Evaluation of the Effect of Cordycepin on CD8+ Lymphocytopenia in Patients With Solid Tumors

The goal of this clinical trial is to evaluate the effectiveness of PRaG-1 in improving CD8+ lymphocytopenia in patients with solid tumors who are tumor-free for more than six months after completing radiotherapy and/or chemotherapy. It will also assess the safety of PRaG-1 Cordycepin in these patients. The main questions it aims to answer are: Does PRaG-1 increase CD8+ lymphocyte counts by more than 25% in this patient population? Does the effect of PRaG-1 maintain when treatment is discontinued? What are the safety and tolerability profiles of PRaG-1 during and after the treatment period? Participants will receive open-label PRaG-1 (one tablet in the morning and one in the evening) for 14 days, and those who show a response (CD8+ lymphocytes increase by more than 25%) will enter a 14-day randomized withdrawal period, where they will be assigned to continue PRaG-1 or switch to a placebo. Throughout the study, participants will: Have their peripheral blood lymphocyte subpopulations tested at baseline and on Days 7 and 14 Undergo safety monitoring for adverse events according to CTCAE 5.0 criteria Provide information on their quality of life during the treatment period Researchers will compare the outcomes of those who continue PRaG-1 to those who receive a placebo to determine if the observed improvement in CD8+ lymphocytes is sustained, which would indicate that the drug is effective in maintaining immune response.