Exhibit 10.3


 


REGISTRATION RIGHTS AGREEMENT


 


This Registration Rights Agreement (this
 “Agreement”) is dated as of January 28, 2021, by and among Catabasis Pharmaceuticals, Inc., a Delaware
corporation (the “Company”), and the several purchasers signatory hereto (each, including its successors and
assigns, a “Purchaser” and collectively, the “Purchasers”).


 


This Agreement is made pursuant to the Stock
Purchase Agreement, dated as of January 28, 2021, between the Company and the Purchasers (the “Purchase Agreement”).


 


NOW, THEREFORE, IN CONSIDERATION of
the mutual covenants contained in this Agreement, and for other good and valuable consideration, the receipt and adequacy of which
are hereby acknowledged, the Company and each of the Purchasers agree as follows:


 


1.            DEFINITIONS.
Capitalized terms used and not otherwise defined herein that are defined in the Purchase Agreement shall have the meanings given
such terms in the Purchase Agreement. As used in this Agreement, the following terms shall have the following meanings:


 


“Affiliate” means any
Person that, directly or indirectly through one or more intermediaries, controls or is controlled by or is under common control
with a Person, as such terms are used in and construed under Rule 405 of the Securities Act of 1933, as amended.


 


“Business Day” means
any day except any Saturday, any Sunday, any day which is a federal legal holiday in the United States or any day on which banking
institutions in the State of New York are authorized or required by law or other governmental action to close; provided, however,
for clarification, commercial banks shall not be deemed to be authorized or required by law to remain closed due to “stay
at home”, “shelter-in-place”, “non-essential employee” or any other similar orders
or restrictions or the closure of any physical branch locations at the direction of any governmental authority so long as the electronic
funds transfer systems (including for wire transfers) of commercial banks in the State of New York are generally are open for use
by customers on such day.


 


“Closing Date” has the
meaning set forth in the Purchase Agreement.


 


“Commission” means the
United States Securities and Exchange Commission.


 


“Common Stock” means
the Company’s common stock, par value $0.001 per share, and stock of any other class of securities into which such securities
may hereafter be reclassified or changed.


 


“Effectiveness Deadline”
means, with respect to the Initial Registration Statement or the New Registration Statement, the 30th calendar day following
the Filing Deadline (or, in the event the Commission reviews and has comments to the Initial Registration Statement or the New
Registration Statement, the 60th calendar day following the Filing Deadline); provided, however,
that if the Company is notified by the Commission that the Initial Registration Statement or the New Registration Statement will
not be reviewed or is no longer subject to further review and comments, the Effectiveness Deadline as to such Registration Statement
shall be the fifth Trading Day following the date on which the Company is so notified if such date precedes the dates otherwise
required above; provided, further, that if the Effectiveness Deadline falls on a Saturday, Sunday or other
day that the Commission is closed for business, the Effectiveness Deadline shall be extended to the next Business Day on which
the Commission is open for business.


 






     


     


    

 





“Exchange Act” means
the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.


 


“Filing Deadline” means,
with respect to the Initial Registration Statement required to be filed pursuant to Section 2(a), the 90th calendar
day following the Closing Date, provided, however, that if the Filing Deadline falls on a Saturday, Sunday or other
day that the Commission is closed for business, the Filing Deadline shall be extended to the next Business Day on which the Commission
is open for business.


 


“Holder” or “Holders”
means the holder or holders, as the case may be, from time to time of Registrable Securities.


 


“Person” means an individual
or corporation, partnership, trust, incorporated or unincorporated association, joint venture, limited liability company, joint
stock company, government (or an agency or subdivision thereof) or other entity of any kind.


 


“Principal Trading Market”
means the Trading Market on which the Common Stock is primarily listed on and quoted for trading, which, as of the Closing Date,
shall be the Nasdaq Global Market.


 


“Proceeding” means an
action, claim, suit, investigation or proceeding (including, without limitation, an investigation or partial proceeding, such as
a deposition), whether commenced or threatened.


 


“Pro Rata Interest” means
the number of Registrable Securities beneficially held by any given Purchaser, relative to the total number of Registrable Securities
that are the subject of this Agreement.


 


“Prospectus” means the
prospectus included in a Registration Statement (including, without limitation, a prospectus that includes any information previously
omitted from a prospectus filed as part of an effective registration statement in reliance upon Rule 430B promulgated under
the Securities Act), as amended or supplemented by any prospectus supplement, with respect to the terms of the offering of any
portion of the Registrable Securities covered by a Registration Statement, and all other amendments and supplements to the Prospectus,
including post-effective amendments, and all material incorporated by reference or deemed to be incorporated by reference in such
Prospectus.


 






     


     


    

 


“Registrable Securities”
means all of (i) the Shares, (ii) any Common Stock issued to a Purchaser on the date hereof pursuant to that certain
Agreement and Plan of Merger, dated as of January 28, 2021, by and among the Company, Cabo Merger Sub I, Inc., Cabo Merger
Sub II, LLC and Quellis Biosciences, Inc., and (iii) any securities issued or issuable upon any stock split, dividend
or other distribution, recapitalization or similar event with respect to the foregoing, provided, that the Holder has
completed and delivered to the Company a Selling Shareholder Questionnaire; and provided, further, that
with respect to a particular Holder, such Holder’s Shares shall cease to be Registrable Securities upon the earliest to occur
of the following: (A) a sale pursuant to a Registration Statement or Rule 144 under the Securities Act (in which case,
only such security or securities sold by the Holder shall cease to be Registrable Securities); (B) becoming eligible for resale
by the Holder under Rule 144 without the requirement for the Company to be in compliance with the current public information
required thereunder and without volume or manner-of-sale restrictions; or (C) the expiration of two years from the
Closing Date.





 


“Registration Statements”
means any one or more registration statements of the Company filed under the Securities Act that covers the resale of any of the
Registrable Securities pursuant to the provisions of this Agreement (including without limitation the Initial Registration Statement,
the New Registration Statement and any Remainder Registration Statements), amendments and supplements to such Registration Statements,
including post-effective amendments, all exhibits and all material incorporated by reference or deemed to be incorporated by reference
in such Registration Statements.


 


“Rule 144” means
Rule 144 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time,
or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.


 


“Rule 415” means
Rule 415 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time,
or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.


 


“Rule 424” means
Rule 424 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time,
or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.


 


“SEC Guidance” means
(i) any publicly-available written or oral guidance, comments, requirements or requests of the Commission staff; provided,
that any such oral guidance, comments, requirements or requests are reduced to writing by the Commission and (ii) the Securities
Act.


 


“Securities Act” means
the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.


 


“Selling Shareholder Questionnaire”
means a questionnaire in the form attached as Annex B hereto, or such other form of questionnaire as may reasonably
be adopted by the Company from time to time.


 


“Series X Preferred Shares”
means the Series X Convertible Preferred Stock, par value $0.001 per share, of the Company.


 


“Shares” means the shares
of Common Stock which may be issued upon conversion of the Series X Preferred Shares.


 


“Trading Day” means a
day on which the Principal Trading Market is open for business.


 






     


     


    

 


“Trading Market” means
any of the following markets or exchanges on which the Common Stock is listed or quoted for trading on the date in question: the
NYSE American, the Nasdaq Capital Market, the Nasdaq Global Market, the Nasdaq Global Select Market, or the New York Stock Exchange
(or any successors to any of the foregoing).





