Karyopharm extends forbearance up to October 22

The extended Forbearance Period is scheduled to run through October 22, 2026, unless it ends earlier.

Rhea-AI Filing Summary

Karyopharm Therapeutics Inc. (KPTI) disclosed that the applicable parties extended the end of the Forbearance Period under its Forbearance Agreement and Limited Waiver to Indentures. The period will end at 11:59 p.m. Eastern time on October 22, 2026, absent earlier termination, instead of October 15, 2026.

8-K Event Classification

Item 8.01 — Other Events

1 item

Item 8.01 Other Events Other

Voluntary disclosure of events the company deems important to shareholders but not covered by other items.

Key Figures

Revised Forbearance Period end: October 22, 2026, at 11:59 p.m. Eastern time Previous Forbearance Period end: October 15, 2026, at 11:59 p.m. Eastern time Forbearance Agreement date: September 10, 2026 +1 more

4 metrics

Revised Forbearance Period end October 22, 2026, at 11:59 p.m. Eastern time Extended end date, absent earlier termination

Previous Forbearance Period end October 15, 2026, at 11:59 p.m. Eastern time End date before the extension

Forbearance Agreement date September 10, 2026 Date of the agreement

Prior disclosure date September 11, 2026 Date the company previously disclosed the agreement

Key Terms

Forbearance Period, Forbearance Agreement, Limited Waiver, Indentures

4 terms

Forbearance Period financial

"the date on which the Forbearance Period will end"

A forbearance period is a temporary agreement that allows a borrower to pause, reduce or delay loan payments while they recover from short-term financial strain. For investors, it signals changed near-term cash flows and higher uncertainty about repayment—like hitting a pause button on expected income—so it can affect loan valuations, credit risk assessments and the timing of potential losses or recoveries.

Forbearance Agreement financial

"entered into a Forbearance Agreement and Limited Waiver"

A forbearance agreement is a temporary deal between a borrower and a lender where the lender agrees to delay or reduce payments instead of declaring a default; think of it as a pause button on a loan while both sides work out a longer-term fix. It matters to investors because it affects a company’s short-term cash flow and the likelihood of loan losses or restructuring, which can change credit risk and share value.

Limited Waiver financial

"Forbearance Agreement and Limited Waiver to Indentures"

Indentures financial

"Limited Waiver to Indentures"

Indentures are the written contracts that set out the terms and protections for a debt issue, such as a bond or note, including payment schedule, interest rate, collateral, and what happens if the borrower misses payments. Think of it like the rulebook and safety features for a loan that both the borrower and lenders agree to; investors use it to assess their rights, recoveries in trouble, and limits on the issuer’s future actions.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

When does KPTI's Forbearance Period end?

The applicable parties extended the Forbearance Period to end at 11:59 p.m. Eastern time on October 22, 2026, absent earlier termination.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/14/2026 - 07:30 AM EDT Accepted by SEC EDGAR 10/14/2026 - 07:30 AM EDT Learn about SEC filing dates

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): October 13, 2026

Karyopharm Therapeutics Inc.

(Exact Name of Registrant as Specified in Charter)

Delaware		001-36167		26-3931704
(State or Other Jurisdiction of Incorporation)		(Commission File Number)		(IRS Employer Identification No.)

85 Wells Avenue, 2nd Floor Newton, Massachusetts		02459
(Address of Principal Executive Offices)		(Zip Code)

Registrant’s telephone number, including area code: (617) 658-0600

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, $0.0001 par value		KPTI		Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01. Other Items.

As previously disclosed in the Current Report on Form 8-K filed by Karyopharm Therapeutics Inc. (the “Company”) on September 11, 2026, the Company entered into a Forbearance Agreement and Limited Waiver to Indentures, dated September 10, 2026 (the “Forbearance Agreement”).

On October 13, 2026, in accordance with Section 19 of the Forbearance Agreement, the applicable parties extended the date on which the Forbearance Period (as defined in the Forbearance Agreement) will end, absent earlier termination, from 11:59 p.m., Eastern time, on October 15, 2026 to 11:59 p.m., Eastern time, on October 22, 2026.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

				KARYOPHARM THERAPEUTICS INC.
Date: October 14, 2026				By:		/s/ Michael Mano
						Michael Mano
						Executive Vice President, Chief Legal Officer and Secretary

Filing Exhibits & Attachments

3 documents

Other Documents

• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 3.1 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 17.6 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 11.0 KB