APX005M in Combination With Systemic Pembrolizumab in Patients With Metastatic Melanoma

Study Groups:

If you are found to be eligible to take part in this study, you will be assigned to a study
group based on when you join this study. Up to 4 groups of 3 participants will be enrolled in
Part 1, and up to 20 participants will be enrolled in Part 2.

If you are enrolled in Part 1, the dose of APX005M you receive will depend on when you join
this study. The first group of participants will receive the lowest dose level of APX005M.
Each new group will receive a higher dose of APX005M than the group before it, if no
intolerable side effects were seen. This will continue until the highest tolerable dose of
APX005M is found.

If you are enrolled in Part 2, you will receive APX005M at the highest dose that was
tolerated in Phase 1

All participants will receive the same dose level of pembrolizumab.

Study Drug Administration:

APX005M will be injected directly into 1 tumor every 3 weeks (Weeks 0, 3, 6, and 9) for up to
4 doses.

The injections may be done with or without the help of a ultrasound, CT, and MRI.

If the doctor thinks it is needed, you may need to stay in the hospital overnight or be
monitored by a caregiver for 24 hours after you receive APX005M.

You will receive pembrolizumab by vein 1 time every 3 weeks (Weeks 0, 3, 6, 9, and 12). The
first dose of pembrolizumab will be given 1-2 days before or after your first dose of
APX005M.

You will be given a diary to write down any injection site reactions you may have.

Study Visits:

Within 1 week before your first APX005M injection:

- You will have a physical exam.

- You will have a punch biopsy or image-guided biopsy of a tumor to check the status of
the disease. To collect a biopsy, the area of skin is numbed with anesthetic and a small
cut is made to remove all or part of the affected tissue. To collect a punch biopsy, the
area of skin is numbed with anesthetic and a small cut is made to remove all or part of
the affected tissue. To perform an image-guided biopsy, a needle is inserted into the
affected area using imaging such as CT or ultrasound to collect cells or tissue from an
organ, lymph node, or suspected tumor mass. The doctor will use the imaging to guide the
needle into the area.

- Blood (about 4½ tablespoons) will be drawn to test your immune system. If you can become
pregnant, blood (about 1 teaspoon) may be drawn for a pregnancy test or urine may be
collected to test for pregnancy.

- The tumors may be measured and photographed.

On Day 1 of Cycle 1:

- You will have a physical exam.

- Blood (about 5½ tablespoons) will be drawn for routine tests and test your immune
system.

- The tumor may be measured and photographed.

On Day 2 of Cycle 1:

- Your vital signs (blood pressure, heart rate, temperature, and breathing rate) will be
measured.

- Blood (about 1 teaspoon) will be drawn for routine tests.

- You will have a biopsy of one of the injected tumor sites within about 24 hours after
the 1st injection to check the status of the disease.

On Day 3 of Cycle 1:

- Your vital signs will be measured.

- Blood (about 5 tablespoons) will be drawn for routine tests and to test your immune
system.

On Days 8 and 15 of Cycle 1:

- Your vital signs will be measured.

- Blood (about 1½ teaspoons) will be drawn for routine tests.

- Blood (about 4½ tablespoons) may be drawn to test your immune system (Day 8 only).

On Day 1 of Cycle 2:

- You will have a physical exam.

- Blood (about 5½ tablespoons) will be drawn for routine tests and to test your immune
system.

On Days 8 and 15 of Cycle 2:

- Your vital signs will be measured.

- Blood (about 1½ teaspoons) will be drawn for routine tests.

- Blood (about 4½ tablespoons) may be drawn to test your immune system (Day 8 only).

On Day 1 of Cycle 3 (± 3 days):

- Your vital signs will be measured.

- You will have a physical exam.

- You will have a biopsy of one of the injected tumors and one of the tumors for which you
did not have an injection to check the status of the disease.

- The tumors may be measured and photographed.

- You will have CT, MRI/CT, and/or an ultrasound to check the status of the disease.

- Blood (about 2½ teaspoons) will be drawn for routine tests. If you can become pregnant,
a pregnancy test may be performed. Urine may be collected for the pregnancy test.

- Blood (about 4½ tablespoons) will be drawn to test your immune system.

On Day 1 of Cycle 4:

- Your vital signs will be measured

- You will have a physical exam.

- Blood (about 2½ teaspoons) will be drawn for routine tests

- Blood (about 4½ tablespoons) will be drawn to test your immune system.

On Day 1 of Cycles 5-8:

- Your vital signs will be measured.

- You will have a physical exam.

- Blood (about 1½ teaspoons) will be drawn for routine tests.

On Day 1 of Cycles 5 and 8 ONLY (± 3 days):

- Blood (about 1½ teaspoons) will be drawn for routine tests.

- Blood (about 4½ tablespoons) will be drawn to test your immune system.

