SUPN

supn-20260224false000135657600013565762026-02-242026-02-24

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 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): February 24, 2026

Supernus Pharmaceuticals, Inc.

(Exact name of registrant as specified in its charter)

Delaware 001-3551820-2590184 (State or other jurisdiction of incorporation or organization) (Commission File Number) (I.R.S. Employer Identification No.)

9715 Key West AveRockville MD 20850

(Address of Principal Executive Offices) (Zip Code)

Registrant’s telephone number, including area code: (301) 838-2500

Not Applicable (Former name or former address, if changed since last report.)

Securities registered pursuant to Section 12(b) of the Exchange Act Title of each classTrading SymbolName of each exchange on which registered Common Stock, $0.001 par value per shareSUPNThe Nasdaq Stock Market LLC

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))

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). ☐

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 2.02 Results of Operations and Financial Condition.

On February 24, 2026, Supernus Pharmaceuticals, Inc. (“Supernus” or the “Company”) issued a press release regarding its financial results for the fourth quarter ended December 31, 2025. A copy of this press release is furnished as Exhibit 99.1 hereto and is incorporated herein by reference.

As previously announced, Supernus is hosting a conference call at 4:30 p.m. Eastern Time on Tuesday, February 24, 2026, to present the business and financial results. A live webcast is available at www.supernus.com. The webcast will be archived on the Company’s website for 60 days following the live call.

The information in Items 2.02 (including Exhibit 99.1) is being “furnished” and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, whether made before or after the date of this report, except as shall be expressly set forth by specific reference in such filing.

This Current Report on Form 8-K contains “forward-looking statements” that do not convey historical information, but relate to predicted or potential future events, such as statements of our plans, strategies and intentions. These statements can often be identified by the use of forward-looking terminology such as “believe,” “expect,” “intend,” “may,” “will,” “should,” or “anticipate” or similar terminology. All statements other than statements of historical facts included in this Current Report on Form 8-K are forward-looking statements. All forward-looking statements speak only as of the date of this Current Report on Form 8-K. Except for Supernus’ ongoing obligations to disclose material information under the federal securities laws, Supernus undertakes no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. In addition to the risks and uncertainties of ordinary business operations and conditions in the general economy and the markets in which Supernus competes, the forward-looking statements of Supernus contained in this Current Report on Form 8-K are also subject to various risks and uncertainties, including those set forth in Item 1A, “Risk Factors,” in Supernus’ Annual Report on Form 10-K for the fiscal year ended December 31, 2024 which the Company filed on February 25, 2025, and other risk factors set forth from time to time in the Company’s filings with the Securities and Exchange Commission made pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended. Item 9.01 Financial Statements and Exhibits. (d) Exhibits

ExhibitDescription

99.1Press Release dated February 24, 2026 filed as an Exhibit

supn-20260212false000135657600013565762026-02-122026-02-12

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 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): February 12, 2026

Supernus Pharmaceuticals, Inc.

(Exact name of registrant as specified in its charter)

Delaware 001-3551820-2590184 (State or other jurisdiction of incorporation or organization) (Commission File Number) (I.R.S. Employer Identification No.)

9715 Key West AveRockville MD 20850

(Address of Principal Executive Offices) (Zip Code)

Registrant’s telephone number, including area code: (301) 838-2500

Not Applicable (Former name or former address, if changed since last report.)

Securities registered pursuant to Section 12(b) of the Exchange Act Title of each classTrading SymbolName of each exchange on which registered Common Stock, $0.001 par value per shareSUPNThe Nasdaq Stock Market LLC

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))

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). ☐

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 2.02 Results of Operations and Financial Condition. On February 12, 2026, Supernus Pharmaceuticals, Inc. issued a press release announcing that it expects to report its business results for the fourth quarter of 2025 after the market closes on Tuesday, February 24, 2026. The Company will host a conference call and webcast on Tuesday, February 24, 2026 at 4:30 p.m. E.T. to discuss its fourth quarter 2025 financial and business results. A copy of this press release is furnished as Exhibit 99.1 hereto and is incorporated herein by reference. Item 9.01 Financial Statements and Exhibits. (d) Exhibits

ExhibitDescription

99.1Press Release dated February 12, 2026 filed as an Exhibit pursuant to Item 2.02 hereof.

104The cover page from this Current Report on Form 8-K, formatted in Inline XBRL.

2

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.

SUPERNUS PHARMACEUTICALS, INC.

DATED: February 12, 2026By:/s/ Timothy C. Dec Timothy C. Dec Senior Vice President and Chief Financial Officer

3

supn-20251104false000135657600013565762025-11-042025-11-04

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 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): November 4, 2025

Supernus Pharmaceuticals, Inc.

(Exact name of registrant as specified in its charter)

Delaware 001-3551820-2590184 (State or other jurisdiction of incorporation or organization) (Commission File Number) (I.R.S. Employer Identification No.)

9715 Key West AveRockville MD 20850

(Address of Principal Executive Offices) (Zip Code)

Registrant’s telephone number, including area code: (301) 838-2500

Not Applicable (Former name or former address, if changed since last report.)

Securities registered pursuant to Section 12(b) of the Exchange Act Title of each classTrading SymbolName of each exchange on which registered Common Stock, $0.001 par value per shareSUPNThe Nasdaq Stock Market LLC

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))

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). ☐

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 2.02 Results of Operations and Financial Condition.

On November 4, 2025, Supernus Pharmaceuticals, Inc. (“Supernus” or the “Company”) issued a press release regarding its financial results for the third quarter September 30, 2025. A copy of this press release is furnished as Exhibit 99.1 hereto and is incorporated herein by reference.

As previously announced, Supernus is hosting a conference call at 4:30 p.m. Eastern Time on Tuesday, November 4, 2025, to present the business and financial results. A live webcast is available at www.supernus.com. The webcast will be archived on the Company’s website for 60 days following the live call.

Item 7.01 Regulation FD Disclosure.

On November 4, 2025, the Company announced that due to stronger than expected demand for ONAPGO, supplier constraints are impacting the Company’s ability to fully meet this demand. As a result of this supply imbalance, the Company is prioritizing care for patients currently on ONAPGO. This requires pausing delivery to patients who have not yet started ONAPGO. The Company is working to build adequate inventory and resume new patient initiations as soon as possible, and will provide timely updates as progress is made in resolving this supply constraint.

The information in Items 2.02 (including Exhibit 99.1) and Item 7.01 is being “furnished” and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, whether made before or after the date of this report, except as shall be expressly set forth by specific reference in such filing.

This Current Report on Form 8-K contains “forward-looking statements” that do not convey historical information, but relate to predicted or potential future events, such as statements of our plans, strategies and intentions. These statements can often be identified by the use of forward-looking terminology such as “believe,” “expect,” “intend,” “may,” “will,” “should,” or “anticipate” or similar terminology. All statements other than statements of historical facts included in this Current Report on Form 8-K are forward-looking statements. All forward-looking statements speak only as of the date of this Current Report on Form 8-K. Except for Supernus’ ongoing obligations to disclose material information under the federal securities laws, Supernus undertakes no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. In addition to the risks and uncertainties of ordinary business operations and conditions in the general economy and the markets in which Supernus competes, the forward-looking statements of Supernus contained in this Current Report on Fo