What changed in this filing

/stocks — the workspaceLOADING

Item 2. Management’s Discussion and Analysis

2026-05-14 compared with 2025-11-03 · 139 added, 135 removed, 137 unchanged (67% of the section changed)

2 unchanged sentences

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 ” ).

Unless otherwise indicated, in this Quarterly Report on Form 10-Q, all share amounts and per share amounts have been adjusted to reflect a 1-for-15 reverse split of our common stock (the “Reverse Stock Split”).

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, 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.

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.

8 unchanged sentences

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 Selective Inhibitor of Nuclear Export (“SINE”) compounds that inhibit the nuclear export protein exportin 1 (“XPO1”).

These SINE 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.

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.

6 unchanged sentences

Approval in this indication was based on the results from the STORM ( S elinexor T reatment of R efractory M yeloma) trial.

• For the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma (“DLBCL”), not otherwise specified, including DLBCL arising from follicular lymphoma, after at least two lines of systemic therapy.

This indication was approved under accelerated approval based on response rate and was based on the results from the SADAL ( S elinexor A gainst D iffuse A ggressive L ymphoma) trial.

Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.

Our primary focus is on marketing XPOVIO in its currently approved indications as well as developing and seeking regulatory approval of selinexor as an oral agent targeting multiple high unmet need cancer indications, including our lead clinical programs in myelofibrosis and endometrial cancer and our other late-stage clinical program in multiple myeloma.

Depending on the data in our Phase 3 myelofibrosis and/or endometrial cancer programs and the availability of capital resources, we plan to explore opportunities to develop our leading next-generation XPO1 inhibitor, eltanexor, in additional myeloproliferative neoplasms and TP53 wild-type tumors.

The commercialization of XPOVIO in the U.S.

1 unchanged sentence

Our commercial efforts are also supplemented by patient support initiatives coordinated by our dedicated network of participating specialty pharmacy providers.

We plan to continue to educate physicians, other healthcare providers and patients about XPOVIO’s clinical profile and unique mechanism of action as we continue to expand XPOVIO use.

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 approval in various indications in 50 countries outside of the U.S.

XPOVIO/NEXPOVIO has received regulatory 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.

We completed enrollment in our ongoing Phase 3 SENTRY trial evaluating selinexor in combination with once or twice-daily ruxolitinib versus placebo plus ruxolitinib in JAKi-naive myelofibrosis patients in September 2025.

We expect to report top-line data from the SENTRY trial in March 2026.

We continue to enroll JAKi-naïve myelofibrosis patients with platelet counts above 50,000 in the selinexor 60 mg cohort of the Phase 2 SENTRY-2 trial.

A recently amended protocol includes patients with platelet counts above 100,000.

We expect to report top-line data from all patients in the 60 mg cohort with at least 24 weeks of follow-up in 2026.

We are continuing to enroll patients in the 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.

We expect to report top-line data from this event-driven trial in mid-2026.

Our primary focus is on marketing XPOVIO in its currently approved indications as well as developing and seeking the regulatory approval of selinexor as an oral agent targeting multiple high unmet need cancer indications, including our lead clinical programs in myelofibrosis and our other late-stage clinical programs in endometrial cancer and multiple myeloma.

We plan to continue to conduct clinical trials and to seek additional approvals for the use of selinexor as a single agent or in combination with other oncology therapies to expand the patient populations that are eligible for treatment with selinexor.

As announced in January 2024, further clinical development of our eltanexor program continues to remain on hold in an effort to focus our resources on our prioritized late-stage programs.

As of September 30, 2025, we had an accumulated deficit of $1.7 billion.

We had net losses of $93.8 million and $45.6 million for the nine months ended September 30, 2025 and 2024, respectively.

Based on our current business plan and current capital resources, given the uncertainty regarding the availability of additional funding or other strategic alternatives, and considering our debt service obligations and the 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 and Capital Resources ” below for a further discussion of our liquidity and the conditions that raise substantial doubt regarding our ability to continue as a going concern.

