Karyopharm misses $15.8 million payment, agrees to $20 million preferred-stock forbearance fee

Karyopharm Therapeutics Inc. (NASDAQ: KPTI) entered a forbearance agreement on September 10 after missing an approximately $15.8 million principal installment under its Credit Agreement. Creditors agreed to hold off on enforcing specified defaults for a period scheduled to end at 11:59 p.m. ET on October 15, 2026, subject to earlier termination or an extension under the agreement. The company also agreed to $20.0 million in fees payable in newly created convertible preferred stock.

The agreement gives Karyopharm time to advance its myelofibrosis program, negotiate with lenders, pursue strategic alternatives or raise equity capital. The deadline also marks the company's expected cash runway: assuming the forbearance lasts through October 15, Karyopharm expects existing liquidity and net product and license revenue to fund current operating plans until that date. Without additional funding or a strategic transaction beyond then, it says it will be unable to continue as a going concern.

Forbearance does not erase the missed payments. The creditors have temporarily agreed not to exercise remedies solely for the specified defaults; those defaults are not waived, payment deadlines are not extended and creditors retain their rights.

- **Approximately $15.8 million:** Credit Agreement principal installment due September 10, 2026 that Karyopharm did not pay. - **October 15, 2026, 11:59 p.m. ET:** Scheduled forbearance end, subject to earlier termination triggers or extension as specified. - **$20.0 million:** Agreed fees payable in 20,000 preferred shares at $1,000 per share; issuance expected September 17, 2026. - **Approximately $129.0 million:** Term-loan principal outstanding as of September 10, 2026, excluding interest after June 30, 2026.

The agreement includes Karyopharm and subsidiary guarantors, lenders under its Credit and Guaranty Agreement, holders of all outstanding 9.00% convertible senior notes due in 2028 and 2029, and the investor representative under its revenue interest financing agreement. Wilmington Savings Fund Society, FSB participates in agent and trustee capacities for specified provisions.

Alongside the missed principal installment, Karyopharm does not expect to pay cash interest due September 30 under the Credit Agreement and the note indentures. It also missed June 30 cash interest payments on the notes and may not meet the $25.0 million minimum liquidity covenant that applies after October 10. These matters constitute specified defaults or will do so when applicable grace periods expire.

The October 15 endpoint is conditional. The period can end earlier upon a bankruptcy- or insolvency-related default, material enforcement by a creditor, or termination or expiration of another material forbearance. Specified events can also lead to a termination notice, including other defaults, a breach of the agreement, a material adverse effect or consolidated liquidity falling below $10.0 million. FDA refusal to accept for filing the supplemental new drug application for selinexor plus ruxolitinib in myelofibrosis—or the company's withdrawal of that application—is another such trigger. That condition concerns acceptance for filing, not a determination of clinical success.

When forbearance ends, overdue amounts become immediately due and payable in cash, and creditors may exercise remedies including acceleration. Payment defaults also carry additional interest: Credit Agreement obligations bear an extra 2.00 percentage points annually while the relevant payment default continues, starting September 10 for the unpaid principal installment and September 30 for unpaid term-loan interest. Defaulted note amounts bear an additional 2.00% annually from the unpaid interest payment dates.

Karyopharm agreed to pay aggregate fees of $20.0 million in 20,000 shares of new 0% convertible perpetual preferred stock, valued at $1,000 per share with a $1,000 liquidation preference. Those fees, together with interest at the Notes Forbearance Rate, constitute the Forbearance Consideration. The company expects to issue the preferred shares on September 17 after filing the certificate of designations.

The preferred stock converts into common stock at $1.62 per share, subject to anti-dilution adjustments but without a ratchet for future equity raises. Until stockholders consent to issuance of all conversion shares, conversion is limited to 19.99% of common-stock voting power at issuance. Any excess is settled in cash using a 20-day volume-weighted average price. The consent deadline is no later than March 15, 2027.

Holders have a third-anniversary put at $1,000 per share, and the terms provide for redemption at Liquidation Value upon a Fundamental Change. The preferred shares will be issued in a private placement to accredited investors under Section 4(a)(2) of the Securities Act.

As of September 10, Karyopharm had approximately $129.0 million of term-loan principal outstanding, plus $15.6 million of 2028 notes and $108.0 million of 2029 notes, excluding interest after June 30. Approximately $2.8 million of note interest due June 30 remained unpaid and bears an additional 2.00% annually from that date. Future royalty obligations totaled $113.5 million.

The company's going-concern warning makes the next financing or strategic decision consequential. If additional funding or a strategic transaction does not support operations beyond October 15, Karyopharm says it may consider bankruptcy protection, liquidating assets or ceasing operations. The agreement provides a limited period to pursue those alternatives while leaving the underlying defaults and payment obligations in place.

Filing path

Karyopharm disclosed the forbearance and preferred-stock fee in Form 8-K AccNo 0001193125-26-388621 under Items 1.01, 2.04, 3.02, 8.01 and 9.01, with an earliest event date of September 10, 2026 and filing on September 11, 2026.