The Evaluation of Cytokines and Hormones as Biomarkers for Epithelioid Haemangioendothelioma and Generation of Patient-derived Preclinical Models to Assess the Activity of Anticancer Agents and Validate Novel Therapeutic Targets
Conditions: Clinical Presentation, Natural History, Treatment Outcomes
Sponsor: Fondazione IRCCS Istituto Nazionale dei Tumori, Milano

 
 
 
 
 
 
Protocol 
 
A prospective international observational study on 
Epithelioid Haemangioendothelioma 1/describing the 
clinical presentation, natural history, and treatment 
outcomes, 2/evaluating cytokines and hormones as 
biomarkers and 3/generating patient-derived preclinical 
models as a tool to assess the activity of anticancer 
agents and validate novel therapeutic targets 
 
NCT 06680401  
22 May 2025 
 
 
 
 
 

 
 

  
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A 
PROSPECTIVE 
INTERNATIONAL 
OBSERVATIONAL 
STUDY 
ON 
EPITHELIOID HEMANGIOENDOTHELIOMA: 1/DESCRIBING THE CLINICAL 
PRESENTATION, NATURAL HISTORY, AND TREATMENT OUTCOMES; 
2/EVALUATING 
CYTOKINES 
AND 
HORMONES 
AS 
BIOMARKERS; 
3/GENERATING PATIENT-DERIVED PRECLINICAL MODELS AS A TOOL TO 
ASSESS THE ACTIVITY OF ANTICANCER AGENTS AND VALIDATE NOVEL 
THERAPEUTIC TARGETS (POEM).  
 
Short Title 
POEM 
Study drugs: 
NA 
Trial number 
NCT 06680401 
Protocol Number/Version/Date:  
Version 6.0 
May, 22nd 2025 
PI’s Name and  
Legal Address 
Silvia Stacchiotti 
Medical Oncologist 
Fondazione IRCCS Istituto Nazionale dei Tumori 
Via G. Venezian 1 – 20133, Milan - Italy  
PI’s Phone 
+39 0223902803 
PI’s email 
silvia.stacchiotti@istitutotumori.mi.it  
Steering committee 
• 
Silvia Stacchiotti, Fondazione IRCCS Istituto Nazionale dei Tumori, 
Milan – Italy 
• 
Anna Maria Frezza, Fondazione IRCCS Istituto Nazionale dei 
Tumori, Milan – Italy 
• 
Claudia Giani, Fondazione IRCCS Istituto Nazionale dei Tumori, 
Milan – Italy 
• 
Sandro Pasquali, Fondazione IRCCS Istituto Nazionale dei Tumori, 
Milan – Italy 
• 
Paul Huang, The Institute of Cancer Research, London – UK  
• 
Lorenzo D’Ambrosio, Università di Torino, Torino – Italy 
• 
Robin Jones, Royal Marsden Hospital, London – UK  

  
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• 
Rosalba Miceli, Fondazione IRCCS Istituto Nazionale dei Tumori, 
Milan – Italy  
• 
Carlo Morosi, Fondazione IRCCS Istituto Nazionale dei Tumori, 
Milan – Italy 
• 
Andrea Vanzulli, Fondazione IRCCS Istituto Nazionale dei Tumori, 
Milan – Italy 
Methodology 
Prospective, international, observational study 
Type 
No Profit  
Laboratory sites 
Molecular Pharmacology Unit, Fondazione IRCCS Istituto Nazionale dei 
Tumori, Via G A Amadeo, 42 20133 Milan, ITALY  
The Institute of Cancer Research, 123 Old Brompton Road, London, UK 
Funding 
EHE Rare Cancer Charity 
 
Confidentiality statement:  
The following confidential information is the property of the Sponsor. As long as the information contained in this 
protocol has not been published, it may only be used when permission has been obtained from the Sponsor. It is 
not possible to make reproductions of all or sections of this protocol. Commercial use of the information is only 
possible with the permission of the proprietor and is subject to a license fee.  
 
 
 

  
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Table of contents: 
 
1. 
RATIONALE AND BACKGROUND 
6 
2. 
RESEARCH OBJECTIVES 
10 
2.1. 
Clinical research objectives 
10 
2.2. 
Translational research objectives 
10 
3. 
STUDY DESIGN 
11 
3.1. 
Pathological review 
12 
3.2. 
Clinical assessments and data collection 
13 
3.2.1. 
Baseline 
13 
3.2.2. 
Clinical monitoring 
14 
3.2.3. 
Radiologic assessment 
17 
3.2.4. 
Pain assessment 
17 
3.2.5. 
Progression 
18 
4. 
STUDY POPULATION 
19 
4.1. 
Inclusion criteria 
19 
4.2. 
Exclusion criteria 
19 
5. 
TRANSLATIONAL STUDY 
19 
5.1. 
Circulating cytokines (limited to INT, Milan, UNITO and ICR/ RMH, London) 
22 
5.2. 
Circulating hormone profiles (limited to INT, Milan, UNITO, and ICR/RMH, London) 
22 
5.3. 
Circulating miRNA profiles (limited to INT, Milan, UNITO, and ICR/RMH, London) 
22 
5.4. 
Multi-omic analysis of EHE clinical samples (limited to INT, Milan, UNITO, and ICR/RMH, 
London) 
23 
5.5. 
Immunohistochemistry 
23 
5.6. 
PDX model generation (limited to INT, Milan, and ICR/RMH, London) 
23 
5.7. 
CRISPR whole genome screen (limited to INT, Milan, and ICR/RMH, London) 
24 
6. 
STATISTICAL ANALYSIS 
24 
7. 
PROTECTION OF HUMAN SUBJECTS 
26 
7.1. 
Independent Ethics Committee (IEC) or Institutional Review Board (IRB) 
26 
7.2. 
Management of Patient Data 
27 
8. 
QUALITY CONTROL 
27 
8.1. 
Data quality 
27 
8.2. 
Quality review 
28 
REFERENCES 
29 
APPENDIX 1 
32 
1. 
RATIONALE AND BACKGROUND 
32 
2. 
OBJECTIVES 
34 
2.1. 
Primary objective. 
34 
2.2. 
Secondary objectives 
34 

  
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3. 
STUDY DESIGN 
36 
4. 
ELIGIBILITY CRITERIA 
38 
4.1. 
General criteria required for participation in the main protocol, Prospective 
International Observational Study of Epithelioid Hemangioendothelioma: 
38 
4.2. 
Additional criteria specific for this study, Sub-study 1 
39 
5. 
STUDY ENDPOINTS 
40 
5.1. 
Main end-points 
40 
5.2. 
Secondary end-points 
41 
5.3. 
Exploratory end-points 
41 
5.4. 
Justification for the end-points choice 
41 
6. 
TREATMENT 
43 
7. 
CLINICAL ASSESSMENT AND DATA COLLECTION 
44 
8. 
STATISTICAL CONSIDERATION 
44 
8.1. 
Sample size 
44 
8.2. 
Statistical analyses 
45 
REFERENCES 
51 
APPENDIX 2 
55 
1. 
RATIONALE AND BACKGROUND 
55 
2. 
OBJECTIVES 
56 
2.1. 
Primary objective 
56 
2.2. 
Secondary objectives 
56 
3. 
STUDY DESIGN 
56 
4. 
ELIGIBILITY CRITERIA 
58 
4.1. 
General criteria required for participation in the international prospective study: 
58 
4.2. 
Additional criteria specific for Sub-study 2: 
58 
5. 
STUDY ENDPOINTS 
61 
5.1. 
Patients who discontinued sirolimus for reasons other than progression – Treatment-
free Cohort 
61 
5.2. 
Patients who restart sirolimus for secondary progression – Re-treatment Cohort 
62 
6. 
PATIENTS 
63 
6.1. 
Treatment-Free Cohort 
63 
6.2. 
Re-Treatment Cohort 
64 
7. 
CLINICAL ASSESSMENT, DATA COLLECTION AND TREATMENT 
64 
8 
STATISTICAL CONSIDERATION 
65 
8.1. 
Sample size 
65 
8.2. 
Statistical analyses 
65 
8.3. 
Patients who discontinued sirolimus for reasons other than progression 
66 
8.4. 
Patients who restart sirolimus for secondary progression 
67 
REFERENCES 
70 
APPENDIX 3 
72 
BACKGROUND 
72 

  
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Pain assessment criteria 
73 
Pain intensity assessment 
74 
Analgesic drug assessment 
75 
Pain Assessment Criteria 
76 
Exclusion or Drop-out criteria 
77 
Examples: 
78 
REFERENCES 
80 
APPENDIX 4 
82 
1. RATIONALE AND BACKGROUND 
82 
2. DEFINITION 
83 
3. 
EVALUABLE PATIENTS 
83 
FIGURES 
86 
REFERENCES 
90 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

  
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1. RATIONALE AND BACKGROUND 
 
Epithelioid hemangioendothelioma (EHE) is an ultra-rare (incidence rate < 1/1,000,000 of 
population), translocated, vascular soft tissue sarcoma. It shows a peak of incidence in the 
4th decade of life, and it is more commonly diagnosed in females, with reported disease onset 
during pregnancy1,2. 
Two specific translocations have been identified in EHE, representing an hallmark in 
diagnosis today: the fusion of Transcriptional Co-activator with a PDZ-motif (TAZ) with 
Calmodulin Binding Transcription Activator 1 (CAMTA1) genes (TAZ-CAMTA1) which is 
present in almost 90% of cases, and the fusion of Yes-associated Protein (YAP) and 
Transcription Factor E3 (TFE3) (YAP-TFE3), which can be found in around 10% of the 
patients3,4. YAP and TAZ are well-defined downstream effectors in the Hippo pathway. Forced 
activation of YAP/TAZ is thought to drive EHE and contribute to key aspects of the cancer 
phenotype, including metastasis and fibrosis5. 
EHE most often presents as multifocal or metastatic at diagnosis, with lung, liver and bone 
being the most commonly involved sites. The clinical course ranges from cases naturally 
stable over time to those highly aggressive and rapidly fatal. Pleural effusion, lymph node 
metastases and pathologic features (nuclear pleomorphism, mitotic figures and presence of 
necrosis) have been reported to be associated with a worse outcome, but biological and 
molecular predictors are still lacking6. In particular, there is a subgroup  of EHE presenting 
with serosal involvement, typically associated with chronic mild fever, weight loss, asthenia, 
anorexia, severe disease- related pain, (more responsive to anti- inflammatory pain killers 
than morphine), and dyspnoea which seems to perform very poorly. The biological basis 
sustaining this presentation is completely unknown.  
As of today, there are no reports available in the literature providing a comprehensive 
description of the specific radiological features of EHE, both for primary and metastatic 
disease at different sites, and their potential prognostic role has not been explored. In addition, 

  
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there are no published data to indicate the optimal routine follow-up policy of surgically treated 
EHE patients with localised disease and the routine follow-up schedules differ across 
institutions. The appropriate frequency of imaging in cases suffering from distant metastases 
is also left to be determined. 
Also, the definition of radiological progression and the assessment of treatment response in 
EHE remain a major challenge. The appearance or worsening of serosal effusion, the 
changes in serosal involvement and the limited increase in size over a short-time interval  in 
slow-growing variants are not properly captured by Response Evaluation Criteria for Solid 
Tumor (RECIST) definitions for disease progression. This makes the use of such criteria 
unsatisfactory in this complex disease and could potentially lead to a delay in progression 
recognition and treatment start. Similarly, being frequently observed in EHE under treatment, 
improvement of serosal effusion, reduction in size <30%, and correlation between radiology 
and symptoms should be considered when assessing treatment response. 
Surgery is the mainstay of care in the local setting. Active surveillance can be a reasonable 
strategy for patients with naturally stable or asymptomatic, slowly progressive disease, 
reserving medical treatment to symptomatic or progressive cases7. 
Data on conventional chemotherapy in advanced EHE are limited to case reports and single-
institution experiences and suggest a limited role for the drugs commonly used in adult-type 
soft tissue sarcomas8,10. Signs of activity have been reported with the use of anti-
angiogenics, including pazopanib, sorafenib, bevacizumab, alone or in combination with 
chemotherapy, and apatinib11-14. Due to the unique natural history of the disease, the value 
of antiangiogenics and/or immunomodulatory agents has also been explored, with responses 
described with sirolimus, thalidomide, interferon, and celecoxib15-18. 
In absence of any available active treatment, EHE is a neglected disease, and the 
identification of new potentially active compounds, especially for patients affected by the more 
aggressive EHE variant is critically important. To this end, it is of major importance to identify 

  
Protocol POEM_V6.0 22nd May 2025 
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the mechanism of disease progression, the <inflammatory-like= disease presentation, and the 
prevalence of the disease in young females. 
Several lines of evidence have highlighted the significance of inflammation at the local and/or 
systemic level in human tumor pathobiology. Indeed, inflammation can influence tumor 
progression, metastasis and therapeutic outcome by establishing a tumor supportive immune 
microenvironment. These processes are mediated through a variety of cytokines and 
hormones that exert their biological actions either locally or distantly via systemic circulation. 
Estrogen signaling is mediated via several receptor proteins. In addition to the classical ERα 
and ERβ19, the membrane-bound G-protein coupled estrogen receptor (GPER) mediates both 
the genomic and non-genomic effects of estrogen and has been implicated in the 
development of other tumors such as breast cancer20. Interestingly, GPER stimulation 
activates YAP and TAZ as key effectors of the Hippo pathway21. Insulin-like growth factor-
1(IGF-1) has also been shown to regulate GPER expression and function, suggesting a 
crosstalk between growth factors and ERs22. 
The availability of translatable preclinical models of human EHE, able to properly recapitulate 
tumor biology and response to treatment of the clinical tumors, appears instrumental for the 
development of innovative and effective treatments. Patient-derived xenograft (PDX) models 
preserve the original histomorphological and molecular characteristics of the originating 
clinical tumors. We previously demonstrated the consistency between preclinical data 
obtained on PDXs of different soft-tissue sarcoma histotypes (solitary fibrous tumor, 
epithelioid sarcoma and dedifferentiated liposarcoma) and clinical results concerning the 
activity of several cytotoxic and molecularly targeted drugs, providing novel insight into the 
antitumor effect of different combinations that was instrumental to design novel clinical trials23-
27. 
MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression 
at the post-transcriptional level. Their proven deregulation in several types of human cancer, 

  
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and the possibility to be reliably detected in both tissue and blood specimens, have prompted 
the assessment of miRNAs as novel cancer biomarkers21. No information is currently available 
on miRNA expression and function in EHE. 
 
 
 
 
 
 
 
 

  
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2. RESEARCH OBJECTIVES 
 
2.1. 
Clinical research objectives 
1. To provide a demographic description of the population affected by advanced EHE 
2. To provide a description of clinical presentation, natural history, and treatment 
pattern in patients with advanced EHE.   
3. To provide a description of tumour-related symptoms and their changes over time 
4. To provide a tumor-related pain assessment 
5. To prospectively identify clinical prognostic factors 
6. To describe the radiological features of the disease (group A, B, C, D, E) 
7. To correlate radiologic features with the outcome and the tested plasma levels of the 
cytokines and hormones (group A, B, C, D, E) 
8. To assess radiologic response to systemic treatments by comparing different 
assessment criteria and, in particular, antitumor activity of sirolimus in patients affected 
by progressing EHE (group B, D)  
9. To assess the proportion of patients in groups B and D who experience disease 
progression after discontinuing sirolimus, as well as their outcomes following sirolimus 
discontinuation or potential rechallenge.  
 
2.2. 
Translational research objectives 
 
1. To assess i) the longitudinal profiles of circulating cytokines, hormones, and 
miRNAs, and ii) the ERα, Erβ and GPER expression and the YAP/TAZ activation in 
tumor tissues, according to the clinical course of the disease. To this end the analysis 
will be conducted on  the whole study patient population compared to healthy controls, 
and by stratifying EHE patients who will enter the study in 3 subgroups according to 
disease behavior (non- growing disease, slow- growing disease, highly- aggressive 
disease) 

  
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2. To generate preclinical tumor models (PDXs and cell lines) for comparatively 
assessing the activity of anticancer agents and inform the design of new clinical trials. 
EHE preclinical models will be also used for validating novel therapeutic targets. 
3. To identify and validate novel biomarkers to inform patient management 
(prognosticators and predictors of response to medical agents) as well as potential 
therapeutic targets. 
 
 
3. STUDY DESIGN 
In this observational, prospective study all consecutive patients diagnosed with EHE treated at 
participating centers will be included. We will enroll a minimum number of 150 EHE patients, 
including: 
• Group A: newly diagnosed, advanced (i.e., locally advanced and or metastatic), EHE, 
naturally stable disease on follow-up 
• Group B: newly diagnosed, advanced, EHE with progressive disease requiring systemic 
treatment 
• Group C: previously diagnosed, advanced, EHE already on active surveillance 
• Group D: previously diagnosed, advanced, EHE already on systemic treatment  
• Group E: localized EHE. 
The details of the sub-studies designed to assess clinical research objectives 8 and 9, specifically 
the evaluation of sirolimus’s antitumor activity in patients with progressing EHE and the 
outcomes following sirolimus discontinuation or potential rechallenge, are provided in Appendix 
1 and 2, respectively.  
The stratification according to disease behavior (non-growing disease, slow-growing disease, 
highly- aggressive disease) foreseen by the translational study will be done according to the 
following criteria: 

  
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a) <Non-growing disease=: absence of progressive disease over 12 months. 
b) <Slow-growing disease=: evidence of progressive disease between 6 and 12 months and 
patient belonging to group D (provided that treatment was started in evidence on 
progressive disease). 
c) <Highly- aggressive disease=: evidence of progressive disease within 6 months. 
 