October 2025 Financing Transactions

On October 7, 2025, we entered into a series of transactions with our term loan lenders, holders of our outstanding convertible notes and other investors to provide financial flexibility, additional working capital and equitize maturing notes (collectively, the “Financing Transactions”).

The Financing Transactions included the following key components:

(i) $27.5 million in new term loan borrowings and new convertible debt;

(ii) $25.4 million of near-term deferrals of interest and royalty payments;

(iii) a temporary reduction of $15.0 million in our minimum liquidity covenant;

(iv) an exchange of $15.0 million aggregate principal amount of our convertible notes due 2029 for shares of common stock;

(v) an exchange of $24.3 million aggregate principal amount of our convertible notes due October 15, 2025 for shares of our common stock and warrants to purchase shares of our common stock;

and (vi) a private placement of shares of our common stock and warrants to purchase shares of our common stock for gross proceeds of approximately $8.8 million.

Following consummation of the Financing Transactions, we had $112.5 million outstanding under our senior secured term loan with a maturity date in May 2028 (the “Amended Term Loan”), $15.0 million aggregate principal amount of 9.00% senior secured convertible notes due October 2028, $103.5 million aggregate principal amount of 9.00% senior secured convertible notes due May 2029, and $116.2 million of maximum remaining payments payable under our revenue interest financing agreement.

Following consummation of the Financing Transactions, holders of pre-funded warrants to purchase common stock exercised pre-funded warrants to purchase an aggregate of 1,123,895 shares of common stock in cashless exercises, pursuant to which we issued an aggregate of 1,123,874 shares of common stock.

Please refer to Note 12 “ Subsequent Event ”, to the condensed consolidated financial statements contained within Part I, Item 1 of this Quarterly Report on Form 10-Q for additional details of the Financing Transactions.

RECENT DEVELOPMENTS

Phase 3 SENTRY Trial Topline Data Results

On March 24, 2026, we announced topline data results from our 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”) 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 spleen volume reduction of 35% or more 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 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.

Our key near term objectives in advancing our SENTRY program include:

engagement with the U.S.

Food and Drug Administration (“FDA”) to discuss the data from the SENTRY Trial and our supplemental new drug application filing plan;

disclosure of additional data from the Phase 3 SENTRY Trial at an upcoming medical meeting;

and potential inclusion of the combination in relevant compendia, which could occur in the second half of 2026.

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.

We have completed enrollment of our global, Phase 3, randomized, double-blind trial evaluating selinexor as a maintenance-only therapy following systemic therapy in patients with TP53 wild-type advanced or recurrent endometrial cancer (the “XPORT-EC-042 Trial”).

Approximately 220 patients enrolled in the modified intent-to-treat (“mITT”) population and 257 enrolled in the intent-to-treat population.

Enrollment in the mITT population was focused on patients with either proficient mismatch repair status tumors or patients with deficient mismatch repair status tumors who are medically ineligible for checkpoint inhibitors.

We expect to report topline data from this event-driven trial in mid-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”).

The patients enrolled in this event-driven trial continued to be followed for progression-free survival events contributing towards the primary endpoint.

We expect to report topline data from the EMN29 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 expect to terminate 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

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, we can defer certain principal and interest payments 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 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.

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 30 days following our public announcement of topline data results from our Phase 3 XPORT-EC-042 clinical trial of selinexor in patients with endometrial cancer and the pre-funded warrants do not expire.

As of March 31, 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 March 31, 2026, we had an accumulated deficit of $1.8 billion.

We had operating losses of $26.8 million and $33.3 million for the three months ended March 31, 2026 and 2025, respectively.

We recognized total revenue of $35.1 million and $30.0 million for the three months ended March 31, 2026 and 2025, respectively, including $29.2 million and $21.1 million of XPOVIO net product revenue, respectively, and $5.9 million and $9.0 million of license revenue, respectively.

As of March 31, 2026, we had $90.9 million in cash and cash equivalents.

