Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Class A Common Stock^F1,F5,F6	May 29, 2018	C	383,538	—	A	383,538	I	Through Deerfield Special Situations Fund, L.P.
Class A Common Stock^F5,F6	May 29, 2018	P	333,333	$18.00	A	333,333	I	Through Deerfield Partners, L.P.
Class A Common Stock^F2,F5,F6	May 29, 2018	P	250,000	$19.8126	A	583,333	I	Through Deerfield Partners, L.P.
Class A Common Stock^F3,F5,F6	May 29, 2018	P	25,000	$20.9099	A	608,333	I	Through Deerfield Partners, L.P.
Class A Common Stock^F4,F5,F6	May 29, 2018	P	235,019	$19.2365	A	843,352	I	Through Deerfield Partners, L.P.

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Series C Preferred Stock^F1,F5,F6	—	May 29, 2018	C	383,538	D	—	—	Class A Common Stock	383,538	0	I

Explanation of responses

F1Each share of Series C Preferred Stock converted into one share of the Issuer's Class A Common Stock upon the closing of the Issuer's initial public offering. The number of shares reported herein gives effect to the 1-for-2.73235 reverse stock split of the Issuer's common stock and preferred stock effected by the Issuer in connection with its initial public offering.
F2The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $19.30 to $20.00, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in footnotes (2), (3) and (4) of this Form 4.
F3The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $20.78 to $21.00, inclusive.
F4The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $19.00 to $19.255, inclusive.
F5This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt, L.P. is the general partner of each of Deerfield Partners, L.P. and Deerfield Special Situations Fund, L.P. (the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt, L.P. and Deerfield Management Company, L.P.
F6In accordance with Instruction 4(b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

Remarks

Jonathan Isler, Attorney-in-Fact: Power of Attorney, which is hereby incorporated by reference to Exhibit 24 to a Form 3 with regard to Proteon Therapeutics, Inc. filed with the Securities and Exchange Commission on August 4, 2017 by Deerfield Special Situations Fund, L.P., Deerfield Partners, L.P., Deerfield International Master Fund, L.P., Deerfield Partners, L.P., Deerfield Private Design Fund IV, L.P., Deerfield Mgmt, L.P., Deerfield Mgmt III, L.P., Deerfield Mgmt IV, L.P., Deerfield Management Company, L.P., and James E. Flynn.