are associated with localized intravascular coagulopathy (LIC), which is characterized by elevated D-dimer and, when severe, hypofibrinogenemia. LIC results in intralesional clotting and hemorrhage and increases risk for significant thrombotic and bleeding complications. Sclerotherapy has been a suggested potential trigger for LIC worsening to disseminated intravascular coagulopathy. Hematologic complications of sclerotherapy in SFVM, along with low-molecular-weight heparin (LMWH) used to prevent worsening LIC, are largely unstudied.

PROCEDURE

Medical records of patients with SFVM and LIC who underwent sclerotherapy at Cincinnati Children's Hospital Medical Center from July 2008 to December 2016 were reviewed for periprocedural hematologic complications. LMWH dose, frequency, and course length were evaluated.

RESULTS

Fifty-nine patients with SFVM and LIC underwent 281 sclerotherapy procedures, of which 86% were in children. Eighty-five percent of patients received periprocedural LMWH, although at various doses and course lengths. No thrombotic complications occurred in children. One adult on LMWH developed pulmonary emboli after sclerotherapy. No major bleeding complications occurred postoperatively. In four patients, fibrinogen dropped below 100 mg/dL post-sclerotherapy, requiring cryoprecipitate. One patient required packed red blood cell (RBC) transfusion for sclerotherapy-induced hemolysis. No intraoperative bleeding or thrombotic events occurred.

CONCLUSION

LMWH use, at subtherapeutic dosing, was common in this patient population and did not appear to increase risk of significant bleeding before, during, or after sclerotherapy. In children with SFVM, bleeding and thrombotic complications after sclerotherapy appear rare. Although safe, prospective studies are needed to evaluate the efficacy of LMWH to prevent worsening coagulopathy with procedures.

Overgrowth syndromes and new therapies

Overgrowth syndromes represent a diverse group of disorders with overlapping features. Interdisciplinary management by a team of experts in vascular anomalies is crucial for establishing the correct diagnosis and optimizing outcomes for these patients. Unique management considerations include increased risk for thrombosis and in some cases, cancer. In recent years, research has demonstrated that these disorders are primarily caused by somatic mutations in growth pathways, particularly the PI3K-mTOR pathway. This improved understanding had led to promising new therapies for this group of patients.

Constitutively active PIK3CA mutations are expressed by lymphatic and vascular endothelial cells in capillary lymphatic venous malformation

Capillary lymphatic venous malformations (CLVM) are complex vascular anomalies characterized by aberrant and enlarged lymphatic and blood vessels. CLVM appear during fetal development and enlarge after birth, causing life-long complications such as coagulopathy, pulmonary embolism, chronic pain, and disfigurement. Treatment includes surgical debulking, amputation, and recurrent sclerotherapy. Somatic, mosaic mutations in the 110-kD catalytic α-subunit of phosphoinositide-3-kinase (PIK3CA) gene have been previously identified in affected tissues from CLVM patients; however, the cell population harboring the mutation is still unknown. In this study, we hypothesized that endothelial cells (EC) carry the PIK3CA mutations and play a major role in the cellular origin of CLVM. We isolated EC from the lesions of seven patients with CLVM and identified PIK3CA hotspot mutations. The CLVM EC exhibited constitutive phosphorylation of the PI3K effector AKT as well as hyperproliferation and increased resistance to cell death compared to normal EC. Inhibitors of PIK3CA (BYL719) and AKT (ARQ092) attenuated the proliferation of CLVM EC in a dose-dependent manner. A xenograft model of CLVM was developed by injecting patient-derived EC into the flanks of immunocompromised mice. CLVM EC formed lesions with enlarged lymphatic and vascular channels, recapitulating the patient histology. EC subpopulations were further obtained by both immunomagnetic separation into lymphatic EC (LEC) and vascular EC (VEC) and generation of clonal populations. By sequencing these subpopulations, we determined that both LEC and VEC from the same patient express the PIK3CA mutation, exhibit increased AKT activation and can form lymphatic or vascular lesions in mouse.

Sirolimus for the treatment of juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibroma (JNA) is a pathologically benign yet locally aggressive and destructive tumor that develops in the choana and nasopharynx. Historical treatment of JNA has included embolization, surgical resection, and radiation. Here, we describe three patients who received therapy with the mTOR inhibitor sirolimus with improvement in clinical symptoms, imaging, and overall well-being.

