Severe adverse events during sirolimus "off-label" therapy for vascular anomalies

Real-World Data on the Use of Sirolimus in Asian Children with Vascular Malformations

OBJECTIVES

The management of vascular malformations is complex and challenging. This study aimed to explore efficacy, plasma trough concentrations of sirolimus, post-withdrawal conditions, and adverse reactions of sirolimus in treating complex vascular malformations.

METHODS

In our center, we analyzed vascular malformations treated with sirolimus (and corticosteroid) from August 2017 to June 2021. Meanwhile, we reviewed the medical records, the efficacy, side effects, and laboratory tests. Patients who had stopped taking sirolimus were followed up by telephone.

RESULTS

A total of 25 patients with complicated vascular malformations in our center, including 7 females and 18 males aged 4 months to 15 years, were enrolled. In all, 19 patients (76.0%) responded to sirolimus, and the plasma concentration of sirolimus fluctuated between 0.97 and 27.15 ng/ml. In all, 24 patients (96.0%) were in follow-up. A total of 15 patients (62.5%) stopped taking sirolimus during follow-up, and 2 patients (13.3%) discontinued the sirolimus due to side effects. A total of 3 patients (20.0%) restarted sirolimus treatment.

CONCLUSION

Starting dose of 1.5-2 mg/m2 sirolimus is effective and safe in vascular malformation treatment. The best treatment regimen and discontinuation indications needed more investigation. Most should be done about targeted therapy to improve effectiveness and reduce side effects.

Sirolimus for Pediatric Cervicofacial Lymphatic Malformation: A Systematic Review and Meta-Analysis

OBJECTIVE

This study is a systematic review and meta-analysis of the efficacy and safety of sirolimus in the management of pediatric cervicofacial lymphatic malformations (LMs).

DATA SOURCES

EMBASE, Medline, Scopus, and Cochrane databases were searched, along with the reference list of all included articles.

REVIEW METHODS

The study protocol was registered with PROSPERO and a systematic literature search strategy was designed and conducted with the aid of a medical librarian. All studies including case reports were included, with pooled analysis of raw data. A meta-analysis was conducted of magnetic resonance imaging (MRI), clinical, and airway outcomes.

RESULTS

Thirteen case series and five individual case reports were included. Meta-analysis showed 78% (95% CI 57%-94%) of 62 patients had a reduction in LM volume, on MRI criteria, by 20% or more, and 32% (95% CI 11%-57%) had a reduction of 50% or more. Further meta-analysis showed 97% (95% CI 88%-100%) of 78 patients reported some clinical improvement on sirolimus. Sirolimus may be of particular value in management of airway LMs; out of 27 tracheostomy-dependent patients, meta-analysis showed 33% (95% CI 1%-78%) were decannulated after starting sirolimus. Individual patient meta-analysis on 24 individuals showed a statistically significant better response to sirolimus when initiated under the age of 2 years.

CONCLUSION

This review and meta-analysis support the efficacy of sirolimus in pediatric LMs of the head, neck, and airway. A large multi-center trial is needed to further explore its role and limitations. Laryngoscope, 134:2038-2047, 2024.

Sirolimus treatment for intractable lymphatic anomalies: an open-label, single-arm, multicenter, prospective trial

Introduction

Intractable lymphatic anomalies (LAs) include cystic lymphatic malformation (LM; macrocystic, microcystic, or mixed), generalized lymphatic anomaly, and Gorham-Stout disease. LAs can present with severe symptoms and poor prognosis. Thus, prospective studies for treatments are warranted. We conducted a prospective clinical trial of sirolimus for intractable LAs.

Methods

This was an open-label, single-arm, multicenter, prospective trial involving five institutions in Japan. All patients with LAs received oral sirolimus once daily, and the dose was adjusted to ensure that the trough concentration remained within 5-15 ng/mL. We prospectively assessed the drug response (response rate for radiological volumetric change in target lesion), performance state, change in respiratory function, visceral impairment (pleural effusion, ascites, bleeding, pain), laboratory examination data, quality of life (QOL), and safety at 12, 24, and 52 weeks of administration.

