This study is being done to find out if SEA-CD40 is safe and effective when given alone, in
combination with pembrolizumab, and in combination with pembrolizumab, gemcitabine, and
nab-paclitaxel. The study will test increasing doses of SEA-CD40 given at least every 3 weeks
to small groups of patients. The goal is to find the highest dose of SEA-CD40 that can be
given to patients that does not cause unacceptable side effects. Different dose regimens will
be evaluated. Different methods of administration may be evaluated. The pharmacokinetics,
pharmacodynamic effects, biomarkers of response, and antitumor activity of SEA-CD40 will also
be evaluated.