Single-stage embolization with n-butyl cyanoacrylate and surgical resection of venous malformations

PURPOSE

Sclerotherapy or surgical resection is options for symptomatic venous malformations (VM). Sclerotherapy may require repetitive intervention and resection is often avoided due to operative morbidity. The purpose of this study was to report use of single-stage n-butyl cyanoacrylate glue embolization and surgical resection of focal VM.

METHODS

A review of patients with focal VM who underwent glue embolization followed by resection at a single tertiary care vascular malformations center was performed. All embolizations were performed with ultrasound and fluoroscopy under the same anesthetic as resection. Patient characteristics and outcomes were evaluated.

RESULTS

Fifteen procedures were performed in 12 patients with a total of 20 VM addressed, as several patients had multiple VM. Mean age was 16 ± 9 years. Malformation locations included scalp, hip, gluteal, labial, toe, finger, face, lip, chest, and foot and size ranged from 1.0 to 10.5 cm. Median (range) of prior sclerotherapy treatments was 3 (0-5) and three patients previously underwent surgical resection. Median blood loss was zero (0-10) mL. Surgical complications occurred after five procedures (33%) including superficial wound dehiscence and cellulitis. No complications required readmission or reoperation. At a median follow up of 195 (103-266) days, no patients have required additional treatment.

CONCLUSION

Glue embolization and resection of focal VM of variable size and location appears to have durable results and low surgical morbidity. This single-stage procedure, often performed as an outpatient, may be utilized as upfront treatment for symptomatic malformations or for VM refractory to other treatments.

Quality of Life in Children With Sturge-Weber Syndrome

AIM

We assessed the utilization of the National Institutes of Health Quality of Life in Neurological Disorders (Neuro-QoL) in pediatric patients with Sturge-Weber syndrome, a rare neurovascular disorder which frequently results in seizures, brain atrophy, calcification, and a range of neurological impairments.

METHODS

Subjects were seen clinically and consented for research. All 22 patients filled out the Pediatric Neuro-QoL. The Neuro-QoL subscores were converted to T-scores to compare with the referenced control population. Twenty-one participants also filled out the Brain Vascular Malformation Consortium Database Questionnaire containing data pertaining to Sturge-Weber syndrome-related medical history, medications, comorbidities, and family history. All data were analyzed with a significance threshold of P < 0.05.

RESULTS

Cognitive function quality of life was significantly lower (P < 0.001) in pediatric patients with Sturge-Weber syndrome compared with referenced control subjects. Male gender (P = 0.02) was associated with lower cognitive function Neuro-QoL. The extent of skin (R = -0.46, P = 0.04), total eyelid port-wine birthmark (R = -0.56, P = 0.007), eye (R = -0.58, P = 0.005), and total Sturge-Weber syndrome involvement (R = -0.63, P = 0.002) were negatively correlated with cognitive function Neuro-QoL. A younger age at seizure onset was associated with lower cognitive function Neuro-QoL (hazard ratio = 0.90, P = 0.004) even after controlling for extent of brain, skin, or eye involvement. Antidepressant use was associated with lower cognitive function Neuro-QoL (P = 0.005), and cognitive function Neuro-QoL was negatively correlated with depression Neuro-QoL; however, after adjusting for depression this relationship was no longer significant.

CONCLUSIONS

The results suggest targeting cognitive function Neuro-QoL in treatment trials and reiterate the prognostic value of early seizure onset. In addition, sex-related differences were noted, which should be further studied.

Signaling pathways and inhibitors of cells from patients with kaposiform lymphangiomatosis

BACKGROUND

Kaposiform lymphangiomatosis (KLA) is a rare lymphatic anomaly with significant morbidity and mortality. KLA is characterized by diffuse multifocal lesions comprised of focal areas of "kaposiform" spindled cells accompanying malformed lymphatic channels. The goal of this study was to identify activated signaling pathways in cells isolated from three KLA patients for the purpose of testing new therapies.

PROCEDURE

Cells were obtained from the lungs of one patient isolated at autopsy and the spleen of two patients removed in surgery due to disease complications. A protein kinase array was performed on the KLA cell lysates and normal lymphatic endothelial cells.