Results

Eleven patients with LAs (9 generalized lymphatic anomaly, 1 cystic LM, 1 Gorham-Stout disease) were treated with sirolimus, of whom 6 (54.5%; 95% confidence interval: 23.4-83.3%) demonstrated a partial response on radiological examination at 52 weeks of administration. No patients achieved a complete response. At 12 and 24 weeks of administration, 8 patients (72.7%) already showed a partial response. However, patients with stable disease showed minor or no reduction after 12 weeks. Adverse events, such as stomatitis, acneiform dermatitis, diarrhea, and fever, were common with sirolimus. Sirolimus was safe and tolerable.

Conclusion

Sirolimus can reduce the lymphatic tissue volume in LAs and may lead to improvements in clinical symptoms and QOL.

Sirolimus for vascular anomalies in the first year of life: a systematic review

Evidence on effectiveness and safety of sirolimus in congenital vascular anomalies in infancy is lacking. We aim to systematically review the efficacy and safety of sirolimus in treating congenital VA in infancy. We searched for and included all studies evaluating sirolimus for VA in the first year of life. The primary outcome was effectiveness. The secondary outcome was safety. We included 84 case series and reports (172 participants). Sirolimus decreased the size of the VA in >50% of participants, most of whom had minor transient side effects, and 27% had no adverse effects at all. When categorized by age (<1 month, 1-5 months and 6-12 months), the effectiveness was similar in all age groups. Available evidence suggests that sirolimus is effective and well tolerated. The effectiveness of sirolimus should be evaluated in a well-designed randomized controlled or observational studies.

Infectious complications of vascular anomalies treated with sirolimus: A systematic review

BACKGROUND AND OBJECTIVES

Initially developed as immunosuppressive agents, mammalian target of rapamycin (mTOR) inhibitors are currently used widely in the management of vascular malformations and tumors. The incidence of infectious complications in the vascular anomalies (VA) population is not well defined. The goal of this systematic review was to better define the types and severity of reported infectious complications in patients with VAs treated with mTOR inhibition.

METHODS

This was a systematic review conducted following PRISMA guidelines evaluating all research articles focused on infectious complications in patients with VAs treated with sirolimus or everolimus. Thirty articles including 1182 total patients and 316 infections (in 291 unique patients) were ultimately included.

RESULTS

The majority of infections were viral upper respiratory (n = 137, 54%), followed by pneumonia (n = 53, 20%), and cutaneous infections (n = 20, 8%). There were six total infection-related fatalities, which all occurred in patients younger than 2 years. Two cases of Pneumocystis jirovecii pneumonia (PJP) were reported. These were infants with kaposiform hemangioendothelioma (KHE) who were also treated with steroids and did not receive PJP prophylaxis. Almost one-third (n = 96, 32%) of infectious complications were graded 3-4 according to Common Terminology Criteria for Adverse Events (CTCAE) criteria. Details of patient age, subtype of VA, and timing of infection were lacking from many reports.

CONCLUSIONS

Most infectious complications reported in patients with VA on mTOR inhibitors were viral respiratory infections and non-severe. Bacteremia, infectious fatalities, and PJP are exceedingly rare. Future studies are needed to clarify the spectrum of infectious risks in VA patients and to provide guidance for infection prevention.

Alpelisib for treatment of patients with PIK3CA-related overgrowth spectrum (PROS)

PURPOSE

PIK3CA-related overgrowth spectrum (PROS) encompasses several rare conditions resulting from activating variants in PIK3CA. Alpelisib, a PI3Kα-selective inhibitor, targets the underlying etiology of PROS, offering a novel therapeutic approach to current management strategies. This study evaluated the safety and efficacy of alpelisib in pediatric and adult patients with PROS.

METHODS

EPIK-P1 (NCT04285723) was a non-interventional, retrospective chart review of 57 patients with PROS (≥2 years) treated with alpelisib through compassionate use. Patients had severe/life-threatening PROS-related conditions and confirmed PIK3CA pathogenic variant. The primary end point assessed patient response to treatment at Week 24 (6 months).

