Karyopharm Therapeutics Inc. 10-Q

Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations. The following discussion and analysis of our financial condition and results of operations is meant to provide material information relevant to an assessment of the financial condition and results of operations of our company, including an evaluation of the amounts and uncertainties of cash flows from operations and from outside resources, so as to allow investors to better view our company from management’s perspective. You should read the following discussion and analysis of our financial condition and results of operations together with our financial statements and related notes appearing elsewhere in this quarterly report and the audited financial information and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2025, as filed with the Securities and Exchange Commission (“SEC”) on February 13, 2026 (“Annual Report ” ). FORWARD-LOOKING STATEMENTS This Quarterly Report on Form 10-Q, contains forward-looking statements regarding the expectations of Karyopharm Therapeutics Inc., herein referred to as “Karyopharm,” the “Company,” “we,” or “our,” with respect to the possible achievement of discovery and development milestones, our future discovery and development efforts, including regulatory submissions and approvals, potential inclusion of selinexor in combination with ruxolitinib in relevant compendia, our commercialization efforts, our partnerships and collaborations with third parties, our future operating results and financial position, our ability to continue as a going concern, our business strategy, and other objectives for future operations. We often use words such as “anticipate,” “believe,” “estimate,” “expect,” “intend,” “may,” “plan,” “predict,” “project,” “target,” “potential,” “will,” “would,” “could,” “should,” “continue,” and other words and terms of similar meaning to help identify forward-looking statements, although not all forward-looking statements contain these identifying words. You also can identify these forward-looking statements by the fact that they do not relate strictly to historical or current facts. There are a number of important risks and uncertainties that could cause actual results or events to differ materially from those indicated by forward-looking statements. These risks and uncertainties include, but are not limited to, those described in Part II, Item 1A - Risk Factors of this Quarterly Report on Form 10-Q. As a result of these and other factors, we may not actually achieve the plans, intentions, expectations or results disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make. We do not assume any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law. References to XPOVIO ® (selinexor) also refer to NEXPOVIO ® (selinexor) when discussing its approval and commercialization in certain countries or territories outside of the U.S. OVERVIEW We are a commercial-stage pharmaceutical company pioneering novel cancer therapies and dedicated to the discovery, development and commercialization of first-in-class drugs directed against nuclear export for the treatment of cancer. Our scientific expertise is based upon an understanding of the regulation of intracellular communication between the nucleus and the cytoplasm. We have discovered and are developing and commercializing novel, small molecule XPO1 inhibitor compounds that inhibit the nuclear export protein exportin 1 (“XPO1”). These compounds represent a new class of drug candidates with a novel mechanism of action that have the potential to treat a variety of diseases with high unmet medical need. Our lead asset, XPOVIO ® (selinexor), was the first oral XPO1 inhibitor to receive marketing approval, receiving its initial U.S. approval from the U.S. Food and Drug Administration in July 2019, and is currently approved and marketed in the U.S. for the following indications: • In combination with bortezomib and dexamethasone for the treatment of adult patients with multiple myeloma who have received at least one prior therapy. Approval in this indication was based on the results from the BOSTON ( Bo rtezomib, S elinexor and Dexame t has on e) trial; and • In combination with dexamethasone for the treatment of adult patients with relapsed or refractory multiple myeloma 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. Approval in this indication was based on the results from the STORM ( S elinexor T reatment of R efractory M yeloma) trial. Our primary focus is on marketing XPOVIO in its currently approved indications in multiple myeloma as well as developing and seeking regulatory approval of selinexor in myelofibrosis. Subject to obtaining additional funding, we plan to explore opportunities to develop our leading next-generation XPO1 inhibitor, eltanexor, in additional myeloproliferative neoplasms. The commercialization of XPOVIO in the U.S. is currently supported by sales representatives, nurse liaisons, and a market access team, as well as KaryForward ® , an extensive patient and healthcare provider support program. Our commercial efforts are also supplemented by patient support initiatives coordinated by our dedicated network of participating specialty pharmacy providers. The commercialization of XPOVIO and NEXPOVIO ® (selinexor) (the brand name for selinexor in Europe and the United Kingdom) outside of the U.S. is managed by our partners in their respective territories. XPOVIO/NEXPOVIO has received regulatory 21 Table of Contents approvals in various indications in more than 50 territories and countries outside the U.S. and is commercially available in a growing number of countries as our partners continue to secure reimbursement approvals. RECENT DEVELOPMENTS Phase 3 XPORT-EC-042 Topline Results On July 30, 2026, we announced topline results from our Phase 3 randomized, double-blind trial evaluating selinexor as a maintenance-only therapy compared to placebo in adult patients with TP53 wild-type advanced or recurrent endometrial cancer in which patients were randomized 1:1 to receive either a 60 mg, once-weekly, administration of oral selinexor or placebo until disease progression (the “XPORT-EC-042 Trial”). The trial did not meet its primary endpoint of progression free survival (“PFS”). The trial included two patient populations, for which the primary endpoint of PFS was designed to be tested sequentially: (1) a modified intent to treat population (“mITT”) that included patients with either (a) TP53 wild-type tumors with proficient mismatch repair status or (b) TP53 wild-type tumors with deficient mismatch repair status, who are medically ineligible to receive checkpoint inhibitors; and (2) the trial’s original intent to treat population, which included all patients enrolled in the trial whose tumors are TP53 wild-type, regardless of MMR status. A trend favoring the selinexor arm was observed in the mITT population (n=236), with a median PFS of 12.75 months in the selinexor arm compared to 7.43 months in the placebo arm (hazard ratio=0.76 [95% CI: 0.51, 1.12]; one-sided p-value=0.0791). The safety and tolerability profile of selinexor was consistent with its established safety profile, with no new safety signals observed. We intend to complete a full evaluation of the data from the XPORT-EC-042 Trial and plan to present the data at a future medical meeting. The results of the XPORT-EC-042 Trial do not affect ongoing trials of selinexor in other potential indications. Myelofibrosis Regulatory Update On July 30, 2026, we announced that we plan to submit a supplemental New Drug Application (“sNDA”) to the U.S. Food and Drug Administration (“FDA”) in August 2026 seeking accelerated approval of selinexor in combination with ruxolitinib for the treatment of patients with myelofibrosis. The planned submission follows productive engagements with the FDA, including written feedback that spleen volume reduction ≥ 35% (“SVR35”) appears to qualify as a reasonably likely surrogate endpoint to predict overall survival and can be used to support an sNDA under the accelerated approval pathway. We plan to use overall survival data from long-term follow-up of our ongoing randomized, double-blind Phase 3 clinical trial to evaluate the efficacy and safety of once-weekly selinexor in combination with ruxolitinib versus placebo plus ruxolitinib in JAK2 inhibitor (“JAKi”)-naive myelofibrosis patients (the “SENTRY Trial”) to verify clinical benefit. Overall survival is a pre-specified secondary endpoint of the SENTRY Trial. The trial does not permit patient crossover; patients, investigators and the Karyopharm study team remain blinded to treatment assignment during ongoing follow-up. The results from our SENTRY Trial will be the basis of the planned sNDA, including the statistically significant improvement in SVR35 at week 24, the rapid, deep and sustained nature of the spleen responses, a promising overall survival signal, reductions in variant allele frequency and the overall safety data package. We remain on track for a planned August 2026 sNDA submission and have continued to productively engage with the FDA on the final details of the data that will be used to confirm the anticipated clinical benefit, a requirement under the accelerated approval pathway. These confirmatory data will be used to convert potential accelerated approval to traditional approval. We continue to address the FDA’s requests and provide the FDA with additional data and information in advance of the sNDA submission in August 2026. We intend to request Priority Review at the time of submission of the sNDA, which, if granted, would result in a Prescription Drug User Fee Act target action date of approximately six months following the FDA’s receipt of the application. Phase 3 SENTRY Trial Topline Results On March 24, 2026, we announced topline results from the SENTRY Trial in which patients were randomized 2:1 to 60 mg of selinexor once weekly plus ruxolitinib or placebo plus ruxolitinib. The ruxolitinib dose was determined based on the patients’ baseline platelet count per the drug’s prescribing information. The SENTRY Trial met the first co-primary endpoint, demonstrating statistically significant improvement in SVR35 for patients treated with the combination of selinexor plus ruxolitinib, with rapid, deep and sustained spleen volume reduction rates seen in the combination arm, but did not meet its second co-primary endpoint in absolute total symptom score. The mean change in absolute total symptom score at week 24 relative to baseline was comparable across the two arms with similar symptom improvement relative to baseline; the difference across the two arms was not statistically significant. In 22 Table of Contents addition, a promising overall survival signal was observed in the topline data, which further reinforces the relevance of XPO1 inhibition in combination with ruxolitinib in frontline myelofibrosis. Further, a greater proportion of patients on the combination arm compared to ruxolitinib alone experienced reductions in variant allele frequency, which may be indicative of an underlying effect on disease biology, raising the potential for disease modification. The combination demonstrated a manageable safety and tolerability profile consistent with the known profile of selinexor and ruxolitinib individually. No new safety signals were observed. Other Clinical Trial Updates We continue to enroll JAKi-naïve myelofibrosis patients in the Phase 2 clinical trial to evaluate the safety and efficacy of selinexor as a monotherapy in patients with JAKi-naïve myelofibrosis with moderate thrombocytopenia (the “SENTRY-2 Trial”). We completed enrollment of the 60 mg cohort of the SENTRY-2 trial and began enrolling patients into the 40 mg cohort. We expect to report topline data from all patients in the 60 mg cohort with at least 24 weeks of follow-up in the second half of 2026. Patients enrolled in a randomized global Phase 3 trial sponsored by the European Myeloma Network evaluating an all-oral combination of selinexor 40 mg in combination with pomalidomide and dexamethasone versus elotuzumab, pomalidomide, and dexamethasone in patients with previously treated multiple myeloma who received an anti-CD38 in their immediate prior line of therapy (the “EMN29 Trial”) continued to be followed for PFS events contributing towards the primary endpoint. We expect to report topline data from this event-driven trial in the second half of 2026. In March 2026, we met with the FDA regarding the Accelerated Approval of the Diffuse Large B-Cell Lymphoma (“DLBCL”) indication of XPOVIO, which was granted on June 22, 2020 for the treatment of adult patients with relapsed or refractory DLBCL, not otherwise specified, including DLBCL arising from follicular lymphoma, after at