UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC  20549

SCHEDULE 13D

(Amendment No. 8)*

Under the Securities Exchange Act of 1934

INTREXON CORPORATION

(Name of Issuer)

Common Stock

(Title of Class of Securities)

46122T102

(CUSIP Number)

Third Security, LLC

1881 Grove Avenue

Radford, Virginia 24141

Attention: Marcus E. Smith, Esq.

(540) 633-7900

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

Copy to:

John Owen Gwathmey, Esq.

David I. Meyers, Esq.

Troutman Sanders LLP

Troutman Sanders Building

1001 Haxall Point

Richmond, Virginia 23219

(804) 697-1239

May 13, 2019

(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 which is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(b)(3) or (4), 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 (“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. 46122T102 Page 2 of 12

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
	RANDAL J. KIRK
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF GROUP			(a)	☐
				(b)	☒
3	SEC USE ONLY
4	SOURCE OF FUNDS
	PF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			70,439,882
		8	SHARED VOTING POWER
			0
		9	SOLE DISPOSITIVE POWER
			70,439,882
		10	SHARED DISPOSITIVE POWER
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	70,439,882
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	43.7%
14	TYPE OF REPORTING PERSON
	IN

CUSIP No. 46122T102 Page 3 of 12

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
	R.J. KIRK DECLARATION OF TRUST 31-6661283
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF GROUP			(a)	☐
				(b)	☒
3	SEC USE ONLY
4	SOURCE OF FUNDS
	PF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			16,924,973
		8	SHARED VOTING POWER
			0
		9	SOLE DISPOSITIVE POWER
			16,924,973
		10	SHARED DISPOSITIVE POWER
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	16,924,973
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	10.5%
14	TYPE OF REPORTING PERSON
	OO - trust

CUSIP No. 46122T102 Page 4 of 12

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
	THIRD SECURITY, LLC I.R.S. IDENTIFICATION NO.: 54-1923091
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF GROUP			(a)	☐
				(b)	☒
3	SEC USE ONLY
4	SOURCE OF FUNDS
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Virginia
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			53,368,111
		8	SHARED VOTING POWER
			0
		9	SOLE DISPOSITIVE POWER
			53,368,111
		10	SHARED DISPOSITIVE POWER
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	53,368,111
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	33.1%
14	TYPE OF REPORTING PERSON
	OO – limited liability company

CUSIP No. 46122T102 Page 5 of 12

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
	THIRD SECURITY CAPITAL PARTNERS V, LLC I.R.S. IDENTIFICATION NO.: 52-2395642
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF GROUP			(a)	☐
				(b)	☒
3	SEC USE ONLY
4	SOURCE OF FUNDS
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			8,325,000
		8	SHARED VOTING POWER
			0
		9	SOLE DISPOSITIVE POWER
			8,325,000
		10	SHARED DISPOSITIVE POWER
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	8,325,000
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	5.2%
14	TYPE OF REPORTING PERSON
	OO – limited liability company

CUSIP No. 46122T102 Page 6 of 12

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
	NRM VI HOLDINGS I, LLC I.R.S. IDENTIFICATION NO.: 27-1471440
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF GROUP			(a)	☐
				(b)	☒
3	SEC USE ONLY
4	SOURCE OF FUNDS
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Virginia
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			13,340,645
		8	SHARED VOTING POWER
			0
		9	SOLE DISPOSITIVE POWER
			13,340,645
		10	SHARED DISPOSITIVE POWER
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	13,340,645
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	8.3%
14	TYPE OF REPORTING PERSON
	OO – limited liability company

CUSIP No. 46122T102 Page 7 of 12

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
	KAPITAL JOE, LLC I.R.S. IDENTIFICATION NO.: 45-2595931
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF GROUP			(a)	☐
				(b)	☒
3	SEC USE ONLY
4	SOURCE OF FUNDS
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Virginia
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			14,140,139
		8	SHARED VOTING POWER
			0
		9	SOLE DISPOSITIVE POWER
			14,140,139
		10	SHARED DISPOSITIVE POWER
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	14,140,139
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	8.8%
14	TYPE OF REPORTING PERSON
	OO – limited liability company