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 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

5 unchanged sentences

The following table summarizes our results of operations (in thousands, except for percentages):

For the Three Months Ended September 30,

For the Nine Months Ended September 30,

For the Three Months Ended March 31,

Product revenue, net

6 unchanged sentences

Loss from operations

Other (expense) income, net

Other income, net

Loss before income taxes

1 unchanged sentence

Product Revenue, net (in thousands, except for percentages)

For the Three Months Ended September 30,

For the Nine Months Ended September 30,

For the Three Months Ended March 31,

Product revenue, net

1 unchanged sentence

sales of XPOVIO.

Net product revenue for the three months ended September 30, 2025 increased by $2.5 million as compared to the three months ended September 30, 2024.

The increase was primarily driven by gross-to-net favorability, reflecting lower 340B discounts, partially offset by higher Medicare discount program charges and increased deductions associated with group purchasing organization arrangements.

Net product revenue for the nine months ended September 30, 2025 decreased by $0.8 million as compared to the nine months ended September 30, 2024, due to an increase in the gross-to-net provision largely due to the increase in the product return reserve and Medicare rebates, partially offset by gross-to-net favorability driven by lower 340B discounts in the nine months ended September 30, 2025.

The product return reserve increased as a result of atypical returns in the first quarter of 2025, primarily driven by expired units returned from clinics and hospitals that had purchased these units following the 2020 approval of XPOVIO ®.

We expect net product revenue in the fourth quarter of 2025 to be consistent with the third quarter of 2025 due to both consistent gross-to-net adjustments and demand.

Net product revenue for the three months ended March 31, 2026 increased by $8.1 million compared to the same period in 2025.

This increase was primarily attributable to an unusually high product return reserve recorded in the prior-year period, which reduced net revenue in that period, as well as lower gross-to-net discounts, specifically a decrease in chargebacks and Medicare rebate reserve in the first quarter of 2026 compared to the first quarter of 2025.

License and Other Revenue (in thousands, except for percentages)

For the Three Months Ended September 30,

For the Nine Months Ended September 30,

For the Three Months Ended March 31,

Menarini Group (“Menarini”)

1 unchanged sentence

Total license and other revenue

License and other revenue for the three months ended September 30, 2025 increased by $2.7 million as compared to the three months ended September 30, 2024, primarily due to increased milestone-related revenue.

License and other revenue for the nine months ended September 30, 2025 decreased by $1.9 million as compared to the nine months ended September 30, 2024, primarily due to decreased milestone-related revenue.

We expect license and other revenue to decrease in the fourth quarter of 2025 as compared to the third quarter of 2025, reflecting lower expected milestone revenue and the fact that the maximum reimbursement revenue from Menarini was fully recognized in the third quarter.

License and other revenue for the three months ended March 31, 2026 decreased by $3.1 million as compared to the three months ended March 31, 2025, primarily due to a decrease of $7.0 million of reimbursement revenue from Menarini for development-related expenses as their obligation to reimburse us expired on December 31, 2025.

This decrease was partially offset by an increase in milestone-related revenue from our other partners in the three months ended March 31, 2026, primarily due to a $3.5 million milestone payment under a licensing agreement with a privately-held biotech company related to the research, development and commercialization of verdinexor for the treatment of cancer in certain animals.

We expect license and other revenue to decrease in the second quarter of 2026 as compared to the first quarter of 2026, as we do not anticipate recognizing any milestone-related revenue.

Operating Expenses (in thousands, except for percentages)

For the Three Months Ended September 30,

For the Nine Months Ended September 30,

For the Three Months Ended March 31,

Cost of sales

3 unchanged sentences

Cost of Sales

Cost of sales for the three months ended September 30, 2025 increased by $0.8 million as compared to the three months ended September 30, 2024, primarily due to an increase in charges to write-off inventory in excess of demand.

Cost of sales for the nine months ended September 30, 2025 and 2024 were relatively consistent.

We expect cost of sales to remain relatively consistent in the fourth quarter of 2025 as compared to the third quarter of 2025.

