| Date | Name | Symbol | Type | Security | Shares | Price | Value | Ownership | Reported |
| 01/17/2023 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 2.2k | $5.74 | $12.7k | | 01/13/2023 |
| 01/14/2023 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted stock unit | 7.1k | $0.00 | $0 | | 01/13/2023 |
| 01/13/2023 | Mersana Therapeutics, Inc. | MRSN | Grant | Stock option (right to buy) | 217.5k | $6.06 | $1.3M | | 01/13/2023 |
| 01/13/2023 | Mersana Therapeutics, Inc. | MRSN | Grant | Restricted stock unit | 48.3k | $0.00 | $0 | | 01/13/2023 |
| 12/01/2022 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 5.5k | $6.59 | $36.4k | | 11/30/2022 |
| 11/30/2022 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted stock unit | 18.5k | $0.00 | $0 | | 11/30/2022 |
| 01/14/2022 | Mersana Therapeutics, Inc. | MRSN | Grant | Stock Option (right to buy) | 127.5k | $6.28 | $800.7k | | 01/14/2022 |
| 01/14/2022 | Mersana Therapeutics, Inc. | MRSN | Grant | Restricted Stock Units | 28.3k | $0.00 | $0 | | 01/14/2022 |
| 12/01/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 5.5k | $6.81 | $37.6k | | 11/30/2021 |
| 11/30/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted Stock Units | 18.5k | $0.00 | $0 | | 11/30/2021 |
| 11/30/2020 | Mersana Therapeutics, Inc. | MRSN | Grant | Stock Option (right to buy) | 200k | $25.48 | $5.1M | | 11/30/2020 |
| 11/30/2020 | Mersana Therapeutics, Inc. | MRSN | Grant | Restricted stock unit | 37k | $0.00 | $0 | | 11/30/2020 |