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Particle-based Partial Tumor Irradiation of Unresectable Bulky Tumors

Particle-based Partial Tumor Irradiation Targeting Hypoxic Segment and Sparing the Peritumoral Immune Microenvironment for Unresectable Bulky Tumors

Status
Terminated
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04875871
Acronym
PARTICLE-PATHY
Enrollment
13
Registered
2021-05-06
Start date
2021-11-11
Completion date
2025-03-14
Last updated
2025-05-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Cancer

Keywords

Particle Radiotherapy, Partial Tumor Irradiation

Brief summary

This study uses a novel, recently developed unconventional radiotherapy technique which consists of three high-dose fractions directed to special segments of unresectable bulky tumors.

Detailed description

This is a mono-centric, prospective, two-arms, feasibility study in which the investigator will enroll up to 22 patients with locally advanced or metastatic cancers with at least one bulky (≥6cm) lesion. This study uses a novel, recently developed unconventional radiotherapy technique, consisting of a short course (3 fractions) high dose partial irradiation targeting exclusively the hypoxic segment of unresectable bulky tumors while sparing the peritumoral immune microenvironment for induction of immune-mediated tumoricidal bystander and abscopal effects. The present study will explore the potential biological and physical advantages of particle-based radiotherapy to deliver a highly conformal radiation dose to the hypoxic tumor segment defined by using hypoxia-specific Copper-64-Diacetyl-bis (N4-methylthiosemicarbazone) Positron Emission Tomography-Computer Tomography (64Cu-ATSM PET-CT) and dynamic contrast enhanced Magnetic Resonance Tomography imaging. Based on tumor location, volume and risk factors related to nearby organs at risk, patients will be divided in the high-dose or reduced-dose group which will be treated with different dose-schedules according to risk factors. Additionally, radiotherapy will be administered at the precise timing, determined individually for each patient, based on the serially mapped homeostatic immune fluctuations by monitoring blood levels of the inflammatory markers. The objective is to synchronize the radiation treatment with the favorable, most reactive anti-tumor immune response phase, in order to break tumor´s immune-tolerance locally and systemically.

Interventions

RADIATIONParticle radiotherapy

Partial radiotherapy targeting the hypoxic tumor segment

DIAGNOSTIC_TESTMagnetic resonance imaging

For treatment planning as well as for follow-up radiological tumor assessment.

DIAGNOSTIC_TESTComputertomography

For treatment planning as well as for follow-up radiological tumor assessment.

DIAGNOSTIC_TESTCopper-64-Diacetyl-bis (N4-methylthiosemicarbazone) Positron Emission Tomography-Computer Tomography (64Cu-ATSM-PET-CT)

For the definition of the hypoxic tumor segment in treatment planning.

DIAGNOSTIC_TESTBlood sampling

Evaluation before treatment-start, during treatment and follow-up period.

Sponsors

Medical University of Vienna
CollaboratorOTHER
Landesklinkum Wiener Neustadt
CollaboratorOTHER
Klinik Ottakring
CollaboratorUNKNOWN
EBG MedAustron GmbH
Lead SponsorINDUSTRY

Study design

Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

1. Written informed consent obtained from the patient prior to performing any treatment-related procedures. 2. Biopsy proven malignant unresectable solid bulky primary or recurrent tumor (diameter of at least 6 cm or greater, except for the Central Nervous System (CNS) tumors), or in a case of lack of recent biopsy progression on at least two consecutive radiological examinations, with biopsy proof in the past. Presence of locally advanced (cN+) and/or metastatic disease will be accepted in order to allow for assessment of the abscopal effects. 3. Ineligibility for standard treatments including surgery, conventional (whole tumor) radiotherapy and systemic therapy, or being in progression or stable (with no response to systemic treatment) under systemic therapy. 4. A minimum time interval from last dose of systemic therapy before radiotherapy of two weeks; Systemic therapy may be resumed 4 weeks following radiotherapy in order to permit assessment of the treatment efficacy. 5. Median life expectancy of \>2 months. 6. Age \> 18 years. 7. Adequate bone marrow function as follows below: Haemoglobin ≥ 8.0 g/d; Absolute neutrophil count (ANC) ≥ 1.5 x 10ꝰ/L (\> 1500 per mm3); Platelet count ≥ 100 x 10ꝰ/L (\>100,000 per mm3). 8. Female patients must either be of non-reproductive potential (i.e. post-menopausal by history: ≥60 years old and no menses for ≥1 year without an alternative medical cause; OR history of hysterectomy, OR history of bilateral tubal ligation, OR history of bilateral oophorectomy) OR women of fertile age must have adequate conception prevention measures and must have a negative serum pregnancy test upon study entry. 9. Patient is willing and able to comply with the follow up including scheduled visits and examinations.

