NEWTON, MA, USA I April 20, 2020 I Karyopharm Therapeutics Inc. (Nasdaq:KPTI) today announced dosing of the first patient in a randomized Phase 2 clinical study evaluating low dose oral selinexor in hospitalized patients with severe COVID-19. This global study is expected to enroll approximately 230 patients at clinical sites in the U.S., Europe, and Israel.  Selinexor is an oral selective inhibitor of nuclear export (SINE) compound which blocks the cellular protein XPO1 which is involved in both the replication of SARS-CoV-2, the virus that causes COVID-19, and in the inflammatory response to the virus.

The randomized, multi-center, placebo-controlled Phase 2 study (XPORT-CoV-1001/NCT04349098) of low dose selinexor is designed to assess the activity and safety of 20mg of selinexor given orally three times a week for two weeks. Patients tolerating therapy well and experiencing clinical benefit may be eligible to continue treatment for an additional two weeks at the discretion of the treating physician.  The primary endpoint of the study is time to clinical improvement based on improvement in the Ordinal Scale, consistent with the COVID-19 trial recommendations by the World Health Organization and the U.S. Food and Drug Administration (FDA). Additional secondary endpoints in the study include the overall death rate at day 28 as well as the rate of, and time to, mechanical ventilation.

“In less than two weeks since announcing our intention to study selinexor in patients with severe COVID-19, we have quickly mobilized our team to activate clinical trial sites across the globe and are proud to announce the dosing of the first patient in our randomized study,” said Sharon Shacham, PhD, MBA, President and Chief Scientific Officer of Karyopharm. “This important milestone marks the first study of an XPO1 inhibitor in patients with severe viral infections. We remain highly encouraged by the potential anti-viral and anti-inflammatory activity of XPO1 inhibition with selinexor and look forward to working with the medical community of regulators, treating physicians and patients on advancing this important study as quickly as possible.” 

SINE compounds have been identified as having the potential to interfere with key host protein interactions with influenza, RSV and other viruses including SARS-CoV-2.1 Furthermore, XPO1 (also called CRM1) was identified as one of the host proteins with the highest number of functional connections with SARS-CoV proteins.2  Finally, SINE compounds, including selinexor, have demonstrated potent anti-inflammatory activity through the inhibition of Nuclear Factor kB (NF-kB), leading to reductions in cytokines such as IL6, IL1, IFNg and others in a variety of models, which may be particularly beneficial to hospitalized patients with COVID-19 and other severe viral infections.

“In my laboratory, we have now used two different approaches to investigate selinexor’s ability to inhibit the viral propagation of the SARS-CoV-2 virus in Vero cells, which are monkey cells commonly used in modeling human viral infections. In our first experiment, with the assistance of Jackelyn Murray in my lab, we demonstrated that selinexor inhibited the production of new virus by 90% at a low concentration (100 nM) from cells that were already infected with SARS-CoV2.  This is very exciting as low oral doses of selinexor are expected to deliver levels over 300 nM.  In the second experiment, we showed that even lower levels of selinexor, only 10nM, could reduce the ability of the virus to infect new cells by about 99%. I am highly encouraged by these results and thrilled to see how quickly Karyopharm is able to test these scientific findings in patients so dramatically impacted by the current COVID-19 pandemic,” said Ralph Tripp, PhD, a Georgia Research Alliance Eminent Scholar and Professor in the Department of Infectious Diseases in the College of Veterinary Medicine at the University of Georgia.”

Selinexor, marketed as XPOVIO®, is currently approved at higher doses by the FDA as a treatment for patients with relapsed or refractory multiple myeloma. Selinexor is currently the only XPO1 inhibitor approved for commercial use by the FDA and has been extensively tested in clinical trials across numerous cancer indications worldwide since 2012. Karyopharm has sufficient supply of selinexor for current and expected commercial patients with multiple myeloma, for ongoing clinical trials in patients with various cancers, as well as for this study in patients with COVID-19. 

About XPOVIO® (selinexor)

XPOVIO is a first-in-class, oral Selective Inhibitor of Nuclear Export (SINE) compound. XPOVIO functions by selectively binding to and inhibiting the nuclear export protein exportin 1 (XPO1, also called CRM1). XPOVIO blocks the nuclear export of tumor suppressor, growth regulatory and anti-inflammatory proteins, leading to accumulation of these proteins in the nucleus and enhancing their anti-cancer activity in the cell. The forced nuclear retention of these proteins can counteract a multitude of the oncogenic pathways that, unchecked, allow cancer cells with severe DNA damage to continue to grow and divide in an unrestrained fashion. Karyopharm received accelerated U.S. Food and Drug Administration (FDA) approval of XPOVIO in July 2019 in combination with dexamethasone for the treatment of adult patients with relapsed refractory multiple myeloma (RRMM) who have received at least four prior therapies and whose disease is refractory to at least two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody. Karyopharm has also submitted a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) with a request for conditional approval of selinexor.  A supplemental New Drug Application was recently accepted by the FDA seeking accelerated approval for selinexor as a new treatment for patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), and selinexor has received Fast Track and Orphan designation and Priority Review from the FDA with a scheduled PDUFA date of June 23, 2020 for this patient population. Selinexor is also being evaluated in several other mid-and later-phase clinical trials across multiple cancer indications, including in multiple myeloma in a pivotal, randomized Phase 3 study in combination with Velcade® (bortezomib) and low-dose dexamethasone (BOSTON), for which Karyopharm announced positive top-line results in March 2020.  Additional, ongoing trials for selinexor include as a potential backbone therapy in combination with approved myeloma therapies (STOMP), in liposarcoma (SEAL) and in endometrial cancer (SIENDO), among others. Additional Phase 1, Phase 2 and Phase 3 studies are ongoing or currently planned, including multiple studies in combination with approved therapies in a variety of tumor types to further inform Karyopharm’s clinical development priorities for selinexor. Additional clinical trial information for selinexor is available at www.clinicaltrials.gov.

References

1 Gordon, D. et al. A SARS-CoV-2-Human Protein-Protein Interaction Map Reveals Drug Targets and Potential Drug Repurposing. bioRxiv. 2020. 03.22.002386. https://doi.org/10.1101/2020.03.22.002386

2 Zhou, Y. et al. Network-based drug repurposing for novel coronavirus 2019-nCoV/SARS-CoV-2. Cell Discovery. 2020. 6:14. https://doi.org/10.1038/s41421-020-0153-3

About Karyopharm Therapeutics

Karyopharm Therapeutics Inc. (Nasdaq: KPTI) is an oncology-focused pharmaceutical company dedicated to the discovery, development, and commercialization of novel first-in-class drugs directed against nuclear export and related targets for the treatment of cancer and other major diseases. Karyopharm’s Selective Inhibitor of Nuclear Export (SINE) compounds function by binding with and inhibiting the nuclear export protein XPO1 (or CRM1). Karyopharm’s lead compound, XPOVIO® (selinexor), received accelerated approval from the U.S. Food and Drug Administration (FDA) in July 2019 in combination with dexamethasone as a treatment for patients with heavily pretreated multiple myeloma. A Marketing Authorization Application for selinexor is also currently under review by the European Medicines Agency. A supplemental New Drug Application was recently accepted by the FDA seeking accelerated approval for selinexor as a new treatment for adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL). In addition to single-agent and combination activity against a variety of human cancers, SINE compounds have also shown biological activity in models of neurodegeneration, inflammation, autoimmune disease, certain viruses and wound-healing. Karyopharm has several investigational programs in clinical or preclinical development. For more information, please visit www.karyopharm.com

SOURCE: Karyopharm