Priority Review Granted; User Fee Goal Date Set for June 23, 2020

NEWTON, MA, USA I February 19, 2020 I Karyopharm Therapeutics Inc. (Nasdaq:KPTI), an oncology-focused pharmaceutical company, today announced that the U.S. Food and Drug Administration (FDA) has accepted for filing its supplemental New Drug Application (sNDA) seeking accelerated approval for oral XPOVIO® (selinexor) tablets, the Company’s first-in-class, Selective Inhibitor of Nuclear Export (SINE) compound, for the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma (RR DLBCL), not otherwise specified, who have received at least two prior therapies. The FDA also granted Karyopharm’s request for Priority Review and assigned a user fee goal date of June 23, 2020 under the Prescription Drug User-Fee Act (PDUFA).

“We look forward to supporting the FDA through the review process for our second NDA for XPOVIO as there remains significant unmet medical need for patients whose DLBCL has relapsed or is refractory to multiple drug therapies,” said Sharon Shacham, PhD, MBA, Founder, President and Chief Scientific Officer of Karyopharm. “This regulatory milestone for XPOVIO represents another important step towards bringing a novel, oral treatment option with a unique mechanism of action to patients and families in need.”

Provided marketing approval is granted by the FDA, Karyopharm plans to commercialize XPOVIO in the U.S. in this second indication by mid-2020. The Company also expects to submit a Marketing Authorization Application to the European Medicines Agency in 2020 requesting conditional approval for XPOVIO in this same indication.

Priority Review is granted by the FDA to drugs that, if approved, would provide significant improvements in the safety or effectiveness of the treatment, diagnosis, or prevention of a serious condition when compared to standard applications. XPOVIO has received both Orphan Drug and Fast Track designations from the FDA for the treatment for patients with relapsed or refractory DLBCL.

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. In addition to receiving 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 adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL). Selinexor has received Fast Track and Orphan designation from the FDA for the patient population evaluated in the SADAL study. 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), as a potential backbone therapy in combination with approved 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.

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 Therapeutics