least two lines of systemic therapy. The FDA requested and we agreed to voluntarily withdraw the accelerated approval of the DLBCL indication in light of the infeasibility of completing the confirmatory trial, especially considering the evolving treatment landscape, including the availability of new therapeutic options. As a result, we are in the process of terminating our ongoing company-sponsored trials in this indication. This withdrawal is not due to safety concerns with the DLBCL indication and does not affect the regulatory approval of any other indications for XPOVIO. Business and Financial Updates We expect our existing liquidity, including cash, cash equivalents and investments, as well as cash flow from net product revenue and license and other revenue, will enable us to fund our current operating plans into September 2026. With the assistance of our advisors, including our financial advisor Centerview Partners and other advisors, we are actively evaluating a range of financing opportunities and strategic alternatives with the objective of extending our cash runway, preserving strategic flexibility and maximizing long-term shareholder value as we advance our myelofibrosis program. On September 10, 2026, a $15.8 million principal payment is due under our senior secured term loan facility; if this payment is made without additional financing or a waiver from our lenders, we expect that (i) our cash, cash equivalents and investments will fall below our $10.0 million minimum liquidity covenant, which would trigger a default on our term loan and (ii) we will not have sufficient resources to fund our operations following such payment. In addition to the $15.8 million principal payment due on September 10, 2026, we have approximately $10.1 million of aggregate interest payments due on September 30, 2026 under our senior secured term loan, 2028 Notes and 2029 Notes, all as defined below. Our ability to successfully consummate a financing transaction or execute on a strategic alternative is dependent on a number of factors. There is no assurance that these efforts will result in additional funding, executing a strategic alternative transaction, will increase value for stakeholders, or will sufficiently address our ability to continue as a going concern. On February 27, 2026, we entered into the Second Amendment to Credit and Guaranty Agreement (the “Amendment”) with the lenders party thereto and Wilmington Savings Fund Society, FSB, as administrative agent and collateral agent, which amended our Credit and Guaranty Agreement, dated May 8, 2024 (as previously amended, the “Credit Agreement”). On February 27, 2026, we also entered into a Forbearance Agreement (the “Forbearance Agreement”) with (i) all the lenders under the Credit Agreement, (ii) all the holders of our 9.00% Convertible Senior Notes due 2029 (the “New 2029 Notes”) and 9.00% Convertible Senior Notes due 2028 (the “2028 Notes”), and (iii) the investor representative for the investors under our revenue interest financing agreement (collectively, the “Consenting Parties”). The effectiveness of the Forbearance Agreement was conditioned upon, among other things, the consummation of a sale and issuance of our common stock, in one or more transactions, resulting in proceeds to us of not less than $25.0 million actually received in cash before June 10, 2026 (the “Capital Raise Trigger”). The Capital Raise Trigger was satisfied and the Forbearance Agreement became effective in March 2026 upon receipt of the proceeds from the Private Placement (as defined below). Under the Amendment and the Forbearance Agreement, certain principal and interest payments were deferred until September 2026 and the Consenting Parties agreed not to exercise certain rights and remedies with respect to specified matters, including: (i) payment-related defaults through September 30, 2026 that would result from our non-payment of the interest due on June 30, 2026 for the New 2029 Notes and 23 Table of Contents 2028 Notes and (ii) any defaults that result from a requirement under the indentures of the New 2029 Notes and 2028 Notes for us to have a Minimum Liquidity Covenant Amount greater than the lesser of (i) $10.0 million plus 50% of the net cash proceeds received from certain debt and equity issuances and (ii) $25.0 million through October 10, 2026. After October 10, 2026, the minimum liquidity covenant will require minimum consolidated liquidity of $25.0 million. See “ Liquidity, Capital Resources and Going Concern ” below for a further discussion of our liquidity and our need to raise additional capital. On March 24, 2026, we entered into a Securities Purchase Agreement with RA Capital Healthcare Fund, L.P. (“RA Capital Management”) pursuant to which we issued and sold in a private placement (the “Private Placement”): (i) 1,030,354 shares of common stock, (ii) pre-funded warrants to purchase up to 3,391,164 shares of common stock, and (iii) accompanying warrants to purchase 4,421,518 shares of common stock with an exercise price of $10.00 per share (the “2026 Warrants”) for aggregate net proceeds of $26.9 million. The 2026 Warrants are exercisable until August 29, 2026 and the pre-funded warrants do not expire. As of June 30, 2026, none of these warrants have been exercised. In addition, in March 2026, we issued and sold an aggregate of 2,994,441 shares of Common Stock under our Open Market Sale Agreement SM , by and between us and Jefferies LLC, dated February 17, 2023 for total proceeds, net of sales commissions, of approximately $19.8 million. As of June 30, 2026, we had an accumulated deficit of $1.8 billion. We had operating losses of $49.3 million and $57.6 million for the six months ended June 30, 2026 and 2025, respectively. We recognized total revenue of $68.5 million and $67.9 million for the six months ended June 30, 2026 and 2025, respectively, including $59.9 million and $50.7 million of XPOVIO net product revenue, respectively, and $8.6 million and $17.2 million of license revenue, respectively. As of June 30, 2026, we had $65.1 million in cash, cash equivalents, and investments. Based on our current business plan and current capital resources, combined with the uncertainty regarding the availability of additional funding or other strategic alternatives and considering our debt service obligations and financial covenant to maintain minimum liquidity, we have