On June 12, 2015 CTI BioPharma and Baxter International reported new patient-reported outcome (PRO) data for pacritinib – an investigational oral multikinase inhibitor with specificity for JAK2 and FLT3 – from the Phase 3 PERSIST-1 study (Press release, CTI BioPharma, JUN 12, 2015, View Source;p=RssLanding&cat=news&id=2058786 [SID:1234505405]). As recently reported at the American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) annual meeting, results show a significant reduction in the Total Symptom Score (TSS) (the proportion of patients with a 50 percent or greater reduction in TSS from baseline to Week 24), and in each individual common disease-related symptom, from baseline to Week 24, in patients treated with pacritinib compared to best available therapy (exclusive of a JAK inhibitor) (BAT). These PROs, as well as other quality of life measures, will be presented at the 20th Congress of European Hematology Association (EHA) (Free EHA Whitepaper) by Adam Mead, M.D., Guy’s and St. Thomas’ NHS Foundation Trust, Guy’s Hospital, London, United Kingdom in an oral presentation on Sunday, June 14, 2015 at 12:15 CEST (abstract #LB2072). These data were also selected for inclusion in the official EHA (Free EHA Whitepaper) Press Briefing which occurred today (Friday, June 12, 2015) at 08:30 CEST. As previously reported, the PERSIST-1 trial met its primary endpoint of spleen volume reduction of 35 percent or greater from baseline to Week 24 as measured by MRI/CT scan.
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Myelofibrosis is a rare blood cancer associated with significantly reduced quality of life and shortened survival. As the disease progresses, the body slows production of important blood cells and within one year of diagnosis the incidence of disease-related thrombocytopenia (very low blood platelet counts), severe anemia, and red blood cell transfusion requirements increases significantly. Among other complications, most patients with myelofibrosis present with enlarged spleens (splenomegaly), as well as many other potentially devastating physical symptoms such as abdominal discomfort, bone pain, feeling full after eating little, severe itching, night sweats, and extreme fatigue.
"Patient-reported outcomes are an important measure for understanding the potential benefit of a therapy on patients’ lives – particularly for a disease such as myelofibrosis where the symptoms have such a tremendous impact on the quality of patients’ daily lives," stated James A. Bianco, M.D., President and CEO of CTI BioPharma. "These new data from the PERSIST-1 study further support our belief, not only in the activity of pacritinib, but also the potential to positively impact patients’ daily lives by relieving the symptoms that accompany myelofibrosis."
"The PERSIST-1 trial has continued to generate positive and important findings for the hematology community," said David Meek, Head of Oncology at Baxter BioScience. "We look forward to advancing the clinical trial program of pacritinib as we work to realize the full potential of this investigational compound to help patients with serious blood cancers, such as myelofibrosis."
Study Details and Findings Presented at EHA (Free EHA Whitepaper)
PERSIST-1 is a randomized (2:1), controlled Phase 3 registration-directed trial comparing the efficacy and safety of pacritinib to BAT – which included a range of currently utilized off-label treatments – in 327 patients with myelofibrosis, regardless of the patients’ platelet counts. As previously reported at ASCO (Free ASCO Whitepaper), the trial met its primary endpoint of spleen volume reduction (35 percent or greater reduction from baseline to Week 24 by MRI/CT scan) in the intent-to-treat (ITT) population; these results included patients with severe or life-threatening thrombocytopenia. The study also measured patient-reported outcomes (PROs), the proportion of patients with a 50 percent or greater reduction in TSS from baseline to Week 24, which have become important for approval of new therapies and was one of the secondary endpoints of the study. As previously reported, patients treated with pacritinib experienced greater improvement in their disease-related symptoms (ITT patient population: 24.5 percent of pacritinib-treated patients vs 6.5 percent of BAT-treated patients, p<0.0001; evaluable patient population: 40.9 percent of pacritinib-treated patients vs 9.9 percent of BAT-treated patients, p<0.0001).
New data presented at EHA (Free EHA Whitepaper), which included results from multiple PROs measurement tools, showed:
Myeloproliferative Neoplasm Symptom Assessment (MPN-SAF TSS and MPN-SAF TSS 2.0)
When using the MPN-SAF TSS and MPN-SAF TSS 2.0, each of the six common disease-related symptoms from the TSS results showed improvements in abdominal discomfort (46 percent improvement with pacritinib vs no improvement with BAT); bone pain (32 percent improvement with pacritinib vs 8 percent improvement with BAT); feeling of early fullness (45 percent improvement with pacritinib vs 1 percent worsening with BAT); itching (48.5 percent improvement with pacritinib vs 10 percent improvement with BAT); night sweats (69.5 percent improvement with pacritinib vs no improvement with BAT); and fatigue (27.5 percent improvement with pacritinib vs 4 percent worsening with BAT). MPN-SAF TSS and MPN-SAF TSS 2.0 are specific sets of questions patients answer daily (via electronic diary) and which are based on a questionnaire originally developed by Ruben A. Mesa, M.D., Deputy Director of the Mayo Clinic Cancer Center in Scottsdale, Arizona, USA.
