Karyopharm Therapeutics: Karyopharm Therapeutics Inc.: Karyopharm Reports Fourth Quarter and Full Year 2024 Financial Results, Announces Update to Phase 3 XPORT-EC-042 Trial and Highlights Recent Company Progress

- Total Revenue of $145 Million and U.S. XPOVIO® (selinexor) Net Product Revenue of $113 Million for Full Year 2024 - - Top-Line Data Readout from Phase 3 SENTRY Trial Evaluating Selinexor in Combination with Ruxolitinib in Patients with JAKi-Naïve Myelofibrosis Anticipated in 2H 2025; Company on Track to Complete Enrollment in 1H 2025 - - Company Announces Update to Phase 3 XPORT-EC-042 Trial of Selinexor as Maintenance Therapy in Advanced or Recurrent TP53 Wild-Type Endometrial Cancer. Following Dialogue with the FDA Regarding the Evolving Treatment Landscape, Trial to Focus Enrollment on Patients with Either pMMR Tumors or Patients with dMMR Tumors that are Medically Ineligible for Checkpoint Inhibitors. Increasing Sample Size to 276; Top-Line Data Now Expected in Mid-2026 - - Company Provides Full-Year 2025 Total Revenue Guidance of $140 Million to $155 Million, Including U.S. XPOVIO Net Product Revenue Guidance of $115 Million to $130 Million - - Conference Call Scheduled for Today at 8:00 a.m. ET - NEWTON, Mass., Feb. 19, 2025 /PRNewswire/ -- Karyopharm Therapeutics Inc. (Nasdaq: KPTI), a commercial-stage pharmaceutical company pioneering novel cancer therapies, today reported financial results for the fourth quarter and full year ended December 31, 2024. In addition, Karyopharm highlighted select corporate milestones and provided an overview of its key clinical development programs. "In 2025, our teams remain focused on the transformative opportunity to redefine the standard of care in myelofibrosis, with top-line data from our Phase 3 SENTRY trial evaluating selinexor in combination with ruxolitinib on-track for the second half of 2025. We look forward to completing enrollment of our SENTRY trial in the first half of this year and leveraging our demonstrated commercialization capabilities in multiple myeloma to support a rapid launch, subject to approval," said Richard Paulson, President and Chief Executive Officer of Karyopharm. "In endometrial cancer, today we announced our updated plans for our Phase 3 trial and intend to primarily focus on the TP53 wild-type pMMR population, which represents approximately 50% of all women with endometrial cancer, and expect to share top-line data in mid-2026." Fourth Quarter 2024 and Recent Highlights XPOVIO Commercial Performance Achieved U.S. net product revenue for the year ended December 31, 2024 of $113 million, compared to $112 million for the year ended December 31, 2023. U.S. net product revenue for the fourth quarter of 2024 was $29 million, compared to $25 million for the fourth quarter of 2023. Demand for XPOVIO was consistent in 2024 versus 2023, with demand growth in the second half of 2024 in both the community setting, which represents approximately 60% of XPOVIO net product revenue, and the academic setting, offsetting a decline in demand in the first half of the year due to an intensified competitive landscape. XPOVIO net product revenue was impacted year-over-year by higher gross-to-net adjustments in 2024, driven primarily by increased 340B discounts and Medicare rebates. Expanded global patient access for selinexor in 2024 with favorable reimbursement decisions in the United Kingdom, France, Italy, China and South Korea and additional regulatory approvals in UAE, Kuwait, China, Malaysia, Turkey, Thailand, and South Korea in various indications, increasing the number of countries where selinexor is now approved in more than 45 countries. Research and Development (R&D) Highlights Myelofibrosis Updated the co-primary endpoint in the Phase 3 SENTRY trial (XPORT-MF-034; NCT04562389) to absolute mean change in total symptom score (Abs-TSS) following alignment with the U.S. Food and Drug Administration (FDA) and proactively increased the total sample size to approximately 350 patients to further increase the statistical powering. Abs-TSS measures the average improvement in symptom scores over 24 weeks relative to the baseline symptom score. Abs-TSS is viewed by many key opinion leaders (KOLs) and patient advocacy organizations as a more accurate assessment of symptom improvement in head-to-head clinical trials, such as SENTRY which is evaluating selinexor in combination with ruxolitinib in patients with JAK inhibitor (JAKi) naïve myelofibrosis versus ruxolitinib alone. Spleen volume reduction =35% (SVR35) at week 24 remains the other co-primary endpoint. These two co-primary endpoints will be tested sequentially starting with SVR35 followed by Abs-TSS. Hosted an investor event with leading KOLs in October 2024 to discuss the change in the co-primary endpoint in the Phase 3 SENTRY trial to Abs-TSS and highlight the strength of the data from the Company's Phase 1 trial in myelofibrosis. Data from the Company's Phase 1 trial, evaluating the combination of selinexor 60 mg plus ruxolitinib in JAKi naïve myelofibrosis patients, demonstrated that 79% of