- Karyopharm Therapeutics, a small Newton, Massachusetts-based pharma, hopes to file for accelerated approval of its multiple myeloma drug as early as 2018, after Phase 2b trial results showed the drug led to a response in roughly 20% of heavily pretreated patients.
- Karyopharm had announced a week earlier its plans to expand the study by approximately 120 "penta-refractory" patients, or individuals whose cancer had progressed following treatment with five other therapies.
- Top-line results from the expanded trial, which is aimed at supporting a filing for accelerated approval, are expected in early 2018. Karyopharm also plans to initiate a Phase 3 study of the drug, known as selinexor, in combination with Takeda's Velcade and dexamethasone.
Karyopharm's focus on quad-refractory and penta-refractory multiple myeloma patients is indicative of the progress made in developing new treatments for the blood cancer.
The Phase 2b study tested selinexor in patients whose cancer had previously received Takeda's Velcade, Amgen's Kyprolis, and Celgene's Revlimid and Polymast (quad-refractory) and patients whose cancer had become refractory to those four drugs along with Johnson & Johnson's Darzalex (penta-refractory).
Kyprolis, Revlimid, Polymast and Darzalex all received approval for treatment of certain types of multiple myeloma within the last four years. In that time span, Takeda's Ninlaro and Bristol-Myers Squibb's Empliciti have also been approved but were not studied in Karyopharm's trial.
Among the 48 evaluable quad-refractory patients, nearly 21% responded to treatment while one in five of the 30 penta-refractory patients saw a response.
Karyopharm hopes the efficacy of selinexor among penta-refractory patients will help it win accelerated approval— which requires drugmakers to prove a treatment represents a "meaningful therapeutic benefit" over existing treatments. The company doesn't believe there are any other drugs which have shown efficacy in penta-refractory patients.
In order to bolster the results seen in those 38 patients and support an accelerated approval filing, Karyopharm is expanding the Phase 2b study by approximately 120 penta-refactory patients. Top-line data from the new cohort is expected in early 2018.
A Phase 3 study set to start in early 2017 will test the efficacy of selinexor in combination with two other drugs in patients who have received one to three previous treatments.
Karyopharm stock, which had soared higher by 37% on last week's announcement of the expanded trial, fell back by nearly 16% in Tuesday trading.