NEW YORK, Dec. 10, 2019 (GLOBE NEWSWIRE) -- Stemline Therapeutics, Inc. (Nasdaq: STML), a commercial-stage biopharmaceutical company focused on the development and commercialization of novel oncology therapeutics, presented data from ELZONRIS® (tagraxofusp) Phase 1/2 clinical trials in myelofibrosis (oral presentation) and multiple myeloma, at the 2019 ASH annual meeting. The presentations are now available on the Stemline website, www.stemline.com, under the Scientific Presentations tab. Highlights of results are presented below.
Myelofibrosis: Clinical Trial of ELZONRIS in Patients with Intermediate or High-Risk, Relapsed/Refractory Myelofibrosis (MF) – Oral presentation
- ELZONRIS demonstrated efficacy (spleen size reductions and total symptom score [TSS] reductions) with a predictable and manageable safety profile, including in patients with poor prognostic factors, such as thrombocytopenia, CMML-type features/monocytosis, and clonal evolution
- 45% (9/20) of patients had symptom burden reduction, including 3 with symptom response per IWG-MRT 2013 MF response criteria
- 53% (8/15) of patients with baseline splenomegaly >= 5cm experienced a spleen size reduction; 20% (3/15) had a reduction >35% (specifically 100%, 47% and 46% reductions)
° 100% (5/5) of patients with CMML-type features/monocytosis experienced a spleen size reduction, and 40% (2/5) of these patients had a reduction >35%
° 64% (7/11) of patients with thrombocytopenia (platelet count < 100x109/L) experienced a spleen size reduction, and 18% (2/11) had a reduction >35%; 60% (3/5) of patients with thrombocytopenia (platelet count < 50x109/L) experienced a spleen size reduction, and 20% (1/5) had a reduction >35%
- Most common treatment related adverse events (TRAEs) include alanine aminotransferase increase, headache, hypoalbuminemia (all 17%), anemia, and thrombocytopenia (both 14%)
° There was one case of capillary leak syndrome (CLS), which was grade 3 - 43% overall survival (OS) at 18 months; 29% OS at 2 years
Next Steps
- Expansion of Phase 2 trial to include additional sites is underway
- Patient enrollment and follow up continues to inform design of potential registration-directed trial of ELZONRIS in patients with relapsed/refractory MF, including poor prognosis patients with:
° Thrombocytopenia, and/or
° Monocytosis (CD123-overexpressed subsets)
Other areas of evaluation in MF
- An additional ASH presentation demonstrated that ELZONRIS, either alone or in combination with ruxolitinib, had preclinical activity against primary MF patient samples, including those in accelerated phase and with high molecular risk profiles where current therapeutic options beyond ruxolitinib are limited and CD123 expression is evident. These data support further evaluation of tagraxofusp in MF, not only as single agent but potentially in combination with Jak inhibitors.
Multiple Myeloma: Clinical Trial of ELZONRIS in Patients with Relapsed/Refractory Multiple Myeloma (MM)
- ELZONRIS, in combination with pomalidomide (POM) and dexamethasone (DEX), demonstrated activity and a predictable and manageable safety profile in heavily pretreated patients with relapsed/refractory MM
- 56% of patients (5/9) who received ELZONRIS in combination with POM+DEX had partial responses (PRs)
° Notably, these patients also had decreases in their plasmacytoid dendritic cells (pDCs), a cell type implicated in myeloma growth and aggressiveness, and the cell of origin of blastic plasmacytoid dendritic cell neoplasm (BPDCN) - Given these clinical data, ELZONRIS may offer a novel mechanism of action and future therapeutic option for patients with MM
Next Steps
- Given these encouraging early results, potential avenues for further ELZONRIS development are being assessed, including evaluating additional patients with this and/or potentially other regimens including in combination with daratumumab or novel agents such as XPO1 inhibitors. Moreover, the clinical knockdown of pDCs in MM patients may also be relevant with respect to other diseases, such as chronic myelomonocytic leukemia (CMML), MF and certain acute myeloid leukemia (AML) patient subsets, where pDCs have been similarly implicated in the aggressiveness of these malignancies.
About ELZONRIS®
ELZONRIS® (tagraxofusp), a CD123-directed cytotoxin, is approved by the U.S. Food and Drug Administration (FDA) and commercially available in the U.S. for the treatment of adult and pediatric patients, two years or older, with blastic plasmacytoid dendritic cell neoplasm (BPDCN). For full prescribing information in the U.S., visit www.ELZONRIS.com. In Europe, a marketing authorization application (MAA) is under review by the European Medicines Agency (EMA). ELZONRIS is also being evaluated in additional clinical trials in other indications including chronic myelomonocytic leukemia (CMML), myelofibrosis (MF), and acute myeloid leukemia (AML).
