Study of TL-895 Combined With Ruxolitinib in JAKi Treatment-Naïve MF Subjects and Subjects With MF Who Have a Suboptimal Response to Ruxolitinib

Inclusion Criteria: Subjects with suboptimal response to ruxolitinib:

• Treatment with at a stable dose of ruxolitinib prior to study entry
• Subjects ≥ 18 years of age and able to provide informed consent.
• Confirmed diagnosis of PMF, post-PV MF, or post-ET MF, as assessed by treatingphysician according to the World Health Organization (WHO) criteria
• High-risk, intermediate-2 risk, or intermediate-1 risk, defined by DynamicInternational Prognostic System (DIPSS)
• Palpable spleen measuring ≥ 5 cm below the left lower coastal margin (LLCM) or spleenvolume of ≥ 450 cm3 by MRI or CT scan assessment
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2
• Adequate hematological, hepatic, & renal function.

Exclusion Criteria: Treatment-naive subjects:

• Prior treatment with any JAKi Subjects with suboptimal response to ruxolitinib:
• Documented disease progression while on ruxolitinib treatment All subjects:
• Prior splenectomy or splenic irradiation within 24 weeks prior to first dose of studytreatment
• Prior treatment with a BTK or BMX inhibitor