13G Filing: James E. Flynn and Proteon Therapeutics Inc (PRTO)

You can access the original SEC filing by clicking here.

Ownership Summary Table

Name Sole Voting Power Shared Voting Power Sole Dispositive Power Shared Dispositive Power Aggregate Amount Owned Power Percent of Class
Deerfield Mgmt 0 347,100 0 347,100 347,100 2.07%
Deerfield Management Company 0 1,224,899 0 1,224,899 1,224,899 7.30%
Deerfield Mgmt III 0 877,799 0 877,799 877,799 5.23%
Deerfield Special Situations Fund 0 149,676 0 149,676 149,676 0.89%
Deerfield Partners 0 86,867 0 86,867 86,867 0.52%
Deerfield International Master Fund 0 110,557 0 110,557 110,557 0.66%
Deerfield Private Design Fund III 0 877,799 0 877,799 877,799 5.23%
James E. Flynn 0 1,224,899 0 1,224,899 1,224,899 7.30%

Page 1 of 19 – SEC Filing

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

SCHEDULE 13G

(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS
FILED PURSUANT

TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS
THERETO FILED

PURSUANT TO RULE 13d-2(b)

(Amendment No. 4) *

Proteon Therapeutics, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

74371L109

(CUSIP Number)

May 1, 2017

(Date of Event Which Requires Filing of
this Statement)

Check the appropriate box to designate the
rule pursuant to which this Schedule is filed:

☐ Rule 13d-1(b)

☒ Rule 13d-1(c)

☐ Rule 13d-1(d)

(Page 1 of 15 Pages)

———-

* The remainder of this cover page shall be filled out for a
reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment
containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder
of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of
1934 or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act
(however, see the Notes).

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Page 2 of 19 – SEC Filing

CUSIP No. 74371L109 13G Page 2
of 15 Pages
1.

NAME OF REPORTING PERSONS

I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

Deerfield Mgmt, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)

(b) ☒

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 

 

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

347,100 (1)

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

347,100 (1)

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

347,100 (1)

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

2.07%

12.

TYPE OF REPORTING PERSON*

PN

__________________

(1) Comprised of shares of common stock held by Deerfield Special Situations Fund, L.P., Deerfield Partners,
L.P. and Deerfield International Master Fund, L.P., of which Deerfield Mgmt, L.P. is the general partner.

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Page 3 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 3
of 15 Pages
1.

NAME OF REPORTING PERSONS

I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

Deerfield Management Company, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)

(b) ☒

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 

 

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

1,224,899 (2)

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

1,224,899 (2)

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,224,899 (2)

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

7.30%

12.

TYPE OF REPORTING PERSON*

PN

__________________

(2) Comprised of shares of common stock held by Deerfield Private Design Fund III, L.P., Deerfield Special
Situations Fund, L.P., Deerfield Partners, L.P. and Deerfield International Master Fund, L.P., of which Deerfield Management Company,
L.P. is the investment advisor.

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Page 4 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 4
of 15 Pages
1.

NAME OF REPORTING PERSONS

I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

Deerfield Mgmt
III, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)

(b) ☒

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 

 

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

877,799 (3)

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

877,799 (3)

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

877,799 (3)

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

5.23%

12.

TYPE OF REPORTING PERSON*

PN

_________________

(3) Comprised of shares of common stock held by Deerfield Private Design Fund III, L.P., of which Deerfield
Mgmt III, L.P. is the general partner.

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Page 5 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 5
of 15 Pages
1.

NAME OF REPORTING PERSONS

I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

Deerfield Special
Situations Fund, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)

(b) ☒

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 

 

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

149,676

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

149,676

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

149,676

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

0.89%

12.

TYPE OF REPORTING PERSON*

PN

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Page 6 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 6
of 15 Pages
1.

NAME OF REPORTING PERSONS

I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

Deerfield Partners, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)

(b) ☒

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 

 

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

86,867

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

86,867

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

86,867

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

0.52%

12.

TYPE OF REPORTING PERSON*

PN

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Page 7 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 7
of 15 Pages
1.

NAME OF REPORTING PERSONS

I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

Deerfield International Master Fund, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)

(b) ☒

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

British Virgin Islands

 

 

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

110,557

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

110,557

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

110,557

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

0.66%

12.

TYPE OF REPORTING PERSON*

PN

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Page 8 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 8
of 15 Pages
1.

NAME OF REPORTING PERSONS

I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

Deerfield Private Design Fund III, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)

(b) ☒

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 

 

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

877,799

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

877,799

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

877,799

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

5.23%

12.

TYPE OF REPORTING PERSON*

PN

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Page 9 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 9
of 15 Pages
1.

NAME OF REPORTING PERSONS

I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

James E. Flynn

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)

(b) ☒

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

United States

 

 

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

1,224,899 (4)

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

1,224,899 (4)

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,224,899 (4)

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

7.30%

12.

