A Study of IMO-2125 in Combination With Ipilimumab Versus Ipilimumab Alone in Subjects With Anti-PD-1 Refractory Melanoma (ILLUMINATE-301)

A Phase 3 global, multi-center, open-label comparison of ipilimumab with and without
intratumoral IMO-2125 in subjects with advanced melanoma who had confirmed disease
progression while on nivolumab or pembrolizumab

Inclusion Criteria:

1. Subjects must be willing and able to sign the informed consent and comply with the
study protocol.

2. Subjects must be ≥18 years of age.

3. Subjects must have histologically confirmed metastatic melanoma with measurable (by
RECIST v1.1), stage III (lymph node or in transit lesions) or stage IVA, IVB, or IVC
disease that is accessible for injection.

4. Patients must have confirmed progression during or after treatment with either
nivolumab or pembrolizumab. Confirmed progression is defined as:

- Radiological progression (confirmed at least 4 weeks after the initial scan
showing PD); or

- (For progression based solely on worsening of non-target or new, non-measurable
disease) confirmation by an additional scan at least 4 weeks after the initial
scan unless it is accompanied by correlative symptoms.

In addition, all the following must hold:

1. No intervening anti-cancer therapy between the last course of nivolumab or
pembrolizumab and the first dose of study treatment is allowed except for local
measures (e.g., surgical excision or biopsy, focal radiation therapy).

2. The interval between last nivolumab or pembrolizumab and start of study treatment
should be at least 21 days with no residual anti-PD-1-related immune toxicities
in excess of Grade 1 severity.

3. If BRAF mutation status is unknown, before randomization the subject must have
BRAF testing performed using an approved assay method.

4. Patients with BRAF-positive tumor(s) are eligible for the study if they received
prior treatment with a BRAF inhibitor (alone of in combination with a MEK
inhibitor) or declined targeted therapy.

5. Patients must have Eastern Cooperative Oncology Group (ECOG) Performance Status ≤ 1.

6. Patients must meet the following laboratory criteria:

1. Absolute neutrophil count (ANC) ≥ 1.5 x 10^9/L (1500/mm3)

2. Platelet count ≥ 75 x 10^9/L (75,000/mm3)

3. Hemoglobin ≥ 8.0 g/dL (4.96 mmol/L)

4. Serum creatinine ≤ 1.5 x upper limit of normal (ULN) or calculated creatinine
clearance ≥ 60 mL/minute

5. Aspartate aminotransferase (AST) ≤ 2.5 x ULN; alanine aminotransferase (ALT) ≤
2.5 x ULN; AST/ALT < 5 x ULN if liver involvement

6. Serum bilirubin ≤ 1.5 x ULN, except in subjects with Gilbert's Syndrome who must
have a total bilirubin < 3 mg/dL

7. Women of childbearing potential (WOCBP) and men must agree to use effective
contraceptive methods from Screening throughout the study treatment period and until
at least 90 days after the last dose of either ipilimumab or IMO-2125, whichever is
later.

8. WOCBP must have a negative pregnancy test (serum or urine).

Exclusion Criteria:

1. Ocular melanoma.

2. Prior therapy with a toll-like receptor (TLR) agonist, excluding topical agents.

3. Prior ipilimumab treatment with the exception of adjuvant treatment completed ≥6
months prior to enrollment

4. Systemic treatment with interferon (IFN)-α within the previous 6 months.

5. Known hypersensitivity to any oligodeoxynucleotide.

6. Active autoimmune disease requiring disease-modifying therapy at the time of
Screening.

7. Subjects requiring systemic steroid therapy should be receiving ≤ 10 mg/day of
prednisone (or equivalent) for the 2 weeks preceding start of study.

8. Subjects with another primary malignancy that has not been in remission for at least 3
years, with the exception of non-melanoma skin cancer, curatively treated localized
prostate cancer with non-detectable prostate-specific antigen, cervical carcinoma in
situ on biopsy or a squamous intraepithelial lesion on Papanicolaou (Pap) smear, and
thyroid cancer (except anaplastic).

9. Active systemic infections requiring antibiotics

10. Active hepatitis A, B, or C infection.

11. Known diagnosis of human immunodeficiency virus (HIV) infection.

12. Women who are pregnant or breastfeeding.

13. Prior severe reaction to treatment with a human antibody that cannot be managed with
standard supportive measures.

14. Known central nervous system, meningeal, or epidural disease. However, subjects with
known brain metastases are allowed if the brain metastases are stable for ≥4 weeks
before the first dose of study treatment.

15. Impaired cardiac function or clinically significant cardiac disease.