About BPDCN
BPDCN is an aggressive hematologic malignancy with historically poor outcomes and an area of unmet medical need. BPDCN typically presents in the bone marrow and/or skin and may also involve lymph nodes and viscera. The BPDCN cell of origin is the plasmacytoid dendritic cell (pDC) precursor. The diagnosis of BPDCN is based on the immunophenotypic diagnostic triad of CD123, CD4, and CD56, as well as other markers. For more information, please visit the BPDCN disease awareness website at www.bpdcninfo.com.
About CD123
CD123 is a cell surface target expressed on a wide range of myeloid tumors including blastic plasmacytoid dendritic cell neoplasm (BPDCN), certain myeloproliferative neoplasms (MPNs) including chronic myelomonocytic leukemia (CMML) and myelofibrosis (MF), acute myeloid leukemia (AML) (and potentially enriched in certain AML subsets), myelodysplastic syndrome (MDS), and chronic myeloid leukemia (CML). CD123 has also been reported on certain lymphoid malignancies including multiple myeloma (MM), acute lymphoid leukemia (ALL), hairy cell leukemia (HCL), Hodgkin’s lymphoma (HL), and certain Non-Hodgkin’s lymphomas (NHL). In addition, CD123 has been detected on some solid tumors as well as autoimmune disorders including cutaneous lupus and scleroderma.
About Stemline Therapeutics
Stemline Therapeutics, Inc. is a commercial-stage biopharmaceutical company focused on the development and commercialization of novel oncology therapeutics. ELZONRIS® (tagraxofusp), a targeted therapy directed to CD123, is FDA-approved and commercially available in the U.S. for the treatment of adult and pediatric patients, two years and older, with blastic plasmacytoid dendritic cell neoplasm (BPDCN). In Europe, a marketing authorization application (MAA) is under review by the European Medicines Agency (EMA). ELZONRIS is also being evaluated in clinical trials in additional indications including chronic myelomonocytic leukemia (CMML), myelofibrosis (MF) and acute myeloid leukemia (AML). Additional pipeline candidates include: felezonexor (SL-801) (XPO1 inhibitor; Phase 1 in advanced solid tumor patients ongoing), SL-1001 (novel RET kinase inhibitor, IND-enabling studies ongoing), SL-701 (immunotherapeutic; Phase 2 in glioblastoma patients completed), and SL-901 (novel kinase inhibitor; prior abbreviated European Phase 1, IND-enabling studies ongoing). For more information, please visit the company’s website at www.stemline.com.
Forward-Looking Statements
Some of the statements included in this press release may be forward-looking statements that involve a number of risks and uncertainties. For those statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. The factors that could cause our actual results to differ materially include: the success of our U.S. launch and commercialization; the success of our MAA submission to the EMA and potential launch in Europe; the success and timing of our clinical trials and preclinical studies for our product and product candidates, including ELZONRIS in additional indications and our other pipeline candidates, including site initiation, institutional review board approval, scientific review committee approval, patient accrual, safety, tolerability and efficacy data observed, and input from regulatory authorities including the risk that the FDA, EMA, or other ex-U.S. national drug authority ultimately does not agree with our data, find our data supportive of approval, or approve any of our product candidates; the possibility that results of clinical trials are not predictive of safety and efficacy results of our product candidates in broader patient populations or of our products if approved; our plans to develop and commercialize our product candidates, including, but not limited to delays in arranging satisfactory manufacturing capabilities and establishing commercial infrastructure for ELZONRIS; product efficacy or safety concerns resulting in product recalls or regulatory action; the risk that estimates regarding the number of patients with the diseases that our product and product candidates may treat are inaccurate; inadequate market penetration of our products; our products not gaining acceptance among patients (and providers or third party payors) for certain indications (due to cost or otherwise); the risk that third party payors (including governmental agencies) will not reimburse for the use of ELZONRIS at acceptable rates or at all; the company’s ability to produce, maintain or increase sales of ELZONRIS; the company’s ability to develop and/or commercialize ELZONRIS; the adequacy of our pharmacovigilance and drug safety reporting processes; our available cash and investments; our ability to obtain and maintain intellectual property protection for our product and product candidates; delays, interruptions, or failures in the manufacture and supply of our product and product candidates; the performance of third-party businesses, including, but not limited to, manufacturers, clinical research organizations, clinical trial sponsors and clinical trial investigators; and other risk factors identified from time to time in our reports filed with the SEC. Any forward-looking statements set forth in this press release speak only as of the date of this press release. We do not intend to update any of these forward-looking statements to reflect events or circumstances that occur after the date hereof.
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