 


2.             REGISTRATION.


 


(a)            On
or prior to the Filing Deadline, the Company shall prepare and file with the Commission a Registration Statement covering the resale
of all of the Registrable Securities not then registered on an existing and effective Registration Statement for an offering to
be made on a continuous basis pursuant to Rule 415 or, if Rule 415 is not available for offers and sales of the Registrable
Securities, by such other means of distribution of Registrable Securities as the Holders may reasonably specify (the “Initial
Registration Statement”). The Initial Registration Statement shall be on Form S-3 (except if the Company is
then ineligible to register for resale the Registrable Securities on Form S-3, in which case such registration shall
be on such other form available to register for resale the Registrable Securities as a secondary offering) subject to the provisions
of Section 2(d) and shall contain (except if otherwise required pursuant to written comments received from
the Commission upon a review of such Registration Statement) the “Plan of Distribution” section substantially in the
form attached hereto as Annex A (which may be modified to respond to comments, if any, provided by the Commission).
Notwithstanding the registration obligations set forth in this Section 2, in the event the Commission informs
the Company that all of the Registrable Securities cannot, as a result of the application of Rule 415, be registered for resale
as a secondary offering on a single registration statement, the Company agrees to promptly (i) inform each of the Holders
thereof and use its commercially reasonable efforts to file amendments to the Initial Registration Statement as required by the
Commission and/or (ii) withdraw the Initial Registration Statement and file a new registration statement (a “New
Registration Statement”), in either case covering the maximum number of Registrable Securities permitted to be registered
by the Commission, on Form S-3 or, if the Company is ineligible to register the Registrable Securities on Form S-3, such
other form available to register for resale the Registrable Securities as a secondary offering; provided, however,
that prior to filing such amendment or New Registration Statement, the Company shall be obligated to use its commercially reasonable
efforts to advocate with the Commission for the registration of all of the Registrable Securities in accordance with the SEC Guidance,
including without limitation, the Securities Act Rules Compliance and Disclosure Interpretations Question 612.09. Notwithstanding
any other provision of this Agreement, if any SEC Guidance sets forth a limitation of the number of Registrable Securities permitted
to be registered on a particular Registration Statement as a secondary offering (and notwithstanding that the Company used diligent
efforts to advocate with the Commission for the registration of all or a greater number of Registrable Securities), unless otherwise
directed in writing by a Holder as to its Registrable Securities, the number of Registrable Securities to be registered on such
Registration Statement will first be reduced by Registrable Securities not acquired pursuant to the Purchase Agreement (whether
pursuant to registration rights or otherwise), and second by Registrable Securities represented by Shares (applied, in the case
that some Shares may be registered, to the Holders in accordance with their respective Pro Rata Interests, subject to a determination
by the Commission that certain Holders must be reduced first based on the number of Shares held by such Holders). In the event
the Company amends the Initial Registration Statement or files a New Registration Statement, as the case may be, under clauses
(i) or (ii) above, the Company will use its commercially reasonable efforts to file with the Commission, as promptly
as allowed by Commission or SEC Guidance provided to the Company or to registrants of securities in general, one or more registration
statements on Form S-3 or such other form available to register for resale those Registrable Securities that were not
registered for resale on the Initial Registration Statement, as amended, or the New Registration Statement (the “Remainder
Registration Statements”).


 






     


     


    




 


(b)            The
Company shall use commercially reasonable efforts to cause each Registration Statement to be declared effective by the Commission
as soon as practicable and, with respect to the Initial Registration Statement or the New Registration Statement, as applicable,
no later than the Effectiveness Deadline (including filing with the Commission a request for acceleration of effectiveness in accordance
with Rule 461 promulgated under the Securities Act), and shall use commercially reasonable efforts to keep each Registration
Statement continuously effective under the Securities Act until the earliest of: (i) such time as all of the Registrable Securities
covered by such Registration Statement have been sold by the Holders; (ii) the date that all Registrable Securities covered
by such Registration Statement may be sold without volume or manner-of-sale restrictions pursuant to Rule 144 and
without the requirement for the Company to be in compliance with the current public information requirement under Rule 144;
or (iii) the date that is two years from the Closing Date (the “Effectiveness Period”). The Company shall
promptly notify the Holders of the effectiveness of a Registration Statement or any post-effective amendment thereto. The Company
shall file a final Prospectus with the Commission, in the manner and within the time period required by Rule 424(b) and
shall, if requested, provide the Holders with copies of the final Prospectus to be used in connection with the sale or other disposition
of the securities covered thereby. The Company shall promptly inform each Holder in writing if, at any time during the Effectiveness
Period, the Company does not satisfy the conditions specified in Rule 172 and, as a result thereof, the Holder is required
to deliver a Prospectus in connection with any disposition of Registrable Securities.


 


(c)            Each
Holder agrees to furnish to the Company a completed Selling Shareholder Questionnaire not more than five Trading Days following
the date of this Agreement. Each Holder further agrees that it shall not be entitled to be named as a selling securityholder in
the Registration Statement or use the Prospectus for offers and resales of Registrable Securities at any time, unless such Holder
has returned to the Company a completed and signed Selling Shareholder Questionnaire and any further information reasonably requested
by the Company. Each Holder acknowledges and agrees that the information in the Selling Shareholder Questionnaire or request for
further information as described in this Section 2(c) will be used by the Company in the preparation of the
Registration Statement and hereby consents to the inclusion of such information in the Registration Statement.


 


(d)            In
the event that Form S-3 is not available for the registration of the resale of Registrable Securities hereunder, the
Company shall (i) register the resale of the Registrable Securities on another appropriate form reasonably acceptable to the
Holders and (ii) undertake to register the Registrable Securities on Form S-3 promptly after such form is available, provided that
the Company shall maintain the effectiveness of the Registration Statement then in effect until such time as a Registration Statement
on Form S-3 covering the Registrable Securities has been declared effective by the Commission.


 






     


     


    

 


3.             REGISTRATION
PROCEDURES.





 


In connection with the Company’s registration
obligations hereunder, the Company shall:


 


(a)            Not
less than five Trading Days prior to the filing of each Registration Statement and not less than one Trading Day prior to the filing
of any related Prospectus or any amendment or supplement thereto (except for Annual Reports on Form 10-K, and Quarterly
Reports on Form 10-Q and Current Reports on Form 8-K and any similar or successor reports), (i) furnish
to each Holder copies of such Registration Statement, Prospectus or amendment or supplement thereto, as proposed to be filed, which
documents will be subject to the review of such Holder (it being acknowledged and agreed that if a Holder does not object to or
comment on the aforementioned documents within such five Trading Day or one Trading Day period, as the case may be, then the Holder
shall be deemed to have consented to and approved the use of such documents) and (ii) to the extent that such Holder is identified
in the Registration Statement as an “underwriter” (as defined under the Securities Act) use commercially reasonable
efforts to cause its officers and directors, counsel and independent registered public accountants to respond to such inquiries
as shall be necessary, in the reasonable opinion of respective counsel to each Holder, to conduct a reasonable investigation within
the meaning of the Securities Act. The Company shall not file any Registration Statement or amendment or supplement thereto in
a form to which a Holder reasonably objects in good faith, provided that, the Company is notified of such objection in writing
within the five Trading Day or one Trading Day period described above, as applicable.


 


(b)            (i) Prepare
and file with the Commission such amendments (including post-effective amendments) and supplements, to each Registration Statement
and the Prospectus used in connection therewith as may be necessary to keep such Registration Statement continuously effective
as to the applicable Registrable Securities for its Effectiveness Period; (ii) cause the related Prospectus to be amended
or supplemented by any required Prospectus supplement (subject to the terms of this Agreement), and, as so supplemented or amended,
to be filed pursuant to Rule 424; (iii) respond as promptly as reasonably practicable to any comments received from the
Commission with respect to each Registration Statement or any amendment thereto and, as promptly as reasonably possible, provide
the Holders true and complete copies of all correspondence from and to the Commission relating to such Registration Statement that
pertains to the Holders as “Selling Stockholders” but not any comments that would result in the disclosure to the Holders
of material and non-public information concerning the Company; and (iv) comply with the provisions of the Securities
Act and the Exchange Act with respect to the disposition of all Registrable Securities covered by a Registration Statement until
such time as all of such Registrable Securities shall have been disposed of (subject to the terms of this Agreement) in accordance
with the intended methods of disposition by the Holders thereof as set forth in such Registration Statement as so amended or in
such Prospectus as so supplemented; provided, however, that each Purchaser shall be responsible for the
delivery of the Prospectus to the Persons to whom such Purchaser sells any of the Shares (including in accordance with Rule 172
under the Securities Act), and each Purchaser agrees to dispose of Registrable Securities in compliance with the “Plan of
Distribution” described in the Registration Statement and otherwise in compliance with applicable federal and state securities
laws. In the case of amendments and supplements to a Registration Statement which are required to be filed pursuant to this Agreement
(including pursuant to this Section 3(b)) by reason of the Company filing a report on Form 10-K, Form 10-Q or
Form 8-K or any analogous report under the Exchange Act, the Company shall have incorporated such report by reference
into such Registration Statement, if applicable, or shall file such amendments or supplements with the Commission on the same day
on which the Exchange Act report which created the requirement for the Company to amend or supplement such Registration Statement
was filed.


