SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 23)

Madrigal Pharmaceuticals, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

558868 105

(CUSIP Number)

Mr. Heath N. Weisberg

Caxton Corporation

731 Alexander Road, Bldg. 2

Princeton, New Jersey 08540

(212) 205-6805

(Name, Address and Telephone Number of Person Authorized to

Receive Notices and Communications)

July 28, 2016

(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 Section 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 Section

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 ("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).

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Caxton Corporation 22-2437619
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) [_]
		(b) [X]
3.	SEC USE ONLY
4.	SOURCE OF FUNDS
	AF
5.	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)	[_]
6.	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON
7.	SOLE VOTING POWER
	0
8.	SHARED VOTING POWER
	318,068
9.	SOLE DISPOSITIVE POWER
	0
10.	SHARED DISPOSITIVE POWER
	318,068
11.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	318,068
12.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	[_]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	2.8%
14.	TYPE OF REPORTING PERSON
	CO

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Kovner 2012 Family Trust B
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) [_]
		(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)	[_]
6.	CITIZENSHIP OR PLACE OF ORGANIZATION
	New York
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON
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	[_]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	0%
14.	TYPE OF REPORTING PERSON
	OO

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Kovner 2015-A Investment Trust
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) [_]
		(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)	[_]
6.	CITIZENSHIP OR PLACE OF ORGANIZATION
	New York
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON
7.	SOLE VOTING POWER
	0
8.	SHARED VOTING POWER
	114,285
9.	SOLE DISPOSITIVE POWER
	0
10.	SHARED DISPOSITIVE POWER
	114,285
11.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	114,285
12.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	[_]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	1.0%
14.	TYPE OF REPORTING PERSON
	OO

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	OB Select Opportunities, LLC 22-3623004
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) [_]
		(b) [X]
3.	SEC USE ONLY
4.	SOURCE OF FUNDS
	WC
5.	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)	[_]
6.	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON
7.	SOLE VOTING POWER
	0
8.	SHARED VOTING POWER
	17,158
9.	SOLE DISPOSITIVE POWER
	0
10.	SHARED DISPOSITIVE POWER
	17,158
11.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	17,158
12.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	[_]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	0.2%
14.	TYPE OF REPORTING PERSON
	OO

 

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	KFO HOLDINGS LLC 46-4139835
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) [_]
		(b) [X]
3.	SEC USE ONLY
4.	SOURCE OF FUNDS
	WC
5.	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)	[_]
6.	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON
7.	SOLE VOTING POWER
	0
8.	SHARED VOTING POWER
	299,257
9.	SOLE DISPOSITIVE POWER
	0
10.	SHARED DISPOSITIVE POWER
	299,257
11.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	299,257
12.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	[_]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	2.6%
14.	TYPE OF REPORTING PERSON
	OO

 

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Kovner, Bruce
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) [_]
		(b) [X]
3.	SEC USE ONLY
4.	SOURCE OF FUNDS
	AF, PF
5.	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)	[_]
6.	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON
7.	SOLE VOTING POWER
	90,419
8.	SHARED VOTING POWER
	432,353
9.	SOLE DISPOSITIVE POWER
	90,419
10.	SHARED DISPOSITIVE POWER
	432,353
11.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	522,772
12.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	[_]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	4.6%
14.	TYPE OF REPORTING PERSON
	IN

 

ITEM 1.

Security and Issuer

This Schedule 13D relates to the common stock (the "Common Stock"), of Madrigal Pharmaceuticals, Inc. (the "Company") formerly known as "Synta Pharmaceuticals Corp." The principal executive office of the Company is located at 500 Office Center Drive, Suite 400, Fort Washington, Pennsylvania.

On July 22, 2016, Synta Pharmaceuticals Corp. completed its business combination with the Company, in accordance with the terms of the Agreement and Plan of Merger and Reorganization, dated as of April 13, 2016 (the "Merger"). Also on July 22, 2016, in connection with, and prior to completion of, the Merger, Synta Pharmaceuticals Corp. effected a 1-for-35 reverse stock split of its common stock and, following the Merger, changed its name to "Madrigal Pharmaceuticals, Inc."

