Company: SUPN
Filing Date: 2025-07-02
Form Type: SC TO-T
Source: 0001104659-25-065398
Chunk: 0

Company: SUPERNUS PHARMACEUTICALS, INC.
Filing Date: 2025-07-02
Form: SC TO-T
Chunk 0
---
### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

### SCHEDULE TO
<div align='center'>**Tender Offer Statement under Section 14(d)(1) or 13(e)(1)**</div>

#### of the Securities Exchange Act of 1934

#### SAGE THERAPEUTICS, INC.
<div align='center'>(Name of Subject Company (Issuer))</div>

#### Saphire, Inc.
<div align='center'>(Offeror) 
 A Wholly Owned Subsidiary of</div>

#### SUPERNUS PHARMACEUTICALS, INC.
<div align='center'>(Parent of Offeror)</div>

#### Common Stock par value $0.0001 per share
<div align='center'>(Title of Class of Securities)</div>

#### 78667J108
<div align='center'>(CUSIP Number of Class of Securities)</div>

#### Timothy C. Dec

### Senior Vice President and Chief Financial Officer

#### Supernus Pharmaceuticals, Inc.

#### 9715 Key West Ave

#### Rockville, Maryland 20850

#### Telephone: (301) 838-2500
<div align='center'>**(Name, address, and telephone number of person authorized to receive notices and communications on behalf of filing persons)

With copies to:**</div>

#### Mark I. Gruhin, Esq.

#### George A. Naya, Esq.

#### Saul Ewing LLP

#### 1919 Pennsylvania Avenue NW, Suite 550

#### Washington, DC 20006

#### Telephone: (202) 333-8800
□

Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

☒

Third-party tender offer subject to Rule 14d-1.

☐

Issuer tender offer subject to Rule 13e-4.

☐

Going-private transaction subject to Rule 13e-3.

☐

Amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer: ☐

If applicable, check the appropriate box(es) below to designate the appropriate rule provision(s) relied upon:

□

Rule 13e-4(i) (Cross-Border Issuer Tender Offer)

□