Progressive disease will be defined as: 
c.1. 
Evidence of RECIST 1.1 progression 
c.2. 
Any increase in tumor size of the known lesions (even not meeting RECIST 1.1 
definition of progression) in association with worsening of at least two tumour related 
symptoms (tumour-related pain*, fever, weight loss, asthenia)  
c.3. 
Evidence of progression evaluated by Serosal Changes and Outcomes Reporting 
(RESCORe) criteria and worsening of at least two tumour-related symptoms (tumour- 
related pain*, fever, weight loss, asthenia) 
* Worsening of pain is defined accordingly to Pain Assessment Criteria (Appendix 3) as: at 
least a 30% increase in worst pain intensity (WPI) within the last week with no more than a 
10% reduction in opioid/NSAID daily dose, and/or at least a 30% increase in opioid/NSAID 
daily dose with no more than a 1-point reduction in WPI and/or the development of new 
disease related pain with a WPI more than 4. 
 
3.1. 
Pathological review 
 
A centralized review of the pathological diagnosis will be required for all patients (group A- E) 
entering the study.  
The following data will be recorded: 
• Evidence of nuclear pleomorphism, mitotic figures and presence of necrosis 
• 
Immunohistochemical staining for CAMTA1 

  
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• 
Molecular testing for WWTR1-CAMTA1 and / or YAP-TFE3 
• 
 
3.2. 
Clinical assessments and data collection 
 
3.2.1. Baseline 
 
The following information will be recorded for all patients (group A-E) entering the study at the 
baseline: 
• 
Demographics – patient ID, DOB, gender, data of diagnosis; childbearing potential, use 
of oral contraception or post-menopausal hormonal therapies for female; date of last 
menstrual cycle; history of autoimmune disease, malignancies, allergy, prolonged 
immunosuppressive treatment 
• 
Data on disease extent – single lesion, metastatic multifocal; metastatic multicentric 
• 
Data on staging – evidence of primary disease, lymph nodal metastases, liver 
involvement, lung involvement, bone involvement, other sites of metastatic disease, 
evidence of serosal involvement, evidence of serosal effusion 
• 
Data on treatment – surgery, active surveillance, radiation therapy (site, dose), medical 
treatment (type), other  
• 
Data on symptoms – pain (NRS), weight loss in the last 3 months (%), episodes of 
temperature (>37.5°) in the last 4 weeks, presence of asthenia in the last 4 weeks, 
anorexia in the last 4 weeks, night sweat in the last 4 weeks, and dyspnoea in the last 4 
weeks. 
• 
Pain assessment visit will be performed if a WPI >4 on a scale from 0 to 10 is reported, as 
indicated in <Pain Assessment= (Section 3.2.4). If WPI is less than 4, data regarding pain 
using BPI will be recorded 
• 
Concomitant medications 
• 
Physical examination (including BMI) 
• 
Quality of life assessment by the ESAS-r questionnaire 

  
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The following tests will be performed for all patients (group A-E) at baseline according to standard 
of care: 
• 
Blood tests (complete blood count, AST, ALT, GGT, ALP, total bilirubin, creatinine, BUN, 
sodium, potassium, calcium, PT, PTT, fibrinogen, glycaemia, total cholesterol, LDL, HDL, 
triglycerides, screening for HBV and HCV); plasmatic B- HCG (for female); GDF-15 assay 
• 
Echocardiogram and ECG 
• 
Radiological assessment: CT scan, MRI, bone scan (as clinically indicated) 
• 
Gynaecological assessment: blood tests (FSH, LH, progesterone, estradiol, prolactin), 
clinical assessment, US 
 
3.2.2. Clinical monitoring 
 
Patient on active surveillance (group A and C) will be monitored every 3-4 months for the first 
2 years and every 6 months thereafter as follows: 
• 
Data on symptoms – pain (NRS), weigh loss in the last 3 months (%), episodes of 
temperature (>37.5°) in the last 4 weeks, presence of asthenia in the last 4 weeks, 
anorexia in the last 4 weeks, night sweat in the last 4 weeks, dyspnoea in the last 4 weeks. 
Following Amendment 6 (22/05/2025), pain will be also assessed by disease-specific 
criteria, as described in Appendix 3. 
• 
Pain assessment visit will be performed if a WPI >4 on a scale from 0 to 10 is reported, as 
indicated in <Pain Assessment= paragraph. If WPI is less than 4, data regarding pain using 
BPI will be recorded 
• Total daily dosages of pain medications, including the cumulative dose of rescue pain 
medication used. 
• 
Physical examination – BMI 
• 
Quality of life assessment by the ESAS-r questionnaire 

  
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• 
Blood tests (complete blood count, AST, ALT, GGT, ALP, total bilirubin, creatinine, BUN, 
sodium, potassium, calcium, PT, PTT, fibrinogen, glycaemia, total cholesterol, LDL, HDL, 
triglyceride); plasmatic B-HCG (for female); GDF-15 assay (as clinically indicated) 
• 
Radiological assessment: CT scan, MRI, bone scan (as clinically indicated) 
 
Patient on active treatment (group B and D), including patients receiving sirolimus, will be 
monitored clinically after 2 weeks from treatment start, then every 4 weeks (for the first 3 
months) and every 8 weeks thereafter as follows: 
• 
Data on symptoms – pain (NRS), weight loss in the last 3 months (%), episodes of 
temperature (>37.5°) in the last 4 weeks, presence of asthenia in the last 4 weeks, 
anorexia in the last 4 weeks, night sweat in the last 4 weeks, dyspnoea in the last 4 weeks. 
Following Amendment 6 (22/05/2025), pain will be also assessed by disease-specific 
criteria, as described in Appendix 3. 
• 
Pain assessment visit will be performed if a WPI >4 on a scale from 0 to 10 is reported, 
as indicated in <Pain Assessment= paragraph. If WPI is less than 4, data regarding pain 
using BPI will be recorded 
• 
Total daily dosages of pain medications, including the cumulative dose of rescue pain 
medication used. 
• 
Childbearing potential (females) and length of menstrual cycle (fertile females) 
• Physical examination – BMI 
• 
Quality of life assessment by the ESAS-r questionnaire 
• 
Blood tests (complete blood count, AST, ALT, GGT, ALP, total bilirubin, creatinine, BUN, 
sodium, potassium, calcium, PT, PTT, fibrinogen, glycaemia, total cholesterol, LDL, HDL, 
triglycerides); plasmatic B-HCG (for female); GDF-15 assay (as clinically indicated) 
• Radiological assessment (CT scan, MRI, bone scan as clinically indicated) will be 
performed every 3-4 months. For patients receiving sirolimus, radiological assessments 

  
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will be performed every 12 weeks (+/- 1 week). 
• Gynecological assessment (FSH, LH, progesterone, estradiol, prolactin, clinical 
assessment, US) will be performed every 6-8 months.  
• For patients on sirolimus, sirolimus plasma levels will be monitored after 2 weeks and 4 
weeks from treatment start and every 4 weeks thereafter. Sirolimus plasma level target 
will be g 15 ng/mL.  
• Reason for oncologic treatment discontinuation (e.g. disease progression, unacceptable 
toxicity, patient’s refusal to continue treatment, etc) will be collected.  
 
Patients with localised disease (group E) will be monitored every 3-4 months for the first 2 
years, every 6 months up to year 5 and yearly thereafter, as follows: 
• Data on symptoms – pain (NRS), weight loss in the last 3 months (%), episodes of 
temperature (>37.5°) in the last 4 weeks, presence of asthenia in the last 4 weeks, 
anorexia in the last 4 weeks, night sweat in the last 4 weeks, dyspnoea in the last 4 weeks. 
Following Amendment 6 (22/05/2025), pain will be also assessed by disease-specific 
criteria, as described in Appendix 3. 
• 
Total daily dosages of pain medications, including the cumulative dose of rescue pain medication 
used. 
• Physical examination – BMI 
• Quality of life assessment by the ESAS-r questionnaire 
• 
Blood tests (complete blood count, AST, ALT, GGT, ALP, total bilirubin, creatinine, BUN, 
sodium, potassium, calcium, PT, PTT, fibrinogen, glycaemia, total cholesterol, LDL, HDL, 
triglycerides); plasmatic B-HCG (for female); GDF-15 assay (as clinically indicated) 
• Radiological assessment: CT scan, MRI, bone scan (as clinically indicated) 
 
 

  
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3.2.3. Radiologic assessment 
 
Radiologic images (CT and/or MRI scans) will be uploaded on to the XNAT platform and 
centrally reviewed by a sarcoma dedicated radiologist.  
XNAT is a cross-platform, open-source tool designed to support imaging research. Core 
functions include import, archiving, processing, annotation and secure distribution of imaging 
and related study data.  
The centralized radiological review will 1) describe the radiological features of the disease 
(group A, B, C, D, E), 2) assess response to systemic treatments by RECIST, by CHOI criteria 
and by RESCORe criteria (group B, D), presented in Appendix 4. 
 
3.2.4. Pain assessment 
 
A pain assessment visit will be performed if a WPI >4 on a scale from 0 to 10 is reported. When 
possible, pain assessment will be conducted by a palliative care specialist or a pain therapist. 
Starting from Amendment 6 (22/05/2025), during this evaluation, the clinician will address the 
following aspects: 
• relationship between pain and the disease. If uncertainty exists regarding the pain's 
origin, further investigation with appropriate radiological imaging will be considered; 
• pain characteristics. The presence of nociceptive, neuropathic, and/or nociplastic pain 
will be determined using validated tools (i.e. EAPC/IASP algorithm for neuropathic 
pain28) in order to tailor appropriate therapy; 
• pain intensity. The clinician will access current pain intensity, average pain intensity of 
the last week, and WPI of the last week, using a NRS ranging from 0 to 10 during the 
visit; 
• presence of a pain syndrome. Syndromes will be evaluated according to established 
criteria, such as those defined by the IASP Task Force29. 
If disease-related WPI >4 is present, tumor response to pain treatment will also be evaluated 

  
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with Pain Assessment Criteria (Appendix 3).  
During a pain assessment visit, the reported pain will serve as the reference for evaluating pain 
intensity and its link to the disease. If unavailable, follow-up questionnaire data will be used. 
For patients evaluated before amendment 6, data of pain will be retrospectively retrieved, 
whenever feasible. The primary source will be the pain assessment visit conducted by a 
palliative care specialist and/or a pain therapist that is closest to the oncological visit and/or 
radiological assessment, ensuring that the two assessments are no more than two weeks apart. 
If multiple pain assessment visits are available, priority will be given to the one closest to the 
corresponding oncological or radiological evaluation. If such a visit was not performed within 
the proposed time-frame, pain intensity and characteristics will be extracted from available 
follow-up questionnaires.  
 
3.2.5. Progression 
 
At the time of progression, the following data will be recorded, and the following tests performed 
for all patients (group A-D): 
• 
Data on treatment choice – surgery, active surveillance, radiation therapy (site, dose), 
medical treatment (type), other  
• 
Data on symptoms – pain (NRS), weight loss in the last 3 months (%), episodes of 
temperature (>37.5°) in the last 4 weeks, presence of asthenia in the last 4 weeks, 
anorexia in the last 4 weeks, night sweat in the last 4 weeks, dyspnoea in the last 4weeks. 
• 
Pain assessment visit will be performed if a WPI >4 on a scale from 0 to 10 is reported, as 
indicated in <Pain Assessment= paragraph. If WPI is less than 4, data regarding pain using 
BPI will be recorded 
• Total daily dosages of pain medications, including the cumulative dose of rescue pain 
medication used. 
• 
Physical examination – BMI 

  
Protocol POEM_V6.0 22nd May 2025 
19 
 
• 
Quality of life assessment by the ESAS-r questionnaire 
• 
Blood tests (complete blood count, AST, ALT, GGT, ALP, total bilirubin, creatinine, BUN, 
sodium, potassium, calcium, PT, PTT, fibrinogen, glycaemia, total cholesterol, LDL, HDL, 
triglycerides); plasmatic B-HCG (for female); GDF-15 assay 
• 
Radiological assessment: CT scan, MRI, bone scan (as clinically indicated)  
• 
Gynaecological assessment: blood tests (FSH, LH, progesterone, estradiol, prolactin), 
clinical assessment, US  
 
 
4. STUDY POPULATION  
 
We plan to include at least 150 patients (range: 150-200) in 72 months, followed by a follow-
up  time of 5 years. 
4.1. 
Inclusion criteria 
 
1) 
Histological diagnosis of EHE according to 2020 WHO classification, performed on biopsy 
or surgical specimen 
2) Signed informed consent 
3) Adequate patient compliance to treatment or follow up 
4) No age limits 
 
4.2. 
Exclusion criteria 
 
1) 
Impossibility to ensure adequate compliance 
 
 
 
5. TRANSLATIONAL STUDY 
 
The translational part of the study will be carried out on independent case series, limited to INT, 
Milan, University of Torino (UNITO), and to Institute of Cancer Research (ICR)/Royal Marsden 

  
Protocol POEM_V6.0 22nd May 2025 
20 
 
Hospital (RMH), London: 
 
INT-Milano and UNITO series: overall, blood (plasma and serum) samples from g 50 
molecularly confirmed EHE patients and FFPE tissues from at least 20 molecularly confirmed 
EHE patients among those in which the blood sample is taken will be collected. Blood 
samples will be collected from all consecutive molecularly confirmed EHE patients entering 
INT irrespective of the disease phase (group A-E). In addition to the baseline sample, for 
each patient longitudinal samples will be collected after 1 month from baseline, at 6 months 
and in case of evidence of progression. For patients starting a medical treatment, samples 
will be collected at baseline then after 2 weeks, 1 and 6 months of treatment and in case of 
disease progression. 
Only patients with a pathologic diagnosis of EHE confirmed by the presence of either 
WWTR1- CAMTA1 or YAP-TAZ fusion gene will be considered eligible for these analyses. 
Blood samples from healthy individuals will be also collected for comparative purpose with 
EHE cases; gender and age will also be registered in order to perform adjusted comparative 
analyses. 
For EHE patients undergoing surgical procedures, a tumor sample will be transplanted into 
immune-compromised mice to generate PDXs (Section 5.6). Corresponding cell lines will be 
then established following PDX disaggregation. 
Clinical data of all EHE patients who will enter this study will be collected prospectively in a 
dedicated database, also recording samples for study-related translational research analysis, 
and progressively updated with patient outcome information. 
 
ICR/ RMH - London series: 
Similar to the INT series, blood and tissue samples will be collected from all patients who 
are treated at or are referred to the RMH. The expected number of patients diagnosed with 

  
Protocol POEM_V6.0 22nd May 2025 
21 
 
EHE at RMH is approximately 5-6 patients per year (approx. 18 over the 3-year period). 
Mirroring the blood collection at INT, blood will be collected at the following time points: 
Patients who undergo observation 
• 
Diagnosis (Baseline Pre-treatment) 
• 
Baseline +1month 
• 
Baseline +6months 
• 
Treatment Baseline 
Patients who undergo a systemic therapy 
• 
Treatment Baseline + 2 weeks 
• 
Treatment Baseline + 1 month 
• 
Treatment Baseline + 6 months 
• 
Evidence of disease progression 
RMH will also collect tissue alongside these patient groups including diagnostic FFPE and any 
excess surgical resection tissue (fresh frozen and FFPE). RMH will also collect samples from 
patients who are already being treated at RMH for EHE, to maximize sample numbers. 
All blood and tissue will be stored in the UK’s National EHE Biobank, the setup of which was 
funded by the EHE Rare Cancer Charity, and is situated at The Royal Marsden Hospital 
NHS Foundation Trust in line with HTA regulations and released for analysis when required. 
ICR will also carry out CRISPR whole genome screen on PDX-derived cell lines generated at 
INT to identify new therapeutic targets for the disease. 
The RMH will participate in the outlined research project as a hosted non-commercial study 
and will submit the protocol proposal to the UK regulatory authorities before commencing 
consent and tissue collection. Once the appropriate regulatory approvals are in place, the 
Human Tissue Manager based at RMH, who is part funded by the EHE Rare Cancer Charity, 
will consent any patients to this study and funding for this work is already covered within the 
percentage of funded whole time equivalent. In addition, samples collection can be 
undertaken by the unit’s Biological Specimen Coordinator. 

  
Protocol POEM_V6.0 22nd May 2025 
22 
 
The study will be started on the INT case series (Training set, used for biomarkers discovery) 
and the circulating and/or tissue factors emerging as candidate biomarkers will be 
assessed on the UNITO (Training set) and ICR case series (Testing set) by using the same 
experimental approaches. If results generated in the Training set will identify specific 
biomarkers able to provide useful information for a specific subgroup of patients, the number 
of patients in that group will be enriched. 
Based on an already established collaboration, the top candidates selected in the previous 
steps will be validated on an independent case series (Validation set) collected at MSKCC-
New York. 
 
