Neuro-Oncology Branch National Cancer Institute National Institutes of Health Bloch Bldg. 82, Rm. 217 9030 Old Georgetown Road Bethesda, MD 20892 Email: byram.ozer@nih.gov BTTC COORDINATING CENTER National Cancer Institute National Institutes of Health 9030 Old Georgetown Road Bloch Bldg. 82, Room 229 Bethesda, MD 20892 Phone: 240-760-6060 Email: nci_bttc@mail.nih.gov BTTC PARTICIPATING INVESTIGATORS/SITES (ENROLLING): The BTTC Participating Investigators/Sites listed in the NIH IRB system will enroll study subjects as described in the protocol. Each site will obtain IRB Approval at their site. A DISCLAIMER STATEMENT FOR BTTC PROTOCOLS This is a research protocol of the Brain Tumor Trials Collaborative describing an experimental treatment procedure. It is a privileged document and is not intended to be circulated or used for other purposes. The Brain Tumor Trials Collaborative assumes no responsibility for its use outside of the constraints of this research protocol or by investigators other than those approved by the Consortium. 3 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 PRÉCIS Background: Malignant gliomas are unfortunately, in most cases, a uniformly fatal tumor. Despite aggressive surgery, radiation treatment (RT) and chemotherapy at initial diagnosis these tumors almost always recur. Many clinical trials in glioblastoma (GBM) have evaluated the addition of agent(s) to standard therapy which consists of concurrent radiation with temozolomide chemotherapy after maximal surgical resection in patients with newly diagnosed disease and salvage chemotherapy with either rechallenge with temozolomide or an alternative alkylating agent such as CCNU or cisplatin. To date, none of the combination strategies have demonstrated clinical benefit. Furthermore, in subjects with an unmethylated MGMT (O6-methylguanine-DNA methyltransferase) promoter temozolomide has only modest benefit and salvage therapies have not demonstrated a significant impact in this subject group underscoring the need for more research. Immunotherapy offers the promise of improving outcomes for patients with GBM by evoking specific immune responses that may produce a more sustained and less toxic effect than conventional therapy. Heat-shock proteins (HSPs), which function as intracellular chaperones, can be used to deliver a variety of tumor antigens to antigen presenting cells for immune stimulation. Heat Shock Protein-Peptide Complex-96 (HSPPC-96) consists of the heat shock protein glycoprotein-96 (HSP gp-96) and a wide array of chaperoned proteins, including autologous antigenic peptides (aka “vaccine”). Heat shock proteins (HSP) are molecules that respond to cellular stress and counteract abnormal protein folding. They are known to modulate immune responses, especially the HSP gp-96. In a stressful environment, such as a tumor, HSPs are upregulated and highly expressed on tumor cells. This protects the tumor and leads to resistance to therapy. HSP expression is associated with cellular proliferation, apoptosis evasion, tissue invasion, metastasis, and angiogenesis. Pembrolizumab is a potent and highly selective humanized monoclonal antibody (mAb) of the IgG4/kappa isotype designed to directly block the interaction between PD-1 and its ligands, PD-L1 and PD-L2. Additionally, pembrolizumab is thought to also have activity in the peripherally circulating T-effector cells by reversing lymphocyte exhaustion. It is currently FDA approved for use in patients with unresectable or metastatic melanoma and disease progression following ipilimumab and, if BRAF V600 mutation positive, a BRAF inhibitor and NSCLC with elevated PD- L1 in the tumor. recurrent or metastatic HNSCC with disease progression on or after platinum-containing chemotherapy. It is also FDA approved for use with advanced (metastatic) non-small cell lung cancer (NSCLC) whose disease has progressed after other treatments and with tumors that express a protein called PD-L1 and for the treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) with disease progression on or after platinum-containing chemotherapy This study will be the first to evaluate this combination of vaccine (HSPPC-96) and PD- 1 inhibition (pembrolizumab) in newly diagnosed GBM patients whose tumors are MGMT promoter unmethylated and are isocytrate dehydrogenase (IDH) wildtype; and 4 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 will provide important data on immune-modulatory effect of this combination. This may be of particular value in patients with high peripheral PD-L1 expression, but also the value of PD-1 added to standard GBM therapy. As vaccine needs to be generated from the patient’s tumor, patients will need to be identified prior to surgery. Eligibility: MRI findings consistent with a suspected GBM or histologically confirmed newly diagnosed GBM that has not been treated and would benefit from further surgical resection. Tumor must be supratentorial. GBM diagnosis must be made by surgical excision (stereotactic biopsy will not be allowed unless there is plan for second surgery to remove ≥ 80 % of the tumor) and patients tumors must not have MGMT promoter methylation and must be IDH wildtype. No prior treatment with radiation or chemotherapy for their GBM. Age ≥ 18 years on day of signing informed consent Objective: The primary endpoint is to determine whether the one-year overall survival (OS) rate is improved in newly diagnosed GBM patients whose tumors have an unmethylated MGMT promoter and are IDH wildtype treated with RT + TMZ + Pembrolizumab followed by TMZ + Pembrolizumab + HSPPC-96 vaccine or Placebo vaccine x 6 cycles (1 cycle is 9 weeks). Design: This will be a randomized, double blind phase II trial of surgery, RT + TMZ + Pembrolizumab followed by TMZ + Pembrolizumab +/- HSPPC-96 in newly diagnosed GBM patients whose tumors have an unmethylated MGMT promoter and are IDH wildtype. Subjects will be assigned to intervention based on ability to generate vaccine as follows: oIf ≥ 80 % of tumor removed and ≥7 g of tumor is resected but HSPPC-96 cannot be generated, subjects will be treated on the ancillary arm of RT+TMZ +Pembrolizumab followed by TMZ+ Pembrolizumab. oIf ≥ 80% of contrasting enhanced tumor removed (based on T1 Post contrast MRI using cross sectional measurement), ≥7 g of tumor is resected and sufficient HSPPC-96 is generated, subjects will be included in the main cohort and will be randomized on a 1:1 basis to receive: RT+TMZ +Pembrolizumab followed by TMZ+Pembrolizumab + Placebo OR RT+TMZ +Pembrolizumab followed by TMZ+Pembrolizumab+HSPPC- 96 Subjects whose tumor does not meet the criteria (unmethylated MGMT promoter and IDH wildtype by pathology) and for whom < 80 % of tumor is removed or < 7g of tumor is resected are not eligible for further intervention. Approximately 8 potentially eligible 5 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 patients are screened per month, and it is anticipated that at least 1-2 per month will be accrued per site. 6 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 TABLE OF CONTENTS PRÉCIS ...........................................................................................................................................3 TABLE OF CONTENTS ................................................................................................................6 SCHEMA.......................................................................................................................................14 STATEMENT OF COMPLIANCE ..............................................................................................16 1. INTRODUCTION..................................................................................................................17 1.1 Study Objectives..........................................................................................................17 1.1.1 Primary Objective: ..................................................................................................17 1.1.2 Secondary Objectives:.............................................................................................17 1.1.3 Exploratory Objectives:...........................................................................................17 1.2 Background and Rationale...........................................................................................18 1.2.1 Disease Background................................................................................................18 1.2.2 Intervention Background & Overview....................................................................19 1.2.3 Rationale for the Pembrolizumab dose ...................................................................20 1.2.4 Heat Shock Protein-Peptide Complex-96 (HSPPC-96) ..........................................21 1.2.5 Rationale for the Current Study ..............................................................................23 1.2.6 Rationale for the patient-reported outcomes:..........................................................24 2 ELIGIBILITY ASSESSMENT AND ENROLLMENT........................................................25 2.1 Eligibility Criteria........................................................................................................25 2.1.1 Inclusion Criteria.....................................................................................................25 2.1.2 Exclusion Criteria....................................................................................................27 2.1.3 Recruitment Strategies ............................................................................................30 2.2 Screening Evaluation ...................................................................................................30 2.2.1 Screening activities performed prior to obtaining informed consent......................30 2.2.2 Screening activities performed after a consent for screening has been signed .......30 2.3 Participant Registration and Status Update Procedures...............................................31 2.3.1 Informed Consent/Authorization.............................................................................31 2.3.2 Registration at the NCI............................................................................................31 2.3.3 Registration at Participating BTTC Sites................................................................31 2.3.4 Initiation of Therapy (Radiation Therapy, Temozolomide and Pembrolizumab)...32 2.3.5 Registration Step 3: Randomization for NCI ..........................................................32 2.3.6 Registration Step 3: Randomization for Participating Sites....................................33 7 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 2.3.7 Study Status Updates for Participating Sites...........................................................33 2.3.8 Screen Failures ........................................................................................................33 2.4 Treatment Assignment and Randomization /Stratification Procedures.......................33 3 STUDY IMPLEMENTATION..............................................................................................35 3.1 Early Termmination.....................................................................................................35 3.2 Study Design................................................................................................................35 3.2.1 Blinding...................................................................................................................36 3.3 Surgery & Tissue Collection for Vaccine Administration ..........................................37 3.3.1 Surgery ....................................................................................................................37 3.3.2 Tissue Collection for Vaccine Production at NCI...................................................37 3.3.3 Tissue Collection for Vaccine Production at Participating BTTC Sites .................38 3.4 Radiation Therapy (RT)...............................................................................................38 3.5 Drug Administration....................................................................................................38 3.5.1 (RT+TMZ+Pembro)................................................................................................38 3.5.2 HSPPC-96 Vaccine or Placebo ...............................................................................38 3.6 Post RT Treatment Regimen .......................................................................................39 3.6.1 For patients not randomized (ancillary arm 2)........................................................39 3.6.2 For patients randomized to vaccine or placebo.......................................................39 3.7 Baseline Assessments (Post-Surgery And Pre-Treatment RT+TMZ+Pembro) ..........40 3.8 Assessments While On Trial During And Post RT .....................................................40 3.8.1 Questionnaires.........................................................................................................41 3.9 Telehealth/Remote Visits.............................................................................................42 3.10 Dose Modifications......................................................................................................43 3.10.1 Pembrolizumab Dose Modifications.......................................................................43 3.10.2 Guidelines for Drug-Related Adverse Events due to Pembrolizumab....................50 3.10.3 Pembrolizumab Supportive Care ............................................................................50 3.10.4 Temozolomide Dose Modifications........................................................................52 3.10.5 HSPPC-96/Placebo Dose Modifications.................................................................53 3.10.6 Vaccine Injection Site Reactions.............................................................................53 3.11 Study Calendar.............................................................................................................54 3.12 Surgical Guidelines......................................................................................................57 3.13 Cost and Compensation ...............................................................................................57 8 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 3.13.1 Costs........................................................................................................................57 3.13.2 Compensation..........................................................................................................57 3.13.3 Reimbursement........................................................................................................57 3.14 Criteria for Removal from Protocol Therapy and Off Study Criteria .........................57 3.14.1 Criteria for Removal from Protocol Therapy..........................................................57 3.14.2 Off Study Criteria....................................................................................................58 3.14.3 Lost to Follow-up....................................................................................................58 4 CONCOMITANT MEDICATIONS/VACCINATIONS (ALLOWED & PROHIBITED) ..58 4.1 Acceptable Concomitant Medications.........................................................................59 4.2 Prohibited Concomitant Medications ..........................................................................59 4.3 Diet/Activity/Other Considerations .............................................................................60 4.3.1 Diet..........................................................................................................................60 4.3.2 Contraception ..........................................................................................................60 5 BIOSPECIMEN COLLECTION ...........................................................................................61 5.1 Correlative Studies for Research/Pharmacokinetic Studies ........................................61 5.1.1 Collection of correlative blood time points:............................................................62 5.1.2 PD-L1 expression on tumor cells............................................................................62 5.1.3 Tissue will be interrogated by Next Generation Sequencing for tumor antigens ...62 5.1.4 Tissue Collection at NCI.........................................................................................63 5.1.5 Sample Storage, Tracking and Disposition.............................................................63 5.2 Samples for Genetic/Genomic Analysis......................................................................63 5.2.1 Scope of the analysis...............................................................................................63 5.2.2 Certificate of Confidentiality ..................................................................................64 5.2.3 Incidental Findings..................................................................................................64 6 DATA COLLECTION AND EVALUATION......................................................................64 6.1 Data Collection ............................................................................................................64 6.1.1 Exceptions to Data Collection.................................................................................65 6.1.2 Source Documentation Timeframes........................................................................65 6.1.3 Database Entry Timeframes....................................................................................66 6.1.4 Confidentiality.........................................................................................................67 6.1.5 Safety Data ..............................................................................................................67 6.1.6 Data Monitoring ......................................................................................................68 9 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 6.2 Data Sharing Plans.......................................................................................................68 6.2.1 Human Data Sharing Plan.......................................................................................68 6.2.2 Genomic Data Sharing Plan ....................................................................................68 6.3 Response Criteria.........................................................................................................69 6.3.1 Definitions...............................................................................................................69 6.3.2 Disease Parameters..................................................................................................69 6.3.3 RANO Criteria for Response ..................................................................................69 6.3.4 iRANO (Exploratory)[45].......................................................................................70 6.3.5 Evaluation of Best Overall Response......................................................................71 6.3.6 Dose Limiting Toxicity ...........................................................................................71 6.3.7 Progression-Free Survival.......................................................................................71 6.3.8 Overall survival.......................................................................................................71 6.3.9 Response Review ....................................................................................................71 6.4 Toxicity Criteria...........................................................................................................72 7 NIH REPORTING REQUIREMENTS/DATA AND SAFETY MONITORING PLAN .....72 7.1 Definitions ...................................................................................................................72 7.2 OHSRP Office of Compliance and Training / IRB Reporting ....................................72 7.2.1 Expedited Reporting................................................................................................72 7.2.2 IRB Requirements for NCI PI Reporting at Continuing Review............................72 7.3 NCI Clinical Director Reporting .................................................................................72 7.4 NCI Guidance For Reporting Expedited Adverse Events For Multi-Center Trials ....73 7.4.1 Reporting Deviations and Unanticipated Problems for Multi-Center Trials ..........74 7.5 NIH Required Data and Safety Monitoring Plan.........................................................74 7.5.1 Data Safety Monitoring Board (DSMB) .................................................................75 7.5.2 Patient-Reported Outcomes.....................................................................................75 7.6 Exploratory Objectives & Endpoints...........................................................................76 8 SPONSOR PROTOCOL/SAFETY REPORTING ................................................................76 8.1 Definitions ...................................................................................................................76 8.1.1 Adverse Event .........................................................................................................76 8.1.2 Serious Adverse Event (SAE).................................................................................76 8.1.3 Life-threatening.......................................................................................................77 8.1.4 Severity....................................................................................................................77 10 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 8.1.6 Events Of Clinical Interest (ECI) For This Trial Include: ......................................78 8.1.7 Definition of an Overdose for This Protocol and Reporting of Overdose to the Sponsor....................................................................................................................78 8.2 Assessment of Safety Events .......................................................................................79 8.3 Reporting of Serious Adverse Events..........................................................................79 8.4 Safety Reporting Criteria to The Pharmaceutical Collaborators .................................79 8.4.1 To be Sent by OSROSafety.....................................................................................79 8.4.2 To be Sent by BTTC study team.............................................................................80 8.4.3 Events of Clinical Interest.......................................................................................81 8.4.4 Reporting Serious Adverse Events to Merck and Agenus ......................................82 8.5 Reporting Pregnancy ...................................................................................................82 8.5.1 Maternal exposure ..................................................................................................82 8.5.2 Paternal exposure ....................................................................................................83 8.6 Regulatory Reporting for Studies Conducted Under CCR Sponsored IND................83 9 CLINICAL MONITORING ..................................................................................................83 10 STATISTICAL CONSIDERATIONS...................................................................................84 10.1 Sample Size and Accrual .............................................................................................85 10.2 