Salarius Pharmaceuticals, Inc. — Director's Dealing 2016

Jun 17, 2016

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Flex Pharma, Inc. (FLKS)
CIK: 0001615219
Period of Report: 2016-06-15

Reporting Person: Westphal Christoph H (Director, President and CEO, 10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2016-06-15	Common Stock	P	2900	$11.24	Acquired	3195561	Indirect
2016-06-16	Common Stock	P	2900	$11.10	Acquired	3198461	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	3925248	Direct

Footnotes

F1: The price in Column 4 is a weighted average purchase price. The prices actually received ranged from $11.15 to $11.30. The reporting person will provide to the Issuer, any security holder of the Issuer, or the SEC staff, upon request, information regarding the number of shares purchased at each price within the range.

F2: On June 15, 2016, Longwood Fund III, L.P. ("Longwood Fund III") purchased 2,900 shares of common stock of the Issuer (the "Common Shares"). Following such purchase, Longwood Fund III owned 498,297 Common Shares and Longwood Fund II, L.P. ("Longwood Fund II") owned 2,697,264 Common Shares.

F3: Longwood Fund II GP, LLC is the ultimate General Partner of Longwood Fund II and Longwood Fund III GP, LLC is the ultimate General Partner of Longwood Fund III. Christoph Westphal, M.D., Ph.D., Richard Aldrich and Michelle Dipp, M.D., Ph.D. (collectively, the "Managers") are managers of Longwood Fund II GP, LLC and Longwood Fund III GP, LLC, and, as such, may be deemed to have shared voting and dispositive power with respect to the Issuer's securities held by Longwood Fund II and Longwood Fund III (the "Longwood Shares"). Each of the Managers disclaims beneficial ownership of the Longwood Shares, except to the extent of their respective pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the shares for purposes of Section 16 or for any other purpose.

F4: The price in Column 4 is a weighted average purchase price. The prices actually received ranged from $10.98 to $11.34. The reporting person will provide to the Issuer, any security holder of the Issuer, or the SEC staff, upon request, information regarding the number of shares purchased at each price within the range.

F5: On June 16, 2016, Longwood Fund III purchased 2,900 Common Shares. Following such purchase, Longwood Fund III owned 501,197 Common Shares and Longwood Fund II owned 2,697,264 Common Shares.