This is a phase I single-arm clinical study conducted by West China Hospital of Sichuan University. The research duration is from October 2025 to June 2027, aiming to evaluate the safety and efficacy of vitamin B6-restricted (-VitB6 diet) in patients with solid tumors. A total of 20 patients with solid tumors, aged 18 - 75 years old, who meet specific inclusion criteria such as having at least one measurable lesion according to RECIST v1.1 criteria and an ECOG score of 0 - 1, will be enrolled.
Patients will receive -VitB6 diet intervention for 2 cycles (3 weeks per cycle) while continuing their original immunotherapy. The -VitB6 diet strictly limits vitamin B6 intake, and patients can only consume foods with extremely low vitamin B6 content. The research will collect data on patients' basic information, nutritional status, blood, immunity, and tumor imaging at baseline and during follow - up.
The primary endpoint of the study is the occurrence type, frequency, and severity of treatment-related adverse events (TEAE). Secondary endpoints include objective response rate (ORR), disease control rate (DCR), and duration of response (DoR). Exploratory endpoints involve evaluating the nutritional adequacy of the -VitB6 diet, its impact on patients' quality of life, and its influence on amino acid metabolism and immune status in patients.
During the study, safety will be evaluated by closely monitoring adverse events according to NCI CTCAE (version 5.0), and efficacy will be assessed using RECIST 1.1 standard. Statistical analysis will be performed using SAS 9.4 software, including descriptive statistics for safety and efficacy data, and calculating confidence intervals for relevant indicators. This study hopes to provide new strategies and directions for the treatment of advanced solid tumors.