Sec Form 3 Filing - Pontifax Management 4 G.P. (2015) Ltd. @ Eloxx Pharmaceuticals, Inc. - 2017-12-19

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Pontifax Management 4 G.P. (2015) Ltd. 2. Issuer Name and Ticker or Trading Symbol Eloxx Pharmaceuticals, Inc. [ SVOND] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O ELOXX PHARMACEUTICALS, INC., 950 WINTER STREET, 4TH FLOOR NORTH 3. Date of Earliest Transaction (MM/DD/YY) 12/19/2017 (Street) WALTHAM, MA02451 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 381,518 I By Pontifax Investment Fund ( 1 ) Common Stock 783,664 I By Pontifax Investment Fund ( 2 ) Common Stock 423,703 I By Pontifax Investment Fund ( 3 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Pontifax Management 4 G.P. (2015) Ltd. C/O ELOXX PHARMACEUTICALS, INC. 950 WINTER STREET, 4TH FLOOR NORTH WALTHAM, MA02451 X Pontifax IV GP L.P. C/O ELOXX PHARMACEUTICALS, INC. 950 WINTER STREET, 4TH FLOOR NORTH WALTHAM, MA02451 X Pontifax (Cayman) IV L.P. C/O ELOXX PHARMACEUTICALS, INC. 950 WINTER STREET, 4TH FLOOR NORTH WALTHAM, MA02451 X Pontifax (Israel) IV, L.P. C/O ELOXX PHARMACEUTICALS, INC. 950 WINTER STREET, 4TH FLOOR NORTH WALTHAM, MA02451 X Pontifax (China) IV L.P. C/O ELOXX PHARMACEUTICALS, INC. 950 WINTER STREET, 4TH FLOOR NORTH WALTHAM, MA02451 X Signatures Pontifax Management 4 G.P. (2015) Ltd. /s/ Gregory Weaver, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 12/29/2017 Signature of Reporting Person Date Pontifax IV GP L.P. /s/ Gregory Weaver, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 12/29/2017 Signature of Reporting Person Date Pontifax (Cayman) IV L.P. /s/ Gregory Weaver, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 12/29/2017 Signature of Reporting Person Date Pontifax (Israel) IV, L.P. /s/ Gregory Weaver, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 12/29/2017 Signature of Reporting Person Date Pontifax (China) IV L.P. /s/ Gregory Weaver, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 12/29/2017 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents shares of the Issuer held by Pontifax (Cayman) IV L.P. ("Cayman IV"). Pontifax IV GP L.P. ("Pontifax IV") is the general partner of Cayman IV. Pontifax Management 4 G.P. (2015) Ltd. ("Management 4") is the general partner of Pontifax IV. As a result, each of Management 4 and Pontifax IV may be deemed to share voting and dispositive power with respect to the shares held by Cayman IV. Each of Management 4, Pontifax IV and Cayman IV disclaims beneficial ownership of such shares, except to the extent of its pecuniary interest therein, and the inclusion of the shares in this report shall not be deemed to be an admission of beneficial ownership of the reported shares for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise. ( 2 )Represents shares of the Issuer held by Pontifax (Israel) IV, L.P. ("Israel IV"). Pontifax IV is the general partner of Israel IV. Management 4 is the general partner of Pontifax IV. As a result, each of Management 4 and Pontifax IV may be deemed to share voting and dispositive power with respect to the shares held by Israel IV. Each of Management 4, Pontifax IV and Israel IV disclaims beneficial ownership of such shares, except to the extent of its pecuniary interest therein, and the inclusion of the shares in this report shall not be deemed to be an admission of beneficial ownership of the reported shares for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise. ( 3 )Represents shares of the Issuer held by Pontifax (China) IV L.P. ("China IV"). Pontifax IV GP L.P. is the general partner of China IV. Management 4 is the general partner of Pontifax IV. As a result, each of Management 4 and Pontifax IV may be deemed to share voting and dispositive power with respect to the shares held by China IV. Each of Management 4, Pontifax IV and China IV disclaims beneficial ownership of such shares, except to the extent of its pecuniary interest therein, and the inclusion of the shares in this report shall not be deemed to be an admission of beneficial ownership of the reported shares for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise.

Remarks: Exhibit 24.1 - Pontifax Management 4 G.P. (2015) Ltd. Power of Attorney. Exhibit 24.2 - Pontifax IV GP L.P. Power of Attorney. Exhibit 24.3 - Pontifax (Cayman) IV L.P. Power of Attorney. Exhibit 24.4 - Pontifax (Israel) IV, L.P. Power of Attorney Exhibit. 24.5 - Pontifax (China) IV L.P. Power of Attorney.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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