- You may have a biopsy of one of the injected tumors and one of the tumors for which you
did not have an injection to check the status of the disease (Cycle 5 only).

- The tumors may be measured and photographed.

- You will have CT, MRI/CT, and/or an ultrasound to check the status of the disease.

Cycles beyond Cycle 8:

°You will have CT, MRI/CT, and/or an ultrasound to check the status of the disease (every 3
months for up to 2 years).

Length of Treatment:

You will be on study for up to 2 years. You will be taken off study if the disease gets
worse, if intolerable side effects occur, or if you are unable to follow study directions.

If your doctor thinks it is in your benefit, you may continue to receive pembrolizumab as
standard of care after you are off this study. Your doctor will describe this in more detail.

Off-Study Visit:

If you have to go off study early because the disease got worse or you had intolerable side
effects:

- Your vital signs will be measured.

- You will have a physical exam.

- Blood (about 1½ teaspoons) will be drawn for routine tests.

- Blood (about 4½ tablespoons) will be drawn to test your immune system.

Follow-Up:

Within 2 weeks after your last study drug dose and every 8-12 weeks after that, you may have
scans to check the status of the disease. Your doctor will decide what type of scans you will
have.

If you choose to seek care at another hospital, the study staff will call you every 3 months
for up to 2 years after your last study drug dose. You will be asked how you are doing. The
calls should last about 5 minutes.

Inclusion Criteria:

1. Be willing and able to provide written informed consent/assent for the trial.

2. Histologically or cytologically confirmed malignant melanoma from skin, or mucosal
melanoma (i.e. ocular melanoma subjects are not eligible)

3. Measurable, unresectable stage III (in transit lesions) or stage IVA, IVB, IVC disease

4. At least two injectable lesions (amenable for direct injection or through the use of
image guidance such ultrasound [US], CT or MRI) defined as any injectable cutaneous,
subcutaneous, nodal, or visceral melanoma lesion >/= 10 mm in longest diameter

5. Age >/= 18 years

6. ECOG performance status 0 or 1

7. Total bilirubin less than or equal to 2.0 mg/dl, except in patients with Gilbert's
Syndrome who must have a total bilirubin less than 3.0 mg/dl.

8. Platelet count greater than or equal to 100,000/mm^3

9. WBC >3000/mm^3

10. ANC>= 1500/mm^3

11. Hemoglobin >9 g/dL

12. Serum ALT and AST <3 the upper limit of normal (ULN); <5 ULN if there is liver
involvement secondary to the tumor

13. Serum creatinine
14. Seronegative for HIV antibody

15. Patients with a negative pregnancy test (urine or serum) must be documented within 14
days of screening for women of childbearing potential (WOCBP). A WOCBP has not
undergone a hysterectomy or who has not been naturally postmenopausal for at least 12
consecutive months (i.e. who has not had menses at any time in the preceding 12
consecutive months).

16. Unless surgically sterile by bilateral tubal ligation or vasectomy of partner(s), the
patient agrees to continue to use a barrier method of contraception throughout the
study and for 4 months after the last dose of APX005M or Pembrolizumab such as:
condom, diaphragm, hormonal, IUD, or sponge plus spermicide. Abstinence is an
acceptable form of birth control.

Exclusion Criteria:

1. Patients who have previously received pembrolizumab or PD-/L1 blockade therapy.
Adjuvant IFN-a, is allowed if last dose was received at least 6 months of starting
study treatment.

2. Active autoimmune disease requiring disease-modifying therapy.

3. Concurrent systemic steroid therapy higher than physiologic dose (>7.5 mg/day of
prednisone or equivalent).

4. Any form of active primary or secondary immunodeficiency.

5. Patients with history of hematologic malignancy.

6. Active coagulopathy.

7. History of New York Heart Association class 3-4 congestive heart failure or history
myocardial infarction within 6 months of starting study treatment.

8. History of arterial thrombosis within 3 months of starting study treatment.

9. History of clinically manifested CNS metastases, except if brain metastases have been
treated, are stable and are asymptomatic

10. Prior malignancy except the following: adequately treated basal cell or squamous cell
skin cancer, in-situ cervical cancer, thyroid cancer (except anaplastic) or any cancer
from which the patient has been disease-free for 2 years.

11. Subjects who have received prior immune checkpoint inhibitors (e.g., anti-PD-1,
anti-PD-L1), anti-CD40.

12. Subjects that have received experimental vaccines or other immune therapies should be
discussed with the Principal Investigator to confirm eligibility.

13. Active known clinically serious infections (> Grade 2 NCI-CTCAE version 4.03).

14. Prior systemic therapy, radiation therapy, or surgery within the 28 days of starting
study treatment. Palliative radiotherapy to a limited field or palliative cryoablation
is allowed after consultation with the Principal Investigator, at any time during the
study participation including screening.

15. Women of child-bearing potential (WOCBP), women who are pregnant, or women who are
nursing.