Immunotherapy Update: New Study Suggests Immunotherapy May Be Useful For Some Types Of Brain Cancer

Glioblastoma patients usually need their tumor to be removed. In this study, researchers tested the effects of treating patients with a drug called Keytruda before the removal. Keytruda is an immunotherapy drug also known as Pembrolizumab, which means it unleashes the body’s immune system and against the cancer.

The report says that patients who had the treatment before their surgery survived an average of 417 days — nearly double the historic average for the deadly disease. The drug is part of a class of cancer treatments called checkpoint inhibitors, which unleash the immune system to attack cancer cells, according to coverage in Bloomberg Technology. Ever since the breakthrough invention of immunotherapy — using the body’s immune system to fight cancer — researchers have been doing a lot of testing on its different applications.

The findings provide some useful new information. “While prior studies have provided limited evidence to support the use of immune-activating checkpoint inhibitors in patients with glioblastoma,” says Dr. Erik P. Sulman, MD, PhD, co-director of the Brain Tumor Center at NYU Langone's Perlmutter Cancer Center, “a new report by the Ivy Foundation Early Phase Clinical Trial Consortium (Cloughesy TF et al Nature Feb 11, 2019) suggests that the use of the immune checkpoint drug pembrolizumab given prior to surgery may improve survival.”

“Pembrolizumab is an antibody the binds a protein on specific immune cells to activate them to attack the tumor,” says Dr. Sulman. “In this randomized study of patients with resectable, recurrent tumors, median survival for those who received pembrolizumab before surgery was 13.7 months compared to 7.5 months for those that received the drug only after surgery.” “Resectable” tumors are tumors that can be completely or partially removed, so all of the patients were people who were going to have their tumors surgically taken out.

“The resected tumors were evaluated extensively and suggested that the most effective immune response was initiated when the tumor was present, but did not occur as effectively once the majority of the tumor was removed,” says Dr. Sulman, so the immune system will actually kick in to its fullest if the immune-activating drug is administered before the tumor is taken out.

“In contrast to other tumors for which immune checkpoint inhibitors are used, the use of low dose dexamethasone did not appear to negate the benefit of pembrolizumab,” he says, so pembrolizumab won’t work any less if that drug is present.

“A non-randomized trial by another group in the same issue treated glioblastoma patients with nivolumab, which also blocks the same receptor as pembrolizumab, prior to surgery and found similar immune activation upon analysis of resected tumors,” according to Dr. Sulman, so similar drugs are also being tested to positive results.

“Both trials not only provide support for larger studies of other immune checkpoint inhibitors in patients with glioblastoma,” he continues, “they also indicate that these treatments may find the greatest benefit if given before surgical resection, when the tumor is still present to interact with the environment surrounded it and activate the immune system. In addition, the ability to comprehensively study the treated tumors after surgery provides invaluable data to support the mechanism of action of these treatments and how they may be further enhanced.”

Glioblastoma is a very difficult diagnosis. “Overall, the, the two-year survival rate is very low, although there is a tail meaning that if we look at survival curves, there’s a, there’s a small percentage of patients that are living past what we would consider to be typical for a diagnosis with glioblastoma,” says Dr. Melanie Hayden Gephart is a brain tumor neurosurgeon at Stanford University Medical Center. “At this point, I don’t feel like we have good, durable cures, but we have well-tolerated treatments that can improve the patients’ quality of life and give them, also, additional time.”

“The location is very important. And that progresses from grade one to two, three, and four, again, each time becoming progressively more aggressive, and also looking more abnormal underneath the microscope until a grade four, which is called a glioblastoma, which is the most malignant type of primary brain tumor,” she says.

“Depending upon the location, grade one you would think is potentially a benign tumor,” says Dr. Hayden. “The challenge with brain tumors, though, is that a benign tumor that’s in a very, a very tricky location for example, within the patient’s primary language area, the area that they use to formulate and understand speech, or within the vision pathway it doesn’t have a benign effect to the patient.”

 

 

 

 

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