 






     


     


    




 


(c)            Notify
the Holders (which notice shall (x) pursuant to clauses (iii) through (vi) hereof, be accompanied by an instruction
to suspend the use of the Prospectus until the requisite changes have been made and (y) in no event contain any material,
nonpublic information relating to the Company and/or any of its subsidiaries) as promptly as reasonably practicable (and, in the
case of (i)(A) below, not less than one Trading Day prior to such filing) and (if requested by any such Person) confirm such
notice in writing no later than one Trading Day following the day: (i)(A) when a Prospectus or any Prospectus supplement or
post-effective amendment to a Registration Statement is proposed to be filed; (B) when the Commission notifies the Company
whether there will be a “review” of such Registration Statement and whenever the Commission comments in writing on
any Registration Statement (in which case the Company shall provide to each of the Holders true and complete copies of all comments
that pertain to the Holders as a “Selling Stockholder” or to the “Plan of Distribution” and all written
responses thereto, but not information that the Company believes would constitute material and non-public information);
and (C) with respect to each Registration Statement or any post-effective amendment, when the same has become effective; (ii) of
any request by the Commission or any other Federal or state governmental authority for amendments or supplements to a Registration
Statement or Prospectus or for additional information that pertains to the Holders as “Selling Stockholders” or the
 “Plan of Distribution”; (iii) of the issuance by the Commission or any other federal or state governmental authority
of any stop order suspending the effectiveness of a Registration Statement covering any or all of the Registrable Securities or
the initiation of any Proceedings for that purpose; (iv) of the receipt by the Company of any notification with respect to
the suspension of the qualification or exemption from qualification of any of the Registrable Securities for sale in any jurisdiction,
or the initiation or threatening of any Proceeding for such purpose; (v) of the occurrence of any event or passage of time
that makes the financial statements included or incorporated by reference in a Registration Statement ineligible for inclusion
or incorporation by reference therein or any statement made in such Registration Statement or Prospectus or any document incorporated
or deemed to be incorporated therein by reference untrue in any material respect or that requires any revisions to such Registration
Statement, Prospectus or other documents so that, in the case of such Registration Statement or the Prospectus, as the case may
be, it will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein (in the case of any Prospectus, form of prospectus or supplement thereto, in light
of the circumstances under which they were made), not misleading and (vi) of the occurrence or existence of any pending corporate
development with respect to the Company that the Company reasonably believes may be material and that, in the reasonable determination
of the Company, makes it not in the best interest of the Company to allow continued availability of a Registration Statement or
Prospectus; provided that, any and all such information shall remain confidential to each Holder until such information
otherwise becomes public, unless disclosure by a Holder is required by law; and provided, further, that
notwithstanding each Holder’s agreement to keep such information confidential, each such Holder makes no acknowledgement
that any such information is material, non-public information.


 






     


     


    




 


(d)            Use
commercially reasonable efforts to avoid the issuance of, or, if issued, obtain the withdrawal of (i) any order suspending
the effectiveness of a Registration Statement, or (ii) any suspension of the qualification (or exemption from qualification)
of any of the Registrable Securities for sale in any jurisdiction, as soon as practicable.


 


(e)            To
the extent applicable, prior to any resale of Registrable Securities by a Holder, use its commercially reasonable efforts to register
or qualify or cooperate with the selling Holders in connection with the registration or qualification (or exemption from the registration
or qualification) of such Registrable Securities for the resale by the Holder under the securities or Blue Sky laws of such jurisdictions
within the United States as any Holder reasonably requests in writing, to keep each registration or qualification (or exemption
therefrom) effective during the Effectiveness Period and to do any and all other acts or things reasonably necessary to enable
the disposition in such jurisdictions of the Registrable Securities covered by each Registration Statement; provided,
that the Company shall not be required to qualify generally to do business in any jurisdiction where it is not then so qualified,
subject the Company to any material tax in any such jurisdiction where it is not then so subject or file a general consent to service
of process in any such jurisdiction.


 


(f)            Cooperate
with such Holder to facilitate the timely preparation and delivery of certificates or book entry statements, as applicable, representing
Registrable Securities to be delivered to a transferee pursuant to the Registration Statement, which certificates or statements
shall be free, to the extent permitted by the Purchase Agreement and under law, of all restrictive legends, and to enable such
Registrable Securities to be in such denominations and registered in such names as any such Holders may reasonably request.


 


(g)            Following
the occurrence of any event contemplated by Section 3(c), as promptly as reasonably practicable (taking into account
the Company’s good faith assessment of any adverse consequences to the Company and its shareholders of the premature disclosure
of such event), prepare a supplement or amendment, including a post-effective amendment, if applicable, to the affected Registration
Statements or a supplement to the related Prospectus or any document incorporated or deemed to be incorporated therein by reference,
and file any other required document so that, as thereafter delivered, no Registration Statement nor any Prospectus will contain
an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the
statements therein (in the case of any Prospectus, form of prospectus or supplement thereto, in light of the circumstances under
which they were made), not misleading. If the Company notifies the Holders in accordance with clauses (iii) through (vi) of Section 3(c) above
to suspend the use of any Prospectus until the requisite changes to such Prospectus have been made, then the Holders shall suspend
use of such Prospectus. The Company will use its commercially reasonable efforts to ensure that the use of the Prospectus may be
resumed as promptly as is practicable. The Company shall be entitled to exercise its right under this Section 3(g) to
suspend the availability of a Registration Statement and Prospectus. For the avoidance of doubt, any period of time for which the
availability of a Registration Statement and Prospectus are suspended pursuant to Section 2(c) shall be disregarded
when determining the time period allotted under this Section 3(g).


 






     


     


    

 


(h)            The
Company may require each selling Holder to furnish to the Company a certified statement as to (i) the number of shares of
Common Stock beneficially owned by such Holder and any Affiliate thereof, (ii) any Financial Industry Regulatory Authority
(“FINRA”) affiliations, (iii) any natural persons who have the power to vote or dispose of the Common Stock
and (iv) any other information as may be requested by the Commission, FINRA or any state securities commission.





 


(i)            The
Company shall cooperate with any registered broker through which a Holder proposes to resell its Registrable Securities in effecting
a filing with FINRA pursuant to FINRA Rule 5110 as requested by any such Holder, and following such filing the Company shall
pay the filing fee required for the first such filing within two Business Days of the request therefor.


 


4.             REGISTRATION
EXPENSES. All fees and expenses incident to the Company’s performance of or compliance with its obligations under this
Agreement (excluding any underwriting discounts and selling commissions and all legal fees and expenses of legal counsel for any
Holder) shall be borne by the Company whether or not any Registrable Securities are sold pursuant to a Registration Statement.
The fees and expenses referred to in the foregoing sentence shall include, without limitation, (i) all registration and filing
fees (including, without limitation, fees and expenses (A) with respect to filings required to be made with any Trading Market
on which the Common Stock are then listed for trading, (B) with respect to compliance with applicable state securities or
Blue Sky laws (including, without limitation, fees and disbursements of counsel for the Company in connection with Blue Sky qualifications
or exemptions of the Registrable Securities and determination of the eligibility of the Registrable Securities for investment under
the laws of such jurisdictions as requested by the Holders) and (C) if not previously paid by the Company in connection with Section 3(i) above,
with respect to any filing that may be required to be made by any broker through which a Holder intends to make sales of Registrable
Securities with FINRA pursuant to the FINRA Rule 5110, so long as the broker is receiving no more than a customary brokerage
commission in connection with such sale), (ii) printing expenses (including, without limitation, expenses of printing certificates
for Registrable Securities and of printing prospectuses if the printing of prospectuses is reasonably requested by the Holders
of a majority of the Registrable Securities included in the Registration Statement), and (iii) fees and disbursements of counsel
for the Company. In addition, the Company shall be responsible for all of its internal expenses incurred in connection with the
consummation of the transactions contemplated by this Agreement (including, without limitation, all salaries and expenses of its
officers and employees performing legal or accounting duties), the expense of any annual audit and the fees and expenses incurred
in connection with the listing of the Registrable Securities on any securities exchange as required hereunder. In no event shall
the Company be responsible for any underwriting, broker or similar fees or commissions of any Holder or, except to the extent provided
for in the Transaction Documents, any legal fees or other costs of the Holders.


