Treatment of voluminous and complicated superficial slow-flow vascular malformations with sirolimus (PERFORMUS): protocol for a multicenter phase 2 trial with a randomized observational-phase design

Vascular anomalies (VAs) include a heterogeneous group of disorders occurring most frequently in newborns and children. Infantile hemangiomas are common (10% of infants), are generally not complicated and are easily managed, but most other VAs are rare (< 2% altogether) and we have no guidelines for management.

The updated classification from the International Society for the Study of Vascular Anomalies (ISSVA), divides VAs into 2 broad categories: vascular tumors and vascular malformations (VMs) [1]. VMs are usually present at birth, although they are not always apparent at this stage; they are distinguished by their hemodynamic flow as high-flow and slow-flow VMs. Slow-flow VMs involve abnormal capillaries vessels (i.e., port-wine stains), venous vessels, lymphatic vessels (including macrocystic, microcystic or mixed lymphatic malformations) or a combination of these. They can be superficial (involving cutaneous and subcutaneous tissues, underlying fasciae and muscles) or may have visceral involvement. They can be limited or diffuse and are sometimes components of genetic syndromes (e.g., Protée, Klippel-Trenaunay, Bean syndrome) [2]. They are always due to defective embryologic vasculogenesis [3]. Slow-flow VMs are diagnosed on physical examination, but a biopsy might be required for confirmation. Diagnosis is always completed with imaging, including duplex ultrasonography for screening, and MRI for definitive diagnosis and diagnosis of extension [4]. Recent molecular findings have allowed for a better understanding of VMs, in particular those for which somatic mutations of genes were identified, especially PIK3CA, causing overgrowth tissue associated with the VM [5, 6]. Slow-flow superficial VMs might induce functional impairment because they can be voluminous, painful, associated with underlying overgrowth tissue, or complicated by seepage or continuous cutaneous bleeding. Visceral VMs can be life-threatening when complicated by gastrointestinal bleeding, for instance, or hematologic disturbances (anemia, thrombopenia).

Management of slow-flow VMs requires dedicated multispecialty care. We have no guidelines for treatment, and management may include no intervention (although the natural history of these VMs is progressive worsening), compression with a physical bandage, sclerotherapy, resection (when feasible), anti-inflammatory or anti-coagulation drugs, or interferon or anti-proliferative drugs [7, 8]. Literature reporting medical therapies for slow-flow superficial VMs consists mainly of pediatric case reports and features publication bias, inconsistent use of nomenclature and lack of clinical trials.

Mammalian target of rapamycin (mTOR) inhibitors, usually indicated as immunosuppressive agents for preventing organ rejection [9], have been recently used for VAs, given their anti-proliferative and anti-angio/lymphangiogenic properties, with very promising results [9‐12]. They directly inhibit mTOR, a serine-threonine kinase regulated by phosphoinositide-3-kinase (PIK3), which acts as a master switch in numerous cellular processes such as cell growth and proliferation, cellular metabolism, autophagy, and angio/lymphangiogenesis. Inhibitors of mTOR were found efficient in several cases of VAs [12, 13]. A systematic review recorded 84 cases of VAs treated with mTOR inhibitors up to 2014 [14].

Sirolimus (or rapamycin), which has the advantage of oral administration, was the most frequently used mTOR inhibitor and had quick efficacy in children with slow-flow VMs, with overall good tolerance. However, the sirolimus doses, monitoring and outcomes were heterogeneous. An observational study of 61 cases published since then showed more mitigated results [15]. All authors highlighted the need to perform randomized clinical trials to better delineate sirolimus indications in VMs and the modalities of posology and monitoring.

PERFORMUS is a multicentre phase 2 trial with a randomized observational-phase design derived from the design described by Feldman et al. [16]. Patients will be followed up for a total of 12 months. All will start with an observational period (no treatment), then will switch to an experimental period, when they will receive sirolimus. The switch time will be randomized, ranging from month 4 to month 8 (Fig. 1). Such a design was preferred to a two-parallel group design because it allows all children to receive treatment at some time point, thus encouraging physician adherence to the protocol and better patient acceptance. As well, it provides greater power as compared with a two-independent group trial.

The study will be conducted in 12 French tertiary hospital centers involving multidisciplinary consultations (with dermatologists, radiologists and surgeons) dedicated to VAs.

Sirolimus will be administered in oral suspension or tablets according to the patient’s age, starting with 0.08 mg/kg/day, max 2 mg/day, twice a day, with dose adjustments based on serum level of sirolimus at day 15 to reach target levels 4 to 12 ng/ml. The maximum dosage will be 6 mg per day. A pharmakocinetics model was developed for sirolimus dose adjustment and was made available for investigators via a secured website (https://​pharmaco.​chu-limoges.​fr/). The model allows for describing and predicting the evolution of drug concentrations based on individual information (measured sirolimus trough level, dose administered and patient weight) and on an a priori set of pharmacokinetics parameters (= the pharmacokinetics population model).