Patient Global Impression of Change (PGIC)
Based on the PGIC assessment – which measures a patient’s assessment of overall health on a 7-point scale ranging from "very much worse" to "very much improved" – approximately 80 percent of evaluable patients treated with pacritinib rated their condition as improved compared to approximately 20 percent with BAT.
European Organization for Research and Treatment of Cancer Quality-of-Life 30 Questionnaire (EORTC QLQ-C30)
A greater improvement was also reported by evaluable patients treated with pacritinib vs BAT across all components of the EORTC QLQ-C30 questionnaire, a well-validated measure of quality of life in cancer patients.
The most common adverse events occurring with pacritinib within 24 weeks, of any grade, were mild to moderate diarrhea (53.2 percent vs 12.3 percent with BAT), nausea (26.8 percent vs 6.6 percent with BAT), anemia (22.3 percent vs 19.8 percent with BAT), thrombocytopenia (16.8 percent vs 13.2 percent with BAT), and vomiting (15.9 percent vs 5.7 percent with BAT). Of the patients treated with pacritinib, 3 discontinued therapy and 13 patients required dose interruption (average one week) for diarrhea. Patients received a daily full dose of pacritinib over the duration of treatment. Gastrointestinal symptoms typically lasted for approximately one week and few patients discontinued treatment due to side effects. There were no Grade 4 gastrointestinal events reported.
About Pacritinib
Pacritinib is an investigational oral multikinase inhibitor with specificity for JAK2 and FLT3. The JAK family of enzymes is a central component in signal transduction pathways, which are critical to normal blood cell growth and development, as well as inflammatory cytokine expression and immune responses. Mutations in these kinases have been shown to be directly related to the development of a variety of blood-related cancers, including myeloproliferative neoplasms, leukemia, and lymphoma.
About Myelofibrosis
Myelofibrosis is a serious and life-threatening chronic blood cancer caused by the accumulation of malignant bone marrow cells that triggers an inflammatory response and scars the bone marrow. The replacement of bone marrow with scar tissue limits its ability to produce red blood cells, prompting the spleen and liver to take over this function. Symptoms that arise from this disease include enlargement of the spleen, anemia, extreme fatigue, and pain. Myelofibrosis is a one of three main types of myeloproliferative neoplasms (MPN), which are a closely related group of hematological blood cancers.1 The estimated prevalence of MPNs suggest there are approximately 300,000 people living with the disease in the U.S. of which myelofibrosis accounts for approximately 18,000 patients.2 In Europe, there is a wide variation of prevalence observed across data sources. Myelofibrosis has a median age of 64 at the time of diagnosis2 and is a progressive disease with approximately 20 percent of patients eventually developing acute myeloid leukemia.3 The median survival for high-risk patients is less than one and a half years; median survival for myelofibrosis patients overall is approximately six years.4
About the PERSIST Phase 3 Development Program of Pacritinib
Pacritinib is currently being evaluated in two Phase 3 clinical trials, known as the PERSIST program, for patients with myelofibrosis. PERSIST-1 is a randomized (2:1), open-label, multinational Phase 3 clinical trial comparing the efficacy and safety of pacritinib with that of BAT, in 327 enrolled patients with primary and secondary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (PPV-MF), or post-essential thrombocythemia myelofibrosis (PET-MF), without exclusion for low platelet counts. PERSIST-2 is a randomized (2:1), open-label, multinational Phase 3 clinical trial evaluating pacritinib compared to BAT, including the approved JAK1/JAK2 inhibitor dosed according to product label for patients with myelofibrosis whose platelet counts are less than or equal to 100,000 per microliter. The trial is designed to enroll up to 300 patients in North America, Europe, Australia, New Zealand, and Russia.
Additional details are available at www.clinicaltrials.gov or www.PERSISTprogram.com.
CTI BioPharma and Baxter BioScience, which is expected to become Baxalta Incorporated in mid-2015, entered into a worldwide license agreement in November 2013 to develop and commercialize pacritinib. CTI BioPharma and Baxter will jointly commercialize pacritinib in the U.S. while Baxter has exclusive commercialization rights for all indications outside the U.S.