patients in the intent to treat population (n=14) achieved SVR35 and an average Abs-TSS improvement of 18.5 points in the efficacy evaluable population (n=9), at week 24 relative to baseline. Acknowledging the small sample size, these data suggest that the combination is favorable compared to historical ruxolitinib monotherapy data which indicates that less than half of patients achieve SVR35 and an Abs-TSS improvement of 11 to 14 points 1 . As of the most recent data cut off, the safety profile remained consistent and no new safety signals were identified. The Company continues to enroll patients into the 60 mg cohort of the Phase 2 SENTRY-2 trial of selinexor monotherapy in JAKi naïve patients with moderate thrombocytopenia (XPORT-MF-044; NCT05980806). 1 Phase 3 MANIFEST trial. Rampal R, et al. ASH 2023. Oral 628; Phase 3 TRANSFORM-1 trial Pemmaraju N, et al. ASH 2023 abstract 620. Endometrial Cancer The Company is modifying the design of its Phase 3 XPORT-EC-042 trial evaluating selinexor as a maintenance-only therapy following systemic therapy versus placebo in patients with TP53 wild-type advanced or recurrent endometrial cancer. In late 2024 and early 2025, the Company engaged in communications with the FDA regarding the design adequacy of XPORT-EC-042 given the changing standard of care in endometrial cancer, particularly the approval of checkpoint inhibitors for patients with advanced or recurrent endometrial cancer regardless of mismatch repair status. In light of the FDA's acknowledgement that the magnitude of benefit achieved from checkpoint inhibitors is less for patients with pMMR tumors than patients with dMMR tumors, consistent with the biology and mechanism of action of checkpoint inhibitors, the Company's modifications include defining two patient populations for which the primary endpoint of progression free survival (PFS), tested sequentially, and key secondary endpoint of overall survival (OS) will be evaluated: a modified intent to treat population (mITT) that will include patients with: TP53 wild-type tumors with proficient mismatch repair status (pMMR); or, TP53 wild-type tumors with deficient mismatch repair status (dMMR), who are medically ineligible to receive checkpoint inhibitors. the trial's original intent to treat (ITT) population, which will include all patients enrolled in the trial whose tumors are TP53 wild-type, regardless of MMR status. The Company is increasing the trial sample size from 220 patients to approximately 276 patients, to ensure that the mITT population includes approximately 220 patients who are either: a) TP53 wild-type pMMR or b) TP53 wild-type dMMR and medically ineligible to receive a checkpoint inhibitor. The increase in sample size maintains sufficient power for the primary endpoint of PFS in the mITT population. To date, approximately 80% of patients enrolled meet the new eligibility definition for the mITT population. The proposed modifications are intended to address certain of the FDA's feedback regarding the evolving treatment landscape, including the approval of multiple checkpoint inhibitors for advanced/recurrent endometrial cancer patients with pMMR and/or dMMR tumors in 2023 and 2024. Enrollment continues in the XPORT-EC-042 trial and, depending on the strength of the data, the Company intends to pursue regulatory approval. As a result of the proposed modifications, the Company now expects topline data in mid-2026. Multiple Myeloma Completed enrollment of the Phase 3 XPORT-MM-031 trial (EMN29; NCT05028348) of approximately 120 patients, leveraging the data published on selinexor 40 mg, pomalidomide and dexamethasone (SPd40) in 2024. The Phase 3 XPORT-MM-031 trial is being conducted in collaboration with the European Myeloma Network and is evaluating the all-oral combination SPd40 in patients with previously treated multiple myeloma who received an anti-CD38 in their immediate prior line of therapy. Pending ongoing engagement with regulatory agencies on the updated protocol and statistical plan, the Company intends to provide an update on this trial. Anticipated Catalysts and Operational Objectives in 2025 Myelofibrosis Announce completion of enrollment of the Phase 3 SENTRY trial evaluating selinexor in combination with ruxolitinib in JAKi naive myelofibrosis patients in 1H 2025. Report preliminary data on a subset of participants in the 60 mg cohort from the Phase 2 SENTRY-2 trial evaluating selinexor as a monotherapy in patients with JAKi naïve myelofibrosis with moderate thrombocytopenia in 1H 2025. Report top-line results from the Phase 3 SENTRY trial in 2H 2025. Multiple Myeloma Maintain the Company's commercial foundation in the competitive multiple myeloma marketplace and drive increased XPOVIO revenues. Continue global launches and reimbursement approvals for selinexor by partners in ex-U.S. territories. Continue to follow patients that are enrolled in the Phase 3 XPORT-MM-031 (EMN29) trial. Pending ongoing engagement with regulatory agencies on the updated protocol and statistical plan, the Company intends to provide an update on this