Cost of sales for the three months ended March 31, 2026 and 2025 were relatively consistent.

Research and Development Expenses (in thousands, except for percentages)

For the Three Months Ended September 30,

For the Nine Months Ended September 30,

For the Three Months Ended March 31,

Clinical trial and related costs:

12 unchanged sentences

We track our external clinical trial and related costs on a program-by-program basis.

Our major programs include our lead clinical programs in myelofibrosis and our other late-stage clinical programs in 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.

Our major programs include our lead clinical programs in myelofibrosis and endometrial cancer and our other late-stage clinical program in multiple myeloma.

These costs represent expenses incurred across multiple programs or to support our general research and development operations.

Research and development expenses for the three months ended September 30, 2025 decreased by $5.6 million as compared to the three months ended September 30, 2024.

The decrease was primarily driven by a $4.9 million reduction in clinical trial and related costs for selinexor in multiple myeloma, reflecting the reduced scope of our Phase 3 multiple myeloma trial, and a $2.6 million reduction in personnel and stock-based compensation costs resulting from lower headcount and contractor utilization following previously implemented cost reduction initiatives.

The decreases were partially offset by a $2.2 million increase in clinical trial and related costs for selinexor in myelofibrosis, which was driven by $2.6 million in costs associated with the purchase of comparator drug for use in the trial, partially offset by lower costs related to enrollment activities.

Research and development expenses for the nine months ended September 30, 2025 decreased by $12.0 million as compared to the nine months ended September 30, 2024.

The decrease was primarily attributable to an $8.7 million reduction in clinical trial and related costs for selinexor in multiple myeloma, reflecting the reduced scope of our Phase 3 trial, and a $6.6 million reduction in personnel and stock-based compensation costs resulting from lower headcount and contractor utilization following the previously implemented cost reduction initiatives.

These decreases were partially offset by a $6.4 million increase in clinical trial and related costs for selinexor in myelofibrosis, primarily due to increased trial activity and higher patient enrollment, as well as an increase of $2.3 million in costs associated with the purchase of comparator drug for use in the trial.

We expect research and development expenses to remain relatively consistent in the fourth quarter of 2025 compared to the third quarter of 2025, as we continue to invest in our ongoing Phase 3 clinical trials in myelofibrosis and endometrial cancer.

Research and development expenses for the three months ended March 31, 2026 were relatively consistent as compared to the three months ended March 31, 2025.

If the topline data of our trials is positive or we are able to submit a supplemental New Drug Application (“sNDA”), we expect our research and development expenses will increase, primarily due to costs associated with regulatory filings.

Selling, General and Administrative Expenses (in thousands, except for percentages)

For the Three Months Ended September 30,

For the Nine Months Ended September 30,

For the Three Months Ended March 31,

Personnel costs

2 unchanged sentences

Total selling, general and administrative expenses

Selling, general and administrative expenses for the three and nine months ended September 30, 2025 decreased by $1.0 million and $5.8 million, respectively, compared to the corresponding periods in 2024.

The decreases were primarily due to lower headcount and contractor utilization resulting from previously implemented cost reduction initiatives that were largely offset by an increase in professional fees incurred in connection with the Financing Transactions and other strategic initiatives of $2.7 million and $4.3 million, for the three and nine months ended September 30, 2025, respectively.

We expect our selling, general and administrative expenses to remain relatively consistent in the fourth quarter of 2025 as compared to the third quarter of 2025, reflecting the continued impact of our cost reduction initiatives, partially offset by fees incurred in connection with the Financing Transactions.

Selling, general and administrative expenses for the three months ended March 31, 2026 were relatively consistent as compared to the three months ended March 31, 2025.

If the anticipated topline data of our trials in 2026 is positive or we are able to submit a sNDA, we expect that our selling, general administrative expenses will increase, primarily due to launch preparation costs.

