S*BIO's Novel JAK2 Inhibitor Pacritinib (SB1518) Effectively Reduces Splenomegaly in Myelofibrosis (MF) Patients With Minimal Impact on Existing Cytopenias Providing Important Therapeutic Niche In Treatment of MF

SINGAPORE, Dec. 12, 2011 /PRNewswire/ -- S*BIO Pte Ltd today announced that results from a Phase 2 study demonstrated that its JAK2 inhibitor pacritinib (SB1518) effectively reduced splenomegaly in myelofibrosis (MF) patients, with minimal impact on existing cytopenias providing an important therapeutic niche in the treatment of MF. Results were presented at the 53rd ASH Annual Meeting and Exposition in San Diego.

"Pacritinib is an active drug for the treatment of splenomegaly in patients with primary myelofibrosis, post-polycythemia vera-myelofibrosis and post-essential thrombocythemia-myelofibrosis regardless of baseline thrombocytopenia," said Rami S. Komrokji, M.D., principal author of the oral presentation. "The once daily dose of pacritinib was well tolerated with manageable gastrointestinal toxicity as the main side effect. The minimal impact on existing cytopenias in MF patients provides an important therapeutic outcome for pacritinib in the treatment of this patient population. The results support the rapid advancement of pacritinib into Phase 3 clinical trials to further support its safety and efficacy."

The primary endpoint of pacritinib's Phase 2 study was to assess the spleen response rate, defined as a >/=35% reduction in MRI-measured spleen volume between baseline and week 24. Thirty-four MF patients were enrolled in the study. The most common treatment-related adverse events were gastrointestinal, which were generally low grade and easily managed.  Pacritinib was equally well tolerated by patients with normal platelet counts and those with thrombocytopenia and anemia. Thirty patients (88%) showed reduction in palpable splenomegaly, 14 (41%) showed decreases of >/=50% and five (15%) achieved clinical resolution of splenomegaly. Eight patients (24%) had decreases in spleen volume by >/=35%.  Spleen response rates were equivalent among patients with low baseline platelet counts and those with normal baseline counts.  At the six-month visit, a significant reduction (>2 point improvement in mean symptom score) was observed for MF-associated symptoms, including abdominal pain, bone pain, early satiety, worst fatigue, inactivity, night sweats and pruritus.

"There is a significant medical need in the treatment of myelofibrosis and the results from pacritinib's clinical trials encourage us to quickly move forward with a global Phase 3 study to further demonstrate pacritinib's clinical benefits and consequently capture an important niche market in the treatment of MF," said Tamar Howson, interim CEO and board member of S*BIO.

Pacritinib is a small molecule JAK2-selective kinase inhibitor, which has demonstrated high potency in preclinical models against both the wild type JAK2 kinase and the JAK2 kinase with the V617F mutation. The V617F mutation is found in high frequencies in myeloproliferative disorders such as MF. It is estimated that approximately 50% of patients with MF possess the JAK2 mutation.

About S*BIO Pte Ltd

S*BIO is a privately-held biotech company focused on the clinical development of novel targeted small molecule drugs for the treatment of cancer with leading programs including kinases and histone deacetylases (HDAC). Pacritinib, or SB1518, S*BIO's potent and orally-active JAK2 inhibitor, entered the clinic in 2008 and has completed Phase 2 trials for MF. It has received orphan drug designation from the U.S. and the E.U. regulatory authorities. S*BIO's lead HDAC inhibitor, pracinostat (SB939), is currently in Phase 2 trials. S*BIO's SB1317, a novel multikinase inhibitor, is in Phase 1 trials and under a worldwide exclusive license with Tragara Pharmaceuticals, Inc. for its development and commercialization.

S*BIO has strong links with a network of medical oncologists in Asia Pacific and its investors include Bio*One Capital a subsidiary of EDBI (EDB Investments), Aravis Ventures, Mitsui Ventures, Novartis Bioventures and other international funds. More information about S*BIO can be found at www.sbio.com.

SOURCE S*BIO Pte Ltd