RESULTS

Higher activation of key signaling pathways in the KLA cells, including PRAS40, AKT1/2/3, and ERK-1/2, was identified by protein kinase array and confirmed by Western blot analysis. This indicated a role for highly activated PI3K-AKT and MAPK-ERK-1/2 signaling pathways in KLA cells. Cell proliferation studies assessed PI3K inhibitors (LY294002; BYL719), AKT inhibitor ARQ092, mTOR inhibitor rapamycin, and MAPK inhibitor U0126. These studies demonstrated that PI3K-AKT-mTOR and MAPK signaling are important mediators of KLA cell proliferation. BYL719 and rapamycin were more effective at inhibiting KLA cell proliferation than U0126.

CONCLUSIONS

Our studies using cells from KLA patient lesions demonstrate that these cells are highly proliferative and the PI3K-AKT-mTOR and MAPK pathways are promising therapeutic targets. Development and clinical trials of PI3K, AKT, and MAPK inhibitors for cancer treatment and the data in this study lend support for early clinical trials assessing the efficacy of these inhibitors in KLA patients.

Efficacy of systemic sirolimus in the treatment of generalized lymphatic anomaly and Gorham-Stout disease

BACKGROUND

Generalized lymphatic anomaly (GLA) and Gorham-Stout disease (GSD) are rare complicated lymphatic malformations that occur in multiple body sites and are associated with significant morbidity and mortality. Treatment options have been limited, and conventional medical therapies have been generally ineffective. Emerging data suggest a role for sirolimus as a treatment option for complex lymphatic anomalies.

PROCEDURE

Disease response was evaluated by radiologic imaging, quality of life (QOL), and clinical status assessments in children and young adults with GLA and GSD from a multicenter systematic retrospective review of patients treated with oral sirolimus and the prospective phase 2 clinical trial assessing the efficacy and safety of sirolimus in complicated vascular anomalies (NCT00975819). Sirolimus dosing regimens and toxicities were also assessed.

RESULTS

Eighteen children and young adults with GLA (n = 13) or GSD (n = 5) received oral sirolimus. Fifteen patients (83%) had improvement in one or more aspects of their disease (QOL 78%, clinical status 72%, imaging 28%). No patients with bone involvement had progression of bone disease, and the majority had symptom or functional improvement on sirolimus. Improvement of pleural and pericardial effusion(s) occurred in 72% and 50% of affected patients; no effusions worsened on treatment.

CONCLUSIONS

Sirolimus appears effective at stabilizing or reducing signs/symptoms of disease in patients with GLA and GSD. Functional impairment and/or QOL improved in the majority of individuals with GLA and GSD with sirolimus treatment.

Surgical resection of infantile hemangiomas following medical treatment with propranolol versus corticosteroids

PURPOSE

There has been a paradigm shift from corticosteroid to propranolol treatment for infantile hemangiomas (IHs), with surgical resection reserved for complicated or persistent IHs. The purpose of this study was to determine if propranolol treatment was associated with decreased utilization of surgical resection compared to corticosteroids.

METHODS

A single center retrospective chart review of all corticosteroid or propranolol treated IHs between 2005 and 2014 was performed. Demographic and clinical data were collected. Both univariate and multivariate analyses were performed with the primary outcome of requiring surgical intervention.

RESULTS

Of 652 patients with IH, 52 were treated with oral corticosteroids and 195 with propranolol only. Surgical intervention was required in 14 (27%) of steroid patients vs 18 (9%) of propranolol patients (p < .001). On multivariable analysis patients treated with steroids had 3.3 the odds of requiring surgery when compared to propranolol patients (p = .001). Prematurity (<37 weeks) was also associated with increased odds of surgery (OR = 2.8, p = .003).

CONCLUSION

Patients treated with propranolol required significantly fewer surgical interventions than those treated with corticosteroids suggesting a more efficacious treatment paradigm. Prematurity increases the need for surgical intervention regardless of the modality of medical treatment.

LEVEL OF EVIDENCE

Level III, treatment study.

