Ventricular TachycardiaPhase 1DEFT STARNCT05594368
Dose Escalation for SBRT of Recurrent VT Ventricular Tachyarrhythmia - a Single Center, Phase II Clinical Trial
A Phase 1 study testing Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT) in people with Ventricular Tachycardia, run by University of Zurich at 3 sites in 2 countries.
Trial summary
The objective of this study is to demonstrate that higher radiation doses are necessary to induce transmural scar formation which is currently assumed to be the underlying mechanism of successful long-term efficacy of VT treatment and therefore dose-escalation will lead to a significantly reduced long-term VT… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Ventricular Tachycardia
- What is being tested?
- Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT)
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 15 participants
- Where
- 3 sitesin 2 countries
- Study dates
- 1 Jul 2022to 31 Dec 2028
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients with structural heart disease, in particular ischemic and non-ischemic cardiomyopathy: Implanted ICD and/or CRT-D. Prior ≥1 failed catheter ablation (with endocardial ± epicardial approach based on the substrate location and the ECG morphology of clinical VTs) procedure to control sustained monomorphic VT using currently recommended mapping and ablation techniques,2 or patients in whom ablation is not feasible. Reasons for lack of epicardial ablation and non-feasibility of catheter ablation must be specified. Sustained VT recurrence after catheter ablation on optimised antiarrhythmic medication.
- Age ≥18 years. IRB-approved, written informed consent must be provided
Who cannot join
- Patients with only premature ventricular contractions.
- Patients with sustained VT/VF who demonstrate:
- Acute myocardial infarction; Primary electrical disease (channelopathy); Reversible and treatable cause (e.g., drug-induced or intoxication) of VT that can be adequately addressed otherwise; A target that cannot be safely and precisely defined based on stereotactic radiotherapy accuracy requirements (e.g., anatomical interference from OARs, overlapping prior radiation therapy to the thoracic region); Pregnancy or breastfeeding; Inability to provide informed consent.
Trial locations and contacts
3 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
3 sites in 2 countries
Switzerland2 sites, 2 recruiting
- Recruiting
Inselspital Bern
Bern
Boldizsár Kovács, Dr. med., +41 31 632 50 00, boldizsar.kovacs@insel.ch
- Recruiting
University Hospital Zurich
Zurich, Canton of Zurich, 8091
Michael Mayinger, MD, 0041432530691, michael.mayinger@usz.ch
Czechia1 site, 1 recruiting
- Recruiting
University Hospital Ostrava
Ostrava
Jakub Cvek, Prof., +420 597 372 142, jakub.cvek@fno.cz
About this study
Official title: Dose Escalation for Stereotactic Cardiac Radiation Therapy of Recurrent Ventricular Tachyarrhythmia - a Multi Center, Phase II Clinical Trial
The objective of this study is to demonstrate that higher radiation doses are necessary to induce transmural scar formation which is currently assumed to be the underlying mechanism of successful long-term efficacy of VT treatment and therefore dose-escalation will lead to a significantly reduced long-term VT recurrence rate compared to the currently applied single dose of 25 Gy.
- Conditions
- Ventricular Tachycardia
- Being tested
- Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT)
- Medical subject headings
- Tachycardia, Ventricular
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT)Device
Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT) refractory to conventional antiarrhythmic and catheter ablation-based therapy. First patients will be treated with a dose from 25 Gy prescribed to the 65-90% target volume encompassing isodose escalating to a maximum of 32.5 Gy prescribed to the 65-90% isodose.
| Study group | Role | What they receive |
|---|---|---|
| Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT) | Experimental | Not described Receives: Device: Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT) |
What is being measured
The primary outcome is the main question the study is designed to answer.
safety measured by registered radiation associated adverse events up to 90 days
safety measured by registered radiation associated adverse events
Measured: up to 90 days
Secondary outcomes (1)
Radiation associated serious adverse event (at least grade 4 or 5 according to CTCAE v5)
Measured: As assessed at 90 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Oct 2022
- Study start1 Jul 2022
- Primary completion31 Dec 2027 (estimated)
- Study completion31 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Ventricular TachycardiaStudies of the same condition, open and under way.
- More trials run by University of ZurichThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- The study is designed as a one arm, multi-center dose escalation trial employing the i3+3 design.
