| 6.28% | % of Shares Held by All Insider |
| 0.00% | % of Shares Held by Institutions |
| 0.00% | % of Float Held by Institutions |
| 0 | Number of Institutions Holding Shares |
| Holder | Shares | Date Reported | % Out | Value |
|---|---|---|---|---|
| TRV GP III, LLC | 6,391,176 | Dec 30, 2018 | 19.59% | 60,077,054 |
| BB Biotech Ag | 2,865,841 | Dec 30, 2018 | 8.79% | 26,938,905 |
| Armistice Capital, LLC | 2,836,000 | Dec 30, 2018 | 8.69% | 26,658,400 |
| Blackrock Inc. | 1,859,018 | Dec 30, 2018 | 5.70% | 17,474,769 |
| Vanguard Group, Inc. (The) | 1,383,760 | Dec 30, 2018 | 4.24% | 13,007,344 |
| Highline Capital Management, L.P. | 1,284,697 | Dec 30, 2018 | 3.94% | 12,076,151 |
| Casdin Capital, LLC | 1,128,075 | Dec 30, 2018 | 3.46% | 10,603,905 |
| FMR, LLC | 911,062 | Dec 30, 2018 | 2.79% | 8,563,982 |
| Farallon Capital Management LLC | 909,158 | Dec 30, 2018 | 2.79% | 8,546,085 |
| Wellington Management Company, LLP | 492,196 | Dec 30, 2018 | 1.51% | 4,626,642 |
| Holder | Shares | Date Reported | % Out | Value |
|---|---|---|---|---|
| Fidelity Select Portfolios - Biotechnology | 738,062 | Feb 27, 2019 | 2.26% | 11,070,930 |
| Mutual Fund Ser Tr-Eventide Healthcare & Life Sciences Fund | 703,425 | Jun 29, 2018 | 2.16% | 13,744,924 |
| Vanguard Total Stock Market Index Fund | 614,373 | Sep 29, 2018 | 1.88% | 11,623,937 |
| iShares Russell 2000 ETF | 445,836 | Feb 27, 2019 | 1.37% | 6,687,540 |
| iShares NASDAQ Biotechnology ETF | 355,981 | Feb 27, 2019 | 1.09% | 5,339,715 |
| Vanguard Extended Market Index Fund | 284,963 | Sep 29, 2018 | 0.87% | 5,391,499 |
| iShares Russell 2000 Growth ETF | 184,152 | Feb 27, 2019 | 0.56% | 2,762,280 |
| JP Morgan U.S. Small Company Fund | 170,900 | Feb 27, 2019 | 0.52% | 2,563,500 |
| Advanced Series Tr-AST Small Cap Growth Port | 152,147 | Sep 29, 2018 | 0.47% | 2,878,621 |
| Fidelity Extended Market Index Fund | 103,663 | Feb 27, 2019 | 0.32% | 1,554,945 |