CTI BioPharma Announces Outcome From End-of-Phase-2a Meeting With U.S. Food and Drug Administration (FDA) Regarding Pacritinib for Treatment of Myelofibrosis
"We are pleased to be able to move the pacritinib program forward and are now in the process of finalizing an amendment to the PAC203 protocol, which the
The randomized, open-label Phase 2 PAC203 dose-finding study was designed to evaluate the safety and efficacy of three dosing regimens of oral pacritinib in 150 patients with myelofibrosis. The Company expects topline safety and efficacy results from the Phase 2 portion of the PAC203 study in the third quarter of 2019 and is targeting presentation of the Phase 2 results at a scientific conference before the end of 2019.
The previous Phase 3 PERSIST program consisted of the PERSIST-1 trial, which was conducted in a broad set of patients without limitations on platelet counts, and the PERSIST-2 trial, which was conducted in patients with low platelet counts. An ad-hoc analysis of pooled data from PERSIST-1 and PERSIST-2 evaluated results from patients with platelet counts of less than 50,000 per microliter and showed that 23% (n=104) of patients administered pacritinib had a ≥35% spleen volume reduction (SVR), compared to 2% (n=48) (p=0.0007) given the best available therapy, which in the PERSIST-1 trial excluded JAK2 inhibitors and in the PERSIST-2 trial included the approved JAK2 inhibitor, ruxolitinib. The most common treatment-emergent adverse events of any grade occurring in 20% or more of patients treated with pacritinib within 24 weeks during the PERSIST-1 and PERSIST-2 trials were gastrointestinal (generally manageable diarrhea, nausea and vomiting) and hematologic (anemia and thrombocytopenia).
The Company is currently amending the protocol for the ongoing Phase 2 PAC203 study to include the new PACIFICA Phase 3 portion, in which CTI intends to compare the safety and efficacy of 200 mg of pacritinib administered twice daily to Physician's Choice in 180 myelofibrosis patients with severe thrombocytopenia (platelet counts of less than 50,000 per microliter) at approximately 120 sites worldwide. Patients will be randomized in a ratio of 2:1 between pacritinib and Physician's Choice. The primary endpoint of the trial is the percentage of patients who achieve at least 35% reduction in spleen volume at week 24. Dr. Srdam Verstovsek, Professor,
About Myelofibrosis and Severe Thrombocytopenia
Myelofibrosis is a type of bone marrow cancer that results in formation of fibrous scar tissue and can lead to severe anemia, weakness, fatigue and an enlarged spleen and liver. Patients with severe thrombocytopenia are estimated to make up more than one-third of patients treated for myelofibrosis, or approximately 18,000 people.1 Severe thrombocytopenia, defined as blood platelet counts of less than 50,000 per microliter, has been shown to result in overall survival rates of just 15 months.2 Thrombocytopenia in patients with myelofibrosis is associated with the underlying disease but has also been shown to correlate with treatment with ruxolitinib, currently the only approved treatment for myelofibrosis, which can lead to dose reductions and as a result may potentially reduce clinical benefit. Survival in patients who have discontinued ruxolitinib therapy is further compromised, with an average overall survival of seven to 14 months.3,4 There are currently no approved therapies available to treat myelofibrosis patients with severe thrombocytopenia, or patients who have failed ruxolitinib treatment, thereby making this a significant unmet medical need.
Pacritinib is an investigational oral kinase inhibitor with specificity for JAK2, FLT3, IRAK1 and CSF1R. 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. In addition to myelofibrosis, the kinase profile of pacritinib suggests its potential therapeutic utility in conditions such as acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia (CMML), and chronic lymphocytic leukemia (CLL), due to its inhibition of c-fms, IRAK1, JAK2 and FLT3.
About CTI BioPharma Corp.
This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 and the Private Securities Litigation Reform Act of 1995. These forward-looking statements include statements regarding our expectations about: our ability to commence the PACIFICA Phase 3 trial of pacritinib; the anticipated trial design and enrollment of the PACIFICA Phase 3 trial; the effectiveness of, and potential changes to, the PACIFICA Phase 3 trial design; the timing of and results from clinical trials and other development activities related to pacritinib, including the anticipated PACIFICA Phase 3 trial and its related protocol; the potential efficacy, safety profile, future development plans, addressable market, regulatory success and commercial potential of pacritinib; the anticipated timing of regulatory submissions and interactions, including
1 Company estimates based on:
2 Masarova et al., Eur J Haematolol. 2017
3 Newberry, Blood 2017
4 Mehra, et al. ASH 2016 poster, Abstract 4769
CTI BioPharma Investor Contacts:
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