A Study Assessing KB707 for the Treatment of Locally Advanced or Metastatic Solid Tumors

Key Inclusion Criteria:

• Histologically confirmed diagnosis of a locally advanced or metastatic solid tumorand the individual has progressed on standard of care therapy, cannot toleratestandard of care therapy, refused standard of care therapy, or there is no standardof care therapy.

• Age 12 years or older at the time of informed consent

• Life expectancy >12 weeks

• ECOG performance status of 0 or 1

• Have measurable disease per RECIST v1.1 at Screening

• Cohorts 5 and 6 only: Histologically confirmed stage III (unresectable) or stage IVmelanoma, as per American Joint Committee on Cancer (AJCC) staging system (8thedition; AJCC 2017) and

1. Subject has previously failed one prior anti-PD-1/PD-L1 treatment (asmonotherapy or in combination with other checkpoint inhibitors such asanti-LAG-3 or anti-CTLA-4); and

2. If proto-oncogene B-Raf (BRAF) V600 mutation-positive, subject previouslyfailed a BRAF inhibitor or BRAF inhibitor in combination with mitogen-activatedextracellular signal-regulated kinase (MEK) inhibitor

• Cohort 5 only: Age 12 years or older at the time of informed consent

• Cohort 6 only: Age 18 years or older at the time of informed consent

Key Exclusion Criteria:

• Prior surgery or radiation therapy must be fully recovered, including all radiation -related toxicities and subject does not require systemic corticosteroids

• The subject is pregnant, nursing, or plans to become pregnant during study treatmentand through three months after the last dose of KB707

• Have known history of positive human immunodeficiency virus (HIV 1/2)

• Cohorts 5 and 6 only:

1. Subject has a known additional malignancy that is progressing or requiresactive treatment.

2. Subject has uveal/ocular melanoma.

3. The subject has active brain metastases or leptomeningeal metastases

4. Subject has received more than 2 lines of systemic therapy for unresectable ormetastatic melanoma

5. Prior anti-LAG-3 and/or anti-PD-1 therapy was intolerable and requireddiscontinuation of treatment