 






     


     


    

 


5.            INDEMNIFICATION.


 


(a)            Indemnification
by the Company. The Company shall, notwithstanding any termination of this Agreement, indemnify, defend and hold harmless each
Holder, the officers, directors, agents, partners, members, managers, stockholders, Affiliates and employees of each of them, each
Person who controls any such Holder (within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange
Act) and the officers, directors, partners, members, managers, stockholders, agents and employees of each such controlling Person,
to the fullest extent permitted by applicable law, from and against any and all losses, claims, damages, liabilities, costs (including,
without limitation, reasonable costs of preparation and investigation and reasonable attorneys’ fees) and expenses (collectively,
 “Losses”), as incurred, that arise out of or are based upon (i) any untrue or alleged untrue statement
of a material fact contained in any Registration Statement, any Prospectus or any form of prospectus or in any amendment or supplement
thereto or in any preliminary prospectus, or arising out of or relating to any omission or alleged omission to state a material
fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus or form of prospectus
or supplement thereto, in light of the circumstances under which they were made) not misleading, or (ii) any violation or
alleged violation by the Company of the Securities Act, the Exchange Act or any state securities law or any rule or regulation
thereunder, in connection with the performance of its obligations under this Agreement, except to the extent, but only to the extent,
that (A) such untrue statements, alleged untrue statements, omissions or alleged omissions are based solely upon information
regarding such Holder furnished in writing to the Company by such Holder expressly for use therein, or to the extent that such
information relates to such Holder or such Holder’s proposed method of distribution of Registrable Securities and was reviewed
and approved in writing by such Holder expressly for use in the Registration Statement, such Prospectus or such form of Prospectus
or in any amendment or supplement thereto (it being understood that each Holder has approved Annex A hereto for
this purpose), (B) in the case of an occurrence of an event of the type specified in Section 3(c)(iii)-(vi),
related to the use by a Holder of an outdated or defective Prospectus after the Company has notified such Holder in writing that
the Prospectus is outdated or defective and prior to the receipt by such Holder of the Advice contemplated and defined in Section 6(d) below,
to the extent that following the receipt of the Advice the misstatement or omission giving rise to such Loss would have been corrected
or (C) to the extent that any such Losses arise out of the Purchaser’s (or any other indemnified Person’s) failure
to send or give a copy of the Prospectus or supplement (as then amended or supplemented), if required, pursuant to Rule 172
under the Securities Act (or any successor rule) to the Persons asserting an untrue statement or alleged untrue statement or alleged
untrue statement or omission or alleged omission at or prior to the written confirmation of the sale of Registrable Securities
to such Person if such statement or omission was corrected in such Prospectus or supplement. The Company shall notify the Holders
promptly of the institution, threat or assertion of any Proceeding arising from or in connection with the transactions contemplated
by this Agreement of which the Company is aware. Such indemnity shall remain in full force and effect regardless of any investigation
made by or on behalf of an Indemnified Party (as defined in Section 5(c)) and shall survive the transfer of the
Registrable Securities by the Holders.


 






     


     


    




 


(b)            Indemnification
by Holders. Each Holder shall, severally and not jointly, indemnify and hold harmless the Company, its directors, officers,
agents and employees, each Person who controls the Company (within the meaning of Section 15 of the Securities Act and Section 20
of the Exchange Act), and the directors, officers, agents or employees of such controlling Persons, to the fullest extent permitted
by applicable law, from and against all Losses, as incurred, arising out of or are based solely upon any untrue or alleged untrue
statement of a material fact contained in any Registration Statement, any Prospectus, or any form of prospectus, or in any amendment
or supplement thereto or in any preliminary prospectus, or arising out of or relating to any omission or alleged omission of a
material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus, or any
form of prospectus or supplement thereto, in light of the circumstances under which they were made) not misleading (i) to
the extent that such untrue statements or omissions are based solely upon information regarding such Holder furnished in writing
to the Company by such Holder expressly for use therein, (ii) to the extent that such information relates to such Holder or
such Holder’s proposed method of distribution of Registrable Securities and was reviewed and approved in writing by such
Holder expressly for use in a Registration Statement (it being understood that the Holder has approved Annex A hereto
for this purpose), such Prospectus or such form of Prospectus or in any amendment or supplement thereto or (iii) in the case
of an occurrence of an event of the type specified in Section 3(c)(iii)-(vi), to the extent related to
the use by such Holder of an outdated or defective Prospectus after the Company has notified such Holder in writing that the Prospectus
is outdated or defective and prior to the receipt by such Holder of the Advice contemplated in Section 6(c). In
no event shall the liability of any selling Holder hereunder be greater in amount than the dollar amount of the net proceeds received
by such Holder upon the sale of the Registrable Securities giving rise to such indemnification obligation.





 


(c)            Conduct
of Indemnification Proceedings. If any Proceeding shall be brought or asserted against any Person entitled to indemnity hereunder
(an “Indemnified Party”), such Indemnified Party shall promptly notify the Person from whom indemnity is sought
(the “Indemnifying Party”) in writing, and the Indemnifying Party shall have the right to assume the defense
thereof, including the employment of counsel reasonably satisfactory to the Indemnified Party and the payment of all reasonable
fees and expenses incurred in connection with defense thereof; provided, that the failure of any Indemnified Party
to give such notice shall not relieve the Indemnifying Party of its obligations or liabilities pursuant to this Agreement, except
(and only) to the extent that it shall be finally determined by a court of competent jurisdiction (which determination is not subject
to appeal or further review) that such failure shall have materially and adversely prejudiced the Indemnifying Party.


 


An Indemnified Party shall have the right
to employ separate counsel in any such Proceeding and to participate in the defense thereof, but the fees and expenses of such
counsel shall be at the expense of such Indemnified Party or Indemnified Parties unless: (1) the Indemnifying Party has agreed
in writing to pay such fees and expenses; (2) the Indemnifying Party shall have failed promptly to assume the defense of such
Proceeding and to employ counsel reasonably satisfactory to such Indemnified Party in any such Proceeding; or (3) the named
parties to any such Proceeding (including any impleaded parties) include both such Indemnified Party and the Indemnifying Party,
and such Indemnified Party shall have been advised by counsel that a conflict of interest exists if the same counsel were to represent
such Indemnified Party and the Indemnifying Party (in which case, if such Indemnified Party notifies the Indemnifying Party in
writing that it elects to employ separate counsel at the expense of the Indemnifying Party, the Indemnifying Party shall not have
the right to assume the defense thereof and such counsel shall be at the expense of the Indemnifying Party); provided,
that the Indemnifying Party shall not be liable for the fees and expenses of more than one separate firm of attorneys at any time
for all Indemnified Parties. The Indemnifying Party shall not be liable for any settlement of any such Proceeding effected without
its written consent, which consent shall not be unreasonably withheld, delayed or conditioned. No Indemnifying Party shall, without
the prior written consent of the Indemnified Party, effect any settlement of any pending Proceeding in respect of which any Indemnified
Party is a party, unless such settlement includes an unconditional release of such Indemnified Party from all liability on claims
that are the subject matter of such Proceeding.





 






     


     


    

 


Subject to the terms of this Agreement,
all fees and expenses of the Indemnified Party (including reasonable fees and expenses to the extent incurred in connection with
investigating or preparing to defend such Proceeding in a manner not inconsistent with this Section 5) shall be
paid to the Indemnified Party, as incurred, within twenty Trading Days of written notice thereof to the Indemnifying Party; provided,
that the Indemnified Party shall promptly reimburse the Indemnifying Party for that portion of such fees and expenses applicable
to such actions for which such Indemnified Party is finally judicially determined to not be entitled to indemnification hereunder).
The failure to deliver written notice to the Indemnifying Party within a reasonable time of the commencement of any such action
shall not relieve such Indemnifying Party of any liability to the Indemnified Party under this Section 5, except
to the extent that the Indemnifying Party is substantively and adversely prejudiced in its ability to defend such action.


 


(d)            Contribution.
If a claim for indemnification under Section 5(a) or 5(b) is unavailable to an Indemnified
Party or insufficient to hold an Indemnified Party harmless for any Losses, then each Indemnifying Party, in lieu of indemnifying
such Indemnified Party, shall contribute to the amount paid or payable by such Indemnified Party as a result of such Losses, in
such proportion as is appropriate to reflect the relative fault of the Indemnifying Party and Indemnified Party in connection with
the actions, statements or omissions that resulted in such Losses as well as any other relevant equitable considerations. The relative
fault of such Indemnifying Party and Indemnified Party shall be determined by reference to, among other things, whether any action
in question, including any untrue or alleged untrue statement of a material fact or omission or alleged omission of a material
fact, has been taken or made by, or relates to information supplied by, such Indemnifying Party or Indemnified Party, and the parties’
relative intent, knowledge, access to information and opportunity to correct or prevent such action, statement or omission. The
amount paid or payable by a party as a result of any Losses shall be deemed to include, subject to the limitations set forth in
this Agreement, any reasonable attorneys’ or other reasonable fees or expenses incurred by such party in connection with
any Proceeding to the extent such party would have been indemnified for such fees or expenses if the indemnification provided for
in this Section 5 was available to such party in accordance with its terms.


