A Study to Evaluate the Safety and Effectiveness of ILIxadencel Administered Into Tumors in Combination With Checkpoint Inhibitor (CPI) in Patients With ADvanced Cancer

Despite improvements achieved with the use of CPIs, 50-80% of cancer patients do not respond
to this therapy. There is growing evidence that combining CPIs with other forms of
immunotherapy has the potential to improve the desired effects of both CPIs and
immunotherapies. This study looks at the safety and effectiveness of the immunotherapy
ilixadencel when used in combination with a CPI. A Dose-escalation Committee (DEC) will
monitor the study for any significant safety issues during Phase 1b.

Inclusion Criteria:

- Must provide written informed consent.

- Must have histologically confirmed and specific (Human Papilloma Virus) HPV-positive
or HPV-negative squamous cell carcinoma of the head and neck (SCCHN), non-small-cell
lung cancer (NSCLC) or gastric or gastroesophageal junction (GEJ) adenocarcinoma.
Tumor histology and most recent pathology report must be in subject's medical record.
Tumor samples and/or biopsies will not be collected as part of this study.

- Eligible for pembrolizumab treatment per country-specific label and per physician's
decision.

- ECOG 0 or 1.

- Adequate organ function.

- Women of childbearing potential must follow contraceptive requirements; must have a
negative pregnancy blood test at screening, and a negative blood or urine pregnancy
test within 24 hours before each dose of ilixadencel; and must not be breastfeeding.

- Male subjects must agree to use condoms from screening until 90 days after the last
dose of ilixadencel, or must have a female partner using a highly effective method of
contraception as described above.

Exclusion Criteria:

- Prior history of invasive malignancy, unless complete remission has been achieved for
at least 3 years and no additional therapy is required except for hormonal therapy or
bisphosphonates.

- Active or previously untreated brain and/or leptomeningeal metastasis.

- Active autoimmune disease, pneumonitis or interstitial lung disease.

- Certain heart conditions including, but not limited to: Congestive heart failure;
uncontrolled hypertension; unstable angina pectoris; pericarditis; myocarditis;
mycardial infarction 6 months prior to study.

- Systemic immunosuppression except for replacement therapy.

- Life expectancy of less than 3 months.

- Any prior treatment with ilixadencel or prior treatment with anticancer agents (except
pembrolizumab or other CPI for subjects in Phase 1b) within 4 weeks of starting study
medication.

- Major surgery or significant traumatic injury within 4 weeks before study start.

- Known infection with human immunodeficiency virus (HIV).

- Active tuberculosis; active infection with hepatitis B virus or hepatitis C virus;
active infection requiring anti-infective therapy.

Other protocol-defined inclusion/exclusion criteria could apply.