Neuroscience News recently published an intriguing article suggesting that letrozole, a drug developed to treat breast cancer, has the potential to treat brain tumors.
The discovery began with a question about letrozole and its effectiveness against glioblastoma. It then led to ten years of research resulting in a clinical trial after which the team received $1.9 million in funding from the NIH that was used to investigate an effective treatment for glioblastoma. About twelve thousand cases of GBM, usually stage 4, are reported in the United States every year.
Treatment for GBM
The current treatment for GBM includes surgery to remove a substantial part of the tumor plus chemotherapy and radiation. In most cases, the patient is unaware of the tumor until it has become substantially enlarged and symptoms emerge. GBM is so aggressive that most patients do not survive longer than fifteen months after they have been diagnosed as the tumors oft times reoccur or they manage to resist treatment.
About Letrozole
In 2001 the FDA approved letrozole to treat women who have been diagnosed with breast cancer. Letrozole targets the aromatase enzyme that is found in breast cancer cells and is responsible for the growth of cancer.
In 2012 Pankaj B. Desai Ph.D. and his team questioned whether the aromatase enzyme could be effective in GBM and whether letrozole would work just as effectively in GBM as it does in breast cancer.
Much of this speculation was based on the presence of the aromatase enzyme in cell lines of brain tumors. After further testing, the team found unusually high amounts of aromatase in brain tumors that they obtained from the University’s tumor bank.
Although this bodes positive for letrozole, the researchers still carry the burden of validating the drug’s effectiveness in targeting brain tumors.
About the Blood Brain Barrier
One substantial obstacle to letrozole’s effect on GBM is known as the blood-brain barrier. It is the brain’s defense mechanism that prevents certain compounds from entering the brain based on their chemical and physical components.
Professor Pankaj Desai, Director of Drug Development at UC, explained that the team chose letrozole above other drug candidates because they believe that it has the best chance of passing through the blood-brain barrier. Professor Desai told Neuroscience News that letrozole has been effective in targeting tumor cells in models of cell culture.
With additional funding from the UC Brain Tumor Center and the Cancer Center, the team proceeded to Phase One to determine an appropriate letrozole dosage for the treatment of glioblastomas. Dr. Trisha Draper, phase 1 oncology trial expert led the trial. Dr. Draper was joined by neurosurgeons and neurologists.
Halfway There
Professor Desai stated that the trial is close to completion. He added with certainty that results indicate letrozole is able to reach tissue in brain tumors safely.
As aforesaid, GBM is an aggressive and complicated type of brain cancer. Letrozole is promising but is not entirely curative. Professor Desai indicated that a combination of drugs will no doubt be required to bring about a cure.
Therefore, with the help of NIH/NINDS funding which began on August 1st of this year, the Professor and team will continue to research combining letrozole and various chemotherapy compounds.
Professor Desai added that attempting to find a cure for GBM is a major endeavor, but they hope to find the key to making it work.
