A Study to Learn How Safe AZD6621 is, How Well it Works, and How it Moves Throughout the Body Over Time, in Adult Male Participants With Metastatic Prostate Cancer

Exclusion Criteria

• •1. Any evidence of diseases (such as severe or uncontrolled systemic diseases) which in the Investigator's opinion makes it undesirable for the participant to participate in the study.
• •2. One or more of the following:
• •1. Mean resting corrected QT interval \> 470 ms,
• •2. History of QT prolongation associated with other medications that required discontinuation of that medication, or any current concomitant medication known to prolong the QT interval and cause Torsades de Pointes.
• •3. Congenital long QT syndrome, family history of long QT syndrome, or unexplained sudden death under 40 years of age in first degree relatives.
• •4. Inadequate cardiac function of LVEF \< 50% on screening cardiac MUGA or ECHO.
• •3. Cardiac arrhythmias (such as multifocal premature ventricular contractions, bigeminy, trigeminy, ventricular tachycardia), which are symptomatic or require treatment unless controlled by pacemaker; symptomatic or uncontrolled atrial fibrillation despite treatment, or asymptomatic sustained ventricular tachycardia.
• •4. History of another primary malignancy except for malignancy treated with curative intent with no known active disease (≥ 2 years) before the first dose of study intervention and of low potential risk for recurrence.
• •5. History of, or planned organ or allogeneic stem cell transplantation.
• •6. Unresolved toxicity from prior anti-cancer therapy of CTCAE Grade ≥ 2 (exceptions listed in protocol).
• •7. History of Grade ≥ 3 CRS or Grade ≥ 2 ICANS based on ASTCT criteria with prior therapy. CRS must be resolved prior to screening.
• •8. Previous history of hemophagocytic lymphohistiocytosis/ macrophage activation syndrome.
• •9. Active or prior documented autoimmune or inflammatory disorders (examples in protocol) within the past 3 years prior to the start of treatment or requiring permanent immunosuppressive therapy.
• •10. Spinal cord compression unless asymptomatic and treated and stable and not requiring continuous corticosteroids at a dose of \> 10 mg prednisone/day or equivalent.
• •11. CNS pathology (examples in protocol).
• •12. Active or uncontrolled hepatitis B or C virus infection (exceptions listed in the protocol).
• •13. Known HIV infection that is not well controlled (definition for HIV infection that is well controlled is listed in protocol).
• •14. Radiation therapy within 4 weeks of first dose of study intervention (or local or focal radiotherapy within 2 weeks of first dose).
• •15. Prior anti-cancer drug exposure requirement as stated in study protocol
• •16. Previous anti-cancer treatment requirements as stated in study protocol
• •17. Systemic corticosteroids at doses exceeding 10 mg/day of prednisone or equivalent \< 7 days prior to first dose.
• •18. Major surgical procedure or significant traumatic injury within 4 weeks prior to first dose.
• •19. Receipt of the last dose of anti-cancer therapy or participation in another clinical study with last dose administered in the last 21 days or 5 half-lives, whichever is shorter
• •\- CAR-T cell therapy within the last 6 months prior to enrolment on this study.
• •20. Participants with a known hypersensitivity to AZD6621 or any of its excipients.
• •21. Involvement in the planning and/or conduct of the study.
• •22. Participant is unlikely to comply with study procedures, restrictions, and requirements (as judged by the Investigator).
• •23. Receipt of live attenuated vaccine within 30 days prior to the first dose of study intervention or receipt of COVID-19 vaccination within 72 hours prior to the first dose of study intervention.
• •24. Previous enrolment in the present study.