concluded that there is substantial doubt regarding our ability to continue as a going concern within one year after the date the accompanying condensed consolidated financial statements are issued. See “ Liquidity, Capital Resources, and Going Concern ” below for a further discussion of our liquidity and the conditions that raise substantial doubt regarding our ability to continue as a going concern. CRITICAL ACCOUNTING ESTIMATES We believe that several accounting policies are important to understanding our historical and future performance. We refer to these policies as “critical” because these specific areas generally require us to make judgments and estimates about matters that are uncertain at the time we make the estimate, and different estimates - which also would have been reasonable - could have been used, which would have resulted in different financial results. There have been no changes to the critical accounting estimates we identified in Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations in our Annual Report. 24 Table of Contents RESULTS OF OPERATIONS The following table summarizes our results of operations (in thousands, except for percentages): For the Three Months Ended June 30, For the Six Months Ended June 30, 2026 2025 $ Change % Change 2026 2025 $ Change % Change Product revenue, net $ 30,776 $ 29,681 $ 1,095 4 % $ 59,939 $ 50,735 $ 9,204 18 % License and other revenue 2,656 8,248 (5,592 ) (68 )% 8,559 17,209 (8,650 ) (50 )% Total revenue 33,432 37,929 (4,497 ) (12 )% 68,498 67,944 554 1 % Operating expenses: Cost of sales 1,085 1,051 34 3 % 2,430 2,352 78 3 % Research and development 28,957 32,788 (3,831 ) (12 )% 62,754 67,406 (4,652 ) (7 )% Selling, general and administrative 25,916 28,477 (2,561 ) (9 )% 52,600 55,829 (3,229 ) (6 )% Loss from operations (22,526 ) (24,387 ) 1,861 (8 )% (49,286 ) (57,643 ) 8,357 (14 )% Other expense, net (44,497 ) (12,825 ) (31,672 ) >100% (40,128 ) (2,995 ) (37,133 ) >100% Loss before income taxes (67,023 ) (37,212 ) (29,811 ) 80 % (89,414 ) (60,638 ) (28,776 ) 47 % Income tax provision — (40 ) 40 (100 )% (1 ) (76 ) 75 (99 )% Net loss $ (67,023 ) $ (37,252 ) $ (29,771 ) 80 % $ (89,415 ) $ (60,714 ) $ (28,701 ) 47 % Product Revenue, net (in thousands, except for percentages) For the Three Months Ended June 30, For the Six Months Ended June 30, 2026 2025 $ Change % Change 2026 2025 $ Change % Change Product revenue, net $ 30,776 $ 29,681 $ 1,095 4 % $ 59,939 $ 50,735 $ 9,204 18 % To date, our only source of product revenue has been from the U.S. sales of XPOVIO. Net product revenue for the three months ended June 30, 2026 remained relatively consistent as compared to the three months ended June 30, 2025, reflecting relatively consistent demand for XPOVIO in an increasingly competitive multiple myeloma marketplace. Net product revenue for the six months ended June 30, 2026 increased by $9.2 million compared to the six months ended June 30, 2025. This increase was primarily attributable to an unusually high product returns reserve recorded during the six months ended June 30, 2025, which reduced net revenue in the prior-year period. The increase was also driven by lower gross-to-net deductions, primarily due to lower chargebacks and a reduction in the Medicare rebate reserve during the six months ended June 30, 2026 compared to the prior-year period. License and Other Revenue (in thousands, except for percentages) For the Three Months Ended June 30, For the Six Months Ended June 30, 2026 2025 $ Change % Change 2026 2025 $ Change % Change Menarini Group (“Menarini”) $ 1,899 $ 7,621 $ (5,722 ) (75 )% $ 3,727 $ 15,817 $ (12,090 ) (76 )% Antengene Therapeutics Limited (“Antengene”) 680 489 191 39 % 1,179 1,141 38 3 % Other 77 138 (61 ) (44 )% 3,653 251 3,402 >100% Total license and other revenue $ 2,656 $ 8,248 $ (5,592 ) (68 )% $ 8,559 $ 17,209 $ (8,650 ) (50 )% License and other revenue for the three months ended June 30, 2026 decreased by $5.6 million compared to the three months ended June 30, 2025, primarily due to a $6.5 million decrease in reimbursement revenue from Menarini for development-related expenses following the expiration of its reimbursement obligation on December 31, 2025. This decrease was partially offset by a $0.9 million increase in royalty revenue from our partners. License and other revenue for the six months ended June 30, 2026 decreased by $8.7 million as compared to the six months 25 Table of Contents ended June 30, 2025, primarily due to a decrease of $13.5 million of reimbursement revenue from Menarini for development-related expenses following the expiration of its reimbursement obligation on December 31, 2025. This decrease was partially offset by higher milestone and royalty revenue, including a $3.5 million milestone payment under a licensing agreement with a privately held biotechnology company related to the research, development and commercialization of verdinexor for the treatment of cancer in certain animals, as well as a $1.2 million increase in royalty revenue from our partners. Operating Expenses (in thousands, except for percentages) For the Three Months Ended June 30, For the Six Months Ended June 30, 2026 2025 $ Change % Change 2026 2025 $ Change % Change Cost of sales $ 1,085 $ 1,051 $ 34 3 % $ 2,430 $ 2,352 $ 78 3 % Research and development 28,957 32,788 (3,831 ) (12 )% 62,754 67,406 (4,652 ) (7 )% Selling, general and administrative 25,916 28,477 (2,561 ) (9 )% 52,600 55,829 (3,229 ) (6 )% Total operating expenses $ 55,958 $ 62,316 $ (6,358 ) (10 )% $ 117,784 $ 125,587 $ (7,803 ) (6 )% Cost of Sales Cost of sales for the three and six months ended June 30, 2026 and 2025 were relatively consistent. Research and Development Expenses (in thousands, except for percentages) For the Three Months Ended June 30, For the Six Months Ended June 30, 2026 2025 $ Change % Change 2026 2025 $ Change % Change Clinical trial and related costs: Selinexor in myelofibrosis $ 7,146 $ 8,169 $ (1,023 ) (13 )% $ 18,063 $ 19,586 $ (1,523 ) (8 )% Selinexor in endometrial cancer 4,174 4,105 69 2 % 8,764 8,331 433 5 % Selinexor in multiple myeloma 1,393 3,240 (1,847 ) (57 )% 3,202 5,165 (1,963 ) (38 )% Other programs 413 478 (65 ) (14 )% 755 1,056 (301 ) (29 )% Non-program specific clinical trial and related costs 501 1,718 (1,217 ) (71 )% 1,528 2,941 (1,413 ) (48 )% Total clinical trial and related costs 13,627 17,710 (4,083 ) (23 )% 32,312 37,079 (4,767 ) (13 )% Unallocated costs: Personnel 10,454 9,615 839 9 % 21,178 20,125 1,053 5 % Consulting, professional and other 4,357 4,281 76 2 % 7,859 8,105 (246 ) (3 )% Stock-based compensation 519 1,182 (663 ) (56 )% 1,405 2,097 (692 ) (33 )% Total unallocated costs 15,330 15,078 252 2 % 30,442 30,327 115 0 % Total research and development expenses $ 28,957 $ 32,788 $ (3,831 ) (12 )% $ 62,754 $ 67,406 $ (4,652 ) (7 )% At any one time, we have a number of ongoing clinical development programs that we are conducting independently or in collaboration with third parties. We track our external clinical trial and related costs on a program-by-program basis. Our major programs reported in the table above include our clinical programs in myelofibrosis, endometrial cancer and multiple myeloma. To the extent that external clinical trial and related costs are not attributable to a major program, they are included in “ Other programs ” and to the extent external clinical trial and related costs cannot be allocated to a specific program, they are included in “ Non-program specific clinical trial and related costs .” We also have unallocated research and development costs, which we do not track on a program-by-program basis. These costs represent expenses incurred across multiple programs or to support our general research and development operations. Research and development expenses for the three and six months ended June 30, 2026 decreased by $3.8 million and $4.7 million, respectively, as compared to the three and six months ended June 30, 2025. The decreases were driven by our continued 26 Table of Contents prioritization, focus, and efficient spending while advancing our late-stage programs, with our Phase 3 trials having completed enrollment. Research and development expenses for our multiple myeloma program decreased by $1.8 million and $2.0 million for the three and six month periods, respectively, mainly driven by timing of comparator drug expenses related to the EMN29 trial. The decrease in our myelofibrosis program expenses was primarily driven by the SENTRY Trial transitioning from enrollment to the maintenance phase, resulting in lower trial site and patient-related costs of $1.1 million and $1.5 million for the three and six month periods, respectively. We expect research and development expenses to remain relatively consistent as we continue to balance the near-term requirements of our ongoing programs with actions intended to materially reduce our cost base and advance our most important near-term value drivers in myelofibrosis. Selling, General and Administrative Expenses (in thousands, except for percentages) For the Three Months Ended June 30, For the Six Months Ended June 30, 2026 2025 $ Change % Change 2026 2025 $ Change % Change Personnel costs $ 12,735 $ 13,809 $ (1,074 ) (8 )% $ 26,903 $ 28,466 $ (1,563 ) (5 )% Consulting, professional and other costs 11,794 12,102 (308 ) (3 )% 22,215 22,198 17 0 % Stock-based compensation 1,387 2,566 (1,179 ) (46 )% 3,482 5,165 (1,683 ) (33 )% Total selling, general and administrative expenses $ 25,916 $ 28,477 $ (2,561 ) (9 )% $ 52,600 $ 55,829 $ (3,229 ) (6 )% Selling, general and administrative expenses for the three and six months ended June 30, 2026 decreased by $2.6 million and $3.2 million, respectively, as compared to the three and six months ended June 30, 2025. The decreases were primarily driven by proactive cost containment while maintaining disciplined alignment of pre-launch investments with clinical and regulatory milestones. In the near term, we expect selling, general and administrative expenses to increase due to incremental professional advisory fees related to our ongoing liquidity and strategic initiatives, as well as targeted retention costs intended to support organizational continuity and execution during this pivotal period. Other Income (Expense), net (in thousands, except for percentages) For the Three Months Ended June 30, For the Six Months Ended June 30, 2026 2025 $ Change % Change 2026 2025 $ Change % Change Interest expense $ (13,144 ) $ (11,228 ) $ (1,916 ) 17 % $ (25,697 ) $ (22,222 ) $ (3,475 ) 16 % Interest income 722 613 109 18 % 1,233 1,613 (380 ) (24 )% Other (expense) income, net (32,075 ) (2,210 ) (29,865 ) >100% (15,664 ) 17,614 (33,278 ) (>100)% Total other expense, net $ (44,497 ) $ (12,825 ) $ (31,672 ) >100% $ (40,128 ) $ (2,995 ) $ (37,133 ) >100% Total other expense, net for the three and six months ended June 30, 2026 increased by $31.7 million and $37.1 million, respectively, as compared to the three and six months ended June 30, 2025 . The increases were primarily due to the fair value remeasurement of embedded derivatives and liability-classified common stock warrants, both of which are non-cash items. There was also an increase in interest expense due to an increase to the interest rate in October 2025 on our senior secured term loan facility and convertible debt. Future period results may continue to be affected by non-cash gains or losses from the remeasurement of embedded derivatives and liability-classified common stock warrants, which will vary depending on movements in our stock price and other market factors. LIQUIDITY, CAPITAL RESOURCES AND GOING CONCERN We have historically financed our operations primarily through a combination of proceeds from (i) product revenue sales; (ii) public and private placements of equity securities; (iii) the issuance of convertible debt; (iv) a term loan; (v) our deferred royalty obligation; (vi) at the market offerings; and (vii) business development activities. As of June 30, 2026, our principal source of liquidity 27 Table of Contents was $65.1 million of cash, cash equivalents, and investments. We have had recurring losses since inception and incurred an operating loss of $49.3 million for the six months ended June 30, 2026. We anticipate that we will continue to incur significant operating losses in the foreseeable future. Based on our current business plan and current capital resources, combined with the uncertainty regarding the availability of additional funding or other strategic transactions and considering our debt service obligations and financial covenant to maintain minimum liquidity, we have concluded that there is substantial doubt regarding our ability to continue as a going concern within one year after the date the accompanying