Company: SUPN
Filing Date: 2025-07-31
Form Type: SC TO-T/A
Source: 0001104659-25-072515
Chunk: 0

Company: SUPERNUS PHARMACEUTICALS, INC.
Filing Date: 2025-07-31
Form: SC TO-T/A
Chunk 0
---
<div align='center'>UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE TO

Tender Offer Statement under Section 14(d)(1) or 13(e)(1)

of the Securities Exchange Act of 1934

(Amendment No. 2)

SAGE THERAPEUTICS, INC.

(Name of Subject Company (Issuer))

SAPHIRE, INC.

(Offeror)

A Wholly Owned Subsidiary of

SUPERNUS PHARMACEUTICALS, INC.

(Parent of Offeror)

(Names of Filing Persons)

Common Stock par value $0.0001 per share

(Title of Class of Securities)

78667J108

(CUSIP Number of Class of Securities)

Timothy C. Dec

Senior Vice President and Chief Financial Officer

Supernus Pharmaceuticals, Inc.

9715 Key West Ave

Rockville, Maryland 20850

Telephone: (301) 838-2500

(Name, address, and telephone number of person authorized to receive notices and communications on behalf of filing persons)

With copies to:

Mark I. Gruhin, Esq.

George A. Naya, Esq.

Saul Ewing LLP

1919 Pennsylvania Avenue NW, Suite 550

Washington, DC 20006

Telephone: (202) 333-8800</div>

| ¨ | 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: |

| x | 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: x

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)      |
| ¨ | Rule 14d-1(d) (Cross-Border Third-Party Tender Offer) |

This Amendment No. 2 (this“ Amendment”) amends and supplements