Xencor to Present Data from Phase 1 Study of Vibecotamab in Acute Myeloid Leukemia at the 2020 ASH Annual Meeting
Xencor, Inc. (NASDAQ:XNCR) announced that data from its Phase 1 dose-escalation study of vibecotamab will be presented at the 2020 ASH Annual Meeting. Vibecotamab is a bispecific antibody targeting CD123 and CD3, developed for treating relapsed/refractory acute myeloid leukemia (AML). Initial results indicate that patients with low disease burden and specific T-cell signatures may respond better to treatment. Toxicities were primarily mild-to-moderate, with cytokine release syndrome observed in 58% of patients. The study continues to optimize dosing and prepare for future trials.
- Initial Phase 1 results show potential efficacy of vibecotamab in AML treatment.
- Patients with low disease burden had better response rates, suggesting targeted treatment effectiveness.
- Primary toxicity from treatment was mild-to-moderate, with manageable cytokine release syndrome.
- Cytokine release syndrome occurred in 58% of patients, indicating significant treatment-related side effects.
- Despite some positive responses, overall efficacy remains limited with only 14% of patients achieving an objective response.
MONROVIA, Calif.--(BUSINESS WIRE)--Xencor, Inc. (NASDAQ:XNCR), a clinical-stage biopharmaceutical company developing engineered monoclonal antibodies for the treatment of cancer and autoimmune disease, today announced that data from the ongoing Phase 1 dose-escalation study of vibecotamab (XmAb®14045), a CD123 x CD3 bispecific antibody, in patients with relapsed/refractory acute myeloid leukemia (AML) will be presented in an oral session at the 2020 American Society of Hematology (ASH) Annual Meeting on Sunday, December 6, 2020.
"Data from the Phase 1 study of vibecotamab suggest that patients with AML having low baseline disease burden and specific T-cell signatures may be more likely to respond to treatment with vibecotamab. The primary toxicity, CRS, is generally mild-to-moderate in severity when observed and is manageable," said Allen Yang, M.D., Ph.D., senior vice president and chief medical offer at Xencor. "We continue to optimize dosing regimen in this study, and along with our partner Novartis, we are planning our next clinical trials to develop vibecotamab in patients, for whom an intermittently dosed, CD123-targeting antibody could be a needed therapeutic option."
Key Highlights from the Abstract
The accepted abstract is available on the ASH conference website.
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At data cut off for submitting the abstract, 104 patients with AML, one patient with B cell acute lymphoblastic leukemia and one patient with chronic myeloid leukemia had received vibecotamab. Patients had a median age of 63 years and were heavily pretreated, having a median of three prior therapies, and
30% (n=32/106) had undergone prior allogeneic stem cell transplantation. - Patients received doses of vibecotamab ranging from 0.003 mcg/kg to 12 mcg/kg. The recommended initial priming dose was determined to be 0.75 mcg/kg. A maximum tolerated dose (MTD) was not reached.
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Cytokine release syndrome (CRS) was the most common toxicity occurring in
58% of patients (n=62), and8% of patients (n=9) experienced CRS at Grade 3 or higher. The majority of CRS was observed on the first dose and was generally manageable with premedication. Additional adverse events consistent with CRS but not reported as such, including chills, fever, tachycardia and hypotension, were reported in an additional24% of patients. No myelosuppression requiring dose modification or evidence of tumor lysis syndrome was observed. -
At dose levels of at least 0.75 mcg/kg (n=51), two patients achieved complete remission (CR), three patients achieved a CR with incomplete hematologic recovery, and two patients or morphologic leukemia-free state (ORR=
14% ). - Patients with responses were characterized by lower disease burden and specific T-cell subtypes.
Presentation Details
- Abstract: 460
- Title: Complete Responses in Relapsed/Refractory Acute Myeloid Leukemia (AML) Patients on a Weekly Dosing Schedule of Vibecotamab (XmAb14045), a CD123 x CD3 T Cell-Engaging Bispecific Antibody; Initial Results of a Phase 1 Study
- Session: 613. Acute Myeloid Leukemia: Potpourri of Potential Practice Changing Studies
- Date & Time: Sunday, December 6, 2020, 2:30 p.m. PST
About Vibecotamab
Vibecotamab (XmAb®14045) is a tumor-targeted antibody that contains both a CD123 binding domain and a cytotoxic T-cell binding domain (CD3) in a Phase 1 clinical trial for the treatment of acute myeloid leukemia (AML) and other CD123-expressing hematologic malignancies. An XmAb Bispecific Fc domain serves as the scaffold for these two antigen binding domains and confers long circulating half-life, stability and ease of manufacture on vibecotamab. CD123 is highly expressed on AML cells and leukemic stem cells, and it is associated with poorer prognosis in AML patients. Engagement of CD3 by vibecotamab activates T cells for highly potent and targeted killing of CD123-expressing tumor cells.
About Xencor, Inc.
Xencor is a clinical-stage biopharmaceutical company developing engineered monoclonal antibodies for the treatment of cancer and autoimmune diseases. Currently, 18 candidates engineered with Xencor's XmAb® technology are in clinical development internally and with partners. Xencor's XmAb antibody engineering technology enables small changes to the structure of monoclonal antibodies resulting in new mechanisms of therapeutic action. For more information, please visit www.xencor.com.
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