 


The parties hereto agree that it would not
be just and equitable if contribution pursuant to this Section 5(d) were determined by pro rata allocation
or by any other method of allocation that does not take into account the equitable considerations referred to in the immediately
preceding paragraph. Notwithstanding the provisions of this Section 5(d), (A) no Holder shall be required
to contribute, in the aggregate, any amount in excess of the amount by which the net proceeds actually received by such Holder
from the sale of the Registrable Securities subject to the Proceeding exceeds the amount of any damages that such Holder has otherwise
been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission and (B) no contribution
will be made under circumstances where the maker of such contribution would not have been required to indemnify the Indemnified
Party under the fault standards set forth in this Section 5. No person guilty of fraudulent misrepresentation
(within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any Person who was
not guilty of such fraudulent misrepresentation.





 






     


     


    

 


The indemnity and contribution agreements
contained in this Section 5 are in addition to any liability that the Indemnifying Parties may have to the
Indemnified Parties and are not in diminution or limitation of the indemnification provisions under the Purchase Agreement.


 


6.             MISCELLANEOUS.


 


(a)            Remedies.
In the event of a breach by the Company or by a Holder of any of their respective obligations under this Agreement, each Holder
or the Company, as the case may be, in addition to being entitled to exercise all rights granted by law and under this Agreement,
including recovery of damages, shall be entitled to seek specific performance of its rights under this Agreement. The Company and
each Holder agree that monetary damages may not provide adequate compensation for any losses incurred by reason of a breach by
it of any of the provisions of this Agreement and hereby further agrees that, in the event of any action for specific performance
in respect of such breach, it shall waive the defense that a remedy at law would be adequate.


 


(b)            Compliance.
Each Holder covenants and agrees that it will comply with the prospectus delivery requirements of the Securities Act as applicable
to it (unless an exemption therefrom is available) in connection with sales of Registrable Securities pursuant to the Registration
Statement and shall sell the Registrable Securities only in accordance with a method of distribution described in the Registration
Statement.


 


(c)            Discontinued
Disposition. By its acquisition of Registrable Securities, each Holder agrees that, upon receipt of a notice from the Company
of the occurrence of any event of the kind described in Section 3(c)(iii)-(vi), such Holder will forthwith
discontinue disposition of such Registrable Securities under a Registration Statement (but not, for the avoidance of doubt, pursuant
to Rule 144 to the extent then available) until it is advised in writing (the “Advice”) by the Company
that the use of the applicable Prospectus (as it may have been supplemented or amended) may be resumed. The Company will use its
commercially reasonable efforts to ensure that the use of the Prospectus may be resumed as promptly as is practicable.


 


(d)            No
Inconsistent Agreements. Neither the Company nor any of its subsidiaries has entered, as of the date hereof, nor shall the
Company or any of its subsidiaries, on or after the date hereof, enter into any agreement with respect to its securities, that
would have the effect of impairing the rights granted to the Holders in this Agreement or otherwise conflicts with the provisions
hereof.


 






     


     


    

 


(e)            Amendments
and Waivers. The provisions of this Agreement, including the provisions of this sentence, may not be amended, modified or supplemented,
or waived unless the same shall be in writing and signed by the Company and Holders holding no less than a majority of the then
outstanding Registrable Securities, provided that any party may give a waiver as to itself. Notwithstanding the foregoing, a waiver
or consent to depart from the provisions hereof with respect to a matter that relates exclusively to the rights of Holders and
that does not directly or indirectly affect the rights of other Holders may be given by Holders of all of the Registrable Securities
to which such waiver or consent relates; provided, however, that the provisions of this sentence may not
be amended, modified, or supplemented except in accordance with the provisions of the immediately preceding sentence.





 


(f)            Notices.
Any and all notices or other communications or deliveries required or permitted to be provided hereunder shall be delivered as
set forth in the Purchase Agreement.


 


(g)            Successors
and Assigns. This Agreement shall inure to the benefit of and be binding upon the successors and permitted assigns of each
of the parties and shall inure to the benefit of each Holder. Nothing in this Agreement, express or implied, is intended to confer
upon any party other than the parties hereto or their respective successors and assigns any rights, remedies, obligations, or liabilities
under or by reason of this Agreement, except as expressly provided in this Agreement. The Company may not assign its rights (except
by merger or in connection with another entity acquiring all or substantially all of the Company’s assets) or obligations
hereunder without the prior written consent of all the Holders of the then outstanding Registrable Securities. Each Holder may
assign its respective rights hereunder in the manner and to the Persons as permitted under the Purchase Agreement; provided in
each case that (i) the Holder agrees in writing with the transferee or assignee to assign such rights and related obligations
under this Agreement, and for the transferee or assignee to assume such obligations, and a copy of such agreement is furnished
to the Company within a reasonable time after such assignment, (ii) the Company is, within a reasonable time after such transfer
or assignment, furnished with written notice of the name and address of such transferee or assignee and the securities with respect
to which such registration rights are being transferred or assigned, (iii) at or before the time the Company received the
written notice contemplated by clause (ii) of this sentence, the transferee or assignee agrees in writing with the Company
to be bound by all of the provisions contained herein and (iv) the transferee or assignee is an “accredited investor,”
as that term is defined in Rule 501 of Regulation D.


 


(h)            Execution
and Counterparts. This Agreement may be executed in two or more counterparts, each of which when so executed shall be deemed
to be an original and, all of which taken together shall constitute one and the same Agreement and shall become effective when
counterparts have been signed by each party and delivered to the other party, it being understood that both parties need not sign
the same counterpart. In the event that any signature is delivered by e-mail delivery of a “.pdf” format
data file, such signature shall create a valid and binding obligation of the party executing (or on whose behalf such signature
is executed) with the same force and effect as if such “.pdf” signature were the original thereof.


 






     


     


    

 


(i)            Governing
Law. All questions concerning the construction, validity, enforcement and interpretation of this Agreement shall be governed
by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of
conflicts of law thereof. Each party agrees that all Proceedings concerning the interpretations, enforcement and defense of the
transactions contemplated by this Agreement (whether brought against a party hereto or its respective Affiliates, employees or
agents) shall be commenced exclusively in the New York Courts. Each party hereto hereby irrevocably submits to the exclusive jurisdiction
of the New York Courts for the adjudication of any dispute hereunder or in connection herewith or with any transaction contemplated
hereby or discussed herein, and hereby irrevocably waives, and agrees not to assert in any Proceeding, any claim that it is not
personally subject to the jurisdiction of any such New York Court, or that such Proceeding has been commenced in an improper or
inconvenient forum. Each party hereto hereby irrevocably waives personal service of process and consents to process being served
in any such Proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery)
to such party at the address in effect for notices to it under this Agreement and agrees that such service shall constitute good
and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to
serve process in any manner permitted by law. EACH PARTY HERETO HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED
BY APPLICABLE LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE
TRANSACTIONS CONTEMPLATED HEREBY.





 


(j)            Cumulative
Remedies. The remedies provided herein are cumulative and not exclusive of any other remedies provided by law.


 


(k)            Severability.
If any term, provision, covenant or restriction of this Agreement is held by a court of competent jurisdiction to be invalid, illegal,
void or unenforceable, the remainder of the terms, provisions, covenants and restrictions set forth herein shall remain in full
force and effect and shall in no way be affected, impaired or invalidated, and the parties hereto shall use their good faith reasonable
efforts to find and employ an alternative means to achieve the same or substantially the same result as that contemplated by such
term, provision, covenant or restriction. It is hereby stipulated and declared to be the intention of the parties that they would
have executed the remaining terms, provisions, covenants and restrictions without including any of such that may be hereafter declared
invalid, illegal, void or unenforceable.


 


(l)            Headings.
The headings in this Agreement are for convenience only and shall not limit or otherwise affect the meaning hereof.


