Neoantigen Peptide Vaccine Plus Pembrolizumab in Renal Cell Carcinoma

This is a Phase I, single-center, open-label, single-arm clinical trial to evaluate the safety and efficacy of personalized neoantigen polyepitope peptide vaccine combined with pembrolizumab in patients with advanced, recurrent or refractory renal cell carcinoma (RCC).

Background: Renal cell carcinoma is one of the most common malignancies of the urinary system. Although pembrolizumab has become a standard first-line treatment, the objective response rate (ORR) of monotherapy is only 20-40%, and most patients eventually develop primary or acquired resistance. Tumor neoantigens are specific antigens produced by tumor-specific gene mutations, with high immunogenicity and tumor specificity, making them ideal targets for tumor immunotherapy. Preliminary clinical studies have shown that neoantigen vaccines can produce synergistic effects when combined with pembrolizumab.

Study Design: This is an investigator-initiated trial (IIT) conducted at Peking University First Hospital. The study will enroll 5-8 patients in two stages: an initial safety assessment cohort (3 patients) followed by an expansion cohort (5 additional patients) if safety criteria are met. The study drug is a personalized neoantigen polyepitope peptide vaccine (Neo-RCC), produced by Mingzhibenyuan Medical Technology (Beijing) Co., Ltd., based on whole exome sequencing (WES) and transcriptome sequencing (RNA-seq) of each patient's tumor tissue. The vaccine is administered via subcutaneous injection in combination with Polyinosinic-polycytidylic acid stabilized with poly-L-lysine and carboxymethylcellulose (Poly-ICLC) adjuvant, with a priming phase (5 injections on Days 0, 3, 7, 14, 21) and a boosting phase (3 injections on Weeks 6, 12, and 20), totaling 8 injections. Pembrolizumab (200 mg intravenous \[IV\] every 3 weeks \[Q3W\]) is administered concurrently as combination therapy.

Primary Objective: To evaluate the safety of the personalized neoantigen peptide vaccine in advanced RCC patients, as measured by the incidence and severity of treatment-emergent adverse events (TEAE) graded by National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v5.0.

Secondary Objectives: To evaluate pharmacokinetic characteristics; to assess efficacy including objective response rate (ORR), duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1.

Key Eligibility Criteria: Adults (≥18 years) with Stage III or IV, locally advanced, recurrent or metastatic non-surgical RCC who have achieved disease stability for ≥3 months after prior targeted therapy combined with pembrolizumab; measurable disease per RECIST v1.1; Eastern Cooperative Oncology Group (ECOG) performance status 0-3; adequate organ function; and ≥50 tumor gene mutations detectable from biopsy tissue.

Safety Monitoring: A Data Safety Monitoring Board (DSMB) will oversee patient safety. Dose-limiting toxicities (DLT) are defined according to protocol-specified criteria. If ≥2 DLTs occur in the initial cohort, the adjuvant dose will be reduced by 50% and the study will proceed with a de-escalation cohort.