RESULTS

Twenty-four weeks (6 months) after treatment initiation, 12 of 32 (37.5%) patients with complete case records included in the analysis of the primary end point experienced a ≥20% reduction in target lesion(s) volume. Additional clinical benefit independent from lesion volume reduction was observed across the full study population. Adverse events (AEs) and treatment-related AEs were experienced by 82.5% (47/57) and 38.6% (22/57) of patients, respectively; the most common treatment-related AEs were hyperglycemia (12.3%) and aphthous ulcer (10.5%). No deaths occurred.

CONCLUSION

EPIK-P1 provides real-world evidence of alpelisib effectiveness and safety in patients with PROS and confirms PI3Kα as a valid therapeutic target for PROS symptom management.

Mental and physical health of adult patients affected by complex vascular anomalies

OBJECTIVE

We examined care and communication factors that affect physical and mental health for patients with complex vascular anomalies (VAs).

METHODS

VA patients (N = 135) completed an online survey with measures of ability to navigate healthcare, quality of information exchange, perceived stigma, and demographic variables. We performed linear regression to determine if these variables were associated with mental and physical health.

RESULTS

Physical and mental health were associated with information exchange (β = .41, 95% CI=.12 -.69; β = .33, 95% CI=.04 -.62), stigma (β = -.49, 95% CI=-.74 to -.24; β = -.63, 95% CI=-.89 to -.38), and education (β = 4.00, 95% CI=.63 - 7.38; β = 3.44, 95% CI=.06 to 6.82). Ability to navigate healthcare was associated with health outcomes in our bivariate model, but not significant in a multivariate model.

CONCLUSION

The results underscore the importance of effective information exchange. Poor information exchange was associated with worse physical and mental health. VA patients with lower education levels and higher perceived stigma reported poorer health outcomes and likely face many struggles accessing care.

PRACTICE IMPLICATIONS

Patient-centered information exchange between clinicians and patients is needed to address unmet information needs. Clinicians can also reduce perceived stigma by validating patients, and should provide resources to reduce disparities related to education.

Indication for a Pneumocystis Prophylaxis Therapy in Patients with Vascular Anomalies Treated with PIK3/AKT/mTOR Pathway Inhibitors: Experts' Opinion and Systematic Review from the Literature

BACKGROUND

Vascular anomalies (VAs) are increasingly being treated with PI3K/AKT/mTOR pathway inhibitors. These drugs have immunosuppressive properties and thus theoretically overexpose patients to opportunistic infections, especially Pneumocystis jirovecii pneumonia (PJP). PJP prophylaxis use lacks consensus. We aimed to investigate the prevalence of PJP in patients receiving mTOR/PI3K/AKT inhibitors for VAs and determine any indication for pneumocystis prophylaxis in this population.

METHODS

The study was conducted in 2 parts: (1) we sent a survey to a panel of international experts of VAs asking about their use of pneumocystis prophylaxis drugs and (2) we performed a systematic review of the literature of all published cases of patients receiving these drugs for VA to estimate the prevalence of PJP in this population.

RESULTS

Answers from 68 experts were analyzed: 21 (30.9%) answered they always add PJP prophylaxis when prescribing mTOR inhibitors, 20 (29.4%) case-by-case, and 27 (39.7%) never. For the systematic review, among 3,053 reports screened, 217 were included involving 1,189 patients (1,143 received sirolimus, 38 everolimus, 4 alpelisib, 4 miransertib). Among the 1,189 cases, 2 (0.2%) PJP were reported: one under sirolimus and one under everolimus. Thus, the prevalence of PJP was estimated at 0.88 cases/1,000 patients under sirolimus (95% CI: -0.84 to 2.59) and 26.31 cases/1,000 under everolimus (95% CI: -24.58 to 77.18). Patients with PJP never received prophylaxis drugs. We found no PJP cases under alpelisib and miransertib. PJP prophylaxis was given in 218 (18.3%) cases, more frequently for children (91.3 vs. 77.2% in the non-prophylaxis group, p = 0.012), mostly trimethoprim-sulfamethoxazole (186 patients, 85.3%).