5.1. 
Circulating cytokines (limited to INT, Milan, UNITO and ICR/ RMH, London) 
 
Cytokines will be initially analysed in plasma samples from EHE patients by using a protein 
array able to simultaneously detect the expression of 105 different cytokines. 
Successively, cytokines differentially expressed between patients and healthy donors, or 
between different groups of patients, will be assessed in the same plasma and serum 
samples using specific ELISA assays and the Elecsys test ® (vitro diagnostic immunoassay). 
Also, pleural and peritoneal effusion can be analyzed, when available. Following Amendment 
6 (20/05/2025), this analysis will be performed only using Elecsys test ® 
 
5.2. 
Circulating hormone profiles (limited to INT, Milan, UNITO, and ICR/RMH, 
London) 
 
Serum concentrations of estradiol, estrone, estriol, progesterone, DHEAS, androstenedione, 
testosterone, dihydrotestosterone, luteinizing hormone, follicle- stimulating hormone, 
prolactin, sex hormone-binding globulin and IGF-1 will be determined by different kinds of 
immunoassays using commercial kits. 
 
5.3. 
Circulating miRNA profiles (limited to INT, Milan, UNITO, and ICR/RMH, London) 

  
Protocol POEM_V6.0 22nd May 2025 
23 
 
 
The expression profiling of plasmatic miRNAs will be carried out by the qRT-PCR-based 
OpenArray Technology (which simultaneously evaluate the expression of 754 different 
miRNAs and 4 control RNAs in replicates). 
 
5.4. 
Multi-omic analysis of EHE clinical samples (limited to INT, Milan, UNITO, and 
ICR/RMH, London) 
 
Comprehensive genomic, transcriptomic and proteomic profiling of FFPE specimens WES 
analysis, RNA-seq analysis, metabolomics profile and mass spectrometry will be undertaken 
(30 samples combined from INT, UNITO and RMH). WES, RNA-seq and metabolomic profile 
will be performed at INT or UNITO. Mass spectrometry will be performed at the ICR using 
established protocols developed in the team. A small subset of tumors (N=4) from INT will 
undergo single-cell RNA-seq analysis and spatial transcriptomic analysis.  
 
5.5. 
Immunohistochemistry 
 
Immunostaining of ERα, phosphoERα, ERβ, GPER, YAP, AR, PR, phosphoYAP, TAZ, 
phosphoTAZ and aromatase will be performed on 5-μm thick FFPE sections using specific 
moAbs and standard immunohistochemical techniques. 
Whenever possible, the expression of ERα, ERβ, AR and PR on PBMCs will be also detected 
by flow-cytometric analysis. 
 
5.6. 
PDX model generation (limited to INT, Milan, and ICR/RMH, London) 
 
Patients who will have surgery at INT will be considered for generation of a patient-derived 
xenograft. PDXs will be obtained by directly implanting freshly resected tumor pieces 
subcutaneously/orthotopically into immune-compromised (nude or SCID) mice and 
characterized for consistency with the originating clinical tumors in terms of histo- 
morphology, presence of specific translocations (WWTR1-CAMTA1 or YAP-TFE3), genomic 

  
Protocol POEM_V6.0 22nd May 2025 
24 
 
and transcriptomic profiles. 
PDX will be then be mechanically or enzymatically disaggregated into single cells to establish 
cell lines. 
 
5.7. 
CRISPR whole genome screen (limited to INT, Milan, and ICR/RMH, London) 
 
A human genome-wide knockout CRIPSR library consisting of 90,709 single guide RNA 
(sgRNA) sequences to target 18,010 human genes, will be used to stably express a single 
sgRNA per cell in a cas9 expressing PDX-derived cell line. 
 
 
6. STATISTICAL ANALYSIS  
 
Descriptive statistics will be used to summarize patient and tumour characteristics. 
Contingency tables will be used to describe the associations between pairs of categorical 
variables. Multivariate association between clinical characteristics, such as symptoms at 
baseline and new symptoms during follow-up, baseline metastatic sites and sites of 
progressive disease, and treatments will be studied by applying cluster analysis, the results of 
which will be represented using heat map plots. The identified patient clusters will be compared 
with the 5 groups A-B-C-D-E defining the EHE diagnosis to better characterize disease 
heterogeneity. 
Overall survival (OS) and progression-free survival (PFS) curves will be estimated with  the 
Kaplan-Meier method in the 5 groups along with survival estimates at predefined endpoints 
(i.e., 6-, 12-, 18-, 24-month). We will also estimate the post- progression OS (ppOS) curves 
for patients who will develop progressive disease. Multivariable prognostic analyses will be 
performed using Cox models; due to the low number of cases and events the analyses will be 
performed by applying penalized likelihood methods. Variable selection will be performed 
beforehand by applying appropriate variable selection procedures within the framework of 

  
Protocol POEM_V6.0 22nd May 2025 
25 
 
Machine Learning algorithms for survival data (e.g. random forest) for inclusion in subsequent 
multivariable Cox models for OS and PFS.  
Duration of response (DoR) will be computed with the Kaplan-Meier method as the difference 
between first assessment of response and disease progression or death whichever occurs 
first.  
For DoR, OS, PFS, and ppOS, in the absence of the specific event of interest, the times will 
be censored at the date of last follow up where the patients were free from the event.  
The details of the sub-studies designed to assess the evaluation of sirolimus’s antitumor 
activity in patients with progressing EHE and the outcomes following sirolimus discontinuation 
or potential rechallenge are provided in Appendix 1 and 2, respectively.  
 
For the translational study, the design and statistical analysis pipeline will be later established 
in detail. In general, the discovery phase will follow a case-control design for binary endpoints 
(e.g. response) and a nested-case control design for survival endpoints (e.g. progression-free 
survival or overall survival). Hence, statistical models taking into account the nature of paired 
data will be applied. To adjust for the sex and age heterogeneity, and other inhomogeneity 
factors between cases and controls we will estimate a propensity score (PS)30, as a balancing 
score, a function of which will be used as weight in all the comparative analyses31. 
Unsupervised analysis of blood tests, cytokines, hormones, miRNA and immunohistochemistry 
data will be performed by applying appropriate methods of cluster analysis, the results of which 
will be represented using heatmap plots. We will also use appropriate Machine Learning 
algorithms for variable selection and model building to integrate multi-omics data into the aim 
of deriving prognostic signatures. To increase the statistical power, analysis of biomarkers will 
be performed comparing patients with higher risk tumors (in this protocol labelled as <Non-
growing disease=):vs lower risk tumors (in this protocol labeled as <Slow-growing disease=:plus 
<Highly- aggressive disease=). 

  
Protocol POEM_V6.0 22nd May 2025 
26 
 
In the validation phases, appropriate analyses will be performed in coherence with the discovery 
phase design. 
The analyses will be carried out using the SAS® and R software. We will consider a statistical 
test as significant when achieving a p value <0.05. 
 
 
7. PROTECTION OF HUMAN SUBJECTS 
 
This study will be conducted in accordance with the principle of World Medical Association 
Declaration of Helsinki, 2008.  
 
 
7.1. 
Independent Ethics Committee (IEC) or Institutional Review Board (IRB) 
Documented approval from the appropriate IEC or IRB will be obtained for all participating 
centers prior to study start. When necessary, an extension, amendment, or renewal of the IEC 
or IRB approval must be obtained and also forwarded to the study initiator, except for changes 
involving only logistical or administrative aspects of the study. 
 
Before documentation of any patient data, informed consent should be given by the patient in 
writing. The investigator must explain to each subject the nature of the study, its purpose, the 
procedures involved, the expected duration, the potential risks and benefits involved, and any 
potential discomfort. Each subject must be informed that participation in the study is voluntary 
and that he/she may withdraw from the study at any time and that withdrawal of consent will not 
affect his/her subsequent medical treatment or relationship with the treating physician.  This 
informed consent should be given by means of a standard written statement, written in 
nontechnical language. The form must be signed and dated by the appropriate parties.  

  
Protocol POEM_V6.0 22nd May 2025 
27 
 
In countries where required by law or regulation, the investigator must have the IEC or IRB’s 
written approval or favorable opinion of the written informed consent form(s) and any other 
written information to be provided to patients prior to the beginning of the observation.  
The original, signed ICF for each subject will be verified by the investigators and kept on file, 
according to local procedure, at the study center.   
 
7.2. 
Management of Patient Data 
 
All investigators will ensure adherence to applicable data privacy protection regulation. All patient 
data will be captured and maintained in a study specific database with password-protected 
access. Data is entered using an assigned study subject identification number. Data or any 
research samples obtained in this study will only be transferred in encoded form and should not 
contain any data which, on its own account or in conjunction with other freely available data, can 
be used to re-identify natural persons. The investigators are obligated to ensure that no 
documents contain such data. The investigator will maintain a list to enable patients’ records to 
be identified in case of queries. All documentation that contains personal health information that 
may include patient identifiable information will be maintained at the site to preserve patient 
confidentiality. 
 
8. QUALITY CONTROL 
 
The study will be organized, conducted, and reported in compliance with the International 
Council for Harmonisation (ICH) Good Clinical Practice (GCP) guidelines and all applicable 
regulations. 
 
 
8.1. 
Data quality 
 
Before study start at each site, the investigators and all study personnel will be sufficiently trained 
on the study. Investigators will have the chance to discuss and develop a common understanding 

  
Protocol POEM_V6.0 22nd May 2025 
28 
 
of the protocol and the eCRF through virtual meeting(s). All data will be recorded in a 
standardized eCRF. After data entry, missing or implausible data will be queried, and the data 
will be validated. A check for multiple documented patients will be done. National and 
international data protection laws will be followed.  
 
8.2. 
Quality review 
 
Before study start at each site, the investigators and all study personnel will be sufficiently trained 
on the study. Investigators will have the chance to discuss and develop a common understanding 
of the protocol and the eCRF through virtual meeting(s).  The investigator has ultimate 
responsibility for the collection and reporting of all clinical, safety and laboratory data entered on 
the CRF. Quality review will be done initially during site training to review procedures to assess 
data accuracy, completeness, consistency, and reliability. During the study, quality reviews will 
be conducted to ensure completeness and plausibility of data, adherence to the protocol, and 
verification with source documents. Detailed measures for quality reviews will be described in 
the Quality Review Plan (QRP).  
 

  
Protocol POEM_V6.0 22nd May 2025 
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of anti-angiogenic treatment options. BMC cancer 2015; 15:402. 
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24) Stacchiotti S, Zuco V, Tortoreto M, et al. Comparative Assessment of Antitumor Effects 
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25) Stacchiotti S, Saponara M, Frapolli R, et al. Patient-derived solitary fibrous tumour 
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this tumour. Eur J Cancer 2017; 76:84-92. 
26) Stacchiotti S, Tortoreto M, Baldi GG, et al. Preclinical and clinical evidence of activity 
of pazopanib in solitary fibrous tumour. Eur J Cancer 2014; 50:3021-8. 
27) Stacchiotti S, Tortoreto M, Bozzi F, et al. Dacarbazine in solitary fibrous tumor: a case 
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APPENDIX 1 
 
SUBSTUDY 1: PROSPECTIVE OBSERVATIONAL STUDY OF EPITHELIOID 
HEMANGIOENDOTHELIOMA PATIENTS TREATED WITH SIROLIMUS  
 
1. RATIONALE AND BACKGROUND 
 
Epithelioid hemangioendothelioma (EHE) is an ultra-rare and distinctive vascular sarcoma, 
with an incidence of 0.038 per 100,000 people per year, a prevalence of fewer than 1 per 
1,000,000, and approximately 180 new cases annually in the European Union (EU) (de Pinieux 
et al., 2021; Lau et al., 2011; Silvia Stacchiotti et al., 2021a). Around 40% of patients are 
diagnosed with metastatic disease, while at least 20% of those initially presenting with 
localized disease experience distant metastasis upon relapse (Blay et al., 2023). Among 
patients with advanced disease, only those with evidence of disease progression and/or 
paraneoplastic symptoms are candidates for systemic therapy (S. Stacchiotti et al., 2021). 
Patients with serosal involvement may experience excruciating pain, often associated with 
common features as part of a complex pain syndrome (as described in Appendix 3). For 
patients with this disease presentation, progression and response to systemic treatments are 
challenging to assess, as they may involve disease modifications not well captured by the 
Response Evaluation Criteria in Solid Tumors (RECIST). These changes include worsening 
or appearance of serosal effusions, thickening of the pleura or peritoneum, and alterations in 
lung parenchyma with mediastinal shift, even in the absence of clear dimensional changes in 
target lesions or appearance of new ones (as described in Appendix 4) (Anna M. Frezza et 
al., 2021; Rosenbaum et al., 2020; Vanzulli,A, 2024).  
For patients with EHE who need a systemic treatment, there are no active drugs among those 
currently approved and available for front-line therapy of soft tissue sarcomas. Indeed, 
doxorubicin, the standard first-line treatment for advanced soft tissue sarcoma – obtained a 
prolonged disease stabilization in less than 30% of advanced EHE patients with a median 

  
Protocol POEM_V6.0 22nd May 2025 
33 
 
progression free survival (PFS) of 5.5 months (Anna M. Frezza et al., 2021). Pazopanib, 
approved for treatment of soft tissue sarcoma from second-line has also showed marginal 
activity with a median PFS of 2.9 months (Anna M. Frezza et al., 2021). Among non-standard 
therapies, sirolimus is considered one of the most effective antitumor agents in the disease 
and is administered worldwide (Gronchi et al., 2021; S. Stacchiotti et al., 2021). Sirolimus is 
used off-label for this indication and current extensive evidence is highly supportive but it is 
limited to retrospective data (S. Stacchiotti et al., 2021). In 2012 a significant response lasting 
16 months in a patient with EHE associated with Maffucci's syndrome was reported (Orbach 
et al., 2022). Another response to sirolimus was noted in a prospective phase 1 trial of this 
agent in advanced solid tumors, with a partial response (PR) observed in an EHE patient 
lasting more than 3 years (Cohen et al., 2012). Subsequently, Stacchiotti et al. reported a 
retrospective series in 2016, comprising 18 patients with advanced, molecularly confirmed, 
and progressive EHE treated with sirolimus within the Italian Rare Cancer Network (Stacchiotti 
et al., 2016). They observed 1 RECIST PR and 12 cases of stable disease (SD), with a median 
progression-free survival (m-PFS) of 12 months. These findings were updated in 2021 in a 
larger cohort (37 advanced and progressive EHE patients), with a RECIST overall response 
rate (ORR) of 4/37 (11%), a m-PFS of 13 months (range 3.7–not estimable), and a 12-month 
progression-free survival rate of 54%, with a median follow-up (m-FU) of 41.5 months 
(interquartile range [IQR] 23.9–56.8 months) (Silvia Stacchiotti et al., 2021b). These data also 
suggested that spontaneous regression and/or spontaneous stabilization are unlikely to occur 
in the advanced setting after evidence of disease progression, indicating that any observed 
stabilization is likely due to treatment. Thirteen patients with advanced EHE treated with 
sirolimus, who had previously shown disease stability but discontinued therapy for reasons 
other than progression, experienced poor outcomes after stopping sirolimus (Giani et al., 
2023). Nine of the 13 patients progressed, 2 died, and only 2 remained progression-free, with 
a median post-progression PFS of 3.02 months (95% CI, 2.2-3.8). However, among six 

  
Protocol POEM_V6.0 22nd May 2025 
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patients who were rechallenged with sirolimus, one died 37 months later, while five remained 
alive; the best response was RECIST stable disease in five patients and progression in one. 
In these pts, at 81.3-months median follow up (IQR: 62.2-143.1), median post-rechallenging 
PFS was unreached. Although limited by small numbers, this study suggests that a subset of 
EHE patients can achieve durable benefit from sirolimus rechallenge, further supporting its 
antitumor effect in EHE (Giani et al., 2024, 2023). The activity of sirolimus in a pediatric 
population with EHE was reported by Engel, who identified retrospectively 4 partial responses 
out of 6 patients (Engel et al., 2020). Lastly, sirolimus's efficacy was confirmed in patients 
through a survey of the EHE global patient community conducted jointly by the EHE Rare 
Cancer Charity (UK) and the EHE Foundation (USA) patient advocacy groups (Robinson et 
al., 2024). 
Since the activity of sirolimus was detected in the disease, sirolimus has only been investigated 
retrospectively in this tumour. This prospective observational study is aimed at prospectively 
confirming the role of sirolimus in advanced and progressive EHE.  
 
 
 
2. OBJECTIVES  
 
2.1. 
Primary objective.  
 
The primary objective of this study is to provide prospective evidence of sirolimus activity in 
progressive EHE by assessing its ability to stabilize the disease and assess the interval without 
progression. 
 
