Platform Study of Novel Ruxolitinib Combinations in Myelofibrosis Patients

Core treatment phase Inclusion Criteria:

1. Subjects have diagnosis of primary myelofibrosis (PMF) according to the 2016 World Health Organization (WHO) criteria, or diagnosis of post-essential thrombocythemia (ET) (PET-MF) or post-polycythemia vera (PV) myelofibrosis (PPV-MF) according to the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) 2007 criteria
2. Palpable spleen of at least 5 cm from the left costal margin (LCM) to the point of greatest splenic protrusion or enlarged spleen volume of at least 450 cm3 per MRI or CT scan at baseline (a MRI/CT scan up to 8 weeks prior to first dose of study treatment can be accepted).
3. Have been treated with ruxolitinib for at least 12 weeks prior to first dose of study treatment
4. Are stable (no dose adjustments) on the prescribed ruxolitinib dose (between 5 and 25 mg twice a day (BID)) for ≥ 4 weeks prior to first dose of study treatment

Extension treatment phase inclusion criteria:

1. Signed consent for the extension treatment phase
2. ongoing in the core treatment phase
3. demonstrates clinical benefit of treatment in core treatment phase per investigator's assessment.

Core treatment phase Exclusion Criteria:

1. Not able to understand and to comply with study instructions and requirements.
2. Received any investigational agent for the treatment of MF (except ruxolitinib) within 30 days of first dose of study treatment or within 5 half-lives of the study treatment, whichever is greater
3. Peripheral blood blasts count of > 10%.
4. has documented severe hypersensitivity reactions/immunogenicity (IG) to a prior biologic product or Received a monoclonal antibody (Ab) or immunoglobulin-based agent within 1 year of screening in NIS793, crizanlizumab or sabatolimab arms, or in rineterkib or siremadlin arms within <=4 weeks of screening or <=5 half-lives whichever is shorter
5. Splenic irradiation within 6 months prior to the first dose of study drug
6. Received blood platelet transfusion within 28 days prior to first dose of study treatment.

Extension treatment phase Exclusion Criteria:

1. meets any of study treatment discontinuation criteria
2. current evidence of treatment failure per investigator, following treatment in core treatment phase
3. enrolled in another interventional study
4. evidence of non-compliance to study procedures or withdrew consent in core treatment phase
5. currently has unresolved toxicities for which study treatment has been interrupted in the core treatment phase
6. local access to alternative myelofibrosis treatment including those currently under investigation in clinical trials as assessed suitable in the opinion of the investigator.

Other protocol-defined Inclusion/Exclusion criteria may apply.