To treat a rare and highly deadly type of brain cancer, glioblastoma, US scientists have developed a new strategy that involves implanting an ultrasound device in the skull and using two chemotherapy drugs, paclitaxel and carboplatin. Preliminary tested, the therapy seems to generate promising results.
Thinking about cancer treatment, the blood-brain barrier is one of the main complicating factors. Developed to protect the organ from toxins and foreign substances, this wall of compacted cells also prevents the arrival of medicines in the region. In this way, most therapies do not trigger the necessary effectiveness to fight tumor cells.
Today, temozolomide is one of the only drugs that can naturally cross the blood-brain barrier. However, researchers from Northwestern University, responsible for the new technique, consider the compound’s effectiveness to be low. In this context, they are testing ways to improve the delivery of chemotherapy drugs to the brain.
How does ultrasound help with cancer treatment?
Still in Phase 2 clinical trials, the treatment is, for now, only planned for glioblastoma patients who have already undergone surgery to remove the original tumor. It is in this procedure that the ultrasound device will be implanted and then begin to be used in the treatment that prevents the brain cancer from coming back.
When the implant is already operative in the patient, doctors inject (intravenously) microbubbles — small spheres of fat filled with gas — into the bloodstream that must reach the vessels of the brain. At this moment, the ultrasound is activated and its sound waves shake the microbubbles, temporarily breaking the blood-brain barrier. Then the drug dose is applied. With free passage, the drugs reach the site affected by the tumor.
Next, see how the entire medication delivery procedure occurs in the human body:
According to preliminary results, brain regions exposed to ultrasound contained about 3.7 times more paclitaxel and 5.9 times more carboplatin. This finding indicates that drug delivery was significantly improved, which may represent an eventual cure — this still needs to be confirmed later.
The interesting thing about the therapy is that the chemotherapy session is done with the patient awake and, in a few hours, he is already discharged. In parallel, the blood-brain barrier is restored within one hour of the procedure.
More oncological studies are needed
For now, only Phase 1 of the study has been published in the scientific journal The Lancet Oncology. In the article, the authors detail the tolerance and safety of the therapy involving exclusively the delivery of the drug paclitaxel. The new stage that provides for the combined use of medications, involving 57 patients, should only be completed in 2025, according to the National Institutes of Health (NIH). At this time, the survival rate of individuals will also be known, which is very low today.
It is worth noting that different research teams are seeking, through different approaches, how to control cases of glioblastoma. For example, scientists at Johns Hopkins University have developed a new gel that combines chemotherapy (cancer drugs) with immunotherapy (monoclonal antibodies) to treat this type of tumor. However, the research is in the pre-clinical stage, being done only with animal models.
Source: The Lancet Oncology, NIH e Northwestern University