2.2. 
Secondary objectives 
 
In addition, the activity of sirolimus in advanced progressive EHE will be evaluated looking at 
radiologic response. The overall response rate (ORR) and the duration of response (DoR) will 
be determined based on RECIST v1.1. Besides RECIST v1.1, treatment response 

  
Protocol POEM_V6.0 22nd May 2025 
35 
 
assessment according to additional radiological criteria [Response Evaluation by Serosal 
Changes and Outcomes Reporting (RESCORe)] is included as an exploratory objective 
(Appendix 4). Specifically, EHE can show specific patterns of response and disease 
progression that are not detectable by RECIST and are characterized by improvement / 
appearance of serosal effusion, changes in pleural thickening, and increase / reduction of lung 
parenchyma with mediastinal shift, in the absence of changes in target lesions or even 
appearance of new ones according to RECIST. RESCORe criteria (Appendix 4), are intended 
to take these parameters into account and complement RECIST v1.1 in the evaluation of 
progression and response.  
Moreover, EHE can be characterized by tumor-related symptoms such as tumor-related pain 
which can interfere with everyday living and deeply impact quality of life. This is especially true 
for patients with serosal infiltration, which may experience excruciating pain associated with 
common features characterizing a complex pain syndrome (as described in Appendix 3). As 
such, pain evaluation is also incorporated as a secondary objective in the assessment of 
response/disease progression (Appendix 3). Quality of life assessed by EORTC QLQ-C30 and 
ESAS will also be evaluated. 
As a further exploratory endpoint, the predictive value of GDF15 will be evaluated. GDF15 is 
a plasma cytokine produced by EHE cells and is detected in the plasma of patients with EHE 
(Stacchiotti et al., 2024). Indeed, plasma levels of GDF15 were recently shown to predict EHE 
aggressiveness in a retrospective and a prospective cohort, part of the main <Prospective 
International Observational Study on Epithelioid Hemangioendothelioma=. Indeed, patients 
with high-risk disease were characterized by high levels of GDF-15 which may grow at disease 
progression. Preliminary findings suggest that plasma concentration of GDF-15 can be 
modulated during treatment with sirolimus, decreasing even in patients who achieve disease 
stabilization and increasing in patients experiencing disease progression (Stacchiotti et al., 
2024). 

  
Protocol POEM_V6.0 22nd May 2025 
36 
 
 
3. STUDY DESIGN 
 
This is a prospective Sub-study embedded within the <PROSPECTIVE INTERNATIONAL 
OBSERVATIONAL 
STUDY 
ON 
EPITHELIOID 
HAEMANGIOENDOTHELIOMA: 
1/DESCRIBING THE CLINICAL PRESENTATION, NATURAL HISTORY, AND TREATMENT 
OUTCOMES; 2/EVALUATING CYTOKINES AND HORMONES AS BIOMARKERS; 
3/GENERATING PATIENT-DERIVED PRECLINICAL MODELS AS A TOOL TO ASSESS 
THE ACTIVITY OF ANTICANCER AGENTS AND VALIDATE NOVEL THERAPEUTIC 
TARGETS=. This study will analyze the data of patients with advanced and progressive EHE 
who will have started sirolimus after entering the main Prospective International Observational 
Study (i.e. patients in Groups B, D as described on Page 5 of the main protocol) and after the 
approval of Amendment 6. Patients who will have started sirolimus within the main study 
before the activation of Sub-study 1 and those included in the main protocol after reaching the 
target for Sub-study 1  will not be part of this analysis. Patients included in this study will be 
selected according to strict eligibility criteria and within an established study design. 
The present study is designed as a one-arm prospective observational study, mirroring as 
much as possible a single-arm phase II trial in terms of objectives, eligibility criteria, endpoints, 
sample size calculation, treatment administration, follow-up monitoring, and ascertainment of 
endpoints, as discussed in Table 1. 
 
 
Characteristics 
Single Arm Efficacy Phase II 
Trial 
Sub-study 1  
Objective 
Assess sirolimus activity and 
safety using pre-defined 
outcomes in a controlled clinical 
trial setting. 
Assess sirolimus activity using 
pre-defined outcomes and 
performing direct comparison 
using historical controls (see 
<Statistical methods= section). As 
regards safety assessment, see 
comments in =Safety Reporting=.  

  
Protocol POEM_V6.0 22nd May 2025 
37 
 
Study Design 
Interventional. Patients receive 
sirolimus according to a specific 
protocol. 
Non interventional. Sub-study 1  
is a sub study embedded within 
the main Prospective 
Observational Study of EHE, 
which aims to describe all EHE 
patients regardless of the 
disease phase or the treatment 
they are receiving. In this 
context, it is not considered an 
interventional study. In the main 
Prospective Observational Study 
Protocol Sirolimus is 
administered as an off-label 
treatment according to 
institutional clinical practice. Sub-
study 1, as a sub study of this 
main protocol, will focus on 
analyzing those patients who, 
among all those receiving 
sirolimus in the main study, meet 
the predefined eligibility criteria. 
Ethics 
Committee/IRB 
Approval and 
informed consent 
Required. Focus on explaining 
the experimental nature of the 
treatment.   
Required. Focus on describing 
what real-world data will be 
collected and how, as well as 
what kind of translational 
research will be conducted. 
Good Clinical 
Practice (GCP) 
Compliance 
Strict adherence to GCP, 
including monitoring, 
documentation, and protocol 
adherence. 
Must adhere to GCP for 
observational studies, focusing 
on accuracy of data collection. 
Patient Eligibility 
Criteria 
Defined a priori with strict 
inclusion/exclusion criteria. 
Defined a priori with strict 
inclusion/exclusion criteria. 
Sample Size 
Calculation 
Required. Based on statistical 
power to detect a predefined 
sirolimus effect. Input from 
historical controls used for 
sample size calculation. 
Required. Based on statistical 
power to detect a predefined 
sirolimus effect. Input from 
historical controls used for 
sample size calculation.  
Treatment 
Administration 
Specified by the protocol, 
including dosage, schedule, and 
any adjustments. 
Reflects routine clinical practice, 
with data collected on how the 
treatment is administered. 
Data Monitoring 
Strict monitoring by an external 
Data Monitoring Committee to 
ensure safety and protocol 
adherence. 
Data monitoring by internal 
committee, focusing on data 
quality, integrity, and 
completeness. 
Endpoints / 
Outcomes 
Focus on primary efficacy 
endpoints (i.e. Disease-control 
rate and progression-free 
survival within 12 months from 
initiation of sirolimus). 
Focus on primary efficacy 
endpoints (i.e. Disease-control 
rate and progression-free 
survival within 12 months from 
initiation of sirolimus).  

  
Protocol POEM_V6.0 22nd May 2025 
38 
 
Safety Reporting 
Mandatory adverse events (AE) 
reporting to regulatory authorities 
(e.g., serious adverse events, 
SUSARs). 
Required to report serious 
adverse events, SUSARs, as per 
routine clinical practice. 
Statistical 
Analysis Plan 
(SAP) 
Predefined, detailing methods to 
assess efficacy, adjust for 
confounders, and handle missing 
data. 
Predefined, detailing methods to 
assess efficacy, adjust for 
confounders (propensity score 
methods), and handle missing 
data. 
Documentation 
and Audit 
Requirements 
Detailed and comprehensive, 
with high levels of scrutiny during 
audits. 
Detailed and comprehensive, 
with maintenance of accurate 
records and patient data.  
Data Privacy and 
Confidentiality 
High standards due to clinical 
trial regulations (e.g., GDPR, 
HIPAA). 
High standards due to clinical 
trial regulations (e.g., GDPR, 
HIPAA). 
 
 
4. ELIGIBILITY CRITERIA  
 
These will consist of the criteria required for participation in the main protocol (i.e., the 
Prospective International Observational Study of Epithelioid Hemangioendothelioma) plus 
additional criteria specific for this sub-study (i.e., Sub-study 1): 
 
4.1. 
General criteria required for participation in the main protocol, Prospective 
International Observational Study of Epithelioid Hemangioendothelioma: 
 
4.1.1. Inclusion criteria 
 
1. Histological and molecularly confirmed diagnosis of EHE according to 2020 WHO 
classification, performed on biopsy or surgical specimen 
2. Adequate patient compliance to treatment or follow up 
3. Signed informed consent 
 
4.1.2. Exclusion criteria 
 
1. Impossibility to ensure adequate compliance  
 

  
Protocol POEM_V6.0 22nd May 2025 
39 
 
4.2. 
Additional criteria specific for this study, Sub-study 1 
 
4.2.1. Inclusion criteria 
 
1. Age =/>18 years 
2. Initiation of sirolimus following the completion of the consent process for enrollment in 
the observational study.  
3. Advanced disease not amenable to curative resection  
4. Documented baseline evidence of RECIST v1.1 progression within the 12 months 
prior to treatment initiation  
5. Measurable disease by RECIST v1.1 
6. No anticancer chemotherapy or immunotherapy, or any investigational drug therapy 
outside of this trial during or within 4 weeks of study entry. 
7. No radiation therapy within 2 weeks prior to start of sirolimus. Prior palliative 
radiotherapy to non-target metastatic lesion(s) is permitted.  
8. No major surgery within 4 weeks prior to the start of sirolimus. 
 
4.2.2. Exclusion criteria 
 
1. Anticancer chemotherapy or immunotherapy, any investigational drug therapy outside 
of this trial during or within 4 weeks (or 5 half-lives of the drug) of study entry. 
2. Dementia or significantly altered mental status (e.g., psychiatric disorder) that would 
prevent the understanding or rendering of informed consent and compliance with the 
requirements of this study. 
3. Any severe and/or uncontrolled medical conditions that might jeopardize the 
interpretation of the study results.  
4. Immunocompromised patients, e.g., patients who are known to be serologically positive 
for human immunodeficiency virus (HIV). 
5. Active viral hepatitis (HBV or HCV infection). Active hepatitis B virus (HBV) is defined by 
a known positive HBV surface antigen (HBsAg) result. Patients with a past or resolved 

  
Protocol POEM_V6.0 22nd May 2025 
40 
 
HBV infection (defined as the presence of hepatitis B core antibody and absence of 
HBsAg) are eligible. Patients positive for hepatitis C virus (HCV) antibody are eligible 
only if polymerase chain reaction is negative for HCV RNA. 
6. For female subjects of childbearing potential lack of a serum or urine beta-hCG 
pregnancy test within f 7 days prior to initiating sirolimus therapy 
7. Other malignancy unless curatively treated with no evidence of disease for g3 years 
except adequately treated non-melanoma skin cancer, curatively treated in situ cancer 
of the cervix, ductal carcinoma in situ (DCIS), stage 1, grade 1 endometrial carcinoma, 
or other malignancy considered as definitely cured by the investigator. 
8. Any other severe and/or uncontrolled concurrent medical disease that in the opinion of 
the investigator could cause unacceptable safety risks or compromise compliance (e.g. 
impairment of gastrointestinal (GI) function, or GI disease that may significantly alter the 
absorption of the study drugs). 
9. Radiation therapy within 2 weeks prior to sirolimus start. Prior palliative radiotherapy to 
metastatic lesion(s) is permitted, provided it has been completed 2 days prior to study 
enrollment and no clinically significant toxicities are expected (e.g., mucositis, 
esophagitis). Palliative radiation therapy is allowed during sirolimus treatment. 
10. Major surgery within 4 weeks of start of sirolimus. Patients must have recovered from 
wound or directly surgical related complications at time of sirolimus start. 
 
 
5. STUDY ENDPOINTS 
 
5.1. 
Main end-points 
 
• Disease Control Rate (DCR) according to RECIST 1.1 at 12 months from initiation of 
sirolimus. 

  
Protocol POEM_V6.0 22nd May 2025 
41 
 
• Progression-free Survival (PFS) according to RECIST1.1 within 12 months from initiation 
of sirolimus.  
 
5.2. 
Secondary end-points 
 
• Duration of stable disease according to RECIST 1.1 (DSD)  
• Overall response rate (ORR) according to RECIST 1.1 
• Duration of response according to RECIST 1.1 (DoR) 
• Overall survival (OS) 
• Post-progression OS (ppOS) 
• Quality of life changes during treatment according to EORTC QLQ-C30 questionnaire 
and ESAS   
 
5.3. 
Exploratory end-points  
 
• PFS according to RESCORe (Appendix 4) or pain assessment (Appendix 3) 
• Disease Control Rate (DCR) according to RESCORe (Appendix 4) or pain 
assessment criteria (Appendix 3) 
• ORR according to RESCORe (Appendix 4) or pain assessment criteria (Appendix 3) 
• Correlation between sirolimus plasma levels and PFS, DCR and ORR (sirolimus g20 
ng/dL, between 15 and 20 ng/dL and < 15 ng/dL for at least 80% of the measures) 
• Correlation between GDF-15 levels at the predefined timepoints (baseline, first 
disease radiological evaluation, disease progression) and PFS, DCR, and ORR. 
 
5.4. 
Justification for the end-points choice 
 
We choose to consider both DCR and PFS at the fixed time of 12 months as primary endpoints 
for Sub-study 1, as also suggested by EORTC for phase II studies (Van Glabbeke et al., 2002). 
For both the endpoints an observation period of 12 months was considered appropriate to 

  
Protocol POEM_V6.0 22nd May 2025 
42 
 
clearly determine the clinical relevance of disease stabilization in patients with progressive 
EHE. In fact, this timeframe would help to confirm that sirolimus induces clinically meaningful 
stabilization in progressive disease by: 
• Distinguishing between temporary stabilization and more durable responses. 
• Demonstrating that stabilization translates into meaningful outcomes, such as longer 
progression-free intervals. 
In addition to RECIST v1.1, treatment response assessment according to RESCORe criteria 
(Appendix 4) and Pain Assessment Criteria (Appendix 3) is included as an exploratory end-
point. RESCORe criteria are intended to take disease specific parameters into account and 
complement RECIST v1.1 in the evaluation of radiologic progression and response, while Pain 
Assessment Criteria intend to take pain evolution as reference for disease evolution. 
In the retrospective study from the Italian Rare Cancer Network, 38 patients received sirolimus 
for advanced EHE (Silvia Stacchiotti et al., 2021b). In these patients, investigators observed 
a RECIST ORR of 10.8% (16% in patients without serosal effusion, 0% in patients with serosal 
effusion) and a median PFS of 13 months (47.8 and 4.8 months in patients without and with 
serosal effusion, respectively). Given the differences in outcomes observed in patients with 
serosal effusion, in an exploratory analysis, PFS, DCR and ORR will be evaluated both in the 
entire cohort as well as in the two subgroups of patients with and without serosal effusion 
(Silvia Stacchiotti et al., 2021b).  
Pain evaluation is also incorporated as a secondary objective in the assessment of response 
(Appendix 3). Following the initial documentation of a Worst Pain Intensity (WPI) score 
exceeding 4 (on a 0 to 10 scale), a comprehensive assessment by a Palliative Care or Pain 
Specialist will be conducted. During this evaluation, the specialist will assess the pain 
characteristics, explore its association with the underlying disease, and implement a tailored 
analgesic regimen. A baseline Pain Assessment will be scheduled 3 to 7 days after the start 
of an adequate analgesic treatment. To ensure accurate pain evaluation, patients will be 

  
Protocol POEM_V6.0 22nd May 2025 
43 
 
instructed to document WPI, baseline analgesic regimen, and usage of rescue pain medication 
in a structured paper diary every evening. Palliative Care/Pain specialist follow up will be 
performed at least once a month for the first six months to monitor pain progression and 
optimize pain management. These FU may be conducted also via telemedicine, if clinically 
appropriate. After six months, the FU visit should be performed within one week from the 
oncological FU visit. Pain assessment-based evaluations of disease status will be performed 
during the visit nearest to each scheduled radiological assessment (refer to Appendix 4). 
 
As an exploratory endpoint, GDF15 will also be evaluated. GDF15 is a plasma cytokine 
produced by EHE cells, present in the blood of patients with EHE (Stacchiotti et al., 2024). 
GDF-15 analysis will be descriptive and based on recent data showing that plasma levels of 
GDF15 can predict EHE aggressiveness. (Stacchiotti et al., 2024). Results of this study are 
expected to confirm the association between GDF-15 concentration levels and patient risk. 
Additionally, reduction in GDF-15 after treatment of patients with sirolimus will enhance the 
value of this cytokine as predictive of tumor response 
 
 
 
6. TREATMENT  
 
Patients eligible for Sub-study 1 analysis will be those treated with oral sirolimus, at a starting 
dose of 5 mg/day, in accordance with the instructions provided in the technical data sheet and 
consistent with what is presented in the main protocol. Sirolimus blood levels will be regularly 
monitored: at baseline, before starting treatment, 2 weeks after treatment initiation and every 
4 weeks thereafter. Blood levels will also be checked in cases of severe toxicity. Sirolimus 
blood levels should be maintained between 15 and 40 ng/dL, and daily dosing will be adjusted 
accordingly to achieve this range. Treatment with sirolimus will be continued until disease 

  
Protocol POEM_V6.0 22nd May 2025 
44 
 
progression, unacceptable toxicity, or a patient’s refusal to continue treatment. 
 
7. CLINICAL ASSESSMENT AND DATA COLLECTION  
 
In Sub-study 1 the protocol for patients on active treatment in the larger prospective study will 
be followed as described in chapter 3 (page 15 and following) of the main protocol. In 
particular, radiological assessment of all sites of disease by CT scan, and or MRI, and bone 
scan as clinically indicated, will be performed at baseline and every 3 months, thereafter. For 
patients entering this study and still on therapy, particular attention will be given to planning 
and conducting a radiologic disease reassessment at 12 months. 
 
