The purpose of this study is to find out if, and at what dose, NST-628 can safely treat solid cancers in patients who have no other treatment options left. NST-628 has been tested in animals and demonstrated some anti-tumor activity. This research study will be the first in which it will be given to humans and is experimental. “Experimental” means that the study drug has not been approved by any government authority responsible for the regulation of new medicines. This trial will explore what doses of NST-628 are safe and tolerable, as well as see whether NST-628 can slow the...