Other Income (Expense), net (in thousands, except for percentages)

For the Three Months Ended September 30,

For the Nine Months Ended September 30,

For the Three Months Ended March 31,

Interest expense

Interest income

Gain on extinguishment of debt

Other (expense) income

Total other (expense) income, net

Total other (expense) income, net for the three and nine months ended September 30, 2025 increased as compared to the three and nine months ended September 30, 2024 by $12.1 million and $63.6 million, respectively, compared to the corresponding periods in 2024.

The increases were primarily due to the remeasurement of embedded derivatives and liability-classified common stock warrants, both of which are non-cash items.

In addition, the nine months ended September 30, 2024 included a $44.7 million non-cash gain on extinguishment of debt.

The increases were further impacted by higher interest expense associated with the senior secured term loan facility and 2029 Notes, both issued in May 2024, and decreased interest income resulting from reduced investment balances during the 2025 periods compared to 2024.

We expect total other (expense) income, net to remain relatively consistent in the fourth quarter of 2025 compared to the third quarter of 2025, excluding the impact of the Financing Transactions.

However, 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 AND CAPITAL RESOURCES

Other income, net

Total other income, net

Total other income, net for the three months ended March 31, 2026 decreased as compared to the three months ended March 31, 2025 by $5.5 million.

The decrease was 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;

5 unchanged sentences

and (vii) business development activities.

As of September 30, 2025, our principal source of liquidity was $45.9 million of cash, cash equivalents and investments.

Our cash balance as of September 30, 2025 reflects the benefit of $7.4 million of interest and royalties that were paid in kind in connection with the Financing Transactions announced on October 8, 2025.

We have had recurring losses since inception and incurred a loss of $93.8 million for the nine months ended September 30, 2025.

As of March 31, 2026, our principal source of liquidity was $90.9 million of cash and cash equivalents.

We have had recurring losses since inception and incurred an operating loss of $26.8 million for the three months ended March 31, 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, given the uncertainty regarding the availability of additional funding or other strategic alternatives and considering our debt service obligations and the 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 currently expect that our existing cash, cash equivalents and investments as well as cash flows from net product revenue and license and other revenue, will enable us to fund our current operating plans into the second quarter of 2026.

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 I 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.

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 and cash equivalents as of March 31, 2026 as well as cash flow from net product revenue and license and other revenue, will enable us to fund our current operating plans to late in the third quarter of 2026.

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.

The following table provides information regarding our cash flows (in thousands):

For the Nine Months Ended September 30,

For the Three Months Ended March 31,

Net cash used in operating activities

2 unchanged sentences

Effect of exchange rates on cash, cash equivalents and restricted cash

Net (decrease) increase in cash, cash equivalents and restricted cash

Net increase (decrease) in cash, cash equivalents and restricted cash

Operating activities.

The $38.1 million decrease in net cash used in operating activities for the nine months ended September 30, 2025 compared to the nine months ended September 30, 2024 was primarily driven by changes in working capital resulting primarily from decreased spend year-over-year as a result of the realization of previously implemented cost reduction initiatives.

Net cash used in operating activities decreased by $16.3 million for the three months ended March 31, 2026 compared to the three months ended March 31, 2025, primarily due to a $7.3 million decrease in interest and royalty payments as a result of certain debt modifications which occurred in October 2025.

Investing activities.

The $42.3 million decrease in net cash provided by investing activities for the nine months ended September 30, 2025 compared to the nine months ended September 30, 2024 was driven by a $99.8 million decrease in proceeds from the maturities of investments, partially offset by a $57.3 million decrease in purchases of investments.

Net cash provided by investing activities decreased by $12.1 million for the three months ended March 31, 2026 compared to the three months ended March 31, 2025, primarily due to lower proceeds from maturities of investments as a result of a lower investment balance in the three months ended March 31, 2026.

Financing activities .

The $40.6 million decrease in net cash provided by financing activities for the nine months ended September 30, 2025 compared to the nine months ended September 30, 2024 was driven primarily by activity during the nine months

ended September 30, 2024 and consisted of $83.3 million of proceeds from the term loan, partially offset by a $40.5 million payment of our deferred royalty obligation and a $2.6 million payment of debt issuance costs.

