Clinical Trial to Evaluate the Safety, Tolerability and Efficacy of CT303 in Patients With Psoriasis

Inclusion Criteria: 1. ≥ 19 years old 2. Plaque psoriasis diagnosed before ≥ 6 months who did not show a sufficient response to one or more of the traditional systemic treatments or require change of treatment due to intolerance 3. Have moderate to severe plaque psoriasis as defined by PASI score ≥ 12, BSA ≥ 10% and sPGA score ≥ 3 4. Patients who have voluntarily decided to participate in the study and signed the informed consent form Exclusion Criteria: 1. Guttate psoriasis, erythrodermic psoriasis, palmoplantar psoriasis, drug-induced psoriasis, and inverse psoriasis 2. History of treatment with cell therapy products including but not limited to mesenchymal stem cells 3. Have hypersensitivity, or medical history of clinically significant hypersensitivity, to the IP or its excipients 4. Current or history of cardiovascular diseases 5. Clinically significant hemorrhagic diseases, or gastrointestinal, respiratory, endocrinal, musculoskeletal, or neuropsychiatric disorders that are deemed by the investigator to be a potential threat to the safety of the subject due to study participation 6. Use of anticoagulants within 7 days prior to IP administration 7. Following treatment history for psoriasis * Use of topical therapy within the past 2 weeks * Use of phototherapy and/or systemic therapy within the past 4 weeks * Use of biologics within the past 4 to 24 weeks 8. Severe infection or other uncontrolled active infectious diseases requiring administration of systemic antibiotics, antivirals, etc. within 4 weeks prior to IP administration 9. Systemic or local inflammatory diseases requiring systemic anti-inflammatory treatment within 4 weeks prior to IP administration 10. Received or are scheduled to receive a live/live attenuated viral/bacterial vaccination within 12 weeks prior to IP administration (within 12 months for BCG vaccines) 11. Require administration of any prohibited concomitant medication specified in this protocol during participation in the study 12. QTc interval \> 480 msec 13. Any of the following abnormalities or abnormal findings from laboratory tests: * AST or ALT \> 3 times the upper limit of normal * Serum creatinine \> 1.5 times the upper limit of normal * ANC \< 1,500/μL, Hemoglobin \< 10 g/dL, Platelet count \< 100,000/μL 14. Hepatitis B or C infection or positive test for HIV at screening 15. History of malignant tumors within the last 5 years prior 16. Received or used any other IP or investigational device within 4 weeks prior to IP administration 17. Pregnant or breast-feeding women, or women of childbearing potential and men who do not agree to abstinence or use of effective methods of contraception from the time of obtaining informed consent and during the study 18. Patients who are deemed ineligible to participate in the study for other reasons by the investigator