Treatment of Brain AVMs (TOBAS) Study (TOBAS)
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ClinicalTrials.gov Identifier: NCT02098252 |
Recruitment Status :
Recruiting
First Posted : March 27, 2014
Last Update Posted : June 10, 2022
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The objectives of this study and registry are to offer the best management possible for patients with brain arteriovenous malformations (AVMs) (ruptured or unruptured) in terms of long-term outcomes, despite the presence of uncertainty. Management may include interventional therapy (with endovascular procedures, neurosurgery, or radiotherapy, alone or in combination) or conservative management.
The trial has been designed to test a) whether medical management or interventional therapy will reduce the risk of death or debilitating stroke (due to hemorrhage or infarction) by an absolute magnitude of about 15% (over 10 years) for unruptured AVMs (from 30% to 15%); and, b) to test if endovascular treatment can improve the safety and efficacy of surgery or radiation therapy by at least 10% (80% to 90%).
As for the nested trial on the role of embolization in the treatment of Brain AVMs by other means: the pre-surgical or pre-radiosurgery embolization of cerebral AVMs can decrease the number of treatment failures from 20% to 10%. In addition,embolization of cerebral AVMs can be accomplished with an acceptable risk, defined as permanent disabling neurological complications of 8%.
Condition or disease | Intervention/treatment | Phase |
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Unruptured Brain Arteriovenous Malformation Ruptured Brain Arteriovenous Malformation Arteriovenous Malformations AVM BAVM | Procedure: Neurosurgery Radiation: Radiation therapy Procedure: Embolization | Not Applicable |

Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 1000 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | Treatment of Brain AVMs (TOBAS) Study: A Randomized Controlled Trial and Registry |
Study Start Date : | May 2014 |
Estimated Primary Completion Date : | January 2035 |
Estimated Study Completion Date : | January 2036 |
Arm | Intervention/treatment |
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Active Comparator: Interventional therapy
Interventional therapies include: neurosurgery (surgical resection when the lesion is considered by a multidisciplinary team to be safely 'operable'); radiation therapy (when the AVM is smaller than 3 cm, and considered to not be safely 'operable'); radiosurgery, alone or in combination, with or without endovascular procedure; curative embolization (when the lesion is considered curable by embolization). Patients with AVMs that the multidisciplinary team judges could potentially benefit from endovascular treatment prior to surgical resection or radiation therapy will then also be pre-randomly allocated to embolization or to no embolization. |
Procedure: Neurosurgery
Surgical resection to be used when the lesion is considered by a multidisciplinary team to be safely 'operable'. Radiation: Radiation therapy when the AVM is smaller than 3 cm, and considered to not be safely 'operable'. Procedure: Embolization Curative embolization, when the lesion is considered curable by embolization. |
No Intervention: Conservative management (medical management)
The conservative, or medical management arm, involves pharmacological therapy as deemed appropriate for medical symptoms as determined by the treating investigator. Should patients in the conservative management arm develop hemorrhage or infarction related to their AVM, they then potentially become candidates for interventional therapy.
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- composite event of death from any cause or disabling stroke [ Time Frame: up to 10 years post-treatment (or randomization) ]death or disabling stroke due to hemorrhage or infarction as revealed by imaging and resulting in mRS >2.
- occurrence of any neurological event [ Time Frame: within 10 years following treatment (or after randomization) ]
- Permanent disabling peri-operative complications [ Time Frame: within 31 days post-treatment ]The incidence of permanent (more than 3 months) disabling (mRS >2) peri-operative (within 31 days) complications

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Ages Eligible for Study: | 5 Years and older (Child, Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Any patient with a brain AVM
Exclusion Criteria:
- Hemorrhagic presentation with mass effect requiring surgical management. In these cases, if a residual AVM is found after the initial surgery, the patient could then be a candidate for TOBAS.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02098252
Contact: Jean Raymond, MD | 514-890-8000 ext 27235 | jraymond.nri@gmail.com | |
Contact: Tim Darsaut, MD | 780-407-1440 | tdarsaut@ualberta.ca |

Principal Investigator: | Jean Raymond, MD | CHUM-Montreal |
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Centre hospitalier de l'Université de Montréal (CHUM) |
ClinicalTrials.gov Identifier: | NCT02098252 |
Other Study ID Numbers: |
13.315 |
First Posted: | March 27, 2014 Key Record Dates |
Last Update Posted: | June 10, 2022 |
Last Verified: | July 2021 |
brain arteriovenous malformation Arteriovenous Malformations AVM BAVM Stroke Intracranial Hemorrhage |
Congenital Abnormalities Aneurysm Vascular Malformations Cardiovascular Abnormalities Cardiovascular Diseases Vascular Diseases |
Hemangioma Arteriovenous Malformations Congenital Abnormalities Vascular Malformations Cardiovascular Abnormalities |
Cardiovascular Diseases Vascular Diseases Neoplasms, Vascular Tissue Neoplasms by Histologic Type Neoplasms |