Inclusion Criteria:

          -  Relapsed, locally-advanced or metastatic colorectal or pancreatic cancer, squamous
             NSCLC, or SCCHN patients who are not candidates for standard therapy.

          -  All patients must have experienced disease progression on or after their most recent
             systemic therapy.

          -  Baseline measurable disease as measured by RECIST v1. 1.

          -  Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1.

          -  Colorectal cancer patients must have received prior therapy with each of following
             agents, if eligible: a fluoropyrimidine, oxaliplatin, irinotecan, and/or bevacizumab.
             Patients should have received no more than 3 systemic regimens in the metastatic
             setting.

          -  Patients with NSCLC must have predominant squamous histology. Patients must have
             received prior therapy with a platinum-based treatment and a checkpoint inhibitor
             (CPI), if eligible. Patients should have received no more than 2 systemic regimens in
             the metastatic setting.

               -  Patients eligible for a tyrosine kinase inhibitor should have received such
                  therapy. These patients should have received no more than 3 systemic regimens in
                  the metastatic setting.

          -  Patients with exocrine pancreatic adenocarcinoma must have predominant adenocarcinoma
             histology. Patients must have received prior therapy with a gemcitabine-based or
             5FU-based regimen, if eligible, and should have received no more than 1 systemic
             regimen in the unresectable or metastatic setting.

          -  Patients with SCCHN must have received prior therapy with a platinum-based regimen and
             a checkpoint inhibitor (CPI), if eligible, and should have received no more than 3
             systemic regimens in the recurrent/metastatic setting.

        Exclusion Criteria:

          -  Active bleeding conditions

          -  Ocular surface disease at the time of enrollment (Note: cataract is not considered
             active ocular surface disease for this protocol)

          -  Pulmonary disease requiring chronic medical therapy, unrelated to underlying cancer

          -  Uncontrolled tumor-related pain

          -  Peripheral neuropathy greater than or equal to Grade 2

          -  History of another malignancy within 3 years of the first dose of study drug, or any
             evidence of residual disease from a previously diagnosed malignancy.

          -  Active brain metastasis