SEC Filing - Keros Therapeutics

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SEC FORM 3 SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
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.

(Last)

(First)

(Middle)

14 SHENKAR STREET, BEIT OFEK

(Street)

HERZLIYA PITUACH

46140

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
04/07/2020

3. Issuer Name and Ticker or Trading Symbol
Keros Therapeutics, Inc. [ KROS ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

Director	X	10% Owner
Officer (give title below)		Other (specify below)

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	370,853	I	See footnote⁽¹⁾
Common Stock	180,546	I	See footnote⁽²⁾
Common Stock	200,509	I	See footnote⁽³⁾

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Series A Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	1,363,542	⁽⁴⁾	I	See footnote⁽¹⁾
Series A Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	663,825	⁽⁴⁾	I	See footnote⁽²⁾
Series A Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	737,226	⁽⁴⁾	I	See footnote⁽³⁾
Series B-1 Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	169,307	⁽⁴⁾	I	See footnote⁽¹⁾
Series B-1 Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	82,425	⁽⁴⁾	I	See footnote⁽²⁾
Series B-1 Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	91,538	⁽⁴⁾	I	See footnote⁽³⁾
Series B-1 Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	68,654	⁽⁴⁾	I	See footnote⁽⁵⁾⁽⁶⁾
Series C Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	163,612	⁽⁴⁾	I	See footnote⁽¹⁾
Series C Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	88,460	⁽⁴⁾	I	See footnote⁽²⁾
Series C Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	79,653	⁽⁴⁾	I	See footnote⁽³⁾
Series C Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	36,858	⁽⁴⁾	I	See footnote⁽⁵⁾⁽⁶⁾

1. Name and Address of Reporting Person^*

Pontifax Management 4 G.P. (2015) Ltd.

(Last)

(First)

(Middle)

14 SHENKAR STREET, BEIT OFEK

(Street)

HERZLIYA PITUACH

46140

(City)

(State)

(Zip)

1. Name and Address of Reporting Person^*

Pontifax (Israel) IV, L.P.

(Last)

(First)

(Middle)

14 SHENKAR STREET, BEIT OFEK

(Street)

HERZLIYA PITUACH

46140

(City)

(State)

(Zip)

1. Name and Address of Reporting Person^*

Pontifax (Cayman) IV L.P.

(Last)

(First)

(Middle)

14 SHENKAR STREET, BEIT OFEK

(Street)

HERZLIYA PITUACH

46140

(City)

(State)

(Zip)

1. Name and Address of Reporting Person^*

Pontifax (China) IV L.P.

(Last)

(First)

(Middle)

14 SHENKAR STREET, BEIT OFEK

(Street)

HERZLIYA PITUACH

46140

(City)

(State)

(Zip)

1. Name and Address of Reporting Person^*

Pontifax Late Stage Fund L.P.

(Last)

(First)

(Middle)

14 SHENKAR STREET, BEIT OFEK

(Street)

HERZLIYA PITUACH

(City)

(State)

(Zip)

1. Name and Address of Reporting Person^*

Pontifax Late Stage GP Ltd.

(Last)

(First)

(Middle)

14 SHENKAR STREET, BEIT OFEK

(Street)

HERZLIYA PITUACH

46140

(City)

(State)

(Zip)

Explanation of Responses:

1. The securities are held by Pontifax (Israel) IV, L.P. ("Israel IV"). Pontifax Management 4 G.P. (2015) Ltd. ("Management 4") is the ultimate general partner of Israel IV. As a result Management 4 may be deemed to share voting and dispositive power with respect to the shares held by Israel IV. Management 4 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. The securities are held by Pontifax (Cayman) IV, L.P. ("Cayman IV"). Management 4 is the ultimate general partner of Cayman IV. As a result Management 4 may be deemed to share voting and dispositive power with respect to the shares held by Cayman IV. Management 4 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. The securities are held by Pontifax (China) IV, L.P. ("China IV"). Management 4 is the ultimate general partner of China IV. As a result Management 4 may be deemed to share voting and dispositive power with respect to the shares held by China IV. Management 4 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. Each share of Series A Preferred Stock, Series B-1 Preferred Stock and Series C Preferred Stock is convertible at any time, at the holder's election, into Common Stock, on a one-for-one basis, has no expiration date and will convert into shares of Common Stock upon the closing of the Issuer's initial public offering.