TYPE OF REPORTING PERSON*

IN

__________________

(4) Comprised of shares of common stock held by Deerfield Private
Design Fund III, L.P., Deerfield Special Situations Fund, L.P., Deerfield Partners, L.P. and Deerfield International Master Fund,
L.P.

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Page 10 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 10
of 15 Pages

The sole purpose of this Amendment No. 4 to Schedule 13G is
to reflect the addition of Deerfield Partners, L.P. and Deerfield International Master Fund, L.P. as reporting persons.

Item 1(a). Name of Issuer:

Proteon
Therapeutics, Inc.

Item 1(b). Address of Issuer’s Principal Executive Offices:

200 West Street

Waltham, MA 02451

Item 2(a). Name of Person Filing:

James
E. Flynn, Deerfield Mgmt, L.P., Deerfield Mgmt III, L.P., Deerfield Management Company, L.P., Deerfield Special Situations Fund,
L.P., Deerfield Partners, L.P., Deerfield International
Master Fund, L.P. and Deerfield Private Design Fund III, L.P.

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

James E. Flynn, Deerfield Mgmt, L.P., Deerfield
Mgmt III, L.P., Deerfield Management Company, L.P., Deerfield Special Situations Fund, L.P., Deerfield Partners, L.P., Deerfield
International Master Fund, L.P. and Deerfield Private Design Fund III, L.P., 780 Third Avenue, 37th Floor, New York, NY 10017

Item 2(c). Citizenship:

Deerfield Mgmt, L.P., Deerfield Mgmt III, L.P., Deerfield
Management Company, L.P., Deerfield Private Design Fund III, L.P., Deerfield Special Situations Fund, L.P. and Deerfield Partners,
L.P. – Delaware limited partnerships;

Deerfield International Master Fund, L.P. –
British Virgin Islands limited partnership;

James E. Flynn – United States citizen

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

Common Stock

Item 2(e). CUSIP Number:

74371L109

Item 3.

If This Statement is Filed Pursuant to
Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:

(a)

Broker or dealer registered under Section 15 of the
Exchange Act.

(b) Bank as defined in Section 3(a)(6) of the Exchange Act.
(c)

Insurance company as defined in Section 3(a)(19) of
the Exchange Act.

(d)

Investment company registered under Section 8 of the
Investment Company Act.

(e) An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);
(f)

An employee benefit plan or endowment fund in accordance
with Rule 13d-1(b)(1)(ii)(F);

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Page 11 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 11
of 15 Pages
(g)

A parent holding company or control person in accordance
with Rule 13d-1(b)(1)(ii)(G);

(h)

A savings association as defined in Section 3(b) of
the Federal Deposit Insurance Act;

(i)

A church plan that is excluded from the definition
of an investment company under Section 3(c)(14) of the Investment Company Act;

(j) A non-U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J);
(k) Group, in accordance with Rule 13d-1(b)(1)(ii)(K).

If filing as a non-U.S. institution in accordance
with Rule 13d-1(b)(1)(ii)(J), please specify the type of institution: _________________

Item 4. Ownership.

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

(a) Amount beneficially owned**:

Deerfield Mgmt, L.P. – 347,100 shares

Deerfield Mgmt III, L.P. – 877,799 shares

Deerfield Management Company, L.P. – 1,224,899 shares

Deerfield Special Situations Fund, L.P. – 149,676
shares

Deerfield Partners, L.P. – 86,867 shares

Deerfield International Master Fund, L.P. –
110,557 shares

Deerfield Private Design Fund III, L.P. –
877,799 shares

James E. Flynn – 1,224,899 shares

(b) Percent of class**:

Deerfield Mgmt, L.P. – 2.07%

Deerfield Mgmt III, L.P. – 5.23%

Deerfield Management Company, L.P. – 7.30%

Deerfield Special Situations Fund, L.P. –
0.89%

Deerfield Partners, L.P. – 0.52%

Deerfield International Master Fund, L.P. –
0.66%

Deerfield Private Design Fund III, L.P. –
5.23%

James E. Flynn – 7.30%

(c) Number of shares as to which such person has**:
(i) Sole power to vote or to direct the vote: All Reporting Persons 0
(ii) Shared power to vote or to direct the vote:

Deerfield Mgmt, L.P. – 347,100

Deerfield Mgmt III, L.P. – 877,799

Deerfield Management Company, L.P. – 1,224,899

Deerfield Special Situations Fund, L.P. – 149,676

Deerfield Partners, L.P. – 86,867

Deerfield International Master Fund, L.P. –
110,557

Deerfield Private Design Fund III, L.P. – 877,799

James E. Flynn – 1,224,899

(iii)

Sole power to dispose or to direct the disposition of

All Reporting Persons – 0
(iv)

Shared power to dispose or to direct the disposition
of

Deerfield Mgmt, L.P. – 347,100

Deerfield Mgmt III, L.P. – 877,799

Deerfield Management Company, L.P. –
1,224,899

Deerfield Special Situations Fund, L.P.
– 149,676

Deerfield Partners, L.P. – 86,867

Deerfield International Master Fund,
L.P. – 110,557

Deerfield Private Design Fund III, L.P.
– 877,799

James E. Flynn – 1,224,899

**See footnotes on cover pages which are incorporated by reference
herein.

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Page 12 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 12
of 15 Pages
Item 5. Ownership of Five Percent or Less of a Class.

