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.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

1. Histologically or cytologically confirmed Stage III or IV, locally advanced, recurrent or metastatic renal cell carcinoma (RCC) not amenable to curative surgery
2. Disease stability for ≥3 months after prior single pembrolizumab therapy, with documented progression or intolerance to standard treatment
3. At least one measurable lesion per RECIST v1.1 (longest diameter ≥10 mm for non-lymph node lesions; short axis ≥15 mm for lymph nodes; or bone lesions confirmed by CT/MRI)
4. Age ≥18 years
5. Estimated life expectancy ≥3 months
6. ECOG performance status 0-3
7. Availability of tumor tissue (biopsy or archival specimen) for whole exome sequencing (WES) and RNA sequencing (RNA-seq), with ≥50 tumor gene mutations detectable
8. Adequate organ function as defined by laboratory parameters within 14 days prior to enrollment:

   8.1 Hematologic: Absolute Neutrophil Count(ANC) ≥1.5×10⁹/L, platelet count ≥100×10⁹/L, hemoglobin ≥90 g/L; 8.2 Hepatic: total bilirubin(TBIL) ≤1.5×Upper Limit of Normal(ULN), Aspartate Aminotransferase(AST)/Alanine Aminotransferase(ALT) ≤2.5×ULN (≤5×ULN if liver metastases present); 8.3 Renal: serum creatinine ≤1.5×ULN or creatinine clearance ≥50 mL/min (Cockcroft-Gault formula); 8.4 Coagulation: international normalized ratio(INR) ≤1.5, activated partial thromboplastin time(APTT) ≤1.5×ULN; 8.5 Cardiac: Left Ventricular Ejection Fractions(LVEF) ≥50% by echocardiography;
9. Ability to comply with study procedures and follow-up schedule;
10. Signed informed consent form;
11. For women of childbearing potential: negative serum pregnancy test (Human Chorionic Gonadotropin sensitivity ≤25 IU/L) within 7 days prior to enrollment; agreement to use effective contraception during study and for 4 weeks after last dose;
12. For men: agreement to use effective contraception during study and for 4 weeks after last dose.

Exclusion Criteria:

1. Pregnant or lactating women
2. Prior treatment with:

   2.1 Two or more lines of immune checkpoint inhibitor (ICI) systemic therapy; 2.2 CTLA-4 inhibitor (e.g., ipilimumab); 2.3 Tumor vaccine therapy (including neoantigen vaccine, dendritic cell vaccine, etc.); 2.4 Chemotherapy specifically for renal cell carcinoma; 2.5 Allogeneic hematopoietic stem cell or solid organ transplantation;
3. Active autoimmune disease or other immune-mediated disorders requiring systemic immunosuppressive therapy;
4. Participation in another investigational drug study within 4 weeks prior to first dose;
5. Active infection including:

   5.1 Known Human Immunodeficiency Virus(HIV) infection; 5.2 Active hepatitis B (HBsAg positive and Hepatitis B Virus-DNA \>500 IU/mL) or hepatitis C (HCV-RNA positive); 5.3 Active tuberculosis (T-SPOT or PPD positive with clinical symptoms, or chest CT suggestive of active TB); 5.4 Severe infection requiring intravenous antibiotics within 2 weeks prior to enrollment, or uncontrolled systemic infection;
6. Symptomatic central nervous system (CNS) metastases; exception: patients with treated CNS metastases stable for ≥4 weeks without neurological symptoms and without corticosteroid requirement;
7. Uncontrolled comorbidities including:

