13G Filing: Boxer Capital, LLC and Macrogenics Inc (MGNX)

---

Item 1(a). Name of Issuer:

Macrogenics, Inc. (the Issuer)

Item 1(b). Address of Issuers Principal Executive Offices:

9704 Medical Center Drive

Rockville, MD 20850

Item 2(a). Name of
Person Filing:

This Schedule 13G is jointly filed by Boxer Capital, LLC (Boxer Capital), Boxer Asset Management Inc.
(Boxer Management) and Joe Lewis (together with Boxer Capital and Boxer Management, the Reporting Persons). Boxer Management is the managing member and majority owner of Boxer Capital. Joe Lewis is the sole indirect
beneficial owner of and controls Boxer Management.

Item 2(b). Address of Principal Business Office, or, if none, Residence:

The principal business address of Boxer Capital is: 11682 El Camino Real, Suite 320, San Diego, CA 92130. The principal business address of
Boxer Management and Joe Lewis is: Cay House, EP Taylor Drive N7776, Lyford Cay, New Providence, Bahamas.

Item 2(c). Citizenship:

Boxer Capital is a limited liability company organized under the laws of Delaware. Boxer Management is a corporation organized under the laws
of the Bahamas. Joe Lewis is a citizen of the United Kingdom.

Item 2(d). Title of Class of Securities:

Common Stock, par value $0.01 per share (the Common Stock).

Item 2(e). CUSIP Number:

556099109

Item 3. If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b) or (c), check whether the person filing is a:

Not applicable.

Item 4. Ownership.

(a)

Amount beneficially owned:

The Reporting Persons beneficially own 1,987,000 shares of Common
Stock.

(b)

Percent of class:

The shares of Common Stock beneficially owned by the Reporting Persons
represents 5.5%* of the Issuers outstanding shares of Common Stock.

(c)

Number of shares as to which such person has:

(i)

Sole power to vote or direct the vote:

None of the Reporting Persons has the sole power to
vote or to direct the vote of any shares of Common Stock the Reporting Persons beneficially own.