Investor Relations Captor Therapeutics ®

Information on research and development progress in the CT-03 project

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Current Report No. 57/2023

Date of preparation: 6 December 2023.

Subject: Information on research and development progress in the CT-03 project.

Legal basis: Article 17 (1) MAR - confidential information.

The Management Board of Captor Therapeutics S.A., with its registered office in Wroclaw (the "Company"), informs about progress in preclinical study with its project CT-03, dedicated to the development of cancer therapies based on targeted protein degradation. The first-in-class molecules inducing the degradation of the MCL-1 protein developed by Captor may be used in the treatment of a number of hematological malignancies, lung cancer and triple negative breast cancer - cancers with very large and unmet market needs.

An independent and renowned subcontractor conducted a pharmacokinetic / pharmacodynamic (PKPD) study based on a single intravenous administration of both compounds of CT-03 project to Macaca fascicularis monkeys. The concentration of the compound and the level of degradation of the molecular target in peripheral blood cells were determined in the collected blood samples, demonstrating complete degradation of the MCL-1 protein. The level of troponin, which is  biomarker of myocardial damage, was also determined. The level of troponin in blood samples taken from subjects administered with the two CT-03 compounds did not change, in contrast to samples taken from subjects treated with a control drug known to cause  heart damage, which gave a significant increase in the level of troponin. According to the Company these results, indicate the lack of potential side effects from the CT-03 drugs related to cardiotoxicity  and thus could allow the realization of the great therapeutic potential of drugs targeting MCL-1 which has so far been unrealised using inhibitors. It should be emphasized that the level of degradation of MCL-1 protein in peripheral blood cells taken from humans is practically the same as the level of degradation in the same cells taken from monkeys after treatment with the two CT-03 degraders. This emphasizes the relevance of the results and strengthens the safety of the degraders for administration to patients Cardiotoxicity is a side effect of inhibiting MCL-1 protein activity with traditional inhibitor drugs and has resulted in the discontinuation of several clinical trials.

In the opinion of the Company's Management Board, the above information represents significant research and development progress on the CT-03 project and was therefore considered inside information.