Momelotinib Oral Presentation at European Hematology Association Demonstrates Association Between Transfusion Independence and Improved Overall Survival

—Additional poster presentation highlights improved transfusion independence of momelotinib irrespective of baseline degree of anemia, platelet count or transfusion status—

SAN MATEO, Calif., June 11, 2021 /PRNewswire/ - Sierra Oncology, Inc. (SRRA), a late-stage biopharmaceutical company on a quest to deliver targeted therapies that treat rare forms of cancer, today announced data presented at the European Hematology Association (EHA) Annual Meeting highlighting transfusion independence with momelotinib is associated with improved overall survival, including in patients with anemia at baseline. In addition, transfusion independence is seen irrespective of baseline degree of anemia, platelet count or transfusion status.

"Momelotinib has previously been shown to provide an anemia benefit for myelofibrosis patients, resulting in higher rates of transfusion independence. The data presented at EHA are particularly exciting because they suggest myelofibrosis patients randomized to momelotinib who achieve or maintain transfusion independence at Week 24 achieve a clinically relevant improvement in overall survival, the gold standard measurement of oncology treatment.," said Barbara Klencke, MD, Chief Medical Officer at Sierra Oncology. "The correlation between Week 24 transfusion independence response and overall survival observed with momelotinib is unique among JAK inhibitors.  This suggests that the likelihood of achieving or maintaining transfusion independence may become an important consideration for physicians when recommending myelofibrosis treatment options. With this in mind, we wanted to understand which patients were most likely to maintain or achieve transfusion independence by Week 24. In other data presented at EHA, we report observing higher rates of transfusion independence with momelotinib relative to ruxolitinib, regardless of a patient's baseline degree of anemia, platelet count or transfusion status."

Transfusion Independence is Associated with Improved Overall Survival in Myelofibrosis Patients Receiving Momelotinib

Efficacy data examining the association between transfusion independence and overall survival for momelotinib patients from SIMPLIFY-1 (JAKi-naïve) and SIMPLIFY-2 (JAKi-exposed) were presented in an oral presentation by Ruben Mesa, MD, Director of the Mays Cancer Center, UT Health San Antonio, MD Anderson Cancer Center. Previously published data demonstrated higher transfusion independence response rates in the momelotinib arms of SIMPLIFY-1 (67% vs. 49%) and SIMPLIFY-2 (43% vs. 21%) compared with ruxolitinib or best available therapy, respectively. Additionally, robust overall survival was observed with extended momelotinib treatment in both JAKi-naïve and JAKi-exposed patients (median not yet reached in SIMPLIFY-1 and 34.3 months in SIMPLIFY-2) as reported at ASH 2020. These new analyses being presented at EHA 2021 suggest JAKi-naïve patients receiving momelotinib achieve or maintain transfusion independence (TI) at Week 24 have favorable overall survival compared to non-responders, with a similar trend observed in SIMPLIFY-2.

Key Data Presented

• In SIMPLIFY-1 (JAKi-naïve patients)
• Patients randomized to momelotinib who were TI responders show a three-year overall survival of 80% compared to 50% for non-responders (HR=0.30; p<0.0001)
• Patients with anemia at baseline (RBC transfusion <12 weeks before baseline, or baseline Hgb <10 g/dL) show a similar survival advantage for momelotinib patients who achieve a TI response at Week 24 compared to TI non-responders (HR=0.32; p=0.0006)
• In SIMPLIFY-2 (JAKi-exposed patients)
• Patients randomized to momelotinib who were TI responders at Week 24 show a trend toward better OS compared to TI non-responders (HR=0.52; p=0.0652)

Improved Transfusion Independence Rates for Momelotinib vs. Ruxolitinib in Anemic JAKi Naïve Myelofibrosis Patients Independent of Baseline Platelet or Transfusion Status

Progressive anemia is a common occurrence in myelofibrosis, with nearly all patients requiring transfusions as their disease advances. As noted in the EHA oral presentation, JAKi-naïve patients receiving momelotinib who maintain or achieve transfusion independence at Week 24 have favorable overall survival compared to non-responders, with a similar trend observed in SIMPLIFY-2.

Data presented in a poster presentation by Jean-Jacques Kiladjian, MD, PhD, Professor of Clinical Pharmacology, Paris Diderot University and Consultant Hematologist and Head of the Clinical Investigation Center, Saint Louis Hospital, show that the prognostically important Week 24 TI rates in JAKi-naïve myelofibrosis patients were consistently higher in anemic patients receiving momelotinib compared to ruxolitinib in all patient subsets with baseline hemoglobin <14 g/dL and all subsets defined by baseline platelet count and baseline transfusion status. Combined with data from the oral presentation, these data suggest the goal of achieving TI should become an important driver of treatment decisions in myelofibrosis.

About Sierra Oncology
Sierra Oncology is a late-stage biopharmaceutical company on a quest to deliver targeted therapies that treat rare forms of cancer. We harness our deep scientific expertise to identify compounds that target the root cause of disease. Our team takes an evidence-based approach to understand the limitations of current treatments and explore new ways to change the cancer treatment paradigm. Together we are transforming promise into patient impact.

For more information, visit www.SierraOncology.com.

Cautionary Note on Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995, including, but not limited to, statements regarding Sierra Oncology's expectations regarding the commercialization and future success of momelotinib and future expansion of its pipeline. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. These statements are based on management's current expectations and beliefs and are subject to a number of risks, uncertainties and assumptions that could cause actual results to differ materially from those described in the forward-looking statements. Such forward-looking statements are subject to risks and uncertainties, including, among others, the risk that Sierra Oncology's cash resources may be insufficient to fund its current operating plans and it may be unable to raise additional capital when needed, the risk that disruptions and impacts of COVID-19 will be significant and lengthy, Sierra Oncology may be unable to successfully develop and commercialize momelotinib, momelotinib may not demonstrate safety and efficacy or otherwise produce positive results, Sierra Oncology may experience delays in the clinical development of momelotinib, Sierra Oncology may be unable to acquire additional assets to build a pipeline of additional product candidates, Sierra Oncology's third-party manufacturers may cause its supply of materials to become limited or interrupted or fail to be of satisfactory quantity or quality, Sierra Oncology may be unable to obtain and enforce intellectual property protection for its technologies and momelotinib and the other factors described under the heading "Risk Factors" set forth in Sierra Oncology's filings with the Securities and Exchange Commission from time to time. Sierra Oncology undertakes no obligation to update the forward-looking statements contained herein or to reflect events or circumstances occurring after the date hereof, other than as may be required by applicable law.

View original content:http://www.prnewswire.com/news-releases/momelotinib-oral-presentation-at-european-hematology-association-demonstrates-association-between-transfusion-independence-and-improved-overall-survival-301310474.html

SOURCE Sierra Oncology