Additional Study Information: The purpose of the study is to determine an appropriate dose of KRT-232 in combination TL-895 or KRT-232 alone for treatment of myelofibrosis (MF). There are 2 parts planned for this study, the Phase 1b that will test different doses of TL-895 given with KRT-232 and it will also test KRT-232 alone, to identify the recommended dose for Phase 2. The Phase 2 (expansion) will continue to test TL-895 at the recommended dose with KRT-232 to determine if it is a tolerable and effective treatment for MF. If you are participating in this study because it is difficult to tolerate a JAK inhibitor, both Part 1 (Phase 1b) and Part 2 (Phase 2) will test if KRT-232 alone can treat your MF. You are being asked to participate in this study because you have been diagnosed with MF and either your current treatments for MF have failed or have not been effective enough, or your current Janus Associated Kinase (JAK) Inhibitor treatment is not well-tolerated.