Experimental treatment shows promise in elimination of brain tumor cells in mice

Johns Hopkins researchers have discovered that treatment with a repurposed FDA-approved drug halted the growth in mice of brain tumor cells taken from adult human patients, and ultimately left no detectable trace of the tumor cells.

The researchers caution that many treatments have cured cancers in mice and then failed in humans. But they are encouraged by the new findings, described online last week in the open-access journal Oncotarget, and want to work quickly to design a clinical trial for humans.

"Usually in the lab, we're happy to see a drug slow down tumor growth," said Alexandra Borodovsky, a graduate student in the Cellular and Molecular Medicine Program at the Johns Hopkins University School of Medicine who performed the experiments. "We never expect tumors to regress, but that is exactly what happened here."

The scientists targeted a mutation in the IDH1 gene first identified in a type of human brain tumors called gliomas by a team of Johns Hopkins cancer researchers in 2008. The mutation was found in 70 to 80 percent of lower-grade and progressive forms of the brain cancer. Despite the growing understanding of IDH1 mutant gliomas, the development of effective therapies has proven challenging, researchers say.

"This therapy has worked amazingly well in these mice," said study leader Gregory J. Riggins, a professor of neurosurgery and oncology at the School of Medicine. "We have spoken with neurosurgeons here, and as soon as possible, we want to start discussing the parameters of a clinical trial to see if this will work in our patients as a follow-up to surgery."

The type of tumor targeted eventually progresses to a subtype of glioblastoma multiform&mdashthe deadliest form of brain cancer—known as progressive or secondary glioblastoma. The tumors arise as a lower-grade glioma and typically are initially treated with surgery alone, but eventually they progress to the more lethal form of tumor.