UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO

RULE 13d-2(a)

(Amendment No. 1)*

Ambit Biosciences Corporation

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

02318X 10 0

(CUSIP Number)

Lloyd Appel

Aisling Capital

888 Seventh Avenue, 30th Floor

New York, NY 10106

(212) 651-6380

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

November 10, 2014

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box ¨.

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (the “Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 02318X 10 0

SCHEDULE 13D

Page 2 of 10

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Perseus-Soros BioPharmaceutical Fund, LP
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) o (b) x
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON PN

CUSIP No. 02318X 10 0

SCHEDULE 13D

Page 3 of 10

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Perseus-Soros Partners, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) o (b) x
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON OO

CUSIP No. 02318X 10 0

SCHEDULE 13D

Page 4 of 10

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Aisling Capital LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) o (b) x
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON OO

CUSIP No. 02318X 10 0

SCHEDULE 13D

Page 5 of 10

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Steve Elms
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) o (b) x
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 1,670,676

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON IN

CUSIP No. 02318X 10 0

SCHEDULE 13D

Page 6 of 10

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Dennis Purcell
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) o (b) x
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON IN

CUSIP No. 02318X 10 0

SCHEDULE 13D

Page 7 of 10

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Andrew Schiff
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) o (b) x
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON IN

CUSIP No. 02318X 10 0

SCHEDULE 13D

Page 8 of 14

Item 1. Security and Issuer.

Item 1 is amended and restated in its entirety as follows:

This Amendment No. 1 to Schedule 13D (this “Statement”) amends and supplements the Schedule 13D as previously filed with the Securities and Exchange Commission on May 31, 2013, by the undersigned Reporting Persons, with respect to common stock, par value $0.001 per share (the “Common Stock”) of Ambit Biosciences Corporation (the “Issuer”). The principal executive offices of the Issuer are located at 11080 Roselle St., San Diego, California 92121.

This Amendment No. 1 is being filed to report that on November 10, 2014, the Reporting Persons ceased to be the beneficial owner of more than 5% of the Common Stock of the Issuer as a result of the Closing of the Tender Offer (each as defined below).

Item 2. Identity and Background.

No material change.

Item 3. Source and Amount of Funds or Other Consideration.

Item 3 is hereby amended and replaced as follows:

As of the date hereof, none of the Reporting Persons may be deemed to beneficially own any shares of Common Stock (including, for the avoidance of doubt, warrants to acquire shares of Common Stock).

CUSIP No. 02318X 10 0

SCHEDULE 13D

Page 9 of 10

Item 4. Purpose of Transaction.

No material change

Item 5. Interest in Securities of the Issuer.

Item 5 is hereby amended and replaced as follows:

(a), (b) As of November 10, 2014, upon the closing (the “Closing”) of the tender offer (the “Tender Offer”) contemplated by the agreement and plan of merger by and among the Issuer, Daiichi Sankyo Company, Limited and Charge Acquisition Corp., dated September 28, 2014, none of the Reporting Persons had any beneficial interest, or sole or shared power to vote or dispose of any shares of Common Stock.

(c) On November 10, 2014, upon the Closing all of the 1,650,156 shares of Common Stock owned of record by PSBF were acquired by Charge Acquisition Corp. at a purchase price of (a) $15.00 per share, without interest (the “Cash Consideration”) plus (b) one non-transferable contingent value right per share (each, a “CVR”), which represents the right to receive contingent payments of $4.50 in cash in the aggregate, if any, without interest, subject to the achievement of certain specified milestones, subject to and in accordance with certain terms and conditions set forth in the agreements governing the CVRs and the offer to purchase and letter of transmittal governing the Tender Offer.

In addition, on November 10, 2014, each of the 20,520 warrants to purchase shares of the Company’s Common Stock held of record by PSBR was cancelled without consideration.

(d) Not applicable.

(e) On November 10, 2014, the Reporting Persons ceased to be the beneficial owner of more than 5% of the Issuer’s securities.

Item 6.

Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

No material change.

Item 7. Material Filed as Exhibits.

Exhibit 1:

Joint Filing Agreement dated as of May 31, 2013, as required by Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended (as previously filed).

CUSIP No. 02318X 10 0

SCHEDULE 13D

Page 10 of 10

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: Novenber 19. 2014

	PERSEUS-SOROS BIOPHARAMCEUTICAL FUND, LP
By:	Perseus-Soros Partners, LLC
	General Partner

By:	Aisling Capital LLC
	Managing Member

	By:	/s/ Dennis Purcell
		Name: Dennis Purcell
		Title: Managing Member

	PERSEUS-SOROS PARTNERS, LLC
By:	Aisling Capital LLC
	Managing Member

	By:	/s/ Dennis Purcell
		Name: Dennis Purcell
		Title: Managing Member

		AISLING CAPITAL LLC
	By:	/s/ Dennis Purcell
		Name: Dennis Purcell
		Title: Managing Member

	By:	/s/ Steve Elms
		Name: Steve Elms
		Title: Managing Member

	By:	/s/ Andrew Schiff
		Name: Andrew Schiff
		Title: Managing Member

Attention. Intentional misstatements or omissions of fact constitute Federal criminal violations (see 18 U.S.C. 1001).

AMBIT BIOSCIENCES CORP SC 13D/A