EXHIBIT 99.1
AGREEMENT
In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree that this Statement on Schedule 13G relating to the Common Stock of Rhythm Pharmaceuticals, Inc. is being filed with the Securities and Exchange Commission on behalf of each of them.
February 13, 2018
| BAKER BROS. ADVISORS LP | ||
| By: | Baker Bros. Advisors (GP) LLC, its general partner | |
| By: | /s/ Scott L. Lessing | |
| Name: Scott L. Lessing Title: President | ||
| BAKER BROS. ADVISORS (GP) LLC | ||
| By: | /s/ Scott L. Lessing | |
| Name: Scott L. Lessing Title: President | ||
| /s/ Julian C. Baker | ||
| Julian C. Baker | ||
| /s/ Felix J. Baker | ||
| Felix J. Baker | ||