X0306 4 2019-07-17 0 0001481512 Ra Pharmaceuticals, Inc. RARX 0001688199 Read Simon C/O RA PHARMACEUTICALS, INC. 87 CAMBRIDGEPARK DRIVE CAMBRIDGE MA 02140 0 1 0 0 Chief Scientific Officer COMMON STOCK 2019-07-17 4 M 0 10000 2.87 A 16234 D COMMON STOCK 2019-07-17 4 S 0 10000 32.9479 D 6234 D Stock Options (Right to buy) 2.87 2019-07-17 4 M 0 10000 0 D 2026-06-16 Common Stock 10000 96142 D The sale reported in the Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 16, 2019. The price reported is a weighted average price. The shares were sold in multiple transactions at per share prices ranging from $32.57 to $33.43. The Reporting Person undertakes to provide upon request to the SEC staff, the Issuer, or any stockholder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. These stock options vest over four (4) years beginning on April 4, 2016, at a rate of twenty-five percent (25%) after 12 months, and in thirty-six (36) equal monthly installments thereafter. /s/ David Lubner, Attorney-in-Fact for Simon Read 2019-07-18