As for what is foreseen in the main protocol, radiologic images (CT and/or MRI scans) will be 
uploaded onto the centralized XNAT platform and centrally reviewed by a dedicated sarcoma 
radiologist. The XNAT Platform is a cross-platform, open-source tool designed to support 
imaging research with its core function to manage the import, archiving, processing, annotation 
and secure distribution of imaging and related study data. The radiological review will assess 
response to systemic treatments by RECIST, and by RESCORe (Appendix 4). 
 
 
 
8. STATISTICAL CONSIDERATION  
 
8.1. 
Sample size 
 
Sample size considerations are based on DCR over a 12-month period. A single-group design 
will be used to test whether DCR proportion for patients receiving sirolimus differs from that of 
a historical control group. The control group comprises 33 patients analyzed in the study by 
Frezza et al. (Anna M. Frezza et al., 2021) who were treated with anthracyclines, formally 
approved as first-line therapy for patients with advanced STS.  From this series we obtained 

  
Protocol POEM_V6.0 22nd May 2025 
45 
 
the estimate of DCR within 12 months of 33% (11 over 33 patients, unpublished data).  
 
Under the following assumptions:  
• 12-month DCR with anthracyclines: 35% (slightly higher than the historical pooled 
estimate of 33%). 
• Increase in 12-month DCR from 35% to 60% with sirolimus, consistent with the DCR 
estimate obtained by Stacchiotti et al. (Stacchiotti et al., 2021), where among 38 
patients with progressive EHE, the best RECIST response was a partial response in 
4 patients and stable disease in 18 patients.  
• Accrual 24 months, follow-up 12 months. 
Based on these assumptions, we calculated that 35 patients would be needed to test the null 
hypothesis H0: DCR = 35% versus H1: DCR ≠ 35% versus H1: DCR ≠ 35%, using a two-
sided, one-sample exact test for proportions with type I error alpha 5%, to detect a difference 
of 25% (from 35% to 60%) with 80% power. 
Sample size and power calculations were performed using PASS 2024, version 24.0.2. 
 
8.2. 
Statistical analyses  
 
The statistical analyses will be carried out using SAS® Studio (version 5.2., SAS Institute, 
Cary, NC) and R software (last available version, R Foundation for Statistical Computing, 
Vienna, Austria). 
Standard descriptive statistics will be calculated to describe the study patients. Means, 
medians, standard deviations and ranges will be computed, as appropriate, to describe the 
distribution of numerical variables; frequencies and percentages will be calculated for the 
categorical variables. Unless otherwise specified, missing data will not be replaced.  
For each endpoint, the analyses will be done using the corresponding evaluable population.  
 

  
Protocol POEM_V6.0 22nd May 2025 
46 
 
8.2.1. Main endpoints  
 
The RECIST 1.1 Disease Control Rate (DCR) point estimate will be calculated as the number 
of patients with CR+PR+SD divided by the total number of treated patients who will be 
evaluable for response by RECIST 1.1; the exact 95% confidence interval will also be 
estimated. A two-sided, one-sample exact test for proportions, with type I error alpha 5%, will 
be used to test the null hypothesis H0: DCR = 35% versus H1: DCR ≠ 35%). 
PFS time will be calculated from the date of sirolimus start to the date of progression according 
to RECIST 1.1 or death from any cause, whichever will occur first; time will be censored at the 
date of the last follow-up for the patients alive and without progression before the study cut-
off.  
One sample log-rank test will be used to test the difference in 12-month PFS between sirolimus 
and the 35% hypothesized in the historical control. Potential historical control series may 
include patients with progressive disease (PD) from the series analyzed by Frezza et al. (Anna 
M. Frezza et al., 2021), and other series available at the centers participating in the PUSH 
consortium. We will strive to apply the same eligibility criteria as Sub-study 1 to these historical 
series of patients. Moreover, a Cox model will be fitted to estimate the hazard ratio (HR) of 
sirolimus vs other historical treatments. To adjust for the bias resulting from the non-random 
assignment of treatments, each patient will be weighted using the inverse of the propensity 
score (PS) for patients receiving sirolimus, or (1-PS) for those receiving other treatments. The 
weights will be stabilized by using the minimum value between PS and (1-PS). PS represents 
the likelihood of receiving sirolimus based on baseline characteristics, and it will be estimated 
beforehand using a multivariable logistic regression model with a binary response (sirolimus 
vs. other treatments), adjusting for the following covariates: patient’s age, serosal effusion 
(present, absent), primary tumor site (visceral vs others), and number of metastatic sites 
(single vs multiple); possible additional covariates will be selected based on clinical 
considerations.  

  
Protocol POEM_V6.0 22nd May 2025 
47 
 
The PFS curve will also be estimated with the Kaplan-Meier method, and summaries of the 
curve will be estimated at specific timepoints of clinical interest, i.e. 6 and 12 months, together 
with the 95% confidence intervals, along with median times and corresponding interquartile 
ranges. 
  
8.2.2. Secondary endpoints 
 
• Duration of SD according to RECIST 1.1 (DSD) will be evaluated for subjects with SD 
as best response as the time between the date of treatment start to the date of 
RECIST 1.1 PD or death from any cause, whichever will occur first; time will be 
censored at the date of the last follow-up for the patients alive and without progression 
before the study cut-off.  
• Overall response rate (ORR) according to RECIST 1.1: point estimate will be 
calculated as the number of patients with CR+PR divided by the total number of 
treated patients evaluable for RECIST 1.1 response; the exact 95% confidence 
interval will also be estimated. 
• Duration of response according to RECIST 1.1 (DoR): evaluation will be based on 
responders only and will be assessed regardless of treatment modifications of any 
kind. DoR time will be calculated from the date of first disease response to the date of 
RECIST PD or death from any cause (in case of patients who die before evidence of 
disease progression); time will be censored at the date of the last follow-up for the 
patients alive before the study cut-off.  
• Overall survival (OS): time will be calculated from the date of sirolimus start to the date 
of death for any cause; time will be censored at the date of the last follow-up for the 
patients alive before the study cut-off.  

  
Protocol POEM_V6.0 22nd May 2025 
48 
 
• Post-progression OS (ppOS): time will be calculated from the date of RECIST 1.1 
progression to the date of death for any cause; time will be censored at the date of 
the last follow-up for the patients alive before the study cut-off. 
• Quality of life changes during treatment according to EORTC QLQ-C30 questionnaire 
and ESAS: for both the questionnaires descriptive analyses will be performed: mean 
and standard deviation at each time will be estimated and, to represent trends over 
time, plots of mean scores will be depicted for patients with and without PFS events, 
and for patients exhibiting and not exhibiting DCR or ORR. 
 
8.2.3. Exploratory end-points  
 
• PFS according to RESCORe criteria (Appendix 4) or Pain Assessment Criteria 
(Appendix 3): time will be calculated from the date of sirolimus start to the date of 
progression or death from any cause, whichever will occur first; time will be censored 
at the date of the last follow-up for the patients alive and without progression before 
Sub-study 1 cut-off. The PFS curve will also be estimated with the Kaplan-Meier 
method, and summaries of the curve will be estimated at specific timepoints of clinical 
interest, i.e. 6 and 12 months, together with the 95% confidence intervals 
• Disease Control Rate (DCR) according to RESCORe criteria (Appendix 4) or Pain 
Assessment Criteria (Appendix 3): point estimate will be calculated as the number of 
patients with CR+PR+SD by RESCORe and Pain Assessment Criteria, respectively, 
divided by the total number of treated patients who will be evaluable for RESCORe 
and Pain Assessment Criteria, respectively; the exact 95% confidence interval will 
also be estimated. 
• ORR according to RESCORe (Appendix 4) or Pain Assessment Criteria (Appendix 3): 
point estimate will be calculated as the number of patients with CR+PR by RESCORe 
and Pain Assessment Criteria, respectively, divided by the total number of patients 

  
Protocol POEM_V6.0 22nd May 2025 
49 
 
treatet with sirolimus who will be evaluable for RESCORe and Pain Assessment 
Criteria, respectively; the exact 95% confidence interval will also be estimated 
• Correlation between PFS, DCR or ORR by RECIST 1.1 and sirolimus plasma levels 
categorized in 3 subgroups (g20 ng/dL, between 15 and 20 ng/dL and < 15 ng/dL for 
at least 80% of the measures): Kaplan-Meier PFS curves will be estimated in the 3 
sirolimus plasma levels subgroups. A 3x2 contingency table will display the 
percentages of patients with DCR or ORR within each of the 3 sirolimus plasma levels 
subgroups. These analyses have exploratory purposes and no statistical testing will 
be performed. 
• Correlation between PFS, DCR or ORR by RECIST 1.1, and GDF-15 levels at the 
predefined timepoints (baseline, first disease radiological evaluation, disease 
progression). Descriptive analyses of GDF-15 time profile using appropriate plots 
(such as line plots and boxplots to show the distribution of values each time point for 
the different stratification groups) and descriptive statistics (such as mean, standard 
deviation, median, interquartile range (IQR), minimum, and maximum values at each 
time point) will be performed stratifying for PFS status (progression or death present 
vs no events), for DCR (CR+PR+SD vs PD) and RECIST response (CR+PR vs 
SD+PD). Moreover, descriptive analyses will be performed to evaluate the changes in 
GDF-15 levels over time relative to baseline values. These analyses will be stratified 
by PFS status, DCR and ORR. For each time point, descriptive statistics will be 
calculated. The results will be visualized using line plots to display mean changes over 
time with their variability (e.g., mean ± standard deviation) and boxplots to show the 
distribution of changes at each time point for the different stratification groups. This 
approach will allow us to assess how GDF-15 levels change over time in relation to 
key clinical outcomes.  

  
Protocol POEM_V6.0 22nd May 2025 
50 
 
• Correlation between PFS, DCR or ORR by RECIST 1.1 and serosal effusion: Kaplan-
Meier PFS curves will be estimated in the 2 subgroups serosal effusion present or 
absent. A 2x2 contingency table will display the percentages of patients with DCR or 
ORR within each of the 2 subgroups. These analyses have exploratory purposes and 
no statistical testing will be performed. 
 
 

  
Protocol POEM_V6.0 22nd May 2025 
51 
 
 
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Engel, E.R., Cournoyer, E., Adams, D.M., Stapleton, S., 2020. A Retrospective Review of the Use of 
Sirolimus for Pediatric Patients With Epithelioid Hemangioendothelioma. J. Pediatr. Hematol. 
Oncol. 42, e826–e829. https://doi.org/10.1097/MPH.0000000000001643 
Frezza, A. M., Napolitano, A., Miceli, R., Badalamenti, G., Brunello, A., Buonomenna, C., Casali, P.G., 
Caraceni, A., Grignani, G., Gronchi, A., Infante, G., Morosi, C., Saita, L., Simeone, N., Zaffaroni, 
N., Vincenzi, B., Stacchiotti, S., 2021. Clinical prognostic factors in advanced epithelioid 
haemangioendothelioma: a retrospective case series analysis within the Italian Rare Cancers 
Network. ESMO Open 6, 100083. https://doi.org/10.1016/j.esmoop.2021.100083 

  
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Frezza, Anna M., Ravi, V., Lo Vullo, S., Vincenzi, B., Tolomeo, F., Chen, T.W.-W., Teterycz, P., Baldi, 
G.G., Italiano, A., Penel, N., Brunello, A., Duffaud, F., Hindi, N., Iwata, S., Smrke, A., Fedenko, 
A., Gelderblom, H., Van Der Graaf, W., Vozy, A., Connolly, E., Grassi, M., Benjamin, R.S., Broto, 
J.-M., Grignani, G., Jones, R.L., Kawai, A., Tysarowski, A., Mariani, L., Casali, P.G., Stacchiotti, 
S., 2021. Systemic therapies in advanced epithelioid haemangioendothelioma: A retrospective 
international case series from the World Sarcoma Network and a review of literature. Cancer Med. 
10, 2645–2659. https://doi.org/10.1002/cam4.3807 
Giani, C., Dimino, A., Miceli, R., 2024. Patients with advanced epithelioid hemangioendothelioma treated 
with sirolimus: outcome following sirolimus discontinuation. Presented at the Connective Tissue 
Oncology Society Annual Conference. 
Giani, C., Miceli, R., Baldi, G.G., Brunello, A., Vincenzi, B., Morosi, C., Greco, F.G., Gronchi, A., Ingrosso, 
M., Frezza, A.M., Casali, P.G., Ljevar, S., Stacchiotti, S., 2023. Outcome of patients (PTS) with 
advanced epithelioid hemangioendothelioma (EHE) after failure on sirolimus (S). J. Clin. Oncol. 
https://doi.org/10.1200/JCO.2023.41.16_suppl.11574 
Gronchi, A., Miah, A.B., Dei Tos, A.P., Abecassis, N., Bajpai, J., Bauer, S., Biagini, R., Bielack, S., Blay, 
J.Y., Bolle, S., Bonvalot, S., Boukovinas, I., Bovee, J.V.M.G., Boye, K., Brennan, B., Brodowicz, 
T., Buonadonna, A., De Álava, E., Del Muro, X.G., Dufresne, A., Eriksson, M., Fagioli, F., 
Fedenko, A., Ferraresi, V., Ferrari, A., Frezza, A.M., Gasperoni, S., Gelderblom, H., Gouin, F., 
Grignani, G., Haas, R., Hassan, A.B., Hecker-Nolting, S., Hindi, N., Hohenberger, P., Joensuu, 
H., Jones, R.L., Jungels, C., Jutte, P., Kager, L., Kasper, B., Kawai, A., Kopeckova, K., Krákorová, 
D.A., Le Cesne, A., Le Grange, F., Legius, E., Leithner, A., Lopez-Pousa, A., Martin-Broto, J., 
Merimsky, O., Messiou, C., Mir, O., Montemurro, M., Morland, B., Morosi, C., Palmerini, E., 
Pantaleo, M.A., Piana, R., Piperno-Neumann, S., Reichardt, P., Rutkowski, P., Safwat, A.A., 
Sangalli, C., Sbaraglia, M., Scheipl, S., Schöffski, P., Sleijfer, S., Strauss, D., Strauss, S., Sundby 
Hall, K., Trama, A., Unk, M., van de Sande, M. a. J., van der Graaf, W.T.A., van Houdt, W.J., 
Frebourg, T., Casali, P.G., Stacchiotti, S., ESMO Guidelines Committee, EURACAN and 
GENTURIS. Electronic address: clinicalguidelines@esmo.org, 2021. Soft tissue and visceral 
sarcomas: ESMO-EURACAN-GENTURIS Clinical Practice Guidelines for diagnosis, treatment 
and 
follow-up☆. 
Ann. 
Oncol. 
Off. 
J. 
Eur. 
Soc. 
Med. 
Oncol. 
32, 
1348–1365. 
https://doi.org/10.1016/j.annonc.2021.07.006 
Lau, K., Massad, M., Pollak, C., Rubin, C., Yeh, Joannie, Wang, J., Edelman, G., Yeh, Jenny, Prasad, 
S., Weinberg, G., 2011. Clinical patterns and outcome in epithelioid hemangioendothelioma with 
or without pulmonary involvement: insights from an internet registry in the study of a rare cancer. 
Chest 140, 1312–1318. https://doi.org/10.1378/chest.11-0039 
Orbach, D., Van Noesel, M.M., Brennan, B., Corradini, N., Alaggio, R., Ben Arush, M., Schoot, R.A., 
Berlanga, P., Zanetti, I., Hjalgrim, L.L., Di Corti, F., Ramirez, G., Casanova, M., Ferrari, A., 2022. 
Epithelioid hemangioendothelioma in children: The European Pediatric Soft Tissue Sarcoma 
Study Group experience. Pediatr. Blood Cancer 69, e29882. https://doi.org/10.1002/pbc.29882 

