Phase I Study of Irinotecan Dose Adjustment Guided by UGT1A1*6 Genotype in VIT Regimen for the Treatment of Relapsed and Refractory Childhood Solid Tumors
Irinotecan is a commonly used salvage chemotherapy drug for children with relapsed and refractory solid tumors. Common dose-limiting toxicities of irinotecan include abdominal pain and diarrhea. Studies have shown that patients with UGT1A16 gene mutations have a higher incidence of these side effects, thereby limiting the dosage of irinotecan. The combination of irinotecan with temozolomide and vincristine is a common salvage chemotherapy regimen for children with relapsed and refractory solid tumors. Currently, the recommended dose of irinotecan is 50mg/m², but there is still significant room for improvement in the efficacy of VIT for these children. Whether patients with wild-type UGT1A16 can further increase the dosage of irinotecan, thereby enhancing the efficacy of the VIT regimen, is the focus of our research.
• Age \< 18 years.
• Relapsed and refractory childhood solid tumors (pathologically confirmed). Definition of relapsed and refractory patients: 1. Patients who fail to achieve GPR or CR after first-line treatment are defined as refractory; 2. Patients who achieve CR after first-line treatment but relapse after more than 1 month are defined as relapsed.
• Must have undergone UGT1A1\*6 genotype testing (provided free of charge by Jiangsu Hengrui Medicine Co., Ltd.), with results being wild type (T/T).
• Patients must be at least 3 weeks post the last myelosuppressive chemotherapy and at least 6 months post hematopoietic stem cell transplantation, 2 weeks post local radiotherapy, 6 months post craniospinal or extensive pelvic radiotherapy, or 6 weeks post extensive bone marrow radiotherapy.
• Must have at least one measurable lesion as defined by RECIST criteria;
• Karnofsky score (for ages \> 10, see Annex I) or Lansky score (for ages ≤ 10, see Annex II) ≥ 50 points;
• Expected survival time ≥ 6 months;
• Patients must have fully recovered from all acute toxic effects of previous anticancer chemotherapy: a) Bone marrow suppression chemotherapy: at least 21 days post the last bone marrow suppressive chemotherapy; b) Hematopoietic growth factors: at least 14 days post the last dose of long-acting growth factor or 7 days post the last dose of short-acting growth factor;
• For patients known not to involve the BM: a) Absolute neutrophil count (ANC) ≥ 1.0×10⁹/L; b) Non-transfused platelet count ≥ 100.0×10⁹/L; c) Hemoglobin ≥ 80 g/L;
⁃ Liver and kidney functions must meet the following criteria: a) Total bilirubin (conjugated + unconjugated) ≤ 1.5× upper limit of normal (ULN) for age; b) Aspartate aminotransferase (AST) ≤ 2.5×ULN (≤ 110 U/L); c) Glomerular filtration rate or creatinine clearance ≥ 70 mL/min/1.73 m² or corresponding age-normal serum creatinine; d) Serum albumin ≥ 20 g/L.
⁃ Capable of adhering to outpatient treatment, laboratory monitoring, and necessary clinical visits during the study period;
⁃ Parents/guardians of children or adolescent subjects must be able to understand, consent to, and sign the informed consent form (ICF) and applicable child consent forms before initiating any protocol-related procedures; if parents/guardians agree, subjects must be capable of expressing consent (when applicable).