ITEM 2.

Identity and Background

Item 2 is hereby amended and replaced by the following:

(b)  (i)

The address of Caxton Corporation is 731 Alexander Road, Bldg. 2 Princeton, NJ 08540.

(ii)

The address of Kovner 2012 Family Trust B is 731 Alexander Road, Bldg. 2 Princeton, NJ 08540.

(iii)

The address of Kovner 2015-A Investment Trust is 731 Alexander Road, Bldg. 2 Princeton, NJ 08540.

(iv)

The address of OB Select Opportunities, LLC is 731 Alexander Road, Bldg. 2 Princeton, NJ 08540.

(v)

The address of KFO Holdings LLC is 731 Alexander Road, Bldg. 2 Princeton, NJ 08540.

(vi)

The business address of Mr. Kovner is 731 Alexander Road, Bldg. 2 Princeton, NJ 08540.

(c)  (i)

The principal business of Caxton Corporation is to serve as the manager of certain investment vehicles controlled by Mr. Kovner, including OB Select Opportunities, LLC and KFO Holdings LLC, and as general partner of Caxton Alternative Management LP, an affiliate of Caxton Corporation.

(ii)

The principal business of Kovner 2012 Family Trust B is to serve as an estate planning vehicle for Mr. Kovner and his family.

(iii)

The principal business of Kovner 2015-A Investment Trust is to serve as an estate planning vehicle for Mr. Kovner and his family.

(iv)

The principal business of OB Select Opportunities, LLC is to serve as an investment vehicle for investments in securities.

(v)

The principal business of KFO Holdings LLC is to serve as an investment vehicle for investments in securities.

(vi)

The present principal occupation of Mr. Kovner is Chairman of Caxton Corporation and Caxton Alternative Management LP.

(i)

Caxton Corporation – Delaware.

(ii)

Kovner 2012 Family Trust B – New York.

(iii)

Kovner 2015-A Investment Trust – New York.

(iv)

OB Select Opportunities, LLC – Delaware.

(v)

KFO Holdings LLC – Delaware.

(vi)

Mr. Kovner – United States.

ITEM 3.

Source and Amount of Funds or Other Consideration.

Item 3 is hereby amended by adding the following thereto:

No change from the Schedule 13D/A filed on July 26, 2016.

ITEM 4.

Purpose of Transaction.

Item 4 is hereby amended and replaced by the following:

Each of the shares of Common Stock of the Company that are indicated herein were acquired for investment purposes.  Based on a review of the investment, certain of the Reporting Persons may, in the open market or otherwise, dispose of, or cause to be disposed of, a material portion of Common Stock or other securities of the Company, or derivatives or other instruments related to the securities of the Company.

On July 22, 2016, effective immediately prior to the effective time of the Merger, Mr. Kovner and Scott Morenstein, an employee of Caxton Alternative Management LP, resigned as Directors of the Company.  Caxton Alternative Management LP is an affiliate of Caxton Corporation, which is a Reporting Person.

Except as set forth in this Schedule 13D, none of the Reporting Persons has any plans or proposals that relate to any of the matters referred to in paragraphs (a) through (j) of the instructions to Item 4 of Schedule 13D.

ITEM 5.

Interest in Securities of the Issuer.

Subparagraph (a), (b) and (c) of Item 5 of the Schedule 13D is hereby amended and replaced by the following:

Caxton Corporation disclaims beneficial ownership of the shares of Common Stock owned directly by KFO Holdings LLC, OB Select Opportunities, LLC, and an employee of an affiliate of Caxton Corporation, except to the extent of its pecuniary interest therein.

As a result of the foregoing, Mr. Kovner may be deemed to beneficially own an aggregate of 522,772 shares of Common Stock, representing approximately 4.6% of the 11,335,873¹ total shares of Common Stock deemed issued and outstanding.