  
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Robinson, D., Leonard, H., Baldi, G.G., Tap, W.D., Jones, R.L., Stacchiotti, S., Pantziarka, P., 2024. The 
patient perspective on sirolimus for epithelioid hemangioendothelioma (EHE): results of a 
community survey highlighting the importance of equitable access to treatments. Front. Oncol. 
14, 1367237. https://doi.org/10.3389/fonc.2024.1367237 
Rosenbaum, E., Jadeja, B., Xu, B., Zhang, L., Agaram, N.P., Travis, W., Singer, S., Tap, W.D., 
Antonescu, C.R., 2020. Prognostic stratification of clinical and molecular epithelioid 
hemangioendothelioma subsets. Mod. Pathol. Off. J. U. S. Can. Acad. Pathol. Inc 33, 591–602. 
https://doi.org/10.1038/s41379-019-0368-8 
Stacchiotti, Silvia, Frezza, A.M., Blay, J.Y., Baldini, E.H., Bonvalot, S., Bovée, J.V.M.G., Callegaro, D., 
Casali, P.G., Chiang, R.R.C. ju, Demetri, G.D., Demicco, E.G., Desai, J., Eriksson, M., 
Gelderblom, H., George, S., Gounder, M.M., Gronchi, A., Gupta, A., Haas, R.L., Hayes-Jardon, 
A., Hohenberger, P., Jones, K.B., Jones, R.L., Kasper, B., Kawai, A., Kirsch, D.G., Kleinerman, 
E.S., Le Cesne, A., Lim, J., Chirlaque López, M.D., Maestro, R., Marcos-Gragera, R., Martin 
Broto, J., Matsuda, T., Mir, O., Patel, S.R., Raut, C.P., Razak, A.R.A., Reed, D.R., Rutkowski, P., 
Sanfilippo, R.G., Sbaraglia, M., Schaefer, I.M., Strauss, D.C., Sundby Hall, K., Tap, W.D., 
Thomas, D.M., van der Graaf, W.T.A., van Houdt, W.J., Visser, O., von Mehren, M., Wagner, A.J., 
Wilky, B.A., Won, Y.J., Fletcher, C.D.M., Dei Tos, A.P., Trama, A., 2021a. Ultra-rare sarcomas: A 
consensus paper from the Connective Tissue Oncology Society community of experts on the 
incidence 
threshold 
and 
the 
list 
of 
entities. 
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127, 
2934–2942. 
https://doi.org/10.1002/cncr.33618 
Stacchiotti, S., Martini, S., Pasquali, S., Frezza, A.M., Beretta, A., Percio, S., Lecchi, M., Tortoreto, M., 
Barisella, M., Collini, P., Dagrada, G., Huang, P.H., Jones, R.J., Tap, W., Ingrosso, M., Morosi, 
C., Brich, S., Giani, C., Verderio, P., Casali, P.G., Leonard, H., Gronchi, A., Zuco, V., Zaffaroni, 
N., 2024. GDF-15 is a biomarker of aggressiveness and is down-regulated by the mTOR inhibitor 
sirolimus through ATF4 and ATF5 suppression in epithelioid hemangioendothelioma. Clin. Cancer 
Res. In Press. 
Stacchiotti, S., Miah, A.B., Frezza, A.M., Messiou, C., Morosi, C., Caraceni, A., Antonescu, C.R., Bajpai, 
J., Baldini, E., Bauer, S., Biagini, R., Bielack, S., Blay, J.Y., Bonvalot, S., Boukovinas, I., Bovee, 
J.V.M.G., Boye, K., Brodowicz, T., Callegaro, D., De Alava, E., Deoras-Sutliff, M., Dufresne, A., 
Eriksson, M., Errani, C., Fedenko, A., Ferraresi, V., Ferrari, A., Fletcher, C.D.M., Garcia Del Muro, 
X., Gelderblom, H., Gladdy, R.A., Gouin, F., Grignani, G., Gutkovich, J., Haas, R., Hindi, N., 
Hohenberger, P., Huang, P., Joensuu, H., Jones, R.L., Jungels, C., Kasper, B., Kawai, A., Le 
Cesne, A., Le Grange, F., Leithner, A., Leonard, H., Lopez Pousa, A., Martin Broto, J., Merimsky, 
O., Merriam, P., Miceli, R., Mir, O., Molinari, M., Montemurro, M., Oldani, G., Palmerini, E., 
Pantaleo, M.A., Patel, S., Piperno-Neumann, S., Raut, C.P., Ravi, V., Razak, A.R.A., Reichardt, 
P., Rubin, B.P., Rutkowski, P., Safwat, A.A., Sangalli, C., Sapisochin, G., Sbaraglia, M., Scheipl, 
S., Schöffski, P., Strauss, D., Strauss, S.J., Sundby Hall, K., Tap, W.D., Trama, A., Tweddle, A., 
van der Graaf, W.T.A., Van De Sande, M. a. J., Van Houdt, W., van Oortmerssen, G., Wagner, 

  
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A.J., Wartenberg, M., Wood, J., Zaffaroni, N., Zimmermann, C., Casali, P.G., Dei Tos, A.P., 
Gronchi, A., 2021. Epithelioid hemangioendothelioma, an ultra-rare cancer: a consensus paper 
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the 
community 
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100170. 
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Stacchiotti, S., Provenzano, S., Dagrada, G., Negri, T., Brich, S., Basso, U., Brunello, A., Grosso, F., 
Galli, L., Palassini, E., Libertini, M., Colia, V., Gronchi, A., Dei Tos, A.P., Crippa, F., Morosi, C., 
Pilotti, S., Casali, P.G., 2016. Sirolimus in Advanced Epithelioid Hemangioendothelioma: A 
Retrospective Case-Series Analysis from the Italian Rare Cancer Network Database. Ann. Surg. 
Oncol. 23, 2735–2744. 
Stacchiotti, Silvia, Simeone, N., Lo Vullo, S., Baldi, G.G., Brunello, A., Vincenzi, B., Palassini, E., 
Dagrada, G., Collini, P., Morosi, C., Greco, F.G., Sbaraglia, M., Dei Tos, A.P., Mariani, L., Frezza, 
A.M., Casali, P.G., 2021b. Activity of sirolimus in patients with progressive epithelioid 
hemangioendothelioma: A case-series analysis within the Italian Rare Cancer Network. Cancer 
127, 569–576. https://doi.org/10.1002/cncr.33247 
Van Glabbeke, M., Verweij, J., Judson, I., Nielsen, O.S., EORTC Soft Tissue and Bone Sarcoma Group, 
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Vanzulli,A, 2024. Redefining radiologic responses in epithelioid hemangioendothelioma: beyond 
RECIST? Presented at the CTOS Annual Meeting 2024. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

  
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APPENDIX 2 
 
SUB-STUDY 2: A PROSPECTIVE OBSERVATIONAL STUDY OF EPITHELIOID 
HEMANGIOENDOTHELIOMA PATIENTS TREATED WITH SIROLIMUS AND 
DISCONTINUING SIROLIMUS FOR ANY REASON OTHER THAN DISEASE 
PROGRESSION  
 
1. RATIONALE AND BACKGROUND  
Sirolimus is considered one of the most effective antitumor agents for epithelioid 
hemangioendothelioma (EHE) and is administered worldwide (Gronchi et al., 2021; S. Stacchiotti 
et al., 2021). Sirolimus is used off-label for this indication and current supporting evidence is 
limited to retrospective data.  
 
In 2021, Stacchiotti et al. presented a retrospective series of 37 patients with progressive EHE 
showing a RECIST overall response rate (ORR) of 11%, a m-PFS of 13 months, and a 12-month 
PFS rate of 54%, with a median follow-up of 41.5 months (Silvia Stacchiotti et al., 2021). Thirteen 
patients with advanced EHE treated with sirolimus, who had previously shown disease stability 
but discontinued therapy for reasons other than progression, experienced poor outcomes after 
stopping sirolimus (Giani et al., 2024, 2023). Nine of the 13 patients progressed, 2 died, and only 
2 remained progression-free, with a median post-progression PFS of 3.02 months (95% CI, 2.2-
3.8). However, among six patients who were rechallenged with sirolimus, one died 37 months 
later, while five remained alive; the best response was RECIST stable disease in five patients 
and progression in one. In these patients, at 81.3-months median follow up (IQR: 62.2-143.1), 
median post-rechallenging PFS was unreached. Although limited by small numbers, this study 
suggests that a subset of EHE patients can achieve durable benefit from sirolimus rechallenge, 
further supporting its antitumor effect in EHE.  
 

  
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Disease progression after stabilization/response on sirolimus treatment would be a strong 
indication that previous disease stabilization cannot be reasonably attributed to the natural 
history/indolence of the tumour but to the activity of sirolimus. This will allow prospective 
observation of disease behaviour following sirolimus discontinuation.   
 
 
2. OBJECTIVES 
 
2.1. 
Primary objective 
 
The primary aim of Sub-study 2 is to allow prospective observation of disease behaviour 
following sirolimus discontinuation for any reason other than evidence of disease progression. 
The aim is to prospectively demonstrate, albeit indirectly, that after disease stabilization during 
sirolimus treatment, disease progression resumes upon discontinuation, thus indicating that the 
previous disease stabilization was not due to the natural history/indolence of the tumour but to 
the drug's activity.  
 
2.2. 
Secondary objectives  
 
To allow prospective observation of disease behaviour following sirolimus re-challenge for those 
patients restarting the drug at disease progression. This latter occurrence would be another 
strong indication that the previous disease stabilization was not due to the natural 
history/indolence of the tumour but to the activity of sirolimus.  
 
 
3. STUDY DESIGN  
 
This is a prospective study embedded within the <PROSPECTIVE INTERNATIONAL 
OBSERVATIONAL 
STUDY 
ON 
EPITHELIOID 
HAEMANGIOENDOTHELIOMA: 
1/DESCRIBING THE CLINICAL PRESENTATION, NATURAL HISTORY, AND TREATMENT 
OUTCOMES; 2/EVALUATING CYTOKINES AND HORMONES AS BIOMARKERS; 

  
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3/GENERATING PATIENT-DERIVED PRECLINICAL MODELS AS A TOOL TO ASSESS 
THE ACTIVITY OF ANTICANCER AGENTS AND VALIDATE NOVEL THERAPEUTIC 
TARGETS=. This study will analyse the data of all evaluable patients affected by advanced 
EHE who will discontinue sirolimus for any reason other than evidence of disease progression 
(Treatment-free Cohort), and patients affected by advanced EHE who will re-challenge 
sirolimus for the evidence of disease progression following sirolimus discontinuation (Re-
Treatment Cohort), after entering the main Prospective International Observational Study (i.e. 
patients in Groups B and D as described on Page 5 of the main protocol) and following the 
approval of Amendment 6  Patients who will have discontinue or re-challenge sirolimus within 
the main study before the activation of Sub-study 2 and those included in the main protocol 
after reaching the target for Sub-study 2 will not be part of this analysis. Sub-study 2 will 
consider only patients who discontinue sirolimus for whatever reason (e.g., patient request, 
physician choice, toxicity, others) provided that the patient has had: 
• a sirolimus treatment duration of at least 6 months; and   
• radiological/clinical evidence of disease stability/response at the time of stopping 
sirolimus (i.e., a subset of patients in Group B and D, as described on Page 5 of the 
main protocol).  
 
 
 
 
 
 
 

  
Protocol POEM_V6.0 22nd May 2025 
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4. ELIGIBILITY CRITERIA  
 
These will consist of general criteria required for participation in the international prospective 
study (4,1) and additional criteria specific for Sub-study 2 (4.2):  
 
4.1. 
General criteria required for participation in the international prospective 
study:  
 
4.1.1. Inclusion criteria 
 
1. Histological and molecularly confirmed diagnosis of EHE according to 2020 WHO 
classification, performed on biopsy or surgical specimen  
2. Signed informed consent  
3. Adequate patient compliance to treatment or follow up  
 
4.1.2. Exclusion criteria 
 
1. Impossibility to ensure adequate compliance 
 
4.2. 
Additional criteria specific for Sub-study 2: 
 
4.2.1. Patients who discontinue sirolimus – Treatment-free Cohort 
 
4.2.1.1. 
Inclusion criteria 
 
1. Age =/>18 years 
2. Treatment with sirolimus for at least 6 months at the time of discontinuation  
3. No evidence of disease progression by RECIST v1.1 (i.e., confirmed RECIST stable 
disease or response) at the time of sirolimus discontinuation or within 4 weeks prior to 
sirolimus discontinuation   
4. No anticancer chemotherapy, immunotherapy, or any investigational drug therapy 
following the discontinuation of sirolimus  
 

  
Protocol POEM_V6.0 22nd May 2025 
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4.2.1.2. 
Exclusion criteria 
 
1. Anticancer chemotherapy or immunotherapy or any investigational drug therapy 
concomitant to sirolimus or after sirolimus discontinuation  
2. Dementia or significantly altered mental status (e.g., psychiatric disorder) that would 
prevent the understanding or rendering of informed consent and compliance with the 
requirements of this study. 
3. Any severe and/or uncontrolled medical conditions that might jeopardize the 
interpretation of the study results.  
4. Immunocompromised patients, e.g., patients who are known to be serologically 
positive for human immunodeficiency virus (HIV). 
5. Active viral hepatitis (HBV or HCV infection). Active hepatitis B virus (HBV) is defined 
by a known positive HBV surface antigen (HBsAg) result. Patients with a past or 
resolved HBV infection (defined as the presence of hepatitis B core antibody and 
absence of HBsAg) are eligible. Patients positive for hepatitis C virus (HCV) antibody 
are eligible only if polymerase chain reaction is negative for HCV RNA. 
6. Other malignancy unless curatively treated with no evidence of disease for g3 years 
except adequately treated non-melanoma skin cancer, curatively treated in situ cancer 
of the cervix, ductal carcinoma in situ (DCIS), stage 1, grade 1 endometrial carcinoma, 
or other malignancy considered as definitely cured by the investigator. 
7. Any other severe and/or uncontrolled concurrent medical disease that in the opinion 
of the investigator could cause unacceptable safety risks or compromise compliance 
with the protocol (e.g. impairment of gastrointestinal (GI) function, or GI disease that 
may significantly alter the absorption of the study drugs). 

  
Protocol POEM_V6.0 22nd May 2025 
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8. Radiation therapy concomitant to sirolimus or after sirolimus discontinuation.  
 
4.2.2. Patients who re-challenge sirolimus – Re-treatment Cohort 
 
4.2.2.1. 
Inclusion criteria 
 
1. Age =/>18 years 
2. Evidence of disease progression by Response Evaluation Criteria In Solid Tumors 
(RECIST) v1.1 or by Serosal Changes and Outcomes Reporting (RESCORe) at the time 
of sirolimus rechallenge  
3. After sirolimus rechallenge regular radiologic assessment at least every 3-4 months until 
evidence of RECIST 1.1 progression or sirolimus definitive discontinuation  
4. No anticancer chemotherapy, immunotherapy, or any investigational drug therapy 
following the discontinuation of sirolimus  
 
4.2.2.2. 
Exclusion criteria 
1. Anticancer chemotherapy or immunotherapy or any investigational drug therapy 
concomitant to sirolimus or after sirolimus rechallenge  
2. Dementia or significantly altered mental status (e.g., psychiatric disorder) that would 
prevent the understanding or rendering of informed consent and compliance with the 
requirements of this study. 
3. Any severe and/or uncontrolled medical conditions that might jeopardize the 
interpretation of the study results.  
4. Immunocompromised patients, e.g., patients who are known to be serologically 
positive for human immunodeficiency virus (HIV). 

  
Protocol POEM_V6.0 22nd May 2025 
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5. Active viral hepatitis (HBV or HCV infection). Active hepatitis B virus (HBV) is defined 
by a known positive HBV surface antigen (HBsAg) result. Patients with a past or 
resolved HBV infection (defined as the presence of hepatitis B core antibody and 
absence of HBsAg) are eligible. Patients positive for hepatitis C virus (HCV) antibody 
are eligible only if polymerase chain reaction is negative for HCV RNA. 
6. Other malignancy unless curatively treated with no evidence of disease for g3 years 
except adequately treated non-melanoma skin cancer, curatively treated in situ cancer 
of the cervix, ductal carcinoma in situ (DCIS), stage 1, grade 1 endometrial carcinoma, 
or other malignancy considered as definitely cured by the investigator. 
7. Any other severe and/or uncontrolled concurrent medical disease that in the opinion 
of the investigator could cause unacceptable safety risks or compromise compliance 
with the protocol (e.g. impairment of gastrointestinal (GI) function, or GI disease that 
may significantly alter the absorption of the study drugs). 
8. Radiation therapy concomitant to sirolimus or after sirolimus rechallange.  
 
 
 
5. STUDY ENDPOINTS  
 
5.1. 
Patients who discontinued sirolimus for reasons other than progression – 
Treatment-free Cohort 
 
5.1.1. Main end-point 
 
Progression-free Survival (PFS-1) according to RECIST1.1 from sirolimus discontinuation.   
 
5.1.2. Secondary end-points 
 
• ORR according to RECIST 1.1  

  
Protocol POEM_V6.0 22nd May 2025 
62 
 
• Post-discontinuation OS (pdOS) 
• Quality of life changes during treatment according to EORTC QLQ-C30 questionnaire 
and ESAS. 
 
5.1.3.  Exploratory end-points  
 
• PFS-1 according to RESCORe (Appendix 4) and pain progression (Appendix 3)  
following sirolimus discontinuation  
• Correlation between GDF-15 levels at predefined timepoints (baseline at the time of 
sirolimus discontinuation, at first disease radiological evaluation following sirolimus 
discontinuation, at first evidence of RECIST disease progression following sirolimus 
discontinuation) and PFS-1 according to RECIST 1.1 and pdOS 
• Correlation between serosal effusion and PFS-1 according to RECIST 1.1 and pdOS. 
 
5.2. 
 Patients who restart sirolimus for secondary progression – Re-treatment 
Cohort 
 
5.2.1. Main end-point 
 
Progression-free Survival (PFS-2) according to RECIST 1.1, after sirolimus re-challenge.   
 
5.2.2. Secondary endpoints  
 
• ORR according to RECIST 1.1 
• Duration of response according to RECIST 1.1 (DoR)  
• Post-sirolimus rechallenge OS (psrOS) 

  
Protocol POEM_V6.0 22nd May 2025 
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• Quality of life changes during treatment according to EORTC QLQ-C30 questionnaire 
and ESAS  
 
5.2.3. Exploratory end-points  
 
• ORR by RESCORe (Appendix 4) and pain changes (Appendix 3) 
• PFS-2 by RESCORe (Appendix 4) and pain changes (Appendix 3) 
• Correlation between GDF-15 levels at predefined timepoints (at baseline prior to 
sirolimus rechallenge, at first disease radiological evaluation following sirolimus 
restart, at first evidence of RECIST best response, at first evidence of disease 
progression and at the time of sirolimus definitive interruption) and PFS-2 according 
to RECIST 1.1 and psrOS. 
 
