Development Pipeline

Development Pipeline

Sierra Oncology is a late stage drug development company focused on advancing targeted therapeutics for the treatment of patients with significant unmet medical needs in hematology and oncology.

Momelotinib, our lead drug candidate, is a potent, selective and orally-bioavailable JAK1, JAK2 & ACVR1 inhibitor with a differentiated therapeutic profile in myelofibrosis encompassing robust constitutional symptom improvements, a range of meaningful anemia benefits, including eliminating or reducing the need for frequent blood transfusions, and comparable spleen control to ruxolitinib. More than 1,200 subjects have received momelotinib since clinical studies began in 2009, including more than 800 patients treated for myelofibrosis.

Chronic, progressive anemia is a key hallmark of myelofibrosis and transfusion dependence is the most important negative prognostic indicator of reduced survival in this disease. Approximately 60% of patients are anemic and 45% are transfusion dependent within one year of diagnosis, with most patients ultimately progressing to transfusion dependency. Unfortunately, currently approved JAK inhibitor therapies can induce or worsen anemia, exacerbating this significant unmet medical need in anemic myelofibrosis patients.

The marked systemic inflammation seen in myelofibrosis leads to increased ACVR1 activity which in turn increases secretion of hepcidin, resulting in perturbed iron homeostasis and an iron-restricted anemia. Momelotinib’s inhibition of ACVR1 in addition to JAK1 and JAK2, unique amongst the JAK inhibitor class, results in notable reductions of both hepcidin and inflammation, restoring iron homeostasis and RBC production, thereby alleviating anemia and transfusion dependency.

Momelotinib is an investigational drug that is not approved for any use in any country. The U.S. Food and Drug Administration has granted Fast Track designation to momelotinib for the treatment of patients with intermediate/high-risk myelofibrosis who have previously received a JAK inhibitor. Momelotinib is wholly owned by Sierra Oncology and is protected by patents anticipated to provide potential exclusivity to 2040 in the United States and Europe (including Patent Term Extension or Supplementary Protection Certificate).

Sierra is also developing a portfolio of DNA Damage Response (DDR) assets, consisting of SRA737 and SRA141, and is conducting a campaign intended to seek non-dilutive strategic options to support their further advancement. SRA737 is a potent, highly selective, orally bioavailable small molecule inhibitor of Checkpoint kinase 1 (Chk1), a key regulator of cell cycle progression and the DDR network, and has demonstrated preliminary clinical efficacy. SRA141 is a potent, selective, orally bioavailable small molecule inhibitor of Cell division cycle 7 kinase (Cdc7) with a potential novel mechanism of cytotoxicity, and has successfully completed the IND process with the FDA enabling the commencement of clinical trials. Sierra retains the global commercialization rights to SRA737 and SRA141.