- Masking
- None (open label)
- Enrolment
- 15 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Zurich
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05594368
- Sponsor's protocol ID
- 2022-00262
- Acronym
- DEFT STAR
- Status last verified
- Aug 2026
- First submitted
- 21 Oct 2022
- Last updated
- 21 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Kovacs B, Mayinger M, Ehrbar S, Fesslmeier D, Ahmadsei M, Sazgary L, Manka R, Alkadhi H, Ruschitzka F, Duru F, Papachristofilou A, Sticherling C, Blamek S, Golba KS, Guckenberger M, Saguner AM, Andratschke N. Dose escalation for stereotactic arrhythmia radioablation of recurrent ventricular tachyarrhythmia - a phase II clinical trial. Radiat Oncol. 2023 Nov 8;18(1):185. doi: 10.1186/s13014-023-02361-x.
PubMed 37941012
Study at a glance
From the registry record, last updated by the sponsor on 21 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dose Escalation for Stereotactic Cardiac Radiation Therapy of Recurrent Ventricular Tachyarrhythmia - a Multi Center, Phase II Clinical Trial
- ClinicalTrials.gov ID
- NCT05594368
- Acronym / sponsor ID
- DEFT STAR / 2022-00262
- Conditions
- Ventricular Tachycardia
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 15 participants (estimated)
- Lead sponsor
- University of ZurichUniversity, hospital or other
- Study start
- 1 Jul 2022 (actual)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 31 Dec 2028 (estimated)
- First posted
- 26 Oct 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The objective of this study is to demonstrate that higher radiation doses are necessary to induce transmural scar formation which is currently assumed to be the underlying mechanism of successful long-term efficacy of VT treatment and therefore dose-escalation will lead to a significantly reduced long-term VT recurrence rate compared to the currently applied single dose of 25 Gy.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- The study is designed as a one arm, multi-center dose escalation trial employing the i3+3 design.
| Arm | Type | Receives |
|---|---|---|
| Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT) | Experimental | Device: Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Patients with structural heart disease, in particular ischemic and non-ischemic cardiomyopathy: Implanted ICD and/or CRT-D. Prior ≥1 failed catheter ablation (with endocardial ± epicardial approach based on the substrate location and the ECG morphology of clinical VTs) procedure to control sustained monomorphic VT using currently recommended mapping and ablation techniques,2 or patients in whom ablation is not feasible. Reasons for lack of epicardial ablation and non-feasibility of catheter ablation must be specified. Sustained VT recurrence after catheter ablation on optimised antiarrhythmic medication.
- Age ≥18 years. IRB-approved, written informed consent must be provided
Key exclusion criteria (3 listed)
- Patients with only premature ventricular contractions.
- Acute myocardial infarction; Primary electrical disease (channelopathy); Reversible and treatable cause (e.g., drug-induced or intoxication) of VT that can be adequately addressed otherwise; A target that cannot be safely and precisely defined based on stereotactic radiotherapy accuracy requirements (e.g., anatomical interference from OARs, overlapping prior radiation therapy to the thoracic region); Pregnancy or breastfeeding; Inability to provide informed consent.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT)Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT) refractory to conventional antiarrhythmic and catheter ablation-based therapy. First patients will be treated with a dose from 25 Gy prescribed to the 65-90% target volume encompassing isodose escalating to a maximum of 32.5 Gy prescribed to the 65-90% isodose. | Device | Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT) |
Primary outcome
safety measured by registered radiation associated adverse events up to 90 days
Time frame: up to 90 days
safety measured by registered radiation associated adverse events
1 secondary outcome
Radiation associated serious adverse event (at least grade 4 or 5 according to CTCAE v5)
Time frame: As assessed at 90 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Aug 2026.
- Derived from this study: PubMed 37941012Kovacs B, Mayinger M, Ehrbar S, Fesslmeier D, Ahmadsei M, Sazgary L, Manka R, Alkadhi H, Ruschitzka F, Duru F, Papachristofilou A, Sticherling C, Blamek S, Golba KS, Guckenberger M, Saguner AM, Andratschke N. Dose escalation for stereotactic arrhythmia radioablation of recurrent ventricular tachyarrhythmia - a phase II clinical trial. Radiat Oncol. 2023 Nov 8;18(1):185. doi: 10.1186/s13014-023-02361-x.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
3 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Dose escalating stereotactic arrhythmia radioablation to treat ventricular tachycardia (VT) in people with Ventricular Tachycardia, run by University of Zurich at 3 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 21 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Switzerland, Czechia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Nicolaus Andratschke, MD (0041 44 255 4238, nicolaus.andratschke@usz.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
safety measured by registered radiation associated adverse events up to 90 days (time frame: up to 90 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05594368, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Aug 2026; AzTrials last refreshed its copy on 8 Nov 2026.