CUSIP No. 46122T102 Page 8 of 12

This Amendment No. 8 (the “Amendment”) amends and supplements the Statement on Schedule 13D, dated March 27, 2014 and filed on April 7, 2014, as amended by Amendment No. 1 dated December 31, 2014 and filed on January 5, 2015, by Amendment No. 2 dated May 31, 2016 and filed  June 2, 2016, by Amendment No. 3 dated July 24, 2017 and filed July 26, 2017, by Amendment No. 4 dated October 16, 2017 and filed October 23, 2017, by Amendment No. 5 dated December 29, 2017 and filed on January 2, 2018, by Amendment No. 6 dated January 19, 2018 and filed January 22, 2018, and by Amendment No. 7 dated July 3, 2018 and filed July 6, 2018 (the “Original Schedule 13D”), relating to the Common Stock, no par value per share (the “Common Stock”), of Intrexon Corporation, a Virginia corporation (the “Company”).  Mr. Randal J. Kirk (“Mr. Kirk”), the R.J. Kirk Declaration of Trust, a revocable trust established by Mr. Kirk (“RJ DOT”), Third Security, LLC, a Virginia limited liability company that is controlled by Mr. Kirk (“Third Security”), Third Security Capital Partners V, LLC, a Delaware limited liability company that is managed by Third Security (“TSCP V”), Kapital Joe, LLC, a Virginia limited liability company that is managed by Third Security (“Kapital Joe”), and NRM VI Holdings I, LLC, a Delaware limited liability company that is managed by an affiliate that is managed by Third Security (“NRM VI Holdings” and, together with Mr. Kirk, the RJ DOT, Third Security, TSCP V, and Kapital Joe, the “Reporting Persons”) are filing this Amendment to disclose the purchase by entities under the common control of Mr. Kirk of 2,096,209 shares of Common Stock, in open market transactions between May 13, 2019 and May 15, 2019 (the “Purchased Shares”),.

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

Item 3 of the Original Schedule 13D is hereby amended and supplemented as follows:

The following Reporting Persons, entities managed by Third Security, or entities for which a Reporting Person is trustee (hereinafter collectively referred to as the “Purchasing Entities”), each utilized its working capital to purchase 2,096,209 shares, in open market transactions between May 13, 2019 and May 15, 2019, for an aggregate purchase price of approximately $9,216,245.

Entity	Number of Purchased Shares	Percentage of Shares of Common Stock Purchased
RJ DOT	734,219		35.026	%
JPK 2008, LLC	19,956		0.952	%
JPK 2009, LLC	151,472		7.226	%
JPK 2012, LLC	67,373		3.214	%
MGK 2008, LLC	19,159		0.914	%
MGK 2009, LLC	157,509		7.514	%
MGK 2011, LLC	68,379		3.262	%
ZSK 2008, LLC	18,823		0.898	%
ZSK 2009, LLC	14,045		0.670	%
Kellie L. Banks (2009) Long Term Trust	6,792		0.324	%
Third Security Senior Staff 2015 LLC	335,393		16.000	%
Third Security Staff 2015 LLC	335,393		16.000	%
Third Security Incentive 2010 LLC	167,696		8.000	%

CUSIP No. 46122T102 Page 9 of 12

On May 13, 2019, the Purchasing Entities entered into a purchase agreement setting forth the allocation of the Purchased Shares, which allocation is set forth in the table above. Shares purchased pursuant to the purchase agreement were allocated to each purchasing entity at the same price per share.

Item 4. Purpose of Transaction.

Item 4 of the Original Schedule 13D is hereby amended and supplemented as follows:

The information set forth in Items 3 and 6 is incorporated herein by reference.

The shares disclosed herein were acquired by the Purchasing Entities for investment purposes.

Item 5. Interest in Securities of the Issuer.

Items 5(a) and (b) of the Original Schedule 13D are hereby amended and restated to read in their entirety as follows:

(a) and (b)  See items 11 and 13 of the cover pages to this Statement for the aggregate number of shares and percentage of issued and outstanding shares of Common Stock of the Company owned by the Reporting Persons. The percentage ownership is calculated based on 160,764,358 shares of Common Stock issued and outstanding as of April 30, 2019 as disclosed in the Intrexon Corporation Quarterly Report on Form 10-Q for the period ended March 31, 2019 and filed on May 9, 2019, increased by508,617 shares of Common Stock issued to Third Security on May 1, 2019, pursuant to the Services Agreement by and between the Company and Third Security dated November 1, 2015, as amended by the First Amendment to the Services Agreement dated October 31, 2016, as amended by the Second Amendment to the Services Agreement dated December 30, 2016, as amended by the Third Amendment to the Services Agreement dated December 28, 2017, and as amended by the Fourth Amendment to the Services Agreement dated April 18, 2019 (the “Services Agreement”).

CUSIP No. 46122T102 Page 10 of 12

Reporting Person	Amount of Common StockBeneficiallyOwned		Percentof Class			Sole Powerto Vote orDirectthe Vote		SharedPower toVote orDirectthe Vote		Sole Power toDispose or toDirect theDisposition		Shared Power toDispose or toDirect theDisposition
Randal J. Kirk		70,439,882		43.7	%		70,439,882		--		70,439,882		--
R.J. Kirk Declaration of Trust		16,924,973		10.5	%		16,924,973		--		16,924,973
Third Security, LLC		53,368,111		33.1	%		53,368,111		--		53,368,111		--
Third Security Capital Partners V, LLC		8,325,000		5.2	%		8,325,000		--		8,325,000		--
NRM VI Holdings I, LLC		13,340,645		8.3	%		13,340,645		--		13,340,645		--
Kapital Joe, LLC		14,140,139		8.8	%		14,140,139		--		14,140,139		--

Mr. Kirk could be deemed to have indirect beneficial ownership of the shares of Common Stock directly beneficially owned by the RJ DOT, Third Security, TSCP V, Kapital Joe, and NRM VI Holdings.  Mr. Kirk controls Third Security, which is the manager of TSCP V and Kapital Joe and which manages the manager of NRM VI Holdings.