CONCLUSION

Our study shows that even if PJP is a rare event, it may occur in patients with VAs treated with an mTOR inhibitor. Although our results cannot allow for revising guidelines, prophylaxis with TMP-SMX might be appropriate for a subgroup of patients with risk factors for PJP.

Influence of genetic variants on the pharmacokinetics and pharmacodynamics of sirolimus: a systematic review

Sirolimus is an antiproliferative and immunosuppressive compound inhibiting the mTOR pathway, which is often activated in congenital low-flow vascular malformations. Studies have demonstrated the efficacy of sirolimus for this disease. Studies in kidney transplant patients suggest that genetic variants can influence these pharmacokinetic parameters. Therefore, a systematic literature search was performed to gain insight into pharmacogenetic studies with sirolimus. Most studies investigated CYP3A4 and CYP3A5, with inconsistent results. No pharmacogenetic studies focusing on sirolimus have been performed for low-flow vascular malformations. We analyzed two common variants of CYP3A4 and CYP3A5 (CYP3A4*22 and CYP3A5*3, respectively) in patients (n = 59) with congenital low-flow vascular malformations treated with sirolimus. No association with treatment outcome was identified in this small cohort of patients.

Oral antibiotic prophylaxis for infection in patients with vascular anomalies receiving sirolimus treatment: a multicenter retrospective study

OBJECTIVES

Patients with vascular anomalies (VAs) who receive oral sirolimus may be at high risk of infectious complications. Antibiotic prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMZ) has been advocated. However, there have been few evidence-based analyses on this topic. This study assessed the effect of prophylactic TMP-SMZ on the incidence of infections in VA patients receiving sirolimus monotherapy.

METHODS

A retrospective, multicenter chart review was performed on all VA patients receiving sirolimus treatment from August, 2013 to January, 2021.

RESULTS

Before January 2017, 112 patients were treated with sirolimus without antibiotic prophylaxis. In the subsequent period, 195 patients were treated with TMP-SMZ for at least 12 months during sirolimus therapy. The percentage of patients with at least one serious infection during the initial 12 months of sirolimus treatment did not differ between the groups (difference, 1.1%; 95% CI - 7.0-8.0%). We observed no difference in the incidence of individual infection or total adverse events between the groups. The rate of sirolimus discontinuation due to adverse events did not differ significantly between groups.

CONCLUSIONS

We demonstrated that prophylactic TMP-SMZ does not decrease the incidence of infection or improve tolerance in VA patients receiving sirolimus monotherapy.

Clinical differences in sirolimus treatment with low target levels between children and adults with vascular malformations - A nationwide trial

The clinical presentation of patients with slow-flow vascular malformations is very heterogeneous. High clinical burden and subsequent reduced health-related quality of life is something they have in common. There is an unmet medical need for these patients for whom regular treatments like surgery and embolization are either insufficient or technically impossible. Sirolimus has been reported to be effective and overall well-tolerated in most patients. However, the main limitation of sirolimus is the reported high toxicity, especially when target levels of 10-15 ng/mL are being used. We report the results of a phase IIB single-arm open-label clinical trial consisting of 68 (67 in the challenge phase and 68 in the rechallenge phase) evaluable patients (children n = 33 and adults n = 35) demonstrating that treatment with low sirolimus target levels (4-10 ng/mL) is effective in 79.1% of the patients. When sirolimus treatment was stopped, the majority of patients experienced a recurrence of symptoms, supporting prolonged or even lifelong treatment requirement. Adults experienced a higher baseline pain score compared with children, having an estimated marginal mean of 6.2 versus 4.1, p < 0.05; however, they showed a similar decrease to children. Furthermore, the pediatric population experienced less often a sirolimus-related grade I-IV adverse event (35.9% vs. 64.1%, p > 0.05) compared with adults. Additionally, response rates were higher in children compared with adults (93.8% vs. 65.7%, p < 0.05), and children responded faster (28 vs. 91 days, p < 0.05). These results suggest benefits of sirolimus in patients with slow-flow vascular malformations and support its initiation as young as possible.

