Myelofibrosis (MONDO:0044903) is a condition defined by partial or complete replacement of the bone marrow stroma by fibrous tissue. Three forms are described in this packet: a primary bone marrow lesion occurring as part of chronic myeloproliferative disorders (chronic idiopathic myelofibrosis); a manifestation of acute myeloid leukemia (acute panmyelosis with myelofibrosis); and a secondary phenomenon due to bone marrow involvement by metastatic tumor, such as metastatic breast carcinoma. No germline gene associations are listed in this packet, consistent with the predominantly acquired pathophysiology of this condition.

Phenotype data are not available in this packet for myelofibrosis. The clinical characterization of this condition in the packet is limited to its pathological basis of bone marrow stromal fibrosis and its three primary disease forms.

The defining pathological process is replacement of the normal bone marrow stroma with fibrous tissue. This can arise in the context of chronic myeloproliferative disorders, as a feature of acute myeloid leukemia presenting as acute panmyelosis with myelofibrosis, or secondary to metastatic tumor infiltration of the bone marrow. No inherited gene associations are catalogued in this packet.

Diagnostic characterization is not detailed in this packet beyond the pathological basis of bone marrow stromal fibrosis. The condition spans primary and secondary etiologies, which are distinguished by clinical context as described in the definition.

Two pharmacological agents have received regulatory approval for myelofibrosis. Ruxolitinib (brand name JAKAFI) was approved in November 2011 and maintains active market status. Pacritinib (brand name VONJO) was approved in February 2022 and also maintains active market status. Neither agent is classified as gene therapy. Ten additional compounds hold orphan drug designation without approval, including bomedemstat, imetelstat, momelotinib, navitoclax, luspatercept, and flonoltinib, reflecting an active investigational pipeline.

Prognosis data are not available in this packet for myelofibrosis beyond the characterization of the condition as a bone marrow disorder with primary and secondary forms that vary in etiology and clinical context.

Ten clinical trials for myelofibrosis are active or recently recruiting across diverse investigational approaches. The ten orphan drug designations in this packet reflect broad pharmaceutical interest in novel therapeutic strategies for this condition.