A Study of DSP-7888 Dosing Emulsion in Combination With Immune Checkpoint Inhibitors in Adult Subjects With Advanced Solid Tumors

Inclusion Criteria

Subjects must fulfil all of the following requirements:

1. A histologically or cytologically confirmed cancer that is metastatic and is approved
to be treated with Nivolumab or Atezolizumab with the following origins: melanoma,
NSCLC, HNSCC, RCC, and urothelial cancer, as well as the following:

1. Subjects must not be considered eligible for a potentially curative resection.

2. Subjects who are eligible for PD-1/PD-L1 therapy or who have exhausted all
standard therapies for their disease except for immunotherapy.

either c) or d)

3. Subjects progressed on their prior treatment before initiating treatment on
current study.

Or

4. Subjects, who are currently being treated with PD-1 or PD-L1 inhibitors Nivolumab
or Atezolizumab and have achieved at least stable disease (SD), and who, in the
judgment of their treating physicians, could benefit from the addition of
DSP-7888 vaccine to improve or maintain their response.

In expansion part only: All subjects who are candidates for immunotherapy including
PD-1/PD-L1 inhibitors are eligible to enroll in the study. Subjects must have at least
1 target lesion based on RECIST criteria and other supporting disease specific
evaluation criteria.

2. Subjects must be positive for at least 1 of the following human leukocyte antigens
(HLA):

1. HLA-A*02:01

2. HLA-A*02:06

3. HLA-A*24:02

3. ≥ 18 years of age.

4. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

5. Either archival tumor tissue must be available or subject must consent to undergo a
tumor biopsy before administration of first dose.

6. Females of childbearing potential must have a negative serum pregnancy test.

7. Male or female subjects of child-producing potential must agree to use contraception
or use prevention of pregnancy measures (true abstinence) during the study and for 150
days after the last dose.

8. Total bilirubin of ≤ 2.0 mg/dL (≤ 3.0 mg/dL for subjects with known Gilbert's
syndrome)

9. Aspartate aminotransferase (AST) ≤ 3.0 × the upper limit of normal (ULN) or < 5 × ULN
if considered to be due to liver metastases.

10. Alanine transaminase (ALT) ≤ 3.0 × the upper limit of normal (ULN) or < 5 × ULN if
considered to be due to liver metastases.

11. Glomerular Filtration Rate > 40 mL/min.

12. Multigated acquisition (MUGA) scan or echocardiogram with left ventricular ejection
fraction (LVEF) > 40%.

13. Life expectancy ≥ 3 months.

14. Subjects must be willing to provide a personally signed and dated informed consent
document.

Exclusion Criteria

Subjects with any of the following will be excluded from the study:

1. Anticancer chemotherapy (including molecular targeted drugs), immunotherapy, or
investigational agents within 7 days of the first dose of DSP-7888; radiotherapy
within 4 weeks of the first dose of DSP-7888. Subjects may begin DSP-7888 on a date
determined by the Investigator and medical monitor for the Sponsor provided that all
treatment related adverse events (AEs) have resolved or have been deemed irreversible.
This exclusion is not applied to subjects who meet the inclusion criterion 1d.

2. In expansion part only: Subjects progressed on their prior checkpoint inhibitors
(PD-1/PD-L1) treatment before initiating treatment on current study.

3. Major surgery within 4 weeks prior to study treatment.

4. Subject has received a live vaccine within 30 days prior to the first dose.

5. Any known, untreated brain metastases. Subjects with treated brain metastases must be
clinically stable for 4 weeks after completion of treatment for brain metastases and
have radiographic image documentation of stability. Subjects must have no clinical
symptoms from brain metastases and not have required systemic corticosteroids > 10
mg/day prednisone or equivalent for at least 2 weeks prior to the first dose of study
drug.

6. Subject has multifocal glioblastoma.

7. Pregnant or breastfeeding.

8. Subject has an active autoimmune disease requiring immunosuppression with the
exception of subjects with isolated vitiligo, resolved childhood asthma or atopic
dermatitis, controlled hypoadrenalism or hypopituitarism, and euthyroid subjects with
a history of Grave's disease.

a. Subjects with controlled hyperthyroidism must be negative for thyroglobulin and
thyroid peroxidase antibodies and thyroid stimulating immunoglobulin prior to study
drug administration.

9. Subject has interstitial lung disease or active, non-infectious pneumonitis.

10. Known hypersensitivity to a component of protocol therapy.

1. Subjects with known hypersensitivity to any of the components of DSP-7888 Dosing
Emulsion.

2. Subjects with known hypersensitivity to Nivolumab or Atezolizumab are excluded
from receiving combination therapy that includes the agent to which they are
hypersensitive.

11. Uncontrolled concurrent illness including, but not limited to, ongoing or active
infection, clinically significant non-healing or healing wounds, symptomatic
congestive heart failure, unstable angina pectoris, severe and/or uncontrolled cardiac
arrhythmia, significant pulmonary disease, uncontrolled infection or psychiatric
illness/social situations that would limit compliance with study requirements.

12. Subjects with a history of another primary cancer with the exception of: a) curatively
resected non-melanoma skin cancer; b) curatively treated cervical carcinoma in situ;
c) localized prostate cancer not requiring systemic therapy; and d) any another cancer
from which the subject has been disease free for ≥ 2 years that, in the opinion of the
Investigator and medical monitor for the Sponsor, will not affect subject outcome in
the setting of the current diagnosis.

13. Patient has a QTcF (QT corrected based on Fridericia's equation) interval > 480 msec
(CTCAE = Grade 2) or other factors that increase the risk of QT prolongation or
arrhythmic events (e.g., heart failure, hypokalemia, family history of long QT
interval syndrome) at screening. (Patients with bundle branch block and a prolonged
QTc interval should be reviewed by the Medical Monitor for potential inclusion.)

14. Subject has a medical history of frequent or sustained ventricular ectopy.

15. Subject has, in the opinion of the treating Investigator, any concurrent conditions
that could pose an undue medical hazard or interfere with the interpretation of the
study results.

16. Known history of human immunodeficiency virus (HIV) infection, active hepatitis B, or
untreated hepatitis C; patients who have completed a course of anti-viral treatment
for hepatitis C are eligible.

17. Subject has baseline signs and symptoms consistent with clinically significant,
decreased pulmonary function: (1) blood saturation oxygen level (SpO2) < 90% at rest
on room air; (2) dyspnea at rest or required supplemental oxygen within 2 weeks of
study enrollment.