Net cash provided by financing activities increased by $49.8 million for the three months ended March 31, 2026 compared to the three months ended March 31, 2025, primarily due to the proceeds from the issuance of common stock during the three months ended March 31, 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 October 7, 2025, we entered into a securities purchase agreement with certain institutional investors to which we issued and sold, in a private placement, an aggregate of (i) 1,487,917 shares of common stock at a price per share of $5.88 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 gross proceeds of approximately $8.8 million.

On October 7, 2025, we entered into a note purchase agreement pursuant to which issued and sold, in a private placement, $15.0 million aggregate principal amount of new 9.00% senior secured convertible notes due 2028 (the “2028 Notes”) to certain holders of our existing 6.00% senior secured convertible notes due 2029.

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.

As of March 31, 2026, none of these warrants have been exercised.

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.

Interest will be paid in kind on December 31, 2025 and March 31, 2026 with cash interest payments beginning on June 30, 2026.

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.

On September 14, 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 KKR 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.

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 KKR 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 I of this Quarterly Report on Form 10-Q.

On May 8, 2024, we entered into a credit and guaranty agreement (the “Credit Agreement”) with certain existing lenders and HCRx, which was subsequently assigned by HCRx to KKR in connection with its acquisition of a majority ownership stake in HCRx in July 2025, 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 with the lenders party thereto and Wilmington Savings Fund Society, FSB, as administrative agent for the lenders and collateral agent (the “Amended Credit Agreement”), pursuant to which, among other things, the lenders provided $12.5 million principal amount of additional loans (the “Amended Term Loan”).

The amendments to the Credit Agreement include, among other things (i) reducing the financial covenant requiring us to maintain liquidity of at least $10.0 million, subject to increase in the event we issue indebtedness for borrowed money or issue capital stock, 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 October 10, 2025 were paid in kind at closing.

Interest on borrowings will be paid in kind on December 31, 2025 and March 31, 2026 and cash interest payments will begin on June 30, 2026.

For additional information, see Note 10, “ Long-Term Obligations ”, to the condensed consolidated financial statements included under Part I, Item I of this Quarterly Report on Form 10-Q.

On February 17, 2023, we entered into an Open Market Sale Agreement (the “2023 Open Market Sale Agreement”) with Jefferies LLC, as agent (“Jefferies”).

Under the 2023 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.

We did not sell any Shares under the 2023 Open Market Sales Agreement during the three and nine months ended September 30, 2025 and 2024.

As of September 30, 2025, $100.0 million of Shares was available for issuance and sale under the 2023 Open Market Sale Agreement.

During the nine months ended September 30, 2025, we received $8.2 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.

In addition, under the license agreement we entered into with Menarini in December 2021 (the “Menarini Agreement”), Menarini is required to reimburse us for 25% of all documented expenses we incur for the global development of selinexor from 2022 through 2025, provided that such reimbursements shall not exceed $15.0 million per calendar year.

We received $13.5 million of reimbursements under the Menarini Agreement during the nine months ended September 30, 2025.

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 was subsequently assigned by HCRx to KKR in connection with its acquisition of a majority ownership stake in HCRx in July 2025, 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 March 31, 2026 were paid in kind.

Interest on borrowings incurred from April 1, 2026 to June 30, 2026 will be paid in kind on June 30, 2026 and cash interest payments will begin 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 three months ended March 31, 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 three months ended March 31, 2025.

As of March 31, 2026, $79.8 million of Shares was available for issuance and sale under the Open Market Sale Agreement.

During the three months ended March 31, 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 98,502 square feet of research and office space through September 30, 2025, which will be reduced to 52,224 square feet of solely office space from October 1, 2025 through September 30, 2030.