 






     


     


    

 


(m)            Independent
Nature of Purchasers’ Obligations and Rights. The obligations of each Purchaser under this Agreement are several and
not joint with the obligations of any other Purchaser hereunder, and no Purchaser shall be responsible in any way for the performance
of the obligations of any other Purchaser hereunder. The decision of each Purchaser to purchase the Securities pursuant to the
Transaction Documents has been made independently of any other Purchaser. Nothing contained herein or in any other agreement or
document delivered at any closing, and no action taken by any Purchaser pursuant hereto or thereto, shall be deemed to constitute
the Purchasers as a partnership, an association, a joint venture or any other kind of entity, or create a presumption that the
Purchasers are in any way acting in concert with respect to such obligations or the transactions contemplated by this Agreement.
Each Purchaser acknowledges that no other Purchaser has acted as agent for such Purchaser in connection with making its investment
hereunder and that no Purchaser will be acting as agent of such Purchaser in connection with monitoring its investment in the Registrable
Securities or enforcing its rights under the Transaction Documents. Each Purchaser shall be entitled to protect and enforce its
rights, including, without limitation, the rights arising out of this Agreement, and it shall not be necessary for any other Purchaser
to be joined as an additional party in any Proceeding for such purpose. The Company acknowledges that each of the Purchasers has
been provided with the same Registration Rights Agreement for the purpose of closing a transaction with multiple Purchasers and
not because it was required or requested to do so by any Purchaser.





 


[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]




 






     


     


    

 



 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	CATABASIS,
	 	 	PHARMACEUTICALS INC.
	 	 	 
	 	 	 
	 	 	By:	 /s/ Jill C. Milne
	 	 	 	Name: Jill C. Milne
	 	 	 	Title: President and Chief Executive Officer




 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	NAME OF INVESTING ENTITY
 AUTHORIZED SIGNATORY
	 	 	 
	 	 	 
	 	 	By:	/s/ Benjamin Davey
	 	 	Name: Benjamin Davey
	 	 	Title: Managing Director
	 	 	 
	 	 	[***]
	 	 	 






     


     


    

 





IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	FAIRMOUNT HEALTHCARE FUND LP
 AUTHORIZED SIGNATORY
	 	 	 
	 	 	 
	 	 	By:	 /s/ Tomas Kiselak
	 	 	Name: Tomas Kiselak
	 	 	Title: Managing Member
	 	 	 
	 	 	[***]




 




     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	FAIRMOUNT HEALTHCARE FUND II LP
 AUTHORIZED SIGNATORY
	 	 	 
	 	 	 
	 	 	By:	/s/ Tomas Kiselak
	 	 	Name: Tomas Kiselak
	 	 	Title: Managing Member
	 	 	 
	 	 	[***]




 




     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	LOGOS GLOBAL MASTER FUND LP
	 	 	By: Logos GP LLC
	 	 	Its General Partner
	 	 	AUTHORIZED SIGNATORY
	 	 	 
	 	 	 
	 	 	By:	/s/ Arsani William
	 	 	Name: Arsani William
	 	 	Title: Managing Partner
	 	 	 
	 	 	[***]




 




     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	RA CAPITAL HEALTHCARE FUND, L.P.
	 	 	By: RA Capital Healthcare Fund GP, LLC
	 	 	Its: General Partner
	 	 	AUTHORIZED SIGNATORY
	 	 	 
	 	 	 
	 	 	By:	/s/ Rajeev Shah
	 	 	Name: Rajeev Shah
	 	 	Title: Manager
	 	 	 
	 	 	[***]




 




     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	COMMODORE CAPITAL MASTER L.P.
	 	 	 
	 	 	 
	 	 	By:	 /s/ R. Egen Atkinson, MD
	 	 	Name: R. Egen Atkinson, MD
	 	 	Title: Authorized Signatory
	 	 	 
	 	 	[***]




 




     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	SERRADO OPPORTUNITY FUND LLC
	 	 	AUTHORIZED SIGNATORY
	 	 	 
	 	 	 
	 	 	By:	/s/ Stewart J. Hen
	 	 	Name: Stewart J. Hen
	 	 	Title: Managing Member
	 	 	 
	 	 	[***]




 




     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	SPHERA BIOTECH MASTER FUND, LP
	 	 	 
	 	 	 
	 	 	By:	/s/ Doroh Breen
	 	 	Name: Doroh Breen
	 	 	Title: Director of General Partner
	 	 	 
	 	 	[***]




 




     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	 	CITADEL MULTI-STRATEGY EQUITIES MASTER FUND LTD.
	 	 	Citadel Advisors LLC, its portfolio manager
	 	 	 
	 	 	 
	 	 	By:	 /s/ Shellane Mulcahy
	 	 	Name: Shellane Mulcahy
	 	 	Title: Authorized Signatory
	 	 	 
	 	 	[***]




 




     


     


    





 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	PERCEPTIVE LIFE SCIENCES MASTER FUND, LTD.
	 	 
	 	 
	 	By: 	/s/ James Mannix
	 	Name: James Mannix
	 	Title: COO
	 	 
	 	 
	 	PERCEPTIVE XONTOGENY VENTURE FUND, LP
	 	By: Perceptive Xontogeny Venture GP LLC, its general partner
	 	 
	 	 
	 	By: 	/s/ James Mannix
	 	Name: James Mannix
	 	Title: COO
	 	 
	 	 
	 	By: 	/s/ Frederick Callori
	 	Name: Frederick Callori
	 	Title: Partner
	 	 
	 	[***]



 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	CRMA SPV, L.P.
	 	 
	 	 
	 	By: 	/s/ Bihua Chen
	 	By: Cormorant Asset Management, LP, its Attorney-in-fact
	 	Name: Bihua Chen
	 	Title: Managing Member
	 	 
	 	[***]



 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	CORMORANT GLOBAL HEALTHCARE MASTER FUND, LP
	 	 
	 	 
	 	By: 	/s/ Bihua Chen
	 	By: Cormorant Global Healthcare GP, LLC
	 	Name: Bihua Chen
	 	Title: Managing Member
	 	 
	 	[***]



 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	BOXER CAPITAL, LLC
	 	 
	 	 
	 	By: 	/s/ Aaron Davis
	 	Name: Aaron Davis
	 	Title: Chief Executive Officer
	 	 
	 	[***]



 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	MVA INVESTORS, LLC
	 	 
	 	 
	 	By: 	/s/ Aaron Davis
	 	Name: Aaron Davis
	 	Title: Chief Executive Officer
	 	 
	 	[***]



 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	ACUTA CAPITAL FUND, LP
	 	By: Acuta Capital Partners, LLC
	 	Its: General Partner
	 	AUTHORIZED SIGNATORY
	 	 
	 	 
	 	By: 	/s/ Scott R. Smith
	 	Name: Scott R. Smith
	 	Title: Chief Operating Officer
	 	 
	 	 
	 	ACUTA OPPORTUNITY FUND, LP
	 	By: Acuta Capital Partners, LLC
	 	Its: General Partner
	 	AUTHORIZED SIGNATORY
	 	 
	 	 
	 	By: 	/s/ Scott R. Smith
	 	Name: Scott R. Smith
	 	Title: Chief Operating Officer
	 	 
	 	[***]



 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	VENROCK HEALTHCARE CAPITAL PARTNERS EG L.P.
	 	By: VHCP Management EG, LLC, its general partner
	 	 
	 	 
	 	By: 	/s/ Nimish Shah
	 	Name: Nimish Shah
	 	Title: Authorized Signatory
	 	 
	 	[***]



 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	VENROCK HEALTHCARE CAPITAL PARTNERS III L.P.
	 	By: VHCP Management III, LLC, its general partner
	 	By: VR Advisor, LLC, its manager
	 	 
	 	 
	 	By: 	/s/ Nimish Shah
	 	Name: Nimish Shah
	 	Title: Authorized Signatory
	 	 
	 	 
	 	VHCP CO-INVESTMENT HOLDINGS III, LLC
	 	By: VHCP Management III, LLC, its manager
	 	By: VR Advisor, LLC, its manager
	 	 
	 	 
	 	By: 	/s/ Nimish Shah
	 	Name: Nimish Shah
	 	Title: Authorized Signatory
	 	 
	 	[***]



 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	VENROCK HEALTHCARE CAPITAL PARTNERS II L.P.
	 	By: VHCP Management II, LLC, its general partner
	 	By: VR Advisor, LLC, its manager
	 	 
	 	 
	 	By: 	/s/ Nimish Shah
	 	Name: Nimish Shah
	 	 
	 	 
	 	VHCP CO-INVESTMENT HOLDINGS II, LLC
	 	By: VHCP Management II, LLC, its manager
	 	By: VR Advisor, LLC, its manager
	 	 
	 	 
	 	By: 	/s/ Nimish Shah
	 	Name: Nimish Shah
	 	Title: Authorized Signatory
	 	 
	 	[***]



 






     


     


    

 


IN WITNESS WHEREOF, the parties have executed
this Registration Rights Agreement as of the date first written above.