Sirolimus will be supplied to pharmacists at each investigational site and will be in charge of the traceability and storage. The products will be stored at room temperature (maximum 25 °C) for the tablet form and in a cool place (2 to 8 °C) for the oral suspension.

Regarding concomitant treatments, all will be allowed, except for drugs that inhibit CYP3A4 (ketoconazole, voriconazole, itraconazole, telithromycin, clarithromycin) or activate it (rifampcin, rifabutin); and for other concomitant immunosuppressive drugs (to minimize risks of infection).

Secondary outcomes are clinical and biological assessments of the efficacy of sirolimus as well as safety.

Clinical efficacy will be assessed by different endpoints (Table 1).

Two blinded independent trained readers will qualitatively assess digital photographs. For each patient, readers will be provided photographs at baseline and those at MS and M12 without informative data; they will be asked to identify which photograph was taken at the end of the observational period and which at the end of the sirolimus period. Such a procedure represents a “lady-tasting-tea” procedure [17]. Guidelines will be given to the investigators to perform, with their own camera, a front, a profile and a ¾ photograph of the VM at a 50 cm-distance, with a decimeter placed beside the malformation, the child being standing up or lying. They will be asked to send a copy of the photographs to the Clinical Investigation Center of Tours for further centralized assessment. The photographs will be previously registered with initials of the names, code of the center and inclusion number.

Clinical global improvement will be assessed by an unblinded physician on a 0–10 visual analog scale and will be self-assessed by the patient or proxy (parents) on a 0–10 visual analog scale.

Impact on complications will be self-assessed by the patient or proxy, considering pain and skin complications/symptoms (seepage, bleeding, skin tension, functional impairment) and quality of life by the dermatological quality-of-life scale (DLQI) and DLQI adapted for children (C-DLQI) [18].

Biologic markers of efficacy will include coagulation explorations (platelet count, fibrinogen level, D-dimers, factor V levels), supporting the presence and disappearance of an abnormal intravascular coagulation consumption, and plasma levels of vascular endothelial growth factor (VEGF) and tissue factor. VEGF is a major angiogenic factor that stimulates the proliferation and migration of endothelial cells. Strong expression of VEGF has been found associated with VAs, and a few reports have shown changes in serum levels of VEGF after efficient treatment for VAs and different vascularized cancers [19, 20]. Moreover, Medici et al. demonstrated that sirolimus in vitro inhibits the proliferation of hemangioma endothelial cells by reducing the expression of VEGF [21]. Hence, VEGF could be a useful biologic marker for treatment monitoring. In addition, tissue factor, a 47-kDa glycoprotein that is the physiological trigger of blood coagulation, probably has a key role in modulation of angiogenesis, particularly by regulating VEGF expression [22, 23].

Duration of participation will be 12 months for each patient. The time schedule of enrolment and visits is in Table 1.

Because each patient is his/her own control, the randomized observational-phase design is, as a cross-over design, much more powerful than a two-parallel group design. To our knowledge, we have no published data considering both our primary outcome and the target population. We plan to recruit 50 patients. Considering a correlation of 0.5 between the outcomes assessed under the observational and sirolimus period, this sample size will provide the same power as a 200-sample size two-parallel group randomized trial (i.e., 80% power to detect a 0.4 effect size, with a two-sided Type I error of 5%).

The recruitment of children with these malformations is allowed by the fact that all investigators take part in multidisciplinary consultations dedicated to VAs, including at least dermatologists or other physicians, radiologists, and surgeons. Some of them belong to the French network for research on pediatric dermatology (Groupe de Recherche de la Société Française de Dermatologie Pédiatrique).

The trial will be open-label. With the very nature of the design, blinding is artificial in some way. Indeed, everyone knows that the patient begins with an observational period and ends with a period during which they are treated. Moreover, sirolimus requires biologic monitoring to detect AEs and for dose adjustment (by measuring serum level of sirolimus). Blinding would have involved children undergoing numerous useless blood tests and also important logistical constraints because the people managing the sirolimus adjustment would have to be different from care providers. To compensate for the need for an open-label design, the primary outcome data are collected with blinding (i.e., centralized interpretation of MRI images performed by the same radiologist who will be blinded to physical assessment and treatment period).

Table 1 shows data collection according to inclusion and follow-up visits.

