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Merger with Sesen Bio - Schedule of Net Assets Acquired in the Merger (Details) $ in Thousands | 7 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2023 USD ($) seat shares | Mar. 07, 2023 USD ($) shares | Dec. 31, 2022 shares
Merger with Sesen Bio |  |  |
Number of board seats | seat | 7 |  |
Entity common stock, shares outstanding immediately after merger | shares | 40,304,436 |  | 2,217,737
Cash and cash equivalents |  | $ 37,873 |
Marketable securities |  | 44,588 |
Prepaid expenses and other assets |  | 1,316 |
Restricted cash |  | 30 |
Accounts payable and accrued expenses |  | (3,499) |
Total net assets acquired |  | 80,308 |
Less: Transaction costs |  | (8,264) |
Total net assets acquired less transaction costs |  | $ 72,044 |
Carisma Therapeutics Inc. |  |  |
Merger with Sesen Bio |  |  |
Severance and personnel costs paid | $ 4,600 |  |
CARISMA Therapeutics Inc, Legacy, Stockholders | Carisma Therapeutics Inc. |  |  |
Merger with Sesen Bio |  |  |
Business acquisition percentage of voting interests acquired |  | 74.20% |
Entity common stock, shares outstanding immediately after merger | shares |  | 40,254,666 |

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