Karyopharm has announced positive top-line results from the randomised Phase III BOSTON study of Xpovio (selinexor).

In the trial, the drug in combination with once-weekly Velcade (bortezomib) and low-dose dexamethasone (SVd) met its primary endpoint of a statistically significant increase in progression-free survival (PFS) compared to standard twice-weekly Velcade plus low-dose dexamethasone (Vd).

Tested in patients with multiple myeloma who have received one to three prior lines of therapy, the outcome showed that the median PFS in the SVd arm was 13.93 months compared to 9.46 months in the Vd arm, representing a 4.47 month (47%) increase in median progression-free survival.

Further to the findings, there were no new safety signals on the SVd arm and there was no imbalance in deaths between the two arms in the study.

The company is “thrilled to report these highly significant top-line results from the BOSTON study, the first randomised Phase III trial to demonstrate clinically and statistically significant activity of once-weekly Xpovio in combination with a current standard of care treatment in patients with myeloma after one to three prior therapies,” said Sharon Shacham, president and chief scientific officer of Karyopharm.

Sharon continued, “We plan to submit the full data set for presentations at upcoming medical meetings to share the results with the medical community. We also intend to submit these data as quickly as possible to the US Food and Drug Administration (FDA) as part of a supplemental New Drug Application seeking to expand the approved indication for Xpovio into second line treatment for patients with relapsed or refractory multiple myeloma. If approved, the SVd regimen would be the first and only FDA-approved combination drug regimen that includes once-weekly Velcade therapy for relapsed myeloma.”

Multiple myeloma is a cancer that forms in plasma cells, and causes cancer cells to accumulate in the bone marrow, where they crowd out healthy blood cells. Despite recent therapeutic advances, there is currently no cure and most patients’ disease will typically progress following treatment with currently available therapies.