Efficacy of sirolimus in children with lymphatic malformations of the head and neck

Purpose

Children with extensive lymphatic malformations of the head and neck often suffer from functional impairment and aesthetic deformity which significantly affect the quality of life and may be life-threatening. Treatment with sirolimus has the potential to improve symptoms and downsize lymphatic malformations. This systematic review summarizes the current information about sirolimus treatment of lymphatic malformations of the head and neck in children, its efficacy and side effects.

Methods

A systematic search of the literature regarding studies on sirolimus treatment of children with lymphatic malformations of the head and neck was performed in PubMed, Embase, and Google Scholar up to July 2021 with the search terms “lymphatic malformation”, “lymphangioma”, “cystic hygroma”, “low-flow malformation”, “sirolimus”, “rapamycin”, “mTOR inhibitor” and “children”.

Results

In all, 28 studies including 105 children from newborn to 17 years treated with sirolimus for lymphatic malformations of the head and neck were analyzed. The most frequent initial dose was 0.8 mg/m² per dose, twice daily at 12-h interval. The target blood level differed between studies, 10–15 ng/mL and 5–15 ng/mL were most often used. More than 91% of the children responded to sirolimus treatment which lasts from 6 months to 4 years. Typical side effects were hyperlipidemia, neutropenia and infections.

Methods

Sirolimus could be an effective treatment for children with large complicated lymphatic malformations of the head and neck. As not all patients will benefit from treatment, the decision to treat sirolimus should be made by a multidisciplinary team.

Malignant Superficial Mesenchymal Tumors in Children

Malignant superficial mesenchymal tumors are a very diverse group of neoplasms with few clinical and radiological discriminatory factors. Hence, some of these cancers are rarely suspected based on clinical and radiological grounds, others may be easily misdiagnosed, and the histological analysis of a biopsy or resection is central in the diagnostic process. In children, the age at presentation is a major element of the differential diagnosis. Some tumors have a very distinct epidemiology, while others may be seen at any age. More recently, the advances in molecular biology have greatly improved the diagnosis of mesenchymal tumors and new entities are still being described. In the present review, we provide an overview of the diversity of malignant superficial mesenchymal tumors in children, including new and/or rare entities. We discuss the important diagnostic features, be they clinical, histological, or molecular. Special attention was given to the genetic features of these tumors, particularly when they were helpful for the diagnosis or treatment.

Sirolimus plus prednisolone vs sirolimus monotherapy for kaposiform hemangioendothelioma: a randomized clinical trial

The Kasabach-Merritt phenomenon (KMP) in kaposiform hemangioendothelioma (KHE) is characterized by life-threatening thrombocytopenia and consumptive coagulopathy. This study compared the efficacy and safety of sirolimus plus prednisolone versus sirolimus monotherapy as treatment strategies for KHE with KMP in the largest cohort to date. Participants were randomized to receive either sirolimus in combination with a short course of prednisolone or sirolimus monotherapy for at least 12 months. The primary outcome was defined as achievement of a durable platelet response (platelet count >100×109/L) at week 4. Participants completed efficacy assessments 2 years after the initial treatment. At week 4, a durable platelet response was achieved by 35 of 37 patients given sirolimus and prednisolone compared with 24 of 36 patients given sirolimus monotherapy (difference 27.9%; 95% CI, 10.0% to 44.7%). Compared with the sirolimus monotherapy group, the combination treatment group showed improvements in terms of measures of durable platelet responses at all points during the initial 3-week treatment period, median platelet counts during weeks 1 to 4, increased numbers of patients achieving fibrinogen stabilization at week 4, and objective lesion responses at month 12. Patients receiving combination therapy had fewer blood transfusions and a lower total incidence of disease sequelae than patients receiving sirolimus alone. The frequencies of total adverse events and grade 3-4 adverse events during treatment were similar in both groups. The responses seen in patients with KHE with KMP were profound and encouraging, suggesting that sirolimus plus prednisolone should be considered a valid treatment for KHE with KMP. ClinicalTrial.gov, number NCT03188068.