   7.1 Symptomatic congestive heart failure (New York Heart Association Class III-IV); 7.2 Unstable angina or myocardial infarction within 6 months; 7.3 Uncontrolled arrhythmia; 7.4 Uncontrolled hypertension (systolic ≥160 mmHg or diastolic ≥100 mmHg despite standard treatment); 7.5 Active peptic ulcer or gastrointestinal bleeding; 7.6 Active interstitial lung disease or pulmonary fibrosis;
8. Other malignancy within 5 years (except cured cervical carcinoma in situ, basal cell carcinoma, or squamous cell skin carcinoma);
9. Live vaccine administration within 4 weeks prior to enrollment or planned during study (inactivated vaccines allowed);
10. Known hypersensitivity to peptide vaccine components, adjuvants (e.g., Montanide ISA-51, Poly-ICLC), or pembrolizumab;
11. Sarcomatoid or rhabdoid RCC as predominant histology (mixed histology allowed if non-pure sarcomatoid/rhabdoid);
12. Any condition that, in the investigator's opinion, would compromise patient safety or compliance;
13. Any other condition that the investigator considers unsuitable for study participation.

• BACKGROUNDPlimack ER, Powles T, Stus V, Gafanov R, Nosov D, Waddell T, Alekseev B, Pouliot F, Melichar B, Soulieres D, Borchiellini D, McDermott RS, Vynnychenko I, Chang YH, Tamada S, Atkins MB, Li C, Perini R, Molife LR, Bedke J, Rini BI. Pembrolizumab Plus Axitinib Versus Sunitinib as First-line Treatment of Advanced Renal Cell Carcinoma: 43-month Follow-up of the Phase 3 KEYNOTE-426 Study. Eur Urol. 2023 Nov;84(5):449-454. doi: 10.1016/j.eururo.2023.06.006. Epub 2023 Jul 25. PMID 37500340
• BACKGROUNDTannir NM, Albiges L, McDermott DF, Burotto M, Choueiri TK, Hammers HJ, Barthelemy P, Plimack ER, Porta C, George S, Donskov F, Atkins MB, Gurney H, Kollmannsberger CK, Grimm MO, Barrios C, Tomita Y, Castellano D, Grunwald V, Rini BI, Jiang R, Desilva H, Fedorov V, Lee CW, Motzer RJ. Nivolumab plus ipilimumab versus sunitinib for first-line treatment of advanced renal cell carcinoma: extended 8-year follow-up results of efficacy and safety from the phase III CheckMate 214 trial. Ann Oncol. 2024 Nov;35(11):1026-1038. doi: 10.1016/j.annonc.2024.07.727. Epub 2024 Aug 2. PMID 39098455
• BACKGROUNDMotzer RJ, Escudier B, George S, Hammers HJ, Srinivas S, Tykodi SS, Sosman JA, Plimack ER, Procopio G, McDermott DF, Castellano D, Choueiri TK, Donskov F, Gurney H, Oudard S, Richardet M, Peltola K, Alva AS, Carducci M, Wagstaff J, Chevreau C, Fukasawa S, Tomita Y, Gauler TC, Kollmannsberger CK, Schutz FA, Larkin J, Cella D, McHenry MB, Saggi SS, Tannir NM. Nivolumab versus everolimus in patients with advanced renal cell carcinoma: Updated results with long-term follow-up of the randomized, open-label, phase 3 CheckMate 025 trial. Cancer. 2020 Sep 15;126(18):4156-4167. doi: 10.1002/cncr.33033. Epub 2020 Jul 16. PMID 32673417
• BACKGROUNDOtt PA, Hu-Lieskovan S, Chmielowski B, Govindan R, Naing A, Bhardwaj N, Margolin K, Awad MM, Hellmann MD, Lin JJ, Friedlander T, Bushway ME, Balogh KN, Sciuto TE, Kohler V, Turnbull SJ, Besada R, Curran RR, Trapp B, Scherer J, Poran A, Harjanto D, Barthelme D, Ting YS, Dong JZ, Ware Y, Huang Y, Huang Z, Wanamaker A, Cleary LD, Moles MA, Manson K, Greshock J, Khondker ZS, Fritsch E, Rooney MS, DeMario M, Gaynor RB, Srinivasan L. A Phase Ib Trial of Personalized Neoantigen Therapy Plus Anti-PD-1 in Patients with Advanced Melanoma, Non-small Cell Lung Cancer, or Bladder Cancer. Cell. 2020 Oct 15;183(2):347-362.e24. doi: 10.1016/j.cell.2020.08.053.