5. The securities are held by Pontifax Late Stage Fund, L.P. ("Late Stage"). Pontifax Late Stage GP Ltd. ("Late Stage GP") is the general partner of Late Stage and the sole shareholder of Late Stage GP is Mr. Shlomo Karako. Pursuant to Strategic Alliance Agreement, dated August 9, 2018, between Late Stage, Israel IV, Cayman IV and China IV (collectively the, "Pontifax IV Funds"), Late Stage invests side-by-side with the Pontifax IV Funds. By virtue of the strategic relationship, Management 4 may be deemed to share voting and dispositive power with respect to the shares held by Late Stage in a manner similar to the voting and investment power with respect to the shares held by each of the Pontifax IV Funds.

6. Each of Management 4 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.

Remarks:

Exhibit List - Exhibit 24 - Power of Attorney Exhibit 24.1 - Power of Attorney Exhibit 24.2 - Power of Attorney Exhibit 24.3 - Power of Attorney Exhibit 24.4 - Power of Attorney Exhibit 24.5 - Power of Attorney

	/s/ Keith Regnante, Attorney-in-Fact for Pontifax Management 4 G.P. (2015) Ltd.	04/07/2020
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax (Israel) IV L.P.	04/07/2020
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax (Cayman) IV L.P.	04/07/2020
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax (China) IV L.P.	04/07/2020
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax Late Stage Fund, L.P.	04/07/2020
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax Late Stage GP Ltd.	04/07/2020
	** Signature of Reporting Person	Date
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 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

Exhibit 24

POWER OF ATTORNEY

(For Executing Form ID and Forms 3, 4 and 5)

	Know all by these presents, that the undersigned hereby constitutes and
appoints each of Ryan Sansom, Esther Cho, Trey Reilly and Jason Minio of Cooley
LLP, and Jasbir Seehra and Keith Regnante of Keros Therapeutics, Inc. (the
"Company"), signing individually, the undersigned's true and lawful attorneys-in
fact and agents to:

	(1)	Prepare, execute in the undersigned's name and on the undersigned's behalf,
and submit to the Securities and Exchange Commission (the "SEC"), a Form ID and
Forms 3, 4 and 5 (including amendments thereto and joint filing agreements in
connection therewith) in accordance with Section 16 of the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), and the rules thereunder, in the
undersigned's capacity as an officer, director or beneficial owner of more than
10% of a registered class of securities of the Company;

	(2)	Do and perform any and all acts for and on behalf of the undersigned that
may be necessary or desirable to prepare and execute any such Form ID and Forms
3, 4 or 5 (including amendments thereto and joint filing agreements in
connection therewith) and file such forms with the SEC and any stock exchange,
self-regulatory association or any similar authority; and

	(3)	Take any other action of any type whatsoever in connection with the
foregoing that, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required of the undersigned, it being
understood that the documents executed by the attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as the attorney-in-fact may approve in the
attorney-in-fact's discretion.

	The undersigned hereby grants to each such attorney in fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney in fact, or such attorney
in fact's substitute or substitutes, shall lawfully do or cause to be done by
virtue of this power of attorney and the rights and powers herein granted.  The
undersigned acknowledges that the foregoing attorneys-in-fact, and their
substitutes, in serving in such capacity at the request of the undersigned, are
not assuming (nor is the Company assuming) any of the undersigned's
responsibilities to comply with Section 16 of the Exchange Act.

	This Power of Attorney shall remain in full force and effect until the earliest
to occur of (a) the undersigned is no longer required to file Forms 3, 4 and 5
with respect to the undersigned's holdings of and transactions in securities
issued by the Company, (b) revocation by the undersigned in a signed writing
delivered to the Company and the foregoing attorneys-in fact or (c) as to any
attorney-in-fact individually, until such attorney-in-fact is no longer employed
by the Company or employed by or a partner at Cooley LLP or another law firm
representing the Company, as applicable.

	IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of the date written below.

