Sec Form 4 Filing - Pontifax Management 4 G.P. (2015) Ltd. @ Eloxx Pharmaceuticals, Inc. - 2019-06-24

FORM 4 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. [ ELOX] 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 3. Date of Earliest Transaction (MM/DD/YY) 06/24/2019 (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 06/24/2019 P( 1 ) 42,261 A $ 9 ( 1 ) 510,846 I By Pontifax Investment Fund ( 2 ) Common Stock 06/24/2019 P( 1 ) 86,806 A $ 9 ( 1 ) 1,049,310 I By Pontifax Investment Fund ( 3 ) Common Stock 06/24/2019 P( 1 ) 46,933 A $ 9 ( 1 ) 567,329 I By Pontifax Investment Fund ( 4 ) Common Stock 06/24/2019 P( 1 ) 24,000 A $ 9 ( 1 ) 24,000 I By Pontifax Investment Fund ( 5 )

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 WALTHAM, MA02451 X Pontifax (China) IV L.P. C/O ELOXX PHARMACEUTICALS, INC. 950 WINTER STREET WALTHAM, MA02451 X Pontifax (Cayman) IV L.P. C/O ELOXX PHARMACEUTICALS, INC. 950 WINTER STREET WALTHAM, MA02451 X Pontifax (Israel) IV, L.P. C/O ELOXX PHARMACEUTICALS, INC. 950 WINTER STREET WALTHAM, MA02451 X Pontifax IV GP L.P. C/O ELOXX PHARMACEUTICALS, INC. 950 WINTER STREET WALTHAM, MA02451 X Signatures Pontifax Management 4 G.P. (2015) Ltd. /s/ Neil Belloff, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 06/26/2019 Signature of Reporting Person Date Pontifax (China) IV L.P. /s/ Neil Belloff, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 06/26/2019 Signature of Reporting Person Date Pontifax (Cayman) IV L.P. /s/ Neil Belloff, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 06/26/2019 Signature of Reporting Person Date Pontifax (Israel) IV, L.P. /s/ Neil Belloff, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 06/26/2019 Signature of Reporting Person Date Pontifax IV GP L.P. /s/ Neil Belloff, Attorney in Fact on behalf of Tomer Kariv, Chief Executive Officer 06/26/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Reflects the purchase of shares in the offering of Common Stock of Eloxx Pharmaceuticals, Inc. that closed on June 24, 2019. ( 2 )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. ( 3 )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. ( 4 )Represents shares of the Issuer held by Pontifax (China) IV L.P. ("China IV"). Pontifax IV 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. ( 5 )Represents shares of the Issuer held by Pontifax Late Stage Fund L.P.("Late Stage Fund"). Pontifax Late Stage GP Ltd. ("Late Stage GP"), the general partner of Late Stage Fund, has a Strategic Alliance Agreement with Pontifax IV. By virtue of this relationship, Pontifax IV may be deemed to share voting and dispositive power with respect to the shares held by Late Stage Fund. Each of Management 4, Pontifax IV, Late Stage Fund and Late Stage GP 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.

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