| Date | Name | Symbol | Type | Security | Shares | Price | Value | Ownership | Reported |
| 08/17/2023 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 1.9k | $1.18 | $2.3k | | 08/16/2023 |
| 08/16/2023 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted Stock Unit | 6.2k | $0.00 | $0 | | 08/16/2023 |
| 01/17/2023 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 458 | $5.74 | $2.6k | | 01/13/2023 |
| 01/14/2023 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted stock unit | 1.5k | $0.00 | $0 | | 01/13/2023 |
| 01/13/2023 | Mersana Therapeutics, Inc. | MRSN | Grant | Stock option (right to buy) | 127.5k | $6.06 | $772.6k | | 01/13/2023 |
| 01/13/2023 | Mersana Therapeutics, Inc. | MRSN | Grant | Restricted stock unit | 28.3k | $0.00 | $0 | | 01/13/2023 |
| 08/17/2022 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 1.9k | $7.10 | $13.3k | | 08/16/2022 |
| 08/16/2022 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted stock unit | 6.2k | $0.00 | $0 | | 08/16/2022 |
| 01/14/2022 | Mersana Therapeutics, Inc. | MRSN | Grant | Stock Option (right to buy) | 26.2k | $6.28 | $164.8k | | 01/14/2022 |
| 01/14/2022 | Mersana Therapeutics, Inc. | MRSN | Grant | Restricted Stock Units | 5.8k | $0.00 | $0 | | 01/14/2022 |