Data Analyses Plans.....................................................................................................86 10.3 Secondary Objectives & Endpoints .............................................................................86 11 COLLABORATIVE AGREEMENTS ..................................................................................86 11.1 Agreement Type ..........................................................................................................86 11.2 Multi-Institutional Guidelines .....................................................................................86 11.2.1 Participating Institution Site Initiation ....................................................................86 11.2.2 IRB Approvals.........................................................................................................87 12 HUMAN SUBJECTS PROTECTIONS ................................................................................87 12.1 Rationale For Subject Selection...................................................................................87 12.2 Participation of Children..............................................................................................87 12.3 Participation of Subjects Unable to Give Consent (NCI)............................................87 12.4 Participation of Adults Unable to Give Consent (BTTC) ...........................................88 12.5 Evaluation of Benefits and Risks/Discomforts............................................................88 12.5.1 Risks........................................................................................................................88 12.5.2 Benefits....................................................................................................................89 11 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 12.6 Consent Process and Documentation...........................................................................89 12.6.1 Consent Process for Adults Who Lack Capacity to Consent to Research Participation ............................................................................................................90 12.6.2 Request for Waiver of Consent for Screening Activities........................................90 12.6.3 Reconsent via phone at BTTC Sites (outside of NCI) ............................................90 13 REGULATORY AND OPERATIONAL CONSIDERATIONS ..........................................91 13.1 Study Discontinuation and Closure .............................................................................91 13.2 Quality Assurance and Quality Control.......................................................................91 13.3 Conflict of Interest Policy............................................................................................91 13.4 Confidentiality and Privacy .........................................................................................92 14 PHARMACEUTICAL INFORMATION..............................................................................93 14.1 Pembrolizumab/Keytruda ®........................................................................................93 14.1.1 Chemical Name.......................................................................................................93 14.1.2 CAS Name and Number..........................................................................................93 14.1.3 Molecular Formula: C 6534H10004N1716O2036S46 (peptide) .........................................93 14.1.4 Molecular Weight: 149 kDa....................................................................................93 14.1.5 Appearance..............................................................................................................93 14.1.6 Storage and Stability ...............................................................................................93 14.1.7 Supplier ...................................................................................................................93 14.1.8 Mechanism of Action..............................................................................................93 14.1.9 Administration for this study...................................................................................93 14.1.10 Preparation ..............................................................................................................94 14.1.11 Preparation for Intravenous Infusion.......................................................................94 14.1.12 Incompatibilities......................................................................................................94 14.1.13 Side Effects .............................................................................................................95 14.2 Temozolomide .............................................................................................................97 14.2.1 Chemical Name.......................................................................................................97 14.2.2 Molecular Formula: C 6H6N6O2...............................................................................97 14.2.3 Molecular Weight: 194.15.......................................................................................97 14.2.4 Appearance..............................................................................................................97 14.2.5 Supply: Commercially Available............................................................................97 14.2.6 Pill Diary .................................................................................................................97 12 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 14.2.7 Storage and Stability ...............................................................................................98 14.2.8 Metabolism and Elimination ...................................................................................98 14.2.9 Mechanism of