Mr. Kovner disclaims beneficial ownership of the shares of Common Stock owned directly by KFO Holdings LLC, OB Select Opportunities, LLC and an employee of an affiliate of Caxton Corporation, except to the extent of his pecuniary interest therein.  Mr. Kovner also disclaims beneficial ownership of the shares of Common Stock directly owned by the Kovner 2015-A Investment Trust.

Except as reported in this statement on Schedule 13D, the Reporting Persons are not believed to have engaged in any other transactions in the Company's securities since the most recent filing of Schedule 13D.

ITEM 6.

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

No additional amendments to Item 6 of the Schedule 13D.

ITEM 7.

Material to Be Filed as Exhibits

Exhibit A: Transactions by the Reporting Persons since the most recent filing of Schedule 13D.

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¹ The number of issued and outstanding shares is based on the 11,333,816 shares of Common Stock reported to be outstanding in the Company's 8-K as of July 22, 2016 (immediately following the reverse stock split and the Merger), adjusted for options held by Mr. Kovner.

 

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: 8/1/2016	Caxton Corporation
	/s/ Heath N. Weisberg
	Heath N. Weisberg, as General Counsel and Chief Compliance Officer of Caxton Corporation
Date: 8/1/2016	Kovner 2012 Family Trust B
	/s/ Karen Cross
	Karen Cross, Vice President and Treasurer of Cadence Trust Company
Date: 8/1/2016	Kovner 2015-A Investment Trust
	/s/ Karen Cross
	Karen Cross, Vice President and Treasurer of Cadence Trust Company
Date: 8/1/2016	OB Select Opportunities, LLC
	By: Caxton Corporation, Manager of OB Select Opportunities, LLC
	/s/ Heath N. Weisberg
	Heath N. Weisberg, as General Counsel and Chief Compliance Officer of Caxton Corporation
Date: 8/1/2016	KFO Holdings LLC
	By: Caxton Corporation, Manager of KFO Holdings LLC
	/s/ Heath N. Weisberg
	Heath N. Weisberg, General Counsel and Chief Compliance Officer of Caxton Corporation
Date: 8/1/2016	Bruce S. Kovner
	/s/ Heath N. Weisberg
	Heath N. Weisberg, as attorney in fact for Bruce Kovner

The original statement shall be signed by each person on whose behalf the statement is filed or his authorized representative. If the statement is signed on behalf of a person by his authorized representative (other than an executive officer or general partner of the filing person), evidence of the representative's authority to sign on behalf of such person shall be filed with the statement: provided, however, that a power of attorney for this purpose which is already on file with the Commission may be incorporated by reference.  The name and any title of each person who signs the statement shall be typed or printed beneath his signature.

ATTENTION: Intentional misstatements or omissions of fact constitute Federal criminal violations (See 18 U.S.C. 1001).

Exhibit A

Transactions by the Reporting Persons since the most recent filing of Schedule 13D

TRANSACTIONS BY KOVNER 2012 FAMILY TRUST B
Date of Transaction	Number of Shares Purchase/(Sold)	Price of Shares
7/26/2016	(3,545)	$9.7832
7/27/2016	(4,572)	$8.00

TRANSACTIONS BY BRUCE KOVNER
Date of Transaction	Number of Shares Purchase/(Sold)	Price of Shares
7/27/2016	(31,119)2	$7.7051
7/27/2016	(5,428)2	$8.00
7/27/2016	(2,313)2	$7.7051
7/28/2016	(15,000)2	$7.7846
7/29/2016	(11,258)2	$7.5151

TRANSACTIONS BY KFO HOLDINGS LLC
Date of Transaction	Number of Shares Purchase/(Sold)	Price of Shares
7/29/2016	(26,441)	$7.5151

 

 

 

 

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²These shares were sold by an estate planning vehicle of Mr. Kovner's spouse.