Date:  April 1, 2020
Pontifax Management 4 G.P. (2015) Ltd.
By: /s/ Tomer Kariv
Name: Tomer Kariv
Title: CEO

Exhibit 24.1

POWER OF ATTORNEY

(For Executing Form ID and Forms 3, 4 and 5)

	Know all by these presents, that the undersigned hereby constitutes and
appoints each of Ryan Sansom, Esther Cho, Trey Reilly and Jason Minio of Cooley
LLP, and Jasbir Seehra and Keith Regnante of Keros Therapeutics, Inc. (the
"Company"), signing individually, the undersigned's true and lawful attorneys-in
fact and agents to:

	(1)	Prepare, execute in the undersigned's name and on the undersigned's behalf,
and submit to the Securities and Exchange Commission (the "SEC"), a Form ID and
Forms 3, 4 and 5 (including amendments thereto and joint filing agreements in
connection therewith) in accordance with Section 16 of the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), and the rules thereunder, in the
undersigned's capacity as an officer, director or beneficial owner of more than
10% of a registered class of securities of the Company;

	(2)	Do and perform any and all acts for and on behalf of the undersigned that
may be necessary or desirable to prepare and execute any such Form ID and Forms
3, 4 or 5 (including amendments thereto and joint filing agreements in
connection therewith) and file such forms with the SEC and any stock exchange,
self-regulatory association or any similar authority; and

	(3)	Take any other action of any type whatsoever in connection with the
foregoing that, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required of the undersigned, it being
understood that the documents executed by the attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as the attorney-in-fact may approve in the
attorney-in-fact's discretion.

	The undersigned hereby grants to each such attorney in fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney in fact, or such attorney
in fact's substitute or substitutes, shall lawfully do or cause to be done by
virtue of this power of attorney and the rights and powers herein granted.  The
undersigned acknowledges that the foregoing attorneys-in-fact, and their
substitutes, in serving in such capacity at the request of the undersigned, are
not assuming (nor is the Company assuming) any of the undersigned's
responsibilities to comply with Section 16 of the Exchange Act.

	This Power of Attorney shall remain in full force and effect until the earliest
to occur of (a) the undersigned is no longer required to file Forms 3, 4 and 5
with respect to the undersigned's holdings of and transactions in securities
issued by the Company, (b) revocation by the undersigned in a signed writing
delivered to the Company and the foregoing attorneys-in fact or (c) as to any
attorney-in-fact individually, until such attorney-in-fact is no longer employed
by the Company or employed by or a partner at Cooley LLP or another law firm
representing the Company, as applicable.

	IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of the date written below.

Date: April 1, 2020
Pontifax (Israel) IV L.P.
By: /s/ Asaf Shinar
Name: Asaf Shinar
Title: CFO

Exhibit 24.2

POWER OF ATTORNEY

(For Executing Form ID and Forms 3, 4 and 5)

	Know all by these presents, that the undersigned hereby constitutes and
appoints each of Ryan Sansom, Esther Cho, Trey Reilly and Jason Minio of Cooley
LLP, and Jasbir Seehra and Keith Regnante of Keros Therapeutics, Inc. (the
"Company"), signing individually, the undersigned's true and lawful attorneys-in
fact and agents to:

	(1)	Prepare, execute in the undersigned's name and on the undersigned's behalf,
and submit to the Securities and Exchange Commission (the "SEC"), a Form ID and
Forms 3, 4 and 5 (including amendments thereto and joint filing agreements in
connection therewith) in accordance with Section 16 of the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), and the rules thereunder, in the
undersigned's capacity as an officer, director or beneficial owner of more than
10% of a registered class of securities of the Company;

	(2)	Do and perform any and all acts for and on behalf of the undersigned that
may be necessary or desirable to prepare and execute any such Form ID and Forms
3, 4 or 5 (including amendments thereto and joint filing agreements in
connection therewith) and file such forms with the SEC and any stock exchange,
self-regulatory association or any similar authority; and

	(3)	Take any other action of any type whatsoever in connection with the
foregoing that, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required of the undersigned, it being
understood that the documents executed by the attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as the attorney-in-fact may approve in the
attorney-in-fact's discretion.

	The undersigned hereby grants to each such attorney in fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney in fact, or such attorney
in fact's substitute or substitutes, shall lawfully do or cause to be done by
virtue of this power of attorney and the rights and powers herein granted.  The
undersigned acknowledges that the foregoing attorneys-in-fact, and their
substitutes, in serving in such capacity at the request of the undersigned, are
not assuming (nor is the Company assuming) any of the undersigned's
responsibilities to comply with Section 16 of the Exchange Act.

