X0306 4 2017-05-16 0 0001481512 Ra Pharmaceuticals, Inc. RARX 0001297709 Novartis Bioventures Ltd C/O NOVARTIS INTERNATIONAL AG WSJ-200.220 BASEL V8 CH-4002 SWITZERLAND 0 0 1 0 0001114448 NOVARTIS AG LICHTSTRASSE 35 BASEL V8 4056 SWITZERLAND 0 0 1 0 Common Stock 2017-05-16 4 S 0 20081 26.3296 D 2440956 D Common Stock 2017-05-17 4 S 0 22534 25.5126 D 2418422 D Reflects sales of ordinary shares executed in multiple transactions at prices ranging from $25.45 to $26.73 on May 16, 2017 and $25.00 to $26.73 on May 17, 2017. The prices reported reflect the weighted average sale prices. The Reporting Persons hereby undertake to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the sales were effected. The board of directors of Novartis Bioventures Ltd. has sole voting and investment control and power over such securities. None of the members of its board of directors has individual voting or investment power with respect to such securities and each disclaims beneficial ownership of such securities. Novartis Bioventures Ltd. is an indirectly owned subsidiary of Novartis AG. /s/ Simon Zivi, Authorized Signatory /s/ Laurieann Chaikowsky, Authorized Signatory 2017-05-18 /s/ Simon Zivi, Authorized Signatory /s/ Laurieann Chaikowsky, Authorized Signatory 2017-05-18