Karyopharm forbearance extended up to November 1

The revised end time is 11:59 p.m. Eastern on November 1, 2026, subject to earlier termination.

Rhea-AI Filing Summary

Karyopharm Therapeutics Inc. (KPTI) said the applicable parties further extended the Forbearance Period under the Forbearance Agreement and Limited Waiver to Indentures. The period will end at 11:59 p.m. Eastern time on November 1, 2026, absent earlier termination, replacing the prior end time of 11:59 p.m. Eastern time on October 22, 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

Forbearance Agreement date: September 10, 2026 Prior Forbearance Period end: October 22, 2026, at 11:59 p.m. Eastern time Extended Forbearance Period end: November 1, 2026, at 11:59 p.m. Eastern time

3 metrics

Forbearance Agreement date September 10, 2026 Date of the Forbearance Agreement and Limited Waiver to Indentures

Prior Forbearance Period end October 22, 2026, at 11:59 p.m. Eastern time End time before the further extension

Extended Forbearance Period end November 1, 2026, at 11:59 p.m. Eastern time Subject to earlier termination

Key Terms

Forbearance Agreement, Forbearance Period, Indentures

3 terms

Forbearance Agreement financial

"entered into a Forbearance Agreement and Limited Waiver to Indentures"

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.

Forbearance Period financial

"extended 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.

Indentures financial

"Forbearance Agreement and 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 11:59 p.m. Eastern time on November 1, 2026, absent earlier termination; this replaced the prior end time of 11:59 p.m. Eastern time on October 22, 2026.

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

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Available on EDGAR 10/22/2026 - 04:15 PM EDT Accepted by SEC EDGAR 10/22/2026 - 04:15 PM EDT Learn about SEC filing dates

false 0001503802 0001503802 2026-10-22 2026-10-22

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 22, 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 Events.

As previously disclosed in the Current Reports on Form 8-K filed by Karyopharm Therapeutics Inc. (the “Company”) on September 11, 2026 and October 14, 2026, the Company entered into a Forbearance Agreement and Limited Waiver to Indentures, dated September 10, 2026 (the “Forbearance Agreement”), and the applicable parties subsequently extended the Forbearance Period (as defined in the Forbearance Agreement) to October 22, 2026.

On October 22, 2026, in accordance with Section 19 of the Forbearance Agreement, the applicable parties further extended the date on which the Forbearance Period will end, absent earlier termination, from 11:59 p.m., Eastern time, on October 22, 2026 to 11:59 p.m., Eastern time, on November 1, 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 22, 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