Mivebresib

Myelofibrosis (MF) is a bone marrow illness that affects blood-forming tissues in the body. MF disturbs the body's normal production of blood cells, causing extensive scarring in the bone marrow. This leads to severe anemia, weakness, fatigue, and an enlarged spleen. The purpose of this study is to see how safe and tolerable mivebresib is, when given alone, and in combination with navitoclax or ruxolitinib, for adult participants with MF.
Mivebresib is an investigational drug being developed for the treatment of MF. The study has 4 segments - A, B, C, and D. In Segment A, the safe dosing regimen of mivebresib is identified, and then given alone as monotherapy. In Segment B, C, and D, combination therapies of mivebresib with either ruxolitinib or navitoclax are given. Adult participants with a diagnosis of MF will be enrolled. Around 130 participants will be enrolled in 60 sites worldwide.
In Segment A, participants will receive different doses and schedules of oral mivebresib tablet to identify a safe dosing regimen. Additional participants will be enrolled at the identified monotherapy dosing regimen. In Segment B, participants will receive oral ruxolitinib and mivebresib will be given as "add-on" therapy. In Segment C, participants will receive mivebresib and oral navitoclax. In Segment D, participants will receive mivebresib and ruxolitinib. Participants will receive treatment until disease progression or the participants are not able to tolerate the study drugs.
There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the study at a hospital or clinic. The effect of treatment will be checked by medical assessments, blood and bone marrow tests, checking for side effects, and completing questionnaires.