Exclusion criteria

1. Patients without bulky lesions. 2. Tumors suitable for the standard therapies including surgery, conventional (whole tumor) irradiation and systemic therapies. 3. Median life expectancy of less than 2 months. 4. Contraindication to i.v. Computer Tomography and Magnetic Resonance Tomography contrast medium administration, particularly estimated glomerular filtration rate (GFR) less than 45 mL/min/1.73 m2. 5. History of autoimmune disease. 6. Current or prior use of immunosuppressive medication within 14 days before enrollment with the exceptions of intranasal and inhaled corticosteroids or systemic corticosteroids at physiological doses, which are not to exceed 10 mg/day of prednisone, or an equivalent corticosteroid. 7. History of primary immunodeficiency. 8. History of allogeneic organ transplant. 9. Uncontrolled intercurrent comorbidity including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, uncontrolled hypertension, unstable angina pectoris, active bleeding diatheses including any patient known to have evidence of acute or chronic hepatitis B, hepatitis C or human immunodeficiency virus (HIV), or psychiatric illness/social situations that would limit compliance with study requirements or compromise the ability of the patient to give written informed consent. 10. Female patients who are pregnant, breast-feeding or male or female patients of reproductive potential who are not employing an effective method of birth control. 11. Any condition that, in the opinion of the investigator, would interfere with evaluation of study treatment or interpretation of patient safety or study results. (Note: criterion will be evaluated on the four eyes principle, evaluated by both Principle Investigator and Sub-Investigators.) 12. Patients with uncontrolled seizures.

Design outcomes

Primary

MeasureTime frameDescription
Bystander (local) tumor response rate11 months (after treatment)Bystander (local, at the level of the partially treated bulky tumor) response rate defined as at least a 30% regression of the unirradiated tumor tissue.

Secondary

MeasureTime frameDescription
Overall survival11 months (after treatment)Defined as the time from treatment until the time of death from any cause.
Time to local tumor progression11 months (after treatment)Defined as the time from treatment until the time of local disease progression.
Time to distant tumor progression11 months (after treatment)Defined as the time from treatment until the time of distant disease progression.
Abscopal (distant) tumor response rate11 months (after treatment)Defined as the proportion of metastatic patients that exhibited an abscopal effect versus the total number of metastatic patients allocated to the treatment.
Feasibility of PARTICLE-PATHY3,5 years (recruiting time + treatment time + 11 months follow-up)Feasibility of patient recruitment, treatment and follow-up rates.
Radiation related toxicity11 months (after treatment)Toxicity assessment according to NCI CTCAE v5.0
Feasibility of timing of PARTICLE-PATHY and its relation to clinical outcomesUntil 11 months after treatmentThe feasibility of PARTICLE-PATHY and to it related TIMING will be defined by the proportion of patients allocated to this treatment who received it within dosimetric constraints after being able to define the immune-cycle periodicity and to synchronize radiotherapy with it versus the total number of patients allocated to the treatment.
Bystander/abscopal response rate in relation to dose-size of Peritumoral Immune Microenvironment (PIM)11 months (after treatment)See title
Bystander/abscopal response rate in relation to Interleukin-2 and Interferon Gamma values11 months (after treatment)Two key cytokines, Interleukin-2 (IL-2) and Interferon Gamma (INFg), will be serially assessed at baseline and after each radiotherapy treatment, in order to determine their potential role in modulating the immune response in relation to the bystander/abscopal effects.
Symptoms relief11 months (after treatment)Proportion of patients who will achieve a partial or complete relief at different time-points.

Countries

Austria

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026