(c)          Pursuant to the Services Agreement, the Company has agreed to pay to Third Security, on a monthly basis, such number of shares of Common Stock, rounded down to the nearest whole number, equal to a value of $800,000.  The number of shares issuable to Third Security shall be calculated by dividing $800,000 by the volume-weighted average of the price of the Common Stock (as calculated by Bloomberg) over the 30-day period ending on the 15^th day of the calendar month during which the applicable services are provided.  The Services Agreement may be terminated by the Company at any time and, unless earlier terminated, will continue until January 1, 2020.  Pursuant to the Services Agreement, on May 1, 2019, the Company issued 508,617 shares of Common Stock to Third Security as consideration for the services provided from January 1, 2019 through April 30, 2019.  Such number of shares was calculated on a per month basis using the applicable volume-weighted average of the price: (i) 111,225 shares at price of $7.19 per share for the month of January 2019; (ii) 99,328 shares at a price of $8.05 per share for the month of February 2019; (iii) 146,161 shares at a price of $5.47 per share for the month of March 2019; and (iv) 151,903 shares at a price of $5.27 per share for the month of April 2019.

Pursuant to the Restricted Stock Unit Agreement by and between the Company and Randal J. Kirk dated November 1, 2015 (the “RSU Agreement”), the Company agreed to pay to Mr. Kirk, on a monthly basis, that number of shares of Common Stock, rounded down to the nearest whole share, whose fair market value equals $200,000.  The number of shares of Common Stock are to become vested and payable based upon the closing price of the Common Stock on the NYSE on the last calendar day of each month (or, if such date is not a trading day, the most recent trading day prior to such date).  The term of the RSU Agreement expired on March 31, 2019.  Pursuant to the RSU Agreement, the Company issued to Mr. Kirk 38,022 shares of Common Stock on March 29, 2019.

CUSIP No. 46122T102 Page 11 of 12

Following the expiration of the RSU Agreement, the Company and Randal J. Kirk entered into a Restricted Stock Unit Agreement on April 1, 2019 (the “2019 RSU Agreement”), pursuant to which the Company has agreed to pay to Mr. Kirk, on a monthly basis, that number of shares of Common Stock, rounded down to the nearest whole share, whose fair market value equals $200,000.  The number of shares of Common Stock are to become vested and payable based upon the volume-weighted average of the price of the Common Stock (as calculated by Bloomberg) over the 30-day period ending on the last calendar day of the month.  Unless earlier terminated pursuant to the provisions of the Company’s Amended and Restated 2013 Omnibus Incentive Plan, the 2019 RSU Agreement will expire on March 31, 2020.  Mr. Kirk has designated the RJ DOT to receive shares awarded to him pursuant to the 2019 RSU Agreement.  Pursuant to the 2019 RSU Agreement, the Company issued to Mr. Kirk 43,887 shares of Common Stock on April 30, 2019.

Except as disclosed herein, none of the Reporting Persons have engaged in any transactions in the Company’s Common Stock in the past 60 days.

(d) – (e)    Not applicable

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

Item 6 of the Original Schedule 13D is hereby amended and restated to read in its entirety as follows:

The Reporting Persons’ response to Item 3 is incorporated herein by reference.

Item 7. Material to be Filed as Exhibits.

Exhibit 1 Joint Filing Agreement, dated as of May 15, 2019, by and among Randal J. Kirk, the R.J. Kirk Declaration of Trust, Third Security, LLC, Third Security Capital Partners V, LLC, Kapital Joe, LLC, and NRM VI Holdings I, LLC.

CUSIP No. 46122T102 Page 12 of 12

SIGNATURES

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

Date: May 15, 2019
	/s/ Randal J. Kirk
	Randal J. Kirk
	R.J. KIRK DECLARATION OF TRUST
	By:	/s/ Randal J. Kirk
		Randal J. Kirk
		Trustee
	THIRD SECURITY, LLC
	By:	/s/ Randal J. Kirk
		Randal J. Kirk
		Manager
	THIRD SECURITY CAPITAL PARTNERS V, LLC
	By:	/s/ Randal J. Kirk
		Randal J. Kirk
		Manager
	KAPITAL JOE, LLC
	By:	/s/ Randal J. Kirk
		Randal J. Kirk
		Manager
	NRM VI HOLDINGS I, LLC
	By:	/s/ Randal J. Kirk
		Randal J. Kirk
		Manager

EXHIBIT INDEX

Exhibit 1 Joint Filing Agreement, dated as of May 15, 2019, by and among Randal J. Kirk, the R.J. Kirk Declaration of Trust, Third Security, LLC, Third Security Capital Partners V, LLC, Kapital Joe, LLC, and NRM VI Holdings I, LLC.