Targeted treatment of vascular anomalies

Vascular anomalies comprise an array of congenital developmental disorders that can lead to significant disfigurement and physiologic disarray. The vast multitude of clinical phenotypes has inherently led to misdiagnosis and patients and families enduring long diagnostic odysseys of medical care. Although the observed variation in disease manifestations remains poorly understood, targeted next-generation sequencing has pivoted our understanding of the pathobiology of vascular anomalies and, for the first time, uncovered potential pharmacologic targets for these disorders. In this review article, we highlight current and developing targeted therapies for vascular anomalies, namely phosphoinositide 3-kinase and mitogen-activated protein kinase pathway inhibitors, and discuss the future directions of targeted therapies.

Effective low dose sirolimus regimen for kaposiform hemangioendothelioma with Kasabach-Merrit Phenomenon in young infants

AIM

Management of kaposiform hemangioendotheliomas (KHE) with Kasabach-Merrit phenomenon is challenging in young infants who are subjected to developmental pharmacokinetic changes. Sirolimus, sometimes combined with corticosteroids, can be used as an effective treatment of KHE. Simultaneously, toxicities like interstitial pneumonitis related to the use of sirolimus may be fatal. As infants have a very low CYP3-enzyme expression at birth, which rises during ageing, we hypothesize, that a reduced metabolization of sirolimus might lead to high sirolimus serum levels and low dose may be sufficient without the side effects.

METHODS

A case series of five infants with kaposiform hemangioendothelioma with Kasabach-Merrit phenomenon was analysed retrospectively. All infants were treated with sirolimus - 0.2 mg/m2 every 24 or 48 hours according to their age. Prednisone was added to the therapy for additional effect in four patients.

RESULTS

In all patients low dose of sirolimus led to therapeutic sirolimus levels (4-6 ng/mL). All infants (aged 4 days - 7 months) had a complete haematological response, without serious adverse events. In all patients, the Kasabach-Merrit phenomenon resolved, the coagulation profile normalized and tumour size reduction was seen.

CONCLUSION

Low dose sirolimus treatment is safe for infants with kaposiform hemangioendothelioma and Kasabach-Merit phenomenon. Essential is to realize that during the first months of life, metabolism is still developing and enzymes necessary to metabolise drugs like sirolimus still have to mature. To avoid toxic levels, the sirolimus dosage should be based on age and the associated pharmacological developments.

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.

Patients with Congenital Low-Flow Vascular Malformation Treated with Low Dose Sirolimus

INTRODUCTION

Patients with congenital vascular malformations often suffer from an impaired quality of life (QoL) because of pain and functional disabilities. Previous studies have shown that the mTOR inhibitor sirolimus can reduce complaints and improve QoL in some patients. High target levels of sirolimus of 10-15 ng/ml were well tolerated; however, in a relative high percentage of patients sirolimus caused serious adverse events (AEs).

METHODS

A case series of 12 patients with therapy-resistant low-flow vascular malformations was treated with sirolimus, using low target levels of 4-10 ng/ml. Efficacy of sirolimus was evaluated in regard to pain symptoms using the visual analogue scale/numeric rating scale and patients reported QoL. To rule out a placebo effect of sirolimus, sirolimus was stopped after a certain time point and reintroduced as soon as complaints returned. Adverse events were closely monitored and graded using the Common Terminology Criteria for Adverse Events (CTCAE) grading.

RESULTS

An improvement in symptoms was seen in 92% (n = 11/12) of patients. In nine patients pain complaints returned. Seven out of nine of them (78%) again experienced a reduction of symptoms after restarting sirolimus treatment. Despite low target levels, these response rates are comparable to those found in the literature using higher target levels of sirolimus. However, significantly less serious AEs were observed with low dose sirolimus, suggesting low dose sirolimus might be safer. Unfortunately, young adolescent female patients developed serious menstrual disturbances during treatment with low dose sirolimus. We describe this adverse event for the first time in patients with congenital vascular malformations and this might be specifically related to low dose sirolimus.