 


	 	ACORN BIOVENTURES, L.P.
	 	By: Acorn Capital Advisors GP, LLC, a Delaware limited liability company
	 	Its: General Partner
	 	 
	 	 
	 	By: 	/s/ Anders Hove
	 	Name: Anders Hove
	 	Title: Member
	 	 
	 	[***]


 






     


     


    

 



ANNEX A


 


PLAN OF DISTRIBUTION


 


We are registering the shares of common
stock of Catabasis Pharmaceuticals, Inc., par value of $0.001 per share, or the Common Stock, which we refer to herein as
Shares, issued to the selling stockholders to permit the resale of these Shares by the holders of the Shares from time to time
after the date of this prospectus. We will not receive any of the proceeds from the sale by the selling stockholders of the Shares.
We will, or will procure to, bear all fees and expenses incident to our obligation to register the Shares.


 


The selling stockholders may sell all or
a portion of the Shares beneficially owned by them and offered hereby from time to time directly or through one or more underwriters,
broker-dealers or agents. If the Shares are sold through underwriters or broker-dealers, the selling stockholders will be responsible
for underwriting discounts or commissions or agent’s commissions. The Shares may be sold on any national securities exchange
or quotation service on which the securities may be listed or quoted at the time of sale, in the over-the-counter market
or in transactions otherwise than on these exchanges or systems or in the over-the-counter market and in one or more
transactions at fixed prices, at prevailing market prices at the time of the sale, at varying prices determined at the time of
sale, or at negotiated prices. These sales may be effected in transactions, which may involve crosses or block transactions. The
selling stockholders may use any one or more of the following methods when selling shares:


 


		·	ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;



 


		·	block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the
block as principal to facilitate the transaction;



 


		·	purchases by a broker-dealer as principal and resale by the broker-dealer for its account;



 


		·	an exchange distribution in accordance with the rules of the applicable exchange;



 


		·	privately negotiated transactions;



 


		·	settlement of short sales;



 


		·	broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per
share;



 


		·	through the writing or settlement of options or other hedging transactions, whether such options are listed on an options exchange
or otherwise;



 


		·	a combination of any such methods of sale; and



 


		·	any other method permitted pursuant to applicable law.



 






     


     


    

 


The selling stockholders also may resell
all or a portion of the shares in open market transactions in reliance upon Rule 144 under the Securities Act, as amended,
or the Securities Act, as permitted by that rule, or Section 4(a)(1) under the Securities Act, if available, rather than
under this prospectus, provided that they meet the criteria and conform to the requirements of those provisions.


 


Broker-dealers engaged by the selling stockholders
may arrange for other broker-dealers to participate in sales. If the selling stockholders effect such transactions by selling Shares
to or through underwriters, broker-dealers or agents, such underwriters, broker-dealers or agents may receive commissions in the
form of discounts, concessions or commissions from the selling stockholders or commissions from purchasers of the Shares for whom
they may act as agent or to whom they may sell as principal. Such commissions will be in amounts to be negotiated, but, except
as set forth in a supplement to this Prospectus, in the case of an agency transaction will not be in excess of a customary brokerage
commission in compliance with FINRA Rule 2121; and in the case of a principal transaction a markup or markdown in compliance
with FINRA IM-2121.01.


 


In connection with sales of the Shares or
otherwise, the selling stockholders may enter into hedging transactions with broker-dealers or other financial institutions, which
may in turn engage in short sales of the Shares in the course of hedging in positions they assume. The selling stockholders may
also sell Shares short and if such short sale shall take place after the date that this Registration Statement is declared effective
by the Commission, the selling stockholders may deliver Shares covered by this prospectus to close out short positions and to return
borrowed shares in connection with such short sales. The selling stockholders may also loan or pledge Shares to broker-dealers
that in turn may sell such shares, to the extent permitted by applicable law. The selling stockholders may also enter into option
or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities
which require the delivery to such broker-dealer or other financial institution of shares offered by this prospectus, which shares
such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect
such transaction).


 


The selling stockholders may, from time
to time, pledge or grant a security interest in some or all of the Shares owned by them and, if they default in the performance
of their secured obligations, the pledgees or secured parties may offer and sell the Shares from time to time pursuant to this
prospectus or any amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act
of 1933, amending, if necessary, the list of selling stockholders to include the pledgee, transferee or other successors in interest
as selling stockholders under this prospectus. The selling stockholders also may transfer and donate the Shares in other circumstances
in which case the transferees, donees, pledgees or other successors in interest will be the selling beneficial owners for purposes
of this prospectus.


 


The selling stockholders and any broker-dealer
or agents participating in the distribution of the Shares may be deemed to be “underwriters” within the meaning of
Section 2(11) of the Securities Act in connection with such sales. In such event, any commissions paid, or any discounts or
concessions allowed to, any such broker-dealer or agent and any profit on the resale of the shares purchased by them may be deemed
to be underwriting commissions or discounts under the Securities Act. Selling Stockholders who are “underwriters” within
the meaning of Section 2(11) of the Securities Act will be subject to the applicable prospectus delivery requirements of the
Securities Act including Rule 172 thereunder and may be subject to certain statutory liabilities of, including but not limited
to, Sections 11, 12 and 17 of the Securities Act and Rule 10b-5 under the Securities Exchange Act of 1934, as amended, or
the Exchange Act.


 






     


     


    

 


Each selling stockholder has informed the
Company that it is not a registered broker-dealer and does not have any written or oral agreement or understanding, directly or
indirectly, with any person to distribute the Shares. Upon the Company being notified in writing by a selling stockholder that
any material arrangement has been entered into with a broker-dealer for the sale of Common Stock through a block trade, special
offering, exchange distribution or secondary distribution or a purchase by a broker or dealer, a supplement to this prospectus
will be filed, if required, pursuant to Rule 424(b) under the Securities Act, disclosing (i) the name of each such
selling stockholder and of the participating broker-dealer(s), (ii) the number of shares involved, (iii) the price at
which such the Shares were sold, (iv) the commissions paid or discounts or concessions allowed to such broker-dealer(s), where
applicable, (v) that such broker-dealer(s) did not conduct any investigation to verify the information set out or incorporated
by reference in this prospectus, and (vi) other facts material to the transaction. In no event shall any broker-dealer receive
fees, commissions and markups, which, in the aggregate, would exceed eight percent (8.0%).


 


Under the securities laws of some U.S. states,
the Shares may be sold in such states only through registered or licensed brokers or dealers. In addition, in some U.S. states
the Shares may not be sold unless such shares have been registered or qualified for sale in such state or an exemption from registration
or qualification is available and is complied with.


 


There can be no assurance that any selling
stockholder will sell any or all of the Shares registered pursuant to the shelf registration statement, of which this prospectus
forms a part.


 


Each selling stockholder and any other person
participating in such distribution will be subject to applicable provisions of the Exchange Act and the rules and regulations
thereunder, including, without limitation, to the extent applicable, Regulation M of the Exchange Act, which may limit the timing
of purchases and sales of any of the Shares by the selling stockholder and any other participating person. To the extent applicable,
Regulation M may also restrict the ability of any person engaged in the distribution of the Shares to engage in market-making activities
with respect to the Shares. All of the foregoing may affect the marketability of the Shares and the ability of any person or entity
to engage in market-making activities with respect to the Shares.


 


We will pay all expenses of the registration
of the Shares pursuant to the registration rights agreement, including, without limitation, Securities and Exchange Commission
filing fees and expenses of compliance with state securities or “blue sky” laws; provided, however,
that each selling stockholder will pay all underwriting discounts and selling commissions, if any and any related legal expenses
incurred by it. We will indemnify the selling stockholders against certain liabilities, including some liabilities under the Securities
Act, in accordance with the registration rights agreement, or the selling stockholders will be entitled to contribution. We may
be indemnified by the selling stockholders against civil liabilities, including liabilities under the Securities Act, that may
arise from any written information furnished to us by the selling stockholders specifically for use in this prospectus, in accordance
with the related registration rights agreements, or we may be entitled to contribution.


