UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G/A

Under the Securities Exchange Act of 1934

(Amendment No. 2)

Nightstar Therapeutics plc

(Name of Issuer)

Ordinary Shares, nominal value £0.01

(Title of Class of Securities)

65413A101

(CUSIP Number)

December 31, 2019

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

þ Rule 13d-1(b)

¨ Rule 13d-1(c)

¨ Rule 13d-1(d)

* 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 the disclosures provided in a prior cover page.

The information required in 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. 65413A101

1	Name of Reporting Person Redmile Group, LLC
2	Check the Appropriate Box if a Member of a Group (See Instructions) (a) ¨ (b) ¨
3	SEC Use Only
4	Citizenship or Place of Organization Delaware

number of
shares
beneficially
owned by
each
reporting
person with

Sole Voting Power

Shared Voting Power

Sole Dispositive Power

Shared Dispositive Power

9	Aggregate Amount Beneficially Owned by Each Reporting Person 0
10	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)
11	Percent of Class Represented by Amount in Row (9) 0%
12	Type of Reporting Person (See Instructions) IA, OO

CUSIP No. 65413A101

1	Name of Reporting Person Jeremy C. Green
2	Check the Appropriate Box if a Member of a Group (See Instructions) (a) ¨ (b) ¨
3	SEC Use Only
4	Citizenship or Place of Organization United Kingdom

number of
shares
beneficially
owned by
each
reporting
person with

Sole Voting Power

Shared Voting Power

Sole Dispositive Power

Shared Dispositive Power

9	Aggregate Amount Beneficially Owned by Each Reporting Person 0
10	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)
11	Percent of Class Represented by Amount in Row (9) 0%
12	Type of Reporting Person (See Instructions) IN, HC

Item 1.

(a) Name of Issuer

Nightstar Therapeutics plc

(b) Address of Issuer’s Principal Executive Offices

10 Midford Place, 2nd Floor

London W1T 5BJ United Kingdom

Item 2.

(a) Names of Persons Filing

Redmile Group, LLC

Jeremy C. Green

(b) Address of Principal Business office or, if None, Residence

Redmile Group, LLC

One Letterman Drive

Building D, Suite D3-300

The Presidio of San Francisco

San Francisco, California 94129

Jeremy C. Green

c/o Redmile Group, LLC

One Letterman Drive

Building D, Suite D3-300

The Presidio of San Francisco

San Francisco, California 94129

Redmile Group, LLC: Delaware
Jeremy C. Green: United Kingdom

(d) Title of Class of Securities

Ordinary Shares, nominal value £0.01

(e) CUSIP Number

65413A101

Item 3.

If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

(a)

¨ Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);

(b)

¨ Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);

(c)

¨ Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);

(d)

¨ Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C 80a-8);

(e)

x An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

(f)

¨ An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

(g)

¨ A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

(h)

¨ A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

¨ A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

¨ A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J);

(k)

¨ Group, in accordance with § 240.13d-1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution: __________

Item 4.

Ownership.

(a)

Amount beneficially owned:

Redmile Group, LLC – 0
Jeremy C. Green – 0

(b)

Percent of class:

Redmile Group, LLC – 0%
Jeremy C. Green – 0%

(c)

Number of shares as to which Redmile Group, LLC has:

(i)

Sole power to vote or to direct the vote:

(ii)

Shared power to vote or to direct the vote:

(iii)

Sole power to dispose or to direct the disposition of:

(iv)

Shared power to dispose or to direct the disposition of:

Number of shares as to which Jeremy C. Green has:

(i)

Sole power to vote or to direct the vote:

(ii)

Shared power to vote or to direct the vote:

(iii)

Sole power to dispose or to direct the disposition of:

(iv)

Shared power to dispose or to direct the disposition of:

Item 5.

Ownership of Five Percent or Less of a Class.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than 5 percent of the class of securities, check the following x

Item 6.

Ownership of More than Five Percent on Behalf of Another Person.

N/A.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person.

See Exhibit A attached hereto.

Item 8.

Identification and Classification of Members of the Group.

N/A

Item 9.

Notice of Dissolution of Group.

N/A

Item 10.

Certifications.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

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: February 14, 2020

	Redmile Group, LLC

	By:		/s/ Jeremy C. Green
			Name: Jeremy C. Green Title: Managing Member

/s/ Jeremy C. Green

Jeremy C. Green

Exhibit A

Redmile Group, LLC is the relevant entity for which Jeremy C. Green may be considered a control person.

Nightstar Therapeutics plc SC 13G/A