condensed consolidated financial statements are issued. We expect that our existing liquidity, including cash, cash equivalents, and investments as well as cash flow from net product revenue and license and other revenue, will enable us to fund our current operating plans into September 2026. With the assistance of our advisors, including our financial advisor Centerview Partners and other advisors, we are actively evaluating a range of financing opportunities and strategic alternatives with the objective of extending our cash runway, preserving strategic flexibility and maximizing long-term shareholder value as we advance our myelofibrosis program. On September 10, 2026, a $15.8 million principal payment is due under our senior secured term loan facility; if this payment is made without additional financing or a waiver from our lenders, we expect that (i) our cash, cash equivalents and investments will fall below our $10.0 million minimum liquidity covenant, which would trigger a default on our term loan and (ii) we will not have sufficient resources to fund our operations following such payment. In addition to the $15.8 million principal payment due on September 10, 2026, we have approximately $10.1 million of aggregate interest payments due on September 30, 2026 under our senior secured term loan, 2028 Notes and 2029 Notes. See “ Liquidity and Capital Resources – Funding Requirements ” below and Note 1 “ Nature of Business, Basis of Presentation and Segment Information ” to the condensed consolidated financial statements included under Part I, Item 1 of this Quarterly Report on Form 10-Q for a further discussion of our liquidity and the conditions that raise substantial doubt regarding our ability to continue as a going concern. Cash Flows The following table provides information regarding our cash flows (in thousands): For the Six Months Ended June 30, 2026 2025 $ Change % Change Net cash used in operating activities $ (47,659 ) $ (57,681 ) $ 10,022 (17 )% Net cash (used in) provided by investing activities (6,836 ) 33,573 (40,409 ) (>100)% Net cash provided by financing activities 48,904 356 48,548 >100% Effect of exchange rates on cash, cash equivalents and restricted cash (2 ) 13 (15 ) (>100)% Net decrease in cash, cash equivalents and restricted cash $ (5,593 ) $ (23,739 ) $ 18,146 (76 )% Operating activities. Net cash used in operating activities decreased by $10.0 million for the six months ended June 30, 2026 compared to the six months ended June 30, 2025, primarily due to a decrease in interest and royalty payments in 2026 as a result of certain debt modifications which occurred in October 2025. Investing activities. Net cash provided by investing activities decreased by $40.4 million for the six months ended June 30, 2026 compared to the six months ended June 30, 2025, primarily due to lower proceeds from maturities of investments as a result of a lower investment balance between periods as well as increased purchases of investments during the six months ended June 30, 2026 due to the cash inflows from the financing activities described below. Financing activities . Net cash provided by financing activities increased by $48.5 million for the six months ended June 30, 2026 compared to the six months ended June 30, 2025, primarily due to the proceeds from the issuance of common stock during the six months ended June 30, 2026 under our Private Placement and Open Market Sale Agreement, as described in further detail under the heading “ Sources of Liquidity ”. Sources of Liquidity On March 24, 2026, we entered into a Securities Purchase Agreement with RA Capital Management pursuant to which we issued and sold in a private placement: (i) 1,030,354 shares of common stock, (ii) pre-funded warrants to purchase up to 3,391,164 shares of common stock, and (iii) accompanying 2026 Warrants to purchase 4,421,518 shares of common stock with an exercise price of $10.00 per share for aggregate net proceeds of $26.9 million. The 2026 Warrants are exercisable until August 29, 2026 and the pre-funded warrants do not expire. As of June 30, 2026, none of these warrants have been exercised. 28 Table of Contents In October 2025, we entered into a securities purchase agreement with certain institutional investors to which we issued and sold, in a private placement, (i) 1,487,917 shares of common stock and (ii) accompanying warrants to purchase 1,317,771 shares of common stock at an exercise price of $6.64 per share. We received aggregate net proceeds of approximately $8.4 million. In October 2025, we entered into a note purchase agreement pursuant to which we issued and sold, in a private placement, $15.0 million aggregate principal amount of the 2028 Notes to certain holders of our existing 6.00% senior secured convertible notes due 2029. The 2028 Notes are senior secured second-lien obligations and bear interest at a rate of 9.00% per year payable quarterly in arrears on March 31, June 30, September 30, and December 31 of each year, beginning on December 31, 2025. Cash interest payments will begin on September 30, 2026. The 2028 Notes will mature on October 15, 2028, unless earlier converted, redeemed or repurchased in accordance with their terms. In September 2019, we and certain of our subsidiaries entered into the Revenue Interest Financing Agreement with certain entities managed by HCRx, which was subsequently amended on June 23, 2021, August 1, 2023, May 8, 2024, August 14, 2025, August 27, 2025 and October 7, 2025 and which was assigned in July 2025 by HCRx to an affiliate of KKR & Co. Inc. in connection with its acquisition of a majority ownership stake in HCRx (the “Revenue Interest Agreement” and, as amended, the “Amended Revenue Interest Agreement”), pursuant to which, HCRx paid us a total of $135.0 million, less certain transaction expenses. On October 7, 2025, we entered into the Sixth Amendment to the Revenue Interest Financing Agreement pursuant to which (i) HCRx waived our obligation to pay royalties on revenue recognized between April 1, 2025 and March 31, 2026 and (ii) we agreed to increase the Applicable Tiered Percentage (as defined in the Amended Revenue Interest Agreement ) to 8.00% beginning on April 1, 2026. The total amount payable under the Revenue Interest Financing Agreement will remain capped at $263.3 million. For additional information, see Note 10, “ Long-Term Obligations ”, to the