 






     


     


    

 


ANNEX B


 


SELLING STOCKHOLDER NOTICE AND QUESTIONNAIRE


 


The undersigned holder of shares of the
(i) common stock, par value $0.001 per share, of Catabasis Pharmaceuticals, Inc. (the “Company”) and/or
(ii) Series X Convertible Preferred Stock, par value $0.001 per share, of the Company issued pursuant to a certain Stock
Purchase Agreement by and among the Company and the Purchasers named therein, dated as of January 28, 2021 (the “Agreement”),
understands that the Company intends to file with the Securities and Exchange Commission a registration statement on Form S-3 (the
 “Resale Registration Statement”) for the registration and the resale under Rule 415 of the Securities Act
of 1933, as amended (the “Securities Act”), of the Registrable Securities in accordance with the terms of the
Agreement. All capitalized terms not otherwise defined herein shall have the meanings ascribed thereto in the Agreement.


 


In order to sell or otherwise dispose of
any Registrable Securities pursuant to the Resale Registration Statement, a holder of Registrable Securities generally will be
required to be named as a selling stockholder in the related prospectus or a supplement thereto (as so supplemented, the “Prospectus”),
deliver the Prospectus to purchasers of Registrable Securities (including pursuant to Rule 172 under the Securities Act) and
be bound by the provisions of the Agreement (including certain indemnification provisions, as described below). Holders must complete
and deliver this Notice and Questionnaire in order to be named as selling stockholders in the Prospectus. Holders of Registrable
Securities who do not complete, execute and return this Notice and Questionnaire within five Trading Days following the date of
the Agreement (1) may not be named as selling stockholders in the Resale Registration Statement or the Prospectus and (2) may
not use the Prospectus for resales of Registrable Securities.


 


Certain legal consequences arise from being
named as a selling stockholder in the Resale Registration Statement and the Prospectus. Holders of Registrable Securities are advised
to consult their own securities law counsel regarding the consequences of being named or not named as a selling stockholder in
the Resale Registration Statement and the Prospectus.


 


NOTICE


 


The undersigned holder (the “Selling
Stockholder”) of Registrable Securities hereby gives notice to the Company of its intention to sell or otherwise dispose
of Registrable Securities owned by it and listed below in Item (3), unless otherwise specified in Item (3), pursuant to the Resale
Registration Statement. The undersigned, by signing and returning this Notice and Questionnaire, understands and agrees that it
will be bound by the terms and conditions of this Notice and Questionnaire and the Agreement.


 


The undersigned hereby provides the following
information to the Company and represents and warrants that such information is accurate and complete:


 






     


     


    

 


QUESTIONNAIRE


 


		1.	Name.



 


		(a)	Full Legal Name of Selling Stockholder: _____________________________________



 


(b)          Full
Legal Name of Registered Holder (if not the same as (a) above) through which Registrable Securities Listed in Item 3 below
are held: _________________________________


 


(c)          Full
Legal Name of Natural Control Person (which means a natural person who directly or indirectly alone or with others has power to
vote or dispose of the securities covered by the questionnaire): ________________________________________________________________


 


		2.	Contact Information for Notices to Selling Stockholder.



 


Address: _____________________________________________________________________________


 


Telephone: ___________________________________________________________________________


 


Fax :________________________________________________________________________________


 


Contact Person: ______________________________________________________________________


 


E-mail address of Contact Person: _________________________________________________________


 


		3.	Social Security Number or Taxpayer identification
number.



 


Social Security Number or Taxpayer identification number of
Selling Stockholder:


 


__________________________________


 


		4.	Beneficial Ownership of Registrable Securities Issuable
Pursuant to the Purchase Agreement.



 


Type and Number of Registrable Securities beneficially owned
and issued pursuant to the Agreement: __________________________________________________________________


 


		5.	Broker-Dealer Status.



 


		(a)	Are you a broker-dealer?



 


Yes
 ̈ No  ̈


 


		(b)	If “yes” to Section 4(a), did you receive
your Registrable Securities as compensation for investment banking services to the Company?



 


Yes
 ̈ No  ̈


 






     


     


    

 


Note: If no, the Commission’s staff has indicated that
you should be identified as an underwriter in the Registration Statement.


 


		(c)	Are you an affiliate of a broker-dealer?



 


Yes
 ̈ No  ̈


 


Note: If yes, provide a narrative explanation below:


 


(d)   If
you are an affiliate of a broker-dealer, do you certify that you bought the Registrable Securities in the ordinary course of business,
and at the time of the purchase of the Registrable Securities to be resold, you had no agreements or understandings, directly or
indirectly, with any person to distribute the Registrable Securities?


 


Yes
 ̈ No  ̈


 


Note: If no, the Commission’s staff has indicated that
you should be identified as an underwriter in the Registration Statement.


 


		6.	Beneficial Ownership of Other Securities of the Company
Owned by the Selling Stockholder.



 


Except as set forth below in this Item 6, the undersigned
is not the beneficial or registered owner of any securities of the Company other than the Registrable Securities listed above in
Item 3.


 


Type and amount of other securities beneficially owned: ______________________________


 


		7.	Relationships with the Company.



 


Except as set forth below, neither the undersigned nor any
of its affiliates, officers, directors or principal equity holders (owners of 5% of more of the equity securities of the undersigned)
has held any position or office or has had any other material relationship with the Company (or its predecessors or affiliates)
during the past three years.


 


State any exceptions here: _______________________________________________________


 


		8.	Plan of Distribution.



 


The undersigned has reviewed the form of Plan of Distribution
attached as Annex A to the Registration Rights Agreement, and hereby confirms that, except as set forth below, the information
contained therein regarding the undersigned and its plan of distribution is correct and complete.


 


State any exceptions here: ________________________________________________________


 


***********


 






     


     


    

 


The Company hereby advises the undersigned that the Commission
currently takes the position that coverage of Short Sales (as defined in the Purchase Agreement) of shares of common stock “against
the box” prior to effectiveness of a resale registration statement with securities included in such registration statement
would be a violation of Section 5 of the Securities Act, as set forth in Item 239.10 of the Securities Act Rules Compliance
and Disclosure Interpretations compiled by the Office of Chief Counsel, Division of Corporate Finance.


 


The undersigned agrees to promptly notify the Company of any
inaccuracies or changes in the information provided herein that may occur subsequent to the date hereof and prior to the effective
date of any applicable Resale Registration Statement. All notices hereunder and pursuant to the Agreement shall be made in writing,
by hand delivery, confirmed or facsimile transmission, first-class mail or air courier guaranteeing overnight delivery at the address
set forth below. In the absence of any such notification, the Company shall be entitled to continue to rely on the accuracy of
the information in this Notice and Questionnaire.


 


By signing below, the undersigned consents to the disclosure
of the information contained herein in its answers to Items (1) through (8) above and the inclusion of such information
in the Resale Registration Statement and the Prospectus. The undersigned understands that such information will be relied upon
by the Company in connection with the preparation or amendment of any such Registration Statement and the Prospectus.


 


By signing below, the undersigned acknowledges that it understands
its obligation to comply, and agrees that it will comply, with the provisions of the Exchange Act and the rules and regulations
thereunder, particularly Regulation M in connection with any offering of Registrable Securities pursuant to the Resale Registration
Statement. The undersigned also acknowledges that it understands that the answers to this Questionnaire are furnished for use in
connection with Registration Statements filed pursuant to the Registration Rights Agreement and any amendments or supplements thereto
filed with the Commission pursuant to the Securities Act.


 


I confirm that, to the best of my knowledge and belief, the
foregoing statements (including without limitation the answers to this Questionnaire) are correct.


 






     


     


    

 


IN WITNESS WHEREOF the undersigned, by authority duly given,
has caused this Questionnaire to be executed and delivered either in person or by its duly authorized agent.


 


	Dated:	Beneficial Owner:
	 	 	 
	 	By:	

	 	 	Name:
	 	 	Title:


 


Please scan a copy of the completed and executed notice and
questionnaire, and return to bharshbarger@catabasis.com.