Phase 1/2 Dose-Escalation and Expansion Study of FLX475 Alone and in Combination with Pembrolizumab in Advanced Cancer

This clinical trial is a Phase 1/2, open-label, sequential-group, dose-escalation and cohort
expansion study to determine the safety and preliminary anti-tumor activity of FLX475 as
monotherapy and in combination with pembrolizumab.

The study will be conducted in 2 parts, a dose-escalation phase (Part 1) and a cohort
expansion phase (Part 2). In Part 1 of the study, subjects will be enrolled in sequential
cohorts treated with successively higher doses of FLX475 as monotherapy or in combination
with pembrolizumab. In Part 2 of the study, subjects will be initially enrolled in Stage 1 of
parallel expansion cohorts of FLX475 as monotherapy or in combination with pembrolizumab.

Inclusion Criteria:

- Documented advanced or metastatic cancer ineligible for standard therapies with one of
the following histologies

- Dose Escalation: non-small cell lung cancer, head and neck squamous cell
carcinoma, nasopharyngeal carcinoma, metastatic triple negative breast cancer,
urothelial carcinoma, gastric cancer, esophageal carcinoma, cervical cancer,
classical Hodgkin lymphoma

- Dose Expansion: nasopharyngeal carcinoma, lymphoma, head and neck squamous cell
carcinoma, cervical cancer, non-small cell lung cancer, triple-negative breast
cancer

- Eastern Cooperative Oncology Group (ECOG) Performance Status 0-1

- Evaluable disease at baseline (at least one measurable target lesion by imaging for
expansion cohorts)

- Tumor available for biopsy

Exclusion Criteria:

- History of allergy or severe hypersensitivity to biologic agents

- History of Grade 3-4 immune-related adverse events leading to discontinuation of prior
immuno-oncology treatment

- Active autoimmune disease or serious autoimmune disease within past 2 years requiring
systemic therapy

- History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced
pneumonitis, idiopathic pneumonitis, (non-infectious) pneumonitis that required
steroids, or symptoms of active pneumonitis

- Prior allogeneic hematopoietic stem cell transplant within 5 years, or prior
allogeneic organ transplant

- Active graft-versus-host disease