Results of two phase 2 clinical trials testing cabozantinib suggest that anti-angiogenic therapy could be used to treat glioblastomas
Glioblastoma is an aggressive type of brain tumour that affects approximately 74,000 individuals across the world, annually. The current standard of treatment for this tumour type consists of surgical removal of the tumour, accompanied with radiation therapy and chemotherapy.
Despite patients undergoing a rigorous treatment regimen, the rate of tumour recurrence is high. The treatment options for recurrent glioblastoma are limited. One treatment option includes the use of anti-angiogenic therapy.
Glioblastomas are highly vascularised tumours, which means they have an extensive network of blood vessels running through and around them. These blood vessels supply the tumour with the oxygen and nutrients they need to survive, grow and spread.
The blood vessels that grow in and around tumours develop from existing, nearby blood vessels – a process known as angiogenesis.
Anti-angiogenic therapy prevents the formation of these blood vessels or interferes with their proper functioning, thereby cutting off or reducing the tumour's supply of nutrients and oxygen. The lack of energy then prevents the tumour from growing.
Cabozantinib is an anti-angiogenic drug that is currently being investigating as a potential treatment for glioblastoma.
Scientists from multiple research facilities is the United States have conducted two phase 2 trials that tested cabozantinib in patients with no prior history of anti-angiogenic drugs and patients who have been treated with anti-angiogenic therapy.
Only patients with a history of prior anti-angiogenic therapy demonstrated significant increase in progression-free survival. Progression-free survival is the length of time, both during and after treatment that a patient will survive without the tumour growing. Progression-free survival was measured by monitoring tumour growth in patients.
It is important to note that while cabozantinib did demonstrate some activity in preventing tumour growth, it was modest and further trials to assess this drug are required.