Action..............................................................................................98 14.2.10 Special Populations .................................................................................................98 14.2.11 Drug-Drug Interactions ...........................................................................................99 14.2.12 Adverse Events:.......................................................................................................99 14.2.13 Special Handling and Precautions...........................................................................99 14.2.14 Contraindications ....................................................................................................99 14.2.15 Pregnancy Category D ............................................................................................99 14.2.16 Fertility..................................................................................................................100 14.3 Heat Shock Protein-Peptide Complex-96 Vaccine (HSPPC-96)...............................100 14.3.1 Molecular Formula................................................................................................100 14.3.2 Peptide Component ...............................................................................................100 14.3.3 Appearance............................................................................................................101 14.3.4 Availability............................................................................................................101 14.3.5 HSPPC-96 Vaccine Label .....................................................................................101 14.3.6 Storage and Stability .............................................................................................101 14.3.7 Preparation ............................................................................................................101 14.3.8 Administration.......................................................................................................101 14.3.9 Toxicities...............................................................................................................102 14.4 Placebo.......................................................................................................................102 14.4.1 Supply ...................................................................................................................102 14.4.2 Product Description...............................................................................................102 14.4.3 Placebo Label ........................................................................................................102 14.4.4 Storage...................................................................................................................102 14.4.5 Administration.......................................................................................................102 14.4.6 Dose.......................................................................................................................102 14.5 Ordering Study Agent................................................................................................103 14.5.1 Heat Shock Protein-Peptide Complex-96 .............................................................103 14.5.2 Pembrolizumab......................................................................................................103 14.5.3 Temozolomide.......................................................................................................103 14.5.4 Agent Storage and Accountability: .......................................................................103 13 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 14.5.5 BTTC Procedures for Agent Accountability and Storage.....................................104 14.5.6 Verification of Compliance...................................................................................105 14.6 Returning or destroying unused and/or defective agent: ...........................................105 14.6.1 Pembrolizumab Return Procedure ........................................................................105 14.6.2 HSPPC-96 or Placebo Return Procedure ..............................................................105 15 REFERENCES.....................................................................................................................106 16 APPENDICES......................................................................................................................109 16.1 Performance Status Criteria.......................................................................................109 16.2 Tumor Tissue Submission for Vaccine Manufacture ................................................110 16.3 Vaccine Tissue Procurement And Shipping Instructions ..........................................111 16.4 Tumor Procurement Form .........................................................................................116 16.5 LabConnect Manual for Whole Blood PBMC Processing and Shipping..................117 16.6 HSPPC-96 Vaccine or Placebo Return Instructions..................................................118 16.7 HSPPC-96 Intradermal Injection Instructions ...........................................................119 16.8 Infusion Reaction Treatment Guidelines ...................................................................122 16.9 MD Anderson Symptom Inventory (MDASI-BT) ....................................................124 16.10 CCR Reportable Event Form (REF)..........................................................................125 16.11 Unblinding Request Memo........................................................................................128 16.12 Unblinding Notification Memo .................................................................................130 16.13 Study Phases and Correlative Blood Draws ..............................................................131 