Neoantigen-based Personalized DNA Vaccine With Retifanlimab PD-1 Blockade Therapy in Patients With Newly Diagnosed, Unmethylated Glioblastoma

Step 1 Inclusion Criteria for Tissue Sequencing:

• Newly diagnosed histologically or molecularly consistent with WHO grade IV highgrade glioma, IDH wildtype.

• Patients who had prior craniotomy with biopsy, subtotal resection, total grossresection, or re-resection will be permitted.

• Consent to genome sequencing and dbGaP-based data sharing and has provided or willprovide germline (PBMC) and tumor DNA/RNA samples of adequate quality forsequencing. (Acquisition of specimens for sequencing and the sequencing itself maybe done as part of routine care or another research project.)

• At least 18 years of age.

• Ability to understand and willingness to sign an IRB approved written informedconsent document (or that of legally authorized representative, if applicable).

Step 2 Inclusion Criteria for Treatment Administration:

• Confirmed MGMT promoter unmethylated glioblastoma multiforme. Patients withsecondary glioblastoma, in particular those who are IDH1 or IDH2 mutant, will not beexcluded. High grade gliomas with molecular features of glioblastoma will beincluded. MGMT promoter methylation status must be determined by a standardPCR-based assay.

Note: While tissue sequencing can begin prior to confirmation of MGMT promotor status, the manufacturing process will not begin until MGMT promotor is confirmed as unmethylated.

• Personalized neoantigen DNA vaccine manufactured for administration.

• Karnofsky performance status ≥ 60%

• Normal bone marrow and organ function as defined below:

• Absolute neutrophil count ≥ 1,500/mcL

• Platelets ≥ 100,000/mcL

• Total bilirubin ≤ 1.5 x IULN

• AST(SGOT)/ALT(SGPT) ≤ 2.5 x IULN

• Creatinine ≤ IULN OR creatinine clearance ≥ 60 mL/min/1.73 m^2 for patientswith creatinine levels above institutional normal

• Systemic corticosteroid therapy is permitted provided dosing is no greater than 2 mgper day (dexamethasone or equivalent) on the day of vaccine administration.Participants using topical, ocular, intra-articular, or intranasal/inhaled steroidsmay participate. Brief courses of corticosteroids for prophylaxis (eg, contrast dyeallergy) or study treatment-related standard premedication are permitted.

• Bevacizumab will be allowed if given for symptomatic control of vasogenic edema andto avoid corticosteroid use.

• Women of childbearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control, abstinence) prior to study entry andfor the duration of study participation, including at least 5 months (for women ofchildbearing potential) and at least 7 months (for men) after last dose of studydrug. Should a woman become pregnant or suspect she is pregnant while participatingin this study, she must inform her treating physician immediately.

• Patients who require additional surgery prior to vaccination (craniotomy withbiopsy, subtotal resection, total gross resection, or laser interstitial thermaltherapy (LITT) laser ablation) will not be considered ineligible.

Step 2 Exclusion Criteria:

• As this study aims to assess the immunogenicity of a personalized neoantigen DNAvaccine in combination with checkpoint blockade, no prior immunotherapy will bepermitted.

• Inadequate tissue acquisition to allow for neoantigen screening.

• No candidate neoantigen identified during screening. ≤ 3 years previous with the exception of non-melanomaskin cancer, any in situ cancer that has been successfully resected and cured,treated superficial bladder cancer, or any early-stage solid tumor that wassuccessfully resected without need for adjuvant radiation or chemotherapy.

• Known allergy, or history of serious adverse reaction to, vaccines such asanaphylaxis, hives, or respiratory difficulty.

• A history of allergic reactions attributed to compounds of similar chemical orbiologic composition to any agents used in the study.

• History of immunodeficiency disorder or autoimmune condition requiring activeimmunosuppressive therapy. This includes inflammatory bowel disease, ulcerativecolitis, Crohn's disease, systemic vasculitis, scleroderma, psoriasis, multiplesclerosis, hemolytic anemia, immune-mediated thrombocytopenia, rheumatoid arthritis,systemic lupus erythematosus, Sjögren's syndrome, sarcoidosis, or otherrheumatologic disease or any other medical condition or use of medication whichmight make it difficult for the patient to complete the full course of treatments orto generate an immune response to vaccines.

• Presence of acute or chronic bleeding or clotting disorder that would contraindicateIM injections.

• Presence of a cardioverter-defibrillator or pacemaker (to prevent a life-threateningarrhythmia) that is located ipsilateral to the intended deltoid injection site (unless deemed acceptable by a Cardiologist).

• Presence of any metal implants or implantable medical device within theelectroporation area.

• Any active uncontrolled neurologic disorder, including seizures and epilepsy.

• Recurrent known vasovagal-related syncopal episodes resulting in loss ofconsciousness.

• Individuals in whom skin pinch thickness for all eligible injection sites exceeds 50mm.

• Individuals in whom the ability to observe possible local reactions at the eligibleinjection sites is, in the opinion of the investigator, unacceptably obscured due toa physical condition or permanent body art.

• History of organ transplant, including allogeneic stem cell transplantation.

• Receiving any other investigational agents within 4 weeks of beginning studytreatment.

• Uncontrolled intercurrent illness including, but not limited to, ongoing or activeinfection requiring systemic antibiotics or antifungal treatment, symptomaticcongestive heart failure, unstable angina pectoris, cardiac arrhythmia, orpsychiatric illness/social situations that would limit compliance with studyrequirements.

• Evidence of interstitial lung disease, history of interstitial lung disease, oractive, non-infectious pneumonitis.

• Presence of clinically significant increased intracranial pressure (e.g. impendingherniation) or hemorrhage, uncontrolled seizures, or requirement for immediatepalliative treatment.

• Pregnant and/or breastfeeding. Women of childbearing potential must have a negativepregnancy test within 7 days of first dose of vaccine.

• Has received a live vaccine within 28 days of the planned start of study drug.Participants may receive the COVID-19 vaccine as long as it is not a live vaccine.COVID-19 vaccination will be captured in the eCRF as a concomitant medication.Administration of study treatment may be delayed to ensure vaccination is completed.

• Active HBV or HCV infection that requires treatment. Hepatitis B virus DNA and HCVRNA must be undetectable upon testing. Participants who have cleared a prior HBVinfection (defined as HBsAg negative, hepatitis B surface antibody positive,hepatitis B core antibody positive) are eligible for the study.

• Note: For participants with cleared prior HBV infection, HBV prophylaxis shouldbe considered per the investigator's discretion. Monitor for HBV reactivationevery 3 cycles by performing HBV viral load and HBsAg serology test. Additionalviral serologic testing may be performed at the investigator's discretion.

• Note: Participants with no prior history of HBV infection who have beenvaccinated against HBV and who have a positive test result for antibody tohepatitis B surface antigen as the only evidence of prior exposure mayparticipate in the study.

• Note: Hepatitis C antibody-positive participants who received and completedtreatment for hepatitis C that was intended to eradicate the virus mayparticipate if HCV RNA levels are undetectable.