Developmental pharmacokinetics of sirolimus: Implications for precision dosing in neonates and infants with complicated vascular anomalies

BACKGROUND

Sirolimus has recently been shown to be efficacious and tolerable in pediatric patients with complicated vascular anomalies. Nevertheless, dosing information remains very limited especially for neonates and infants. The purpose of this study was to develop an age-appropriate sirolimus starting dosing regimen based on the developmental changes in drug elimination capacity using data collected in neonates and infants.

PROCEDURE

A recently developed sirolimus maturation model [Emoto et al. CPT Pharmacometrics Syst Pharmacol, 2016] was used to simulate clearance estimates using realistic age and weight covariates for age cohorts aged 0-24 months. Next, predose concentrations at steady state were generated for each age cohort of neonates and infants. Dose requirements to attain predefined target trough concentration ranges (10-15 and 5-10 ng/ml) were simulated across the different age groups. Starting doses were chosen to maximize the likelihood of achieving sirolimus-targeted concentrations.

RESULTS

The trajectory of simulated sirolimus clearances increased with age and was in agreement with the previous findings in the Phase 2 study. The proposed dosing regimens covered eight age cohorts and resulted in target attainment of more than 75-95% across selected regimens.

CONCLUSIONS

This study identified age-appropriate sirolimus dosing regimens for neonates and infants. The algorithm in combination with therapeutic drug management will facilitate sirolimus precision dosing in young children with vascular anomalies. A prospective evaluation is being planned.

Model-based precision dosing of sirolimus in pediatric patients with vascular anomalies

Sirolimus is the first drug to show efficacy in the treatment of patients with complicated vascular anomalies. The current study expands on the evolution of a PK model-based strategy for the precision dosing of sirolimus as part of prospective concentration controlled clinical trials in pediatric patients with vascular anomalies. Twelve month follow up data collected from 52 pediatric patients participating in the Phase 2 clinical trial were analyzed. Target attainment across the age range of 3weeks to 18years after 2-3months of therapy was 94% (49 out of 52 patients). The mean sirolimus dose to achieve the target of ~10ng/mL for patients older than 2years was 1.8mg/m² twice daily (range 0.8-2.9), while it was 0.7 to 1.6mg/m² twice daily for patients 3weeks of age to 2years. A total of 676 blood concentration data were used for the population PK analysis by nonlinear mixed effect modeling using NONMEM. The final model included a maturation function for sirolimus clearance and allometrically scaled body weight to account for size differences. The mean allometrically scaled sirolimus clearance estimates increased from 3.9 to 17.0L/h per 70kg with age from shortly after the birth to 2years of age while the mean estimate for patients older than 2years was 18.5L/h per 70kg. The developed model based dosing strategy provides a foundation for ongoing efforts to define the sirolimus exposure-response and clinical outcome relationships across the pediatric age spectrum from birth to adolescence.

Infant skin maturation: Preliminary outcomes for color and biomechanical properties

BACKGROUND

Newborn infant skin changes after birth but studies have focused on the epidermal barrier. Dermal properties are relevant for care, but literature on postnatal changes is sparse. We further characterized skin maturational changes in lightness, color and response to biomechanical stress.

METHODS

Normal skin sites from subsets of participants in a trial on the progression and stage of infantile hemangiomas were retrospectively examined. Standardized photographs were analyzed as L*, a*, and b* images. Biomechanics were measured with the Cutometer^® .

RESULTS

Color changed significantly with increasing age. Skin was darker and redder at 2.0 vs. 5.4, 8.5 and 12.8 months. Yellow color increased, with higher values at 12.8 vs. 2.0, 3.5 and 5.4 months. Chest tissue was consistently more elastic than arm and face sites, with significantly higher elasticity for the youngest and oldest age groups. Biological elasticity, elastic recovery, and total recovery were significantly greater for the oldest subjects. Viscoelasticity and elastic deformation were lower at 5.5 vs. 8.8 and 17.6 months. Arm viscoelastic creep was highest at 2.8 months.

CONCLUSION

Skin maturation continues into year two. Increasing elasticity and decreasing viscoelasticity may reflect increased collagen structure/function. The findings have implications for prevention of skin injury associated with mechanical forces.

Response of Blue Rubber Bleb Nevus Syndrome to Sirolimus Treatment

BACKGROUND

Blue rubber bleb nevus syndrome (BRBNS) is a rare multifocal venous malformation syndrome involving predominantly the skin and gastrointestinal tract. Traditional treatment modalities include corticosteroids, interferon-α, sclerotherapy, and aggressive surgical resection. Sirolimus has been used in several single case reports.

