Karyopharm Therapeutics’ new product, Xpovio to treat multiple myeloma, is the first entry in a class known as selective inhibitor of nuclear export (SINE) drugs, and the FDA approval the company secured for the product earlier this month is quite limited. But one research group sees potential for Xpovio in another cancer type: glioblastoma.
The Ivy Brain Tumor Center at the Phoenix-based Barrow Neurological Institute announced it has formed a partnership with Karyopharm to study Xpovio in adult glioblastoma, a form of brain cancer that has proven particularly difficult to target with drugs. The research will involve testing the drug as part of a combination treatment strategy, according to a statement from the Ivy Brain Tumor Center.
Xpovio works by blocking the nuclear export protein XPO1, which in turn activates proteins that suppress tumors. The Ivy Center’s plan is to test it in tumor cells taken directly from patients. By combining it with other drugs and probing the impact of the cocktails on the cells, researchers there hope to understand the impact on individual patients’ tumors within seven days.
The Karyopharm-partnered research is aimed at developing a “new therapeutic strategy that can be accelerated into the clinic and patients in need,” said Nader Sanai, M.D., director of the Ivy Brain Tumor Center, in the statement.
Xpovio faced a tough road to FDA approval in multiple myeloma. An advisory committee to the agency actually voted against the approval due to safety concerns. The approval is limited to patients who have grown resistant to four other forms of treatment, and it’s dependent upon data from a confirmatory trial.
Still, Karyopharm is dedicated to examining the potential of the drug in other cancers. It is currently running clinical trials of Xpovio in diffuse large B-cell lymphoma, liposarcoma and endometrial cancer, as well as its own phase 2 trial in glioblastoma.
At the recent annual meeting of the American Society of Clinical Oncology, researchers released data from the phase 2 glioblastoma trial, reporting that one-third of the 76 patients in the trial had not experienced a progression of their disease and that the median duration of response was 11 months.
No doubt the need for new approaches to treating glioblastoma is vast, as the field continues to be riddled by failures. In May, AbbVie stopped recruiting patients for its phase 3 trial of depatuxizumab mafodotin in glioblastoma patients with EGFR due to a lack of survival benefit. Even Bristol-Myers Squibb’s immuno-oncology blockbuster Opdivo, which has been approved to treat several other cancers, has not shown a survival benefit in glioblastoma.
Part of the challenge in treating glioblastoma lies in the difficulty of getting drugs into the brain—a problem several academic groups are working to solve. In May, scientists at the University of Wisconsin-Madison and the University of Texas at Austin announced that they developed a new drug delivery system inspired by the jawless sea lamprey, and when they combined it with Johnson & Johnson’s chemotherapy drug Doxil they achieved tumor shrinkage in mouse models of glioblastoma.
University of California, San Francisco spinoff Telo Therapeutics is working with GlaxoSmithKline on drugs that target a genetic mutation in glioblastoma that gives the tumors the power to divide and spread uncontrollably.
The Ivy Brain Tumor’s goal is to try to speed advances into the clinic by testing potential therapies on tumor samples taken from patients who are currently battling glioblastoma—an approach its researchers hope will shed some light on the potential of Karyopharm’s new drug in treating the disease.
“Selinexor exploits a compelling target in glioblastoma patients, which is why we have selected it as the backbone of a new experimental drug cocktail,” Sanai said.