DC Migration Study to Evaluate TReg Depletion In GBM Patients With and Without Varlilumab

Human cytomegalovirus (CMV) is a common endemic β-Herpesvirus, and over half of adults have
been infected with CMV. CMV does not usually cause significant clinical disease but can cause
health problems for people with weakened immune systems. Expression of proteins unique to
human CMV has been reported within a large proportion of malignant gliomas (MGs), including
detection of the human CMV immunodominant protein pp65-LAMP (pp65-lysosomal-associated
membrane protein). Human CMV antigens were not detected in surrounding normal brain samples.
The presence of highly-immunogenic human CMV antigens within MGs affords a unique opportunity
to target these tumors immunologically.

Dendritic cells (DCs) are antigen-presenting cells in the immune system. DCs are activated
then migrate to the lymph nodes to interact with T cells and B cells, which initiates the
adaptive immune response. This study generates autologous DCs from peripheral blood
leukocytes obtained from the subject during leukapheresis. RNA transfection is the method
used in this study for loading antigens onto DCs. DCs are pulsed with human CMV pp65-LAMP
mRNA.

The in vivo distribution of DCs will be evaluated in Vaccine #4 using 111Indium
(111In)-labeled pp65-LAMP mRNA loaded mature DCs. 111In-labeled DCs have been used
extensively for evaluation of adoptively transferred tumor infiltrating lymphocytes, natural
killer cells, granulocytes, dendritic cells, and whole blood leukocytes, for in vivo
localization studies in humans. Subjects will undergo SPECT/CT imaging immediately after
Vaccine #4 and then at 1 and 2 days after injection.

Tetanus-diphtheria (Td) toxoid is used for active immunization in children and adults against
infection with the bacteria Clostridium tetani and Corynebacterium diphtheria. It is thought
that Td toxoid induces an inflammatory milieu within the intradermal vaccine site, thereby
promoting the migration of injected tumor-specific DCs. Additionally, in the context of
vaccinating the host with tumor-derived peptides, conditioning the vaccine site with Td
toxoid has demonstrated enhanced immunogenicity with these peptides. Previous trials have
suggested that giving the Td prior to immunotherapy may help improve the effectiveness of the
DC vaccine by activating the immune response. This study will further examine whether Td
helps activate the immune response by comparing subjects who receive Td pre-conditioning to
subjects who receive autologous unpulsed DCs as pre-conditioning.

Varlilumab is a fully human monoclonal antibody (mAb) that targets CD27, a critical molecule
in the activation pathway of lymphocytes. Varlilumab is an agonist anti-CD27 mAb that has
been shown to activate human T cells in the context of T cell receptor stimulation. In
pre-clinical models, varlilumab has been shown to mediate anti-tumor effects and may be
particularly effective in combination with other immunotherapies. Anti-CD27 mAb has emerged
as a novel costimulatory immune modulator that depletes TRegs without impairing activated
effector T cells to improve antitumor immunity.

To examine the impact of Varlilumab on T cell responses to naïve antigen, pp65-loaded DC
Vaccine #1 will also include separate DCs loaded with the full mRNA of HIV Gag protein;
responses to HIV-Gag are uncommon and can serve as a naïve antigen in our HIV negative
patient population. It has been shown that removal of regulatory T cells (TRegs) can enhance
polyfunctional T-cell responses to HIV Gag. We hypothesize that TReg inhibition through
Varlilumab may increase polyfunctional immune responses to CMV.

Inclusion Criteria:

- Age ≥18 years of age.

- Glioblastoma with definitive resection prior to enrollment, with residual radiographic
contrast enhancing disease on the post-operative CT or MRI of <1 cm in maximal
diameter in any axial plane.

- Enough tumor tissue available for determination of MGMT gene promoter status.

- CMV Seropositive.

- KPS of ≥ 80%

- Hemoglobin ≥ 9.0 g/dl, ANC ≥ 1,500 cells/µl, platelets ≥ 100,000 cells/µl.

- Serum creatinine ≤ 1.5 mg/dl, serum SGOT and bilirubin ≤ 1.5 times upper limit of
normal.

- Signed informed consent approved by the Institutional Review Board.

- Female patients must not be pregnant or breast-feeding. Female patients of
childbearing potential (defined as < 2 years after last menstruation or not surgically
sterile) must use a highly effective contraceptive method (allowed methods of birth
control, [i.e. with a failure rate of < 1% per year] are implants, injectables,
combined oral contraceptives, intra-uterine device [IUD; only hormonal], sexual
abstinence or vasectomized partner) during the trial and for a period of > 6 months
following the last administration of trial drug(s). Female patients with an intact
uterus (unless amenorrhea for the last 24 months) must have a negative serum pregnancy
test within 48 hours prior to first study treatment.

- Fertile male patients must agree to use a highly effective contraceptive method
(allowed methods of birth control [i.e. with a failure rate of < 1% per year] include
a female partner using implants, injectables, combined oral contraceptives, IUDs [only
hormonal], sexual abstinence or prior vasectomy) during the trial and for a period of
> 6 months following the last administration of trial drugs.

Exclusion Criteria:

- Pregnant or breast-feeding.

- Women of childbearing potential and men who are sexually active and not willing/able
to use medically acceptable forms of contraception.

- Patients with known potentially anaphylactic allergic reactions to gadolinium-DTPA.

- Patients who cannot undergo MRI or SPECT due to obesity or to having certain metal in
their bodies (specifically pacemakers, infusion pumps, metal aneurysm clips, metal
prostheses, joints, rods, or plates).

- Patients with evidence of tumor in the brainstem, cerebellum, or spinal cord,
radiological evidence of multifocal disease, or leptomeningeal disease.

- Severe, active comorbidity, including any of the following:

- Unstable angina and/or congestive heart failure requiring hospitalization;

- Transmural myocardial infarction within the last 6 months;

- Acute bacterial or fungal infection requiring intravenous antibiotics at the time
of study initiation;

- Chronic obstructive pulmonary disease exacerbation or other respiratory illness
requiring hospitalization or precluding study therapy;

- Known hepatic insufficiency resulting in clinical jaundice and/or coagulation
defects;

- Known HIV and Hepatitis C positive status;

- Major medical illnesses or psychiatric impairments that, in the investigator's
opinion, will prevent administration or completion of protocol therapy;

- Active connective tissue disorders, such as lupus or scleroderma that, in the
opinion of the treating physician, may put the patient at high risk for radiation
toxicity.

- Co-medication that may interfere with study results; e.g. immuno-suppressive agents
other than corticosteroids.

- Prior, unrelated malignancy requiring current active treatment with the exception of
cervical carcinoma in situ and adequately treated basal cell or squamous cell
carcinoma of the skin. (Treatment with tamoxifen or aromatase inhibitors or other
hormonal therapy that may be indicated in prevention of prior cancer disease
recurrence, are not considered current active treatment.)

- Patients are not permitted to have had any other conventional therapeutic intervention
other than steroids prior to enrollment outside of standard of care chemotherapy and
radiation therapy. Patients who receive previous inguinal lymph node dissection,
radiosurgery, brachytherapy, or radiolabeled monoclonal antibodies will be excluded.

- Current, recent (within 4 weeks of the administration of this study agent), or planned
participation in an experimental drug study.

- Known history of autoimmune disease (with the exceptions of medically-controlled
hypothyroidism and Type I Diabetes Mellitus).