PROCEDURE

We performed a single-institution retrospective review of four children with BRBNS, who received sirolimus as part of their treatment regimens. A diagnosis of BRBNS was based on clinical, radiologic, and pathologic criteria.

RESULTS

Median age was 6.5 years (range: 2-16 years). Pathologic evaluations revealed a combined malformation with venous and lymphatic components. The novel finding of a lymphatic component was confirmed with PROX-1 immunostaining. Patients received oral sirolimus with target drug levels between 10 and 13 ng/ml. Responses to treatment were defined as stabilization/decrease in size of lesions; resolution of transfusion requirements; reduction in pain, and improvement in quality of life (QOL). Median time to response was 1.5 months (SD ± 0.96 month, range: 1-3 months). Median follow-up was 21 months (range: 18-26 months). Lesion size and characteristics improved in all patients. All patients reported decrease in pain and improvement in QOL. All three patients requiring transfusions became transfusion-independent. One patient had resolution of coagulopathy. Adverse effects of sirolimus consisted of mucositis in three patients and neutropenia in one patient.

CONCLUSIONS

Sirolimus is safe and efficient for the treatment of BRBNS. Further prospective studies are needed to evaluate the long-term effectiveness of this drug. This is the first report that identifies a lymphatic component as part of BRBNS.

Infantile hemangioma status by dynamic infrared thermography: A preliminary study

BACKGROUND

Infantile hemangiomas (IH) are initially warm due to increased proliferation and perfusion then involute with apoptosis and reduced perfusion. Objective quantitative evaluation of IH treatment response is essential for improving outcomes. We applied a functional imaging method, dynamic infrared (IR) thermography, to investigate IH status versus control skin and over time.

MATERIALS AND METHODS

A preliminary prospective observational study was conducted among 25 subjects with superficial or mixed IHs (< 19 months) over 59 clinic visits. Infrared images of IHs and control sites, standardized color images, and three-dimensional images were obtained. Tissue responses following application and removal of a cold stress were recorded with video IR thermography. Outcomes included areas under the curve during cooling (AUCcool ) and rewarming (AUCrw ) and thermal intensity distribution maps.

RESULTS

AUCcool and AUCrw were significantly higher and cooling rate slower for IHs versus uninvolved tissue indicating greater heat, presumably due to greater perfusion and metabolism for the IH. IR distribution maps showed specific areas of high and low temperature. Significant changes in IH thermal activity were reflected in the difference (AUCcool - AUCrw ), with 6.2 at 2.2 months increasing to 37.6 at 12.8 months. IH cooling rate increased with age, indicating slower recovery, and interpreted as reduced proliferation and/or involution.

CONCLUSIONS

Dynamic IR thermography was a well-tolerated, quantitative functional imaging modality appropriate for the clinic, particularly when structural changes, i.e., height, volume, color, were not readily observed. It may assist in monitoring progress, individualizing treatment, and evaluating therapies.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov (Identifier NCT02061735).

Efficacy and Safety of Sirolimus in the Treatment of Complicated Vascular Anomalies

BACKGROUND AND OBJECTIVES

Complicated vascular anomalies have limited therapeutic options and cause significant morbidity and mortality. This Phase II trial enrolled patients with complicated vascular anomalies to determine the efficacy and safety of treatment with sirolimus for 12 courses; each course was defined as 28 days.

METHODS

Treatment consisted of a continuous dosing schedule of oral sirolimus starting at 0.8 mg/m(2) per dose twice daily, with pharmacokinetic-guided target serum trough levels of 10 to 15 ng/mL. The primary outcomes were responsiveness to sirolimus by the end of course 6 (evaluated according to functional impairment score, quality of life, and radiologic assessment) and the incidence of toxicities and/or infection-related deaths.

RESULTS

Sixty-one patients were enrolled; 57 patients were evaluable for efficacy at the end of course 6, and 53 were evaluable at the end of course 12. No patient had a complete response at the end of course 6 or 12 as anticipated. At the end of course 6, a total of 47 patients had a partial response, 3 patients had stable disease, and 7 patients had progressive disease. Two patients were taken off of study medicine secondary to persistent adverse effects. Grade 3 and higher toxicities attributable to sirolimus included blood/bone marrow toxicity in 27% of patients, gastrointestinal toxicity in 3%, and metabolic/laboratory toxicity in 3%. No toxicity-related deaths occurred.