16.14 Pill Diary....................................................................................................................132 16.15 Investigator Agreement .............................................................................................134 14 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 SCHEMA Patient comes off study if tumor type and both resection criteria not met MRI findings consistent with a suspected GBM or a histologically confirmed newly diagnosed GBM that has not been treated and would benefit from further surgical resection CR: complete response; DP: disease progression; GBM: glioblastoma multiforme; PR: partial response; RT: radiation therapy; SD: stable disease; TMZ: temozolomide.Arm 2: TMZ+ Pembrolizumab up to 6 cycles Surgery -tissue for vaccine production and neo- epitope monitoring RT + TMZ + Pembrolizumab Arm 4: TMZ + Pembrolizumab + placebo for a minimum of 6 cycles (or until number of cycles matches vaccine doses made)Randomization Once off treatment, continue follow-up every 8-16 weeks. CR: complete response; DP: disease progression; GBM: glioblastoma multiforme; PR: partial response; RT: radiation therapy; SD: stable disease; TMZ: temozolomide.After 6 cycles post-RT, subjects may continue on Pembrolizumab + vaccine or placebo (until depletion of vaccine or placebo). Subjects maybe continue on Pembrolizumab for up to 12 months if benefiting from treatment.After 6 cycles post-RT, subjects may continue on Pembrolizumab for another 12 months if benefiting from treatment.Arm 1: unmethylated MGMT promoter and IDH wildtype by pathology ≥ 80 % contrast enhanced tumor resected and ≥7 grams of tissue collected Arm 3: TMZ + Pembrolizumab + HSPPC-96 for a minimum of 6 cycles (or until vaccine depletion for HSPPC-96). Sufficient vaccine made (minimum of four) NO YES 15 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 CR: complete response; PD: Progressive Disease; GBM: glioblastoma multiforme; PR: partial response; RT: radiation therapy; SD: stable disease; TMZ: temozolomide.CR/PR/SD: continue treatment until PD or 2 years. 16 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 STATEMENT OF COMPLIANCE The trial will be carried out in accordance with International Council for Harmonisation Good Clinical Practice (ICH GCP) and the following: United States (US) Code of Federal Regulations (CFR) applicable to clinical studies (45 CFR Part 46, 21 CFR Part 50, 21 CFR Part 56, 21 CFR Part 312, and/or 21 CFR Part 812) National Institutes of Health (NIH)-funded investigators and clinical trial site staff who are responsible for the conduct, management, or oversight of NIH-funded clinical trials have completed Human Subjects Protection and ICH GCP Training. The protocol, informed consent form(s), recruitment materials, and all participant materials will be submitted to the Institutional Review Board (IRB) for review and approval. Approval of both the protocol and the consent form must be obtained before any participant is enrolled. Any amendment to the protocol will require review and approval by the IRB before the changes are implemented to the study. In addition, all changes to the consent form will be IRB-approved; an IRB determination will be made regarding whether a new consent needs to be obtained from participants who provided consent, using a previously approved consent form. 17 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 1. INTRODUCTION 1.1 STUDY O BJECTIVES 1.1.1 Primary Objective: oTo determine whether the one-year overall survival rate (OS) is improved in newly diagnosed GBM patients whose tumors have an unmethylated MGMT promoter and are IDH wildtype treated with RT + Temozolomide (TMZ) + Pembrolizumab followed by Pembrolizumab + TMZ and either HSPPC-96 x 6 cycles (1 cycle is 9 weeks) or placebo vaccine. Nota Bene : Those patients whose tumor does not meet the criteria (unmethylated MGMT promoter and IDH wildtype by pathology) and with < 80% of contrast enhanced tumor removed or < 7g of tumor resected are ineligible. 1.1.2 Secondary Objectives: oTo determine the following oProgression Free Survival-6 (PFS-6) (percentage of patients alive and progression- free at 6 months post registration). oOverall Survival (OS). oOverall Survival ( OS) OS-6 and 24 (percentage of patients alive at 6 and 24 months respectively). oResponse will be determined by Table 2 below using RANO as main criteria. If a lesion is 25% larger but there remains a question as to disease progression or pseudoprogression due to treatment, the patient can remain on treatment until this can be defined, if true progression occurred earlier, the earlier date will be used. oSafety of Pembrolizumab +/- HSPPC-96 in GBM. oTo evaluate the occurrence of symptoms and correlate to disease progression and tolerance to treatment using the MD Anderson Symptom Inventory-Brain Tumor Module (MDASI-BT). This will include: To longitudinally evaluate patient reported outcome measures using self-reported symptom severity and interference with daily activities using the MDASI-BT questionnaire. To measure symptom burden over the course of therapy to evaluate differences between patients individual symptom severity, overall mean symptom severity, and difference in scores on the interference items between responders and non- responders. To describe the variability of symptom severity longitudinally over the treatment course and follow-up period. 1.1.3 Exploratory Objectives: oTo determine if there is a correlation with clinical outcome of PDL1 expression and T- Cell infiltrate in pathology from first, and if applicable, second surgical specimens with outcome. 18 Abbreviated Title: GBM Pembro HSPPC Version Date: 03/26/2024 oTo assess tumor tissue for neo-antigens. oTo collect peripheral monocytes for PD-L1 levels to confirm that low level expression leads to better outcome and if higher levels that are treated with Pembrolizumab might improve outcome. oAssess changes in peripheral T-Cell activation and tryptophan metabolites.