If this statement
is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more
than five percent of the class of securities check the following ☐.

Item 6. Ownership of More Than Five Percent on Behalf of Another Person.

If any other person
is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of,
such securities, a statement to that effect should be included in response to this item and, if such interest relates to more
than five percent of the class, such person should be identified. A listing of the shareholders of an investment company registered
under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not
required.

N/A
Item 7.

Identification and Classification of the Subsidiary
Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

If a parent holding
company or Control person has filed this schedule, pursuant to Rule 13d-1(b)(1)(ii)(G), so indicate under Item 3(g) and attach
an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company or control
person has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the
relevant subsidiary.

N/A
Item 8. Identification and Classification of Members of the Group.

If a group has filed
this schedule pursuant to ss.240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and
Item 3 classification of each member of the group. If a group has filed this schedule pursuant to ss.240.13d-1(c) or ss.240.13d-1(d),
attach an exhibit stating the identity of each member of the group.

See Exhibit B
Item 9. Notice of Dissolution of Group.

Notice of dissolution
of a group may be furnished as an exhibit stating the date of the dissolution and that all further filings with respect to transactions
in the security reported on will be filed, if required, by members of the group, in their individual capacity. See Item 5.

N/A

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Page 13 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 13
of 15 Pages
Item 10. Certifications.

“By signing below
I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for
the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired
and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities
solely in connection with a nomination under §240.14a–11.”

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Page 14 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 14
of 15 Pages

SIGNATURE

After reasonable inquiry and to the best
of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

DEERFIELD MGMT, L.P.

By: J.E. Flynn Capital, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD MANAGEMENT COMPANY, L.P.

By: Flynn Management LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD MGMT III, L.P.

By: J.E. Flynn Capital III, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD SPECIAL SITUATIONS FUND, L.P.

By: Deerfield Mgmt, L.P., General Partner

By: J.E. Flynn Capital, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD PARTNERS, L.P.

By: Deerfield Mgmt, L.P., General Partner

By: J.E. Flynn Capital, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD INTERNATIONAL MASTER FUND, L.P.

By: Deerfield Mgmt, L.P., General Partner

By: J.E. Flynn Capital, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD PRIVATE DESIGN FUND III, L.P.

By: Deerfield Mgmt III, L.P., General Partner

By: J.E. Flynn Capital III, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

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Page 15 of 19 – SEC Filing

CUSIP No.

74371L109

13G Page 15
of 15 Pages

JAMES E. FLYNN

/s/ Jonathan Isler

Jonathan Isler, Attorney-In-Fact

Date: May 2, 2017

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Page 16 of 19 – SEC Filing

Exhibit List

Exhibit A. Joint Filing Agreement.

Exhibit B. Item 8 Statement.

Exhibit C. Power of Attorney (1).

(1) Power of Attorney previously filed as Exhibit 24 to a Form
3 with regard to Editas Medicine, Inc. filed with the Securities and Exchange Commission on February 2, 2016 by Deerfield
Mgmt III, L.P., Deerfield Management Company, L.P., Deerfield Healthcare Innovations Fund, L.P., Deerfield Mgmt HIF, L.P., Deerfield
Private Design Fund III, L.P. and James E. Flynn.

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Page 17 of 19 – SEC Filing

Exhibit A

Joint Filing Agreement

The undersigned agree that this Schedule 13G, and all amendments
thereto, relating to the Common Stock of Proteon Therapeutics, Inc. shall be filed on behalf of the undersigned.

DEERFIELD MGMT, L.P.

By: J.E. Flynn Capital, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD MANAGEMENT COMPANY, L.P.

By: Flynn Management LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD MGMT III, L.P.

By: J.E. Flynn Capital III, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD SPECIAL SITUATIONS FUND, L.P.

By: Deerfield Mgmt, L.P., General Partner

By: J.E. Flynn Capital, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD PARTNERS, L.P.

By: Deerfield Mgmt, L.P., General Partner

By: J.E. Flynn Capital, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD INTERNATIONAL MASTER FUND, L.P.

By: Deerfield Mgmt, L.P., General Partner

By: J.E. Flynn Capital, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

DEERFIELD PRIVATE DESIGN FUND III, L.P.

By: Deerfield Mgmt III, L.P., General Partner

By: J.E. Flynn Capital III, LLC, General Partner

By: /s/ Jonathan Isler

      Jonathan Isler, Attorney-In-Fact

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Page 18 of 19 – SEC Filing

JAMES E. FLYNN

/s/ Jonathan Isler

Jonathan Isler, Attorney-In-Fact

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Page 19 of 19 – SEC Filing

Exhibit B

Due to the relationships between them,
the reporting persons hereunder may be deemed to constitute a “group” with one another for purposes of Section 13(d)(3)
of the Securities Exchange Act of 1934.

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