CONCLUSIONS

Sirolimus was efficacious and well tolerated in these study patients with complicated vascular anomalies. Clinical activity was reported in the majority of the disorders.

Sirolimus for the treatment of complicated vascular anomalies in children

BACKGROUND

Vascular anomalies comprise a diverse group of diagnoses. While infantile hemangiomas are common, the majority of these conditions are quite rare and have not been widely studied. Some of these lesions, though benign, can impair vital structures, be deforming, or even become life-threatening. Vascular tumors such as kaposiform hemangioendotheliomas (KHE) and complicated vascular malformations have proven particularly difficult to treat.

PROCEDURE

Here we retrospectively evaluate a series of six patients with complicated, life-threatening vascular anomalies who were treated with the mTOR inhibitor sirolimus for compassionate use at two centers after failing multiple other therapies.

RESULTS

These patients showed significant improvement in clinical status with tolerable side effects.

CONCLUSIONS

Sirolimus appears to be effective and safe in patients with life-threatening vascular anomalies and represents an important tool in treating these diseases. These findings are currently being further evaluated in a Phase II safety and efficacy trial.

Oncolytic virotherapy reaches adolescence

Lytic viruses kill cells as a consequence of their normal replication life cycle. The idea of harnessing viruses to kill cancer cells arose over a century ago, before viruses were even discovered, from medical case reports of infections associated with cancer remissions. Since then, there has been no shortage of hype, hope, or fear regarding the prospect of oncolytic virotherapy for cancer. Early developments in the field included encouraging antitumor efficacy both in animal studies in the 1920s-1940s and in human clinical trials in the 1950s-1970s. Despite its long-standing history, oncolytic virotherapy was an idea ahead of its time. Without needed advances in molecular biology, virology, immunology, and clinical research ethics, early clinical trials resulted in infectious complications and were fraught with controversial research conduct, so that enthusiasm in the medical community waned. Oncolytic virotherapy is now experiencing a major growth spurt, having sustained numerous laboratory advances and undergone multiple encouraging adult clinical trials, and is now witnessing the emergence of pediatric trials. Here we review the history and salient biology of the field, including preclinical and clinical data, with a special emphasis on those agents now being tested in pediatric cancer patients.

Activation of the Syk tyrosine kinase is insufficient for downstream signal transduction in B lymphocytes

BACKGROUND

Immature B lymphocytes and certain B cell lymphomas undergo apoptotic cell death following activation of the B cell antigen receptor (BCR) signal transduction pathway. Several biochemical changes occur in response to BCR engagement, including activation of the Syk tyrosine kinase. Although Syk activation appears to be necessary for some downstream biochemical and cellular responses, the signaling events that precede Syk activation remain ill defined. In addition, the requirements for complete activation of the Syk-dependent signaling step remain to be elucidated.

RESULTS

A mutant form of Syk carrying a combination of a K395A substitution in the kinase domain and substitutions of three phenylalanines (3F) for the three C-terminal tyrosines was expressed in a murine B cell lymphoma cell line, BCL1.3B3 to interfere with normal Syk regulation as a means to examine the Syk activation step in BCR signaling. Introduction of this kinase-inactive mutant led to the constitutive activation of the endogenous wildtype Syk enzyme in the absence of receptor engagement through a 'dominant-positive' effect. Under these conditions, Syk kinase activation occurred in the absence of phosphorylation on Syk tyrosine residues. Although Syk appears to be required for BCR-induced apoptosis in several systems, no increase in spontaneous cell death was observed in these cells. Surprisingly, although the endogenous Syk kinase was enzymatically active, no enhancement in the phosphorylation of cytoplasmic proteins, including phospholipase Cgamma2 (PLCgamma2), a direct Syk target, was observed.

CONCLUSION

These data indicate that activation of Syk kinase enzymatic activity is insufficient for Syk-dependent signal transduction. This observation suggests that other events are required for efficient signaling. We speculate that localization of the active enzyme to a receptor complex specifically assembled for signal transduction may be the missing event.