An e-CRF will be developed by using Ennov Clinical© software. The e-CRF will be managed in agreement with INSERM CIC 1415 Standardized Operating Procedures (SOP). Data from investigating centres will be entered by using a secure web site monitored by clinical research associates, and queries will be edited by data managers, in agreement with an a priori-specified data-management plan. Blinded review will be performed before locking the database. The database will be locked in agreement with INSERM CIC 1415 SOPs and data will be extracted in a SAS format or other, according to statistical requirements. Raw data will be stored in a XML format.

Considering the primary outcome, relative changes in volume of VMs will be compared by paired t test or Wilcoxon signed-rank test if necessary. For secondary outcomes, physician assessment of efficacy, patient self-assessment and biological relative changes will be analyzed by the same approach (i.e., paired t test or Wilcoxon signed-rank test). Considering efficacy on digital photographs, assessed by 2 independent trained readers, the “lady-tasting-tea” procedure will be used to test whether readers performed better than expected in identifying the digital photographs taken after the end of the sirolimus period [17]. Regarding AEs, descriptive statistics (percentages) will be estimated. The ancillary study on genetic samples will be descriptive.

A clinical research technician will be responsible for coordination of the study: will be responsible for the logistics of and monitoring the study; producing reports concerning its state of progress; verifying that the e-CRFs are updated (request for additional information, corrections, etc.); sending blood and skin samples; and transmitting severe AEs to the sponsor. The technician will follow the SOPs.

A data safety monitoring board (DSMB) composed of 3 medical doctors specialized in pharmaco-toxicology, pharmaco-dermatology and pediatric dermatology, is an advisory committee responsible for giving its opinion to the sponsor and the coordinator investigator on the benefit/risk ratio of the trial. The DSMB will be systematically contacted in the following situations: at any time by the sponsor for each case of expected serious adverse reaction or for an suspected unexpected serious adverse drug reaction (SUSAR); before each development safety update report is sent to the French Agency for the Safety of Health Products (ANSM); and if data may change the benefit/risk ratio during the clinical trial.

All AEs will be monitored until they are completely resolved. The investigator will immediately notify the sponsor of any serious AE. The sponsor will report all SUSARs to the Eudravigilance (European pharmacovigilance database), French health authorities (ANSM), and the investigators within the regulatory time periods for reporting.

An audit may be performed at any time by sponsor-appointed people who are independent of those responsible for the study. The aim of an audit is to ensure good quality of the study, the validity of results and that the law and regulations in force are well observed. The investigators agree to comply with the requirements of the sponsor and the relevant authority for an audit or inspection of the study. The audit can apply at all stages of the study, from development of the protocol to publication of results.

The sponsor and the investigators undertake to conduct this study in compliance with French law no. 2004–806 of August 9, 2004 and following Good Clinical Practice and the Helsinki Declaration (Ethical Principles for Medical Research involving Human Subjects, Tokyo 2004). The study will be conducted in accordance with this protocol. With the exclusion of emergency situations requiring specific therapeutic actions, the investigators will observe the protocol in all respects, particularly in obtaining consent and the notification and follow-up of serious AEs.

The protocol was approved by the institutional review board of the University Hospital Centre of Tours (#2015-R18) and received authorization from ANSM.

Important protocol modifications will be submitted as well for approval to the Institutional review board of the University hospital of Tours, and will be communicated to coinvestigators.

Both parents will give their informed signed consent after their child has consented (if able) and they have been orally informed of the study and have received a written information form (Additional file 1). These potential participants are informed that they are free to withdraw from the study at any moment.

During this biomedical research study or when it is over, the information collected on the people taking part in it and forwarded to the sponsor by the investigators (or any other specialized staff member involved) will be made anonymous. Under no circumstances will the uncoded names or addresses of the people concerned appear in any data.

The sponsor is responsible for obtaining agreement from all the parties involved in the study in order to guarantee direct access, in all the sites where the study is being conducted, to source data, source documents and reports, to control their quality and to audit them.

The investigators will make available to people with a right of access to these documents, according to the legislative and regulatory provisions in force (articles L.1121–3 and R.5121–13 of the French Public Health Act), the documents and individual data strictly necessary for monitoring, carrying out quality control and auditing the biomedical research.

INSERM CIC 1415 Tours will analyze the data provided by the study centres. Results will be displayed in a written report that will be submitted to the sponsor. At the end of the analysis, results will be published in ClinicalTrials.​gov. The international rules for writing and publication (Vancouver Agreement, February 2006) will be followed.

In accordance with law no. 2002–303 of March 4, 2002, patients will be informed, at their request, about the overall results of the study [25].

This protocol has been written in accordance with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidelines. The SPIRIT checklist is in Additional file 2. The SPIRIT figure is in Additional file 3.

The protocol is currently recruiting in 12 French centres. The first patient was included on December 30, 2016, and recruitment is anticipated to end in March 2018, with follow-up completed in March 2019.