Benzinga | Mar 29, 2021 12:53PM EDT

Karyopharm Shares Spike Higher After Announcement Co. Receives Conditional Market Authorization From The European Commission For NEXPOVIO (selinexor)

Karyopharm Therapeutics Inc. (NASDAQ:KPTI), a commercial-stage pharmaceutical company pioneering novel cancer therapies, today announced that the European Commission (EC) has granted conditional marketing authorization for NEXPOVIO (selinexor), the Company's first-in-class, oral Selective Inhibitor of Nuclear Export (SINE) medicine, in combination with dexamethasone for the treatment of multiple myeloma in adult patients who have received at least four prior therapies and whose disease is refractory to at least two proteasome inhibitors, two immunomodulatory agents, and an anti-CD38 monoclonal antibody, and who have demonstrated disease progression on the last therapy.

Conditional marketing authorization is supported by data from the positive Phase 2b STORM study, which evaluated selinexor in adult patients with heavily pretreated, triple class refractory multiple myeloma and was published in the New England Journal of Medicine (Chari, et al.) in August 2019. Under the provisions of conditional approval by the EC, continued authorization for this indication is contingent upon verification and description of clinical benefit in a confirmatory trial and is subject to additional monitoring. An EC marketing authorization through the centralized procedure (CP) is valid in all 27 European Union (EU) member countries, as well as the European Economic Area (EEA) countries of Iceland, Liechtenstein and Norway.

"NEXPOVIO represents the first and only nuclear export inhibitor authorized in Europe and we are delighted to bring this new treatment option to eligible adult patients with heavily pretreated multiple myeloma. Despite advancements in the treatment of multiple myeloma, most adult patients will eventually relapse and develop disease that is refractory to all authorized therapies, further highlighting the urgent need for new therapies with novel mechanism of actions like NEXPOVIO," said Sharon Shacham, PhD, MBA, Founder, President and Chief Scientific Officer of Karyopharm. "Our first product authorization in Europe could not have been possible without the dedication of the patients, caregivers, physicians and Karyopharm employees involved in the clinical development of NEXPOVIO over the last 13 years."

"Today's authorization is an important step forward in the international expansion of selinexor, now with marketing authorization for use in Europe, Israel and the U.S.," said Michael G. Kauffman, MD, PhD, Chief Executive Officer of Karyopharm. "We are committed to making NEXPOVIO available in Europe initially through a Named Patient Program and are on track to submit a second European regulatory filing in April based on the positive data from the Phase 3 BOSTON study to potentially further expand NEXPOVIO to eligible adult patients in need of new treatment options."

About the Phase 2b STORM Pivotal Trial

The Phase 2b STORM trial (Selinexor Treatment of Refractory Myeloma) was an international, multi-center, single-arm, open-label study which enrolled 123 adult patients (Part 2 of the trial) with heavily pretreated, triple class refractory multiple myeloma. Adult patients in the trial had a median of seven previous therapeutic regimens, including a median of 10 unique anti-myeloma agents.

For the study's primary endpoint, oral selinexor achieved an overall response rate of 26% (95% confidence interval [CI], 19, 35) and the trial therefore met its primary endpoint (n=123). Minimal response per IMWG criteria was observed in 16 (13%) patients and 48 patients (39%) had stable disease. All responses were adjudicated by an Independent Review Committee. Among the modified intent to treat population enrolled in STORM Part 2, eighty--three (83) patients had relapse and/or refractory multiple myeloma that was refractory to two proteasome inhibitors (bortezomib, carfilzomib), two immunomodulators (lenalidomide, pomalidomide) and an anti-CD38 monoclonal antibody (daratumumab), the efficacy analysis was based on these 83 patients. A secondary efficacy endpoint included overall survival (OS), defined as the duration from start of study treatment to death due to any cause. The median OS was 8.6 months in the total population (n=123) studied and 15.6 months in adult patients who had a minimal response or better.

Karyopharm's request for conditional authorization in Europe was based upon the same patient population that served as the basis for XPOVIO's accelerated FDA approval in the U.S. The overall response rate in this patient population (n=83) was 25.3 % (95% confidence interval [CI], 16.4, 36).

The most common adverse reactions in the STORM trial (?20%) were thrombocytopenia, fatigue, nausea, anemia, decreased appetite, decreased weight, diarrhea, vomiting, hyponatremia, neutropenia, leukopenia, constipation, dyspnea and upper respiratory tract infection. In the STORM trial, fatal adverse reactions occurred in 9% of adult patients. Serious adverse reactions occurred in 58% of adult patients. Treatment discontinuation rate due to adverse reactions was 27%.