A Phase I/IIa Study of C5252 in Patients With Intracranial Tumor

Key Inclusion Criteria: * Age ≥ 18 years. * Confirmed recurrent malignant high-grade (WHO grade 3-4) glioma who have received standard therapy and no available treatment. * Measurable lesions exist in accordance with RANO criteria. * Sufficient space for ≥1 mL drug infused into tumor cavity post resection. * Ommaya reservoir has been placed in the operation area, and drug administration conditions are available. * Karnofsky Performance Status (KPS) ≥ 60% * Life expectancy \> 12 weeks. * No severe hematological, cardiovascular, liver or kidney diseases. * If the patient is a sexually active female of childbearing potential or if the patient is a sexually active male whose partner is a female of childbearing potential, the patient must use appropriate contraceptive measures for the duration of the treatment and for 6 months afterwards. Female patients of childbearing potential must have a negative serum pregnancy test within 7 days of before the C5252 infusion. * Capable of understanding and complying with protocol requirements. Key Exclusion Criteria: * Inability to undergo MRI examination for any reason. * Active hemorrhage observed before enrollment. * Imaging test: a. lesion located in non-cerebral regions; b. there are other lesions outside target tumor cavity; c. extra-cranial metastasis. * Tumor lesion locates in ventricular system or there is a clear perforation between the tumor cavity and the ventricle after tumor resection. * History of encephalitis, multiple sclerosis or other central nervous system infections * Treated with steroid hormones and/or more than 5 mg dexamethasone per day or other immunosuppressive drugs for systemic treatment within 4 weeks. * Persistent or active infection, and cannot be controlled by treatment. * Subjects with bleeding tendency or need to take anticoagulant drugs, antiplatelet drugs or non-steroidal anti-inflammatory drugs (NSAIDs) and are unable to discontinue. * Uncontrolled disease, including but not limited to symptomatic congestive heart failure, unstable angina pectoris. * Other malignant tumor within 5 years. * Patients who require an attenuated or live vaccine within 28 days prior to the first trial drug administration and during the study treatment period. * In the period of recurrent herpes simplex virus infection, with corresponding clinical manifestations. * Systemic use (other than topical) of anti-HSV drugs * Prior treatment with any oncolytic virus, cell therapy or gene therapy. * Participants have a history of splenectomy, organ transplantation, bone marrow transplantation or stem cell transplantation * Prior antitumor treatment with intracranial implants, such as Carmustine. * Previous history of allergic reactions to similar biological components such as HSV-1, IL-12 or anti-PD-1 antibodies, or with known allergic reactions to any component of the C5252 prescription, including glycerol. * Developed ≥Grade 3 irAE during previous immunotherapy * History of frequent drug use (including "recreational use") or drug abuse (including alcohol abuse) within one year prior to signing the informed consent form. * Other situation that PI consider subjects not appropriate to participate in the study.