Jan 25 (Reuters) - Sierra Oncology Inc said on Tuesday its experimental drug for anemic patients with a type of bone marrow cancer met the main goal of reducing disease symptoms and also cut patients' dependence on blood transfusions, in a late-stage trial.

The company acquired https://www.prnewswire.com/news-releases/sierra-oncology-acquires-momelotinib-an-investigational-janus-kinase-jak-12-and-activin-receptor-type-1-acvr1-inhibitor-for-myelofibrosis-from-gilead-sciences-300700644.html the drug, momelotinib, from Gilead Sciences Inc in 2018 for $198 million including milestone payments. It belongs to a class of anti-inflammatory treatments called JAK inhibitors, such as Incyte Corp's Jakafi.

Sierra said momelotinib is the first and only JAK inhibitor to demonstrate positive data on reducing symptoms, anemia and enlargement of a blood-filtering organ called spleen, all key hallmarks of the condition called myelofibrosis.

Myelofibrosis disrupts the body's production of blood cells, often causing severe anemia or a deficiency of red blood cells. People with anemia rely on periodic blood transfusions to improve their red blood cell count.

Current drugs only address symptoms and enlarged spleen, but can suppress bone marrow activity and thereby worsen anemia, the company said.

"Half of all myelofibrosis patients present with anemia at diagnosis and virtually all become anemic over time," said Ruben Mesa, co-principal investigator of the study.

Momelotinib was more effective in reducing patient dependence on blood transfusions than the control group in the study, which enrolled 195 patients previously treated with an approved JAK inhibitor, Sierra said.

The company, which said that full data from the clinical trial will be presented at an upcoming medical meeting, will file for marketing approval of momelotinib in the United States in the second quarter of this year. (Reporting by Manojna Maddipatla in Bengaluru; Editing by Vinay Dwivedi)