Grapiprant and Pembrolizumab in Patients With Advanced or Progressive MSS Colorectal Cancer

Key Inclusion Criteria:

- Male and female adult patients 18 years of age or older on day of signing informed
consent.

- Patients must have a histologically confirmed advanced, metastatic, or progressive
Microsatellite Stable (MSS) Colorectal Cancer (CRC) per institutional standards.

- Patient has received at least two prior lines of therapy for advanced or metastatic
CRC, at least one of which included fluorouracil.

- Highly effective birth control.

- Measurable disease.

- Accessible tumor that can be safely accessed for multiple core biopsies and patient is
willing to provide tissue from newly obtain biopsies before and during treatment.

- Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1.

- Be able to swallow and absorb oral tablets.

- Adequate organ function.

Key Exclusion Criteria:

- Prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an agent
directed to another stimulatory or co-inhibitory T-cell receptor

- Current use of NSAIDs, COX-2 inhibitors.

- History of severe hypersensitivity reactions to chimeric or humanized antibodies.

- Diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in
dosing exceeding 10 mg daily of prednisone equivalent) or any other form of
immunosuppressive therapy within 7 days prior the first dose of study drug.

- Known additional malignancy that is progressing or has required active treatment
within the past 3 years.

- Known active CNS metastases and/or carcinomatous meningitis.

- Active autoimmune disease that has required systemic treatment in past 2 years.

- History of non-infectious pneumonitis that required steroids or has current
pneumonitis.

- Active infection requiring systemic therapy.

- Recent (within the last 12 months) or current GI ulcer, colitis or non-immune colitis.

- Known history of human immunodeficiency virus (HIV) infection, Hepatitis B, or
Hepatitis C virus infection.

- Clinically significant (i.e. active) cardiovascular disease

- Medical conditions requiring concomitant administration of strong CYP3A4 or P
glycoprotein inhibitors or inducers.