condensed consolidated financial statements included under Part I, Item 1 of this Quarterly Report on Form 10-Q. In May 2024, we entered into a credit and guaranty agreement (the “Credit Agreement”) with certain existing lenders and HCRx, which provides for a senior secured term loan facility of $100.0 million (the “Term Loan”). On October 7, 2025, we entered into the First Amendment and Waiver to Credit and Guaranty Agreement, pursuant to which, among other things, the lenders provided $12.5 million principal amount of additional loans (the “Amended Term Loan”). On February 27, 2026, we entered into the Second Amendment to Credit and Guaranty Agreement (the “Amended Credit Agreement”). The amendments to the Credit Agreement include, among other things (i) reducing the financial covenant requiring us to maintain liquidity of at least the lesser of (i) $10.0 million plus 50% of the net cash proceeds received from certain debt and equity issuances and (ii) $25.0 million, through October 10, 2026, after which we will be required to maintain liquidity of at least $25.0 million and (ii) increasing the interest rate on borrowings under the Amended Term Loan to the secured overnight financing rate plus 10.25% for interest payments occurring after June 30, 2025. Interest on borrowings under the Amended Term Loan incurred from July 1, 2025 to June 30, 2026 were paid in kind and we are obligated to make cash interest payments beginning on September 30, 2026. For additional information, see Note 10, “ Long-Term Obligations ”, to the condensed consolidated financial statements included under Part I, Item 1 of this Quarterly Report on Form 10-Q. In February 2023, we entered into an Open Market Sale Agreement (the “Open Market Sale Agreement”) with Jefferies LLC, as agent (“Jefferies”). Under the Open Market Sale Agreement, we may issue and sell shares of our common stock having an aggregate offering price of up to $100.0 million (the “Shares”) from time to time through Jefferies. During the six months ended June 30, 2026, we sold an aggregate of 2,994,441 Shares under the Open Market Sale Agreement, resulting in net proceeds of $19.8 million. We did not sell any Shares under the Open Market Sale Agreement during the six months ended June 30, 2025. Pursuant to a prospectus we thereafter filed with the SEC as part of a registration statement on Form S-3 on May 4, 2026, as of June 30, 2026, $100.0 million of Shares were available for issuance and sale under the Open Market Sale Agreement. During the six months ended June 30, 2026, we received $3.5 million in milestone payments under our license and distribution agreements pursuant to which we are entitled to receive additional milestone payments, if certain development goals and sales milestones are achieved as well as royalties on future net sales of the licensed and sold products in the territories under such arrangements. Commitments, Contingencies and Contractual Obligations Operating Leases We are party to an operating lease of office and research space in Newton, Massachusetts, which was amended in November 2024 and under which we currently lease a total of 52,224 square feet of office space through September 30, 2030. Contractual Obligations 29 Table of Contents We have contractual obligations under our (i) Amended Credit Agreement; (ii) 2028 Notes; (iii) New 2029 Notes; and (iv) Amended Revenue Interest Agreement as disclosed in Note 10, “ Long-Term Obligations ”, to the condensed consolidated financial statements included under Part I, Item 1 of this Quarterly Report on Form 10-Q. See below under “ Funding Requirements ” for the amounts due under each of these contractual obligations. Funding Requirements We expect to continue to incur costs related to our clinical development programs as we continue to advance our clinical programs in myelofibrosis and multiple myeloma, as well as costs associated with continued patient follow-up and other wind-down activities related to our endometrial cancer clinical trial. We also expect to incur commercialization expenses related to sales, marketing, manufacturing and distribution of our approved products, to the extent that these functions are not the responsibility of our collaborators. Our ability to become and remain profitable depends on our ability to generate revenue. There can be no assurance as to the amount or timing of any such revenue, and we may not achieve profitability in the near-term, if at all, as described more fully in the risk factor entitled “ We have incurred significant losses since inception, expect to continue to incur significant losses, and may never achieve or maintain profitability ,” under the heading “ Risk Factors ” in this Quarterly Report on Form 10-Q. Accordingly, we will need to continue to rely on additional financing to achieve our business objectives. Adequate additional financing may not be available to us on acceptable terms, or at all. Based on our current business plan and current capital resources, combined with the uncertainty regarding the availability of additional funding or other strategic alternatives and considering our debt service obligations and financial covenant to maintain minimum liquidity, we have concluded that there is substantial doubt regarding our ability to continue as a going concern within one year after the date the accompanying condensed consolidated financial statements are issued. See Note 1 “ Nature of Business, Basis of Presentation and Segment Information ” to the condensed consolidated financial statements included under Part I, Item 1 of this Quarterly Report on Form 10-Q for a further discussion of the conditions that raise substantial doubt regarding our ability to continue as a going concern. We expect that our existing liquidity, including cash, cash equivalents, and investments as well as cash flow from net product revenue and license and other revenue, will enable us to fund our current operating plans into September 2026. With the assistance of our advisors, including our financial advisor Centerview Partners and other advisors, we are actively evaluating a range of financing opportunities and strategic alternatives with the objective of extending our cash runway, preserving strategic flexibility and maximizing long-term shareholder value as we advance our myelofibrosis program. On September 10, 2026, a $15.8 million principal payment is