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

NAME OF REPORTING PERSONS

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

Deerfield Mgmt, L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)
☐

(b) ☒

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

SOLE VOTING POWER

0

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)

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

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

2.07%

TYPE OF REPORTING PERSON*

PN

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NAME OF REPORTING PERSONS

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

Deerfield Management Company, L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)
☐

(b) ☒

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

SOLE VOTING POWER

0

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)

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

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

7.30%

TYPE OF REPORTING PERSON*

PN

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NAME OF REPORTING PERSONS

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

Deerfield Mgmt
III, L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)
☐

(b) ☒

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

SOLE VOTING POWER

0

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)

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

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

5.23%

TYPE OF REPORTING PERSON*

PN

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NAME OF REPORTING PERSONS

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

Deerfield Special
Situations Fund, L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)
☐

(b) ☒

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

SOLE VOTING POWER

0

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

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

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

0.89%

TYPE OF REPORTING PERSON*

PN

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NAME OF REPORTING PERSONS

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

Deerfield Partners, L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)
☐

(b) ☒

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

SOLE VOTING POWER

0

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

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

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

0.52%

TYPE OF REPORTING PERSON*

PN

74371L109

NAME OF REPORTING PERSONS

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

Deerfield International Master Fund, L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)
☐

(b) ☒

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

British Virgin Islands

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

SOLE VOTING POWER

0

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

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

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

0.66%

TYPE OF REPORTING PERSON*

PN

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NAME OF REPORTING PERSONS

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

Deerfield Private Design Fund III, L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)
☐

(b) ☒

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

SOLE VOTING POWER

0

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

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

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

5.23%

TYPE OF REPORTING PERSON*

PN

74371L109

NAME OF REPORTING PERSONS

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

James E. Flynn

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a)
☐

(b) ☒

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

United States

 NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

SOLE VOTING POWER

0

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)

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

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

7.30%

TYPE OF REPORTING PERSON*

IN

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Proteon
Therapeutics, Inc.

200 West Street

Waltham, MA 02451

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.

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

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

Common Stock

74371L109

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

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

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

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

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

74371L109

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;

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

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

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

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%

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

Sole power to dispose or to direct the disposition of

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

74371L109

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 ☐.

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.

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.

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.

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.

74371L109

“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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