On December 10, 2022, Karyopharm Therapeutics Inc. (the “Company” or “Karyopharm”) presented a poster at the 64th American Society of Hematology (“ASH”) 2022 Annual Meeting and Exposition providing updated results from the Phase 1 portion of its study evaluating the safety and efficacy of once-weekly selinexor in combination with standard dose ruxolitinib in patients with treatment-naïve myelofibrosis (NCT04562389).
The data show that the combination of selinexor with ruxolitinib achieved rapid and sustained spleen responses, encouraging improvements in symptoms and stabilization of hemoglobin levels in patients with treatment-naïve myelofibrosis. As of October 21, 2022, 24 patients had been assigned to either a 40 mg or 60 mg once weekly dose of selinexor, in combination with ruxolitinib 15/20 mg BID (twice daily). At week 24, 92% of efficacy evaluable patients (11 out of 12) demonstrated ≥35% reduction in spleen volume (SVR35). Ongoing reductions in SVR were seen from baseline to week 12 and week 24, with a 45% median reduction at week 12 and a 49% median reduction at week 24. 67% of the evaluable patients for symptom response (4 out of 6) at week 24 achieved ≥50% reduction (TSS50). 57% of transfusion-independent patients (13 out of 23) maintained or improved their hemoglobin levels.
The safety population was comprised of 24 patients, all of whom received at least one dose of selinexor. The most common adverse events (“AEs”) were nausea (75%), anemia (62%) and fatigue (58%), the majority of which were grades 1-2. The most common reported grade 3-4 treatment-emergent AEs were anemia (37%) and thrombocytopenia (21%), both of which were reversible.
Forward-Looking Statements
This current report on Form 8-K contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, that are intended to be covered by the safe harbor created by those sections. Such forward-looking statements include those regarding the ability of selinexor to treat patients with multiple myeloma, myelofibrosis, diffuse large B-cell lymphoma, solid tumors and other diseases and expectations related to the clinical development plans and potential regulatory submissions of selinexor. Such statements are subject to numerous important factors, risks and uncertainties, many of which are beyond Karyopharm’s control, that may cause actual events or results to differ materially from Karyopharm’s current expectations. For example, there can be no guarantee that Karyopharm will successfully commercialize XPOVIO or that any of Karyopharm’s drug candidates, including selinexor and eltanexor, will successfully complete necessary clinical development phases or that development of any of Karyopharm’s drug candidates will continue. Further, there can be no guarantee that any positive developments in the development or commercialization of Karyopharm’s drug candidate portfolio will result in stock price appreciation. Management’s expectations and, therefore, any forward-looking statements in this Current Report on Form 8-K could also be affected by risks and uncertainties relating to a number of other factors, including the following: the risk that the COVID-19 pandemic could disrupt Karyopharm’s business more severely than it currently anticipates, including by negatively impacting sales of XPOVIO, interrupting or delaying research and development efforts, impacting the ability to procure sufficient supply for the development and commercialization of selinexor or other product candidates, delaying ongoing or planned clinical trials, impeding the execution of business plans, planned regulatory milestones and timelines, or inconveniencing patients; the adoption of XPOVIO in the commercial marketplace, the timing and costs involved in commercializing XPOVIO or any of Karyopharm’s drug candidates that receive regulatory approval; the ability to obtain and retain regulatory approval of XPOVIO or any of Karyopharm’s drug candidates that receive regulatory approval; Karyopharm’s results of clinical trials and preclinical studies, including subsequent analysis of existing data and new data received from ongoing and future studies; the content and timing of decisions made by the U.S. Food and Drug Administration and other regulatory authorities, investigational review boards at clinical trial sites and publication review bodies, including with respect to the need for additional clinical studies; the ability of Karyopharm or its third party collaborators or successors in interest to fully perform their respective obligations under the applicable agreement and the potential future financial implications of such agreement; Karyopharm’s ability to enroll patients in its clinical trials; unplanned cash requirements and expenditures; development or regulatory approval of drug candidates by Karyopharm’s competitors for products or product candidates in which Karyopharm is currently commercializing or developing; and Karyopharm’s ability to obtain, maintain and enforce patent and other intellectual property protection for any of its products or product candidates. These and other risks are described under the caption “Risk Factors” in Karyopharm’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2022, which was filed with the Securities and Exchange Commission (“SEC”) on November 3, 2022, and in other filings that Karyopharm may make with the SEC in the future. Any forward-looking statements contained in this Current Report on Form 8-K speak only as of the date hereof, and, except as required by law, Karyopharm expressly disclaims any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.