	This Power of Attorney shall remain in full force and effect until the earliest
to occur of (a) the undersigned is no longer required to file Forms 3, 4 and 5
with respect to the undersigned's holdings of and transactions in securities
issued by the Company, (b) revocation by the undersigned in a signed writing
delivered to the Company and the foregoing attorneys-in fact or (c) as to any
attorney-in-fact individually, until such attorney-in-fact is no longer employed
by the Company or employed by or a partner at Cooley LLP or another law firm
representing the Company, as applicable.

	IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of the date written below.

Date: April 1, 2020
Pontifax (Cayman) IV L.P.
By: /s/ Tomer Kariv
Name: Tomer Kariv
Title: CEO

Exhibit 24.3

POWER OF ATTORNEY

(For Executing Form ID and Forms 3, 4 and 5)

	Know all by these presents, that the undersigned hereby constitutes and
appoints each of Ryan Sansom, Esther Cho, Trey Reilly and Jason Minio of Cooley
LLP, and Jasbir Seehra and Keith Regnante of Keros Therapeutics, Inc. (the
"Company"), signing individually, the undersigned's true and lawful attorneys-in
fact and agents to:

	(1)	Prepare, execute in the undersigned's name and on the undersigned's behalf,
and submit to the Securities and Exchange Commission (the "SEC"), a Form ID and
Forms 3, 4 and 5 (including amendments thereto and joint filing agreements in
connection therewith) in accordance with Section 16 of the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), and the rules thereunder, in the
undersigned's capacity as an officer, director or beneficial owner of more than
10% of a registered class of securities of the Company;

	(2)	Do and perform any and all acts for and on behalf of the undersigned that
may be necessary or desirable to prepare and execute any such Form ID and Forms
3, 4 or 5 (including amendments thereto and joint filing agreements in
connection therewith) and file such forms with the SEC and any stock exchange,
self-regulatory association or any similar authority; and

	(3)	Take any other action of any type whatsoever in connection with the
foregoing that, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required of the undersigned, it being
understood that the documents executed by the attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as the attorney-in-fact may approve in the
attorney-in-fact's discretion.

	The undersigned hereby grants to each such attorney in fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney in fact, or such attorney
in fact's substitute or substitutes, shall lawfully do or cause to be done by
virtue of this power of attorney and the rights and powers herein granted.  The
undersigned acknowledges that the foregoing attorneys-in-fact, and their
substitutes, in serving in such capacity at the request of the undersigned, are
not assuming (nor is the Company assuming) any of the undersigned's
responsibilities to comply with Section 16 of the Exchange Act.

	This Power of Attorney shall remain in full force and effect until the earliest
to occur of (a) the undersigned is no longer required to file Forms 3, 4 and 5
with respect to the undersigned's holdings of and transactions in securities
issued by the Company, (b) revocation by the undersigned in a signed writing
delivered to the Company and the foregoing attorneys-in fact or (c) as to any
attorney-in-fact individually, until such attorney-in-fact is no longer employed
by the Company or employed by or a partner at Cooley LLP or another law firm
representing the Company, as applicable.

	IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of the date written below.

Date: April 1, 2020
Pontifax (China) IV L.P.
By: /s/ Tomer Kariv
Name: Tomer Kariv
Title: CFO

Exhibit 24.4

POWER OF ATTORNEY

(For Executing Form ID and Forms 3, 4 and 5)

	Know all by these presents, that the undersigned hereby constitutes and
appoints each of Ryan Sansom, Esther Cho, Trey Reilly and Jason Minio of Cooley
LLP, and Jasbir Seehra and Keith Regnante of Keros Therapeutics, Inc. (the
"Company"), signing individually, the undersigned's true and lawful attorneys-in
fact and agents to:

	(1)	Prepare, execute in the undersigned's name and on the undersigned's behalf,
and submit to the Securities and Exchange Commission (the "SEC"), a Form ID and
Forms 3, 4 and 5 (including amendments thereto and joint filing agreements in
connection therewith) in accordance with Section 16 of the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), and the rules thereunder, in the
undersigned's capacity as an officer, director or beneficial owner of more than
10% of a registered class of securities of the Company;

	(2)	Do and perform any and all acts for and on behalf of the undersigned that
may be necessary or desirable to prepare and execute any such Form ID and Forms
3, 4 or 5 (including amendments thereto and joint filing agreements in
connection therewith) and file such forms with the SEC and any stock exchange,
self-regulatory association or any similar authority; and

	(3)	Take any other action of any type whatsoever in connection with the
foregoing that, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required of the undersigned, it being
understood that the documents executed by the attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as the attorney-in-fact may approve in the
attorney-in-fact's discretion.