6. PATIENTS 
 
Subjects will be analyzed according to their cohort (Patients who discontinue sirolimus – 
Treatment-Free Cohort; Patients who re-challenge sirolimus – Re-Treatment Cohort).  
 
6.1. 
Treatment-Free Cohort 
 
The Evaluable Analysis Set (EAS) will include all subjects who, after entering Sub-study 2: 
1. Have 
undergone 
a 
baseline 
radiological 
assessment 
following 
sirolimus 
discontinuation, including CT scans, MRI, and bone scans as clinically indicated for 
all sites of disease. 
2. Undergo regular radiological assessments of all disease sites every 3–4 months 
thereafter, until evidence of disease progression or death and/or have at least 3 
radiological assessment following the baseline. 

  
Protocol POEM_V6.0 22nd May 2025 
64 
 
6.2. 
Re-Treatment Cohort 
 
The EAS will include all subjects who, after entering Sub-study 2, re-start sirolimus and: 
1. Have undergone a baseline radiological assessment before sirolimus re-challenge, 
including CT scans, MRI, and bone scans as clinically indicated for all sites of disease. 
2. Undergo regular radiological assessments of all disease sites every 3–4 months 
thereafter, until evidence of disease progression or death and/or have at least 3 
radiological assessment following the baseline 
3. Have restarted oral sirolimus at the daily dose of 5 mg (as for the instructions provided 
in the technical data sheet and consistent with what is presented in the main protocol). 
4. Sirolimus blood levels have been regularly monitored: at baseline, before starting 
treatment, 2 weeks after treatment initiation and every 4 – 8 weeks thereafter and 
have been maintained between 15 and 40 ng/dL, by adjusting the daily intake of the 
drug accordingly to achieve this range.  
 
7. CLINICAL ASSESSMENT, DATA COLLECTION AND TREATMENT 
 
As for what is foreseen in the main protocol, radiologic images (CT and/or MRI scans) will be 
uploaded onto the centralized XNAT platform and centrally reviewed by a dedicated sarcoma 
radiologist. The XNAT Platform is a cross-platform, open-source tool designed to support 
imaging research with its core function to manage the import, archiving, processing, annotation 
and secure distribution of imaging and related study data. The radiological review will assess 
response to systemic treatments by RECIST, and by RESCORe (Appendix 4). 
 
In Re-Treatment Cohort, sirolimus will be started after baseline assessment of all sites of 
disease by CT scan and / or MRI and/or bone scan as clinically indicated performed within 4 
weeks from the first dose of the drug. Sirolimus will be initiated at the daily dose of 5 mg, 

  
Protocol POEM_V6.0 22nd May 2025 
65 
 
according to the instructions provided in the technical data sheet and consistent with what is 
presented in the main protocol. Sirolimus will be continued until disease progression, 
unacceptable toxicity, or a patient’s refusal to continue treatment. 
 
Pain and QoL evaluation will be performed at the baseline, and at least at the same timepoints 
of the radiological assessments, according to Pain Assessment Criteria (Appendix 3).  
 
 
 
8 STATISTICAL CONSIDERATION   
 
8.1. 
Sample size  
 
An observational single-group prospective design will be applied, including those patients who 
will discontinue sirolimus for any reason other than disease progression. To detect a one-year 
PFS-1 of 50% vs 20% in the historical control group (Giani et al., 2024, 2023) at one-sample 
log-rank test with 5% Type I error (two-sided) under the assumption of exponential distribution 
of PFS times, a sample size of 15 patients will allow us to achieve a power of 82.6%.  
 
8.2. 
Statistical analyses  
 
The statistical analyses will be carried out using SAS® Studio (version 5.2., SAS Institute, 
Cary, NC) and R software (last available version, R Foundation for Statistical Computing, 
Vienna, Austria).  
 
Standard descriptive statistics will be calculated to describe the study patients: Means, 
medians, standard deviations and ranges will be computed, as appropriate, to describe the 
distribution of numerical variables; frequencies and percentages will be calculated for the 
categorical variables. Unless otherwise specified, missing data will not be replaced.  

  
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For each endpoint, the analyses will be done using the corresponding evaluable population. 
 
8.3. 
Patients who discontinued sirolimus for reasons other than progression 
 
8.3.1. Main end-point 
 
Progression-free Survival (PFS-1) according to RECIST 1.1 from sirolimus discontinuation.  
PFS-1 time will be calculated from the date of sirolimus discontinuation to the date of 
progression according to RECIST 1.1 or death from any cause, whichever will occur first; time 
will be censored at the date of the last follow-up for the patients alive and without progression 
before the study cut-off. One sample log-rank test will be used to test the difference in 12-
month PFS-1 with the 20% hypothesized in the historical control 
 
8.3.2. Secondary end-points 
 
• ORR according to RECIST 1.1: point estimate will be calculated as the number of 
patients with CR and PR divided by the total number of patients who discontinued 
sirolimus; the exact 95% confidence interval will also be estimated. 
• Post-discontinuation OS (pdOS): time will be calculated from the date of sirolimus 
discontinuation to the date of death for any cause; time will be censored at the date of 
the last follow-up for the patients alive before the study cut-off. 
• Quality of life changes during sirolimus discontinuation interval according to EORTC 
QLQ-C30 questionnaire and ESAS. For both EORTC QLQ-C30 and ESAS 
questionnaires descriptive analyses will be performed: mean and standard deviation 
at each time will be estimated and, to represent trends over time, plots of mean scores 
will be depicted. 
 
 

  
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8.3.3. Exploratory end-points  
 
• PFS-1 according to RESCORe (Appendix 4) and pain progression (Appendix 3) 
following sirolimus discontinuation: time will be calculated from the date of sirolimus 
discontinuation to the date of progression according to RECIST 1.1 or death from any 
cause, whichever will occur first; time will be censored at the date of the last follow-up 
for the patients alive and without progression before the study cut-off. 
• Correlation between GDF-15 levels at predefined timepoints (baseline at the time of 
sirolimus discontinuation, at first disease radiological evaluation, disease progression) 
and PFS-1 according to RECIST 1.1 and pdOS: Descriptive analyses of GDF-15 time 
profile using appropriate plots (such as line plots and boxplots to show the distribution 
of values each time point for the different stratification groups) and descriptive statistics 
(such as mean, standard deviation , median, interquartile range (IQR), minimum, and 
maximum values at each time point) will be performed stratifying for PFS-1 status 
(progression or death present vs no events) and OS status (alive, death). These 
analyses have exploratory purposes, and no statistical testing will be performed. 
• Correlation between serosal effusion and PFS-1 according to RECIST 1.1 and pdOS. 
Kaplan-Meier PFS-1 and pdOS curves will be estimated in the 2 subgroups serosal 
effusion present or absent. These analyses have exploratory purposes, and no statistical 
testing will be performed. 
 
8.4. 
Patients who restart sirolimus for secondary progression 
 
8.4.1. Main end-point 
 
Progression-free Survival (PFS-2) according to RECIST 1.1, after sirolimus re-challenge: time 
will be calculated from the date of sirolimus restart to the date of progression or death from 

  
Protocol POEM_V6.0 22nd May 2025 
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any cause, whichever will occur first; time will be censored at the date of the last follow-up for 
the patients alive and progression-free before the study cut-off. 
 
8.4.2. Secondary endpoints  
 
• ORR according to RECIST 1.1: point estimate will be calculated as the number of 
patients with CR+PR divided by the total number of patients who restart sirolimus; the 
exact 95% confidence interval will also be estimated. 
• Duration of response according to RECIST 1.1 (DoR): DoR evaluation will be based 
on responders only and will be assessed regardless of treatment modifications of any 
kind. DoR time will be calculated from the date of the first documented response 
(complete or partial response) to the date of disease progression or death from any 
cause (in case of patients who die before evidence of disease progression); time will 
be censored at the date of the last follow-up for the patients alive before the study cut-
off. 
• Post-sirolimus rechallenge OS (psrOS): time will be calculated from the date of the 
first dose of sirolimus rechallenge to the date of death for any cause; time will be 
censored at the date of the last follow-up for the patients alive before the study cut-
off. 
• Quality of life changes during treatment according to EORTC QLQ-C30 questionnaire 
and ESAS: For both EORTC QLQ-C30 and ESAS questionnaires descriptive analyses 
will be performed: mean and standard deviation at each time will be estimated and, to 
represent trends over time, plots of mean scores will be depicted. 
  
 

  
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69 
 
8.4.2. Exploratory end-points  
 
• ORR by RESCORe criteria (Appendix 4) and pain assessment criteria (Appendix 3): 
a point estimate will be calculated as the number of patients with CR+PR divided by 
the total number of patients who restart sirolimus; the exact 95% confidence interval 
will also be estimated. 
• PFS-2 by RESCORe (Appendix 4) and pain changes (Appendix 3): time will be 
calculated from the date of sirolimus restart to the date of progression or death from 
any cause, whichever will occur first; time will be censored at the date of the last follow-
up for the patients alive and progression-free before the study cut-off. 
• The PFS-1, pdOS, DoR, PFS-2, and psrOS curves will be estimated with the Kaplan-
Meier method. Summaries of Kaplan-Meier and crude cumulative incidence curves 
will be estimated at specific timepoints of clinical interest, together with the 95% 
confidence intervals, along with median times and corresponding interquartile ranges. 

  
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REFERENCES 
 
Giani, C., Dimino, A., Miceli, R., 2024. Patients with advanced epithelioid hemangioendothelioma 
treated with sirolimus: outcome following sirolimus discontinuation. Presented at the Connective 
Tissue Oncology Society Annual Conference. 
Giani, C., Miceli, R., Baldi, G.G., Brunello, A., Vincenzi, B., Morosi, C., Greco, F.G., Gronchi, A., 
Ingrosso, M., Frezza, A.M., Casali, P.G., Ljevar, S., Stacchiotti, S., 2023. Outcome of patients (PTS) 
with advanced epithelioid hemangioendothelioma (EHE) after failure on sirolimus (S). J. Clin. Oncol. 
https://doi.org/10.1200/JCO.2023.41.16_suppl.11574 
Gronchi, A., Miah, A.B., Dei Tos, A.P., Abecassis, N., Bajpai, J., Bauer, S., Biagini, R., Bielack, S., 
Blay, J.Y., Bolle, S., Bonvalot, S., Boukovinas, I., Bovee, J.V.M.G., Boye, K., Brennan, B., 
Brodowicz, T., Buonadonna, A., De Álava, E., Del Muro, X.G., Dufresne, A., Eriksson, M., Fagioli, 
F., Fedenko, A., Ferraresi, V., Ferrari, A., Frezza, A.M., Gasperoni, S., Gelderblom, H., Gouin, F., 
Grignani, G., Haas, R., Hassan, A.B., Hecker-Nolting, S., Hindi, N., Hohenberger, P., Joensuu, H., 
Jones, R.L., Jungels, C., Jutte, P., Kager, L., Kasper, B., Kawai, A., Kopeckova, K., Krákorová, D.A., 
Le Cesne, A., Le Grange, F., Legius, E., Leithner, A., Lopez-Pousa, A., Martin-Broto, J., Merimsky, 
O., Messiou, C., Mir, O., Montemurro, M., Morland, B., Morosi, C., Palmerini, E., Pantaleo, M.A., 
Piana, R., Piperno-Neumann, S., Reichardt, P., Rutkowski, P., Safwat, A.A., Sangalli, C., Sbaraglia, 
M., Scheipl, S., Schöffski, P., Sleijfer, S., Strauss, D., Strauss, S., Sundby Hall, K., Trama, A., Unk, 
M., van de Sande, M.A.J., van der Graaf, W.T.A., van Houdt, W.J., Frebourg, T., Casali, P.G., 
Stacchiotti, 
S., 
ESMO 
Guidelines 
Committee, 
E. 
and 
GENTURIS.E. 
address: 
clinicalguidelines@esmo.org, 2021. Soft tissue and visceral sarcomas: ESMO-EURACAN-
GENTURIS Clinical Practice Guidelines for diagnosis, treatment and follow-up☆. Ann. Oncol. Off. 
J. Eur. Soc. Med. Oncol. 32, 1348–1365. https://doi.org/10.1016/j.annonc.2021.07.006 
Stacchiotti, S., Miah, A.B., Frezza, A.M., Messiou, C., Morosi, C., Caraceni, A., Antonescu, C.R., 
Bajpai, J., Baldini, E., Bauer, S., Biagini, R., Bielack, S., Blay, J.Y., Bonvalot, S., Boukovinas, I., 
Bovee, J.V.M.G., Boye, K., Brodowicz, T., Callegaro, D., De Alava, E., Deoras-Sutliff, M., Dufresne, 
A., Eriksson, M., Errani, C., Fedenko, A., Ferraresi, V., Ferrari, A., Fletcher, C.D.M., Garcia Del 
Muro, X., Gelderblom, H., Gladdy, R.A., Gouin, F., Grignani, G., Gutkovich, J., Haas, R., Hindi, N., 
Hohenberger, P., Huang, P., Joensuu, H., Jones, R.L., Jungels, C., Kasper, B., Kawai, A., Le Cesne, 
A., Le Grange, F., Leithner, A., Leonard, H., Lopez Pousa, A., Martin Broto, J., Merimsky, O., 
Merriam, P., Miceli, R., Mir, O., Molinari, M., Montemurro, M., Oldani, G., Palmerini, E., Pantaleo, 
M.A., Patel, S., Piperno-Neumann, S., Raut, C.P., Ravi, V., Razak, A.R.A., Reichardt, P., Rubin, 
B.P., Rutkowski, P., Safwat, A.A., Sangalli, C., Sapisochin, G., Sbaraglia, M., Scheipl, S., Schöffski, 
P., Strauss, D., Strauss, S.J., Sundby Hall, K., Tap, W.D., Trama, A., Tweddle, A., van der Graaf, 

  
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W.T.A., Van De Sande, M. a. J., Van Houdt, W., van Oortmerssen, G., Wagner, A.J., Wartenberg, 
M., Wood, J., Zaffaroni, N., Zimmermann, C., Casali, P.G., Dei Tos, A.P., Gronchi, A., 2021. 
Epithelioid hemangioendothelioma, an ultra-rare cancer: a consensus paper from the community of 
experts. ESMO Open 6, 100170. https://doi.org/10.1016/j.esmoop.2021.100170 
Stacchiotti, Silvia, Simeone, N., Lo Vullo, S., Baldi, G.G., Brunello, A., Vincenzi, B., Palassini, E., 
Dagrada, G.P., Collini, P., Morosi, C., Greco, F.G., Sbaraglia, M., Dei Tos, A.P., Mariani, L., Frezza, 
A.M., Casali, P.G., 2021. Activity of sirolimus in patients with progressive epithelioid 
hemangioendothelioma: A case-series analysis within the Italian Rare Cancer Network. Cancer 127, 
569–576. https://doi.org/10.1002/cncr.33247 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

  
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APPENDIX 3 
 
PAIN ASSESSMENT CRITERIA (PAC) 
 
BACKGROUND 
 
In cancer patients with neoplastic pleural or peritoneal involvement, pain can be classified by 
assessing etiology and clinical characteristics and by pain syndrome recognition following 
established criteria, such as the IASP Task Force (ITF) (Caraceni et al., 1999; Portenoy and 
Ahmed, 2018), ICD-11 (Perrot et al., 2019) and expert recommendations (Caraceni, 2001). For 
an accurate definition of these characteristics, specialist evaluation (Palliative Care or Pain 
Specialist) is recommended, in particular for those patients with severe pain. Through clinical 
criteria, we can describe typical pain patterns in patients with epithelioid hemangioendothelioma 
(EHE) and, particularly but not exclusively, pain related to the presence of serosal / pleural 
involvement. 
 
In patients affected by EHE with pleural involvement, the typical syndrome manifests as 
nociceptive somatic pain in the ipsilateral hemithorax, described as constrictive, persistent, and 
associated with exacerbations. These exacerbations can occur either due to pleural stretching 
(deep breaths) or in the absence of clear triggers; moreover, this excruciating pain may reduce 
the mobility of the hemithorax and of the homolateral shoulder. Sometimes, it is also possible to 
observe a neuropathic component, described as a well localized superficial pain, often radiating 
to the anterior chest wall due to involvement of the intercostal nerves (from T1 to T11). This pain 
may be evoked by pressuring the Valleix points due to irritation of compressed nerve fibers. 
Depending on local spread of the disease (i.e, to paravertebral structures) patients can also 
report poorly localized back pain, exacerbated when lying down, and disturbing sleep. Pain 
characteristics may vary depending on the sites of disease progression; for example, patients 
may develop visceral pain, described as deep retrosternal and poorly localized pain, if heart, 

  
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pericardium, large vessels and/or esophagus are involved.   
 
In EHE patients with peritoneal involvement, nociceptive somatic or visceral pain can be 
observed in different abdominal quadrants, described as constrictive, persistent, and associated 
with exacerbations. Exacerbations may have characteristics of colic pain, even leading to sub-
occlusive or occlusive intestinal conditions. In the case of peritoneal disease, the neuropathic 
component is typically absent but may manifest in the case of retroperitoneal nodal involvement.  
 