due under our senior secured term loan facility; if this payment is made without additional financing or a waiver from our lenders, we expect that (i) our cash, cash equivalents and investments will fall below our $10.0 million minimum liquidity covenant, which would trigger a default on our term loan and (ii) we will not have sufficient resources to fund our operations following such payment. In addition to the $15.8 million principal payment due on September 10, 2026, we have approximately $10.1 million of aggregate interest payments due on September 30, 2026 under our senior secured term loan, 2028 Notes and 2029 Notes. In addition, prior to October 10, 2026, the minimum liquidity covenant will increase by 50% of the net cash proceeds of any issuance of debt or sale of capital stock up to a maximum amount of $25.0 million and will increase to $25.0 million on October 10, 2026. We will require additional capital to fund our operations and clinical development of selinexor and to pursue regulatory approval of selinexor in myelofibrosis. Our ability to successfully consummate a financing transaction or execute on a strategic alternative is dependent on a number of factors. There is no assurance that these efforts will result in additional funding, executing a strategic alternative transaction, will increase value for stakeholders, or will sufficiently address our ability to continue as a going concern. Absent additional funding or our ability to successfully complete one or more strategic transactions to extend our cash runway beyond September 10, 2026, we will be unable to continue as a going concern and we may have to consider seeking protection under the bankruptcy laws, liquidating our assets or ceasing our operations. If we decide to seek protection under the bankruptcy laws, we expect that we would file for bankruptcy protection at a time that is earlier than when we would otherwise exhaust our cash resources. In any of these circumstances, it is likely that investors will lose all or part of their investment. If there remains substantial doubt about our ability to continue as a going concern, investors or other financing sources may be unwilling to provide funding to us on commercially reasonable terms, if at all. Further, our indebtedness, as discussed under the risk factor titled “ Our indebtedness could limit cash flow available for our operations, expose us to risks that could adversely affect our business, financial condition and results of operations and impair our ability to satisfy our obligations under the Amended Term Loan, the Convertible Notes, or the Amended Revenue Interest Agreement ,” may be unattractive to potential sources of funding and strategic partners and may decrease our ability to consummate a financing transaction or enter into a strategic alternative. Additionally, the negotiation and consummation of a financing transaction or strategic alternative may be costly and time-consuming. 30 Table of Contents Our future long-term capital requirements will depend on many factors, as described more fully in the risk factor entitled “ We need additional funding or to enter into strategic alternatives to achieve our business objectives. If we are unable to raise sufficient capital or to enter into strategic alternatives on acceptable terms to meet our needs, we may be forced to undertake additional cost reduction measures such as further reducing operating expenses, including through additional workforce reductions, delay, reduce or eliminate our research and development programs and/or commercialization efforts or at any time we may elect to or may be required to cease operations entirely, liquidate all or a portion of our assets, and/or seek protection under the U.S. Bankruptcy Code, and you may lose all or part of your investment,” un der the heading “Risk Factors ” in this Quarterly Report on Form 10-Q. In addition to the expenses required to fund our operations described above, our funding requirements as of June 30, 2026 also include the following: • Lease costs for our headquarters in Newton, Massachusetts of $8.5 million through September 30, 2030; • Future obligations related to the Amended Credit Agreement of $153.6 million through May 2028 in addition to the financial covenant to maintain minimum liquidity; • Future obligations related to the 2028 Notes of $19.2 million through October 15, 2028; • Future obligations related to the New 2029 Notes of $138.3 million through May 13, 2029; and • Future royalty obligations to HCRx under the Amended Revenue Interest Agreement of $116.2 million by October 1, 2035. 31 Table of Contents Item 3. Quantitative and Qualitati ve Disclosures About Market Risk. We are exposed to market risk related to changes in interest rates. We had cash, cash equivalents, and investments of $65.1 million as of June 30, 2026. Our primary exposure to market risk is interest rate sensitivity, which is affected by changes in the general level of U.S. interest rates. Due to the short-term duration of our investment portfolio and the low risk profile of our investments, an immediate 100 basis point shift in interest rates would not have a material effect on the fair market value of our cash equivalents. We do not believe our cash, cash equivalents, and investments have significant risk of default or illiquidity. While we believe our cash, cash equivalents, and investments do not contain excessive risk, we cannot provide absolute assurance that in the future our investments will not be subject to adverse changes in securities at one or more financial institutions that are in excess of federally insured limits. Given the potential instability of financial institutions, we cannot provide assurance that we will not experience losses on these deposits and investments. We are also exposed to market risk related to changes in foreign currency exchange rates. We contract with contract research organizations and contract manufacturing organizations that are located in Canada, the United Kingdom and Europe, which are denominated in foreign currencies. We also contract with a number of clinical trial sites outside of the U.S., and our budgets for those studies are frequently denominated in foreign currencies. We are subject to fluctuations in foreign currency rates in connection with these agreements. We do not currently hedge our foreign currency exchange rate risk.