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

We currently have contractual obligations under our (i) Amended Credit Agreement;

We have contractual obligations under our (i) Amended Credit Agreement;

(ii) 2028 Notes;

(iii) 2029 Notes;

and (iv) Amended Revenue Interest Agreement as disclosed in Note 10, “ Long-Term Obligations ” and Note 12, “ Subsequent Event ”, to the condensed consolidated financial statements included under Part I, Item 1 of this Quarterly Report on Form 10-Q.

(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 lead clinical programs in myelofibrosis and our other late-stage clinical programs in endometrial cancer and multiple myeloma, as well as 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.

We expect to continue to incur costs related to our clinical development programs as we continue to advance our lead clinical programs in myelofibrosis and endometrial cancer and our other late-stage clinical program in multiple myeloma, as well as 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.

Identifying potential product candidates and conducting preclinical studies and clinical trials is a time-consuming, expensive and uncertain process that takes years to complete.

1 unchanged sentence

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 for several years, 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.

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.

1 unchanged sentence

We may seek additional capital due to favorable market conditions or strategic considerations, even if we believe we have sufficient funds for our current or future operating plans.

If we are unable to raise capital or enter into strategic alternatives sufficient to meet our needs or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs or commercialization efforts.

See Note 1 “ Nature of Business, Basis of Presentation and Segment Information ” to the condensed consolidated financial statements included under Part I, Item I 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 currently expect that our existing 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 the second quarter of 2026.

We will require additional capital to complete the ongoing clinical development of selinexor, including the Phase 3 SENTRY trial beyond top-line results and the Phase 3 XPORT-EC-042 trial.

If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs or commercialization efforts.

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 currently expect that our existing liquidity, including cash and cash equivalents as well as cash flow from net product revenue and license and other revenue, will enable us to fund our current operating plans to late in the third quarter of 2026.

We will require additional capital to fund the ongoing clinical development of selinexor and other product candidates and to pursue potential regulatory approvals.

We plan to address the conditions that raise substantial doubt regarding our ability to continue as a going concern by, among other things, obtaining additional funding through equity offerings, debt financings and refinancings, collaborations, strategic alliances and/or licensing arrangements.

We expect to evaluate opportunities to raise additional funds from time to time, including though the issuance and sale of shares of our common stock under our 2023 Open Market Sale Agreement with Jefferies and in connection with the reporting of data from our ongoing Phase 3 clinical trials.

We expect to evaluate opportunities to raise additional funds from time to time, including through the issuance and sale of shares of our common stock under our Open Market Sale Agreement and in

connection with the reporting of data from our ongoing Phase 3 XPORT-EC-042 trial.

There is no assurance that such additional financing or strategic alternatives will be available on terms acceptable to us, or at all.

2 unchanged sentences

Bankruptcy Code.

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 Term Loan, the 2029 Notes, the 2025 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.

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.

1 unchanged sentence

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 delay, reduce or eliminate our research and development programs and/or commercialization efforts ,” under 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 current funding requirements, following the Financing Transactions that occurred in October 2025, also include the following:

• Lease costs of our headquarters in Newton, Massachusetts of $9.7 million through September 30, 2030;

In addition to the expenses required to fund our operations described above, our funding requirements as of March 31, 2026 also include the following:

• Lease costs for our headquarters in Newton, Massachusetts of $8.9 million through September 30, 2030;

• Future obligations related to the Amended Credit Agreement of $153.5 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 2029 Notes of $136.1 million through May 13, 2029;

• Future obligations related to the New 2029 Notes of $138.3 million through May 13, 2029;

• Future royalty obligations to KKR under the Amended Revenue Interest Agreement of $116.2 million by October 1, 2035.

1 unchanged sentence

We are exposed to market risk related to changes in interest rates.

We had cash, cash equivalents and investments of $45.9 million as of September 30, 2025.

We had cash and cash equivalents of $90.9 million as of March 31, 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 investment portfolio.

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.

We do not believe our cash and cash equivalents have significant risk of default or illiquidity.

While we believe our cash and cash equivalents 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.

5 unchanged sentences

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-Q

Item 2. Management’s Discussion and Analysis