Pain in EHE can also be due to the spread of the disease to different distant tissues, such as 
liver, bone or nervous tissues. 
 
Usually, pain related to serosal infiltration rapidly worsens and it is the worst pain intensity that 
is the main factor affecting the quality of life of these patients, while average pain intensity can 
be moderate and constant. This condition is often described as breakthrough pain (Caraceni et 
al., 2004). It is not uncommon to find poor response to opioids, while frequently there is a good 
response to NSAIDs (e.g., ketorolac). 
 
When pain is severe independently from its cause a specialist evaluation is still recommended 
to accurately define the pain etiology and characteristics. The Palliative Care Specialist or Pain 
Therapist should also set the appropriate therapy for the pain features. 
 
Pain assessment criteria 
 
To assess disease status by means of clinical criteria and to accurately determine pain 
syndromes and assess pain progression, patients’ pain evaluations should be conducted by a 
Palliative Care or Pain Specialist. At each follow-up visit, the patient will complete a modified 
Brief Pain Inventory (BPI) (Serlin et al., 1995), with pain assessment referring to the last week 

  
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instead of the last 24 hours. The 7-day interval was chosen as it provides more information than 
the 24-hour interval. Additionally, we selected Worst Pain Intensity (WPI) as the reference 
parameter rather than Average Pain Intensity (API) since it is the former that has a more 
significant impact on these patients' quality of life and overall pain. This is consistent with 
previous studies reporting the WPI as possibly more impactful than API on pain evaluation 
(Atkinson et al., 2010; Harris et al., 2007). 
 
The relationship between pain and tumor will be defined based on the site of pain and the 
components of the pain syndrome. Tumor-related pain will be then assessed according to the 
following criteria. In the event of multiple painful lesions, the site associated with the highest level 
of WPI will be used as the response parameter, but all other pains will be recorded. 
 
The WPI must be > 4 in order to be used as a parameter of response, as this pain intensity 
provides a threshold for clinically significant WPI. 
 
Baseline pain evaluation for pain response should be done from 3 to 7 seven days after starting 
an adequate analgesic treatment and before starting anti-neoplastic treatment; response 
evaluation will be done at least 6 weeks after the administration of specific therapy. Within this 
time frame, it should be possible to estimate the drug activity. Pain assessment and response 
should be implemented also in patients who are without pain at baseline, and who develop pain 
while on treatment using the same criteria. 
 
 
Pain intensity assessment 
 
The status of the disease will be primarily evaluated by pain intensity assessment. According to 
literature, the 30% change cut-off was chosen to identify a clinically relevant pain change (Corli 

  
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et al., 2013; Dworkin et al., 2008; Farrar et al., 2001). Previous studies have also found other 
cut-offs, such as a 2-point reduction on a scale from 0 to 10, as clinically significant when 
evaluating pain response. However, we have opted for a percentage threshold as we believe it 
to be the most reliable across all pain ranges (Corli et al., 2013). 
 
Analgesic drug assessment 
 
Pain response criteria cannot disregard analgesic drug assessment. While an appropriate pain 
therapy will be started before the baseline evaluation, it is very likely that dosage adjustment 
and/or drug change will be needed throughout the following weeks. Therefore, keeping in 
consideration the analgesic therapy modification will be essential to assess tumor response 
throughout pain. 
If a switch in opioid is performed, the equianalgesic dose between the current and previous drug 
will be used to evaluate the disease status. As it is not possible to assess an equianalgesic dose 
of NSAIDs, for this family, the total dose will be taken as reference, although these patients often 
require the use of NSAIDs with high anti-inflammatory potency (e.g., ketorolac) (Buckley and 
Brogden, 1990; Patrignani and Patrono, 2015). Since different NSAIDs have various therapeutic 
dosages, if a switch in NSAIDs is performed, it will not be possible to assess the disease status 
using the NSAIDs daily dose. The assessment will be resumed at the next visit. 
 
When assessing the analgesic daily dose, it is necessary to take into consideration the total 
rescue pain drug dose added to the background therapy dose. To determine the daily dose of 
rescue pain medication, the total amount administered over the previous 7 days is calculated 
and subsequently divided by 7, providing the average daily dose required for rescue analgesia. 
 
For the criteria regarding opioid/NSAID dose increase or reduction, the doses of the two drug 
families will be evaluated separately. A significant increase or reduction (see criteria) in one of 

  
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the two drug families will be sufficient to define PD or PR respectively. Although unlikely, it is 
possible that the trend of doses of the two drug families is not consistent (e.g., opioid reduction 
and NSAID increase). In this case, the change with the greater magnitude will be relevant for 
evaluation if the opposite change is no more than 10%. If the two dose changes are inconsistent 
and exceed 10% of the respective dose, in the absence of significant changes in WPI (see 
criteria), SD status will be maintained. 
 
Pain Assessment Criteria  
 
The criteria are the following: 
• COMPLETE RESPONSE (CR), WPI=0 with no more than a 10% increase in 
opioid/NSAID daily dose; 
• PARTIAL RESPONSE (PR), at least a 30% decrease in WPI with no more than a 10% 
increase in opioid/NSAID daily dose, and/or at least a 30% reduction in opioid/NSAID 
daily dose with no more than a 1-point increase in WPI; 
• STABLE DISEASE (SD), WPI and/or opioid/NSAID daily dose variations that do not meet 
PR or PD criteria; 
• PROGRESSIVE DISEASE (PD), at least a 30% increase in WPI with no more than a 10% 
reduction in opioid/NSAID daily dose, and/or at least a 30% increase in opioid/NSAID 
daily dose with no more than a 1-point reduction in WPI and/or the development of new 
disease related pain with a WPI more than 4. 
In the event that the patient experiences pain progression at a different metastatic site from the 
one initially selected as the target to monitor pain changes, the reference pain can be changed, 
taking into consideration the anatomic location affected by the pain associated with the highest 
WPI. This evaluation must be performed by a Palliative Care or Pain Specialist. 
 
To ensure accurate pain evaluation, patients will be instructed to document WPI, baseline 

  
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analgesic regimen, and usage of rescue pain medication in a structured paper diary every 
evening. Palliative Care/Pain specialist follow up will be performed at least once a month for the 
first six months to monitor pain progression and optimize pain management. These FU may be 
conducted via telemedicine, if clinically appropriate. After six months, the FU visit should be 
performed within one week from the oncological FU visit. Pain assessment-based evaluations of 
disease status will be performed during the visit nearest to each scheduled radiological 
assessment (refer to Appendix 2) 
 
 
Exclusion or Drop-out criteria 
 
Since these criteria are based on the clinical evaluation of the patient, there may be 
circumstances in which tumor-related pain assessment is to be considered not evaluable. In 
detail, the unavailability of the assessment can be defined in presence of one (or more) of the 
following: 
• inability of the patient to define the intensity of his/her own pain (e.g., in cases of cognitive 
impairment); 
• increase of pain due to factors unrelated to tumor progression (e.g., tumor region 
infection); 
• significant lack of compliance with analgesic therapy; 
• every situation unrelated to the tumor that may affect or jeopardize the correct pain 
evaluation according to the clinician; 
• evaluation conducted by someone other than a Palliative Care Specialist or a Pain 
Therapist. 
 
 
 

  
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Examples: 
 
• CR: Baseline WPI of 8/10 with oral daily morphine 100 mg → WPI at the visit 0/10 with 
oral daily morphine 100/110 mg 
 
• PR: Baseline WPI of 8/10 with oral daily morphine 100 mg → WPI at the visit 5/10 with 
oral daily morphine 100/110 mg  
Or 
• PR: Baseline WPI of 5/10 with oral daily morphine 100 mg → WPI at the visit 6/10 with 
oral daily morphine 60 mg  
Or 
• PR: Baseline WPI of 5/10 with oral daily morphine 100 mg and oral daily ketorolac 60 mg 
→ WPI at the visit 6/10 with oral daily morphine 60 mg and oral daily ketorolac 65 mg 
 
• SD: Baseline WPI of 8/10 with oral daily morphine 100 mg → WPI at the visit 6/10 with 
oral daily morphine 100/110 mg (trend towards PR, but still not meeting the criteria) 
Or 
• SD: Baseline WPI of 5/10 with oral daily morphine 100 mg → WPI at the visit 6/10 with 
oral daily morphine 80 mg (trend towards PR, but still not meeting the criteria) 
Or 
• SD: Baseline WPI of 5/10 with oral daily morphine 100 mg → WPI at the visit 10/10 with 
oral daily morphine 0 mg (pain exacerbation due to inappropriate reduction of analgesic 
therapy)  
Or 
• SD: Baseline WPI of 8/10 with oral daily morphine 100 mg → WPI at the visit 2/10 with 
oral daily morphine 150 mg (pain reduction due to response to increased analgesic 
therapy)  

  
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Or 
• SD: Baseline WPI of 7/10 with oral daily morphine 100 mg and oral daily ketorolac 60 mg 
→ WPI at the visit 6/10 with oral daily morphine 50 mg and oral daily ketorolac 90 mg 
(inconsistent variations in opioid and NSAID doses exceeding the 10% of the starting 
dose, with pain without significant variations)  
Or 
• SD: Baseline WPI of 8/10 with oral daily morphine 100 mg → WPI at the visit 9/10 with 
oral daily morphine 100/110 mg (trend towards PD, but still not meeting the criteria) 
Or 
• SD: Baseline WPI of 5/10 with oral daily morphine 100 mg → WPI at the visit 6/10 with 
oral daily morphine 120 mg (trend towards PD, but still not meeting the criteria) 
 
• PD: Baseline WPI of 8/10 with oral daily morphine 100 mg → WPI at the visit 8/10 with 
oral daily morphine 130 mg  
Or 
• PD: Baseline WPI of 8/10 with oral daily morphine 100 mg and oral daily ketorolac 90 mg 
→ WPI at the visit 8/10 with oral daily morphine 130 mg and oral daily ketorolac 85 mg  
Or 
• PD: Baseline WPI of 5/10 with oral daily morphine 100 mg → WPI at the visit 8/10 with 
oral daily morphine 100 mg 
Or 
• PD: Baseline upper right arm WPI of 5/10 with oral daily morphine 100 mg → upper right 
arm WPI at the visit 6/10 with oral daily morphine 110 mg plus the development of a 
constrictive, persistent, pain in the right hemithorax, associated with exacerbations with 
a WPI 6/10 
 

  
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Cella, D., Chandler, J., Cowan, P., Dimitrova, R., Dionne, R., Hertz, S., Jadad, A.R., Katz, 

  
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N.P., Kehlet, H., Kramer, L.D., Manning, D.C., McCormick, C., McDermott, M.P., McQuay, 
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APPENDIX 4 
 
Response Evaluation by Serosal Changes and Outcomes Reporting 
(RESCORe) criteria 
 
 
1. RATIONALE AND BACKGROUND  
 
Aggressive forms of EHE are often associated with systemic symptoms (tumor-related pain, 
fever, fatigue, shortness of breath and weight loss) and serosal involvement, either in the form 
of effusion, thickening of serosal layers (either focal or diffuse) or both.  
In such cases, disease progression appears to be temporally correlated with the onset or 
worsening of serosal involvement, which can occur without evidence of new lesions or threshold 
growth of existing ones and cannot therefore be detected by Response Evaluation Criteria In 
Solid Tumors (RECIST) 1.1 (Frezza et al., 2021; Lau et al., 2011; Rosenbaum et al., 2020).  
Refinement of radiologic response criteria is an emerging field of investigation in the sarcoma 
community. 
RECIST 1.1 have recently been proven suboptimal predictors of clinical outcomes in patients 
affected by high-risk soft-tissue sarcomas of the extremities and superficial trunk (Vanzulli et al, 
2025). 
Disease-specific radiologic response criteria have also been proposed for malignant 
mesothelioma, based on the assumption that this tumor displays a peculiar pattern of growth 
which is not adequately captured by RECIST (Byrne et al, 2004; Armato et al, 2018). 
This study aligns with such trajectory of research by proposing an alternative exploratory 
response assessment score, the Response Evaluation by Serosal Changes and Outcomes 
Reporting (RESCORe) criteria (see also Table 1). 

  
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2. DEFINITION 
 
• RESCORe Complete Response (CR) was assigned if CR for RECIST 1.1 and no 
serosal involvement (defined as either focal/diffuse thickening of serosal layers, effusion 
or both) was observed or had completely resolved if present at prior studies; 
• RESCORe Partial Response (PR) was assigned in two distinct scenarios:  
a. PR according to RECIST 1.1 and no new effusion or existing effusion did not 
increase g 40%* and no new nor unequivocal increase of existing serosal layers 
involvement; 
b. Reduction in the sum of the longest diameters of target lesions 10% < x < 30% 
and serosal effusion reduced g 66%* and no new nor unequivocal increase of 
existing serosal layers involvement; 
• RESCORe Progressive Disease (PD) was assigned if PD per RECIST 1.1 or new 
effusion or existing effusion increased g 40%* (or up to complete occupation of 
pleural/peritoneal cavity) or new/unequivocal increase of serosal layers involvement; 
• RESCORe Stable Disease (SD) was assigned in cases not qualifying for either CR, PR 
or PD. 
*** volumetric assessment 
The thresholds above were partially derived from previous work by Orsatti et al, who compared 
the performances of uni-, bi- and tri-dimensional response criteria in the setting of 
rhabdomyosarcoma. 
 
3. EVALUABLE PATIENTS 
 
RESCORe criteria are not applicable in case of: 
1. Active interventions to treat and/or prevent serosal involvement, such as 
thoracentesis/paracentesis or chest/abdominal drainages; 

  
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2. Clinical evidence supporting non-neoplastic origin of effusion, for example confirmed 
bacterial/viral pneumonia, thoracic traumas, cardiac failure, or suspected drug-induced 
effusion. 
A standardized, EHE-tailored checklist is proposed to ensure all relevant findings are 
investigated by the reporting radiologist: 
1. Pleural effusion observed: Y/N;  
1.1 If Y to 1: Pleural effusion already observed at latest prior: Y/N; 
1.2 If Y to 2: Please specify % variation of pleural effusion (volumetric assessment; 
including comparison with all available priors); if stable, specify duration of stability; 
1.3 If N to 2: Please alert principal provider of care; 
2. Pleural thickening (either focal or diffuse) observed: Y/N; 
2.1 If Y to 5: Pleural thickening already observed at latest prior: Y/N; 
2.2 If Y to 6: Please describe any changes in pleural involvement (including comparison 
with all available priors); 
2.3 If N to 6: Please alert principal provider of care  
3. Peritoneal involvement observed: Y/N; 
3.1 If Y to 9: Peritoneal effusion already observed at latest prior: Y/N; 
3.2 If Y to 10: describe any changes in peritoneal effusion (including comparison with all 
available priors); 
3.3 If N to 10: Please alert principal provider of care  
Legend: Y = yes; N = no 
 
 

  
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Table 1. RESCORe criteria. 
CR: complete response; PR: partial response; SD: stable disease; PD: progressive disease; LN: 
lymph node; SLD: sum of longest diameters. 
 
RESCORe 
category 
Target lesions 
Non-target 
lesions 
New 
lesions 
Serosal 
involvement 
CR 
-Disappearance of all 
lesions 
  -LN axis < 10 mm 
 
Disappearance 
of all lesions 
 
No 
No or completely 
resolved 
PR 
Decrease g 30% of 
SLDs from baseline 
(g 4 weeks) 
No progression 
No 
No new 
involvement, 
effusion increase 
< 40%, no 
unequivocal 
increase in 
serosal layers 
involvement 
PR 
Decrease 10% < x < 
30% of SLDs from 
baseline  
(g 4 weeks) 
No progression 
No 
No new 
involvement, 
effusion reduced 
g 66%, no 
unequivocal 
increase in 
serosal layers 
involvement 
PD 
g 20% increase of LSD 
from nadir with an 
absolute increase g 5 
mm 
 
Unequivocal 
progression in 
lesion size 
 
Yes 
 
 
New 
involvement or 
effusion increase 
g 40% or 
unequivocal 
increase in 
serosal layers 
involvement 
SD 
Does not qualify for CR, 
PR nor PD, nadir as 
reference  
Persistence of 
one or more  
No 
No new 
involvement, 
effusion changes 
within 
thresholds, no 
unequivocal 
increase in 
serosal layers 
involvement 

  
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FIGURES 
 
 
 
 
 
Figure 1. Development of bilateral pleural effusion in a patient with aggressive EHE 
 
Figure 2. Development of peritoneal effusion in a patient with aggressive EHE 
 

  
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Figure 3. Early signs of pleural involvement may be represented by subtle thickening of pleural 
layers 

  
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Figure 4. Quantification of pleural effusion can be performed with the aid of dedicated tools for 
image segmentation, such as 3DSlicer. 
 
 
 
  

  
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Figure 5. Pleuro-parenchymal lung involvement may also be inferred from computing residual 
ventilated lung with the aid of semi-automated segmentation tools 
 
 
 
 
 
 
Figure 6. Quantification of peritoneal effusion can be performed with the aid of dedicated tools 
for fully automated image segmentation (Hou et al, 2024). 
 
 
 
 
 

  
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