CONCLUSIONS

Low dose sirolimus showed a high efficacy in patients with therapy-resistant and low-flow malformation, with a lower incidence of serious adverse events. At the same time a new adverse event, namely menstrual cycle disturbance, was observed in young adolescents, indicating the need for caution when sirolimus is given. This is extremely relevant to patients with low-flow vascular malformation, who are likely to require lifelong treatment for their condition.

Operative Management of Neonatal Lymphatic Malformations: Lesson Learned From 57 Consecutive Cases

Aim of the study: Lymphatic malformations (LMs) are rare entities, sometimes difficult to treat, that may be life-threatening when intricately connected to airway structures. Invasive treatments are occasionally required, with sclerotherapy considered the treatment of choice and surgery as a second-line approach. The aim of the present study was to evaluate our multidisciplinary team experience in treating newborns affected by LMs requiring operative management, while defining early outcomes. Methods: Retrospective review of all consecutive patients admitted for LMs requiring operative management between January 2000 and January 2019. Patients were mainly characterized based on anatomical district of the LM (and further stratified based on the development of respiratory distress), need for tracheostomy, number of sclerotherapies, indication for surgery, and residual disease beyond the 1st year. Morbidity and mortality were also evaluated. Fisher exact test and Mann-Whitney test were used as appropriate. Statistical significance was set at p < 0.05. Results: Fifty-seven patients were included in the study, 36 with cervicofacial and/or mediastinal LMs and 21 with LMs of other anatomical districts. Due to the risk of developing respiratory distress at birth, patients with cervicofacial and/or mediastinal LMs were divided into two groups (8/36 group A vs. 28/36 group B). Group A patients are at higher risk for tracheostomy (7/8 group A vs. 1/28 group B, p = 0.0001) and more often require surgical reduction of the residual lymphatic abnormality (5/8 group A vs. 4/28 group B, p = 0.013). They also require sclerotherapies more often, but the difference is not statistically significant (8/8 group A vs. 19/28 group B, p = 0.15). Patients with cervicofacial/mediastinal LMs frequently suffer from persistent residual disease beyond the 1st year of life, significantly more often in group A (7/8 group A vs. 12/28 group B, p = 0.043). Conclusion: LMs are rare conditions with potential life-threatening behavior. Their intrinsic clinical complexity requires a multidisciplinary approach to the affected patients. Planning a long-term follow-up is essential because of the late-term problems those patients may experience.

Efficacy of Sirolimus in Patients Requiring Tracheostomy for Life-Threatening Lymphatic Malformation of the Head and Neck: A Report From the European Reference Network

Extensive lymphatic malformations (LMs) of the head and neck region may require tracheostomy to secure the airway. Treatment of these life-threatening LMs is usually multimodal and includes sclerotherapy and surgery, among others. Recently, systemic therapy with sirolimus has been introduced as an effective treatment for venous and lymphatic malformations; its efficacy and safety profile in patients with extensive LM requiring tracheostomy are, however, as yet not fully known. We performed a retrospective, multicenter review and identified 13 patients with an extensive LM of the head and neck region, who previously underwent placement of tracheostomy and subsequently received sirolimus treatment with the aim to improve the local respiratory situation and remove the tracheostomy. Under sirolimus therapy, tracheostomy could be reversed in 8/13 (62%) patients, a further 2/13 (15%) patients improved markedly, and removal of the tracheostomy was planned at the time of writing, while 3/13 (23%) patients showed insufficient or absent response to sirolimus, rendering tracheostomy reversal not feasible. The median duration of sirolimus treatment until removal of tracheostomy was 18 months (range, 8 months to 5.6 years). Adverse events of sirolimus therapy were common [10/13 (77%) patients], yet the majority of these were mild [9/10 (90%) patients] and only one severe adverse event was recorded, with ulceration and necrosis at a catheter insertion site. In conclusion, sirolimus can be considered an effective and safe salvage treatment in patients with extensive LM even after placement of a tracheostomy, as closure of the latter was possible in the majority of patients (62%) of our retrospective cohort. A better understanding of when to start sirolimus therapy, of the duration of treatment, and of factors allowing the prediction of treatment response will require further investigation.