Expanded access, also known as “compassionate use,” is a potential pathway that allows patients with serious or immediately life-threatening diseases or conditions to have access to an investigational drug for treatment outside of clinical trials when no comparable or satisfactory alternative therapy options are available. The following is Theseus Pharmaceuticals’ current expanded access policy for evaluating and responding to requests for expanded access to its investigational drugs for individual patients for serious diseases in accordance with section 561A of the Federal Food, Drug, and Cosmetic Act:

Theseus Pharmaceuticals is committed to studying and developing our investigational drug candidates as part of clinical trials designed to generate adequate safety and efficacy data in a comprehensive fashion that may then be used to support regulatory approval of the investigational drugs. This process of clinical trials and regulatory review and approval is intended to ultimately make our therapies more widely available to patients. Theseus Pharmaceuticals encourages patients to speak with their treating physicians about potential treatment options and, when appropriate, participate in clinical trials.

We understand that, in certain circumstances, patients may not meet the eligibility criteria to participate in a clinical trial and may have exhausted all available treatment options. Currently, however, Theseus Pharmaceuticals does not have an expanded access program that allows patients to have access to our investigational drug candidates outside enrollment in our clinical trials anywhere in the world. We encourage you to stay informed regarding our development programs. As more information on the clinical safety and efficacy of our investigational drug candidates become available, our policy on expanded access will be reviewed and updated. We may establish different expanded access polices for each investigational drug product.

If you have any questions regarding this policy, please contact Theseus Pharmaceuticals at [email protected]. Theseus plans to respond to expanded access inquiries within seven (7) business days of receipt.

As authorized by the 21st Century Cures Act, Theseus Pharmaceuticals may revise this expanded access policy at any time. The availability of this policy or any revised version shall not serve as a guarantee of access to any of our investigational drugs by any individual patient.

September 15, 2021