	The undersigned hereby grants to each such attorney in fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney in fact, or such attorney
in fact's substitute or substitutes, shall lawfully do or cause to be done by
virtue of this power of attorney and the rights and powers herein granted.  The
undersigned acknowledges that the foregoing attorneys-in-fact, and their
substitutes, in serving in such capacity at the request of the undersigned, are
not assuming (nor is the Company assuming) any of the undersigned's
responsibilities to comply with Section 16 of the Exchange Act.

	This Power of Attorney shall remain in full force and effect until the earliest
to occur of (a) the undersigned is no longer required to file Forms 3, 4 and 5
with respect to the undersigned's holdings of and transactions in securities
issued by the Company, (b) revocation by the undersigned in a signed writing
delivered to the Company and the foregoing attorneys-in fact or (c) as to any
attorney-in-fact individually, until such attorney-in-fact is no longer employed
by the Company or employed by or a partner at Cooley LLP or another law firm
representing the Company, as applicable.

	IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of the date written below.

Date: April 1, 2020
Pontifax Late Stage Fund, L.P.
By: /s/ Asaf Shinar
Name: Asaf Shinar
Title: CFO

Exhbit 24.5

POWER OF ATTORNEY

(For Executing Form ID and Forms 3, 4 and 5)

	Know all by these presents, that the undersigned hereby constitutes and
appoints each of Ryan Sansom, Esther Cho, Trey Reilly and Jason Minio of Cooley
LLP, and Jasbir Seehra and Keith Regnante of Keros Therapeutics, Inc. (the
"Company"), signing individually, the undersigned's true and lawful attorneys-in
fact and agents to:

	(1)	Prepare, execute in the undersigned's name and on the undersigned's behalf,
and submit to the Securities and Exchange Commission (the "SEC"), a Form ID and
Forms 3, 4 and 5 (including amendments thereto and joint filing agreements in
connection therewith) in accordance with Section 16 of the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), and the rules thereunder, in the
undersigned's capacity as an officer, director or beneficial owner of more than
10% of a registered class of securities of the Company;

	(2)	Do and perform any and all acts for and on behalf of the undersigned that
may be necessary or desirable to prepare and execute any such Form ID and Forms
3, 4 or 5 (including amendments thereto and joint filing agreements in
connection therewith) and file such forms with the SEC and any stock exchange,
self-regulatory association or any similar authority; and

	(3)	Take any other action of any type whatsoever in connection with the
foregoing that, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required of the undersigned, it being
understood that the documents executed by the attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as the attorney-in-fact may approve in the
attorney-in-fact's discretion.

	The undersigned hereby grants to each such attorney in fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney in fact, or such attorney
in fact's substitute or substitutes, shall lawfully do or cause to be done by
virtue of this power of attorney and the rights and powers herein granted.  The
undersigned acknowledges that the foregoing attorneys-in-fact, and their
substitutes, in serving in such capacity at the request of the undersigned, are
not assuming (nor is the Company assuming) any of the undersigned's
responsibilities to comply with Section 16 of the Exchange Act.

	This Power of Attorney shall remain in full force and effect until the earliest
to occur of (a) the undersigned is no longer required to file Forms 3, 4 and 5
with respect to the undersigned's holdings of and transactions in securities
issued by the Company, (b) revocation by the undersigned in a signed writing
delivered to the Company and the foregoing attorneys-in fact or (c) as to any
attorney-in-fact individually, until such attorney-in-fact is no longer employed
by the Company or employed by or a partner at Cooley LLP or another law firm
representing the Company, as applicable.

	IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of the date written below.

Date: April 1, 2020
Pontifax Late Stage GP Ltd.
By: /s/ Asaf Shinar
Name: Asaf Shinar
Title: CFO