Risk Factors Update Summary

• Added details on royalty payments on net sales of products developed from collaboration with Amgen.
• Lease expiration extended from October 2024 to October 2029, impacting long-term facility commitments.
• Business now depends on proprietary platform success. Limited operating history poses evaluation challenges.
• TSC-204 changed to TSC-203-A0201 for targeting melanoma associated antigen 1.
• Limited experience in clinical trials and manufacturing poses challenges in product development.
• Approximately 100 novel antigens increased to approximately 200 as targets for tumor infiltrating T cells.
• Manufacturing enhancements, including CD8α/β and DN-TGFβRII, aim to improve TCR-T therapy responses.
• Added manufacturing capacity at Waltham, Massachusetts, with potential $70 million investment.
• Expanded target discovery efforts into T-cell mediated autoimmune disorders from diseases.
• Two initial TCR-T product candidates increased to six for IND applications.
• TSC-200 series changed to TSC-20X for TCR-T candidates in clinical development.
• The threshold for an affirmative vote of holders increased to at least 66% of the voting power.
• The number of full-time employees increased from 137 to 154, and part-time employees decreased from 1 to 0.
• Increase in full-time employees from 137 to 154 and part-time employees from 1 to 0.
• Risks related to adverse financial industry events could impact business operations and financial condition.
• Revenue solely from product sales. Failure to raise capital may delay product development.
• Initial safety data expected in first half of 2024, with multiplex therapy data in 2025.
• Federal research and development tax credit carryforwards increased from $6 million to $11 million.
• Net losses increased significantly from $26 million in 2020 to $89 million in 2023.
• Federal net operating loss carryforwards decreased from $86 million to $84 million.
• Enhanced TCR-T therapy development by advancing seven IND applications for solid tumor programs.
• Ownership by executive officers, directors, and entities increased to approximately 32% of outstanding voting stock and 38% of outstanding common stock.
• Rising inflation rates may increase operating costs, reduce liquidity, and impact credit access.
• Expansion of ImmunoBank to include diverse TCRs for solid tumors aims to overcome resistance mechanisms.
• FDA cleared IND application for T-Plex, serving as primary IND application for solid tumor program.
• Global economic uncertainty may impact liquidity and growth opportunities, affecting market competitiveness.
• Enrolling patients in screening protocol moved from middle to first quarter of 2023.
• Expenses for research and development in the U.S. will be capitalized and amortized post-2021.
• Increased inflation may affect operating costs, liquidity, and access to debt and equity capital.